Matsushita Electric Industrial Co., Ltd.

Go Kashio

Yasuyuki Yoshihara

Kazuyoshi Yonezu

Fumiaki Seta

Akira Iwamura

An electrode includes an expanded grid and an active material provided on the grid, the thickness of the grid is the same as the strand and connecting sections of the strand, presenting a waveform as a whole. When this grid is used in the electrode as a current collector, the connecting sections are located near the center of the thickness direction of the electrode and strand are arranged by projecting upward and downward, respectively, from the boundary where the connecting sections are situated. Accordingly, a lead-acid storage battery having long life characteristics is made available.

Storage battery

A lead-acid storage battery uses as a current collector an expanded grid produced by processing a belt shaped material formed of lead or lead alloys. Strand of a grid for negative electrodes have a twist. The extent of the negative electrode's grid is larger than that of the positive electrode's grid. Accordingly, degradation of output characteristics in the domain deep in the depth of discharge is prevented and further high rate discharge cycle life characteristics are improved.

A manufacturing method for an expanded grid includes the steps of: (a) supplying a thin plate of band form from the longitudinal direction, (b) forming a plurality of intermittent cuts parallel to the edge in a first region, excluding the central portion, of the thin plate of band form, (c) bending the central portion at a desired angle, and (d) expanding and developing the cuts in the width direction, while moving sequentially in the longitudinal direction the thin plate having the first region forming the plurality of cuts and the central portion not having the cuts, in which the first track distance of the outermost side portion of the first region having the cuts developed and formed is nearly the same distance as the track distance of the central portion. The plane distortion of the grid is eliminated, the width dimension of the grid is stable, and the quality of the electrode plate using such grid is enhanced. Further, local stress concentration of the grid is suppressed.

Manufacturing method of expanded grid and its manufacturing apparatus

A slit is formed in a clad sheet integrating a thin layer of lead alloy containing at least one of tin and antimony at least on one side ot a parent material made of lead or lead-calcium system alloy. The clad sheet is processed by expanding to twist the rib of the formed grid, and the thin layer of the lead alloy containing at least one of tin and antimony is spirally oriented in multiple directions, as the positive electrode plate. An expanded grid is thus formed. In this manner charging reception characteristics after long-term storage following deep discharge at high temperature ot a lead-acid battery are improved.

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Aichi, Japan

Go Kashio