JPH07183028A - Expanded metal plate and its manufacture - Google Patents

Abstract

PURPOSE:To reduce variations in the height of an expanded metal plate by indenting the surface of the active material of the expanded metal plate. CONSTITUTION:Each of expanded metal plates 2 forming an expanded metal grating 1 is filled with an active material 6. The active material 6 is indented 7 so as to have thinner portions 9 at regular intervals, where contraction stresses concentrate when the paste of the active material is dried. Cracks that form when the paste of the active material is dried also occur in the portions 9, absorbing the contraction stresses of the plates 2. Therefore, the amount by which the expanded metal plate 1 contracts along its height is reduced, and variations in the height dimension of the expanded metal plate 1 are reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an expanded electrode plate having a structure in which an expanded grid is filled with an active material, and a method for producing the expanded electrode plate.

[0002]

2. Description of the Related Art Conventionally, a grid of a lead-acid battery for an automobile has been manufactured by a book mold type casting method. The percentage is increasing.

This expanded lattice is lighter in weight than the cast lattices used so far, and has the characteristic of being extremely high in productivity.

[0004]

However, the expanded lattice has a problem that its mechanical strength is lower than that of the cast lattice. In particular, it is vulnerable to tension and compression in the expanding direction, and when the filled active material paste is dried to manufacture an expanded electrode plate, there is a problem that the expansion grid deforms and contracts due to the contraction.

Since this shrinkage amount changes due to a slight change in the water content of the active material paste, the amount from the lower part of the expanded electrode plate 2 using the expanded grid 1 to the current collector ear 3 as shown in FIG. There is a problem that the height A becomes unstable.

Therefore, when the electrode plate group welded portion 5 is formed when the electrode plate group 4 is formed by stacking the expanded electrode plates 2 in the battery assembly process following the expanded electrode plate formation process as shown in FIG. As shown in FIG. 11, the insertion amount of the current collector ears 3 inserted into the electrode plate group welded portions 5 is different for each expanded electrode plate 2, and the electrode plate group welded portions 5 and the current collector ears 3 are different. Since the welding conditions of No. 1 are non-uniform for each expanded electrode plate 2, a gap 5a is generated at the interface between the electrode plate group welded portion 5 and the current collector ear portion 3, and the electrode plate group welded portion 5 is defective. There was a problem that led to the occurrence and the decrease in reliability.

An object of the present invention is to provide an expanded electrode plate and a method for manufacturing the same which can reduce the amount of contraction of the expanded electrode plate in the height direction and reduce the variation in height of the expanded electrode plate. .

[0008]

The means of the present invention for achieving the above object will be described below.

According to a first aspect of the present invention, in an expanded electrode plate having a structure in which an active material is filled in an expanding grid, recesses are provided at regular intervals on the surface of the active material in the expanding direction of the expanding grid. Is characterized by.

According to a second aspect of the present invention, there is provided an expanding electrode plate manufacturing method for manufacturing an expanding electrode plate having a structure in which an active material is filled in an expanding grid, wherein a roller having convex portions on its surface at predetermined intervals is used, The undried expanded electrode plate in which the active grid paste is filled in the expanded grid is passed through the roller, and recesses are provided at predetermined intervals on the surface of the active material paste.

[0011]

When the recesses are provided at regular intervals on the surface of the active material in the expanding direction of the expanding electrode plate as in claim 1,
In the cross section of the active material in the expanding direction of the expanded electrode plate, there are thin portions at regular intervals. When the expanded electrode plate is provided with a thin portion in this manner, the contraction stress generated when the active material paste is dried is concentrated, and the crack generation caused when the active material paste is dried is caused in this part. , Absorbs the contraction stress of the expanded electrode plate, reduces the amount of contraction of the expanded electrode plate in the height direction, and reduces the variation in height of the expanded electrode plate.

When the variation in height of the expanded electrode plate is reduced in this way, the amount of insertion of the current collector ears inserted in the electrode plate group welded portion becomes constant for each expanded electrode plate, so that The flux application amount and heat capacity are also constant, the welding conditions of the electrode plate group welded portion and the current collector ear portion are made uniform in each expanded electrode plate, and the electrode plate group welded portion and the current collector ear portion are The gaps generated at the interface of the electrode plate group are reduced, the defects of the electrode plate group welded portion can be reduced, and the reliability can be improved.

According to a second aspect of the present invention, a roller having convex portions on its surface at predetermined intervals is used, and an undried expanded electrode plate having an expanded grid filled with an active material paste is passed through the roller. It is possible to easily form recesses at predetermined intervals on the surface of the active material paste.

[0014]

1 to 3 show one embodiment of the expanded electrode plate according to the present invention. The expanded electrode plate 2 of this embodiment has a structure in which cross-shaped recesses 7 are provided at regular intervals on both surfaces of the active material 6 filled in the expanded grid 1. The locations where such recesses 7 are provided are preferably locations corresponding to the windows 8 of the expanding lattice 1.

As described above, when the recesses 7 are provided on both surfaces of the active material 6 in the expanding direction of the expanding electrode plate 2 at regular intervals, the cross section of the active material 6 in the expanding direction of the expanding electrode plate 2 is shown in FIG. As shown, the thin portions 9 are present at regular intervals. When the expanded electrode plate 2 is provided with the thin portion 9 as described above, shrinkage stress generated when the active material paste dries is concentrated on the thin portion 9 and when the active material paste dries. As shown in FIGS. 4 and 5, the generation of cracks 10 is caused in the thin portion 9 to absorb the contraction stress of the expanded electrode plate 2 and to contract the expanded electrode plate 2 in the height direction. The amount is reduced, and the variation in height of the expanded electrode plate 2 is reduced.

When the variation in height of the expanded electrode plates 2 is reduced in this way, as shown in FIG. 6, the insertion amount of the current collector ears 3 to be inserted into the electrode plate group welded portions 5 depends on each expanded electrode plate 2. Since it becomes constant every time, the flux application amount and heat capacity of this portion also become constant, the welding conditions of the electrode plate group welded portion 5 and the current collector ear portion 3 are made uniform in each expanded electrode plate 2, and The gap generated at the interface between the electrode plate group welded portion 5 and the current collector ear portion 3 was eliminated, defects in the electrode plate group welded portion 5 were reduced, and reliability could be improved.

When the heights of the expanded electrode plate 2 of the present invention and the conventional expanded electrode plate 2 after drying were compared, the following results were obtained. The conventional expanded electrode plate 2 contracted by α after drying, and the height of the expanded electrode plate 2 was (A-α) as shown in FIG. 9. On the other hand, the expanded electrode plate 2 according to the present invention contracted by β after drying, and the height of the expanded electrode plate 2 became (A-β) as shown in FIG. Cracks 1 on the thin portion 9 formed on the plate 2
Since it was absorbed by generating 0, the amount of shrinkage became smaller than in the conventional case (β <α), and the variation in height of the expanded electrode plate 2 became small as shown in Table 1.

[0018]

[Table 1] FIG. 7 shows an example of a method for manufacturing the expanded electrode plate 2 of the present invention described above. In this embodiment, a pair of rollers 12 having cruciform convex portions 11 on the surface at equal intervals are used, and an undried expanding electrode plate 2 in which the expanding grid 1 is filled with the active material paste 6a is used. Passing between the rollers 12, cross-shaped recesses 7 are provided at regular intervals on both surfaces of the active material paste 6a. After that, when the expanded electrode plate 2 is dried, as shown in FIG. 4 and FIG.
Cracks 10 in the thin portion 9 of the expanded electrode plate 2
Occurs.

The shape of the recess 7 is not limited to the cross shape, but may be an appropriate shape such as a diamond shape.

The recess 7 may be provided only on the surface of one side of the expanded electrode plate 2.

[0021]

As described above, according to the expanded electrode plate and the manufacturing method thereof according to the present invention, the following excellent effects can be obtained.

In the expanded electrode plate according to claim 1,
Since the recesses are provided at regular intervals on the active material surface in the expanding direction of the expanding electrode plate, in the active material cross section in the expanding direction of the expanding electrode plate, there will be thin portions at constant intervals. Shrinkage stress concentrates in the thin part in the drying process, and cracks that occur when the active material paste dries occur in this thin part, and the shrinkage stress of the expanded electrode plate is absorbed in this part. It is possible to reduce the amount of contraction of the expanded electrode plate in the height direction and reduce the variation in height of the expanded electrode plate.

When the variation in height of the expanded electrode plate is reduced in this way, the amount of insertion of the current collector ears inserted in the electrode plate group welded portion becomes constant for each expanded electrode plate, so that The amount of flux applied and the heat capacity are also constant, the welding conditions of the electrode plate group welded portion and the current collector ear portion are made uniform in each expanded electrode plate, and the electrode plate group welded portion and the current collector ear portion are The gaps generated at the interface of the electrode plate group are reduced, the defects of the electrode plate group welded portion can be reduced, and the reliability can be improved.

In the method for producing an expanded electrode plate according to claim 2, a roller having convex portions on its surface at predetermined intervals is used, and an undried expanded electrode plate in which an expanding grid is filled with an active material paste is provided on the roller. Since it is passed, the recesses can be easily provided at predetermined intervals on the surface of the active material paste of the expanded electrode plate.

Further, when the undried expanded electrode plate is passed through the roller, the close contact state between the active material paste and the expanded grid can be improved.

[Brief description of drawings]

FIG. 1 is a front view showing a state after drying of an embodiment of an expanded electrode plate according to the present invention in which an active material is omitted and displayed.

FIG. 2 is a perspective view of an essential part of the expanded electrode plate of the present embodiment in a non-dried state.

3 is a cross-sectional view taken along line XX of FIG.

FIG. 4 is a perspective view of an essential part of the expanded electrode plate of this embodiment after being dried.

5 is a cross-sectional view taken along the line YY of FIG.

FIG. 6 is a vertical cross-sectional view showing an example of an electrode plate group welded portion of an electrode plate group using the expanded electrode plate according to the present invention.

FIG. 7 is a perspective view showing an embodiment of a method for manufacturing an expanded electrode plate according to the present invention.

FIG. 8 is a front view of a conventional expanded electrode plate in which an active material in a non-dried state is omitted.

FIG. 9 is a front view of a conventional expanded electrode plate in which a dry active material is omitted.

FIG. 10 is a perspective view of an electrode plate group using a conventional expanded electrode plate.

FIG. 11 is a cross-sectional view of an electrode plate group welded portion of an electrode plate group using a conventional expanded electrode plate.

[Explanation of symbols]

 1 Expanded Lattice 2 Expanded Electrode Plate 3 Current Collector Ear Part 4 Electrode Plate Group 5 Electrode Plate Group Welded Part 5a Gap 6 Active Material 6a Active Material Paste 7 Recess 8 Window 9 Thin Part 10 Crack 11 Convex 12 Roller

Claims (2)

[Claims] 1. An expanded electrode plate having a structure in which an active material is filled in an expanded grid, wherein recesses are provided at regular intervals on the surface of the active material in the expanding direction of the expanded grid. . 2. A method for manufacturing an expanded electrode plate having a structure in which an expanded grid is filled with an active material, wherein a roller having convex portions on its surface at predetermined intervals is used, and the expanded grid is coated with the active material paste. A method for producing an expanded electrode plate, characterized in that the undried expanded electrode plate filled with is passed through the roller to form recesses at predetermined intervals on the surface of the active material paste.