JP2002334701A - Lattice for lead-acid battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lead-acid battery having excellent service life performance. SOLUTION: This lattice for lead-acid batteries is characterized by having a first layer 51 made of a lead alloy, a second layer 52 made of a lead alloy and disposed on one side of the first layer, and a third layer 53 made of lead or a lead alloy and disposed between the first and second layers, the third layer being softer than the first and second layers. For example, a lead-calcium alloy can be mentioned as the first layer, a calcium-rich lead-calcium alloy as the second layer, and pure lead or a lead-tin alloy as the third layer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a grid for a lead-acid battery.

[0002]

2. Description of the Related Art Ex-band gratings and punched gratings are manufactured by subjecting sheet-like lead or lead alloy to an ex-band or punching process. These grids have the advantage of being able to be produced continuously, although they have lower mechanical strength than cast grids. In addition, since the stage before taking the shape of the lattice is sheet-like, it is relatively easy to attach a lead alloy of another composition to the surface of the sheet by pressure welding. On the other hand, the casting grid has no other method than plating to attach a lead alloy of another composition to its surface.

As described above, by attaching a lead alloy having a different composition as the second layer to the surface of the lattice as the first layer, the electrochemical characteristics and mechanical strength inherent to the lattice itself are obtained. The reaction at the interface between the lattice and the active material can be improved while maintaining the same. For example, a lead-calcium-based alloy lattice that does not include a composition that reduces the hydrogen overvoltage is often used in a sealed lead-acid battery. The interface is selectively discharged, and a dense lead sulfate layer may be generated at the interface between the lattice and the active material. When this layer is formed, the electrochemical contact between the lattice and the active material is cut off because of the insulating layer, and the active material cannot be discharged any more.
However, it is known that when a lead-antimony-based alloy, a lead-tin-based alloy, or the like is attached to at least a part of the surface of the lattice, the phenomenon caused by the selective discharge at the interface as described above is suppressed. (JP-A-63-2111567).

[0004]

However, in order to attach the second layer having a different composition to the lead-acid battery grid corresponding to the first layer, it is difficult to perform the plating method continuously using a cast grid. It is not practical because there is only. Therefore,
In order to attach the second layer having a different composition to the lead-acid battery grid corresponding to the first layer, in a part of the manufacturing process,
Expanded or punched grids that take the form of a sheet are suitable. This is because the process of manufacturing the sheet has a thickness c
This is because a continuous cast plate having a thickness of from m to several tens cm is rolled into a sheet having a predetermined thickness. On the surface of this continuous cast plate,
By rolling a continuous cast plate after placing a lead alloy foil having a different composition from that of the continuous cast plate, the alloy foil can be relatively easily integrated with the continuous cast plate to form a sheet.
However, the second layer having a different composition from that of the continuous cast plate is lead-free.
A relatively soft material such as an antimony-based alloy or a lead-tin-based alloy is relatively easy to install, whereas a lead-calcium alloy containing a high concentration of calcium is a lead-antimony-based alloy or the like. Since it is harder than a lead-tin-based alloy or the like, it has a problem in that it cannot be pressed well with the sheet as the first layer in the rolling step, and is easily peeled off.

[0005] The present invention relates to a lead alloy corresponding to the first layer,
An object of the present invention is to provide a grid in which the second layer, which is hard and difficult to mount in the conventional technology, is securely mounted, surface modification of the grid is ensured, and a lead storage battery including the grid.

[0006]

According to a first aspect of the present invention, there is provided a first layer comprising a lead alloy and a second layer comprising a lead alloy disposed on one surface of the first layer. And a third layer of lead or a lead alloy disposed between the first layer and the second layer, the third layer being more than the first and second layers. This is a lead-acid battery grid characterized by being soft.

A second invention is the grid for a lead-acid battery according to claim 1, wherein the second layer and the third layer are arranged only on one surface of the first layer.

A third invention is the grid for a lead-acid battery according to claim 1, wherein the second layer and the third layer are arranged on both surfaces of the first layer.

According to a fourth aspect of the present invention, there is provided the grid for a lead-acid battery according to any one of claims 1, 2 and 3, wherein the third layer is made of pure lead or a lead-tin alloy.

A fifth aspect of the present invention is characterized in that the first layer is made of a lead-calcium alloy and the second layer is made of a lead-calcium alloy having a higher calcium content than the first layer. A grid for a lead storage battery according to claim 4.

In a sixth aspect of the present invention, the second layer and the third layer are integrated by pressure welding.
6. The grid for a lead storage battery according to 2, 3, 4 or 5.

According to a seventh aspect of the present invention, there is provided a grid for a lead storage battery according to any one of claims 1, 2, 3, 4, 5 and 6, wherein the grid is manufactured by an expanding method or a punching method.

According to an eighth aspect of the present invention, there is provided an electronic device comprising:
A lead-acid battery using the lead-acid battery grid described in 4, 5, 6, or 7.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The first layer according to the present invention includes:
As the charge and discharge are repeated, the interface between the grid and the active material is gradually discharged selectively, and a dense lead sulfate layer is generated at the interface between the grid and the active material. Lead-calcium-based alloys, in which the electrochemical contact is cut off and the discharge capacity may be extremely reduced even if there is no abnormality in the active material, can be mainly used.

Further, as the second layer according to the present invention, a lead-calcium alloy which is difficult to attach to the first layer, is hard, has poor ductility and malleability, and has a calcium concentration of about 1 wt% is suitable.

Further, as the third layer according to the present invention,
As described in the claims, pure lead or a lead-tin alloy, which is softer than the first and second layers, is suitable.

The above-mentioned first to third layers are merely examples, and it is optional to change the composition of the layers according to the manufacturer's purpose.

As a method of manufacturing the lattice according to the present invention, various methods typified by rolling, plating, vapor deposition, and sputtering can be considered. Rolling is most suitable in consideration of manufacturing cost and productivity.

When manufactured by rolling, when the second and third layers are attached to one surface of the first layer, the cross section of the lattice has a three-layer structure, and the second and third layers are provided on both surfaces of the first layer. When three layers are attached, the cross section of the lattice has a five-layer structure.

The rolled sheet produced by rolling becomes a lattice by expanding or punching.

Note that the definition of softness described herein is softness determined by a Vickers hardness measurement method.

[0022]

(Embodiment 1) As shown in FIG.
Thickness 10c of 07wt% Ca-1.0wt% Sn alloy
m of a continuous cast plate (Vickers hardness 1)
6) On one surface of 11, a 0.5 mm thick pure lead foil (Vickers hardness 5) 13 as a third layer and a 0.3 mm thick Pb-1.0 wt% Ca foil (Vickers hardness) as a second layer 23) Each of 12 was led to a rolling mill having eight rolling rolls 21. Thus, a three-layer rolled sheet 31 having a thickness of 1 mm was manufactured. At this time, pure lead foil 13 as the third layer and Pb-1.0 wt% as the second layer were used.
The Ca foil 12 was used in a sheet form and was continuously supplied to a continuous cast plate. At this time, the third layer and the second layer
Are theoretically 5 μm and 3 μm, respectively.

The three-layer rolled sheet 31 was guided to an expander 22 and expanded. The expanded rolled sheet 32 has lead powder and 3
After filling a paste obtained by kneading wt% of red lead and a predetermined amount of dilute sulfuric acid, an expanded positive electrode plate cut into a predetermined shape was manufactured.

On the other hand, Pb-0.07 wt% Ca-1.0
A 10% thick continuous cast plate of a wt% Sn alloy was guided to a rolling mill having eight rolling rolls to produce a rolled sheet having a thickness of 1 mm. The three-layer rolled sheet is guided to an expander and expanded, and the expanded rolled sheet is mixed with lead powder, ligninsulfonic acid, barium sulfate, carbon, and a predetermined amount of dilute sulfuric acid. After filling the kneaded paste, an expanded negative electrode plate cut into a predetermined shape was manufactured.

The five positive electrode plates and six negative electrode plates thus manufactured are alternately laminated via a glass fiber separator to form an electrode group. After inserting the electrode group into a battery case, A predetermined amount of diluted sulfuric acid electrolyte was injected to produce a conventional sealed lead-acid battery (X) of 2V10Ah.

Here, for comparison, as shown in FIG. 2, a 10 cm thick continuous cast plate of Pb-0.07 wt% Ca-1.0 wt% Sn alloy (Vickers hardness 16)
On one side of No. 11, a 0.3 mm thick Pb-
A 1.0 wt% Ca foil (Vickers hardness 23) 12 was placed thereon, and led to a rolling mill having eight rolling rolls 21. Thus, a two-layer rolled sheet 41 having a thickness of 1 mm was manufactured. At this time, Pb-1.0 wt% C as the second layer
The a foil 12 was a sheet-like material and was continuously supplied to a continuous cast plate. At this time, the thickness of each of the second layers is theoretically 3 μm.

The two-layer rolled sheet 41 was guided to an expander 22 and expanded. The expanded rolled sheet 42 has lead powder and 3
After filling a paste obtained by kneading wt% of red lead and a predetermined amount of dilute sulfuric acid, an expanded positive electrode plate cut into a predetermined shape was manufactured.

The five positive electrode plates manufactured in this way and the six negative electrode plates described above are alternately laminated via a glass fiber separator to form an electrode group, and the electrode group is inserted into a battery case. Thereafter, a predetermined amount of diluted sulfuric acid electrolyte was injected to produce a conventional sealed lead-acid battery (Y) of 2V10Ah.

Here, the cross section of the positive electrode grid of the sealed lead-acid battery (X) is composed of a first layer 51, a second layer 52, and a third layer 53, as shown in FIG. On the other hand, the cross section of the positive electrode grid of the sealed lead-acid battery (Y) includes a first layer 51 and a second layer 52 as shown in FIG.

The sealed lead-acid battery (X) and the sealed lead-acid battery (Y) were discharged with a discharge current of 2.5 A and a discharge end voltage of 1.
75V, charge current 2A, charge amount is 120% of discharge electricity amount
The battery was subjected to a charge / discharge cycle life test. At this time, the test was performed in a 50 ° C. water bath.

As a result of this test, the number of cycles in which the sealed lead-acid battery (X) reached the end of the life was about 50 cycles for all the test batteries, whereas the life of the sealed lead-acid battery (Y) reached the end of the life. As for the number of cycles, 70% of the cycles were about 50 cycles, and 30% were about 10 cycles.

All of these test batteries were disassembled after the end of the life test, and the positive electrode plate was taken out. Wash this positive electrode plate with water,
After drying, the epoxy resin was impregnated with the epoxy resin, and the epoxy resin including the positive electrode plate was cut and polished so that the cross section of the positive electrode plate could be observed, and the cross section of the positive electrode plate was observed.

As a result of this observation, it was found that the first layer and the second layer were separated from each other in a part of the sealed lead-acid battery (Y) whose life was early. In other sealed lead-acid batteries, peeling between the first and second layers or between the first, third and second layers was not observed. In particular, no peeling was observed in all of the sealed lead-acid batteries (X), so the third layer, which was softer than the first layer and the second layer, was not observed.
It is considered that the bonding between the first layer and the second layer became stronger due to the presence of the layer.

Example 2 A three-layer rolled sheet was manufactured by the method described in Example 1, and a grid was manufactured by punching. This grid was used as a positive electrode plate, and a sealed lead-acid battery similar to that of Example 1 was manufactured using the electrode plate shown in Example 1 as a negative electrode plate.

At this time, as a control, a two-layer rolled sheet was produced by the method shown in Example 1, and a grid was produced by punching. This grid was used as a positive electrode plate, and a sealed lead-acid battery similar to that of Example 1 was manufactured using the electrode plate shown in Example 1 as a negative electrode plate.

These batteries were subjected to the same test as in Example 1. As a result, about 40% of the batteries using the grid made of the control two-layer rolled sheet had an early decrease in capacity, whereas the batteries using the grid according to the present invention had no early capacity decrease. I was not able to admit.

At this time, in the battery which caused the early capacity decrease, the peeling of the first layer and the second layer was observed as in Example 1.

(Embodiment 3) Pb-1.0 wt.
The same test as in Example 1 was performed using% Sn (Vickers hardness 8). The results were almost the same as in Example 1.

[0039]

According to the present invention, a first layer made of a lead alloy, a second layer made of a lead alloy disposed on one side of the first layer, and a first layer formed between the first layer and the second layer. A third layer made of lead or a lead alloy, wherein the third layer is softer than the first layer and the second layer. And the bonding between the second layer and the first layer becomes stronger, preventing the second layer attached to the first layer from peeling off,
Consequently, the effect of attaching the second layer can be completely obtained. Thereby, the charge-discharge cycle life performance of the lead storage battery is stably improved.

[0040]

[Brief description of the drawings]

FIG. 1 is a diagram schematically illustrating a manufacturing process of a three-layer rolled sheet and an expanding process thereof (an example).

FIG. 2 is a diagram schematically illustrating a manufacturing process of a two-layer rolled sheet and an expanding process thereof (an example).

FIG. 3 shows a cross section of a grating according to the invention (one example).

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 11 Lead-calcium continuous casting board 12 Lead-calcium foil whose calcium concentration is higher than that of a lead-calcium continuous casting board 13 Pure lead foil corresponding to the third layer 21 Rolling roll 22 Expanding machine 31 Three-layer rolled sheet 32 Present invention Expanded lattice 41 Double-rolled sheet 42 Expanded lattice 51 by conventional method 51 First layer 52 Second layer 53 Third layer

Claims (8)

[Claims] 1. A first layer made of a lead alloy, a second layer made of a lead alloy disposed on one surface of the first layer, and a first layer formed between the first layer and the second layer. Third made of lead or lead alloy
Wherein the third layer is softer than the first layer and the second layer. 2. The grid for a lead-acid battery according to claim 1, wherein the second layer and the third layer are arranged only on one side of the first layer. 3. The grid according to claim 1, wherein the second layer and the third layer are disposed on both sides of the first layer. 4. The grid according to claim 1, wherein the third layer is made of pure lead or a lead-tin alloy. 5. The method according to claim 1, wherein the first layer is made of a lead-calcium alloy, and the second layer is made of a lead-calcium alloy having a higher calcium content than the first layer.
The grid for a lead storage battery according to claim 4. 6. The lead-acid battery grid according to claim 1, wherein the second layer and the third layer are integrated by pressure welding. 7. The method according to claim 1, wherein the device is manufactured by an expanding method or a punching method.
7. The grid for a lead-acid battery according to 4, 5, or 6. 8. The method of claim 1, 2, 3, 4, 5, 6, or 7.
A lead-acid battery using the lead-acid battery grid according to 1.