Recently Padre released a small battery solution, 3 mm rechargeable lithium polymer battery.
It’s not big problem actually for most lipo batteries to work with 3mm thickness, but for small size ones, it can always be problem because of the PCM(protection circuit module), the PCM itself always has thickness of about 3mm, if the size is big enough, the whole battery can have only 3 mm thickness, but what about the small size batteries? such as the PD301220, the length and width is 12mm and 20mm, the width is too narrow to place all parts of the PCM, the PCM must be folded, hence the thickness will for sure be more than 3mm, always 3.5mm, but this is not accepted by many engineers who require max thickness of only 3mm.
Padre offered new solutions and made it under 3 mm with a small size lithium polymer battery PD301220, but another problem is involved, the length can be 2 mm longer than normal ones. the lipo battery final size with PCM is 3.0mm x 12.5mm x25mm.