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Discussion Starter #1
Hi all,

I'm specifying an EV conversion at the moment but struggling to find any details on the Leaf 30kWh cells. Specifically I'm looking for their C ratings for charging and discharging. I've been searching this forum to no avail.

Cheers,

Jonny
 

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Hi all,

I'm specifying an EV conversion at the moment but struggling to find any details on the Leaf 30kWh cells. Specifically I'm looking for their C ratings for charging and discharging. I've been searching this forum to no avail.

Cheers,

Jonny
The number I have seen cited for Leaf modules is 240A continuous, 540A peak, which is somewhat inconsistent with the 5C discharge rate given 33Ah cell capacity (Gen1).

I have also not seen any official docs from Nissan, but there is a way to calculate some stuff from the EPA test reports.
https://www.energy.gov/sites/prod/files/2015/01/f19/fact2013nissanleaf.pdf

According to that doc, measured peak draw was at 87.1kW. Given nominal pack voltage of 364.8v, their current draw would be 238.8A. Since the entire pack is organized as 96s2p, that means 119A per cell.

Now this particular spec sheet didn't specify manufacturer's goals, but I've seen in similar reports continuous and max kW rating numbers as well, which would be more towards the actual specs than what they got from testing. You may find those additional reports for different year models, especially for the 30kW version.
 

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I have also not seen any official docs from Nissan, but there is a way to calculate some stuff from the EPA test reports.
https://www.energy.gov/sites/prod/files/2015/01/f19/fact2013nissanleaf.pdf

According to that doc, measured peak draw was at 87.1kW. Given nominal pack voltage of 364.8v, their current draw would be 238.8A. Since the entire pack is organized as 96s2p, that means 119A per cell.

Now this particular spec sheet didn't specify manufacturer's goals, but I've seen in similar reports continuous and max kW rating numbers as well, which would be more towards the actual specs than what they got from testing. You may find those additional reports for different year models, especially for the 30kW version.
The test peak power would have been limited by the controller's programming, which limits the inverter to driving the motor at no more than 80 kW output... perhaps to protect the battery, but it doesn't really indicate the battery's limit.
 

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Discussion Starter #4
Thanks for the replies. I have found something useful:

https://www.energy.gov/sites/prod/files/2015/01/f19/batteryLeaf5045.pdf

I'm really looking to see what peak power I can squeeze out of these cells in ~100s2p. Obviously planning to implement individual module thermal monitoring and if I can fit it in the space, active cooling. I'm not hugely worried about stressing the pack.

It would be fantastic if I could get near 300kW, but anything above 200kW should be intense in a Micra.
 

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Thanks for the replies. I have found something useful:

https://www.energy.gov/sites/prod/files/2015/01/f19/batteryLeaf5045.pdf

I'm really looking to see what peak power I can squeeze out of these cells in ~100s2p. Obviously planning to implement individual module thermal monitoring and if I can fit it in the space, active cooling. I'm not hugely worried about stressing the pack.

It would be fantastic if I could get near 300kW, but anything above 200kW should be intense in a Micra.
Yeah, I saw that report as well, and it wasn't as informative as the others I've researched. Here is one for example :

https://www.energy.gov/sites/prod/files/2015/02/f19/batteryC-Max3817.pdf

Figure 4 shows the battery’s 10-second charge and discharge pulse power capabilities as a function of
energy discharged. The Medium PHEV battery target performance goals of 37 kW discharge power and
25 kW charge power
So that's basically peak discharge.

In general, Leaf modules are probably not the best choice if you're planning to push them and even thinking about cooling. Volt or other modules prewired for active cooling might be easier to work with.

Your target numbers, such as 200kW, sound way too high.
 

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Above 70% DoD, the leaf battery report shows that they will provide at least 200 kW for a 30-second discharge pulse. i would want to see (or test one first) the thermal data before the flogging really begins.
 

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Yes agreed the Volt battery would be a better choice! Unfortunately in the UK, we seem to have very limited options. Very few Volts have been sold here. Most of our EV sales seem to be the Leaf or battery-leased Zoe's. I will look out for kia Soul EV packs, however my cheapest option by a fair margin is going to be a 30kWh Leaf battery.

I am probably being to optimistic regarding peak current for these cells. Realistically I would never want to pull 200kW for more than 20 seconds. The requirements for the project was to be able to do this in short bursts and not maintain these highs. I would definitely implement battery-temperature and SoC relative power limiting.
 

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Yes agreed the Volt battery would be a better choice! Unfortunately in the UK, we seem to have very limited options.
Well, Volt was just a handy example. Another route could be to go with smaller cells, but more of them in parallel to achieve higher discharge currents. Take a look at BMW i3 packs for example. Also BMW uses air for thermal management.
 

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BMW uses liquid cooling (cooling bottom of the modules)

if you want high power, look at PHEV models, like from VW, they come mounted on a chillplate that's easely usable also.

most PHEV batteries are rated for about 10C

if you want air cooled you can loof for Ford C-Max phev
 
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