Cars are getting bigger and heavier globally, and this is particularly true for electric vehicles (EVs).
China builds and buys more EVs than any other nation and the upsizing trend has taken root there too.
Some of the country’s fastest sales growth in recent years has been in medium-large and large SUVs. In the first four months of 2026, an average EV sold in China weighed almost two tonnes – up 27.5 per cent on 2020. Some large SUVs weigh over three tonnes. These passenger vehicles are now as big and heavy as a light truck.
Heavier vehicles need more materials, meaning more greenhouse gas emissions from their supply chains. That extra carbon offsets some of the emissions reductions from driving an EV over a conventional car.
Why the weight gain?
Liang Chenming is deputy secretary general of the China Society of Automotive Engineers. He notes bigger batteries, hybrid vehicles (featuring both electric and fuel power trains) and changing consumer expectations. People seems to want more range, more functions, more safety and more comfort. All of this means the constant addition of more features and ultimately “autobesity”.
Battery energy density is increasing, but range demands are going up even faster, so the car-makers add bigger batteries. The battery capacity of EVs has risen from an early 40 kilowatt-hours (kWh) to 80 kWh or even 100 kWh, today, show government figures. That means more range, but also more weight. A 100 kWh battery can weigh more than 600 kg, about a third of the car’s total weight.
Consumer desires for smarter and more comfortable vehicles aren’t helping. Lidar and millimetre-wave radar, high-powered processing platforms, multiple cameras and high-accuracy positioning systems – all this hardware makes mid- and top-range vehicles heavier.
Luxury features are gradually being added to mid-range cars – air suspension, electric soft-close doors, double-glazed windows, in-car refrigerators, large entertainment screens.
The computation required by self-driving features, meanwhile, also means more cooling and power are needed.
Automotive engineers say this leads to a “mass spiral”: bigger batteries need bigger frames, stronger chassis, more powerful brakes and better tyres and suspension – all of which need more materials and so add more weight.
Heavier cars mean more emissions
Ding Shanshan is the green supply chain director at the Institute of Public and Environmental Affairs (IPE), a Beijing-based non-profit. He told Dialogue Earth that upstream emissions, arising from making steel, aluminium, batteries and other inputs, often account for 70 per cent or more of a car’s lifetime emissions.
Heavier cars need more materials, and these are often carbon-intensive, greatly increasing manufacturing emissions, the IPE’s research has found. EVs have to be driven for a certain distance before they have lower lifetime emissions than a conventional car. For some small EVs, that happens after about 2,500 km. For SUVs in medium to large sizes it’s 54,000-140,000 km.
Batteries are a major part of manufacturing emissions. These emissions depend on the size of the battery, the manufacturing techniques used, and the source of the electricity used in manufacturing, as noted in a 2021 report by the International Council on Clean Transportation (ICCT), a non-profit headquartered in Washington DC.
On the European grid, making a ternary polymer lithium battery incurred emissions equivalent to 78 kg of carbon per kWh, while in China it was 105 kg. That’s according to a 2023 study by the European Federation for Transportation and Environment, a non-profit based in Brussels.
Steel is one of the most carbon-intensive materials in a car and accounts for 60-70 per cent of all materials used in a conventional vehicle. To keep weight down, many EV manufacturers use aluminium alloys, high-strength steel, or even carbon fibre, but aluminium smelting itself is energy intensive. The steel industry accounts for about 7-8 per cent of global emissions, the aluminium industry for 2 per cent. If the new materials are also carbon-intensive, the benefits of the weight saved will take longer to offset those extra emissions.
Bigger cars also use more energy when being driven, further driving up lifetime energy consumption and carbon emissions.
Autobesity syndrome
Heavier cars also mean more pollution and more safety risks.
Friction between tyres and the road increases with car weight, meaning more particulates in the air – a hidden form of car pollution. While the shift to EVs is reducing exhaust emissions, the heavier weight of those vehicles is bringing increased particulate emissions from tyres, brakes and road surfaces, found a 2020 report from the Organisation for Economic Co-operation and Development.
More wear on tyres means they need to be replaced sooner, increasing the cost of owning and maintaining an EV. Bigger cars can also mean more dangerous roads. A larger vehicle has more inertia and longer braking distances, making collisions more likely. A 2022 study by the US Insurance Institute for Highway Safety found that bigger, heavier cars were more likely to injure pedestrians. Overly heavy vehicles also do more damage to roads and bridges. Li Bin, founder of EV maker Nio, has said that an extra 20 per cent of weight on a car will cause damage to road surfaces to double.
Losing weight, cutting emissions
China is toughening up on carbon-footprint management, and with the EU’s new Batteries Regulation and Carbon Border Adjustment Mechanism coming into force, whole-lifetime carbon footprints will become a key part of competitiveness for Chinese car exporters. To maintain competitiveness and market access, manufacturers will need to make cars lighter, manage supply chain emissions and switch to low-carbon materials.
Manufacturers have been reducing weight at various stages of the process, using alternative materials, changing designs and manufacturing techniques, and managing supply chains better.
Technical solutions include expanding the use of high-strength steel, low-carbon steel and recycled aluminium; “gigacasting”, meaning casting the entire car body or big parts of it in one, rather than in panels to be fixed together; structural improvements; and multi-material integrated design. This will reduce the number of components and overall weight of the cars, and energy consumption during manufacturing.
Recycled aluminium uses only 5 per cent of the energy of raw aluminium to produce, says the US Aluminium Association, with a 90 per cent or more reduction in greenhouse gas emissions. The International Energy Agency has said that hydrogen-based direct reduction and electric arc furnaces are crucial for deep decarbonisation of the steel industry and will be able to dramatically reduce emissions from the sector. This will then reduce downstream emissions in car manufacturing.
At the Chinese policy level, more emphasis is being placed on energy efficiency in EVs. A national standard for EV energy consumption limits came into effect at the start of this year, for the first time linking vehicle weight with electricity consumption. The stricter requirements aim to avoid manufacturers simply adding more batteries to increase range and so encourage energy saving and emissions reductions.
Cui Dongshu is secretary-general of the passenger vehicle market sub-committee at the Chinese Automobile Dealers Association. He has said that tiered car or consumption taxes could encourage the use of lighter and more efficient cars, and so promote the development of technologies for reducing car weight.
Alongside manufacturers and policy-makers, consumers too can play their part. Ding Shanshan said they are still mainly focused on price, range and smart features – but lack knowledge about lifetime carbon emissions.
More information disclosure on carbon footprints would allow consumers to check emissions and supply chain environmental performance and make greener choices. That in turn, would encourage firms to keep improving their products and supply chain management – and stop EVs just getting bigger and bigger.
This article was originally published on Dialogue Earth under a Creative Commons licence.
