Hello,
I'm an undergraduate mechanical engineer working on my senior design project. As part of our project, we plan on having 25 3v rechargable button batteries in series (end goal: 75 volts). We do not want to ignite our button batteries, and optimizing the charge time/measuring remaining battery life is outside the scope of our project, so we would be satisfied with safe and repeatable charging (1 chip for charging the entire pack). We need to keep the battery area/volume limited (aaa is ok, no larger, preferably flat batteries). Does anyone have any product recommendations for charging circuitry or alternative designs (dc-dc up converting will kill our battery life too fast)? Thin film batteries are too rich for us. Or is our best bet to avoid lithium altogether? Can we simply apply ~75 volts over the batteries in series If they are not lithium? I watched the 100 minutes of introductory to battery management courses, but want to clarify a few items before moving forward.
Example battery:
http://www.digikey.com/product-detail/en/ML-1220%2FF1BN/P663-ND/2404068
Any advice is greatly appreciated.
Thank you,
DJ