ONE. Definition
Battery capacity: refers to the total amount of charge that a battery can hold, usually in ampere-hours (Ah) or milliampere-hours (mAh). It represents the capacity of the battery to store electrical energy inside and is an essential property of the battery. For example, a mobile phone battery with a capacity of 3000mAh can theoretically discharge for 1 hour if it is discharged with a current of 3000mA.
Rated capacity: refers to the minimum capacity that should be released by the battery under specified conditions (such as temperature, discharge rate, etc.). This is a commitment by the manufacturer to the battery‘s performance, indicating the minimum amount of power that consumers can expect from the battery under certain test conditions. For example, a brand of battery is labeled with a rated capacity of 2900mAh, which means that under standard test conditions, the battery can emit at least 2900mAh of electricity.
TWO. Influencing factors
1. Battery capacity
① Electrode material and quality: Different electrode materials have different electrochemical activity and can store different amounts of electricity. For example, lithium batteries use lithium metal or lithium alloy as a negative electrode material, which has better electrochemical performance and can store more electricity than traditional lead-acid batteries. And the quality of the electrode material is also critical, high quality electrode material can give full play to its potential to store electricity.
(2) The volume and structural design of the battery: in general, the larger volume of the battery can accommodate more electrode materials and electrolytes, thus having a larger battery capacity. At the same time, the internal structural design of the battery, such as the arrangement of the plate and the distribution of the electrolyte, will also affect the battery capacity. For example, a battery with a winding structure may have a different capacity performance at the same volume compared to a laminated structure.
2. Rated capacity
① Test standards and environment: The rated capacity is determined based on specific test standards. Different countries and industry groups may have different standards. For example, at room temperature (25 ° C), a discharge test at a discharge rate of 0.2C (C is the nominal capacity ratio of the battery) may be defined as the rated capacity. If the test temperature changes or the discharge rate changes, the value of the rated capacity may be affected.
Aging and use of the battery: the battery will age during use, and the chemical substances inside it will undergo irreversible changes, resulting in a decrease in battery capacity. Even if the new battery is not operated in accordance with the prescribed charging and discharging mode in the early days of use, such as overcharging, excessive discharge, etc., it will affect the actual rated capacity it can achieve.
THREE. the significance of practical application
1. Battery capacity: For users, the battery capacity intuitively reflects the approximate use time of the device after a charge. For example, when choosing a mobile power supply, users will judge whether they can meet the demand according to the battery capacity of the device they need to charge and the battery capacity of the mobile power supply itself. If the mobile phone battery capacity is 3000mAh, and the mobile power battery capacity is 10000mAh, in an ideal situation, the mobile power can charge the mobile phone about three times.
2. Rated capacity: It is mainly used for consumers to compare the performance of different brands and models of batteries. Consumers can understand the basic performance of the battery under normal use through the rated capacity, and when the battery does not reach the rated capacity standard, it can be used as the basis for rights protection. For example, if the actual capacity of the new battery purchased is significantly lower than the rated capacity, consumers can ask the manufacturer to provide after-sales service or replace the product.
