Lithium battery is classified into lithium ion battery and lithium polymer battery. The electrolyte of lithium ion battery is liquid while lithium polymer battery has solid electrolyte. Thus, lithium ion battery is more unstable than lithium polymer battery and using unqualified battery charger will cause battery explosion. Presently lithium batteries power most of mobile phones, notebooks, digital cameras, etc. Unqualified batteries bought will pose a security threat to us, so please pay attention to following points when purchasing batteries:
 
a. Clear rated capacity. Lithium battery without clear rated capacity mark, e.g. 2200mAh or 4400mAh, may be unqualified cell or recycled battery. There are lots of cheap lithium batteries, which are made of recycled battery or from disassembled battery. These batteries might be cheap but cannot last long. Besides, instable quality will damage electric device or might cause explosion in case improperly used.
 
b. Duration time promised. Duration time refers to continuous time from lithium battery built in device to next recharge. Usually lithium batteries in the market cannot promise duration time for customer, this is because of battery’s instable quality. Cheap batteries have used unqualified battery cells, so their duration time is short.
 
c. With protection circuit. Lithium battery characteristic decides it have to match PCM, which protects lithium battery from over charge, over discharge, short circuit etc. Lithium battery without PCM has danger of deform, leakage, explosion etc. Under intense price competition, every battery pack manufacturer is looking for high cost performance protection circuit, or ignore this device basically, so there is lots of lithium battery with hidden danger of explosion in the market, consumer could not distinguish whether with protection circuit, and it’s best choice for us to purchase from reputable seller.