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Discussion Starter · #1 ·
Hello all,
I have kia soul HV battery pack with around 7 damaged cells in random modules.
Like on attachment Kia has 8 modules and 192 cells (96 parallel pair) . 4 modules 10S2P and 4 modules 14S2P
Until I get all 192cells new I have 2 options to choose :
1. Disassembly one module to get good cells for the rest modules and create one new module 126Ah
2. Disassembly of two modules to get good cells for the rest modules and create two new modules 63Ah

The original capacity of modules drops over the years, and the pack has a different capacity now around 40Ah.

Personally, I think second option 2 is better when connecting different capacity modules in series, but in this option, I will use the only 10S1P per pack not 10S2P like in original module

ORIGINAL PACK 75Ah modules :
122975


Option 1 : --------------------------------------------- Option 2 :

122976
122977
 

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I wished I got answers to this.
Is it possible to work on those cells of the modules that way? I learnt the Kia/Hyundai packs are lithium polymer packs compromised of gel like electrolyte. So how do you want to get the repairs done?
 

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Discussion Starter · #3 ·
I wished I got answers to this.
Soon I will get new cells. Probably before someone will answer me I will test it myself.

I think a lots depends on BMS system and how it will react that one or two modules will have longer more energy than other modules of battery. I see that for now it is always trying to achieve the same voltage for all cells, so logically thinking it is better to connect in Option 2 which won't make not so big capacity difference compared to the rest of modules and won't be big difference in voltage to equal with other cells. Just need to test also internal resistance of the original cells and new but anyway it will be 2 new modules, not different single cells in the module.
 

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I don't think either option will work in the car with the factory BMS.
The BMS is going to fault and open contactors if you change the number of cells in series (96s).

It will also fault and open contactors if the voltage difference from the highest the lowest cell is too great. I don't know what the threshold for that delta is on your specific car, but I'd guess 0.3 volts. If you have some portion of the pack with less capacity, that capacity will be used up sooner and you will hit that delta voltage spec, fault, and open the contactors.
 

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I don't think either option will work in the car with the factory BMS.
The BMS is going to fault and open contactors if you change the number of cells in series (96s).

It will also fault and open contactors if the voltage difference from the highest the lowest cell is too great. I don't know what the threshold for that delta is on your specific car, but I'd guess 0.3 volts. If you have some portion of the pack with less capacity, that capacity will be used up sooner and you will hit that delta voltage spec, fault, and open the contactors.
This is similar to what's obtainable with Toyota's NIMH module blocks in a pack. The 0.3 Delta between blocks of modules.
 

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Discussion Starter · #6 ·
I agree, in my car delta is 0,4 V Voltage difference but between cells not modules
 
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