24.06.2024
Source: Energy & Management Powernews
Solid-state batteries offer many advantages over lithium-ion batteries. One major disadvantage is the lack of a scalable production method. Fraunhofer researchers want to change that.
Solid-state batteries have significant advantages when compared to the lithium-ion batteries used in electric cars or laptops. As they do not have a liquid electrolyte that can leak and ignite, solid-state batteries are safer and non-flammable. They also have a higher energy density and a longer service life. The drawback: Until now, these batteries with a ceramic electrolyte layer have only been produced on a laboratory scale. Researchers at the Fraunhofer Institute for Manufacturing Engineering and Automation IPA are working on automating this step.
Now they are presenting their successful result, as Jonas Heldt explains. "We were able to raise the production of solid-state batteries from laboratory scale to an industrial, scalable level," says the scientist at Fraunhofer IPA
The researchers' work was part of the recently completed project "Research into new mixing and sintering technologies for graded ceramic solid-state electrolytes" - "EMSiG" for short. The researchers carried out their work together with the medium-sized companies "Dr. Fritsch Sondermaschinen GmbH" and "Dr. Fritsch GmbH & Co. KG". The state of Baden-Württemberg funded the project with over 1 million euros.
About the production process: Traditionally, films are coated so that they serve as anode, cathode and neutral intermediate layer, and then assembled to form the battery. For ceramics, however, powder is used as the starting material. In order to bring this into a solid form, it must be sintered - i.e. heated under pressure. This is where the research team's work began. They investigated various processes.
The most promising process they identified was one in which the powders are stacked dry in a mold. In addition to the cathode, anode and electrolyte layers, the team introduced intermediate layers to prevent the electrolyte content from increasing too abruptly. The researchers want to use these gradual transitions to reduce mechanical stresses and improve contact resistances in the sintered battery.
The filled mold was placed in a sintering press. In this process, the materials are pressed together with a stamp under high pressure and comparatively low temperatures. Instead of the hours required for conventional sintering processes, this only takes a few minutes. Heldt: "Using this process, several graded layers of cathode and separator can be produced in a single manufacturing step." This procedure significantly reduces the amount of work involved and allows subsequent scaling up to larger throughputs. "The foundation has therefore been laid for the industrial production of solid-state batteries," said Fraunhofer in a press release.
Raw materials as a bottleneck
In addition to industry-oriented production processes, a secure supply of raw materials is also a basic prerequisite for the market launch of solid-state batteries. The problem is that the raw materials required for this have not yet been used industrially and are therefore not produced in large quantities. In the case of the Emsig project, this was the solid-state electrolyte lithium aluminum titanium phosphate, or "LATP" for short.
The project partner Dr. Fritsch GmbH & Co KG analyzed the market situation for this. The focus was on where the necessary raw materials could be sourced and in what form they would have to be processed. "The challenge here is not the availability of the individual raw materials per se, but the still relatively small number of manufacturers who use them to produce the solid-state electrolyte LATP," explains Elke Ade. However, the Head of the Metal Powder Division assumes that experience shows that their number will grow rapidly in line with demand for the end product.
Author: Davina Spohn
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