JPH0693365B2 - Sealed lead acid battery - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thinner sealed lead acid battery.

2. Description of the Related Art As portable devices have become thinner in recent years, there has been an increasing demand for thinner lead-acid batteries as their power source.
Under such circumstances, the electrode plate group and the electrolytic solution, which are square or rectangular when viewed from the plane and are arranged adjacent to each other on the same plane, are placed in the storage battery case. Storage batteries have been proposed. An example of a structure that can be considered based on this is shown in FIG. Hereinafter referred to as "conventional product 2". The battery thickness in this case is the sum of the thickness of the thickest member of the anode plate, the separator, and the cathode plate and the thickness of the battery case, and the battery having the structure in which the anode plate, the separator, and the cathode plate are laminated (conventional product) It can be made thinner than 1).

Problems to be Solved by the Invention However, the sealed lead-acid battery of the conventional product 2 described above has a problem because its energy density is small when mounted in a portable device. This is due to its structure and manufacturing method. Since the anode plate, the cathode plate and the separator are adjacent to each other, the anode plate and the cathode plate facing each other through the separator are
In both cases, only the active material located on the side surface contributes to the discharge. If the area of the side surface is increased, the discharge capacity is increased, but the increase of the side surface area is increased in thickness, which is not preferable.

Also, if the width of the anode plate, the cathode plate, and the separator are made smaller, the discharge current density becomes smaller, so the discharge capacity increases, but if this width is too small, the accuracy may be considerably poor, and there is a risk of short circuit. Therefore, there is a limit in production technology.

Furthermore, it is also difficult in terms of production technology to arrange the anode plate, the cathode plate, and the separator adjacent to each other, and the fitting state of each component, that is, the interface between the anode plate and the separator and the interface between the cathode plate and the separator are difficult. Was incomplete.

Due to the causes described above, in the conventional battery (conventional product 2),
The discharge energy density was small, leaving a problem as a power source for portable devices. The present invention greatly improves this problem.

Means for Solving the Problems The present invention is a sealed lead-acid battery in which two resin films or resin sheets are joined together at their peripheries to enclose a power generating element inside, and one resin film or resin sheet A film-shaped or sheet-shaped anode current collector is formed in a pattern on the inner surface, and an anode active material is formed on the pattern of the anode current collector, and a film-shaped film is formed on the inner surface of the other resin film or resin sheet. Alternatively, a sheet-shaped cathode current collector is formed in a pattern, and a cathode active material is formed on the pattern of the cathode current collector, and the two resin films or resin sheets are separators holding an electrolytic solution. And the patterns of the positive electrode active material and the negative electrode active material are arranged so as not to face each other with the separator interposed therebetween, is there.

By taking the above-mentioned measures, compared to conventional batteries,
In the present invention, not only the side surface but also the upper surface of the electrode plate contacts the separator holding the electrolytic solution, so that the active material reaction area increases and the discharge capacity increases.

Good sandwiching between the active material and the separator can be achieved simply by sandwiching the separator between the electrode plates and joining the periphery by heat welding or the like.

Since the anode and the cathode do not face each other via the separator, it is possible to make the device thinner.

Example A sealed lead-acid battery (invention product) based on a practical example of the present invention
Then, a sealed lead-acid battery based on the conventional technology was prepared with a thickness of 1 mm each, and the performance was evaluated.

In the product of the present invention, as shown in FIGS. 1 and 4, an anode active material 2 is formed on one surface of an anode current collector 1 formed of lead or a lead alloy in a film-like or sheet-like pattern. A film- or sheet-like resin 6 in which the current collector 1 side of the anode plate is joined, and a cathode or collector on one surface of a cathode current collector 3 formed in a film- or sheet-like pattern made of lead or lead alloy. A film-like or sheet-like resin 6 to which the current collector 3 side of the cathode plate on which the active material 4 is formed is joined via a separator 5, and the anode active material 2 and the cathode active material are interposed via the separator 5. Four
Were not opposed to each other, but were formed by heat welding the surrounding resin 6. The thickness of the resin used as the battery case was 0.1 mm, the thickness of the current collector was 0.1 mm, the thickness of the active material was 0.4 mm, the thickness of the separator located on the active material was 0.3 mm, and the total thickness was 1.0 mm.

FIG. 2 shows a cross-sectional view of a sealed lead-acid battery (conventional product 1) having a laminated group structure based on the conventional technique. Battery case thickness is 0.
The thickness was 1 mm, the current collector thickness was 0.1 mm, the active material thickness was 0.2 mm, the separator thickness was 0.2 mm, and the total thickness was 1.0 mm.

Moreover, the battery case thickness of the conventional product 2 shown in FIG. 3 was 0.1 mm, the collector thickness was 0.1 mm, the active material thickness was 0.7 mm, and the total thickness was 1.0 mm. The electrode plate width of the product of the present invention and the conventional product 2 is 5 mm, and the distance between the anode plate and the cathode plate in the plane direction is 5 mm.
And

The above three types of batteries were prepared for each 20 cells and a 30 mA discharge test was conducted. The results are shown in Fig. 5. The product of the present invention has a capacity slightly inferior to that of the conventional product 1, but has twice or more the capacity of the conventional product 2 and the initial capacity was good.

Then, a charge / discharge cycle test was performed under the following test conditions to examine the life performance, and the results are shown in FIG.

The product of the present invention had a life of about 1.5 times as long as that of the conventional product 1 and more than twice as long as that of the conventional product 2.

The reason why the initial capacity and the life performance of the conventional product 2 are not good is that the contact area between the active material and the separator is small and the adhesion at the interface between them is not good.

The conventional product 1 has a good initial capacity, but the capacity decreases greatly with charge / discharge cycles. This is because the active material layer is thin, and the adhesion between the current collector and the active material is associated with charge / discharge. This is because the active material loses its shape early due to a change in its shape.

On the other hand, the product of the present invention does not have the drawbacks that the conventional product has, and thus becomes a sealed lead acid battery with high capacity and long life.

EFFECTS OF THE INVENTION The sealed lead-acid battery based on the present invention has a great industrial value in that it can be easily thinned, has a high capacity, and has a long life.

[Brief description of drawings]

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.
FIG. 5 is a schematic diagram showing an assembled state of the product of the present invention, FIG. 5 is a comparative diagram showing an initial capacity test result, and FIG. 6 is a comparative curve diagram showing a charge / discharge cycle test result.

Continuation of the front page (72) Inventor Satoshi Matsubayashi 2-1-1, Nishishinjuku, Shinjuku-ku, Tokyo Michiko Sakai, Examiner, Shin-Kindo Electric Co., Ltd.

Claims (1)

[Claims] 1. A sealed lead-acid battery in which two resin films or resin sheets are joined together at their peripheries to enclose a power generating element inside, wherein one of the resin films or resin sheets has a film-like or A sheet-shaped anode current collector is formed in a pattern,
An anode active material is formed on the pattern of the anode current collector, and a film-shaped or sheet-shaped cathode current collector is formed in a pattern on the inner surface of the other resin film or resin sheet. A cathode active material is formed on the pattern, the two resin films or resin sheets are stacked via a separator holding an electrolytic solution, and the pattern of the anode active material and the cathode active material The sealed lead-acid battery is characterized in that the two are arranged so as not to face each other via the separator.