Mercedes-Benz, solid-state battery technology from the perspective of car companies

When searching for information about solid-state batteries recently, Hansen Chang, a team leader of Mercedes-Benz's solid-state research group, mainly introduced some of Mercedes-Benz's views on solid-state batteries at the research level. This can be compared with another German luxury car company, BMW. The common feature of the two luxury car companies is that they are both planning the next generation of research (RD In-house):

● Mercedes Benz

It is exploring the construction of a super battery factory in Europe with Stellantis, and will subsequently invest in ACC, a subsidiary of Stellantis. It aims to promote the research and development and reserve of next-generation batteries; solid-state batteries mainly invest in Prologis and Factorial Energy, and are currently jointly developing next-generation solid-state batteries through these two partnerships; it also invests heavily in battery anode materials, striving to achieve high energy density and improve fast charging speed.

● BMW

The strategy is very clear. It has begun to turn to cylindrical batteries and is the only European car company that has not built a battery factory (but has built a large-scale battery pilot line). Solid-state batteries have been developed through investment in SolidPower and the cooperation with SolidPower is currently being deepened. It plans to install and test the batteries in 2022, launch a solid-state battery prototype before 2025, and use it in mass-produced vehicles before 2030.

▲Figure 1. Battery layout of two German luxury car companies

Part 1. Mercedes-Benz’s judgment on cutting-edge batteries

According to the evolution of power batteries for electric vehicles, the current level in 2022 is about 500-700Wh/L. The energy density of cutting-edge high-energy density batteries is 700Wh/L. Starting from the traditional standardized (Lib standard) power batteries, it will gradually enter the cutting-edge batteries (Post LiB) and by 2030 it will be able to reach 1,000Wh/L, achieving higher energy density batteries.

This data is the volume energy density Vol Energy Density obtained under 25 degrees and 1/3C test conditions.

▲Figure 2. Mercedes-Benz’s estimation of battery energy density evolution trend

In the future, Mercedes-Benz will develop solid electrolyte materials that are safer and have a higher energy density than conventional lithium-ion battery technology. When used instead of highly flammable organic electrolytes, safety and stability will be improved, making the use of high energy density materials possible.

Compared with current lithium batteries, solid-state batteries using sulfide electrolytes are superior in terms of safety and other aspects. Polymer batteries are suitable for power type batteries (suitable for high rates). The advantages of oxide electrolyte batteries are high safety and high energy density at high temperatures. Sulfide electrolyte solid-state batteries are expected to be used in the automotive field, but there are still some problems to be solved.

At present, Mercedes-Benz is still mainly in the research stage, and solid-state battery technology is framed in the research and reserve field.

▲Figure 3. Routes of different solid electrolytes

In Mercedes-Benz's view, solid-state batteries have the following strategic value:

● Increase energy density and improve safety

● Differentiate between different vehicles (high-end models)

● In house ASSB R&D, developing materials and battery prototypes

▲Figure 4. Mercedes-Benz's solid-state battery DNA

Part 2: Prospects of solid-state batteries

At present, solid-state batteries have been developed for many years. Although many companies have announced a lot of investment, they are still in the initial stage. With the listing of European and American solid-state battery start-ups, in the past year, they have not reached a state where they can be put on the car and take on the heavy responsibility. Therefore, these startups and car companies are currently planning to commercialize the batteries (initial installation on the car) before 2025.

From the perspective of the car companies we cooperate with, even though the commercial preparation of solid-state batteries will start in 2025 (at this point, car companies may pay a relatively high battery price), I think that during the period of 2025-2030, the focus will still be on the progress of some luxury car companies, who need to increase the volume energy density of batteries and make them lighter. This will help them reduce the curb weight of the entire vehicle and improve the handling of the entire vehicle.

At present, we see that domestic solid-state battery companies need to quickly increase their production capacity because the scale of traditional batteries is already very large, and they need to quickly improve production testing and iteration from small batches. The semi-solid batch has begun to build production capacity from 2GWh to 5GWh.

Summary: As battery cost becomes a topic of great concern, people are more willing to look forward to the low cost performance of sodium batteries. The concept of solid-state batteries for many years has made people begin to doubt it. It may be more appropriate to focus on semi-solid-state batteries (condensed state).