Firstly, here are some pictures to help you understand how each cell is connected to the PCB. (excuse the rushed editing)
Here is a close up of a cell.
Main IC
This is a battery from a laptop that broke a few months ago. I shut down the laptop one day and it didn't turn back on again. The status lights on the sides didn't light up either. I took it apart but was unable to pin the cause of the failure on a single area or component. One thing that left me confused was the fact that the battery wasn't outputting any voltage on the + and - pins. (I also tried plugging it into the motherboard and then measuring, but still no luck)
I looked around for some information about this, I wanted to use the battery for a power bank, or something similar. I had this sitting on my shelf for a few months, today I decided to take it apart. When I measured the voltage of the battery cells, all four of them were working fine, and were outputting 4.1V each.
Here are my questions: Why isn't the battery pack outputting 15.2V (as is mentioned on the pack)? How do I get the pack to work? If the controller board is actually broken, then how can I safely use the cells (what voltages for charging, etc)? Could this battery, and the possibly faulty controller board, be the cause of my laptop's death?