Briefly analyze the key points of soft pack lithium battery module design

Design points of soft pack lithium battery module The battery module can be understood as the core product of the battery. It is a battery pack and battery pack composed of lithium batteries in series and parallel, and is equipped with single-cell monitoring and processing equipment. Its structure is necessary to support, fix and maintain the battery, which can be summarized into three categories: mechanical strength, electrical function, thermal function and fault handling capability. Can the cell position and maintenance be completely fixed without damaging the functional deformation, how to meet the requirements of the current-carrying function, how to meet the temperature of the control cell, whether to encounter a serious abnormality when shutting down, whether to prevent the transmission of heat out of control, etc., will Standards to judge the quality of battery modules. The solution for high-functional demand battery modules has been changed to liquid cooling or phase change data. The energy density of the soft pack battery is the most common method of three-lithium battery assembly, the simplest is the highest, but at this level of module planning, the safety of the entire product is the most important task, which can be said to be a part of a unit module structure. The important part of the module is the key soft pack battery of the soft pack lithium battery module planning. It is a big gap plan choice. The above is a relatively typical Chinese style. Its basic components include: module control, please (from the board of directors often say BMS) , Battery cell, conductive connection block, plastic structure, cold plate, cooling pipe, clamps at both ends, fasteners that combine these components. In addition to the functions of collecting single cells and supplying a certain pressure, the pressure plates at both ends of the module usually plan the fixed structure of the module on the top packaging. Structural planning requirements for structural planning. Sturdy structure: anti-feeling and anti-fatigue; process control: no over-welding or virtual welding to ensure that the battery is 100% free of damage; low cost: low cost of automation of the packaging processing line, including processing equipment and processing loss; easy to disassemble: easy to maintain , Maintenance, low cost, can be in a good echelon in battery use; make necessary heat transfer barriers to prevent heat out of control and rapid diffusion. This step can also be considered in the packaging plan. It is known that the mode power of a professional cylindrical battery is about 87%, and the mode power of the system is about 65%. The power consumption of the soft package core module is about 85%, and the power consumption of the system is about 60%. The module power of the square battery is about 89%, and the module power of the system is about 70%. The single-energy density of soft-packed batteries has higher room for improvement than cylinders and squares, but it has higher requirements for module planning and it is difficult to control its safety. These are the problems solved by structural planning. General module optimization method. Improving space utilization is also an important way to optimize modules. The power pack company can shorten the battery spacing by improving the module and thermal management system planning, thereby increasing the utilization of the space in the battery box. Another solution is to use new data. For example, the bus bar (bus parallel circuit, usually a plate made of copper) in the power lithium-ion battery system replaces copper, aluminum, and module fasteners instead of high-strength steel and aluminum metal plate data, which can also reduce power lithium-ion The weight of the battery. The physical structure of the hot plan soft pack battery determines that it is not easy to rupture, usually only the shell can withstand high enough pressure, there may be an explosion, and the internal pressure of the soft pack battery is very large, and it will be aluminum plastic from the beginning. The membrane is decompressed and leaks. There are also several battery structures that can be used with the soft-packaged battery, which has the best heat dissipation effect. The well-known representative of the soft pack battery, Nissan's Leaf, has a completely sealed module structure and does not consider heat dissipation, that is, there is no heat dissipation. This is related to the rapid decline of Leaf's frequent feedback in the market. Obviously, with people's pursuit of high-performance electric vehicles, the flexible packaging battery is forced to have an automatic heat conduction structure. At this time, the mainstream cooling method has been changed to liquid cooling and phase change data cooling. Phase change data cooling can be used in combination with liquid cooling, or it can be used alone under less severe conditions. There is also a more commonly used technology than domestic, pouring glue. Disclaimer: Some pictures and content of articles published on this site are from the Internet. If there is any infringement, please contact to delete.