Sony BP71 Li-ion Battery Back Construction Info

* Caution Li-ion Batteries can burn or explode if you abuse them *

This is a Sony PB71 LI ION Battery pack from a Vaio FX203K.
It is rated at 14.4V and 2600Mah.

The battery pack is constructed from eight individual cells which are connected serialy as four pairs.

Here is a diagram of how they are connected.

The cells all connect to the controller PCB which is shown below.

This pack was not charging and upon opening it revealed that six of the eight cells had gone open circuit. This is usually due to the safety fuse going when they get too warm.

If you have any queries about any other battery packs then let me know. Bruce Benson