Method for the manufacture of contacts between electrochemically active discs and interconnectors in high temperature fuel cells

A method for the manufacture of contacts between electrochemically active discs and interconnectors in planar high temperature fuel cells the interconnectors of which have air-side and gas-side surface profiles with contact surfaces on raised portions, with the raised portions of each surface profile having the contact surfaces approximately spanning a plane and with deviations in this arrangement lying within a predetermined tolerance, in which method a layer is applied onto the electrodes of the electrochemically active discs, with the layer consisting of a contact mixture which contains electrically conductive particles and a medium embedding the particles, the surface profiles or the electrodes are brought into contact with the applied layer at a working temperature so that the raised portions penetrate into this layer and thus connections are formed between the contact surfaces and the electrically conductive particles and thus discrete homogeneously structured connections are formed between the contact surfaces and the electrodes, and finally the medium embedding the particles is removed under thermal part treatments and the discrete connections are solidified, wherein the medium embedding the particles is a hot melting composition which is solid at room temperature and wherein, at the said working temperature, the hot melting composition is in a liquid or plastic state,

• wherein the medium embedding the particles is applied to the electrode at or above the working temperature and then brought to a solidifying temperature to solidify the hot melting composition, or is applied as a solidified foil between the electrodes and the raised portions, and
• wherein the applied layer or foil is subsequently heated to said working temperature to form the discrete homogeneously structured connections,
• wherein the interconnectors and the electrochemically active discs are assembled into a stack in an alternating arrangement and along a stacking axis, with this stack being uniformly heated in an assembly apparatus to the working temperature;
• wherein from a follow-up clamping of the assembly apparatus, which uniformly exerts a constant or variable pressing force in the direction of a stack axis, the discrete connections are produced with a reduction of the stack height by 3 to 10%, and wherein finally the hot melting composition is thermally removed.