Mercedes-Benz Tests Prototype Solid State EV Battery In EQS, Gets 1,000 KM Range

New prototype solid-state EV battery pack developed by Mercedes-Benz and partners Factorial Energy (Factorial) pictured.

Arguably touted as the ‘holy grail’ of electric vehicle (EV) battery tech, solid state EV battery promise both higher density and greater safety versus lithium-ion types – the latter is commonly in use today. However, solid state EV battery tech remains largely limited as it is not in mass production yet.

That could change following recent tests and overwhelmingly positive results charted by luxury marque Mercedes-Benz with this tech. Said test saw the three-point star use a “slightly modified” version of its EQS flagship EV sedan model fitted with a prototype solid state battery pack.

The prototype solid-state EV battery pictured up top was recently adapted into and tested in a EQS - the three-point star's flagship EV sedan model.

The EQS prototype pictured adopts a lithium-metal solid-state battery pack designed and engineered by the Mercedes‑Benz Center of Competence for Battery Systems and the Mercedes AMG High Performance Powertrains (HPP) subsidiaries.

It also uses cells co-developed with and supplied by Factorial Energy (Factorial) – an American start-up that the automaker actively collaborates to develop EV tech with – and a floating cell carrier.

The prototype lithium-metal solid-state EV battery pack uses cells co-developed and supplied by Factorial, and it features a floating cell carrier.

“When the battery charges, the materials expand, and when it discharges, it contracts. Supporting which are pneumatic actuators that interact with the cell volume change during charging and discharging, which affects the battery’s performance and lifespan,” Mercedes-Benz detailed.

The automaker continued by noting that the prototype solid-state EV battery pack used in this test also adopts solid electrolyte instead of liquid-type. This, according to them, enhances cell safety and enables the adoption of new anodes such as lithium metal.

In turn, this has the potential to increase gravimetric energy density in EV battery packs by up to 450 wH/KG, thus paving the way for even lighter and more compact battery packs.

A closer look at the 'slightly modified' Mercedes-Benz EQS used to test out the prototype new solid-state EV battery pack detailed.

In the case of the EQS tester pictured, the prototype pack it used enabled up 1,000 KM in range, which is 25% more than what the regular model equipped with a 118 kWh  lithium-ion battery pack can yield – a maximum of 800 KM is touted from the EQS 450+ variant.

Looking ahead, more tests are being planned for the prototype solid-state EV battery pack detailed over the coming months.

“Being the first to successfully integrate lithium metal solid-state batteries into a production vehicle platform marks a historic achievement in electric mobility,” says Siyu Huang, CEO of Factorial Energy. 

Real world tests sees the solid-state EV battery pack grant the EQS with up to 1,000 KM range out of the box.

The exec adds this breakthrough demonstrates that solid-state EV battery have indeed moved beyond the laboratory towards real-world application. Huang even notes how this tech could also set to new benchmarks for the entire industry.

“Developing an automotive-scale solid-state battery underlines our commitment to innovation and sustainability,” added Markus Schäfer, Mercedes-Benz’ CTO, who also echoed Huang’s sentiments mentioned earlier.