jonescg
100 MW
Hi guys,
I have been building LiPo packs from individual cells for a couple of years now, and I believe I have a solid system. I can discharge my 15 Ah packs at 13C and they don't get warm until the last ~25% of the discharge. Now, I have generally not found them to get particularly hot, but I certainly wouldn't be putting it on a 25 amp charger and hammering them again for another 13C hit. Most of the time my ebike would barely tickle 7C, and more like 2C constant.
My race bike will be different - I'm expecting to draw 200 A peaks from my 15 Ah pack - 13C is about 120 kW, but I can't see me needing more than 60 kW from the pack most of the time. I fully expect my pack to get warm, but I can't see it being too hot.
So what if you DID want to hit them really hard? What kind of thermal management would you build into them? I don't mean bunging a thermister on the BMS, I mean active cooling, liquid loops, forced air and the like. Applications include drag racing, circuit racing and flight.
I wanted to start this thread to explore the possibility of active cell cooling designs. Essential criteria includes:
- electrically isolated
- weatherproof
- extremely space and weight efficient
- not too complicated or expensive
I'll start with thin aluminium plates between each cell, or couple of cells to serve as a heatsink. These would have a protrusion serving as a radiator, so during and after discharge convection or forced air could soak the heat out of the pack. I don't know what the electrical isolation would be like though - aluminium tends to chafe cells and short :?
How would you ensure the pack is free from moisture ingress?
Lets throw some ideas around!
I have been building LiPo packs from individual cells for a couple of years now, and I believe I have a solid system. I can discharge my 15 Ah packs at 13C and they don't get warm until the last ~25% of the discharge. Now, I have generally not found them to get particularly hot, but I certainly wouldn't be putting it on a 25 amp charger and hammering them again for another 13C hit. Most of the time my ebike would barely tickle 7C, and more like 2C constant.
My race bike will be different - I'm expecting to draw 200 A peaks from my 15 Ah pack - 13C is about 120 kW, but I can't see me needing more than 60 kW from the pack most of the time. I fully expect my pack to get warm, but I can't see it being too hot.
So what if you DID want to hit them really hard? What kind of thermal management would you build into them? I don't mean bunging a thermister on the BMS, I mean active cooling, liquid loops, forced air and the like. Applications include drag racing, circuit racing and flight.
I wanted to start this thread to explore the possibility of active cell cooling designs. Essential criteria includes:
- electrically isolated
- weatherproof
- extremely space and weight efficient
- not too complicated or expensive
I'll start with thin aluminium plates between each cell, or couple of cells to serve as a heatsink. These would have a protrusion serving as a radiator, so during and after discharge convection or forced air could soak the heat out of the pack. I don't know what the electrical isolation would be like though - aluminium tends to chafe cells and short :?
How would you ensure the pack is free from moisture ingress?
Lets throw some ideas around!