HV Cell Specifications

Dear all,

Does anyone have any comprehensive data/specifications about the Panasonic/Toyota NP2 cells that we have in the Gen 3 Prius other than what is detailed in this link... Nickel-metal hydride battery | Toyota Battery Corporation, will need translating from Japanese to English of course (unless you understand Japanese).

I'm specifically looking for the discharge rating (usually denoted C rating on LiPo batteries) to mimic a realistic load when testing my cells individually.

I've seen mention that the discharge could be up to 120A? Assuming that's true, and assuming the cells have a nominal capacity now after over 10 years of 6000mAh each (6500mAh when new), and knowing, they are all connected in series so only the voltages multiply. To reach 120A, you'd have a discharge C rating of 20C?

I know the DC/DC boost voltage from battery voltage up to 650V, assuming the 80A remains at the boosted output going into the inverter to feed the motors, this gives 78kW of power. So far, I reckon my maths is right (do call me out with any discrepancies), but I could do with some specs/data of what actually gets sucked from the battery when it goes into the DC/DC and into the inverter. Also charging rate would be cool too.

Basically, I want to load test my cells as closely as possible to what the car would draw in one big hit (i.e standing start from engine off to full speed up to where it will switch over to recharge the battery, but to mimic that 'per' cell as opposed to the battery as a whole.

Finally, if the cells are suspected to be too old because they collapse under load, would the higher internal resistance cause enough heat to boil off of evaporate the electrolyte fluid to the point that the cell would weigh less? Does it work like that? In my head it does, but I'm not sure, maybe there isn't that much electrolyte fluid in there so it's absence wouldn't change the weight enough to notice if it's a bad cell.

I'd love some thought and experiences on this. Thanks, Deian

 

Yes of course. I was just saying it's in Japanese. I translated it that way.

But not much technical replies this time. Sad.