New battery concepts: the solid state battery

The battery concepts currently used in consumer electronics or electric vehicles seem to have reached the limits of their capacity and offer only limited remaining development options. However the next generation in battery production is already straining at the bit in the form of solid state batteries. It has the potential to overcome numerous restrictions of current battery technology and decisively expedite mobile energy supply in many areas.

No matter whether we are talking about the energy supply for consumer electronics such as smartphones, smartwatches and tablets or electrical vehicles such as cars, e-bikes or e-rollers, so-called lithium ion batteries are used in almost all applications. They store large quantities of energy in a relatively small space and survive many charging cycles without their capacity declining noticeably. The continuous further development and optimization of lithium ion technology has brought this type of battery to the limits of its capacity. High energy densities and the mode of operation using liquid combustible electrolytes require a great deal of effort for cooling and safety installations. The development potential for even higher energy densities and further miniaturization appears to be exhausted. Consequently, the automotive industry and electronics manufacturers are on the lookout for new battery concepts.

One of the most promising battery concepts is the solid state battery, also known as the solid electrolyte battery or solid state accumulator. Research is being conducted into this type of battery worldwide. The first solid state batteries are already available and there no longer appear to be any fundamental technical problems blocking their use in the mass market.

The decisive difference from the lithium ion battery is that in the solid state battery the electrolytes are solid, not liquid. The task of the electrolytes is to conduct the ions between the cathode and anode. The entire battery, with its electrodes and electrolytes, is made of solid materials. Materials like plastic polymers, glass or ceramics can be used as solid electrolytes. Anodes and cathodes are electrochemically bound to the electrolytes via polymer ceramic compounds. This improves charge transfer and reduces the internal resistance of the battery.

Using solid electrolytes saves on space and weight Since this requires far less elaborate design for cooling and battery safety, solid state batteries are lighter, more compact and easier to produce. Far more electrical energy can be stored in the same space. The energy density of solid state batteries is much greater than that of a lithium ion battery with liquid electrolytes. Batteries can be realized in a very thin design and are easy to miniaturize. These characteristics mean the battery type is not only of interest for the automotive industry, but also for consumer electronics and smart devices. Thanks to the absence of liquid electrolytes, solid state batteries are fire-proof and scarcely combustible. As a result, solid state batteries are regarded as more reliable, have longer lives and are safer than lithium ion batteries. Other advantages of solid state batteries are their good storage characteristics and the low dependence of the power on temperature.

Intensive research is still being conducted worldwide into solid state batteries. Automotive manufacturers are above all expediting the development of solid state batteries. The development laboratories are concentrating on the materials and material combinations to be used for the electrodes and electrolytes. Finding the best possible solution for energy density, safety, power density, service life and manufacturing costs is the aim. Even if solid state batteries are already available, most analysts and manufacturers do not expect them to be ready for the market before 2025.

 

Apart from solid state batteries, other battery concepts are being researched, such as magnesium batteries or lithium-air batteries. While some basic technical hurdles still have to be overcome for other technologies, suitability for the mass market is imminent for solid state batteries. Low space requirements, greater energy density and greater safety will make a decisive contribution to promoting energy supply in electronic devices and electric vehicles. The high degree of miniaturization of these batteries opens up new possibilities for electronic gadgets and smart devices, such as smartwatches, fitness trackers, earbuds or smart rings.