JPS6125172Y2 - - Google Patents

Description

[Detailed description of the invention] This invention relates to the improvement of current collectors used in alkaline storage batteries such as nickel cadmium, nickel-zinc, etc., and improves the bonding strength between the current collector and the electrode body to increase the internal resistance of the storage battery. This is intended to improve the high rate discharge characteristics.

The electrode body of an alkaline storage battery, such as a nickel-cadmium battery, consists of an anode plate, a cathode plate, and a separator inserted between these plates, and these are wound to form a spiral electrode body, or the separator A plate-like electrode body is formed by stacking the electrode plate groups alternately with the electrodes interposed therebetween.

As for the method of attaching the current collector to each electrode plate, from the viewpoint of improving high-rate discharge characteristics and saving materials, conductive edges of a predetermined electrode plate are made to protrude from the upper and lower end surfaces of the electrode body, respectively, and the conductive edges are attached to the conductive edges, for example. A flat current collector 40 having a folding line 41 perpendicular to the main plane as shown in FIG. 6, or a cut and raised piece 51 as shown in FIG.
A method of electrically welding the current collector 50 with be.

Now, here, in order to reduce the internal resistance of the battery, the current collector needs to be as thick as possible, and on the other hand, the ridge that forms the weld with the conductive edge of the electrode plate is It is preferable that the thickness is small. The reason for this is that the conductive edge of the electrode plate is generally made of a thin plate, so when this conductive edge and a thick protrusion are crossed and electrically welded, there is a difference in heat capacity due to the difference in thickness between the two. This is because if the welding current is set high for the purpose of improving the welding strength, the conductive edge made of a thin plate with a small heat capacity will melt and break, making it impossible to obtain a strong bonding force.

The present invention was developed in view of this point, and the current collector is electrically welded to the conductive edges of the electrode plates protruding from the upper and lower end surfaces of the electrode body, and is made of a material having a thickness smaller than that of the base material constituting the current collector. A nickel plate or a nickel-plated steel plate is used to reduce the internal resistance of the battery and increase the bonding strength between the current collector and the electrode body.

The present invention will be described in detail below along with drawings showing embodiments thereof. 1 is an anode plate, 2 is a cathode plate, and a separator 3 is interposed between these plates to form a spiral electrode body 4 . At this time, the anode plate and the cathode plate are wound with a slight shift in the vertical direction, and the conductive edges 1' and 2' (thickness 0.09 mm) of the electrode plates 1 and 2 respectively protrude from the upper and lower end surfaces of the electrode body. ing. The figure shows that the conductive edge 1' of the anode plate 1 is led out from the upper end surface of the electrode body 4 , and the conductive edge 2' of the cathode plate 2 is led out from the lower end surface of the electrode body 4 .

Reference numeral 5 denotes an anode current collector which is electrically welded to the conductive edge 1' of the anode plate 1, and has a large number of openings 6.
It is made of a nickel-plated iron plate having an opening edge 7 having a thickness (0.12 mm) smaller than the thickness (0.20 mm) of the base material formed by performing secondary processing on this opening. 8 is a lead-out piece connected to the inner bottom surface of the anode cap 10, and 9 is an electrolyte injection hole. Reference numeral 5' denotes a cathode current collector which is electrically welded to the conductive edge 2' of the cathode plate 2, and is the same as the anode current collector except that there is no outlet or electrolyte injection hole.

This cathode current collector 5' is connected to the inner bottom surface of an exterior case 12 which also serves as a cathode terminal and is separated from the anode cap 10 by an insulating packing 11.

FIGS. 4 and 5 show an example of making a current collector according to the present invention. First, as shown in FIG. A preliminary opening is punched out using the first punching jig 21, and then this is punched out using the second punching jig 21 as shown in FIG.
is placed on the mold 30, and secondary processing is performed using a second punching jig 31 having a diameter larger than the preliminary opening to form an opening 6 and a thickness (0.12 mm) smaller than the thickness of the base material (0.20 mm). An opening flange 7 having a length approximately twice the thickness of the base material is formed.

According to the current collector of the present invention, it is possible to expect an improvement in high rate discharge characteristics by using a nickel plate or a nickel-plated steel plate with a thickness suitable for reducing the internal resistance of the battery. The edge dimensions are actively regulated to a predetermined value, and in particular, the thickness dimension is smaller than the thickness of the current collector base material and approximates the thickness of the conductive edge, which eliminates the above-mentioned problem caused by the difference in heat capacity during welding. The bonding force between the conductive edge and the current collector can be increased without any concern that this may occur.

When the size of the opening is made smaller than the thickness of the base material constituting the current collector, the projecting edges are formed by burrs generated during the formation of the opening, and the length and thickness of each projecting edge differs. For this reason, some of the thin projecting edges are fused during welding, and the state of welding with the conductive edge varies depending on the individual projecting edges, and the current density taken out from the electrode plate varies depending on the current collector used. become. In contrast, the current collector according to the present invention has an opening whose size is larger than the thickness of the base material constituting the current collector, and a projecting edge of a predetermined size is formed at the edge of the opening. It has a constant shape and size, the state of welding with the conductive edge is uniform on all the edges, and the current density taken out from the electrode plate does not vary greatly depending on the current collector used.

It is clear that the present invention can be applied not only to a spiral electrode body but also to a flat electrode body in which negative and anode plates are alternately stacked with separators interposed therebetween.

[Brief explanation of the drawing]

Figures 1 to 5 relate to the present invention; Figure 1 is a longitudinal sectional view of a storage battery using the current collector of the present invention;
The figure is a perspective view of the current collector of the present invention attached to the electrode body, Figure 3 is a perspective view of the current collector, Figures 4 and 5
The figure shows an example of the production of the current collector of the present invention, and FIGS. 6 and 7 show perspective views of conventional current collectors, respectively. 1... Anode plate, 1'... Conductive edge of the anode plate, 2
...Cathode plate, 2'...Conductive edge of cathode plate, 3...
Separator, 4 ... Electrode body, 5, 5'... Current collector, 6... Opening, 7... Projection.

Claims (1)

[Scope of utility model registration request] A current collector electrically welded to the conductive edges of predetermined electrode plates protruding from the upper and lower end surfaces of an electrode body consisting of positive and negative electrode plates and a separator inserted between these electrode plates, the current collector The body has a large number of openings whose dimensions are larger than the thickness of the base material constituting the current collector, and a projecting edge of a predetermined size is formed at the edge of the opening to form a welded portion with the conductive edge. 1. A current collector for a storage battery, wherein the thickness is smaller than the thickness of a base material constituting the current collector and approximates the thickness of the conductive edge.