New horizons for the e-car: When will the solid-state battery come?

New horizons for the electric car
When does the solid state battery come out?

The solid state battery is something of a “holy grail” for battery seekers, and therefore also for electric mobility of the future. If there is a breakthrough in this technology, the critical weaknesses of the electric vehicle can be eliminated in one fell swoop. There are even manufacturers who are already talking about an “end game”.

The solid state battery aims to take the e-vehicle to new heights: car manufacturers themselves and their customers promise extremely short charge times, maximum ranges, complete fire safety and lower costs from new battery technology. But the race for the super battery is still open: will it ever come? And if so: when and by what brand?

Recently, Nissan has been making a fuss when it comes to solid state or solid state technology: the Japanese announced in April that they would start trial production from 2024, with the first series cars coming to market in 2028. The group sees itself very advanced in development and is wildly optimistic. Clear. Chief Technology Officer Kazuhiro Doi at least gave reporters an extraordinarily open insight into the plans and state of development in mid-April. The detailed lecture was even more grotesque as other automakers are also making sensational announcements, but so far they have been conspicuously backtracking on the technical details.

Is it really “end game”?

At VW, there is an opinion that the research on the solid-state battery is in the “ultimate game” stage.

(Photo: Volkswagen)

What is clear, however, is that all the major auto manufacturers are working hard on the super battery. Volkswagen’s head of batteries, Frank Blum, has spoken of an “ultimate game” in battery technology that every company wants to win. In this race, the Wolfsburg team works with the American company Quantumscape, where they also own the majority of the shares. The startup is one of the most promising contenders for the solid materials pioneer role. According to previous announcements, the technology should be available as early as 2025, and at least one pilot plant could start production testing.

Bloom talks about increasing the range by 30 percent compared to current lithium-ion batteries, while at the same time the charging time should be halved. Together, they can finally solve the problem of the range of electric cars. No wonder other players like Toyota, Panasonic, BMW, Ford and LG are also in the race. They give the dates between 2025 and 2030 to start.

Solid instead of liquid electrolyte

The difference between a solid-state battery and rechargeable batteries today is only small: instead of a liquid electrolyte, a solid battery is used. The electrolyte is one of the central components in every battery and is responsible for transferring ions between the anode and cathode, which in turn allows electrons to move in the opposite direction, ensuring current flow and ultimately driving the electric motor. Solid state batteries are already used outside of cars, not only in electronics, but also in commercial vehicles and small chain construction. For example, the Mercedes Citaro bus runs on a special type of solid-state battery, which, however, must be pre-heated and therefore not suitable for cars.

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The batteries currently used in Mercedes for cars in the EQ series are good. But Stuttgart residents also want a solid battery.

(Photo: Mercedes)

Simply switching from a liquid to a solid has potential advantages: because while a liquid electrolyte burns as easily and quickly as chemically bound gasoline, its solid counterpart is nearly impossible to ignite. This could be a safety feature, especially in the event of a collision between electronic vehicles. However, this does not mean much, since the current liquid electrolyte batteries for electronic cars are now considered very safe.

Lithium instead of graphite

The point that makes solid technology really interesting is something else. Since the use of a solid electrolyte allows the use of alternative anode materials: instead of the anode being made of graphite, as is common today, it can be made of lithium, for example, which has a much higher electrochemical potential. Its larger specific capacity enables higher power density with the same battery size and ultimately a longer range. A 30 percent stake in the Volkswagen Mann Blume is generally considered unlikely.

Metallic lithium as the anode material is not a new discovery. Researchers have experimented with the active substances for years; However, with regard to the combustible liquid electrolyte, these batteries were highly unsafe for sequential use in vehicles. The reason is poor control of the anode structure with the age of the battery. It dramatically changes its shape over the course of the many charge cycles, resulting in dangerous short circuit fires with liquid electrolytes once the proliferating fingers reach the cathode side. This is not easy with solid electrolytes, but there is also a risk of cell deformation and destruction.

Sulfur-based ceramic as conductor

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Nissan is also keen on developing the solid-state battery.

(Photo: Nissan)

However, a lithium anode is an appropriate approach, at least in research, if stability and safety issues can be resolved. However, in principle, it is also possible to use other combinations of materials. The same applies as is often the case in battery research: if you change a component or requirement, there are many new possible combinations and solutions. Developer Nissan Doi also uses large databases and artificial intelligence to investigate many variations, some of which may have the possibility of serial production. Currently, none of the manufacturers are looking for a clear commitment to the lithium anode. The situation is clearer when it comes to electrolytes: sulfur-containing ceramics should generally predominate there. Above all, it achieves a very high conductivity compared to polymers and phosphate ceramics.

After determining the electrode material and the electrolyte variable, the industry still has to master production. Nissan claims the costs are lower compared to a liquid battery, but there is no practical proof yet. Some other experts predict higher prices for solid state cells.

30 year lead for liquid battery

In the end, it remains to be seen how the price-performance ratio of the new technology will be in its various potential variables in the future. There seems to be a lot possible between use in mass vehicles and exclusive use in luxury cars. The abrupt end of the classic liquid battery is unlikely to mean the launch of the solid battery on the market. After all, the current technology has had a development lead of about 30 years and is not easily catching up: it has proven itself in the car, materials and production processes have been tested and its performance will continue to increase in the coming years.

Overall, the battery range is likely to become more differentiated in the coming years. The scarcity of materials and price fluctuations alone will ensure a wide range of different battery variants. In addition to the classic NMC lithium-ion batteries, inexpensive iron-phosphate batteries already exist, and cheaper sodium batteries may be added soon. And finally, the solid state battery. Which model is offered in which car will primarily depend on the specific requirements and the willingness of customers to pay.

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