For counterfeit emergency start power products, the virtual protection circuit is tantamount to murder, especially for the multiplying battery used in emergency start power supplies. The fraud of the protection circuit accounts for about 3-5% of the product cost. Unfortunately, it is not obvious from the appearance. Whether or not to protect the circuit, you can only rely on the conscience of the business, so try to buy a big brand.

　　In the process of using lithium-ion batteries or lithium battery packs, in order to avoid the user's wrong operation and cause the battery to heat up, the decomposition of the electrolyte in the battery will generate gas and increase the internal pressure, resulting in the precipitation of metal lithium, etc., causing fire and For various reasons such as the risk of battery rupture and the deterioration of battery characteristics due to over-discharge, a protection circuit must be used in the lithium-ion battery circuit.

　　The protection of lithium-ion rechargeable batteries must have the following 4 protection functions to ensure the safety and reliability of the battery.

　　Overcharge protection, to prevent the battery from exceeding the battery's charging limit voltage when charging, and the battery is overcharged, which can easily lead to the deterioration of the battery's characteristics, fire and rupture, ensuring safety.

　　Over-discharge protection prevents the battery from exceeding the battery discharge limit voltage when the battery is discharged. Over-discharge of the battery will directly lead to the deterioration of the internal electrochemical performance of the battery, which will affect the service life of the battery, and the battery will be scrapped.

　　Over-current protection prevents damage to the MOSFET, allowing the battery to be safely charged within the maximum charging current value it can withstand.

　　Short circuit protection, to prevent the battery from catching fire and explosion due to careless operation, directly connecting the positive and negative poles, to ensure the safety of use and transportation.

　　Therefore, for the fake protection circuit of emergency start power products, it is tantamount to murder. Especially for the multiplying battery used in emergency start power, the fraud of the protection circuit accounts for about 3-5% of the product cost, but unfortunately it is not visible from the appearance. Whether there is a protection circuit or not can only be based on the conscience of the business, so try to buy a big brand.