Lithium battery for electric vehicles: Let me tell you about the reasons for the decline of lithium battery capacity in winter
Lithium battery for electric vehicles: the reason for the decline of lithium battery capacity in winter
Since lithium batteries entered the market, they have been widely used because of their large capacity, small size, and no pollution to the environment. However, in low temperature environments, lithium battery packs have problems such as low capacity, serious attenuation, and poor cycle rate performance. .
Electric vehicle lithium battery: The operating temperature of traditional lithium ion batteries is between -20 and 55. The discharge capacity of lithium ion batteries at -20 is only about 31.5% of room temperature. However, in aerospace, military and other fields, batteries are required. It works normally at a temperature of -40 or lower, so it is of great significance to improve the low temperature performance of lithium battery packs.
Electric vehicle lithium battery
Electric vehicle lithium battery: In terms of its influencing factors and reasons, it is actually its electrolyte. The electrolyte has a great influence on the low temperature performance of the lithium battery pack. The composition and physical and chemical properties of the electrolyte have an important impact on the low temperature performance of the battery. The problem with cycling at low temperature is that the viscosity of the electrolyte will increase and the ion conduction speed will become slower, resulting in mismatch of electron migration speed in the external circuit, so the battery will be severely polarized and the charge-discharge capacity will drop sharply.
Electric vehicle lithium battery: Especially when charging at low temperature, lithium ions can easily form lithium dendrites on the surface of the negative electrode, resulting in battery failure. The low temperature performance of the electrolyte is closely related to the conductivity of the electrolyte itself. The faster the transfer, the greater the capacity that can be exerted at low temperature, the more free lithium salts in the electrolyte, the more migration numbers, the higher the conductivity, the higher the conductivity, the faster the ion conduction, the smaller the polarization, and the lower the battery temperature. The better the performance, therefore, high electrical conductivity is a necessary condition for good low temperature performance of Li-ion batteries.
Electric vehicle lithium battery: The conductivity of the electrolyte is related to the composition of the electrolyte. Reducing the viscosity of the solvent is one of the ways to improve the conductivity of the electrolyte. The good fluidity of the solvent at low temperature is the guarantee of ion transport. The formed solid electrolyte membrane is also the key to lithium ion conduction, and RSEI is the main impedance of the lithium battery pack at low temperature.
Electric vehicle lithium battery: It is not difficult to analyze that the electrolyte is one of the low temperature characteristics that affect its lithium battery pack, but wherever batteries are used, lithium battery packs are essential, so at low temperatures, we can only use low temperature The battery is a low-temperature lithium battery pack. It can work at -40 degrees, but if it is lower than this temperature, our technology needs to go further. However, everything develops with the advancement of technology, and the future can be expected.
