What are the factors that affect the discharge capacity of the battery?

1. The voltage electromotive force (voltage) of the battery refers to the difference between the positive balance electrode potential and the negative balance electrode potential when the battery is open. Its magnitude depends on the chemical reaction in the battery, and has nothing to do with the shape and size of the battery. According to the flow reaction of lead-acid batteries, according to the principle of thermodynamics, the electromotive force of the battery is: where E is the electromotive force of the battery; Ee is the electromotive force when the activity or pressure of all reactants is equal to 1, called standard electromotive force (V); R is The molar gas constant is 8.31J/(Kol); T is the absolute temperature (K); F is the Faraday constant (96500C/mol); n is the number of electrons gained and lost in the electrochemical reaction. The electromotive force is one of the measures of the theoretical output energy of the battery. Provided other conditions are the same, the higher the electromotive force of the battery, the greater the theoretical output energy. 2. The temperature of the battery The internal temperature of the battery has a great influence on its performance, especially for lead-acid batteries, because there is oxygen circulation inside the battery during the charging and discharging process, and the extra heat that appears will increase the temperature, and thus the impact Therefore, when judging the performance of the battery, the influence of temperature should be fully considered. When the temperature rises, the movement speed of the electrolyte increases, and new kinetic energy is obtained. Therefore, the penetration force increases, the resistance of the electrolyte decreases, and the electrochemical reaction strengthens, all of which increase the battery capacity. When the temperature decreases, the viscosity of the electrolyte increases, causing the ion movement to receive greater resistance, reducing the diffusion ability, and it is difficult to penetrate the inside of the electrode plate. The deep active material is not fully utilized due to the lack of acid, resulting in a decrease in capacity. Secondly, the electrolyte resistance increases with the decrease of temperature. As a result, the internal resistance of the battery increases, the voltage drop increases, and the capacity decreases. The amount of change in battery capacity when the temperature changes by 1°C is called the temperature coefficient of capacity. 3. As the discharge current increases, the capacity and terminal voltage of the battery will decrease accordingly. This is because during discharge, the PbO2 and Pb of the positive and negative plates are converted to PbSO4. Because the specific gravity of PbSO4 is small, with the precipitation of PbSO4, the pores of the electrode plates gradually shrink, making it difficult for the sulfuric acid in the container to penetrate, and when the discharge current When it increases, the chemical reaction speed increases, and the speed of PbSO4 blocking the pores also increases. Due to the rapid decrease of the electrolyte concentration in the pores, a large number of active materials inside the plates cannot participate in the chemical reaction, and the actual output capacity of the battery is reduced. 4. Electrolyte concentration In lead-acid batteries, H2SO4 is also a reactant. When the volume is clicked, the concentration of the newly added electrolyte is the newly added reactant. Therefore, within the actual electrolyte concentration range, as the electrolyte concentration changes, As the battery capacity increases, the battery capacity is also increased, especially when the battery capacity is limited by the positive plate when the battery is discharged at a high rate. The rated capacity is also called the guaranteed capacity, which is the minimum capacity value that the battery should discharge under certain discharge conditions according to the standards promulgated by the country or relevant departments. Generally, it usually means that when the temperature is 20℃～25℃, the capacity is overflowed, and after being left for 24 hours, it is discharged at a discharge rate of 10 hours or a current value of 0.1C to its termination voltage (1.75V~1.8V/cell, 2V Battery). When the battery is discharged with a constant current, its capacity (Ah) is equal to the product of the discharge current (A) and its duration (h). Cu003dIt(2.9 If the discharge current is not constant, then the output capacity of the battery is the sum of the product of the different discharge current and its duration. Disclaimer: Some pictures and content of the articles published on this site are from the Internet. If there is any infringement, please contact to delete Previous: How to improve the performance of low-temperature lithium iron phosphate batteries