Study on the heating characteristics of lithium-ion battery discharge cycle

The research on the thermal characteristics of lithium-ion battery discharge cycles is of great significance to the development of battery thermal management systems. This paper uses numerical methods to study the micro-heat characteristics of lithium-ion batteries during the discharge process, and analyzes the change law of the lithium-ion battery discharge cycle (SEI) film and ohmic heat of the solid electrolyte. The results show that the lithium-ion battery is at a high rate. Discharge (>5c), an important part of the thermally generated SEI film is heating the lithium-ion battery; with the progress of the discharge cycle, the SEI on the surface of the positive electrode particles of the lithium-ion battery increases linearly, resulting in the continuous increase of SEI resistance. The higher the temperature of the discharge environment, the faster the SEI of the lithium-ion battery's negative electrode thickens and the faster the capacity drops. 0 Introduction Lithium-ion batteries have the advantages of high specific energy, discharge voltage and good cycle life, and are considered to be one of the best energy storage devices for pure electric vehicles (EV) and hybrid electric vehicles (HEV). The thermal management system is one of the core technologies to ensure the safe operation of high-power lithium-ion battery packs. Excessive temperature will cause the destruction of the electrolyte (SEI) film on the surface of the lithium-ion battery, thereby shortening the service life of the battery, and may cause safety issues such as battery explosion. Therefore, studying the thermal characteristics of lithium-ion batteries under complex operating conditions is the basis for the development of battery thermal control technology, and has important scientific guiding significance for the development of power lithium battery thermal management systems. At present, it is important to study the thermal characteristics of lithium-ion batteries through numerical simulation and experimental analysis. The proposed Conan Doyle proposed Bernardi based on the electrochemical model and battery energy equation. On the basis of domestic and foreign scholars, he developed a thermoelectric coupling model for multi-lithium-ion batteries, and used thermoelectric coupling models to calculate the discharge of lithium batteries at different temperatures. Characteristics, and temperature influence analysis and related parameters on the discharge characteristics of lithium-ion batteries. The temperature of the wound lithium-ion battery is calculated using the thermoelectric coupling model. J.v.azquez-arenas and others used a thermoelectric coupling model to simulate a square lithium-ion battery, studied the influence of battery temperature on its discharge characteristics and lithium ion concentration distribution, and quantitatively analyzed the influence of different heat sources on the battery's calorific value. At present, most researches on the thermal characteristics of lithium-ion batteries use thermoelectric coupling models, while the capacity degradation of lithium-ion batteries is rarely considered. During the charge-discharge cycle of a lithium-ion battery, the negative electrode film will gradually thicken due to deposition, resulting in an increase in the internal resistance of the lithium-ion battery, resulting in a significant increase in the heating rate of the lithium-ion battery. In the thermoelectric coupling model of lithium-ion battery, the cycle attenuation problem is considered, and the influence of temperature on the capacity attenuation of lithium-ion battery is analyzed. However, the model and research results established by this model are only applicable to the specific lithium-ion battery studied by this model, and lack versatility. In this paper, the thermoelectric scale model of the battery is used to consider the influence of the SEI change on the heat production of the battery during the decay process of the battery cycle. A detailed analysis of the heat changes during the cycle of lithium-ion batteries and the influence of temperature on battery life are drawn, and the following conclusions are drawn: 1. During the high-speed discharge of lithium-ion batteries (>5c), the heat that appears in the SEI film is that of lithium-ion batteries. An important part of heat, accounting for more than 14% of the total heat; 2. With the development of the discharge cycle, the negative SEI of the lithium-ion battery gradually thickens, the higher the discharge environment temperature, the faster the SEI rises, and the faster the capacity drops; statement: Some pictures and content of articles published on this site are from the Internet. If there is any infringement, please contact to delete the previous article: Does lithium iron phosphate battery pollute the environment?