Part Number: BQ34Z100-G1
Dear colleague,
Below is customer description, and attachment is CC file. Could you please give some advice?
Thanks a lot!
1. When the customer's battery in the battery factory, they made the curve change of the battery cell there on July 15. The main change item is the internal resistance of the battery cell.
2. The BMS board at that time was on the battery pack, after the update of internal resistance, through the EV2400, IT_ENABLE command to do a charge and discharge cycle, at the end of the cycle pack voltage is 68V, capacity was about 57 percent. The battery pack has been standing in the workshop, a day later to measure the capacity, the capacity is basically unchanged.
3. After receiving the notice from the end customer, the shipping voltage was changed to 65V. The battery factory first discharge, then charge and then discharged, then charge the battery pack to 65V. And the capacity is about 40%. (The battery will be shipped on July 25th and 26th.)
4. When the battery packs are delivered to the end customer, the capacities becomes about 6% and the voltage remains 65V. Therefore, they coordinated with the end customer and randomly selected 10 groups of the battery pack in the battery factory. When the battery was stationary for one night, one battery pack capacity jumped to the capacity of before charging and discharging.
5. In the battery packs (6%) which delivered to the end customer randomly selected a pack, discharging, and then charge to 65V, capacity shows about 40%.
Questions now:
1. Why does the capacity jump to the capacity of before charging and discharging?
2. At the same time and at different places, why does the capacity of the battery in the end customer's hand jump to the capacity of before charging and discharging, and it is random in the battery factory?
3. After recharging and redischarging again, whether there will be a risk of the capacity jump?
(Please visit the site to view this file)