My latest battery build

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jonescg
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Joined: Thu, 21 Jan 2010, 23:05
Real Name: Chris Jones
Location: Perth, WA.

My latest battery build

Post by jonescg » Sat, 03 Nov 2018, 11:17

This is a nominal 355 volt, 10 Ah battery built using 5 Ah pouch cells (96s2p). It's for the UWA formula student team's race car. The intention was always to use this battery as the dyno-testing and bench-tuning battery given it's capacity, but if push comes to shove, then can drop it into the car and get rolling.
Pack finished top.jpg
Pack finished top.jpg (264.89 KiB) Viewed 103 times
Pack finished front.jpg
Pack finished front.jpg (251.56 KiB) Viewed 103 times
It's using the 30C LiPo (lithium cobalt oxide) pouch cells I normally use in the race bike, so they are capable of some serious short-lived power. This 25 kg battery is able to deliver 100 kW, albeit briefly.

Being a high voltage battery it has numerous designs built in to make it safer. All four 24s units are physically separated by 4.5 mm thick polycarbonate dividers. Two EV-Power BMS modules manage 12 cells each, and are connected by an IsoSPI comms bus. The centre of the battery is where the main 200 A fuse is located, and it is easily removed for pack service. In the vestibule is all the hardware - main contactor, precharge relay, 50 W, 200 Ohm pre-charge resistor and a negative contactor. There's also a 10 A fuse for the charge circuit. The negative contactor also serves as an isolation point for the charge circuit.

It's not waterproof, but it could be made so. It's also not actively cooled, however you could feasibly put some fans on the top cover and draw any hot air out. Being such low impedance cells, the pack isn't expected to generate a lot of heat under the duty cycles they are likely to put it through.
AEVA National Secretary, WA branch vice-chair

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