Infrared camera can help to analyze a battery problem

Checking the battery pack with an Infrared camera can help to detect a problem with the battery performance. This above picture shows that one set of cells has a serious over heating problem. The temperature reaches to 40*C while the ambient temperature is just 19*C. It seems the problem has to do with the bus-bar connecting the cells and the DC power cable that is laying above these cells.  Early analysis of the problem can save the battery pack from a damage.