Other Parts Discussed in Thread: BQ2060, BQ2060A, , GPCCHEM
A brief introduction:
We were more than 10 years making a battery pack with a fuelgauge based on the BQ2060 at the beginning and with its revision BQ2060A nowadays. This is a 10 cell in series of the Ni-Mh cell from saft, now arts energy, VH Cs 3200 XL that is attached.
This battery pack is sold to our client and used in a defibrillator sold all around the world. Since the last two years, our client is returning a number of battery packs, more or less 2%, because when they have a problem that BQ2060A is “hung”. The BQ2060A communicate with the HDQ line but the AC measurements an fuelgauge are stopped. We need to restart, removing the battery supply, the BQ in order to operate again. Their equipment and the battery passed the medical standards, so we do not know why this is happening lately. Is the last year, the returning battery packs increased from 2% to 5% more or less, and in the last few months to 10% or more. Now, a new variable has come to the issue, and the BQ sometimes “hung” and sometimes RESET, so the SOC goes to 0 in the middle of an operation with a patient, so it could be a real problem.
SOLUTION AFTER NOT FIXING THE PROBLEM WITH THE BQ2060A
After doing a lot of test and trying to remove all EMI and EMC problems without success, 6 months ago, we decided to do a new design based on the BQ34Z100-G1. We do all the development and test and manufacture some boards that are working ok. We did all the steps for the consecution of the golgen image and manufactured a preseries of 20 battery packs.
The problem is that, our cell is not in the chemistries, but with your tool, you recommend us one of those that exists. The SOC in discharge is completely accurate, no problem with that. In charge, the problem is that, if we charge about 33% with a SOC of 33% of the cell and keep the cell of the equipment, after an hour, the SOC marks 86%. I suppose because of the VOC curve or something like that. If we charge the battery to 100%, after one month, the battery marks 97% that it is not real, due to self-discharge of the battery, and if we discharge the battery, when it is more or less 40% of SOC, it goes to 0 SOC because it is completely discharge, so the real SOC after the month is around 60% not 97%.
It is impossible to go to the market in that way. So we need urgent help with this. We need to know if there is any parameter that we can change or what have to do to correct this point and to have a good impedance track algorithm with our battery.
