Heat Problems from Insulated Batteries?

[Username1]

For people who don't live in hot climates, cold weather poses a big problem for batteries. One obvious solution is insulating the battery case and adding a heater for when it's cold out.

My question is would heavy insulation ever be a problem in hot weather? The cells produce some heat of their own. Adding insulation and a heating pad is easy, but also adding a system to extract heat would be much harder. It would have to involve either some kind of moving parts to open air vents, or liquid cooling with a radiator. This adds significant weight, size, complexity, points of failure etc.

I guess this could depend somewhat on the cells and application. I'm talking specifically about PEVs like e-bikes, e-scooters etc. They tend to have batteries from around 0.5-4 kWh and use 1-2c for their continuous discharge rating. I'm just trying to get a sense of whether a heavily insulated battery would ever face heat concerns in worst case scenarios, like going purely full throttle from full to empty on a hot summer day.

 

[john61ct]

Yes.

Foam boards can be removable, and thus expose venting that is blocked when installed.

 

[DogDipstick]

YOu need to know when your cell begins to make heat.

Cells on my bike are very distinct in that they begin to make heat at about 4C. That is 100A, for me. No heat before 4C, 100A..... and when I run over 100A contin is the only time I see heat. ( 100A on a 25Ah cell, 4C)

Know when your cell begins to make heat.

Shown is a pic of my bike.

Also shown is a pic of a Lipo stack that complied when it tried to discharge at 50C ( 250A on a 5Ah cell, 50C) and then heated up significantly.

Watts / Ah dissipate power. Keep it under 6w/Ah dissipate power.

 

[amberwolf]

Honestly, if you're using batteries that get hot enough to need cooling, you're using the wrong ones, or not enough of them, for the application.

If you're limited to having to use them anyway, then you'll need to test your specific battery in your specific application with your specific insulation setup to find out what is going to happen.


My EIG pack on my SB Cruiser trike is inside the wooden cargo/seatbox which is insulated *against* the summer heat here in Phoenix, with about an inch of styrofoam on all sides. (primarily to help prevent rapid heating of the stuff inside when I have to park it in the direct sun for short periods while shopping, etc). It doesnt' get hot from it's usage, as it is always used well within it's capabilities, far below it's max ratings, so there's no worry that anything other than the external heat of the sun will warm it up.

 

[Username1]

My gut feeling was that it probably isn't an problem. I guess using high discharge cells would probably all but guarantee this wouldn't be an issue. I don't think cells are dumping out a ton of heat at reasonable discharge rates, and cells can handle a fair bit of temperature increase.