JPH05325975A - Thin type lead acid battery - Google Patents

Abstract

PURPOSE:To provide a thin type lead acid battery whose life can be extended by improving adhesion of an interface between a collector and an active material when a lead or lead alloy sheet is used as the collector. CONSTITUTION:Many protrusive parts 7, 8 in sheet thickness or more of collectors are dispersedly provided in the collectors 4, 5 consisting of a lead or lead alloy sheet. Opening parts 9, 10 are respectively provided in these protrusive parts 7, 8. A positive electrode active material 2 is applied in height or more of the protrusive part 7 to the collector 14. A negative electrode active material 3 is applied in height or more of the protrusive part 8 to the collector 5. The collectors 4, 5 of applying these active materials 2, 3 are arranged in both sides of an electrolyte supporter 1, to store these laminated units in a bag-shaped outer sheath film 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thin lead storage battery using a lead or lead alloy sheet as a current collector.

[0002]

2. Description of the Related Art FIG. 4 shows the structure of a conventional thin lead-acid battery of this type. In the thin lead acid battery,
A positive electrode active material 2 and a negative electrode active material 3 are laminated on both sides of the electrolytic solution holder 1, and a lead or lead alloy sheet is used for the surface of the layer of the positive electrode active material 2 and the surface of the layer of the negative electrode active material 3. Electric body 4, 5
Was provided, and these laminated bodies were housed in the bag-shaped exterior film 6. Each of the current collectors 4 and 5 is adhesively fixed to the inner surface of the exterior film 6.

Cast grids and expanded grids have been used as the current collectors 4 and 5 of such conventional thin lead-acid batteries, but the size and thickness of the electrode plates have recently become smaller and thinner. I have to make it thinner. However, casting grids and expanded grids have a limit in thinning, and lead sheets and punched metal grids punched from them have been used as current collectors.

[0004]

However, when a lead or lead alloy sheet is used as the current collector, the adhesion of the interface between the lead or lead alloy sheet and the active material is inferior to that of a casting grid or the like as it is. However, there was a problem of short life.

An object of the present invention is to improve the adhesion of the interface between the current collector and the active material when using a lead or lead alloy sheet as the current collector, and to extend the life of the thin lead acid battery. To provide.

[0006]

The constitution of the present invention which achieves the above object will be described as follows.

According to the first aspect of the invention, a layer of the positive electrode active material and a layer of the negative electrode active material are arranged on both surfaces of the electrolytic solution holder,
In a thin lead-acid battery in which current collectors made of lead or a lead alloy sheet are arranged on the outside of each of these, and a laminate of these is housed in an exterior film, the current collector has a convex portion having a sheet thickness or more. Are provided in a dispersed manner, each of the convex portions is provided with an opening, and the current collector is coated with an active material at a height equal to or higher than the height of the convex portion.

According to a second aspect of the present invention, in the first aspect, the area of the opening of each of the convex portions is 10% to 60% of the total area of one electrode plate. To do.

[0009]

According to the first aspect of the present invention, the current collector is provided with a large number of projections having a thickness equal to or larger than the sheet thickness, and the projections are provided with openings, respectively. When the active material is applied to a height or more, the active material enters into the openings of the protrusions, and the adhesion at the interface between the current collector and the active material is improved.
In addition, since the active material is held in the openings of the convex portions of the current collector, the active material can be prevented from cracking, falling off, or peeling, and the life can be extended.

When the area of the opening of each convex portion is 10% to 60% with respect to the total area of one electrode plate, the life cycle number of the thin lead acid battery is defined. Can be further increased.

[0011]

1 and 2 show one embodiment of a thin lead acid battery according to the present invention. The parts corresponding to those in FIG. 4 described above are denoted by the same reference numerals.

In the thin lead-acid battery of this embodiment, current collectors 4 and 5 made of a lead or lead alloy sheet are provided with a large number of projections 7 and 8 having a thickness equal to or larger than the sheet thickness. The portions 7 and 8 are provided with openings 9 and 10, respectively. The positive electrode active material 2 is applied to the current collector 4 at a height equal to or higher than the height of the convex portion 7. Further, the negative electrode active material 3 is applied to the current collector 5 at a height equal to or higher than the height of the convex portion 8. These active materials 2,
The current collectors 4 and 5 to which 3 is applied are arranged on both sides of the electrolytic solution holder 1, and these laminates have a bag-shaped exterior film 6
It is housed inside.

Next, such a thin lead acid battery of the present invention and a conventional thin lead acid battery having a current collector having no protrusions and openings were prepared and comparative experiments were conducted.

As a conventional thin lead-acid battery having the structure shown in FIG. 4, the thickness of the current collectors 4 and 5 is 0.1 mm, and the active materials 2 and 3 are
The thickness of both the positive and negative electrodes was 0.5 mm, the thickness of the electrolytic solution holder 1 was 0.6 mm, the thickness of the exterior film 6 was 0.1 mm, and the total battery thickness was 2 mm.

As an example of the thin lead-acid battery of the present invention shown in FIG. 1, the openings 9, 10 are 5%, 10%, 25%, 40% of the total area of the current collectors 4, 5. 50%, 60%, 75%, 90%
Current collectors 4 and 5 are prepared and the height of the convex portions 7 and 8 is 0.4 mm.
And The shape of the openings 9 and 10 is a circle having a diameter of 3 mm this time, but the shape is not limited to this. The thicknesses of the electrolytic solution holder 1, the active materials 2 and 3, the current collectors 4 and 5, and the exterior film 6 were exactly the same as those of the conventional thin lead acid battery.

All of these batteries were put into a cycle life test. The results are shown in Fig. 3. The cycle conditions are as follows.

Discharge: 0.4 C constant current discharge (F.V: 1.6 V) Charge: 2.45 V (0.3 C limited current) constant current constant voltage Pause: 1 h Ambient temperature: 25 ± 2 ° C

The life was judged to have reached 50% of the initial capacity. From Fig. 3, it can be seen that the life reached to 100 cycles when the aperture ratio was 0%, but the number of cycles gradually increased until the aperture ratio was 40%, but the number of cycles gradually decreased after that. Achieving the target of 200 cycles was a battery having an aperture ratio of 10% to 60%. Aperture ratio is 5%
The reason why the cycle number is small is that the opening areas of the openings 9 and 10 are small and the active materials 2 and 3 are peeled off. When the aperture ratio is 75% or more, the space between the adjacent apertures 9 and 10 becomes very narrow, and it is considered that the service life was extended due to corrosion of the current collectors 4 and 5 during charging and discharging.

[0019]

As described above, according to the thin lead acid battery of the present invention, the following effects can be obtained.

According to the first aspect of the invention, a current collector made of a lead or lead alloy sheet is provided with a large number of projections having a thickness equal to or larger than the sheet thickness, and the projections are provided with openings, respectively. Since the active material is applied to the current collector so as to have a height higher than the height of the convex portion, the active material enters the opening of the convex portion, and the adhesion at the interface between the current collector and the active material can be improved. In addition, since the active material is held in the openings of the convex portions of the current collector, the active material can be prevented from cracking, falling off, or peeling, and the life can be extended.

According to the second aspect of the present invention, the area of the opening of each convex portion is 10% to 60% with respect to the total area of one electrode plate.
Therefore, the life cycle number of the thin lead acid battery can be further increased.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an embodiment of a thin lead acid battery according to the present invention.

FIG. 2 is a plan view of a current collector used in the embodiment of FIG.

FIG. 3 is a diagram showing the relationship between the aperture ratio of a current collector and the number of life cycles.

FIG. 4 is a cross-sectional view showing an example of a conventional thin lead-acid battery.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Electrolyte holding body 2 Positive electrode active material 3 Negative electrode active material 4,5 Current collector 6 Exterior film 7,8 Convex part 9,10 Opening part

Claims (2)

[Claims] 1. A layer of a positive electrode active material and a layer of a negative electrode active material are arranged on both sides of an electrolytic solution holder, and current collectors made of lead or a lead alloy sheet are arranged on the outer sides of these layers, respectively, and a laminate of them is provided. In a thin lead-acid battery in which a body is housed in an exterior film, a large number of convex portions having a sheet thickness or more are provided dispersedly on the current collector, and each convex portion is provided with an opening, respectively.
A thin lead acid battery, wherein the current collector is coated with an active material at a height higher than the height of the convex portion. 2. The thin lead acid battery according to claim 1, wherein the area of the opening of each of the convex portions is 10% to 60% with respect to the total area of one electrode plate.