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Methods and influencing factors of charge discharge heat generation testing
Date: 2025-12-15Read: 0
Charge discharge heat generation testing is an important part of battery performance evaluation, especially in the research and application of lithium-ion batteries and other rechargeable batteries. The charging and discharging process is an inevitable part of battery operation. During the charging process, the battery converts external electrical energy into chemical energy and stores it; During the discharge process, this chemical energy is converted into electrical energy to supply external loads. Due to internal resistance, incomplete chemical reactions, and other factors, heat is generated during the charging and discharging process, and the accumulation of this heat may affect the safety and performance of the battery.
The principle of charge discharge heat generation:
1. Internal resistance heating: There is a certain resistance inside the battery, and when current passes through, heat is generated due to the presence of internal resistance. According to Joule's law (Q=I ² Rt), the amount of heat generated is proportional to the square of the current, internal resistance, and time.
2. Chemical reaction heat: During the charging and discharging process, oxidation-reduction reactions occur inside the battery, which also release or absorb heat. Different types of batteries have different chemical reaction characteristics and generate varying amounts of heat.
3. Phase change heat: Some battery materials may undergo phase changes during charging and discharging, such as transitioning from a solid state to a liquid state or from one crystal structure to another. These phase transitions are also accompanied by the release or absorption of heat.
Charge discharge heat generation testThe method:
1. Sample preparation: Select the battery sample to be tested and ensure that it is under standard environmental conditions (temperature, humidity, etc.).
2. Testing equipment: Use professional testing equipment, such as battery testers, equipped with temperature sensors and data recording systems to monitor real-time changes in battery voltage, current, and temperature.
3. Charge discharge cycle: Charge and discharge the battery according to the preset charging and discharging plan (such as CC-CV charging mode), recording the current, voltage, and temperature at each stage.
4. Data analysis: By analyzing the test data, calculate the heat generation during the charging and discharging process, and evaluate its impact on battery performance.
Factors affecting heat generation during charging and discharging:
1. Battery type: Different types of batteries (such as lithium-ion batteries, nickel hydrogen batteries, lead-acid batteries, etc.) have different characteristics of heat generation during charging and discharging.
2. Charging and discharging rate: A higher charging and discharging rate usually leads to higher internal resistance heating, so it is necessary to control the charging and discharging rate reasonably to reduce the generation of heat.
3. Environmental temperature: Environmental temperature has a significant impact on the thermal management of batteries. Low temperatures can increase internal resistance, while high temperatures may accelerate chemical reactions, thereby affecting heat generation.
4. Battery aging: With the use of the battery, the internal resistance will gradually increase, which will lead to an increase in heat generation during the charging and discharging process, thereby affecting the safety and lifespan of the battery.
The importance of charge discharge heat generation testing:
1. Safety assessment: Excessive temperature may cause thermal runaway of the battery, leading to fire or explosion. Therefore, the safety of the battery under normal usage conditions can be evaluated.
2. Performance optimization: By analyzing the heat generation during the charging and discharging process, shortcomings in battery design can be identified and optimized to improve the overall performance of the battery.
3. Lifecycle prediction: Understanding the thermal management of batteries during charging and discharging processes can help predict their lifespan and reliability, and thus develop reasonable maintenance and replacement strategies.