Toyota’s chief scientist doubles down on hybrid advantages


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Toyota chief scientist Gill Pratt explains how fitting more cars with smaller batteries could reduce emissions faster.

Toyota has doubled down on its belief that battery-electric vehicles cannot be the only approach to reducing emissions, citing numerous advantages of hybrid and hydrogen drivetrains as reasons for its ‘multi-tech’ approach to vehicle development.

Speaking at Toyota’s annual Kenshiki forum, the company’s chief scientist, Gill Pratt – who recently said that he believes “the correct solution isn’t a single technology” – outlined how limited battery materials could be better deployed in the short to medium term by vehicle manufacturers as a means of reducing their carbon output.

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Ultimately, he said, replacing 90 per cent of pure-ICE cars with hybrids equipped with a 1.1kWh battery would have a bigger impact on overall emissions than replacing 6 per cent of pure-ICE cars with battery-EVs, because the overall emission figure for the 100 cars would be vastly reduced – in his scenario, 205g/km compared with 244g/km.

Essentially, Pratt’s argument is that spreading scarce battery materials across a wider vehicle parc – while not increasing the number of pure-EVs on sale – would reduce overall emissions more effectively.

His comments come as Toyota reveals a concept for its second bespoke EV, the bZ Compact Crossover, and two new big-selling plug-in hybrids: the Mk5 Toyota Prius and Mk2 Toyota C-HR.

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The lifespan of hybrid (HEV) and PHEV cars in the EU and the UK is limited by the imminent imposition of combustion car sales bans in 2035, but Pratt’s remarks suggest such cars could play a vital role in making personal mobility more sustainable, while maintaining comparable cost and convenience to today’s combustion cars.

“By utilising their batteries better, HEVs are also more affordable and easier to recycle,” he said. They also don’t need to be plugged in, which strengthens their use case in environments where EV infrastructure is under-developed.

“We want to distribute the limited supply of battery materials, where they will reduce carbon emissions as much as possible, as soon as possible.”

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“During the coming 10-15 years of battery material shortages, we believe that precious battery cells should not be squandered in only long-range BEVs, especially ones that have driven a short distance between recharges.

“Rather, we believe the battery cell should be put where they will do the most good.”

Pratt clarified that he and other Toyota bosses do not believe that hybrid and plug-in hybrid cars should forever be used in place of BEVs, saying that in “15 years or so” global lithium mining operations will be sufficiently developed to allow for larger-scale EV production – and battery recycling schemes will provide a significant material resource.

He also said that, in some parts of the world, it already makes sense to drive a pure-EV – like in Norway, for example, where electricity generated via renewable resources is readily available for charging. But, crucially, every market varies according to its customers’ demands and preparedness for battery-EVs, so Toyota will continue with a “multi-tech approach”.

“We can’t expect that a single powertrain is going to offer the optimal solution everywhere,” Pratt said. “Our goal is to reduce carbon emissions as much as possible, as soon as possible, and that’s why we say: carbon is the enemy, not a particular powertrain.”

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He also extolled the benefits of hydrogen powertrains – both of the fuel cell and combustion variety – as viable alternatives to batteries, particularly in the heavy goods vehicle sector – “where hydrogen’s lower mass and faster refuelling is essential”.

He theorised that an average battery-electric HGV would use around 10 times more power when charging, compared with a conventional passenger car, and take around an hour to fill up, compared with six minutes for a diesel HGV.

To which end, he estimated, every HGV diesel pump would need to be replaced by 10 chargers, each of which with 10 times the output of a standard EV charger, to facilitate the switch to battery-electric lorries and minimise downtime. “And remember that a truck stop may have several diesel pumps,” he said.

The amount of time and money that would need to be invested in preparing the grid to supply that level of power to a given location constantly would be “tremendous”, he said, whereas “hydrogen can refuel a truck as quickly as diesel with the same number of pumps”.

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