First cheap EV with semi solid-state battery to cost $15,000 as BMW and Mercedes suppliers start pilot cell production too

Solid-state batteries and their commercialized version with 95% solid electrolyte are slowly moving from the R&D or prototype realms into factory lines and real production vehicles ahead of the industry's self-imposed 2027 schedule.

This is when Toyota, Samsung, CATL, BYD and others have pledged to bring electric vehicles with solid-state cells to the market. The transitional technology with 95% solid and only 5% liquid electrolyte, however, or the so-called semi solid-state battery, is already in production electric cars.

At first, it was reserved only for premium electric vehicles like the NIO ET9 sedan that covered 650 miles on a charge with 150 kWh of semi solid-state cells. The battery with 95% solid electrolyte was developed by NIO via a startup called WeLion as battery juggernaut CATL balked at the prospect saying it will be too expensive.

Indeed, it was, as NIO's chief said that the 150 kWh battery pack with nearly solid electrolyte costs as much as one of its cheaper cars. That is why NIO decided to simply rent the battery for longer summer vacation trips, taking advantage of its automatic battery swap technology that is now seeing 100,000 daily swaps taking only a few minutes.

Since then, however, economies of scale have allowed the price of such cells to plunge and has made them economical to include in mass market electric vehicles. The MG4 hatch that will be announced on August 5, for instance, will be the first cheap electric car with semi solid-state battery considering its $15,000 pricing for the top range in China.

The QingTao Energy battery offer a nearly solid electrolyte with only 5% flammable liquid component, making it safer than current commercialized lithium batteries with all-liquid electrolytes. The MG4's 70 kWh battery pack has already undergone the required shock, puncture, and thermal runaway testing, and MG says that its chemistry brings 14% better capacity retention in cold weather, increasing the vehicle range in subzero temperatures.

Meanwhile, both BMW and Mercedes subsidiaries announced mass production plans for solid-state batteries or cells with 95% solid electrolyte. Svolt, which will supply an affordable semi solid-state battery for the next generation BMW Mini, will start trial production next quarter, while Farasis Energy, which is backed by Mercedes, will start a pilot line for manufacturing sulfide solid-state batteries.

Mercedes was the first to integrate a solid-state battery into a production EV platform, too, as it retrofitted the EQS sports sedan with a pack that allows it to cover 620 miles on a charge. The solid-state battery in the Mercedes EQS fits 25% higher energy density in the footprint of the old pack, but Mercedes stayed mum on how much did the undertaking cost.

The world's largest battery maker CATL is of the opinion that true solid-state batteries will only start appearing in mass market vehicles after 2030, but says that cells with 95% solid electrolyte have the potential to serve as a transitional technology and fill the gap until then. As so often happens, CATL's predictions are being proven correct, as the launch of the first affordable electric car with semi solid-state battery would attest.