[Dadrick]

In researching batteries for use in a conversion project I have found very little in regards to pouch cells other than they exist. It looks like they started out as a promising alternative with lighter weight and equal power to prismatic cells, but never caught on in the EV conversion community. They do look like they are difficult for a DIYer to make into packs, is this the reason they have faded or are there others?

Thanks,
Dad

 

[dcb]

there are tons of conversions using nissan leaf or chevy volt cells, those are basically pouch cells with a case. Separating them back into pouches is a bit bothersome though so usually they are kept as modules. The case also provides some compression, which is good for pouches IIRC.

 

[Solarsail]

Somewhere I read that for pouch cells, compression is mandatory. Or they age too fast and it is a safety issue. I think it was on ZEVA.co.au

LiPoly don't need compression?

My understanding is that inside a prismatic cell is always a pouch cell.

I believe it is easier to make packs from 18650 cells than a pouch cell, unless the pouch cell comes with its own case, which makes it a prismatic, I suppose. Used automotive pouch cells are sold with their own casing.

 

[Dadrick]

@dcb - I guess I am "used parts" adverse, but I am shying away from salvaged battery packs. The main reason is you don't know where they've been and how they were treated. I know Leaf packs in particular are subject to degradation because there is no active cooling. I would rather spend more now then be constantly replaceing or worried that the pack was going to fail.

@Solarsail - I can see how the pouch cells would need some sort of containment. The flexible nature would cause them to bulge and settle; changing how the anodes, cathodes and electrolytes are dispersed. The lightweight is attractive but having to add compression negates a lot of that advantage.

I wonder if there is a method of constructing a pack along the lines of OEM technology but for us one-off types.

 

[Kevin Sharpe]

I guess I am "used parts" adverse, but I am shying away from salvaged battery packs. The main reason is you don't know where they've been and how they were treated. I know Leaf packs in particular are subject to degradation because there is no active cooling. I would rather spend more now then be constantly replaceing or worried that the pack was going to fail.

I've purchased several Leaf and Tesla battery packs without problems. The Leaf packs were easy, I used Wolf's Pack Sniffer (here), and car age/mileage as a guide. I was very happy with the results.

For the Tesla packs I just used the age of the car and it's mileage as a guide. Today I would happily buy individual Tesla modules from a reputable source like EV West although undoubtedly buying a wreck with a complete battery is the cheapest option.

One of the things I like most about OEM modules is the ability to replace them in the future... it's already difficult to find some early prismatic cells but I'm willing to bet I can buy a Tesla Model S module in 10 years time.

I don't know where you're based (can you update your profile?) but a quick look on eBay has a 2015 Leaf pack in the US for 4,500 USD (here) and another in the UK for 3,445 GBP (here). Both packs have been around for a while so a deal can be done