Lithium-ion batteries now play a crucial role in many areas of digital life and will help pave the road to electromobility. When it comes to high-performance energy storage, there is no way around lithium and other rare earths. A sustainable value chain means that the batteries are recycled – but this is not without risk: Even with fully discharged batteries, there is always a residual risk of ignition or explosion. In addition, highly toxic substances are produced during recycling, such as the extremely corrosive hydrofluoric acid.
Gas-tight processes protect employees and the environment
Therefore, getting official approval for the test center to conduct shredding tests with lithium-ion batteries was not a simple process, as Steffen Hinderer, Director Process Development at BHS-Sonthofen, explains: “At the beginning, it was far from clear as to what hazardous substances were produced and what the composition of the waste gases produced during the process was. Of course, we paid meticulous attention to safety and coordinated every single test with the authorities.”
To guarantee the safety of the test facility and protect employees, BHS-Sonthofen developed a sophisticated safety concept in cooperation with TÜV Süd and the approved monitoring body: First, BHS checks whether the batteries to be shredded have been actually exhaustively discharged. Both BHS shredders used – the rotary shear (type VR) for primary shredding and the universal shredder (type NGU) for the main shredding of the material – have a gas-tight design and are flooded with nitrogen. This reduces the risk of explosions and fires. Sensors in the crushers monitor the entire process. In the event of a sudden increase in pressure or temperature in the machine, the control system automatically stops the shredding process. In the event of a fire, the machines can also be completely flooded with water.
Together with TÜV and the approved monitoring body (ZÜS) for safe recycling tests
BHS also pays meticulous attention to protecting people and the environment when storing and transporting the shredded battery material. The crushed batteries are discharged directly into UN-certified drums; a hydraulic slide system prevents possible contamination of the environment. It goes without saying that all employees are equipped with personal protective equipment (PPE) and that the plant fire department was present at every test. To ensure that the safety standard remains at this high level, the approved monitoring body will carry out checks once a year and will scrutinize any adjustments made to the procedure, as might be the case if BHS should carry out tests with solid batteries in the future.