BQ40Z50: Inquiry about BQ40Z50 Application with LiFePO4 Cells

Relly Chu

Part Number: BQ40Z50

Tool/software:

Hi TI Team,

I hope you're doing well. I have a question regarding the BQ40Z50 when used with LiFePO4 cells. I uploaded the charge and discharge settings to the GPC tool, and the GPC report suggested that the best chemistry ID has a maximum deviation of 9.54%. I'm wondering if this deviation would cause significant capacity errors in the entire battery pack (4S8P 32Ah) during charging and discharging.

If it does, are there any ways to improve this? Also, is impedance track less accurate when applied to LiFePO4 batteries?

Looking forward to your advice.

Best regards,

Relly

7 months ago

0 Alan Frias 7 months ago

TI__Mastermind 27405 points

Hello Relly,

This question has been assigned, and we will get back to you soon

Regard,
Alan

0 Alan Frias 7 months ago

TI__Mastermind 27405 points

Hello Relly,

Having a deviation of 9.54% would cause a noticeable, but workable, error in your performance with your pack especially with a higher series pack count. To improve the performance of your system I would closely look for your cell's Chem ID, TI has a big database of cells, but seeing that it wasn't able to find a chemID with a lower DOD than you might need to send in your cells to get added to the database. Another way to improve the accuracy is to verify all your values in the register tab are accurate to your cell datasheet and also doing a calibration in the calibration tab. In term of accuracy of Impedance tracking with LiFePO4 on the BQ40Z50 it is capable of handing the cell chemistry and has a feature of dealing with the cell chemistry.

Techincal reference page 53,
https://www.ti.com/lit/ug/sluua43a/sluua43a.pdf?ts=1739989654286&ref_url=https%253A%252F%252Fwww.ti.com%252Fproduct%252FBQ40Z50

Regards,
Alan

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BQ40Z50: Inquiry about BQ40Z50 Application with LiFePO4 Cells