Why does a battery fail?
To understand why a battery fails, first, we have to look at different types of battery failure.
The first type is the predictable type, where we know that there is a design flaw involved either in the electrode, separator, or processes.
The second type is the more difficult type of failure, which is the random failure. It is hard for us to trace back to a design flaw for this type of failure. The cause of this type of failure usually is due to stress event such as charging at sub-freezing temperature or vibration.
So why does a battery fail?
Well, the first reason is always because of incorrect uses. For example, Lead-acid and Li-ion battery cannot be fully discharged and must be stored with a remaining charge.
Harsh environments can also cause batteries to malfunction. The heat combined with a full charge can induce more stress on Li-ion and may cause it to explode.