Manufacturing method of secondary batteries

Abstract

To easily and reliably transport electrode plates in a manufacturing process of a nickel-hydrogen storage cell.SOLUTION: A nickel-hydrogen storage cell 1 comprises a cathode plate 2. The cathode plate comprises a cathode current collector 21, which is made of a rectangular plate-shaped porous metal, and a cathode mixture layer 22, which contains a cathode active material and is filled into the cathode current collector. There is a filling density difference such that the density of the cathode mixture layer 22 filled into the cathode current collector 21 gradually decreases from a dense surface 22c to a sparse surface 22a. When the cathode plate 2 is divided into three equal parts of a first layer L1, a second layer L2 and a third layer L3 in the direction of thickness from the sparse surface 22a, the first layer and the third layer each have a filling density difference of the active material from 2% to 10% inclusive relative to the second layer L2.SELECTED DRAWING: Figure 9

Claims

1. The device comprises a positive electrode plate having a positive electrode current collector made of a plate-shaped porous metal and a positive electrode composite layer containing a positive electrode active material filled in the positive electrode current collector, a negative electrode plate, and a separator. The reference coating width Ws in the width direction perpendicular to the coating direction on one surface of each positive electrode composite layer is configured to be narrower than the coating width Wp in the width direction on the other surface of the positive electrode composite layer. A method for manufacturing a secondary battery having a packing density difference in which the packing density of the positive electrode active material on one surface of each positive electrode composite layer is greater than the packing density of the positive electrode active material on the other surface of the positive electrode composite layer, The process includes a coating step of applying a positive electrode composite paste containing a solvent for forming a positive electrode composite layer to the other surface of the positive electrode current collector, A method for manufacturing a secondary battery, characterized in that, in the coating step, the positive electrode composite paste does not fall off the positive electrode current collector due to gravity, and the packing density of the positive electrode active material in the positive electrode composite paste is adjusted by gravity so that the lower vertical part is higher than the upper vertical part by a predetermined packing density difference.

2. The method for manufacturing a secondary battery according to claim 1, characterized in that the reference coating width Ws on the surface side of one positive electrode composite layer, which has a high packing density of positive electrode active material, and the width Wv1 of the uncoated portion between the coated end of the one positive electrode composite layer and the inner surface of the peripheral edge in the short-side direction of the positive electrode current collector are adjusted so that Wv1 / Ws ≥ 0.

005.

3. A method for manufacturing a secondary battery according to claim 1 or 2, characterized in that it includes a transport step of using a vacuum suction device to pick up and transport the uppermost positive electrode plate, which is vertically above on which a plurality of positive electrode plates are stacked and placed.

4. The method for manufacturing a secondary battery according to claim 3, characterized in that the transport step involves placing the positive electrode plate such that the upper surface of the positive electrode plate vertically above becomes a rough surface in which the packing density of the positive electrode active material in the positive electrode composite layer is low, and transporting the rough surface by adsorption from vertically above using the vacuum adsorption device.

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