Alkaline storage battery with scroll electrode body

Abstract

An alkaline storage battery including a group of spiral electrodes composed of positive and negative electrode plates spirally wound with a separator interposed therebetween and contained in a metallic cell casing used as an external terminal wherein the group of spiral electrodes is formed at its central portion with a space defined by a winding core during the winding process of the electrode plates and is provided with a first current-collector welded to an upper end of one of the electrode plates and a second current-collector welded to a lower end of the other electrode plate, wherein the second current-collector is welded to an internal surface of the bottom of the cell casing without being welded to an end portion of the other plate located at the outermost periphery of the group of spiral electrodes, and wherein the other electrode plate at the outermost periphery of the group of spiral electrodes is pressed into contact with an internal peripheral wall of the cell casing.

Description

technical field [0001] The present invention relates to an alkaline storage battery with a scroll-shaped electrode body in which a separator is interposed between the positive and negative plates of a nickel-metal hydride storage battery, a nickel-cadmium storage battery, etc., and is particularly related to a scroll-shaped electrode body and The conductive connection between the current collectors and the conductive connection between the scroll-shaped electrode body and the metal outer can. Background technique [0002] Alkaline accumulators such as existing nickel-metal hydride accumulators, nickel-cadmium accumulators have, after intervening separator between positive and negative pole plate and being wound into the scroll-shaped electrode group of spiral shape, the positive plate of this scroll-shaped electrode group Weld the current collector for the positive electrode on the upper end of the spiral electrode group, weld the current collector for the negative electrode...

AI Technical Summary

Problems solved by technology

[0005] However, if the current collector for the negative electrode is made so large that it does not come into contact with the metal outer can, there will be a part where the current collector for the negative electrode is not welded on the welded part of the negative electrode plate and the current collector for the negative electrode.

If there is a part where the current collector for the negative electrode is not welded, the current distribution of the current collection path from the current collector for the negative electrode to the negative plate will become uneven, and a voltage drop will occur at the part where the current collector for the negative electrode is not welded

Although such a voltage drop does not become a big problem in the case of charging and discharging with a small current, in the case of charging and discharging with a large current of tens of amperes to hundreds of amperes, a large voltage drop is caused by the resistance of the above-mentioned connection part and thus Reduce the operating voltage, resulting in the problem of not being able to obtain a high voltage, resulting in the problem of reducing the high-rate discharge characteristics

In addition, since the reaction heat (endothermic reaction) of the nickel-metal hydride storage battery is smaller than that of the nickel-cadmium storage battery, the problem of increasing the temperature rise due to the influence of Joule heat and increasing the internal pressure during charging occurs.

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