2011 Nissan LEAF Battery - Deep Dive

Hello, I am Professor John Kelly and this is  the WeberAuto YouTube channel in this episode we   will be exploring the high voltage battery from  the original 2011 Nissan Leaf electric vehicle.   Now this is one of the most controversial battery  designs out there mainly because of the lack of an   active cooling system to remove the heat from the  battery but we will look at the individual pieces   and totally reassemble this battery in this video  now before we get doing that I need to thank the   good people at Green Tech Auto hybrid batteries  we would not have this battery to look at today   if it weren't for the folks at Green Tech Auto  Hybrid batteries and what they do different from   other companies is they have deals with salvage  yards and and wrecking yards here in the United   States where they buy batteries hybrid batteries  and electric vehicle batteries from salvage yards   from vehicles that have been in automobile  accidents and they take them apart they test   all the individual cells or cell modules and make  sure that everything is in good shape if there's   bad parts they will swap them out with good parts  from other batteries they have obtained from other   self yards so if I was running a business that  sold used hybrid and electric batteries that's   exactly how I would do it Green Tech auto hybrid  has been in business for over eight years and they   have 19 locations in North America so check  out their website I put a link in the video   description down below so thank you to the  people at green tech out or hybrid batteries   alright let's start looking at some of the parts  the biggest and most obvious pieces inside the   Nissan Leaf battery are the battery modules so  this is one battery module right here and it has   a positive terminal a negative terminal and a  voltage sensing terminal and inside of this are   four lithium ion pouch cells very similar to this  chevrolet volt lithium-ion battery pouch so there   are two sets of these four of them in two pairs  of two so two of these are welded together and   then two more are welded together and then they  are put in series positive to negative inside of   one of these battery modules well I'm not content  with just having that be the the smallest piece   that we look at in this battery because there's  there's got to be some interesting things to   look at inside there so I decided I don't want to  open one of those battery modules up and and see   how its configured I want to I want to look at it  but the the housing isn't made to be opened and I   got looking real close an adit and if you look  real close right at the edge there it actually   looks like the edge of a can of tuna or some other  canned good and so I thought hey I wonder if I can   use a can opener to open that up now don't do this  a home folks don't use the can opener to open it   but when my wife wasn't looking I grabbed her can  opener and I used it on this battery module right   here and sure enough I was able to cut from the  top all the way down and around and back to open   up one of these modules now I say don't do this  at home because if you short-circuit something in   here there's a big risk of fire and I just highly  recommend that you do not even try that I did it   in an environment where it wouldn't hurt anything  unless I couldn't get out of the way fast enough   so let's open up a battery module of a Nissan  Leaf all right now there's some information I put   on the labels on the front of this battery module  that apply it to the rest of these battery modules   and the whole battery as a whole the first thing  is the nominal voltage is 7.5 volts and nominal   means it's neither charged nor discharged it's  just that's its normal voltage there are 48 of   these 7 point 5 volt modules inside of the Nissan  Leaf battery and that if you take 48 times 7.5   you get 360 volts as the nominal voltage for the  entire battery pack all right this battery pack   is rated for 24 kilowatt hours and 60 amp hours  so let's open this up and take a look inside as   I take off the front cover which was glued on this  blue piece of material here which I believe is a   heat transfer material has a real sticky tacky  adhesive right there and it was all I could do   to get this off without bending it it was it was  rough okay now I had to manually cut the aluminum   on the top to get the lid off but now we can rock  out the rest of it just like that and of course   the back side also was glued to the bottom of the  module housing and so I had to carefully take that   off to see inside now if you look closely at the  edge here you can see that there are one two three   four of the lithium ion pouches now there's  a top cover right here that comes off next just a little pocket screwdriver and some  little tabs to release on each side there   we go and I'll lift that up so now here's the  bottom view which we still can't see very much   and then there's the top view where we can  see some connections at the top here this   is only seven and a half volts I don't need  high voltage gloves I don't need personal   protective equipment you still need to not  let these to short out or touch something   conductive like the stainless steel top  of my workbench here you got to be real   careful and be cautious of those even though  it's just seven and a half volts all right   on the backside there is another little cover  plate to take off right there and now we can   see on the back some of the connections now I  wanted to make some sense of these electrical   connections and as I said before we have four  of these lithium-ion cell pouches in here so I wanted to open them up but they're glued  each one is glued to each other I'm sure for heat   transfer and so I thought well I've come this  far let's let's keep going there's some little   dowel pins that have to come out here the hold the  support housings for the electrical connections on   all four of these pouches so I have to take out  two on the bottom and two on the top dowel pins   now with that with those dowel pins taken out I  could see that I could get in and try to separate   it which eventually I got it separated but you  can't separate it without cutting the electrical   connections right here on the top so I cut between  here and here and here and here on the one side so   that I could open this up so I'm going to open  it now it opens like this so now I have two 3.75   volt pouches and notice this pouch in comparison  with the Chevrolet Volt pouch is much larger and   we would expect it to be the volt battery was  a smaller kilowatt-hour battery 16 I believe   in this one's 24 kilowatt hour so to make sense  electrically of how these pouches are wired as   I showed you on the Chevrolet Volt pouch there's a  positive terminal and a negative terminal sticking   up at the top of the pouch so you can see right  here one of the terminals coming up and it has   a positive symbol on a sticker right there so that  this pouch right here that's its positive terminal   and it comes up and if it is welded to this copper  bus bar that then has the positive terminal from   the front pouch welded together so that puts it  in parallel same with the two negative terminals   right there so these two lithium ion pouches are  in parallel with each other but then coming off   of the negative terminal we have a bus bar where  I had to cut the connections from the other pair   of cell pouches so they connect where I cut it it  connects right here and that is the positive two   terminals of a set of cells and the negative two  terminals are over here so negative positive that   positive connected to the negative of this other  set of cells and then here's it's positive so   we have two sets of two parallel cell pouches in  series with each other so two pouches in parallel   with each other here two more pouches in parallel  here and we just put the two in series with each   other with this one common connection fold it back  together to complete the cell module now I wanted   to know what is this Center screw here well that  Center screw on the front pouch just goes between   the center screw and the positive terminal and  the center screw connects to the negative terminal   of the front pouch and so that will give us the  cell pack voltage to parallel cell pack voltage   of just two of the four of these cell pouches  then if you go between that same screw and the   negative terminal through that bus bar that I cut  the connections on it gives us the voltage of the   other set of parallel pouches so it's just  the center screw and the negative we measure   the front two pouches and from the center screw  to the positive we measure the rear two pouches   on this module now there are two different part  numbers of the module on the early Leafs and the   only difference between them is which side is  positive which is negative you can see on the   positive side as a red terminal negative side  has a black terminal you've got to pay real   close attention to how these came apart inside of  the battery itself so you get your everything in   series with each other positive negative positive  negative positive negative otherwise you'll lose   some of your power by putting positive to positive  or negative to negative okay well that was scary   for me to disassemble as afraid I was going to  short-circuit something or catch something on fire   but it ended up being a good good experiment let  me grab a module that has not been disassembled   this one right here and let's take a measurement  from the center terminal to the negative Center   terminal to the positive if I go from the center  terminal to the positive terminal I read three   point seven nine four volts if I go from the  center terminal to the negative terminal I   read three point seven nine seven volts so three  millivolts point zero zero three volt difference   between the two sets of parallel pouches inside  of the battery module now there's a computer   called the lithium ion battery controller on the  end of the rear stack of battery modules and one   of the jobs of that computer is to monitor these  voltages and then try to balance them by keeping   the voltages within a certain range we want  these to be as equal as possible if you're   ever going to go in and replace one of these  modules or replace an entire stack of modules   then you need to make sure that the voltage of  the module you're putting in matches the voltage   of the modules that are already there otherwise  it will trigger our trouble code and may not even   let the vehicle move at all so I believe there's  a scan tool function to draw down the power of a   certain cell module and there's a other ways to  do it with resistive load as well but you you've   got to have these at the same voltage I forgot to  take one more measurement with the battery module   while it's here just both cells both parallel  cells put in series combined here so we'll go   from positive to negative we get seven point five  nine volts on this cell right here now according   to the scan tool data these can be the allowable  range are on the scan tool without triggering a   trouble code is as high as four point two volts  and as low as three point two volts okay as I   said before there are three one to three stacks  of these modules where we just stack up modules   this particular stack goes on the right hand side  of our empty battery housing over there this one's   our left-hand stack and this one in the rear is  called the rear stack so the right-hand stack is   six kilowatt hour rating the left-hand stack is  six kilowatt hour and the rear stack is twelve   kilowatt hour for a total of 24 kilowatt hour now  as I showed you on those modules each one has its   own positive and negative terminal positive red  negative black and these modules have to be put in   a certain order so that as we connect positive  to negative positive connect negative we put   everything in series to build up the total voltage  of this now in this stack here the right hand and   the left hand stacks there are 12 7 point 5 volt  nominal modules which means makes this module B   not up to 90 volts if it was totally connected  together which it is not right now all the bus   bars are removed so the highest voltage that  we have is the seven and a half volts that are   right here so we've got 90 volts here 90 volts  here that's 180 and then we have 180 volts on   the rear stack as well so 180 + 180 gives us 360  volts now as you could see on the side of these   battery modules I've known each one of them and if  you're doing any service work on this battery you   need to know which module is which because there  are up to five different trouble codes per set   of parallel cells which means up to ten trouble  codes per module and if you get a trouble code   for a certain module and you decide well I need to  go in and replace just that module which you can   do after downloading and purchasing hundreds of  dollars worth of Nissan Leaf service information   and training information the Nissan Leaf battery  was originally designed and still is to be fully   serviceable as far as going in and replacing any  part that you want I don't think it's had to have   a lot of internal pieces replaced the biggest  problem has been the the batteries own capacity   decreasing and decreasing the drivable range of  the vehicle but the point I'm getting to here   is the number or these modules are not numbered  and so there's this little map that I found in   the training material that shows as you can see  here sort of where each battery module is and so   it took a little bit of it of figuring out and in  interpreting to find that so if you look at this   battery stack right here the lowest battery module  number is module 37 right here and so we start at   37 and then go to 38 up to 39 over to 40 up to 41  or over 42 up to 43 over to 44 and then there's   a connection that comes down over here to 45 46  47 and 48 so that's 12 modules in a unique order   in which they need to be electrically connected  together with the bus bars now the left hand stack   is laid out differently than the right hand stack  they look identical but which module is which the   order that the modules are placed in series with  each other is totally different and then on this   giant rear stack right here module one is clear  down there on the other side and it just simply   goes two three four five six all the way through  module twenty four right here and then we pick up   module twenty five right here and that winds its  way through up to module thirty six which then   connects to module thirty seven and then all  the way through to module forty eight now on   this battery module forty eight is the overall  battery negative that you'll see will connect   to the junction block the inside the battery that  when turned on will send power to the inverter up   underneath the hood module number one down there  on the rear stack is overall battery positive   and so we'll see that here in a little bit so of  course there are specific torque values for each   one of these module bolts if I turn this module  just a little bit here I can take off since I've   already loosened the bolts what's called an end  bracket so if i loosen this up I can lift off   and end bracket and then just lift up one module  like this module forty six which is no different   than the one we just looked at and every one  of these modules are identical other than the   polarity which is positive which is negative but  the thing you need to know about assembling one   of these is that there are spacers there's a  module spacer in between each set of modules   so that when you torque the bolts down it's not  squishing the housings of the modules together   it keeps a little bit of an air gap between it  which I'm sure the intent was to help cool the   battery helped keep the battery cool but as I  mentioned at the start of this video there is   no liquid cooling system there's no refrigerant  type cooling system like some of the BMWs have   there's no air blowing through it like Toyotas  have there is nothing to keep this battery cool   when you put the lid on that battery case that  I showed you at the start of the video and bolt   it down it's a hermetically sealed no air in  or out there are some vents for atmospheric   pressure changes as you drive up and down high  elevation mountains and so on but that does not   allow airflow through the system and and so it's  just a totally sealed box and no place for the   heat to get out now he you can transfer heat if  you remember from basic physics at least my basic   physics through conduction where we physically  touch some hotter some item that's hotter to   something that's cooler and the heat transfers to  the cooler item there's convection where something   is really hot and it heats the air up around it  and then the error dissipates the heat and then   there's radiation like the sunlight where there's  heat being transferred as long as you're not in   the shadow well the majority of the heat transfer  through the the Nissan Leaf battery is conduction   to the outer housing and then convection to  the air and that's it which is unfortunate   for the the design as it's turned out to be if  you especially if you live in very hot climates   areas of the world where it's very hot that's a  problem for Nissan Leaf batteries if you leave   live somewhere temperate or cool temperatures  cold temperatures then you're probably alright   and haven't had any problems but I wanted to  show you there is absolutely nothing here to   remove heat except for just thermal conduction  and convection all right so there are two module spacers they have to be lined up with the  holes then we just start stacking the modules   on top of each other obviously we stack four up  over here we're only stacking two up here there's   a warning in the service information about proper  alignment of the modules themselves and I'll show   you what that what they're talking about there so  if I put these bolts down in and get them started   by hand there we go these bolts are started by  hand but I can still twist these upper modules   and they tell you don't put it together with  it twisted especially on this rear stack here   they want you to get a straight edge and put it  along the modules before you tighten the bolts   down they'll hold them all together in the stack  to make sure that everything is aligned properly   now disassembling these is easy you just undo the  bolts and take them out but on this rear stack it   has big studs that go all the way from one side  to the other and you're laying these modules on   their side and so it could be a little harder  to get them aligned as you put it back together   they recommend that as you disassemble it and  and remove the nuts from the studs that go all   the way through here that you put a big sense  strap around it to keep the modules from falling   apart whenever you're disassembling that because  if they start if they start to fall especially   if you're you've got some sort of a conductive  tabletop which you should not be using if you're   going to be disassembling those parts some of the  modules might fall and get somewhere where they   could short out or cause other type of damage so  we want these as straight as possible before we   torque them down and there is a specific twerk  for these I found it interesting in the Nissan   Leaf service manual they don't give you the bolt  torque for for these bolts they just say torque   the bolt and so I looked in the service manual  and tried to find torque specs a whole section of   specifications for torque I couldn't find it the  only thing I could find was a table with general   torque ratings for specific types of bolts so  if I just missed it please write something in   the comments down below but I could not find  the torque specs in the service manual however   in the instructor guide for the Nissan Leaf Evy  technologies both the 2014 version out of 2018   version it does give the torque specifications  which I was relieved to find and so the torque   spec on these hold down bolts right here is not  very much 9.6 Newton meters or 85 inch pounds   not foot-pounds inch pounds so that's between  7 and 8 foot pounds so if you have an inch   pound torque wrench 85 inch pounds let me grab  mine I'm going to Snug these up by hand first okay they just wanted to use a cross pattern as  you tighten these bolts down to specification so   we will go to 85 now if this was the end stack  nuts that we're tightening up on the studs that   go through they want you to do it twice they  want you to check the full torque twice okay so   this is the outside of the vehicle view of these  modules but now let's take a look at the elect   Kohl's side the inside view so now we can see all  of the terminals sticking out of the modules so   we've got negative and then that the center  voltage sensing terminal and then positive   so notice we have negative positive negative  positive and then down below we have positive   negative positive negative this whole row going  all the way across has the negative on the left   the very bottom row has the positive on the  left and this other one over here will be a   little bit different and so somehow we need to  connect the modules in numerical order together   in the proper series configuration so for that  there's a special bus bar that these batteries   come with okay this is the bus bar assembly for  this right-hand battery stack and as you can see   it has metal bus bars that will go from one module  over to the next jumping the big gap right here   and then it has short little ones right here that  go up and down to go to change rows to go from one   row to the next row and then it also has a whole  bunch of little tiny wires here for the center tap   on these modules for the voltage sensing between  the two terminals and so this harness or this bus   bar assembly here made by Yuzuki is the one that  goes on here it actually snaps in place over these   terminals that they have a little lip right there  and so we will set this down on here for those   of you thinking he doesn't have his personal  protective equipment or his high of all these   gloves on this is not high voltage so a word on  on high voltage the federal motor vehicle safety   standards define high voltage on an automobile  as anything sixty volts DC or higher or thirty   volts AC or higher the National Fire Protection  Association and the Department of Energy define   it as one hundred volts DC or higher for needing  personal protective equipment or half of that 50   volts ac for personal protective equipment needs  now that these are this is a DC battery so we're   below the 100 volts this is a 90 volt battery  right here because there's confusion between DC   and AC voltage levels that are safe I believe  that most vehicle manufacturers have picked   the 50 volt AC as the rule say anything above  50 volts you need to have personal protective   equipment on well that that's extra safe and  I'm not arguing with that it's just that the   DC voltage rating is typically almost double of  the AC voltage rating for personal protective   equipment so I'm I I do have insulated tools right  here I'm going to use to put this together but I'm   not not going to wear high voltage gloves until  we start connecting the 90 volt stack to another   90 volt stack into the 180 volt stack because  there's there's no need to do so so the bolt   torque on these little tiny bolts that holds each  bus bar to the positive or negative terminal is   5.5 Newton meters or 49 inch pounds which is less  than five foot-pounds well it's just a little over   4 foot pounds so most technicians don't even  have a torque wrench that goes to as little as   4 foot-pounds you need to get out an inch pound  torque wrench like I used to tighten those bolts   down and torque those so I'm going to put these  in and then we'll torque them the nuts that I'm   tightening these bolts down into are held in place  inside of the little plastic pieces coming out of   those modules so you don't want to use any type  of an electric or impact gun installing these   because you can or removing them either because  you can break that nut loose inside the plastic   all right so I've got all of the busbar bolts in  place and we'll torque those here in just a moment   now we need to put in the little screws for the  voltage sensing lines and they are torqued to an   incredibly low torque of 1.2 Newton meters or 11  inch pounds which is just one inch pounds shy of   one foot pound for those of you that speak foot  pound rather than Newton meters one foot pound   of torque is too much for the screws so just a  light connection is all they're looking for there okay all the bolts and screws are in just  need to torque them now let's see it was 49   on the bolts and 11 on the screws alright  this torque wrench right here goes to or   goes from zero to thirty inch-pounds so we'll  do the screws first at the 11 inch-pounds I   may have exceeded that just putting them  in with a screwdriver let's find out I   think I've got the wrong tip alright let's  try those screws again number one Phillips 11 so it was a little more than my screwdriver  did but I just put them in real light okay all   the screws are tightened to the monstrous 11  foot-pounds or inch-pounds 1.2 Newton meters   all right now the bolts for the positive  and negative connections are at 5.5 Newton   meters or 45 or 49 inch-pounds so I'll switch  to a different torque wrench because that one   only goes to 30 so this one goes to 75  so I'll sit it on set the pointer on 49   or five-and-a-half Newton-meters right in the  middle there and then we'll snug all these up okay all the bolts are tightened  all right let's take some voltage   measurements if we go from the overall battery negative right here with our meter on  DC volts to the stack positive over here we get   ninety four point two volts I told you before that  anything under a hundred volts you're not required   to wear PPE for by the Department of Energy  or the National Fire Protection Association   but the most of automobile manufacturers wants  you to wear it at 50 volts I just wanted to show   you if I touch the 94 volts right here it does  nothing to me but that's with my body and skin   resistance and so on it's not something I'd  recommend that you do I just wanted to show   you that it's it's it's a safe voltage in most  conditions all right so let's put these or no   let's take some more measurements so if we  go from I'll see this was battery negative   right here if we just go over to the first  bus bar there's our seven point eight volts   for that module we go over to the second  bus bar now they added together at fifteen   point six eight if we come back to the third  twenty three volts go over here to the fourth 31:39 fifty-four oh I skipped one forty-seven in 54 60 to 70 78 86 and finally 94 so it's  just in series we add 7 point 5 to 7 point   8 bullets apiece what we say this was per  volt per module 7 point 8 volts instead of   7 point 5 so it's slightly charged more than  the nominal voltage but not fully charged at   the 4 point 2 volts each by the way if it was  fully charged at 4.2 volts each 4.2 percent of   cells in each module so that's 8 point 4 volts  per module times the 48 modules that there are   so that's fully charged this would be 403 point  2 volts and if it was 3 point 2 volts per cell   it fully discharged times two parallel cells per  module that's 6 point 4 volts times 48 modules   307 volts 307 point 2 and fully discharged  but you normally don't want to go to fully   charged or fully discharged you want to keep  it between the 20% and 80% unless you've on a   road trip or just have no choice but to keep  driving all right well let's get this let's   get these covers on got an arrow pointing to the  front this is the front of the vehicle over here just like that one down below and one more over here okay so on this module here we have the module  negative and the module positive these 290 volts   between them this happens to also be the overall  battery negative right there so once again this   is our right hand module our left hand module is  just like it back here and then our rear module   I want to look at next just a little bit okay  right here on the end of the rear stack of 24   modules is the lithium ion battery controller this  is a computer that monitors this individuals cell   voltages of all 48 modules it has electrical  connections on the side and along the bottom   according to the service information and the  training guide that eye guides that I downloaded   it monitors the cell voltages individual cell  pair voltages so two for each module and the   temperature sensors that it has I believe this  has four temperature sensors on this early model   and later on they added more temperature sensors  it controls the cell pair voltage variation so   any difference between the two parallel cells two  sets of parallel cells inside the module it tries   to balance those out it also tries to prevent  over charging discharging and overheating of the   battery by controlling how much current can come  in and go out while driving while charging and so   on so now that I've swung this around we can see  this rear stack of 24 modules at 7.5 volts each   that gives us 180 volts between this overall  battery positive terminal right here and the   other end of the battery module for module 24  right over here 180 volts and so this one when   we go to hookup wires to it we'll have to wear our  personal protective equipment but even though it's   a 180 volts total if I come in with the multimeter  and we just start here at overall battery positive guess I better use the positive terminal  and we come down to the negative terminal   down here it's just seven point eight volts  for the one module if I pick a point halfway   across over here let's see where we are  right here there are 102 volts right there   yeah it's come over a little bit more  133 and all the way to the other end 188 point 3 volts so each individual module adds  another seven and a half volts alright so this has   the same type of bus bar and voltage sensing  system that we saw on that right hand stack   assembly over there there's nothing special about  this as far as the busbars are concerned it just   puts every other module or every module in series  with the next one oh let's see there's some covers   that go on this so as an up arrow up and up and  these all appear to be identical it does tell us   when we're removing these that we take off the two  outside ones first and then put on the middle or   then take off the middle one which means we'll  put on the center one first let's see up yeah   up right there maybe see if that works out over  here yes so now we are ready to put these three   stacks of modules into that empty battery case  now that were far from finished because that   just sets the modules in there then we have to  connect each module together we have to have a   service plug and a fuse we have to hook up all  the internal wire harnesses for monitoring all   of the internal voltages and connect that to the  lithium-ion battery control computer right here   this does have a battery heater if you have the  cold weather package on the 2011 it came standard   on 2012 and above models I believe unless you  live in a well elite for certain geographical   regions of the of the world alright now each of  these modules to lift them up and put them in   the the battery housing or they're very heavy  so there's there's a hole right here there's a   hole right here in these end brackets so there  are four holes on each of these end brackets   for these modules that will use a engine crane  to come in and lift those up and set them down   in to the battery housing lower housing itself  so now let me reposition the the housing and   the get the crane over here and we'll get these  hooked up and set in okay I brought our engine   crane in I've got our crane scale turned on so  we can see how much each of these module stacks   way and so we'll just get these straps hooked up  here with these hooks these straps are rated for   3,200 pounds the way I have them looped through  the hook here and we're way less than that here   so there's no danger of straps giving away all  right well Center the crane the best we can take the slack out of the strap there we go  mr. crane forward just a bit and lift it up   straighten this out just a little bit there  we go all right it looks like we're reading 119 note 120 120 pounds on the  right-hand module stack so now   we'll just move this over to  the battery tray and set it   in on the right-hand side with this in  the front the tall section in the front so this stack is going to go right here  except this is the front and that's the   front I need to now I will just spin  the load around bring in the crane right there start there bring it down  slowly there are some guide studs down   inside of the housing here that will  line that up with once it gets down and just like that all right let's get this table out   of the way for a moment let's come in  and get the left-hand stack next okay I'll Center the table a little better under  the crane the scale on this one is reading   one hundred nineteen point five thousands so  let's put that in the battery housing next just like that all right now we're ready for that rear stack  okay we've got our rear stack sitting right   here if we look at the crane scale we are at  229 229 pounds and we were 120 pounds a piece   on the side stacks so 120 plus 120 is 240 plus  another 230 gives us 470 pounds of cell stacks   now according to the specifications from the  Nissan service information this entire battery   pack and housing and everything weigh 660 pounds  so there's another 190 pounds of bottom tray   upper cover and internal pieces that have to  go together now I did measure the bottom tray   to see how much it weighed if you look at this  photograph here you can see that also underneath   the bottom tray there is a center of gravity mark  it looks like a almost a little star type compass   that you want to position your lifting table  underneath because the rear stack of course   weighs more than the front two stacks Earth's  in its position towards the back of the vehicle   as well so you don't want the center your table  under the center of the battery as you lower one   of these batteries down out of the car you want  to Center it under that center of gravity mark   alright well let's set this in the battery tray  and move on alright let's bring it down there's   a couple of alignment studs on the back here  to line it up alright ok we finally have the   right hand stack the left hand stack and the rear  stack installed in the bat lower battery tray now   we need to install all of the wiring that connects  these cell stacks together to combine and and give   us in a big series circuit the three hundred and  sixty volts we have to have a way to connect to   the outside of the battery and run cables to the  inverter assembly that drives the electric motor   we have temperature sensors we have to install we  have battery heaters we have to install we have   the junction block with the positive negative and  pre charged contactor pre charge resistor we have   some structural supports that go in here and all  of that is coming up next alright before we start   putting the wire harnesses in and connecting  all these module stacks together we have to   bolt down these module stacks to the housing so  there are both nuts and bolts that need to be   put on to hold each of these stacks to the lower  battery tray so let me get those installed next you okay I've got all the nuts and bolts started  I'm going to use my electric drive gun here to   slowly run them down to where they bought them and  then we'll come back around with a torque wrench okay all the big studs and the bolts they'll  hold down these battery stacks are torqued   to 9.6 Newton meters or 85 inch-pounds not  foot-pounds so we'll get these torque next okay I've got all the module stacks bolted down  with their numerous bolts and studs and ready to   move on to the battery heater system but there are  some brackets that I have to install on the rear   battery stack there in order to make room for  the battery stack heaters and the wire harness   retainers and so on so let me get these brackets  installed next so there are four vertical brackets that use the dark-colored nuts to be held  in place and they go every other set of   studs if I would have been thinking  I would have put these brackets on   first before putting the battery stack  down in the battery tray but I forgot all the brackets all the rest of the brackets  that go on here and the ones I just installed   have the same tightening torque of 9.6 Newton  meters or 85 inch-pounds we have to tighten or   torque these brackets first before we put on  the next brackets all right the next bracket   we put on is to support the battery heaters on  the rear stack that go over the top on both the   driver side and the passenger side it is retained  with the light-colored nuts rather than the dark   ones okay now we have battery heaters to install  there are six eight of these battery heaters six   of these smaller ones for the two side stacks  the left stack and the right stack and then   two great big ones for the rear stack for a  total of eight heaters so this is the right   side stack heater notice it has orange wires  going to it it is fed power off of the high   voltage battery itself so these are high voltage  heaters so we'll set those in place where they go each of these heaters has a stud that we have  to put a nut on to hold it down so that was the   front heater this next one here is the center  heater heater number three just like that then   we have side stack heaters for the very back  of these side stacks just like that and like   that and then for the rear battery stack we  have the left and right upper heaters a kind   of an interesting thing about the operation  of these heaters in the instructor guide and   service information that I've have access to it  it says that they don't turn on until a negative   17 Celsius or 1.4 degrees Fahrenheit and the  purpose of these is to keep the electrolyte in   those cell pouches from freezing so they turn on  at one point four degrees Fahrenheit and turn off   at fourteen degrees Fahrenheit so they're not  going to feel warm to human touch when they're   on but their job is to just keep that electrolyte  from freezing and it uses power from the battery   itself and it does not need to be plugged in for  this to work this will continue working drawing   power from the battery it's my understanding  until the battery state of charge gets down   to thirty percent and then at that point it  shuts the heaters off to preserve what little   life there is of the battery left and then if it  still gets too cold it's just going to freeze and   damage the battery so you should always keep  your car plugged in if possible especially in   cold weather so it's just a resistive element  type heater we can't really see the resistive   elements we just have this aluminum plate that  the elements are sandwiched between so let's   let's take one of these apart and take a look  at it so it's just got a couple of wire ties   holding the harness in place so we'll lift that  harness up out of there just like that so it has   two tabs that have to be pressed and released in  order for the element to slide out it's almost   a three handed operation there we go okay so it  just slides over a little bit and then lifts out   okay looking at this heater element here it looks  like we have a power wire that comes in and feeds   the outside one the middle one and the other  outside one with battery positive high voltage   battery positive it looks like the resistive  elements all connect together underneath down   here electrically and then the return-path  are the two wires right here that go back to   battery negative an interesting little heater  element assembly so the whole element assembly   just fits on top of the rear battery stack as I  said before we have one for the right-hand side like that and this other one that we took  apart for the left-hand side okay let's   put this heater element back in the housing  just bring it in and slide it forward until   it stops and then our harness get it back  where it's supposed to go just like that so we will set this right over here on its  installation studs all of these heaters that   I just installed all eight of them are held  down with the light colored 10 millimeter   head nuts we'll get those installed and torque  to the same 9.6 Newton meters or 85 inch pounds okay we've got all the battery heaters bolted  down and torqued and now the next thing to do   is bring in the battery heater wire harness  okay this is our battery heater wiring harness   and it makes a connection of course with  every battery heater it makes a connection   up front here where the junction block with  the contactors goes because that's where it   receives its power after the contactors are  enabled and then we have a controller that   is going to control the heater that plugs in  also so let's get this set in place the power   source harness side that there's a left and  right side here has to go on the driver's side so I've plugged in our wire harness from the two  rear heaters into their brackets and now we'll   bring in the heater harness and then the supply  power for the left and right rear stack heaters there we go and then as I said we have  a left-hand side heater harness and the   right-hand side heater harness these have to  go in underneath everything else all the other   brackets and other harnesses that we put in here  it's clear down to the very bottom so I'll have   to lift up other harnesses and tuck it down in  it has some little Clips harness clips that hold   it in place another one and we supply power to  the front heater with this connector power to   the other front heater with this connector  get our harness clips into their brackets we have right-hand rear power here to the  right hand stack and rear power to the left   hand stack and we've got the center heater  with its connector plugs into a bracket clip   on the driver's side left hand side and then the  center heater connector on the right hand side just like that and plugs into a bracket down below there we go alright so now  the only loose harnesses we have are   the two control harnesses and our voltage  sensing harnesses and the power feed for   the battery heater okay now that we've got  the battery heaters and the heater harnesses   all installed there's a big structural  support member that goes left to right   I believe to protect the battery in the  event of a side collision so this goes in   after the wire harness for the battery heater  otherwise you won't be able to get it installed two big studs with nuts to be  installed on the outside edge   and four bolts that supported in the middle here all right well torque these Center bolts to the  same 9.6 Newton meters okay well tighten these   two outside nuts on the studs to 25 foot-pounds  or 33.9 Newton meters okay before we can install   the rest of the wire harness there are some  additional brackets that need to be installed   here let's get those in place this front one  here that I'm installing is for retaining the   hybrid or is for retaining the junction block  with the contactors in it so we'll set that   down there then we've got another bracket  for the rear back here that helps hold wire   harnesses in place get these bolts torqued to  the same 9.6 Newton meters okay next we have   one two three four temperature sensors for  this entire battery pack two of them go in   the rear stack and then one on each of the left  and right stacks so let's get those installed this one measures the temperature of  module 44 this rear one measures the   temperature of module 1 the very end 1  and module 12 one right in the middle module 1 and then module 12 and then just a bunch  of clips to hold the harness as we run it all the   way over to the end over here where the battery  computer is going to plug in and then the last   temperature sensor is for module 27 which is  this bottom one here on the driver's side Center   a couple of brackets alright we have one more  part to install now this is the battery heater   controller has a contactor a relay as they call it  here and a little computer processing unit it has   an external interface connection right here with  the lithium-ion battery controller and then these   two brown connectors right here one of them is the  input from the power from the contactors up front   and the other one is the output to all of the  heater modules themselves so this sits right here plug in our two brown harnesses here and then  it has three nuts that hold it in place making   sure that we're not pinching any other harnesses  underneath it all right we'll get those torqued in place okay the next thing to install is called  the battery junction block and if I take the   cover off of the battery junction block you can  see in here that it has a positive contactor   right here a negative contactor right there  it has a pre charged contactor right there it   has a pre charge resistor underneath it with the  resistance of 30 ohms we have our heater battery   heater power that comes off of this side we have  a current sensor right here that is used by the   battery controller for monitoring how much  currents going in and out and then we have a   low voltage connection right here connected to  the computer that is used to control all three   of these contactors and measure the amount of  current through this current sensor here and if   you're not familiar with a battery junction block  I've covered this in many of my other videos but   basically what we have on our on the end of the  junction block here is we have I'll make sure I   got the polarity right overall battery positive  from this entire battery here will connect right   here overall battery negative will connect right  here now this positive right here when we engage   the positive contactor will be connected to  this output terminal over here so right now   there is no connection between this side and  this side no connection but if we turn on that   positive contactor it will connect this side to  this side this is the output that goes on under   your car in the big high-voltage orange cables  up to your inverter assembly that is and your   DC to DC converter and air conditioning driver  and everything else and but more importantly to   the electric motor to make the vehicle move  on the negative side the negative contactor   right here when it turns on connects battery  negative on the input side to battery negative   on the output side for the inverter as well so  just it's just bigger looks a little different   than other battery junction blocks but it has the  exact same parts it works the same way and so we   will install that here next in preparation for the  high voltage harnesses to be connected so there   are just four nuts to hold this down on studs I'll  get these torque to the same torque as the other   bolts the 9.6 Newton meters all right with the  Junction block installed I can now connect the   high-voltage power connection from the junction  block to the battery heater controller but none   of that is live at the moment because there's  really no power here at the junction block okay   finally the main harness can be installed this end  of the main harness connects to the lithium-ion   battery compute or controller and the other end  connects to all of the voltage sensing lines on   the battery module if we remember there's that  little Phillips head screw in the middle of the   to the the battery positive and the battery  negative terminals on each module these wires   connect to that screw and to one of the positive  or the negative terminals on that same module so   that it can measure both voltages so when we start  plugging these in that's when we're plugging in   high voltage connections because those are live  connected to the battery right now so I'll have   to have my personal protective equipment gloves on  at that point this black portion of the harness is   the low voltage harness and it connects to all  of the temperature sensors the heater controller   and the junction block up front that we just  connected or installed and then it connects to   an external harness that will go out the front of  the battery itself so let's get this in installed   next alright we'll plug in our temperature  sensors on the rear here anyway or in the middle rear temperature sensor harness low voltage  alright there's one more component I forgot that   I could install without high voltage gloves  on it at the moment and this is the front   electrical connector there's two pins right here  for the battery positive and negative positive is   this terminal negative is this terminal once  power is transferred through the contactor   contactors and this is the low voltage harness  connector that connects to this harness right   here this little tiny two terminal connector  right here is called the interlock circuit   and it connects right here on this harness the  interlock circuit will detect when someone has   unplugged the electrical connector right here  without powering down the system properly and   if it detects that then it automatically  shuts off the high voltage contactors the   positive and negative contactors in the junction  block to remove power so that you don't get DC   arcing as you are unplugging the connector in  a possibly live circuit which is a really bad   and dangerous thing to do so now this is going to  stick through the front so I just installed this   and now we've got a ground strap right there  that will install and I'm missing four nuts alright as you can see there are four studs right  here that are missing nuts and I'm usually pretty   good at keeping things organized I couldn't find  the nuts and so one thing that I always do before   disassembling anything is to photograph it take  a lots of photographs and it turns out when this   battery arrived those nuts were missing they  just weren't installed so I've got some other   nuts that'll do the trick but they're not the  correct and not for the this application but   it's the same thread so I'll get those installed  we've got to install the two bolts that connect   to the contactor output to this connector  here now and we can get everything torqued   now we can connect this low voltage harness to  the output connection finally that was a rough   one and then our interlock circuit connector  right there all right and then our low voltage   control harness from the battery computer to  the contactor assembly to control those all   right I'm ready to get my high voltage linemen  gloves on with the leather outer covering this   box of gloves I purchased earlier this year it  has a five of nineteen date on it and this is 12   of 19 and if you've heard there's a six month  expiration that's true but it's only from the   day that you opened them and first used them so  we actually received them on eight twenty nine   of nineteen and according to OSHA they can  sit unused in their box for up to one year   before opening them and then you still have  six months after that so these are brand new Salisbury linemen gloves normally there's an  opening you can just slide them right out of there   but they seem to be welding the plastic now to get  the or to keep them in in good shape in storage so   very carefully so I don't cut the the gloves or  myself I'm going to open that bag it's kind of   interesting in the Nissan's service information  and the training material in particular they only   showed photographs of technicians using these  lineman gloves with no leather outer protectors   well that's that's against OSHA regulations  here in the United States I don't know what   the regulations are in Japan if that's where  they developed the training but these gloves   can be damaged quite easily and I have a separate  video on personal protective equipment and how to   check high-voltage gloves and so on but you just  want to inspect them blow them up look look and   listen for leaks before you and stuff before  you put these on your hands and basically put   your life in your own hands every day so I will  get these checked and get them on now according   to OSHA there's only one exception where you can  use the gloves just by themselves and that is if   wearing the leather outer protectors makes it  too hard to get in and manipulate small parts   but it also says once you do that these gloves  are no good you have to either replace them or   send them out to be recertified not just you doing  an inspection but an actual electrical insulation   recertification so that's an expensive decision to  make so always wear your outer leather protectors   as you work on high voltage circuits by the way  high voltage in the outside of the automotive   world is not 400 volts this is considered low  voltage these these gloves are rated for 1000   volts and somebody put a sticker over it but  they actually say low voltage right on the   the box itself so anything less than 1000 volts  but remember I said according to the National   Highway Traffic Safety Administration Federal  Motor Vehicle standard 305 I believe states   that high voltage in the automotive world is  anything higher than 60 volts DC and 30 volts   ac alright well we've talked about that already  we are ready to start connecting all of our high   voltage sensing lines and then we'll get out the  great big battery high voltage battery cables that   connect the individual stacks to each other so  let's get these voltage sensing lines connected   so this harness here is the voltage sensing lines  for the 24 rear modules and then that goes right   over to the the computer this harness here that  I'm going to plug in next is the voltage sensing   lines for the right-hand stack and then this other  harness here is the voltage sensing lines for the   left-hand stack so all of those are connected  now so now we have two great big orange cables these two cables are what connect the  overall battery positive on the right   rear of the rear stack they're all the way up  to our contactor assembly and what connects   the overall battery negative to the contactor  assembly as well through the service disconnect   lever that we still have to install here  so let's get these two cables installed and then as you can see this cable will  come all the way forward and connect to   the input of our contactor assembly here our  junk Junction block but we have to install   the service disconnect lever because it's  got some harness hold down clips in there   that we need to connect as well so now we'll  install this big heavy cable here this will go   from module 24 at the left rear to the service  disconnect lever that we have to install next it is now time to bring in our service  disconnect connector and lever right here   the service disconnect connector has two  terminals underneath it right here these   two and when the service lever is installed it  connects this side to this side or just connects   the two together so we are going to use this  to connect to that last cable we just installed   and then another one to connect to the battery  and this when this lever is removed creates an   open circuit just like it is right now inside of  the battery which reduces the overall voltage of   the sections instead of it being 360 volts at  the contactors it would be zero but it really   divides it into let's see it would be a 100 or  no 270 volts section and a 90 volts section is   what it would divide it into alright the  service disconnect lever itself right here   I've opened it up which you're not supposed  to do and it has a 225 amp 450 volt inside of   it so here's the bottom view and so this goes  right in here except I may have it backwards just clips in place just like that the two  little tiny terminals right there that's the   another interlocked circuit so if you disconnected  this before you were supposed to the interlock   circuit would disconnect first and it would kill  the power to the contactors which would prevent   arcing as you move this which is why you must  wear high voltage gloves when you remove this   just in case there's live circuit DC arcing in  a live circuit is is frightening there's videos   all over YouTube of DC arcing take a look at it  it'll make you want to wear your gloves alright   so I'm going to install the connector but not the  service lever until we're done with everything   okay when installing this service disconnect  lever connector we have a bus bar that's going   to go from the connector over to module 25  the big harness the big cable that we just   installed the shorter one comes from module 24  so remember everything is in series so we have   module 24 coming in here it connects to module  25 it's just a big series circuit but when the   service disconnect lever is removed the this  series circuit is opened alright let's see if   we can get this cable connected now bring that in  underneath put the rub rubber cover back over it   there we go and now we can set this straight down  and into and over the heater get our connection   made here at module 25 looks like we did so  now if we can install the nuts that hold that   down and the nut for the connection on module  25 I forgot to hook up the interlock circuit to the bottom of the connector there  so we gotta take that cover her that   bracket or take the bracket bolts out  just long enough to plug that back in okay let's take that out and plug that interlock  circuit harness into the service disconnect lever   connector so we'll just lift this back up this  little white connector right here it's gotta   go in and plug in right there okay now we can  put this back in if you leave that interlock   connector disconnected like I accidentally  did there the vehicle would never power up   because it would immediately see there's  an open interlocked circuit which should   always be closed or a big series circuit  and it would never enable the contactors   to close so there'd never be any power to the  inverter to make the vehicle move so it's a   very critical circuit okay we're just about  done we have two more bus bars to install to   put more battery modules in series with each  other to increase the voltage and to connect   the overall battery negative terminal  over here to our contactor assembly here so I've got one bus bar that connects module  36 to module 37 36 is right here on the right   so this is going to go across here let me get  this big cable from battery positive down on there we go okay so 36 to 37 here  too right there and then module 48   to battery negative so overall battery  negative looks like I better put it   on first all right it looks like this  bus bar should have gone on before the contactors would have made it a lot easier this  is not impossible but it's less than ideal there   we go okay so there's our negative terminal bus  bar connected so now we can connect the rest of   these or put the nuts on the rest of the bus bars  and get module 36 here connected to module 37 let's get those torqued get these back ones here  as well and one more to torque right over there   module 24 okay the last internal piece to install  is the lithium-ion battery controller computer   and he has all the electrical connections for  the voltage sensing circuits the temperature   sensor sensing circuits the contactors and the  interlock circuits and external communication   now the service information warns us that we  should always disconnect this first and install   it last otherwise damage to the computer  can occur so we connect the high-voltage   lines first and then the low-voltage lines  it has four bolts that hold it in place two bolts in the back okay these are  only torque to 5.5 Newton meters and   then finally the last two electrical  connectors the low-voltage ones for the lithium-ion battery controller and there we  go alright the last internal piece to install   except I'm not going to install it yet because I  need it off for demonstrations in my classroom in   my classes is the junction block cover that  covers up the contactors and the electrical   connections and and so on but I want to show  you the function of the service disconnect   lever and the contactors themselves and so  let me grab a multimeter okay just a quick   word about multimeters they need to be rated  category 3 1000 volt for this type of work   and a good quality meter a good name-brand meter  who has had their meter tested and certified by   some sort of service certification organization  such as underwriters laboratory or the Canadian   standards Association or Intertek or whomever  to make sure that this meter is following all   of the insulating and personal protective  requirements laid out by the International   Electrotechnical Committee and that's for your  safety meter leads wear out over time the real   flexible ones the the strands can break and you  need to make sure that your meter is clean and   in good shape you also need to verify that  your meter is capable of reading accurately   before you bet your life on some sort of a reading  that your or measurement you're going to take on   the battery so for example on these these front  two terminals right here it's showing zero volts   but am I sure that the meter is even working am I  sure that the leads are in good shape so the best   thing you can do is test it on another battery  just a 12 volt battery 9-volt battery whatever   fluke does sell what's called a proving unit  I've got one of these right here as part number   pr8062403 in this proving unit but looking at  the screen of my fluke 87 here we go 236 volts   so we know that the meter is capable of reading  a high voltage not just nine volts not just 12   volts and and as I said this can do AC voltage  as well but we're dealing with DC right here on   this battery so I'm going to switch meter leads  or ends of the meter leads to alligator clips   and even the tips and ends need to be certified  I have a separate class where we talk about that so I've got alligator clips and I'm going  to put the red clip on the overall battery   positive connection right here at the contactor so  right there and then the black alligator clip and   meter lead to the overall battery negative side  right there alright as you can see the meter is   reading well 320 millivolts thousandths of a volt  so this is less than 1 volt so now I'm going to   come in with the service disconnect lever and  plug it into the connector and now we should   get the 360 or whatever volts proving that the  service disconnect lever fuse is good and that   it's an open circuit at the moment so here we  go it's plugged in we are now reading 376 point   6 volts at the input side of the contactor with  the service plug installed as you can see there   alright now I'm going to move these meter leads  to the output side of the contactor and I want   you to notice that now the meter now the meter  shows pretty much 0-3 millivolts no power no   voltage and that proves that the contactors are  open they're not allowing that 370 whatever volts   to be present on the output lines which means the  voltage here on the front of the battery is also   0 so the contactors do a good job of opening the  high voltage circuit there when we do service work   or on the vehicle and we want to disable all of  that then we just remove this service plug lever   when told to buy the appropriate service procedure  but you don't always do that there's there's times   that you'll want that plugged in for Diagnostics  but the important thing to know is that when you   do remove that it opens circuits the inside of the  battery and there will be no or there should be no   power on this output but you should always use a  qualified tested multimeter to verify that there's   no power there before you disconnect or any other  components or go inside and assume that something   is D powered without checking it first I'm going  to remove the service plug lever push on a little   tab rock up and pull alright just a couple more  things and we're finished I want to call you to   your attention the seal right here around the  outer edge of the lower battery tray this seal   on the first versions the first version 2011 and  12 of the Nissan Leaf it was designed to with the   upper cover put on keep out moisture and dirt dust  whatever and it needs to be checked to make sure   that it is sealed properly so right here on the  front of the battery is an air leak check plug and   what you do is you take this plug out this plug  has a gasket on it a copper gasket just like a   oil drain plug or whatever transmission drain  plug come on these gloves are slowing me down   okay so there is the air leak check plugged and  there's a special service tool that you screw into   there with the cover on and all the bolts torqued  down there's a proper tightening sequence for that   upper cover and then you connect compressed air to  it through a special low pressure regulator that   limits the maximum pressure to two kiloPascals  which is the same as 0.23 psi pounds per square   inch extremely small amounts of pressure and so  you're supposed to pressurize it then block off   the air pressure and it should not drop below  zero point two psi if it does then you've got a   leak somewhere and you need to go double-check  your gasket and so on on the 2013 later models   that got rid of this gasket and went to a  urethane adhesive that you have to cut to   remove the upper cover and then clean it all up  and reseal it when you go back together but all electric vehicle batteries that I've seen that  are mounted under the vehicle or outside of the   passenger compartment have some sort of a leak  check procedure the General Motors products pump   evaporative emission testers smoke in and you  look for a smoke leaking out and then you flush   it all out with nitrogen when you're done I  don't know what Tesla has on theirs because   it's it's not a user serviceable battery but  I'm sure they have some sort of a leak check   procedure as well just to make sure that the  entire battery is sealed you it if you don't   keep it sealed then water and dust and everything  else will get in which can cause electrical short   circuits and malfunction computers and all kinds  of problems you don't want to have inside of a   battery so that one of the last things you do  is make sure that it holds pressure verifying   that it is properly sealed all right this has  been a really long video a big long service   procedure of putting one of these back together  that almost anybody can take one apart big deal   just take the bolts out and start pulling  and enterin and so on but putting it back   together and having at work when you're done is  a different story and it's it's critical that   you follow the proper service information  and torque bolts especially the electrical   connection bus bar and and cable bolts so that  we don't get any poor connections which end up   causing unwanted resistance and unwanted to eat  melded connections possible fires and so on all   right well once again I'd like to thank Green  Tech auto hybrid batteries for letting us have   them play with this battery here this year  greatly appreciate that I appreciate you as   viewers in watching and supporting this channel  thank you for watching and have a good day you

Channel: WeberAuto

Views: 238,296

Rating: 4.9045744 out of 5

Keywords: WSU, Weber State Automotive, Weber State University, John D. Kelly, Nissan Leaf, Greentecauto, Wheelchair, Professor Kelly, Passive Cooling, Battery, Li-Ion, Pouch cells

Id: vYQJatWpBXY

Length: 112min 33sec (6753 seconds)

Published: Tue Dec 10 2019

Reddit Comments

[u/SkyNut]

Much respect to Weber Auto for all his quality content. He really knows his stuff!

[u/sincebolla]

My alma mater!! Weber State, Weber State, Great Great Great!

[u/[deleted]]

I know little about EVs, but lets say I purchase a used Leaf somewhere, and it turns out one (or few) of some cells are bad in the battery. Can I just buy a replacement cell from somewhere and slap it in-place (after doing voltage calibration)?