[brian_]

I have just opened up a Volt battery I bought - it took 8 months to get here
Its got 3 off 3.1 kWh modules and 4 off 2.3 kWh modules - so is that a Mk2 Volt?

Yes, the Volt battery with 7 modules is the second generation (2016+). There are four 12S2P (45 V nominal and 24 cell each, so 48S and 96 cells total) and three 16S2P (60 V nominal and 32 cell each, so another 48S and 96 cells total).

https://media.gm.com/content/dam/Media/microsites/product/Volt_2016/doc/VOLT_BATTERY.pdf

Does that use the same chemistry as the Mk1?? - the cells are at 3.37 volts to 3.39 volts -

Both generations are described by GM as "NMC-LMO". Cell voltage ranges should be very similar between generations.

 

[brian_]

All I know is on a mk2 the pouches are the same but wired different. Might be a cooling plate.

The Mk2 or second generation modules are similar (including the same internal cooling fin design), but the Mk 2 cells have substantially higher capacity, apparently resulting largely from being thicker - Mk1 is 96S3P and Mk2 is 962P, so there are only 2/3rds as many cells in the Mk2, but with higher total capacity.

 

[mons2b]

Ive tried to search but cannot find a answer. What is the short circuit rating of a chevy volt gen 1 battery? I thought two times 225 amp 250v or 500v dc fuses (positive and negative) would be good but now im thinking maybe I am incorrect. In New Zealand we are required to fuse as per the below. If anyone knows what fuse would match these specs I would be grateful. My installation is 3x12s Chevy volt modules in Parallel for a total of 96 cells. My inverter is relatively low powered at a max rating of 120amps input. But the rules are quite specific in the reference to "maximum battery short circuit current. The cable I am using is 184amps continuous rated.

"Overload protection 2.2(5) The electrical systems within an electrically-powered low volume vehicle must have over-current protection devices that: (a) are an appropriate selection for the design of the electrical system; and (b) are mounted as closely as possible to both poles of the power source, but not within a compartment containing venting batteries; and (c) are designed to protect the wiring and electrical components of the electrical drive from over-heating following an over-current situation; and (d) have between 20% and 40% overload capacity, in order to protect the electrical wiring and components of the electrical drive from damage; and (e) are DC-rated for the maximum battery voltage and capable of interrupting the maximum short circuit battery current; and (f) protect all connections to the high-voltage traction battery and motor wiring, which must include ammeter shunt wiring, volt meter wiring, battery management systems, chargers, and heaters; and (g) in the event of deployment, are not likely to cause themselves, or any surrounding components to ignite."

 

[remy_martian]

Notice they are concerned about overheating, not about protecting your inverter. The rules are concerned about fire, not wallet, protection.

Max short circuit is voltage divided by battery impedance. It's really not something you ever want to do to a lithium battery....a lead acid will tolerate it.

Detailed fuse datasheets give that max short circuit current. Finding the battery impedance could be roughly inferred by voltage sag at high current draw.