JPH0650648B2 - Sealed lead acid battery and manufacturing method thereof - Google Patents

Description

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

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, a storage battery in which an anode plate, a separator, and a cathode plate, which are square or rectangular in plan view, are arranged adjacent to each other on the same plane, and an electrolyte solution is housed in a storage battery case. Is proposed. An example of a structure that can be considered based on this is shown in FIG. (Conventional product) The battery thickness in this case is the sum of the thickness of the member having the largest thickness among the anode plate 1, the separator 4, and the cathode plate 10 and the thickness of the battery case 6, and the anode plate, the separator, and the cathode plate are laminated. The battery can be made thinner than the battery having the above structure.

Problems to be Solved by the Invention However, the above-mentioned sealed lead-acid battery has a problem when it is mounted on a portable device because its energy density is small. This is due to its structure and manufacturing method.
Since the anode plate 1, the cathode plate 10 and the separator 4'are adjacent to each other, the anode plate 1 and the cathode plate 10 facing each other via the separator 4'only contribute to discharge by the active material located on the side surface. If the area of the side surface is increased, the discharge capacity is increased, but the increase of the area of the side surface increases the thickness, which is not preferable.

Further, if the width of the anode plate 1, the cathode plate 10 and the separator 4'is made smaller, the discharge current density becomes smaller, and therefore the discharge capacity increases. Due to the danger, there is a limit in production technology.

Further, it is difficult in terms of production technology to keep the anode plate 1, the cathode plate 10 and the separator 4'adjacent to each other so as to maintain a good contact state at each interface, which is one of the causes of the small discharge energy density.

Due to the above-mentioned causes, the conventional battery has a low discharge energy density, which leaves a problem as a power source for portable devices. The present invention greatly improves this problem.

Means for Solving the Problems In the present invention, the positive electrode plate, the separator, and the negative electrode plate are not arranged adjacent to each other on the same plane, but the positive electrode active material is provided at least at one or more locations on a sheet-shaped or film-shaped current collector. Alternatively, either one of the cathode active materials is arranged, and the electrode plate on which the other active material is arranged is bonded to the portion where the active material is not arranged, through an insulating layer, and the sheet or film shape is formed. It is characterized in that an electrolyte holding layer is brought into contact with the current collector so as to surround the active material placed on the current collector. (Invention product 1) Further, a film-shaped insulating resin having at least one hole formed therein is joined to a sheet-shaped or film-shaped current collector, and an anode active material or a cathode active material is connected to the hole. One of the electrodes is disposed, and the electrode plate on which the other active material is disposed is joined to the resin portion, and the electrolyte holder is attached so as to wrap the active material disposed on the sheet-shaped or film-shaped current collector. It is characterized by being constructed in contact with each other. (Invention product 2) Action In the present invention, the anode active material or the cathode active material is arranged on a sheet-shaped or film-shaped current collector, and the electrolyte holding layer is arranged so as to wrap the current collector. The substance has a high utilization rate and a large capacity, and the fitting is easy because the electrolyte retaining layer is covered. In addition, by using a film-shaped insulating resin having holes for the insulating layer, it becomes easier to form the insulating layer, the capacity is less reduced, and the life characteristics are improved. Further, since one electrode plate is joined to the other current collector, the electrode plate is not displaced even when the battery case is inserted, and the adhesiveness with the electrolyte retaining layer is maintained.

Example 20 pieces of each of the present invention product 1, the present invention product 2 and the conventional product were prepared as a battery having a thickness of 1 mm.

In the product 1 of the present invention, as shown in FIGS. 1A and 1B, the cathode active material 3 is formed on the cathode current collector 2 made of lead or a lead alloy, and the cathode active material 3 is formed. The anode plate 1 is bonded to the non-existing portion via an insulating layer 5 (epoxy resin in this embodiment), and the electrolyte holding layer 4 is contacted so as to wrap the cathode active material 3 to form a group of electrode plates. The plate group was wrapped with a thermoplastic resin film, and the periphery of the film was heat-welded (heat-welded portion 8) to form a battery case 6 to obtain a battery.

As shown in FIGS. 2 (a) and 2 (b), the product 2 of the present invention comprises an insulating resin 9 of a polypropylene film (thickness 100 μm) in which holes are formed in the cathode current collector 2 made of lead or a lead alloy. And the cathode active material 3 is formed in the hole.
On the surface where the insulating resin 9 is not formed,
The anode plate 1 is joined and the electrolyte holding layer 4 is contacted so as to wrap the cathode active material 3 to form an electrode plate group. The electrode plate group is wrapped with a thermoplastic resin film and heat-welded around the film (heat-welded portion). 8) Then, the battery case 6 was formed to obtain a battery. still,
7 is a safety valve.

The conventional product is shown in FIG. 3, but the anode plate 1, the cathode plate 10 and the separator 4'are placed on one thermoplastic resin film, and another thermoplastic resin film is placed thereon. The two films are heat-welded around each other (heat-welded portion 8),
The battery case 6 was formed into a battery.

During the production of the conventional product, a phenomenon was observed in which the contact portion of the electrolyte retaining layer 4 with respect to the anode plate 1 and the cathode plate 10 was deviated during heat welding, which made the battery production difficult.

In each battery, the width of the active material was 5 mm, and the distance between the anode plate 1 and the cathode active material 3 was 5 mm.

The initial capacity of each of the 10 batteries was measured. Results are shown in FIG. The conventional product has a smaller capacity than the products 1 and 2 of the present invention, and the measured values have a large variation. This is because the anode plate, the cathode plate and the separator are arranged on the same plane, so that the anode plate, the cathode plate and the separator contact only on the side surface of the electrode plate, the contact area is small, the capacity is small, and It is difficult to fit the anode plate, cathode plate and separator,
This is because the fitting state is incomplete and the measured values vary. Further, the initial capacity of the product 2 of the present invention is slightly smaller than that of the product 1 of the present invention because the contact area between the active material and the electrolyte holding layer is equal to the thickness of the film-shaped insulating resin disposed on the surface of the current collector. Because it became smaller.

Next, a charge / discharge life test was performed on 10 cells of each battery under the conditions of discharge condition of 30 mA, discharge end voltage of 1.6 V, charge condition of 2.45 V constant voltage, limiting current of 15 mA, and 16 hr temperature of 25 ° C. Results are shown in FIG. The lives of the products 1 and 2 of the present invention were both about twice as long as that of the conventional product. This is because the conventional product has a small contact area between the anode plate, the cathode plate and the separator, which increases the discharge current density and accelerates the deterioration of the active material, and the fitting state is not uniform and the separator is not in close contact. This is because the anode active material becomes lead sulfate. Due to these reasons, the capacity decrease is accelerated.

EFFECTS OF THE INVENTION As described above, the products 1 and 2 of the present invention can have a high capacity and a long life, and the adhesion of the anode and the cathode electrolyte is not impaired by any method for forming the battery case. Therefore, it has a very high industrial value such as a small variation in characteristics.

[Brief description of drawings]

1 is a front view showing an embodiment of the present invention (product 1 of the present invention), (b) a sectional view taken along line AA, and FIG. 2 is another embodiment of the present invention (product 2 of the present invention). Indicates (a)
Front view, (b) BB cross-sectional view, FIG. 3 is a cross-sectional view showing a conventional sealed lead-acid battery (conventional product), FIG. 4 is a comparative view showing the results of the initial capacity test, and FIG. It is a comparison curve figure which shows the result of a discharge cycle life test. 1 is an anode plate, 2 is a cathode current collector, 3 is a cathode active material, 4 is an electrolyte holding layer, 5 is an insulating layer, 6 is a battery case, 7 is a safety valve, 8 is a heat-welded portion, 9 is an insulating resin, 10 is a cathode plate.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Satoshi Matsubayashi 2-1-1, Shinjuku-ku, Shinjuku-ku, Tokyo Inside Shin-Kindo Electric Co., Ltd. (72) Yasuhisa Wada 2-1-1, Nishishinjuku, Shinjuku-ku, Tokyo Michiko Sakai, Examiner, No. 1 Shinshin Todenki Co., Ltd.

Claims (4)

[Claims] 1. A sheet-shaped or film-shaped current collector having at least one or more of an anode active material or a cathode active material disposed therein, and a portion where the active material is not disposed, the other active material is disposed. The electrode on which the substance is arranged is joined via an insulating layer, and the electrolyte holding layer is configured to abut so as to wrap the active material arranged on the sheet-shaped or film-shaped current collector. A sealed lead acid battery. 2. The insulating layer is a film-shaped insulating resin, and is disposed in a portion of the sheet-shaped or film-shaped current collector where the active material is not disposed. The sealed lead acid battery according to item 1. 3. A sheet-shaped or film-shaped current collector having at least one or more positive electrode active materials or negative electrode active materials formed thereon, and the active material of the other is formed on a portion where the active material is not formed. A hermetically sealed type characterized in that an electrode plate on which a substance is formed is joined through an insulating layer, and an electrolyte holding layer is abutted so as to wrap the active material arranged on a sheet-shaped or film-shaped current collector. Lead-acid battery manufacturing method. 4. A sheet-shaped or film-shaped collector,
A film-like insulating resin having holes formed in at least one or more places is previously bonded, and either the anode active material or the cathode active material is formed in this hole, and this active material is not formed. 4. The method for manufacturing a sealed lead acid battery according to claim 3, wherein the electrode plate on which the other active material is formed is joined to the insulating resin portion.