BQ28Z610: The calculation of Battery's SOH(State-of-Health)

Roger CH Chang

Part Number: BQ28Z610

Hello,

BQ28Z610 was applied to our battery pack. After we got the 2pcs failure samples from our customer and it’s looks very strange with “SOH”. Below will showed 3pcs result and these 3 batteries are the same design for us.

Failure-1

This one is new battery pack and use for our customer, the cycle count = 1 , it’s looks the fresh battery pack, SOH we expected to near to 100% but the average of SOH is 40%

Failure-2

This one is new battery pack and use for our customer, the cycle count = 6 , it’s looks the fresh battery pack as well. And the SOH value looks not stable and low.

About the Good sample, and we choose one battery pack and all design parameter is same as above 2 sample. The value of SOH looks very stable.

So, how to explain this abnormal change of SOH? Or is there any way we can reproduce this issue?

thanks

Roger

over 2 years ago

0 Alexander Mazany over 2 years ago

TI__Genius 11770 points

Hello Roger,

Have you seen these two threads?

https://e2e.ti.com/support/power-management-group/power-management/f/power-management-forum/1069239/bq28z610-data-of-soc

https://e2e.ti.com/support/power-management-group/power-management/f/power-management-forum/1076507/bq28z610-battery-rsoc-soh-jump-at-the--10-battery-have-gpcrb

It looks like this is a duplicate thread. SOH is not meant to change very suddenly like this, but pulsed loads at cold temperatures are the most difficult for gauging. Also, have you see Wyatt's suggestion on the second thread? See if you can implement the experiment he suggested in the second thread by changing deltaV to be negative. Also, I believe you should be able to post on the other thread, even if you did not start it. Lets try to keep everything to one thread so it doesn't get confusing.

thanks,

Alex M.

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BQ28Z610: The calculation of Battery's SOH(State-of-Health)