By 2035, the sizes and types of cars sold as BEVs will look very much like those sold with combustion engines today. That is the meaning of a statement in the 2026 EV progress report published on March 12, 2026, by ‘clean energy’ pressure group Transport & Environment (T&E), reflecting that they had “assumed that the segment mix within BEV and ICE powertrains would converge by 2035.” If T&E is right, it has profound implications for platform design, thermal systems and cost engineering, writes Peter Donaldson.

For anyone unfamiliar with the jargon of automotive product planning strategy (a group that includes myself) this needs unpacking. ‘Segment mix’ means the sales distribution across vehicle size classes extending, for example, from A-segment minicars (Fiat 500) to E-segment luxury saloons (BMW 5 Series) and the proliferating SUV variants of each.

Today, the BEV and ICE mixes look very different. BEVs are heavily skewed toward larger cars (D- and E-segments) and J-segment SUVs because early adopters could afford higher prices and car manufacturers prioritised profit margins. Small BEVs in the A- and B-segments remain under-represented, accounting for just 24% of BEV sales versus 48% of ICE sales, according to the report’s annex.

Convergence implies that by 2035, consumers will choose a vehicle size based on their needs, instead of one from a larger category because it has their preferred powertrain type. The share of J-segment SUVs, D-segment large cars and A/B-segment small cars will normalise across both powertrains. Price parity across all segments by 2030 (if CO2 targets are safeguarded) and modular EV platforms that scale across segments will drive this normalisation, T&E argues.

One major engineering implication is that the days of a dedicated small-BEV architecture and a separate large-BEV platform are gone. The next generation of platforms must accommodate batteries from 30 to 100 kWh, wheelbases of 2.5 to 3.0 m, and payloads from a city commuter to a seven-seat SUV – all with minimal re-engineering. Shared motor and inverter families across the range will be essential to achieve scale.

Another implication is that thermal management must scale. A cooling system designed for a 150 kW motor in a C-segment car will struggle with a 300 kW motor in an E-segment SUV, but two completely different architectures are not affordable. Variable-flow pumps, smart valve sets and software-defined thermal logic are essential. The same applies to cabin HVAC: a small B-segment BEV has far less frontal area and glasshouse volume than a large SUV, yet both must deliver efficient heating and cooling.

Third, manufacturing flexibility becomes critical. If production lines are optimised only for large vehicles, car makers will be caught out as small BEV volumes rise. Mixed-model assembly capable of switching between, for example, a B-segment hatchback and a D-segment SUV on the same line is no longer a ‘nice-to-have’ option but has become a survival requirement for high-volume producers.

Fourth, cost engineering takes centre stage. Small BEVs cannot rely on large battery margins to hide inefficiencies. Every component from the inverter to the wiring harness to the sealing system must meet aggressive cost targets without compromising quality. The affordable segment promises volume, and volume is what pays for platform investment.

Finally, it is unwise to over-optimise for large vehicles today. The 2025 BEV market may be dominated by premium SUVs, but the 2035 market will look like the 2025 ICE market: a broad mix of small, medium and large cars, together with SUVs. Those who design only for today’s skewed distribution will find their architectures obsolete before the decade ends.

The convergence of segment distributions is not a distant policy prediction – it is a design brief. Manufacturers should build platforms that scale, thermal systems that adapt and cost structures that work for every segment – because the future BEV market will look a lot like the ICE market they might think they have left behind.

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