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DESIGN ENGINEERING

COMPOSITE BENEFITS

ENCLOSURES

JARI SOPANEN OF EXEL COMPOSITES EXPLAINS HOW
COMPOSITE EV BATTERY ENCLOSURES COULD SUPPORT
THE OVERALL LIGHT WEIGHTING MISSION, AND
PROVIDE ADDITIONAL STRUCTURAL BENEFITS
COMPARED WITH THE TRADITIONAL METAL OFFERINGS

attery enclosures for EVs, also called frames, case of EV battery enclosures, as
boxes or housings, have a primary purpose of composites offer weight reduction,
holding and protecting the battery cells. They improved insulation, reduced noise,
Bcome in different shapes and sizes, and much vibration, and harshness. Let’s look
like other vehicle parts, are an arena for several materials closer at each characteristic:
fighting for prominence. Arguably the main driver of
The United States Environmental Protection Agency choosing composites, up to 40 per
(EPA) says the for every 100 pounds of weight taken out cent in weight savings is achieved if
of a vehicle, the fuel economy is increased by one to two the enclosure is made from 100 per
per cent. This holds opportunity for the electric vehicle cent composite material rather than
(EV) sector, which is fighting to boost energy efficiency aluminum. A lighter battery box made from composites While not a safety critical factor, a quieter vehicle is a
and quash ‘range anxiety’. Aluminum and steel are has a positive knock-on effect on the entire vehicle design. more commercially viable vehicle. Noise vibration and
traditional material choices for battery enclosures. Yet, With a lighter vehicle weight attributed to the battery harshness (NVH) is the result of vibration or noise, which
composites could provide an improved alternative, which enclosures, smaller batteries and a reduced engine sizes is transmitted and radiated acoustically in the cabin. NVH
will significantly improve the performance of the EVs. are required to haul a lighter vehicle. This positive spiral is less with composites than with metals, as they have
Mass EV adoption is currently held back by range results in reduced vehicle cost and range anxiety, which inherent damping properties. This is true for the battery
anxiety – concerns that vehicles won’t be able to travel far will play a big role in the mass adoption of EVs. enclosures as well as other vehicle parts and could mean
enough on a single charge. To alleviate range anxiety, the difference between a luxury driving experience and a
there is an unquestionable need for safe, lightweight and Insulation properties less comfortable one.
cost effective EVs. For these EVs to make it in the market, Aside from being a lighter material in their own right, Looking at the wider vehicle, composite battery casing
the components that form them must also possess these composites take away the need for a separate insulation can be designed as part of the vehicle body structure, not
qualities. If a part can be made using a lighter material system, which reduces weight even further, as well as only protecting the battery, but also the passengers of the
without compromising safety and function, then it’s a no- helps streamline the supply and value chain. With metal vehicle. The strength and stiffness properties of
brainer for designers and material selectors in original battery enclosures, an added insulation system around the composites outweigh those of aluminum or steel,
equipment manufacturer (OEM) and System Supplier material is required to keep the batteries in operational providing better crash safety. This integration will require
businesses. temperatures. Due to the insulating properties of close collaboration between the battery enclosure
In some instances, switching from metal to composite composites, these materials already do a good job of suppliers and chassis designers, but offers a real
doesn’t just match previous functionality, it surpasses it by preventing heat transfer, without the need to add more possibility to boost vehicle safety.
bringing in additional benefits. This is demonstrated in the weight-increasing parts in the system. High volume production is essential in reducing overall
costs. It is possible to use continuous manufacturing
methods to produce EV batter box components, such as
pultrusion. Pultrusion as a process enables composite
manufacturers to pack in more fibers in the same cross
section, compared with other composite manufacturing
methods, allowing stronger, but lighter parts to be made.
Remember, the fibers are the part that carries the load
in the material. Working closely with the composite
manufacturer allows you to precisely engineer the fiber
content and alignments to achieve the best possible
strength-weight properties.
If OEMs are going to reap the energy economy returns
of light weighting that the EPA predicted, composites will
no doubt play their role. This could be a much bigger role
than simply reducing the mass of the vehicle, but also
improving crash safety, driving dynamics and experience
as well as overall strength of the vehicle. Range anxiety
remains one of the key hurdles that the EV sector must
overcome, and thinking outside of the conventional
material choices for battery enclosures are essential steps
to reducing vehicle weight, and reaping fuel economy
returns.
MORE INFORMATION: www.exelcomposites.com

14 INDUSTRIAL TECHNOLOGY • June 2021