Top Trends in Modular Electric Vehicle Design

This piece is part of the FEV Blog series, providing accessible information about the key trends and factors affecting the push towards sustainable mobility and energy solutions. For more detailed technical information, please contact marketing@fev.com to talk with the proper FEV expert.

As more automakers plan to enter the electric vehicle market, the design criteria—and the many factors that affect tooling, plant design and manufacturing complexity—are a key focus of discussion. This blog provides a high-level overview of the kinds of choices that EV developers face early in the design process. These decisions can drive costs up or down, and either accelerate or delay time to market.

Native EV or modified ICE design?

Among electric vehicles on the road today, some are native, or purpose-built EV designs, while others are modified versions of internal combustion engine (ICE) designs. For new vehicles entering the market, native designs offer more potential for success—with EV-optimized chassis and the advantages of modular components.

The importance of modularity

For flexibility, versatility, and economies of scale, modularity is essential. With a modular EV design, different vehicle models can share the same platform or components. This can accelerate development and provide manufacturing efficiencies, resulting in significant cost savings. With modular components parts sourcing is more efficient, and inventory management, processing, and storage are simplified. One plant can produce multiple vehicle variants far more easily and efficiently, with less complexity of retooling and physical layout changes.

Engineers face many design choices when planning a modular design—key among them are the choice of base platform, and the placement and design of the batteries.

As a world leader in electric vehicle design and development, at FEV, our engineering and experience puts us at the forefront of modular design. We are design and technology partners for EV startups, seeking to leverage our rich product development expertise in order to reduce their risks and help them enter the market with truly winning products.

The skateboard platform: a fast track to proven performance  

The simplicity of EV—as compared with ICE—powertrains allows for a whole new approach to vehicle platform design. The low, flat “skateboard” platform, with an integrated battery platform and chassis, can be the basis for a wide variety of vehicle designs. Its flexibility allows unique vehicle designs, with enhanced performance. Choosing a skateboard platform as a starting point can save manufacturers on R&D, design and development time, and a variety of related

Skateboard platform advantages:

• Reduced design and development costs
• A flexible architecture that can be used for a variety of vehicle types
• Economies of scale
• Proven performance from an integrated chassis

The skateboard platform’s limitations are that it is a fixed platform: its size, geometry, maximum range, and other core performance attributes cannot be easily changed. The same factors that make it appealing, also set its boundaries. Done right, a skateboard-based design can be brought to market more quickly. But that speed comes with caveats. An EV developer that bases their designs on a pre-existing skateboard chassis will be responsible for any engineering or integration issues that arise, and for validating the performance of complete vehicles.

Modular kits and subassemblies: flexibility comes with integration complications

Using modular kits and subassemblies can save design and development time. Typical modules include battery-pack subassemblies that are mated to front and rear suspensions. Using a kit-type approach can provide design flexibility without the constraints of a skateboard’s fixed dimensions. However, the EV developer will be responsible for a greater level of vehicle design, engineering and integration, with more challenges in vehicle validation.

Underfloor battery design pros and cons

The majority of EVs on today’s market package their batteries under the floor (as in the typical skateboard platform, above). Some put batteries in unused interior space behind the front seat and in the rear compartment.

Underfloor batteries lower the vehicle’s center of gravity, which has handling and performance advantages, in addition to increased trunk space. However, the additional underbody structure that is required to support the batteries may increase total vehicle weight, and attachment points may require additional validation. The depth of the batteries can also reduce the vehicle’s ground clearance and limit its ability with respect to deep water fording. 

Stacked battery design pros and cons

A stacked battery design is an alternative to underfloor batteries. Stacked batteries are, in general, placed in a grid or row, or their placement may be adapted to the vehicle’s floor. Design options for battery stacks depend on the configuration of the battery cells themselves; the most common cells are cylindrical.

The negative to stacked batteries is packaging. They can reduce available cabin volume and/or reduce ground clearance, while at the same time increasing thermal and cooling concerns due to compromised placement. Many vehicle OEMs use this method to offer extended-range options, and the vehicle designs must be able to accommodate all battery packs in the allotted space.

Other trends

As the electric vehicle market matures, there are additional trends and considerations that EV developers need to be aware of:

• Lightweighting 
  Vehicle lightweighting is a trend with no end in sight. One should expect to see greater use of mixed material technologies, and perhaps technology alliances that lead to new compact battery cells, modules and packs, as we have seen with mobile phones.
• ADAS and AV technology
  Driver assistance and autonomous vehicle technologies will continue to increase in sophistication and reliability. 
• Automated manufacturing 
  Manufacturing plants already require less labor, but more highly skilled workers, and this trend will continue. This will mean smaller manufacturing plants, with annual volumes likely under 100k.
• Kit-based designs 
  While kits will lead the way at first, eventually, overall cost of ownership will lead to fewer solutions dominating.

For specialized EV development experience, talk to FEV

For EV startups, innovation will drive success. The market will respond to forward-looking vehicle designs that meet the needs—and high expectations—of the driving public; whether for personal or commercial use.

The path from design through development to ultimate validation can be long and challenging, with significant risks and costs that constantly threaten to balloon out of control. Partnering with an experienced EV developer—like FEV—can dramatically reduce risk, shorten the development cycle, and maximize the return on investment. FEV has partnered with many global OEMs on their EV programs, and even developed our own SVEN (Shared Vehicle Electric Native) vehicle as proof of our modular concepts and capabilities.

FEV offers advanced in-house design, testing, and project management; with EV-specific expertise in battery development and integration, and power-dense driveline design. Working with our partners we develop new concepts, design and construct parts and modules, and develop chassis designs to meet specific driving dynamics. We can contribute from component or drivetrain development to complete turn-key vehicle development solutions.

The FEV SVEN: from design through manufacture

We designed and developed the FEV SVEN—a Shared Vehicle Electric Native car—from the ground up. This compact electric car demonstrates our capabilities in design, development, engineering, and management. Everything in the vehicle, from its architecture and chassis to its electric drivetrain and its interior design themes, were developed and validated in-house by FEV. As an outstanding example of a compact EV, SVEN will be part of the redesigned transport exhibition at the renowned Deutsches Museum in Munich, Germany, beginning October 2021, which focuses on the future of mobility.