22 May 2024
High-performance batteries that charge quickly, have a long service life and at the same time guarantee a high energy density. This is the aim of the Franco-German joint project HiPoBat - High Power Batteries, which was launched at the beginning of May and is funded by the German Federal Ministry of Education and Research. The focus is on the development of high-performance solid-state batteries that can reduce the ecological, geopolitical and economic pressure in the field of electrochemical energy storage. The project which is coordinated by Forschungszentrum Jülich will run for three years.
Energy density and power density are important properties of batteries. Energy density indicates how long a battery can be used before it needs to be recharged. Power density, in contrast, is a measure of how quickly a battery can provide and release energy. A general difficulty lies in combining high power density with a suitable energy density.
High-performance batteries have various areas of application. In electromobility, for example, they could offer an alternative to batteries with ever-increasing energy densities. Electric cars might then only have a range of 300 kilometres, but could be recharged in less than 10 minutes. They can also be used as a small battery in hybrid vehicles to support the internal combustion engine while accelerating and to recover energy while braking. They are also indispensable for cordless power tools. In addition, they are required for many load distribution applications in stationary operation, for example for uninterruptible power supplies. These provide power during blackouts and voltage dips and are important for maintaining computer storage systems, industrial processes, communications, vital systems, security systems, and the stabilization of power grids.
All of these applications require a sufficient energy density coupled with high performance in both charging and discharging modes - a dilemma that the German and French scientists are aiming to overcome in the collaborative project. In particular, they are investigating how ions and electrons behave in the battery during charging and discharging and how the cells heat up in the process. The state of the art of current lithium-ion and sodium-ion technology with liquid electrolytes is considered as a reference. New materials, new cell designs, and a better understanding of the ageing process of batteries should enable the development of high-performance lithium and sodium-based solid-state batteries.
In addition to the intrinsic properties of the materials, such as the ionic and electronic conductivity and the shape and size of the particles, the design of the electrodes also plays a crucial role in the final performance of the battery. In particular, multi-scale modelling approaches, adapted manufacturing processes, and 3D microscopic methods are used for this purpose.
The focus is also on the availability of resources. Many raw materials in conventional batteries are imported from problematic countries. The desire for technological sovereignty and sustainability has led to increased interest in sodium batteries in particular. Sodium is a common element that is contained in table salt, for example. A technology that does not use cobalt, nickel, graphite, or lithium would protect the environment, reduce the pressure on policymakers, and strengthen the Franco-German economy.
