1. Using air as a medium: Air heat dissipation means that air sweeps across the surface of the battery to take away the heat from the surface of the battery. According to the cause of wind, it is divided into natural convection and forced convection. The wind formed naturally by the speed of the vehicle is natural convection, and the forced wind generated by fans such as fans is forced convection. The ventilation methods are divided into parallel and serial. Many researchers have found that parallel heat dissipation and ventilation methods are better, but the heat dissipation effect is also affected by the width of the runner. Due to the limited space of the car and considering the cost, air heat dissipation is the most widely used. Based on air heat dissipation, people have studied the effect of parallel heat dissipation, and designed various arrangements of battery packs. In order to improve the heat dissipation performance of the wind, the wind baffle is designed and improved, the air duct is widened, and the heat dissipation effect is improved. Air heat dissipation costs are low and the structure is simple, but it is not so effective. When the battery discharge reaches a certain level and the external environment is high, even if the wind speed is increased, the battery temperature cannot continue to drop.
2. Use high and low temperature resistant battery materials, including electrodes, electrolyte materials, etc. This is a method based on the internal materials of the battery: the battery undergoes a chemical reaction, and the heat-generating components are mainly positive and negative electrodes, electrolytes, etc., so the performance of these materials is studied And make improvements to increase its temperature activity range. For the electrode material, the key is to improve its thermal conductivity, so that the heat generated inside the battery can be released in time, so as not to accumulate inside the battery and damage the battery. In order to improve the thermal conductivity of the electrode, copper and aluminum are added to the electrode carbon material. By improving the thermal stability of battery materials, the battery capacity is generally reduced, but the battery capacity is an important indicator of the battery. Therefore, improving the overall thermal performance of the battery by improving the thermal performance of the battery material has certain limitations.
3. Use phase change material as the medium: when the phase change material undergoes phase change, it can absorb and release a large amount of heat, but its own temperature change is not large. The phase change material can directly contact the battery and has a simple structure. Highlight its advantages. The phase change material is highly efficient and feasible, simple in structure, and does not require additional energy consumption, but its low thermal conductivity will cause the dissolution state of the phase change material to vary greatly where it is in contact with high and low temperature batteries, thereby reducing heat dissipation performance. The application of phase change materials for battery thermal management is the main development direction in the future.
4. Using liquid as a medium: The liquid cooling effect is stronger than air cooling, but the structure is more complicated, because many liquids cannot directly contact the battery, and the liquid needs to be wrapped, pipes are arranged between the batteries, and jackets are set; but it can be with the battery Liquids in direct contact generally have poor flow properties and poor heat transfer effects. Heat pipe technology can also be called a kind of liquid heat dissipation. It depends on the phase change of the medium in the pipe, which will be accompanied by heat absorption and exotherm. The phase change is mainly the change between liquid and gas, which is a kind of efficient exchange. The application of thermal components in battery thermal management is also getting more and more attention.