The heat dissipation design is accurate to avoid excessive temperature differences in the system. This is due to the requirements of the lithium battery's own performance. The performance and aging of the battery are closely related to the operating temperature. The production process of liquid-cooled plates is more complicated than ordinary air-cooled radiators. Liquid-cooled heat dissipation requires higher process reliability. Therefore, only manufacturers with strong technical deposits can provide reliable technical support.

　　The heat dissipation design is accurate to avoid excessive temperature differences in the system. This is due to the requirements of the performance of the lithium battery. The performance and aging of the battery are closely related to the operating temperature. The production process of liquid-cooled plates is more complicated than ordinary air-cooled radiators. Liquid-cooled heat dissipation requires higher process reliability. Therefore, only manufacturers with strong technical deposits can provide reliable technical support. The general production technology of liquid-cooled plate has the following types.

　　Buried Pipe Process

　　The buried pipe process is the most used liquid-cooled radiator liquid-cooled plate manufacturing process. Generally speaking, the aluminum base plate is buried in the copper pipe, that is, the aluminum base plate is machined and milled with CNC, and then a punching machine is used to form the bent copper pipe. It is pressed onto the aluminum substrate, then brazed, and then processed into a water-cooled plate.

　　Buried tube type liquid cooling plate generally has three forms: one is shallow buried pipe liquid cooling plate; the other is deep buried pipe liquid cooling plate; the third is welded pipe technology; the fourth is double-sided clamping pipe technology liquid cooling plate. The three types of processes are not much different, and the difficulty of processing is also the same. Some liquid cooling principles originally designed for high-power switching devices can also be used for reference in power battery cooling systems.

　　Shallow buried pipe process: suitable for single-sided installation, the copper pipe is flattened and milled at the same time as the aluminum plate, which is fully conducive to the high thermal conductivity of the copper pipe to take away heat, and the lightweight aluminum plays a role in weight reduction and cost control.

　　Deep buried pipe process: The filler is imported from the United States with high thermal conductivity epoxy resin. When the temperature difference of the cooled device is not high, it can be installed on single and double sides. Because of the thickness of the copper pipe, there is no secondary processing and the filler protection can provide application Safety, especially suitable for cold plates with refrigerant as the medium.

　　Welded pipe process: suitable for copper plate + copper pipe method to reduce the thickness of the plate to reduce weight.

　　Double-sided pipe clamping process: the device is installed on both sides, the process is simple and the cost is low; aluminum plate + aluminum tube & copper tube & stainless steel tube.

　　profile + welding

　　Liquid-cooled radiators processed on the basis of profiles. Such radiators have many shapes, and there are many types, including plate type, channel type, and combined type. The general production principle is based on the profile. For processing and welding, the profile and joint pipeline are combined into an integral liquid-cooled radiator.

　　The cold plate runner is directly formed by the extrusion process, and then the cycle is opened through the machining method. Usually, friction welding, brazing and other welding processes are used for sealing. This process has high production efficiency and low cost; it is not suitable for excessive heat dissipation density The application is not suitable for application conditions where there are too many screw holes on the surface to limit the direction of the waterway or reduce the reliability. Mainly used in: power battery water-cooled heat dissipation heating device, water distribution box and standard power module integrated heat dissipation products.

　　machining + welding

　　The water-cooling board adopts the method of mechanical addition, and the internal flow channel size and path can be freely designed. It is suitable for thermal management products with high power density, irregular heat source layout, and limited space. It is mainly used in: wind power converters, photovoltaic inverters In the design of heat dissipation products in the fields of IGBTs, IGBTs, motor controllers, lasers, energy storage power supplies, supercomputer servers, etc., they are rarely used in power battery systems.

　　Micro-channel radiator is also a kind of radiator manufactured by combining machining and welding processes. It is more complicated to manufacture than other radiators. Micro-channel radiators are generally used on machines with higher heat dissipation power and more concentrated heat dissipation. Because the channel is wider and more uniform, the concentrated heat can be quickly taken away.

　　However, the manufacturing process of the liquid-cooled radiator of the micro-channel is also more complicated. Generally, the micro-channel is machined and then the friction welding process is used for welding, and the manufacturing cost is also high.

　　die casting + welding

　　The die-casting process is a very mature and widely used molding method. With the rapid development of new energy vehicles, it has become the first choice for mass production of motor controllers, power battery pack trays and heat dissipation boxes. However, it is necessary to control die casting impurities, For issues such as pores, conservative use of sealing ring methods or friction welding methods, it is necessary to improve the reliability of the process to avoid the problem of water leakage.

　　die-casting molding and then welding, the process is well controlled, and the process is stable, with the ability to deliver in batches. In addition to the friction welding process, some water-cooled plates will also use brazing or vacuum brazing.

　　This type of water-cooling plate can be considered together with the die-cast box of the battery pack. The lower water-cooling plate of the AudiQ7PHEV is such a usage. At the Beijing Auto Show two days ago, we have seen the prototype display.

　　Typical vehicle water cooling plate

　　In the power battery system, there are many ways to take the heat away from the surface of the battery cell. Only the scope of action is different. It can be divided into a battery-level water-cooling plate integrated inside the module and a module-level water-cooling designed outside the module. plate. Below are several pictures from the public account of "Power Battery Thermal Management Technology" to illustrate the application of water-cooled panels in actual cases.

　　Modular level water cooling plate

　　As a whole, the water-cooling plate acts on one or more battery modules at the same time. The water-cooling plate is a component of the entire battery pack, not a component of the battery module. We put it under the heading of the module-level water-cooling plate.

　　Square battery liquid cooling systems mostly use module-level water-cooled plates, and they are generally placed at the bottom of the battery box; soft-pack battery liquid-cooled is mostly in the form of integrated small water-cooling plates inside the module, and there are also modules integrated with aluminum plates and molds. A module-level liquid-cooled plate is set outside the group; cylindrical batteries and a serpentine tube led by Tesla are the main liquid-cooled radiators.