JP3036245B2 - Cathode plate for lead-acid battery and thin sealed lead-acid battery - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thin sealed lead-acid battery and a cathode plate for the lead-acid battery suitable for use in the battery.

[0002]

2. Description of the Related Art A typical example of a thin sealed lead-acid battery is a so-called film-pack type sealed lead-acid battery. This type of battery is superior in that the battery case can be made thinner and a thinner and lighter lead-acid battery can be provided, as compared with a small sealed lead-acid battery using a monoblock battery case known before. Typically, an electrode group consisting of one anode plate, one retainer, and one cathode plate is housed in a battery case made of a film-shaped or sheet-shaped synthetic resin body. However, in order to increase the capacity of this type of battery, it is necessary to adopt a configuration in which the cathode plate is a paste-type electrode plate and two cathode plates are arranged on both sides of the anode plate. Become.

[0003]

The paste-type cathode plate which is widely used at present is prepared by applying a cathode paste to a current collector such as a casting grid, an expanded grid, a punched grid, etc., aging, drying, and then electrolyzing. A cathode plate provided with an active material layer is obtained by reduction. However, as long as the current collector supports the active material layer like a conventional cathode plate, the thickness of the cathode plate cannot be made thinner than about 1 mm. This is a major obstacle to thinning storage batteries. Further, the conventional thin sealed lead-acid battery using the cathode plate has a problem that it is difficult to improve the weight energy density.

An object of the present invention is to provide a cathode plate for a sealed lead-acid battery which is thin and can achieve high energy density.

Another object of the present invention is to reduce the thickness of a storage battery even when using an electrode group in which two cathode plates are arranged on both sides of the anode plate in order to increase the utilization rate of the anode plate. It is another object of the present invention to provide a thin sealed lead-acid battery that can achieve high energy density.

[0006]

According to the first aspect of the present invention, a lead plate for a lead-acid battery is provided with a retainer having a paste filling recess and an active material formed by filling the paste filling recess with an active material paste. It comprises a material layer and a current collector made of a lead or lead alloy foil bonded to the active material layer.

According to a second aspect of the present invention, an electrode group in which two cathode plates are arranged on both sides of an anode plate using the cathode plate according to the first aspect of the present invention is formed. A lead-acid battery is constructed.

[0008]

In the cathode plate used in the first and second aspects of the present invention, a thin lead or lead alloy foil is used as a current collector because a retainer having a paste filling recess serves as a support for the active material layer. Can be used, and it is possible to reduce the thickness and weight, and it is possible to greatly increase the weight energy density. Further, in the case where the active material paste is filled in the paste filling concave portion to form the active material layer, the amount of the active material paste to be filled can be increased, so that the capacity can be increased.

[0009]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1A is a partially cutaway perspective view showing the configuration of an embodiment of the cathode plate of the present invention, and FIG.
It is a BB sectional view taken on the line of (A). In these figures,
1 is a retainer provided with a paste filling recess 1a,
Reference numeral 2 denotes an active material layer, and reference numeral 3 denotes a current collector made of a lead or lead alloy foil. The retainer 1 is formed of a glass nonwoven fabric or the like in the same manner as in the related art, and in the illustrated example, by forming an annular dam portion 1b protruding on one side (front surface) side, the paste filling recess 1a is formed. It is formed. An annular groove 1c formed on the other side surface (rear surface) of the retainer 1 so as to face the dam portion 1b is formed by an annular convex portion formed around a metal mesh used for papermaking the retainer 1. It is a thing. When performing papermaking of the retainer using a metal mesh for papermaking having an annular convex portion,
Retainer material fibers such as glass fibers are deposited on the annular convex portion in a state of being raised more than other portions. After the paper making, drying is performed together with the metal mesh, and the retainer is peeled off from the metal mesh after the drying, so that a retainer having the recess 1a for paste filling can be obtained as shown in the figure. Incidentally, the thickness D1 of the base portion of the retainer 1 produced in the test was about 0.8 mm, and the height D2 of the weir portion 1b was about 0.6 mm.

As the active material paste to be filled in the paste filling recess 1a of the retainer 1, a paste having a viscosity lower than that of a paste used when manufacturing a normal paste type cathode plate is used. This is for improving the filling property of the paste. Even if the viscosity is lowered, the viscosity is not so low that the filled paste easily leaks from the porous portion of the retainer. Before drying the active material paste,
A current collector 3 made of lead or a lead alloy foil is pressed onto the undried active material paste layer, and then the conventional aging,
Drying was performed to obtain the desired cathode plate with integral retainer. The current collector used for the test was a punched lead foil having a thickness of 80 μm. The cathode plate for a test thus manufactured had a thickness of the retainer of about 0.8 mm and a thickness of the cathode portion including the active material layer 2 and the current collector 3 of about 0.65 mm.

FIG. 2 is a schematic sectional view of an embodiment of the thin sealed lead-acid battery of the present invention using the cathode plate shown in FIG.
In this storage battery, the cathode plate shown in FIG. 1 is stacked on both sides of a conventionally used paste type anode plate 4 having a thickness of about 1.0 mm with the retainers 1 and 1 facing the anode plate 4 side. The plate group 5 is constituted. In the present embodiment, in order to protect the electrode group, the electrode group is wrapped in a shrink film that shrinks when heat or the like is applied, and the film is shrunk to pack the electrode group. The pack applies a pressing force to the electrode plate group in the thickness direction. FIG. 2 schematically shows the cathode terminal 6 and the anode terminal 7. The cathode terminal 6 may be connected to the current collectors 3 by a conductive adhesive, spot welding, or the like. The cathode terminal 6 is provided when punching a lead or lead alloy foil constituting the current collector 3. Alternatively, the current collector 3 having the cathode terminal 6 integrated therewith may be formed by punching out the shape. Reference numeral 8 denotes a terminal holder made of synthetic resin which can be welded by heat. The holder 8 to which the cathode terminal 6 and the anode terminal 7 are fixed and the electrode plate group 5 are wrapped with two film-like or sheet-like synthetic resin bodies 9 and 10,
The surroundings of the synthetic resin bodies 9 and 10 were heat-welded to form the battery case 11. In FIG. 2, the thickness of the synthetic resin bodies 9 and 10 is not shown. The total thickness of the storage battery prepared under the same conditions as the conventional one in both the structure and the manufacturing method except for the above-described retainer-integrated cathode plate was 4.1 mm. A similar storage battery was also prepared with the same 4.1 mm anode plate and one cathode plate via a retainer, and a capacity test was performed to calculate the weight energy density. Thirteen storage batteries were used for the test, and a 5-hour discharge test was performed. The weight energy density of the storage battery of the present invention was 49.2 wh / kg, while that of the conventional storage battery was 32.4 wh / kg. The storage battery of the present invention has a weight energy density that is about 1.5 times that of the conventional storage battery.

The utilization rate of the anode plate of the battery of the present invention is about 50.
%, Which is one conventional anode plate and one cathode plate.
This is a value that cannot be realized with a single anode plate utilization rate. In the sealed lead-acid battery of this embodiment, by integrating the retainer and the cathode plate, one anode plate and two cathode plates in a thin sealed lead-acid battery having a thickness of about 4 mm, which could not be produced conventionally, were obtained. Can be realized very easily. As a result, the weight energy density can be improved about 1.5 times as compared with the conventional battery. Further, when the cathode plate of the present invention is used, since the retainer and the cathode plate are integrated, even if the thickness of the electrode plate is reduced, the handling is easy and the production time can be shortened. Further, since the retainer is provided with a weir, the weir prevents the short circuit with the anode plate. As described above, the present invention has great industrial value in that a thin high-energy-density sealed lead-acid battery can be easily realized.

[0013]

According to the present invention, a thinner lead or lead alloy foil can be used as a current collector because the retainer having the paste filling recess serves as a support for the active material layer. This has the advantage that the thickness and weight of the battery can be reduced and the weight energy density of the sealed lead-acid battery can be greatly increased.

[Brief description of the drawings]

FIG. 1A is a partially cutaway perspective view illustrating a configuration of an embodiment of a cathode plate according to the present invention, and FIG.
It is a BB sectional view taken on the line of (A).

FIG. 2 is a schematic vertical sectional view of the thin sealed lead-acid battery of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Retainer 2 Active material layer 3 Current collector 4 Anode plate 5 Electrode group 6 Cathode terminal 7 Anode terminal 8 Terminal holder 9, 10 Film-shaped or sheet-shaped synthetic resin body 11 Battery case

Continuation of the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) H01M 4/14 H01M 10/12 H01M 2/18

Claims (2)

(57) [Claims] 1. A retainer having a paste filling recess,
A lead-acid battery comprising: an active material layer formed by filling an active material paste in the paste filling recess; and a current collector made of a lead or lead alloy foil bonded on the active material layer. Cathode plate. 2. A thin hermetically sealed type in which an electrode group formed by superposing two cathode plates so as to sandwich an anode plate therebetween is housed in a battery case made of a film or sheet synthetic resin body. In the lead-acid battery, the two cathode plates include a retainer having a paste filling recess, an active material layer formed by filling the paste filling recess with an active material paste, and an active material layer formed on the active material layer. And a current collector made of bonded lead or lead alloy foil. The electrode plate group is formed by stacking the two cathode plates so as to contact the retainer with the anode plate. Type sealed lead storage battery.