Charge faster, drive longer Franco-German research collaboration develops fast-charging batteries
High-performance batteries that can be charged quickly, have a long service life and at the same time guarantee a sufficiently high energy density – this is the aim of the Franco-German HiPoBat High Power Batteries research project, in which the Institute for Particle Technology at Technische Universität Braunschweig is involved. The focus is on the development of high-performance solid-state batteries that can reduce the ecological, geopolitical and economic pressures in the field of electrochemical energy storage.
Energy density and power density are important characteristics of batteries. Energy density indicates how long a battery can be used before it needs to be recharged. Power density, on the other hand, is a measure of how quickly a battery can supply and release energy. A common difficulty is to combine high power density with sufficient energy density.
Various applications
In electromobility, for example, high-performance batteries could offer an alternative to batteries with ever-increasing energy densities. At the current stage of development, electric cars would have a range of only 300 kilometres, but could be recharged in less than ten minutes. They can also be used as a small battery in hybrid vehicles to assist the internal combustion engine during acceleration and recover energy during braking.
They are also essential for cordless power tools. In addition, they are required for many stationary power distribution applications, such as uninterruptible power supplies. These provide power during blackouts and brownouts and are essential for maintaining computer storage systems, industrial processes, communications and security systems, vital medical systems and power grid stabilisation.
All these applications require sufficient energy density combined with high performance in charging and discharging – a problem that the German and French scientists aim to solve in the joint project. In particular, they are investigating how the ions and electrons in the battery behave during charging and discharging, and how the cells heat up in the process. The state of the art in current lithium-ion and sodium-ion liquid electrolyte technology will be used as a reference. New materials, new cell concepts and a better understanding of the ageing process of batteries should enable the development of high performance solid-state batteries based on lithium and sodium.
Another focus is the availability of resources. Many raw materials for 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 found in table salt, for example. A technology that works without cobalt, nickel, graphite or lithium would protect the environment, reduce pressure on politicians and strengthen the Franco-German economy.
Fields of activity of the Institute for Particle Technology (IPAT) at TU Braunschweig
On the one hand, the Institute for Particle Technology is focusing on the design of the 3D electrode structure with the aim of enabling fast charging and long life with sufficiently high energy density. To this end, the synthesis, formulation and process optimisation of silicon composites are being investigated. This is seen as an industrially relevant, low-cost, high-capacity anode material for lithium- and sodium-based solid-state systems.
IPAT will also compare and evaluate different processing routes in order to develop an efficient and scalable process route for the production of silicon-based anodes. In addition, IPAT will transfer process techniques from lithium-based solid-state batteries to sodium-based solid-state batteries in order to better understand the new sodium battery system and its interactions during production.
All experiments will be accompanied by simulations. This means that new discrete element models of the production processes for lithium- and sodium-based systems are being developed, which will map the production steps virtually. These will be used to support process optimisation for anode production. These models will be used to model the microstructure of the electrodes during the manufacturing process, which can then be used to simulate the electrochemical properties of the battery. All models developed will accompany the production process as a “digital twin” (virtual representation of the processes using real-time data).
Project data:
Funded by the German Federal Ministry of Education and Research (BMBF) and coordinated by Forschungszentrum Jülich, the project will run from May 2024 to April 2027 and has a total budget of €17.3 million.