Does solid-state battery technology have potential?
Higher, faster, but in the case of e-cars mainly further is the goal of many pilot projects and researchers. The race for higher ranges of electric vehicles has long been underway. For example, there are concept cars like the Vision EQXX from Mercedes that can already boast a range of over 1000 kilometres. And these distances should be normal.
It seems logical to start with the vehicle's storage medium, the car battery. However, new battery technology is a highly complex topic. That's why we asked the Fraunhofer Institute for Material and Beam Technology IWS and were able to win Dr. rer. nat. Holger Althues, Head of Department Chemical Surface and Battery Technology as an expert. Umschalten.de asked: What is a solid-state battery anyway? What are the differences to conventional car batteries and when can private consumers also expect solid-state batteries in their e-cars?
Table of contents
What is a solid state battery and how does it work?
First of all, the term "solid battery" is an umbrella term for batteries that use a solid as an ion conductor between the cathode and anode instead of a liquid electrolyte, i.e. conducting salt, dissolved in a solvent. Different types of these solid electrolytes are distinguished here, which in turn can be used with different storage materials. So there are different approaches in research, some of which differ greatly in their respective characteristics. In a solid battery, a solid material takes over the ion conduction between the positive and negative electrode. The storage mechanisms can be adopted from other batteries, so they function in the same way. The challenge is therefore not so much the idea itself, but the implementation.
Solid state battery Advantages and differences to conventional batteries
The use of solid electrolytes results in some special features and new possibilities:
By using solid electrolytes, manufacturers save space and weight. In addition, the flammability/ignitability decreases compared to the volatile organic solvents in conventional electrolytes. In some cases, the flammability of solid electrolytes can even be zero. This can increase safety when used in series production. While we now know that there is no increased fire risk with e-cars, improving passenger safety is always a positive development. By requiring less cooling and safety equipment thanks to increased safety, manufacturers make everything more compact and lighter. This in turn has an impact on fuel consumption and range. Furthermore, it is hoped that solid electrolytes will make new storage materials and concepts possible. In particular, the use of a lithium metal anode (instead of conventional graphite anodes) would bring about a significant increase in energy density (stored energy per kg or litre of battery). With liquid electrolytes, the lithium metal anode could not be used safely and stably enough until now. In concrete terms, according to Dr Althues, this means an increase in range of up to 50%! The Fraunhofer Institute is actively researching this field and sees lithium metal anodes as a "key element for the battery systems of the future".
What are the challenges in implementing solid-state batteries?
The principle of the solid-state battery seems to be quite simple, but why is it not yet available in series production? The biggest challenge is clearly the processing or production. For the battery to work, the electrolyte must be finely distributed and brought together with the other cell components. Whereas this is quite simple for batteries with liquid electrolytes, which are simply "filled" with the electrolyte afterwards, thus automatically wetting all interstices and interfaces, this process is very time-consuming and complex for solid electrolytes. New processing methods must therefore be developed for the serial use of solid-state batteries.
In addition to the challenges of manufacturing materials, components and cells, stable interfaces between the cell components (especially between electrodes and electrolyte) are of great importance. Current research is dedicated to these issues and special coatings of the lithium metal anode, respectively the cathode materials are promising solutions
When will the solid-state battery come as standard?
Although certain variants of the solid-state battery have already been tested in vehicle applications, many manufacturers and experts do not expect it to be ready for the market until 2025. Our expert Dr Althues does not expect widespread use before 5-10 years. If you are waiting for the solid-state battery mainly because of the increased range, we still have good news. In research, even apart from the solid-state battery, there are many approaches and pilot projects, such as inductive charging, that are addressing the issue of range.
Solid-state battery: Sustainable car batteries at last?
The question of sustainability is always important. For solid-state batteries, it cannot yet be answered holistically. Research is still searching for the ideal combination of electrolyte and anode. Depending on which materials prevail, the sustainability rating will be accordingly better or worse. Since the solid-state battery is similar to the lithium-ion battery in many respects, recycling concepts can possibly be transferred. If, for example, the Fraunhofer Institute's lithium-sulphur battery were to prevail, the result would be a significantly reduced need for raw materials and the battery would thus be much more sustainable.
Fraunhofer IWS researches: The lithium-sulfur battery
For their research project "SoLiS - Development of Lithium-Sulphur Solid State Batteries in Multilayer Pouch Cells", the Fraunhofer Institute IWS relies entirely on sulphur as a material. This is characterised by a particularly high storage capacity and low material costs and thus enables the construction of very light and cost-effective solid-state batteries. The project is funded by the Federal Ministry of Education and Research (BMBF) with a total of almost 1.8 million euros. In addition to electromobility in the sense of e-cars, the research results could enable applications in electric aviation, for example. If you want to know more about the topic, it is worth visiting the website of the Fraunhofer Institute IWS.
Solid-state batteries: Promising and promising for the future!
It is not without reason that the topic of solid-state batteries is on everyone's lips. In addition to increased safety and possibly more sustainable production depending on the material used, it is above all the range increase of up to 50% that raises hopes among us e-car drivers. The principle is very simple and comparable to a conventional lithium-ion battery. The only problem, and unfortunately it is not a small one, is mass production and manufacturing. It will probably be another 5-10 years before we have a solid-state battery in our own e-car. But it's nice to know that research in the field, such as the SoLiS research project of the Fraunhofer Institute IWS, is in full swing. We are already looking forward to future developments in the electromobility market!
If you have any questions about this topic or electromobility in general, please contact us at firstname.lastname@example.org!
We would like to thank Dr. Althues and the Fraunhofer Institute IWS very much for the good cooperation and their expertise.