About the application
Electrolyte filling is a critical stage in the EV battery manufacturing process. During this phase, the battery cells are filled with the electrolyte under vacuum through a high-precision dosing needle. Since the electrolyte reacts with water, forming corrosive products, the ambient air must be very dry during filling. The machine is notably large and features several guards that provide access to different sections.
The challenge
There is a risk of electrolyte leakage, and operators may need to inspect and maintain the machine. When doing so, it is important to reduce the risk of entrapment either by preventing the doors from closing or by having an escape release. However, in this case drilling a hole to fit an escape release could potentially lead to leakage of dangerous gases.
Due to the release of flammable chemicals in this ATEX environment, products compatible with explosive atmospheres are needed. Moreover, contamination with ferrous metals can cause defects and influence battery performance, therefore copper-free and zinc-free components are required.
The solution
Fortress developed a trapped key system to allow access to 13 sections of the electrolyte filling machine. Enforcing a predetermined sequence of events ensures access to personnel only after the machine has come to a controlled stop. Stainless steel interlocks are mounted on each access point. Personnel keys prevent operators from being trapped and offer additional protection against unexpected start-up.
Step by step process
Why trapped keys and stainless steel?
Trapped key systems are very versatile and allow the enforcement of a predetermined sequence of events. In this case, until all the keys are returned in their original position the machine cannot restart.
The stainless-steel interlocks used are:
✅ compatible with the corrosive environment of this stage of battery manufacturing
✅ free from zinc and copper, reducing the risk of contamination
✅ mechanical and do not require wiring
In addition, the use of personnel keys provides an additional level of protection to reduce the risk of entrapment and unexpected start-up.
Alternative solutions
This solution successfully resolved a challenge for a specific customer based in China. Fortress can accommodate alternative setups and/or multi-range options. Share your application details with us so we can design a bespoke solution to meet your needs.
