JPS6054745B2 - lead acid battery - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a lead-acid battery, and more particularly to a lead-acid battery generally referred to as a stacked type.

A stacked lead-acid battery (hereinafter referred to as a storage battery) is made by laminating a plurality of bipolar plates with an anode active material layer formed on one side of a conductive partition wall and a cathode active material layer formed on the other side at an appropriate spacing. However, the stacked type is housed in a case along with an electrolyte.

As the above-mentioned storage battery, one using a conductive partition wall made of lead or a lead alloy is conventionally known. However, because the partition walls made of lead or lead alloy have a high specific gravity, the conventional storage batteries described above have the drawback of low output and capacity per unit weight. On the other hand, in Japanese Utility Model Publication No. 50-18096, a partition wall is made of a so-called conductive plastic, which is a resin such as an epoxy resin or a polyester resin mixed with a conductive substance such as powder or fiber of silver, lead, or carbon. A storage battery made of the following is described. Since the bulkhead of this conventional storage battery is essentially made of plastic, it has the advantage of higher output and capacity per unit weight than those using bulkheads made of lead or lead alloy as described above. On the other hand, simply mixing a conductive substance into a resin that does not originally have any conductivity does not result in a highly conductive plastic.
The electrical resistance of the partition walls, that is, the internal resistance of the storage battery, is large.
The drawbacks were energy loss and a large drop in terminal voltage when a large current was passed.

Furthermore, Japanese Utility Model Publication No. 50-42325 discloses that a plastic plate made of polystyrene, polyethylene, etc. is manufactured by penetrating several rods made of lead or lead alloy in the thickness direction of the plastic plate. describes a storage battery using partition walls that form local conductive paths in the thickness direction. However, this conventional storage battery has the drawback that the conductive path in the partition wall is extremely localized and its density is low, so the active material is not used effectively, resulting in low efficiency and ultimately low output and capacity per unit weight. It was hot. An object of the present invention is to solve the above-mentioned drawbacks of conventional storage batteries, and to provide a storage battery that has large output and capacity per unit weight, and has small energy loss and terminal voltage drop. To achieve the above object, the present invention provides a plastic sheet with
A cathode active material layer is formed on one side of the conductive partition wall, which penetrates the plastic sheet and is arranged to disperse a large number of conductive fibers so that the fiber axes are in the thickness direction of the plastic sheet, and a cathode active material layer is formed on the other side. It is characterized by a lead-acid battery that uses bipolar plates formed with material layers.

To explain the storage battery of the present invention based on the drawings, in the drawings, 3 is made of polytetrafluoroethylene resin, polyethylene resin, acrylic-styrene resin, epoxy resin, unsaturated polyester resin, etc., which has high oxidation resistance and chemical resistance. Thickness 1 made of thermoplastic or thermosetting resin? It is a plastic sheet.

In the thickness direction of the sheet 3, carbon fibers, lead fibers, silver fibers, nickel fibers, gold fibers, etc., which are oxidation-resistant and conductive, or non-conductive, penetrate through the sheet 3. Fibers made of glass fibers or the like that are made conductive by plating conductive metals such as gold, silver, platinum, etc., that is, conductive fibers 7, are dispersed so that their fiber axes are in the thickness direction of the sheet 3. As a whole, a partition wall 8 having conductivity in the thickness direction is formed. The conductive fiber 7 has a length equivalent to the thickness of the sheet 3, and maintains electrical contact between the end surface and the active material described below.
1 is a layer of an anode active material such as lead oxide formed on one surface of the partition wall 8, and 2 is a layer of a cathode active material such as lead formed on the other surface.

The thickness of the active material layers 1 and 2 is approximately 1 WI, and these active material layers 1 and 2 and the partition wall 8 constitute the bipolar plate 6. Reference numeral 5 denotes a case, in which a plurality of bipolar plates 6 are stacked at appropriate surface spacing, and an electrolyte (
Dilute sulfuric acid) 4 is added.

Although not shown, an injection hole for the electrolytic solution 4 and a gas vent hole are provided in the upper part of the case 5. In the storage battery as described above, charging and discharging are performed based on the following reactions.

That is, PbO2+Pb+2H2S0,=2PbS0
4+2H20 In the above, the conductive fiber has a utilization rate of active material. In order to increase the efficiency of the storage battery by increasing the efficiency of the storage battery, it is preferable that the particles be dispersed as uniformly as possible and as dense as possible when viewed from the direction perpendicular to the plane of the partition wall.

In addition, the volume ratio of the conductive fibers to the plastic sheet is usually 30 to 70 (%
) are selected within the range. In the above embodiment, the conductive fibers of the partition wall are configured such that both ends of the conductive fibers protrude slightly from the surface of the plastic sheet, and furthermore, the protruding portions are provided with other conductive fibers, such as lead fibers, or the surface is oxidized. Treated lead fibers or the like may be entangled.

This will ensure the retention of the active material and the electrical contact between the active material and the conductive fibers, further improving efficiency and ultimately increasing the output and capacity per unit weight of the storage battery. It becomes like this. Additionally, a glass fiber mat or other separator may be placed between the opposing surfaces of the bipolar plates.

The above-mentioned conductive partition walls can be made by arranging continuous conductive fibers in one direction and impregnating them with resin, then cutting them out in a direction perpendicular to the direction of the fibers after the resin has hardened, or cutting them out in a direction perpendicular to the direction of the fibers. They can be easily produced by soaking the surface of an object in an organic solvent, dissolving the resin on the surface, and making the tips of the conductive fibers protrude.

As explained above, in the storage battery of the present invention, the conductive partition walls of the bipolar plates are passed through the plastic sheet, and a large number of conductive fibers are formed so that the fiber axes thereof are in the thickness direction of the plastic sheet. Since it is constructed by dispersing the parts in this manner, the output and capacity per unit weight are large.

In addition, because the conductive fibers can be dispersed at high density and highly uniform, the electrical resistance of the partition walls, that is, the internal resistance, is low.
Therefore, there is little energy loss or drop in terminal voltage when a large current flows.

The fact that the conductive fibers can be dispersed at a higher density and more uniformly also means that the utilization rate of the active material is higher, and the efficiency of the storage battery is higher, resulting in a higher output per unit weight. Large capacity. Furthermore, when the conductive fibers are arranged so that their tips protrude from the surface of the plastic sheet, or when the protruding tips are entwined with other conductive fibers, it is difficult to retain the active material or to connect the active material. The contact with the conductive fibers is more reliable, the efficiency is further improved, and the output and capacity per unit weight of the storage battery is therefore further improved.

As mentioned above, the storage battery of the present invention has a large output and capacity per unit weight, and has low energy loss and small terminal voltage drop when a large current is passed, so it is suitable as a storage battery for automobiles, especially electric vehicles. Although it is suitable, the use is not particularly limited, and it is also useful as a storage battery for load leveling in power plants, ships, etc., for example.

[Brief explanation of the drawing]

The drawing is a schematic vertical cross-sectional view showing one embodiment of the storage battery of the present invention. 1... Anode active material layer, 2... Cathode active material layer, 3...
・Plastic sheet, 4... Electrolyte, 5... Case, 6... Bipolar plate, 7... Conductive fiber, 8...
Conductive bulkhead.

Claims (1)

[Claims] 1. Forming an anode active material layer on one surface of a conductive partition wall that penetrates the plastic sheet and has a large number of conductive fibers dispersed so that the fiber axes thereof are in the thickness direction of the plastic sheet, A lead-acid battery that uses bipolar plates with a cathode active material layer formed on the other side.