Recently, Yiwei Lithium Energy officially released the news that its 46 series large cylindrical battery system was successfully rolled off the pilot line. This is the first domestic battery company to announce the progress of its own 46 series large cylindrical battery system.
However, in the release news, there is no
Performance parameters, such as energy density, volume utilization and other key information. According to the calculation of the project cycle of general battery system development, in the patent search system, we searched all the relevant patents related to battery systems applied by Yiwei Lithium Energy in the past year.
Among them, there is a patent titled “Power Battery Modules and Vehicles” with the authorization announcement number CN 215988999 U. Personal speculation is very close to the 46 large cylindrical battery system scheme actually used by Yiwei Lithium. The core information in the above-mentioned patents is now refined as follows:
▲Schematic diagram in the patent 1
1) There is no detailed description of the specific model of the cell, it may be 4680, it may be 4690, and it may be 46105. If the number of cells shown in the patent is the real number, the 46 series Pack contains a total of 864 cells, and each 48 cells and a serpentine cooling tube form a small block unit.
2) The cell layout and thermal runaway protection scheme are generally very close to Munro’s dismantling of the Tesla 4680 series a while ago. All the positive poles of the cells face upwards, and an explosion-proof valve is provided at the bottom of the cells. The explosion-proof valve corresponds to the round hole on the base plate one by one.
When thermal runaway occurs, the high-heat gas generated by the battery cell is released through the circular hole on the bottom plate, and then released to the outside of the battery pack through the explosion-proof valve installed on the frame. To achieve the purpose of no fire and no explosion in the state of thermal runaway.
In addition, there is a heat shield made of 1-1.5mm phlogopite or muscovite arranged between the positive electrode of the cell and the upper cover of the box. It can effectively prevent the heat of the cell from being quickly transferred to the upper case cover when the thermal runaway is out of control, and slow down or prevent the upper case cover from being broken due to thermal shock.
▲Schematic diagram 2 in the patent
3) Regarding the way of fixing the cylindrical cells in the box, the way described in the patent is quite different from that of Tesla. Tesla’s method is: firstly, two rows of parallel cylindrical cells are first glued to the cooling plate through acrylic resin quick-drying glue, and then the small blocks formed are loaded into the plastic bracket.
According to the module production process described in the Yiwei Lithium Energy Patent, first of all, the fixing of the serpentine cooling pipe depends on the water pipe slot on the bracket as shown in the figure below, and then the cell is clamped into the cell mounting bracket. In the card slot, finally, the thermal conductive structural adhesive is poured to fill the cell and the cell, the gap between the cell and the serpentine cold plate to ensure the fixation of the cell, and at the same time, the heat generated by the thermal runaway of the cell can be transferred out. , to prevent thermal diffusion caused by heat accumulation. If the actual case is as described in the patent, compared with Tesla, Yiwei Lithium Energy has less steps to fix the battery cell and the serpentine cooling plate.
▲Schematic diagram in the patent 3
In addition to applying for the patents described in this article, Yiwei Lithium has also applied for many other patents on the application of 46 series large cylindrical cells, including an interesting patent. Patent name: A cylindrical battery module and battery pack, the patent describes another arrangement of the 46 series of large cylinders in the battery box: laying down, not what we have seen so far, whether it is special or not. Sla is also a vertical arrangement of other homes. The advantage of this is that it can further make more space for the Z-direction avoidance of the entire vehicle.
▲Large cylindrical cells arranged lying down
At present, the development of 46 series large cylindrical cells and battery systems in the industry is in a hot stage. The picture below shows the current situation of domestic and foreign battery companies and car companies deploying large cylindrical batteries.
▲A list of the layout of the large cylindrical battery
With Tesla as the leader in the development and application of 46 series large cylindrical batteries, later followers all rushed to the large cylindrical series to improve group efficiency, reduce the difficulty of BMS control, and can use high nickel and carbon silicon anode materials. The original intention was to develop the 46 series battery system. In the field of typical square-shell batteries, we have seen the domestic battery market in the past three years, and the extreme micro-innovations in system structure, thermal management, and thermal runaway protection solutions among major companies.
Similarly, I have reasons to believe that: with the successive release of 46 series large cylindrical battery system participants products at home and abroad, in the application field of 46 series batteries, although all are 46XX large cylindrical batteries, it should be possible to see different manufacturers in the future. Different 46 series battery cell layout schemes, as well as different 46 series battery system thermal management, thermal runaway protection and structural schemes. Some of Yiwei Lithium’s patents described in this article are just a typical representative of this field.
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