JPH0260068A - Sealed lead-acid battery - Google Patents

Abstract

PURPOSE:To enhance capacity, to lengthen life, and to make thin by forming a cathode active material on a resin sheet through a current collector and forming an anode active material in the same way, and stacking the resin sheets so as not to face each active material, then heat-bonding the circumferences of the resin sheets. CONSTITUTION:A cathode plate is formed by arranging cathode active materials 2 on one side of a film or sheet-shaped cathode current collector 1 made of lead or lead alloy, and connecting the current collector 1 to a resin film or sheet 6. An anode plate is formed by similarly arranging anode active materials 4 on one side of a current collector 3 and connecting the current collector 3 to a resin film or sheet 6. Both resin sheets are stacked through a separator 5 retained with an electrolyte so as not to face active materials 2, 4, then the circumferences of the resin sheets 6 are melt-bonded. The active materials are in contact with the electrolyte on the upper side in addition to both sides, and discharge capacity is increased. Since the cathode and the anode come in each other without facing, a battery is made thin.

Description

[Detailed description of the invention] Industrial applications The present invention relates to making a sealed lead-acid battery thinner.

BACKGROUND OF THE INVENTION In recent years, as portable devices have become thinner, there has been an increasing demand for thinner lead-acid batteries, which are their power source. Under these circumstances, an electrode plate group consisting of an anode plate, a separator, and a cathode plate, all of which are square or rectangular in plan view and arranged adjacent to each other on the same plane, and an electrolyte were housed in a storage battery case. Storage batteries have been proposed. An example of a possible structure based on this is shown in FIG. Hereinafter, it will be referred to as "conventional product 2." In this case, the battery thickness is the sum of the thickness of the thickest member of the anode plate, the seven-four-layer cathode plate, and the thickness of the battery case. This battery can be made thinner than the battery (conventional product 1).

Problems to be Solved by the Invention However, the above-mentioned sealed lead-acid battery poses a problem when mounted in a portable device due to its low energy density. This is due to its structure and manufacturing method.

Because the anode plate, the cathode plate, and the seven-node plate are adjacent to each other and in contact with each other,
In both the anode plate and the cathode plate, which face each other with a separator in between, only the active material located on the side surfaces contributes to the discharge. Increasing the area of the side surfaces increases the discharge capacity, but increasing the area of the side surfaces increases the thickness, which is not preferable.

Also, if the widths of the anode plate, cathode plate, and separator are made smaller, the discharge current density will be reduced, and the discharge range will increase, but if the width is too small, the accuracy will be compromised.
Due to the risk of short circuit, there are limits to production technology.

Furthermore, the method of arranging the anode plate, cathode plate, and separator so that they are adjacent to each other is difficult due to production technology, and the fitting condition of each component, the interface between the anode plate and the separator, and the separation between the cathode plate and the separator are difficult. The adhesion state of the interface with the rotor was incomplete.

Due to the reasons described above, conventional batteries have a low discharge energy density, which remains a problem as a power source for portable devices. The present invention significantly improves this problem.

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention provides an anode current collector in the form of a film or a sheet, in which the current collector side of the anode plate is bonded on one side of which an anode active material is formed. A film-like or sheet-like resin that has been bonded to the current collector side of a cathode plate having a cathode active material formed on one side of a film-like or sheet-like cathode current collector. Overlaid with a separator in between,
It is characterized in that the anode active material and the cathode active material do not face each other with a separator in between, and the resin is thermally welded around the resin.

By taking the above-mentioned measures, the battery is 1.
The present invention has the following features: (1) Not only the side surfaces but also the top surfaces of the electrode plates come into contact with the separator holding the electrolyte, so the active material reaction area increases and the discharge capacity increases.

■ Good adhesion can be obtained between the active material and the separator by simply inserting the separator between the electrode plates and heat welding the surrounding area.

■ Because the anode and cathode do not face each other with a separator in between,
It becomes possible to make it thinner.

EXAMPLE A sealed lead-acid battery (product of the present invention) based on an embodiment of the present invention and a sealed lead-acid battery based on the prior art were each made with a thickness of 1 m, and their performance was evaluated.

The product of the present invention is as shown in FIGS. 1 and 4.

Anode active material 2 is formed on one side of a film-like or sheet-like anode current collector 1 made of lead or lead alloy, and a film-like or sheet-like resin 6 is bonded to the current collector 1 side of the anode plate. , a film-like or sheet-like resin 6 to which the current collector 3 side of the cathode plate is bonded, and a cathode active material 4 is formed on one side of a film-like or sheet-like cathode current collector 3 made of lead or a lead alloy. The anode active material 2 and the cathode active material 4 do not face each other with the separator 5 in between, and the surrounding resin 6 is thermally welded. The thickness of the resin that becomes the battery case is 0.1 rtm.

Current collector thickness is 0.1 rpa, active material thickness is 0.4
m, and the thickness of the separator located on the active material is 0.3
As rtrra, the total thickness was set to 1.0 fl.

Sealed lead-acid battery with stacked group structure based on conventional technology (
A cross-sectional view of the conventional product 1) is shown in FIG.

The thickness of the battery case is 0.1mm, the thickness of the current collector is 0.1mm, the thickness of the active material is 0.2rtm, the thickness of the semi-4 layer is 0.2mm, and the total thickness is 1mm. It was Otma.

In addition, the thickness of the battery case made as conventional product 2 in Fig. 3 is 0.1 m, the thickness of the current collector is 0.1 m, and the thickness of the active material is 0.1 m.
7 +, m and the total thickness was LOrxs"'C$.

Note that the electrode plate width of the present invention product and the conventional product 2 was 50 mm, and the distance between the positive plate and the negative plate was 50 mm.

Create 20 cells each of the above three types of batteries and generate 30 mA.
A discharge test was conducted. The results are shown in Figure 5. Although the product of the present invention had a slightly inferior capacity compared to conventional product 1, it had a capacity more than twice that of conventional product 2, and its initial capacity was good.

Next, a charge/discharge cycle test was conducted under the test/fail conditions shown below to examine the life performance, and the results are shown in FIG.

The product of the present invention has a lifespan approximately 1.5 times longer than conventional product 1.

Moreover, compared to conventional product 2, it had a life performance that was more than twice as long.

The reason why the initial capacity and life performance of Conventional Product 2 are not good is that the contact area between the active material and the separator is small and the adhesion between these interfaces is not good.

Conventional product 1 has a good initial capacity, but the capacity decreases significantly with charge and discharge cycles.This is because the active material layer is thin, so the adhesion between the current collector and the active material deteriorates with charge and discharge. This is due to early damage due to changes in the form of the active material.

In contrast, the product of the present invention does not have the drawbacks that conventional products have, so it is a sealed lead-acid battery with high capacity and long life.

Effects of the Invention The sealed lead-acid battery according to the present invention has great industrial value in that it can be easily made thin, has a high capacity, and has a long life.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an embodiment of the present invention, FIGS. 2 and 3 are sectional views of a conventional sealed lead-acid battery, and FIG. 4 is a sectional view of a conventional sealed lead acid battery.
FIG. 5 is a schematic diagram showing the assembled state of the product of the present invention, FIG. 5 is a comparison diagram showing the initial capacity test results, and FIG. 6 is a comparison curve diagram showing the charge/discharge cycle test results. Figure 1 Figure 2 Figure 3 Figure 5 Figure 4 Figure 6 Number of charge/discharge cycles

Claims (1)

[Claims] An anode active material is formed on one side of a film or sheet anode current collector; a film or sheet resin to which the collector side of the anode plate is bonded; and a film or sheet cathode current collector. A cathode active material is formed on one side of the cathode plate, and a film or sheet resin is bonded to the current collector side of the cathode plate, which is layered with a separator in between. A sealed lead-acid battery characterized in that the materials do not face each other and the resin is thermally welded around the resin.