The battery shells material should have the characteristics of electrical insulation, high heat dissipation and chemical stability.
The case is generally composed of upper and lower cases and a sealing system. The mass of the battery pack accounts for 18% to 30% of the mass of the vehicle system, while the case mass accounts for about 10% to 20% of the total mass of the battery pack. At present, metals are widely used as battery pack case materials, and composite materials are gradually gaining attention due to their excellent specific rigidity.
Metal materials for battery pack cases
Among the metal materials used for battery pack cases, steel plate materials have a simple manufacturing process and low cost, and have good thermal conductivity, impact resistance and thermal management capabilities. They are commonly used materials for cases, but their main disadvantage is that they are heavy. With the deepening of the concept of lightweight design for automobiles, aluminum alloys have gradually become the main material for achieving lightweight automobiles due to their advantages such as low density, high rigidity and good die-casting performance. At present, products such as cast aluminum battery cases, aluminum plate battery cases and aluminum profile battery cases have been produced. Among them, the load-bearing structure of the aluminum battery pack case is mainly divided into bottom plate type and frame type. Volkswagen has found that the box with a frame-bearing structure can meet the strength requirements of different structures and is easier to achieve lightweight. In addition, the combination of metal and plastic is also the main way to achieve lightweight battery pack boxes.
Battery pack box structure made of different materials
ThyssenKrupp Steel selectrify® battery shell
ThyssenKrupp Steel Europe’s R&D team has been working hard to find solutions for future problems in electric transportation. In the future, ThyssenKrupp Steel Europe will integrate its high-level electric transportation materials and application expertise under the name of the selectrify® program, including lightweight automotive structural solutions, highly stable and safe battery shells, and efficient drive motors and charging piles made of electrical steel. Patrick Tlauka, project manager of ThyssenKrupp Steel’s selectrify® program, believes that the use of ultra-high-strength steel in electric vehicles has great potential. As part of the selectrify® program, ThyssenKrupp Steel has developed a battery shell made of high-strength steel. In addition to lightweight and collision safety, the battery housing has significant advantages in fire protection, electromagnetic compatibility and cost-effectiveness, and can provide excellent safety protection for the most sensitive and expensive component of electric vehicles – the battery.
Magna Battery Housing
The lightweighting of the battery housing is an important topic. Magna’s aluminum housing helps to control the additional weight of the pickup battery very well. Its aluminum extrusions and stampings are connected by laser hybrid welding and cold metal transition welding (CMT) to ensure overall strength.
Magna is leading the automotive structural design of the entire industry through its technical expertise in body and chassis, providing comprehensive services and engineering solutions to customers around the world. We develop battery housings in steel, aluminum and multiple material configurations, including battery housings made of lightweight composite materials, to meet the personalized needs of each customer.
Future Development Trends in Lightweight Shell Materials
The application of high-strength steel, ultra-high-strength steel, aluminum alloys, and composite materials is a necessary link in achieving lightweight new energy vehicles.
2020-2025: The lower shell is mainly made of ultra-high-strength steel and extruded aluminum profiles, some of which are made of carbon fiber composite materials, and the upper shell generally uses composite materials.
2025-2030: The lower shell is mainly made of extruded aluminum alloy and ultra-high-strength steel, some of which are made of carbon fiber composite materials, and foam aluminum alloy is used exploratoryly, and the upper shell is mainly made of composite materials.
2030-2035: The lower shell is mainly made of extruded aluminum profiles, some of which are made of carbon fiber composite materials and foam aluminum alloy, and the upper shell is mainly made of composite materials.
Although lightweight materials have great advantages, high-strength steel has the advantages of high safety, low cost, low processing difficulty, mature production lines, and low carbon emissions at the production end, and it still has certain competitiveness. Therefore, steel companies such as Posco, ArcelorMittal, and Baosteel are still developing high-strength steel lightweight battery packs, and combining lightweight, cost and safety to form corresponding solutions.
Therefore, with the increase in production and sales of new energy vehicles in the future, more scale-effective battery pack shell solutions will also appear. Whether it is aluminum alloy, steel plate or composite material, it will be reconsidered by enterprises, and lightweight, cost and safety are the core issues. Investment institutions, vehicle companies, etc. will comprehensively consider various factors (market, product positioning), rationally analyze and decide what materials to use. In the future, based on differentiated competition, the final result may still be that different types of materials occupy their respective stable shares in the field of battery pack shell manufacturing. If you need to make metal shell products in large quantities, you can choose to cooperate with Mulan Group, which provides battery shell custom. Distribution cabinets, cabinet customization services, support IP7-6 waterproof technology, with complete certificates and qualifications. Customized metal shell products are exported to more than 30 countries and regions.
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