BYD's new patent is public, revealing a new design of hexagonal power battery

Existing power batteries, from the perspective of appearance, are mainly cylindrical, square shell and soft pack. Each has its own advantages and disadvantages. However, BYD's latest patent has revealed a new type of "hexagonal" battery.

Cylindrical batteries are the most traditional structure, with good mechanical properties of single cells, mature technology and low cost. However, due to the limitation of the shape, the single cell capacity is low. When multiple cylindrical single cells form a battery pack, the gap is large and the space cannot be well utilized. In addition, the mechanical stability of the battery pack is not enough and it is easily affected by external vibration or impact, resulting in short circuit or open circuit.

Square shell single cell batteries have good stability, but are too large in size, small in surface area, low in heat exchange efficiency, difficult to manage thermally, and the problem of cell expansion is difficult to solve after long-term use.

The soft-pack single cell adopts the lamination process, which has a small internal resistance, can significantly reduce the battery's self-consumption, and has good cycle life and rate characteristics. In addition, the use of aluminum-plastic film reduces the use of structural parts and reduces the weight a lot. However, soft-pack batteries are more difficult to control costs and design battery packs.

Tesla is known for its cylindrical batteries, and you must have heard of its 4680 large cylindrical battery. Square-shell batteries are represented by BYD's blade batteries and CATL's Kirin batteries.

However, judging from a recently published patent, BYD is also promoting the development of cylindrical batteries. In a utility model patent titled "Battery and Battery Module and Battery Pack Having the Same" published on August 5, BYD proposed a hexagonal battery.

As shown in the figure, the battery pack is composed of several regular prismatic battery cells, each of which is composed of a shell and a cover. One end of the shell is open, and the cover is provided with a negative terminal and multiple positive terminals, as shown in the figure below. Figure 2 shows the cover, the central cylinder is the negative electrode, and the three raised cuboids around it are the positive electrodes.

According to the description of the patent, the shell is in the shape of a regular hexagonal prism and is made of aluminum alloy. The pole core is a cylindrical winding pole core and is arranged in the accommodation space.

The height of the shell is between 60 and 150 mm, and the diameter of the inscribed circle of the shell is between 15 and 60 mm. Tesla's 4680 is 80 mm in height and 46 mm in inner diameter, which is also between these two ranges.

The patent also adds: "Optionally, the height of the housing can be 90 mm, and the diameter of the inscribed circle of the housing 1 can be 40 mm", which may be the preset size of BYD's hexagonal battery. If so, it looks about the same size as Tesla's 4680.

What are the advantages of making it into a hexagonal prism?

An intuitive understanding is that space utilization can be improved. When cylinders are placed close together, there will inevitably be gaps, while hexagonal prisms can be arranged more densely.

According to the patent description, this type of battery can increase the capacity of the pole core, and the shell can hold more electrolyte to extend the service life of the pole core. At the same time, when multiple batteries are connected into a battery module, the external space utilization rate is effectively improved to avoid battery short circuit or open circuit. The battery can meet the layout requirements of battery modules of various sizes, so that the battery module is suitable for various environments.

As for the specific performance, this patent does not provide a detailed description. I will continue to follow up.