Lightweight all-composites enclosure for electric vehicle battery

Mitsubishi Chemical Group (MCG), Japan exhibited its newest innovation in the form of an electric vehicle battery all-composites enclosure as the centrepiece of its activities at The Battery Show held recently in North America.

Mitsubishi Chemical Group announced that the partnered collaboration features it with a diverse fibre-reinforced composites material portfolio for advanced energy storage systems, EDAG (Germany) contributing its key engineering services to the mobility sector, and Kreisel Electric, specialized in designing and manufacturing battery storage systems. The latest design overcomes many of the concerns surrounding traditional electric vehicle (EV) battery enclosures. Typically, these are produced from heavy metallic profiles which can have a negative impact on overall weight and vehicle performance.

By switching to composite materials, this battery concept can meet the requirements for battery housings for electric vehicles, while at the same time, being significantly lighter in weight.

John Conn, Engineering Project Manager at Mitsubishi Chemical Group, commented: “This is an exciting breakthrough that can make a real difference to the electric vehicle market, which is growing quickly as more people move to EVs. In addition to being extremely lightweight, the functional composite structure offers robust performance, high safety levels, and strong durability.”

Another key feature is that the composites enclosure is a simpler system with just two parts, compared to the initial EDAG design based on a metal housing comprised of five parts. This demonstrates the ability of composites to consolidate parts resulting in simplified downstream processes and cost savings. In addition, some components are recyclable and can include the use of recycled content, making for a product with high circular economy credentials.

Various MCG composite materials were incorporated within the battery enclosure, including a flame-retardant fibre-reinforced thermoplastic material for the Top Cover that can withstand high-intensity thermal runaway events. The enclosure also incorporates an additional layer of insulative material produced from alumina fibres to further protect the battery cover. The Bottom Tray was developed using two different materials, Prepreg Sandwich and CF FMC (Forged Moulding Compound), produced using an innovative single process step to meet thermal, geometric, and structural requirements. In addition, MCG fabricated its own tooling and produced the assembly in-house, demonstrating an agile, vertically integrated value chain that can be adjusted to meet OEM requirements to create bespoke solutions.

Designed by engineering service provider EDAG, the lightweight enclosure has been developed in collaboration with battery system manufacturer Kreisel Electric utilizing its patented immersion cooling technology.