Simple Technology: EV Chassis Design

Electric vehicles are slowly approaching fossil-fuel vehicles in convenience and range, but there’s still a long way to go. The designers try to make the most of its components like battery and electric motors to maximize its performance in all aspects. Another important area that EV manufacturers have started to address is chassis design. The chassis of an electric vehicle, for obvious reasons, must be strong to protect its occupants in the event of a collision and rigid enough to withstand torsional vibrations, i.e. the twisting force exerted on the chassis in due to load and road conditions.

In addition, the chassis of an electric vehicle must be able to safely transport a heavy battery throughout its life. On the other hand, it must be light to save on the overall weight, which affects performance and efficiency. This last aspect is of great importance since the limited electric juice stored in the on-board battery should be used in the best possible way. The heavier the chassis, the lower the capacity battery it can carry for a given electric motor. This will surely reduce range, passenger/luggage carrying capacity and electric vehicles will apparently be of no use. Also, the choice of materials used should be such that it should do all the work described above without being extremely expensive, just like the lithium-ion batteries on board.

So what differentiates the chassis design of EVs from the current crop of fossil-fueled examples?
The conventional chassis design as we know it now consists of a ladder design and/or a more modern unibody design. Despite their fundamental differences, what brings them together is the fact that they are designed to house a myriad of components such as the heat engine, the gearbox, the drive shaft, the axle, the fuel tank fuel, brake, exhaust and clutch lines, etc. Furthermore, they were designed not only to withstand the punishment and vibration inflicted on them by the road, but also by the naturally unbalanced Internal Combustion Engine (ICE) bolted to them. Not to mention fast rotating transmission parts like gearbox, transfer shafts, differential, couplings in addition. A poorly designed chassis would transfer all vibrations to the cabin, making any journey uncomfortable. So, these chassis are strong and stiff enough to take all that abuse and have special anti-vibration resilient mounts welded onto them for various components, which also adds to their weight and cost.

Electric vehicles don’t need such a design simply because there are no vibration-producing components here. The batteries and control electronics are stationary and the only rotating component is the electric motor with a single rotating part called the rotor. It is therefore one of the smoothest motors in the world. Thus, there is no need for expensive heavy-duty fixings on the chassis to accommodate this. The chassis must therefore be strong and rigid, but of a much simpler design.

So, manufacturers came up with different models, the most popular of them being the one with a modular skateboard design. As the name suggests, this design resembles a skateboard, where two side beams run parallel to form a large, flat center section between which the battery normally sits. Then these beams extend front and rear to carry the electric motor with their control electronics for one or either axle or wheel. In addition, these extensions will carry suspension and steering brackets (front part) as well as fixings to transport the wiring to and from the batteries and the electric motor. Front and rear crumple zones are also located on these extensions.

One of the main advantages is that it can carry large batteries much lower in the center of the chassis, which lowers the center of gravity. This aids vehicle handling and stability and even distributes traction to all wheels. Additionally, this design conceals the battery within the rigid chassis side beams for improved crash protection. This chassis essentially carries almost the entire propulsion system on itself, which frees up space inside the cabin for passengers and luggage.

For engineers, this design makes maintenance easier and therefore cheaper. Since it is a modular design, it can be used in multiple models in the range, making the full range cheaper to manufacture. Materials for the main frame can range from carbon fiber to aluminum/zinc/magnesium alloys depending on cost and usage. Interestingly, everywhere else technology is moving towards lighter but expensive products. Here however, many start-ups and even traditional manufacturers have reverted to steel due to its availability and cost.

Speaking of which, such chassis design has also led start-ups to enter the EV space as its technology and materials are easier to source and manufacture, without requiring large manufacturing facilities and facilities. that only traditional manufacturers have. What emerges from the flood of start-ups like Okinawa, Ola Electric, Ather Energy, etc. in this space. Traditional car manufacturers like Tata Motors, Mahindra, Hyundai, MG Motors, Bajaj Auto, Hero Motors, etc. have also joined the bandwagon either on their own or through their affiliates, which is a good thing for us consumers.

Source link

About Leonard J. Kelley

Check Also

Do you have a skateboard? Take a survey to help guide the redesign of the Centennial Beach Skating Facility

Above / Do you recognize this skater from 2015? Do you think the skate facility …