Die casting battery pack case

Lightweight is a problem that cannot be avoided by electric vehicles. In addition to the weight reduction of the body structure, the battery pack itself needs to be lightweight. Among them, the weight reduction of the battery case is one of the directions of efforts.

Especially for the battery pack of pure electric vehicles, in pursuit of the high driving range under the premise of the current development level of lithium-ion batteries, it is necessary to do everything possible to reduce the weight of the battery box (the stimulation of subsidy policy is also a double-edged sword, on the one hand To a certain extent, it encourages manufacturers to develop high energy density and objectively promotes the development of a certain aspect of battery technology; on the other hand, blindly pursues the high energy density of battery packs, resulting in the one-sided pursuit of single indicators and narrow propaganda by individual manufacturers; In addition to the high energy density, the high-density battery pack does not have a good battery pack design.

The starting point of the subsidy policy is benign. The policy blind spot is used to a certain extent uncontrollable. After lessons have been learned, the policy can be corrected and improved. At the same time, high structural strength is required. Lightweight aluminum alloy is used instead of steel material. Generally, the weight can be reduced by 10-30%, which can reduce the overall weight of the battery pack to a certain extent.

The process of aluminum alloy box generally has die casting and extrusion, and the die casting box can be integrally formed (flatness and precision are affected to some extent, especially if the installation interface has sealing requirements, it may need post processing to deal with), do not need to fight Welding, which needs to be realized by a large-tonnage die-casting machine, is generally limited by size, and the size of the box is not too large, and is generally used for a battery tray (or a lower box). When the size is large, the tailoring process can be added to make up for it. This type of cabinet can meet the IP67. Below are examples of battery trays for several die cast aluminum alloys.

The GM Cadillac CT6PHEV battery case uses a stamping and high pressure casting process (below), and the tray Tray uses aluminum high pressure casting (HPDC).

Usually, the application of die-casting aluminum alloy in the tray can be low-pressure casting or high-pressure casting. According to different requirements, it is also possible to integrate the cooling function inside, omitting the separate cooling plate, which may be one of the future trends.