SLK Electronics has a piece on their site about breaking down a DeWalt 36V A123 high-power Li-ion batteries to make your own battery configurations. This (and several other related articles on the site) is gear towards electric model planes, but is obviously applicable to any application.
- Li-ion Life Extension – Link
- HOW TO rebuild a Li-Ion battery pack – Link
- HOW TO – Refilling laptop batteries – Link