_What is a blade battery? First of all, to correct a misunderstanding, some people think that blade batteries are a new type, different from ternary lithium batteries and lithium iron phosphate batteries. In fact, the "blade" is just the shape of a single battery, and the essence is still a lithium iron phosphate battery. The blade battery "flattens" a single battery cell. After the width is stretched, the thickness becomes thinner, and the length, width and height are reduced to: 960mm*90mm*13.5mm. The inside of the battery pack is distributed from top to bottom with insulation cotton, thermal management modules, insulation materials, etc., and the outside is the battery case. There is also a water-cooling heat sink and a strength mechanism to support the battery inside. Traditionally, cylindrical single cells are used. After stacking, many gaps will be formed. Apart from supporting cooling and supporting components, the final space utilization rate can only reach more than 40%. The flat blade battery can reduce the ineffective gaps between single cells, and the increase in area also plays a great role in heat dissipation. After the overall arrangement, the space utilization of the blade battery is as high as 60%.
_Acupuncture test BYD selected the two most popular batteries for pure electric vehicles as test comparison objects, namely ternary lithium batteries and lithium iron phosphate batteries. Among the three, the performance of the ternary lithium battery was the most tragic. After the steel needle was pierced, the eggs on the battery were blown away. The battery itself burned violently, and the surface temperature exceeded 500°C. Regular lithium iron phosphate block batteries performed slightly better. Although the temperature also rose to 200~400°C and the eggs were burnt, there was no open flame, only a little smoke. The blade battery performed best in this experiment. The shape of the egg has not changed much with the naked eye. The battery has neither open flame explosion nor smoke. The surface temperature is controlled between 30~60°C.
_Advantages of blade batteries 1. The energy density of the battery per unit volume is increased, which is more than 1/3 higher than that of traditional batteries. 2. Material costs are reduced by about 1/4, including materials and human resources. 3. The battery is small in size and can bring better space performance to the vehicle. 4. The battery is light in weight and consumes less energy to overcome its own resistance, further increasing the battery life. 5. Better safety performance. Under high temperature, overcharge, extrusion, acupuncture, etc., the probability of battery cores catching fire and exploding is reduced.
_Disadvantages of blade batteries 1. Poor charging and discharging performance under low temperature conditions. This is an "occupational disease" of lithium iron phosphate, and the battery power will be greatly reduced in cold conditions in winter. The lower temperature limit of lithium iron phosphate is -20°C, while ternary lithium batteries can reach -30°C. The low temperature attenuation of ternary lithium is about 10, and that of lithium iron phosphate reaches 20. 2. It is difficult to repair the battery after being collided. Because the blade battery eliminates the need for a structure to support the battery cells, it uses each battery cell itself as a bracket. Under external impact, it is difficult to ensure the integrity of the battery core. If one cell is damaged, other cells connected in series will also be affected.
_Blade Battery Questions and Controversies At that time, the "Han" model of Blade Battery had not yet been launched, and everything remained at the level of slogans, which already caused BYD's market value to skyrocket by nearly 14%. There is a particularly prominent article that comprehensively criticizes BYD's "liar" behavior. If you are interested, you can search it by yourself. The views are summarized as follows: 1. BYD’s battery technology innovation does not involve battery electrodes or other important components. 2. The density of the blade battery increases, which actually secretly increases the battery volume and puts in more battery packs. 3. The decay characteristics of lithium iron phosphate have not been solved in any way, and the decay rate is 100km per year.
4. BYD’s patent on blade technology is tricky because it takes a long time to apply for a patent, but BYD only took one year.
... The article made a lengthy criticism and suspicion of BYD. I dare not say whether it hit the mark on a few points, but at least there was a lot of bias in the words. For this reason, BYD also specifically clarified this question. The blade battery is BYD’s declaration of war to return to the battlefield. After 2017, BYD was overtaken by CATL and lost its status as the leading domestic battery company. The lithium iron phosphate battery that BYD has always insisted on has been squeezed by the high energy density and low price of ternary lithium batteries. The "blade battery" we hear now is actually the "super battery" plan proposed by BYD in 2019. The Ningde era has opened an era, but can BYD end it? In a war without gunpowder, winning and losing are all silent under the undercurrent, and the sieve of the market will deliver the final answer.