Answer: Each battery has the capability of electrochemical conversion, that is, the stored chemical energy is directly converted into electrical energy. As far as a secondary battery (also called a battery) (another term is also called a rechargeable portable battery), In the process, chemical energy is converted into electrical energy; in the charging process, electrical energy is converted into chemical energy again. This process can be charged and discharged more than 500 times, depending on the electrochemical system.