Our stack presses support the technical testing of fuel cell and electrolysis stacks at the end of their production processes.
The pre-assembled stack, which consists of a large number of plates, is first moved into the machine and then compressed to a defined height until a certain pressure is reached within the stack. This pressure must then be maintained unchanged for several hours. At this time, the stack is subjected to all the necessary technical tests carried out by the customer and with the help of further procedures. These are necessary to confirm its full operability. As soon as the tests are completed, the stack is finally assembled with tie rods or tension straps and the finished stack is removed.
In order to be able to guarantee assembly work during operation with maximum safety, we avoid hydraulic drives deliberately. Instead, the stack is compressed inside the press by means of servomotor-driven spindle units. These are operated synchronously and thus enable particularly homogeneous compression of the stack.
A special feature is the compensation of production-related stacking tolerances. Stacking tolerances are unavoidable, but when the stack is compressed, they cause transverse forces which can damage the stack. In order to eliminate these and to build up an even pressure distribution within the stack, these transverse forces must be continuously compensated for during compression of the stack. This is done with short-stroke cylinders that are located under the spindle lifting elements.