Legal analysis: It is illegal to sell privately assembled lithium batteries. Small amount and small value are illegal acts in violation of industrial and commercial management regulations, and serious cases may constitute the crime of illegal business operation in criminal law. Because there is no professional equipment for personal assembly to check whether the quality is safe or not, the quality of the protective board is also good or bad. I don't know if the quality said by the merchant is true or not, so it needs to be tested and verified repeatedly with professional equipment. The assembly of lithium batteries requires various accessories, such as nickel plates and various cables. Whether the matching and overcurrent capabilities are appropriate requires professionals to match and measure. No matter how good the battery is assembled incorrectly, it still can't play its best role.

Legal basis: Article 225 of the Criminal Law of People's Republic of China (PRC), in violation of state regulations, commits one of the following illegal business operations, disrupting market order, and if the circumstances are serious, shall be sentenced to fixed-term imprisonment of not more than five years or criminal detention, and shall also, or shall only, be fined not less than one time but not more than five times the illegal income; If the circumstances are especially serious, he shall be sentenced to fixed-term imprisonment of not less than five years, and shall also be fined not less than one time but not more than five times his illegal income or his property shall be confiscated: (1) dealing in franchise, monopoly goods or other commodities whose business is restricted by laws and administrative regulations without permission; (2) buying and selling import and export licenses, import and export certificates of origin and other business licenses or approval documents stipulated by laws and administrative regulations; (three) without the approval of the relevant competent departments of the state, illegally engaged in securities, futures, insurance business, or illegally engaged in fund payment and settlement business; (four) other illegal business activities that seriously disrupt the market order.