When it comes to the production of electric cars, one component is increasingly becoming the focus of brand strategists. The battery. Without powerful batteries and a stable supply of energy storage, any business strategy, no matter how sophisticated, is inevitably doomed to failure. In order to counteract this battery fear, the top managers of the German car manufacturers repeat almost like a prayer wheel how secure the contracts with the battery manufacturers are and are also trying with all their might to build battery factories out of the ground. Usually in cooperation with external partners such as CATL or in the case of VW Northvolt.
But a reliable, crisis-proof supply of the most expensive and probably most important element of an electric car can only be guaranteed if you hold the reins of battery production firmly in your hand and don’t have to rely on others. The Chinese carmaker BYD has been implementing this concept of personal responsibility for over 20 years. First with lithium-ion batteries and since 2020 with lithium-iron phosphate accumulators, whose cells are shaped like a blade. Hence the name Blade Battery. The driving force behind energy ingenuity is the FinDreams Institute, which employs more than seven engineers. The research is based on three pillars: (stationary) energy storage, rechargeable batteries for everyday devices and 80 percent automotive batteries.
Near the Chinese city of Bishan, almost 50 kilometers west of the 30 million metropolis of Chongqing, BYD produces the blade batteries on eight lines in a 20 gigawatt factory. A second production facility with a capacity of 15 GWH has already been completed. Even if the production of the cells is largely automated, around 17,000 employees work on the 6.12 square kilometer site.
Blade batteries are produced in eight steps: mixing, coating, pressing, laminating, assembling, drying, high-precision injection of the electrolyte and functional testing of the cell. During the coating, the raw material paste is applied to the copper and aluminum foil, whereby it is crucial that the coating is carried out with high precision. Each cell has 155 layers: 39 anode foils, 38 cathode foils and 78 insulating foils.
After coating, the raw material is heated and this causes it to expand, which means that the cathode sheet has to be rolled twice, as graphite is very pliable. Only one rolling process is required for the anode. The tolerance in this production step is just two microns. After this pressing, the coil is rewound to prepare it for lamination. After coating, the packs go into a 70 meter long oven, where they are dried at 140 to 150 degrees and finally the sensitive energy carriers are cleaned of dust with a vacuum. This process takes 14 days, with the actual production taking only two days. The rest of the time is used for intensive testing. Currently, 9,000 cells are possible per day, working in two shifts six days a week.
Compared to other battery types, the blade batteries are cheaper because only a few rare earths are used. The service life of the blade batteries is also suitable for electromobility: BYB promises that after 120,000 kilometers or 3,000 charging cycles, the batteries should still have 90 percent of their original capacity. Charging is quick: the cells are 70 percent full in around 20 minutes. Another big plus of these batteries is the great stability and safety. The BYD blade cells even survive the rigorous nail test, where a large nail is driven straight through the batteries while conventional energy storage devices burst into flames with a loud bang. The operating temperature between 35 and 55 degrees Celsius also contributes to safety.
With the blade cells, it is also important to pack as much energy as possible into the battery from the available installation space. With a length of almost one meter (96 centimetres), a height of almost nine centimeters and a thickness of just 1.35 centimetres, the blade cells make efficient use of the available installation space. The dimensions may vary slightly depending on the vehicle. The Tesla Model 3 competitor BYD Seal has 172 such blade cells installed in the 82.56 kilowatt hour battery, giving one of the blades a capacity of 0.48 kilowatt hours. With a weight of 560 kilograms, the batteries are also competitive in terms of weight. A single cell weighs 2.6 kilograms, including the electrolyte.
Blade batteries are already becoming a bestseller for BYD. Because China competitor Great Wall Motor, Toyota and Tesla also rely on the blade batteries. The first models from the US carmaker with blade batteries are already rolling off the assembly line in Berlin-Grünheide.
