BYD's 'blade' battery, will it be afraid of cold?

Lithium iron phosphate batteries may cause thermal runaway when it exceeds 600°C, and thermal runaway of a single cell will not easily lead to the destruction of the entire battery pack, and lithium iron phosphate batteries are more resistant to cyclic charging. Therefore, today, lithium iron phosphate batteries have ushered in the second spring, the top and runner-up of electric vehicle sales-Hongguang MINIEV and domestic Tesla Model 3 all use lithium iron phosphate batteries, and BYD's 'blade' battery has become It is a star in the field of lithium iron phosphate batteries, but even an excellent battery such as a 'blade' battery also has to face the common problem of lithium iron phosphate batteries-fear of cold. BYD's 'blade' battery has solved the shortcomings of low energy density of lithium iron phosphate batteries by optimizing the battery pack structure, but is it still afraid of cold? For a long time, the battery life of lithium iron phosphate batteries has been seriously attenuated in winter, which makes many electric vehicle owners miserable. In fact, the safety and cold tolerance of lithium iron phosphate batteries are determined by the chemical characteristics of lithium iron phosphate. Today we abandon technical terminology and tell everyone the mystery. In a lithium-ion battery, the positive electrode material of the battery is like a cage with lithium ions. When discharging, the electrons on the lithium atoms nested on the graphite of the negative electrode are snatched away, and the positive electrode material grabs the lithium ions and locks them in, and waits until charging. Release it when it's time. Cathode materials such as lithium iron phosphate and ternary lithium are all cages, but the characteristics of the cage are different. The ternary lithium material treats lithium ions wide in and out, which makes it easier for ternary lithium-ion batteries to achieve high voltage and high power. In addition, the same weight of ternary lithium material can hold more lithium, which makes the energy density of ternary lithium-ion batteries higher. However, the cage of the ternary lithium material is not strong and will disintegrate at high temperature and release oxygen. The reason why the spontaneous combustion reaction of the ternary lithium ion battery is so violent is because the ternary lithium material collapses and releases oxygen to form a positive reaction. promote. The cage of lithium iron phosphate is very strong, not easy to disintegrate at high temperature, and has a longer life than ternary lithium materials. However, the lithium ion is strictly in and out, and the voltage/power of the battery is not easy to increase, especially in the low temperature environment. It is more difficult to get out of the cage of lithium iron phosphate material, which is the reason why lithium iron phosphate batteries are seriously attenuated in winter. Understand the principle, it is estimated that everyone knows how to improve the winter endurance performance of lithium iron phosphate batteries, that's right! heating. There are a lot of ways to heat lithium iron phosphate batteries. The simpler and rude methods are as follows: A new car maker directly arranged a small 'diesel water heater' for the battery pack, using burning diesel as the method. The heat source heats the battery, but as a new energy vehicle, such a measure is really a bit spicy. Today, with the rapid development of new energy vehicles, the means to 'warm up' lithium iron phosphate batteries are constantly being improved. For example, the outer layer of the battery cell of BYD blade battery is wrapped with insulation material, and the inside of the insulation material is a thermal management system. Such a structure can further reduce the power loss caused by battery heating. According to official data, BYD blade battery packs can guarantee normal use at -10°C. But is this really the case? Autohome 2020 electric vehicle winter endurance test has been completed. It is said that several models using lithium iron phosphate batteries have good performance (for specific test details, please pay attention to Autohome New Energy Channel New Energy Winter Hengping launched in January ). Disclaimer: Some pictures and content of articles published on this site are from the Internet. If there is any infringement, please contact to delete.