Tesla High Voltage Battery Pack Information

Dry Fit/Wet Fit

We are getting close to the end of the process! In broad terms, we are going to:

Dry fit the main lid to be sure we are happy with how things are lined up and bend any metal flat while before we deal with glue
Apply sealant and set the main lid in place - then install the fasteners.
Dry fit the penthouse cover - the fuse cover should already be attached.
Install the fuse
Apply sealant to the penthouse cover and set it in place - seal coolant rapidmate and install the fasteners.

Dry Fit

There is a black bracket that goes across the front of the lid that has studs to hold the penthouse cover to the main lid. This bracket gets attached to the main lid at this stage and should be held on by a few nuts for now.

The bracket goes through the holes in this part of the lid.

This is a careful fitment because the HV bus and BMS cables go right through this area.

This is the bracket assembled. Notice the unique insulator in the center.

Compare this to all those detailed photos you hopefully took when you disassembled this area.

The bolts holding down the perimeter of the pack are M5 x .75 thread. Get 4 long bolts from the hardware store and cut the heads off. Hand-thread one in each corner to serve as guide pins. Have a helper help you lift the cover into place. Make sure you like the way it looks. Everything flat? Hand tighten in the passageway fasteners to make sure they line up okay. No bits from inside sticking up? Now is the time to adjust something, not after the sealant goes on.

Make note of where the cover fits near the penthouse. You will apply sealant to the penthouse area later in a separate application. The area around that bracket in the images above will also get sealant later. We are going to seal, install and fasten the main lid first. Prepare your bags of fasteners. Reacquaint yourself on where they go and make sure you have everything and know where it goes.

Wet Fit

Apply a bead of sealant down the center spine remembering how difficult it was to get off. Focus on the bolt holes - they are what needs to seal. Do the same on the ribs - again, you need the bolt holes to seal. Finally, go around the perimeter of the pack. When you are happy with the sealant, lift the lid onto the corner posts with your helper like you did for the dry fit. Start installing fasteners. Get them all started before you tighten any down. Once a few are in, you can remove your guide pins. Save them for the penthouse later. Make sure the Passageway Fasteners are fitting. Get them all started before anything is tightened.

Focus on the bolt holes

Too much makes a mess and too little leaves air gaps.

Ribs get the same treatment - not shown here because the photographer had his hands full.

The Passageway Fasteners

These are unique little pieces we haven't discussed much. I need to get some better pictures but these are the fasteners that go through the pack from the bottom through the top that allow you to pass the 12 E12 Patch Bolts up into the floor of the car. In the v1 packs they are standard thread and in the v2 packs they are reverse thread so they don't loosen as you are tightening. The tops seals with an o-ring against the top of the lid so the sealant around these isn't critical. The bottom part is captured in the base of the pack and seals with an o-ring around the side. You do want to put some Teflon tape on the threads where they meet so water doesn't get into the pack from inside the tube section of the fastener. Also, make sure you tighten these by hand before you press down on them. If you put too much vertical pressure on them, you can accidentally press the bottom part out of the pack which will cause a moment of panic. It just presses in and indexes on a pair of pins but the best practice is to not disturb the bottom half.

You will notice the ones in the middle have thicker tops and the ones at the back are thinner. The ones at the front never had their double-sided tape removed because they didn't get stuck to the bottom side of the plastic sheet. The two at the front go on in during the next step when we install the penthouse cover.

In the context of the wet fitment and lid reassembly, make sure these are all started before you tighten down any of the other bolts so the lid can shift a bit as needed. Because these seal with o-rings and not glue, get them all started, tighten all the other bolts, then remove them one at a time and add the Teflon tape as a final step.

At this point, the pack should be sealed along the back by the rapidmates, up each side, down the middle and out each rib. The 20,000,000 8mm and T25 fasteners should be tightened and 10 of the 12 Passageway Fasteners should be in and tightened down with Teflon Tape. This is a good time to gently tap any wrinkles in the edge with a hard rubber mallet. While the sealant is still wet, smooth out any ugliness you see with the sealant. If you run your finger up the lip under the side of the lid, but be careful to watch out for sharp spots. The final step is the penthouse cover!

The Penthouse Cover

Somehow Tesla designed this part with symmetry to allow the bolts to fit with the cover upside down so don't install your wrong! The hump should be facing up. Another way to think about it is you want the water to run off the cover and not puddle up in the dish that forms when it is in wrong. It is easiest to install the fuse cover with the penthouse cover on the bench. This will allow you to see the sealant come through on the back side and make better and more clean install. The fuse cover is sealed with Right Stuff from Permatex which is simply amazing - aptly named for sure! The leaks usually come through the mounting collar, not the lid mating surface so this gives you the best shot at a good seal.

Penthouse Dry Fit

This part is a lot easier than the big lid because it is simply smaller and easier to work with. Remove the nuts/bolts that have been holding the bracket to the front of the main lid. It should stay in place now. You can use the guide pins from the main lid to help get everything lined up. Set the cover on and make sure you like the fit. Like the main lid, now is the time to tap something flat. Spend a minute looking at the coolant rapidmate coming through the cover. Hand-thread a couple of the funny little safety screws to make sure everything lines up. If everything looks good, we are ready to finish the job!

Fuse Install

The fuse cover should already be on so before the final install of the penthouse cover, tyou need to install the fuse following all the PPE and safety guidelines.

Penthouse Wet Fit

Although the penthouse is smaller, it has a lot of various surfaces and funky unions. Add the grey sealant around the perimeter of the case and along the edge of the main cover around the studs sicking up from the plate. Add some Right Stuff to the bottom of the cover around the coolant rapidmate and some more Right Stuff to the top of the coolant rapidmate itself. Set the penthouse cover in place onto the guide pins and start a couple of bolts and nuts from the main cover plate. Move to the coolant rapidmate and get those screws started. Snug them down. Hopefully, you will see the Right Stuff squeeze out evenly. Smear this around with a gloved finger and add a little more if necessary being careful to not get any on the black cylinder of the rapidmate itself - you are just sealing around the base. When the rapidmate looks good, finish starting the rest of the nuts/bolts. Start the final two Passageway Fasteners to make sure they line up. Tighten the nuts/bolts/screws and smooth out the excess so it doesn't look ugly. The last step can be the Teflon tape on the Passageway Fasteners.

Be a little generous here.

Right Stuff on both sides of this will help you avoid leaks during the pressure test

Smear a little more Right Stuff around any gaps here.

Congratulations! You have sealed up your Tesla Battery Pack! Let the sealant dry overnight and then we can pressure test and see how you did!

Page updated

Google Sites

Report abuse