How to measure battery voltage?

[mun35]

Hi

My phone has refused to switch on and I've tried all the possible button combinations. Charging it heats up, but neither the screen or LED come on. I hope it's just a battery issue so I've taken it apart. However, the battery connector appears to have several copper contacts. To measure the voltage, which contacts are the positive and negative terminals?

Any advice appreciated.

TIA

 

[Rukbat]

They should be marked on the battery, where the wires go in. If not, try the red and black - that's the standard, but not everyone sticks to the standards.