Electricity and Control December 2022

MEASUREMENT + INSTRUMENTATION

Digital measurement is key to high quality Li-ion batteries The fast-growing demand for batteries, for applications ranging from powering vehicles to storing energy from renewables, is seeing a rapid increase in the number of new factories being built to produce them. Here, FrenkWithoos for ABB Measurement &Analytics looks at the role that the latest generation of digital measurement equipment can play in helping to ensure the highest levels of quality and consistency in battery production.

W ith countries around the world striving to reach the goal of zero emissions, consumers, manufacturers and governments are looking for ways to replace fossil fuels with sustainable, pollution-free energy sources. A major part of bringing this to reality will be in the availability and use of reliable and efficient battery technologies – for storing energy from renewable sources like wind and solar, providing reserves of power for the grid, and powering transport. Driven largely by the electric vehicle industry, Lithium-ion (Li-ion) batteries have emerged as the frontrunner for many of these applications. Compared to other types of batteries, Li-ion batteries offer a long life, flexibility in material compo sition and the versatility to power a wide range of products, from electronic devices to heavy electric vehicles. From 2015 to 2022, demand from the automotive and transport sectors accounted for 450 GWh of Li-ion battery capacity, and there has been a 921% increase in demand from all sectors over the same time period. The battery industry is ramping up production dramatically to meet this need; China currently dominates, providing more than 76% of global manufacturing capacity, but the rest of the world is catching up fast. Europe plans to have 850 GWh of capacity on stream by 2030 – Germany alone will account for 330 GWh of this total. A battery of processes Li-ion battery cells consist of an anode, a cathode, a sep arator and a liquid electrolyte.

Digital measurement and monitoring in production contributes to top quality batteries. Electrode manufacturing begins with mixing active materials, binders and additives into a slurry. In the next step, the slurry is coated on both sides of the current collectors. These take the form of webs of aluminium, for the cathode, and copper for the anode. The webs move on through a drying section to remove the solvent, which is usually recovered and reused. The copper and aluminium foils are compressed by a pair of rotating rollers in a calendering process, helping to adjust the electrodes’ physical properties such as bonding, conductivity and density. Following a slitting and stamping stage to form the electrodes to the required dimensions, they go through a vacuum drying stage to remove excess water. The electrodes are then sent to the dry room, along with dried separators for cell production. The electrodes and separators are wound or stacked, layer by layer, to form the internal structure of a cell. The final two stages of production involve enclosing the electrodes and separator in the package, sealing them and then filling the package with electrolyte in a dry vacuum environment. Measuring quality Each of these production stages presents particular factors that affect quality, requiring that parameters such as temperature, pressure, force, level, and flow are all measured accurately. For example, slurry mixing is conducted at a temperature of 20 to 40°C, and other quality parameters – including the

Battery cells in production; this entails a complex sequence of processes, whether for smaller or larger units.

18 Electricity + Control DECEMBER 2022