Method for testing at least one battery cell stack with regard to the position of battery cell layers

A method for testing a battery cell stack of at least two battery cells, each of the at least two battery cells comprising an electrode designed as an anode, an electrode designed as a cathode and at least one separator as different types of plate-shaped battery cell layers, the separator being arranged between the electrodes, and each of the different types of plate-shaped battery cell layers having polygonal surface areas of different sizes and each of the different types of plate-shaped battery cell layers are stacked in a direction perpendicular to the surface areas, the method comprising:

• determining, in a first test step, the positions of the plate-shaped battery cell layers of each of the at least two battery cells and checking whether edges of the plate-shaped battery cell layers of each of the at least two battery cells are within a first tolerance range, wherein when the plate-shaped battery cell layers of the at least two battery cells are within the first tolerance range, the at least two battery cells are determined to be usable battery cells;
• stacking the at least two battery cells determined to be usable battery cells in the first step to make the battery cell stack;
• irradiating, in a second test step, the battery cell stack via X-rays emitted by an X-ray emitter and detecting the emitted X-rays via an X-ray detector, the X-rays being directed substantially perpendicular with respect to the surface areas of the plate-shaped battery cell layers;
• and
• determining, via the detected X-rays, the positions of edges that delimit at least two corners of plate-shaped battery cell layers of a selected type of the different types of plate-shaped battery cell layers, and checking whether a greatest distance determined between the edges of all of the plate-shaped battery cell layers of the selected type is within a second tolerance range, wherein when the greatest distance determined between the edges of all of the plate-shaped battery cell layers of the selected type is within the second tolerance range, the battery cell stack is determined to be a usable battery cell stack.