BQ76940: BQ76940 & BQ76930 cell short problem

Qianqian

Part Number: BQ76940

Hello TI Experts，

Now I am using BQ76930/BQ76940 for 16cells 20cells 25cells situation~

I have seen the Configuring Alternative Cell Counts in the datasheet

My problem is that what solution will be better for 16cells 20cells 25cells situation? two BQ76930 for 16cells & 20cells? two BQ76940 for 25cells?

If on the battery side,the distance is different betwen cells~

for example, when it's 20cells, cell6 and cell7's distance is much longer than cell7 and cell8, I want to short cell6 and cell7 to reduce loss,Is it OK to do that? but it will be different from the cell configuration according to the datasheet,

over 7 years ago

0 David Hien over 7 years ago

TI__Genius 10830 points

Hi Fawn,
Thank you for your interest in our products. A BMS expert has been assigned to your question.

Regards,
David

0 -Terry over 7 years ago

TI__Expert 5090 points

Hi Fawn,

I would stick with the recommendation as described in the datasheet to be safe. While an alternate configuration might work, that hasn't been as thoroughly tested as what is shown.

Thanks,

Terry

0 -Terry over 7 years ago in reply to -Terry

TI__Expert 5090 points

Regarding your other questions, for a 16S-20S system, you can consider two bq76930, with each configured as described for an 8S system. For a 25S system, you can consider a bq76940+bq76930. You might look at www.ti.com/.../tiduc43a.pdf for an example 20S design using two bq76930.

Thanks,

Terry

0 Qianqian over 7 years ago in reply to -Terry

Genius 5010 points

Hi Terry,
Thanks for your reply~
Another question,For 25S system, Which is better? two BQ76940 13+ 12 ; or BQ76930+BQ76940 10+15?

0 WM5295 over 7 years ago in reply to Qianqian

TI__Guru 54715 points

Hi Fawn,
The 2 bq76940 implementation would allow 6 thermistors vs 5 on the bq76940 with bq76930. The bq76930 should save some part cost but require a separate inventory item. From a performance standpoint it should not matter, which is better may depend on logistics and the design need.

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BQ76940: BQ76940 & BQ76930 cell short problem