Answer: The battery capacity is affected by active materials and utilization. The external dimensions of the battery for electric bicycles are fixed, and the quality of the plates has been limited to a certain extent. Only by increasing the utilization rate of active materials can the capacity be increased. To increase the battery capacity, it is necessary to increase the porosity, increase the content of PbO2, and the specific gravity of sulfuric acid, but these measures will accelerate the softening of the positive electrode plate, resulting in accelerated degradation of battery life, and the active material will expand and contract during the charging and discharging process (especially the positive electrode plate) , The deeper the discharge depth, the greater the expansion and contraction of the active material, and the faster the softening of the active material. Therefore, when the initial capacity is too large, it will directly affect the battery charge and discharge times. Of course, to meet the use, the initial capacity must not be too small, and a compromise option is needed to meet the needs, which not only guarantees an extended life, but also ensures that the capacity meets the use requirements.