Japan Storage Battery Co., Ltd.

Masahiko Kosai

Takao Omae

Akira Kamada

Akio Tokunaga

Toshiaki Hayashi

Teruhiro Hatanaka

Kenji Yamanaka

Shigeharu Osumi

Graphite powder having a mean particle size not larger than 30 &mgr;m is added to a negative electrode plate for a lead storage battery. Preferably, the amount of graphite powder added is in the range of from 0.3% to 2% by weight. Preferably, vein powder is used as the graphite powder. More preferably, 0.3% or more by weight of an organic expander is added.

Negative electrode plate for lead storage battery

A method for producing a grid for a lead storage battery has a first step, a second step and a cooling step performed between the first and second step. In the first step, lead alloy is sequentially rolled over a plurality of rolls. In the second step, the rolled sheet obtained at the first step is machined to produce a grid for a lead storage battery. In the cooling step, the rolled sheet is cooled so that (1) the surface temperature thereof is 10&deg; C. or lower at least once and (2) the total time during which the rolled sheet is exposed to an atmosphere of higher than 10&deg; C. is 10 hours or less.

Method for producing grid for a lead storage battery

A valve-regulated lead-acid battery produced by a so-called container formation method including preparing a battery from unformed positive and negative plates filling a predetermined dilute sulfuric acid into said battery, and then applying an electric current to said battery so that the group of plates is formed by container formation is provided. The valve-regulated lead-acid battery has an negative active material containing an oil incorporated therein. The amount of the oil to be incorporated is from 0.05 to 1% by weight. The oil may be a paraffinic oil, naphthenic oil, olefinic oil, aromatic oil or silicon-based oil.

Valve-regulated lead-acid battery

A sealed lead-acid battery which includes a container accommodating an assembled element. The assembled element has at least one electrochemically formed positive plate having a grid of an antimony-free alloy, wherein the plate is made of porous active material. The assembled element also includes at least one electrochemically formed negative plate having a grid of an antimony-free lead alloy, wherein the plate is made of a porous active material. A separator, having a plurality of projections on one or both side thereof, is inserted between the positive and negative plates. A layer of powder is placed between the positive and negative plates and around the assembled element. The powder is composed of a closely packed powder, which is acid-resistant and hydrophilic, and has gas channels within its interior. The powder is immobilized with an acid-resistant porous layer placed above the powder, wherein the porous layer is permeable to gases and liquids, and impervious to particles of the powder. Sulfuric acid electrolyte is impregnated and retained within the positive and negative plates and the powder layer in a substantially necessary and sufficient amount for charging and discharging the battery.

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Kyoto, Japan

Masahiko Kosai