What causes the loss of battery energy

　　In a chemical battery, the direct conversion of chemical energy into electrical energy is the result of spontaneous oxidation, restoration and other chemical reactions inside the battery, which are carried out on two electrodes respectively. The negative active material is composed of restoring agent with negative potential and stability in electrolyte, such as living metals such as zinc, cadmium, lead, hydrogen or hydrocarbons, etc.

　　The positive active substance is composed of oxidants with positive potential and stable in the electrolyte, such as manganese dioxide, lead dioxide, nickel oxide and other metal oxides, oxygen or air, halogen and its salts, oxyacid and its salts, etc. Electrolytes are materials with outstanding ionic conductivity, such as aqueous solutions of acids, bases and salts, organic or inorganic nonaqueous solutions, molten salts or solid electrolytes. When the external circuit is disconnected, although there is a potential difference (open circuit voltage) between the north and south poles, there is no current, and the chemical energy stored in the battery is not converted into electrical energy.

　　When the external circuit is closed, a current flows through the external circuit under the action of the potential difference between the two electrodes. At the same time, in the battery, because there are no free electrons in the electrolyte, the transfer of charge must be accompanied by the oxidation or recovery reaction of the interface between the north and south polar active substances and the electrolyte, as well as the material removal of the reverberant and the reverberant products. The transfer of charge in the electrolyte is also completed by the migration of ions. Therefore, the normal charge transfer and material transfer process inside the battery is a necessary condition to ensure the normal output of electric energy. During charging, the direction of electric and mass transfer process inside the battery is just opposite to that of discharge; The electrode reaction must be reversible to ensure the normal process of reverse mass transfer and electricity transfer.

　　Therefore, reversible electrode reaction is a necessary condition for the battery. G is Gibbs reaction free energy increment (joule); F is Faraday constant=96500 storehouse=26.8 A · h; N is the equivalent number of battery response.

　　This is the fundamental thermodynamic relationship between the battery electromotive force and the battery response, and also the fundamental thermodynamic equation for calculating the battery energy conversion power. In fact, when the current flows through the electrode, the electrode potential will violate the electrode potential of thermodynamic equilibrium, which is called polarization. The greater the current density (the current passing through the unit electrode area), the more serious the polarization.

　　Polarization is one of the important reasons for battery energy loss. Because the electrolyte data of lithium ion batteries are different, lithium ion batteries are also divided into polymer lithium ion batteries and liquid lithium ion batteries. The positive and negative pole data of polymer lithium ion battery and liquid lithium ion battery are the same, the working principle of the battery is similar, but the electrolyte between them is different. The polymer lithium battery is light, has strong energy storage capacity, good discharge performance, can form various shapes, and has a long life. The electrolyte of polymer lithium battery is solid electrolyte. Compared with the liquid electrolyte of liquid lithium ion battery, polymer lithium battery can form various shapes to improve the specific capacity of the battery.

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