Transition to electric vehicles spurs rapid manufacturing innovation

Practices that worked for building highly efficient internal combustion engine vehicles will not be viable for competitively producing EVs, writes Bas Bonnier

The last few months have seen electric vehicles (EVs) buoyed up, especially in Europe where July 2020 was a record-breaking month for EV registrations. According to JATO, a provider of automotive data, volumes that month rose 131% year-on-year to 230,700 units—the first time that these vehicles were bought by more than 200,000 consumers in a single month.

The transition to EVs is driving rapid change in the way carmakers and the automotive industry supply chain manufacture their products. What has worked for building highly efficient internal combustion engine (ICE) vehicles is not going to be viable for producing EVs competitively over the next decade. The challenge is to create a mass-market manufacturing environment on a par with conventional cars and make EVs a viable and profitable scale business—none of which is the case right now.

The future of factories and components

To date, many established carmakers have used the same platform for both their ICE and EV models to protect investments and hedge their bets until demand shifts more fundamentally toward EVs. However, the industry has recently been moving more decidedly toward ‘skateboard’ platforms. Propelled by EV-only manufacturers such as Tesla – for which such a ‘from scratch’ approach is easier to realise – these platforms are designed exclusively for EVs.

The difference here is that a low, flat battery becomes the structural underbelly of the car, which can be adapted in size depending on different car models. Adding to this are compact motors placed at the ends of the skateboard corners, which are less bulky than traditional ICE engine and transmission blocks. Finally, drive-by-wire accelerators, brakes, drive control and steering replace typically hard-mounted parts with digital technology. The skateboard approach enables OEMs to set up a modular manufacturing process, which gives them greater flexibility and will ultimately save costs.

One advantage is that any number of car bodies can be married to the skateboard, extending the platform approach already used in ICE mass production. Unlike a traditional chassis, this type of platform doesn’t set specifics in stone, increasing the ease with which car makers can adjust to customer demands. It also reduces the complexity of the production process with obvious implications for costs.

Innovation in the supply chain

Just as OEMs are having to change their products and processes, so too are their suppliers. Demand for some parts that played key roles in modern ICE production may decline or shift toward new technologies. Below are some technologies that are likely to see substantial change as the industry moves towards EVs.

Turbochargers

Turbochargers have long been a mainstay for automakers, enabling greater fuel efficiency and helping to lower emissions and comply with ever-tightening regulation in diesel and gasoline vehicles. Globally, rising demand for cars will drive the continued need for turbochargers over the next decade when the market is predicted to peak. In the ICE space, this trend, and the need to lower fuel consumption and emissions will continue to drive advances in turbo performance. For example, recent engine improvements for gasoline cars to raise fuel efficiency are creating a greater need for variable-geometry turbos to help meet emissions limits. In turn, these require new material compositions to work at the high exhaust temperatures needed to comply with regulation.

Beyond 2030, we will see a de-contenting of car technology as powertrains become more diverse and the share of ICE engines drops off. Increased hybridisation and the move to EVs will change demand patterns for turbos. Hybrid vehicles will still require turbochargers, and we will see electrically assisted systems coming to the fore. As we move toward fully electric vehicles, demand for new turbo technologies such as range extenders will grow: these are small gas-turbine generators that act as a compact backup power source when the main battery runs flat. Not only do these solutions increase driving distance and independence from recharging infrastructure, but they also allow for smaller battery packs to be built in without compromising range.

Mitsubishi twin-scroll turbocharger
The turbo supply chain will need to adapt to coming changes in demand

For fuel-cell vehicles, which use hydrogen as a propellant, air-compressors will be needed to pump air into the fuel cell to react with hydrogen, again drawing on turbocharging technology—where air-compressors are a key component. Benefitting from this technology transfer, these vehicles will not only be CO2-free, they are also expected to offer driving range and refuelling times comparable to ICEs. The turbo supply chain will need to work ahead of the curve to ensure it can adapt to the changes in demand expected over the next decade and beyond.

Internal gearing

In ICEs, complex gear ratios are needed to keep the engine within a narrow range of engine speeds, or revs, to optimise torque and power as the vehicle accelerates. In contrast, EV motors are high-revving and efficient across a broad range of revs, so only a single-speed transmission is required. However, to address range anxiety as a barrier to EV uptake, OEMs and drivetrain suppliers are working on multi-speed transmission systems using planetary gearing, a technology already at work in automatic gearboxes.

Planetary gears enable lightweight, compact gearbox designs with high reduction ratios, leading to increased mileage from more efficient battery use, especially when driving out of town or on motorways. This leads to another problem: noise and vibration. With ICEs, gearing noise is usually covered up by engine noise. More gears in EVs carry the risk of greater noise levels—with no engine to block them out.

Noise, vibration, and harshness (NVH) arise due to distortions to the surface quality of the gear, which can also affect the performance of the transmission overall. To increase the quality of gearing and reduce these unwanted side effects, new production methods are needed. To achieve high-level NVH performance, gear grinding and honing have become the standard for making external gears. But for internal gears, several hard finishing processes, such as hard skiving, honing and grinding are now being investigated to gauge their effect on transmission performance. Initial results show the impact of new approaches such as Super Skiving, which combines three conventional gear cutters into one tool, on advancing productions processes. Tests also suggest that internal generating gear grinding can improve transmission errors, vibration levels and the sensitivity of each gear parameter.

Manufacturing
EVs are changing automotive factory layouts and processes, as well as the key components used in production

Air-conditioning and thermal systems

Like gearing, new powertrain technology also raises new challenges in areas such as the vehicle electrics, including air-conditioning and thermal systems. For air-conditioning, conventional vehicles use belts connected to the engine to rotate the air-conditioning compressor. In EVs, electric-driven compressors are used, meaning that controllers and inverter boards are employed to allow the air-conditioner to function without a conventional engine. These electric compressors are a core component of EV air-conditioning, but they also put a strain on fuel efficiency and must operate as energy-efficiently as possible to ensure minimum impact on range.

Similarly, electric water heaters step in as a heat source for EVs and hybrids, taking the place of engine waste heat in ICEs. In PHEVs, the use of electric water heaters means that drivers do not have to run the ICE engine as a heat source, contributing to better fuel economy.

In an ICE, engine waste heat is also used for heating the cabin. In EVs, an electrical heater typically takes on this function, but their use drains the battery and reduces the driving range. Heat pumps provide a less energy hungry solution: they heat the cabin by absorbing heat from the air outside the vehicle, drawing significantly less battery power. Tests conducted by Mitsubishi Heavy Industries have shown that an EV’s driving range can be improved by 20-30% using heat pump technology.

Collaboration

Huge challenges require a collective effort, and the automotive industry has recognised this. For a competitive sector, its uptake of collaboration has been surprisingly high, especially in the context of developing EV designs. Innovation is becoming increasingly open and collaborative as technology becomes more complex, and companies are casting aside traditional concerns over Intellectual Property and accepting that they can no longer be lone fighters. They need to build ecosystems to survive and thrive.

Pushing EV take-up beyond the tipping point does not solely depend on the OEM community and its suppliers. It needs strong commitment from the surrounding ecosystem—governments, regulators and the car-buying public—too. However, the car industry’s contribution to making EVs affordable, and on a par with ICEs in range and performance, will be crucial to accelerated mass uptake. Only then can manufacturers expect the scale economies and experience curve effects needed to make EVs break through.


About the author: Bas Bonnier is General Manager Turbocharger Operations at Mitsubishi Turbocharger and Engine Europe B.V.

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