The "thermal management of LiPo" thread!

[Punx0r]

I've only seen an 26650 pack immersion cooled, but the Koenigsegg Regera appears to use immersed (or "flooded") pouch cells: https://www.koenigsegg.com/regera/

 

[LeftieBiker]

Cooling any battery will make it last longer.

This, like "using a BMS will make any battery last longer" ignores an important factor: Chinese quality. Many, many people have lost packs early in their projected cycle life because the BMS malfunctioned and killed them. Likewise, a cooled pack becomes subject to increased risk of liquid infiltration (and possibly fire) that doesn't even normally exist. Using a pack that's large enough that it isn't under too much thermal or charge/discharge stress, and keeping it generally between 25% and 80% SOC, is the best way to prolong battery life.

 

[Punx0r]

Hermetically sealed cells (i.e. any one made correctly) isn't at risk of liquid infiltration. Risks of electrical shorts from coolant contacting electrical connections in the pack are mitigated by using a non-conductive coolant.

For sure, an active cooling system on a small pack doesn't make sense - the mass and volume of the cooling system would be better spent on more battery to lower C-rates. However, that's less true on larger packs, which are also less able to shed heat effectively by natural convection AND those packs are expected to last 10+ years AND they have to cope with extreme environmental conditions which can ONLY be done with active heating and cooling.

The average ebike doesn't expect any of the above so a thermally-unmanaged pack is acceptable.

In the future cells might more tolerant of high & low temperatures and have such a low IR they don't generate meaningful heat when charged/discharged and so not require thermal management. I think we all look forward to those 1000Wh/kg, $10/KWh, 50 year lifespan cells 8)