JPH08241721A - Alkaline dry battery - Google Patents

Abstract

PURPOSE: To improve the discharge characteristic from low load to high load by forming a negative electrode by use of a zinc plate or a zinc plate having a specified hole in an alkaline dry battery. CONSTITUTION: In an alkaline dry battery, an electrode plate group formed by superposing a positive electrode plate 1 on a negative electrode 2 through a separator 2, and spirally winding them so that the positive electrode plate 1 is situated on the most outer circumference is constituted, and this is inserted to a battery case 4. A zinc plate is used as the negative electrode plate 3. The zinc plate has a number of holes, the porosity is set to about 5-70%, preferably, 20-70%, and either one of expand metal zinc plate and punching metal zinc plate is used. As the positive electrode plate 1, a metal oxide such as manganese dioxide is used. Thus, an alkaline storage battery excellent in high load discharge characteristic and having a negative electrode having a large discharge capacity can be provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an alkaline dry battery having zinc as a negative electrode.

[0002]

2. Description of the Related Art Conventionally, manganese dry batteries, alkaline manganese batteries and the like have been generally known as dry batteries having zinc as a negative electrode. The structure of the manganese dry battery has a structure in which can-shaped zinc is used as the negative electrode, and the positive electrode mixture is packed inside this via a separator. On the other hand, the structure of the alkaline manganese battery is opposite to that of the manganese dry battery, in which the positive electrode material mixture pellets are arranged on the outside and the gel-like powder zinc is packed inside via the separator. This is a so-called inside-out type structure. Alkaline manganese batteries are superior to manganese dry batteries in high-load continuous discharge performance.This is because alkaline manganese batteries use neutral aqueous solutions such as zinc chloride and ammonium chloride, while alkaline manganese batteries do not. Since a strong alkaline aqueous potassium hydroxide solution is used, the conductivity of ions is improved, and the negative electrode is powdered zinc, alkaline electrolyte,
Since it is a gelled negative electrode mixed with sodium polyacrylate or the like, it is considered that the diffusion of the electrolytic solution between the zinc particles occurs uniformly and advantageously throughout the negative electrode.

[0003]

In recent years, portable devices such as headphone stereos, CD players, and liquid crystal compact televisions that require high load discharge have become widespread. When existing dry batteries are used as the power source for these devices, Even with alkaline manganese batteries, which are said to excel in high load discharge, the discharge capacity is not satisfactory. This is a structure in which the alkaline manganese battery is superior to the above-mentioned high load discharge performance compared to the manganese dry battery, but since it is a battery structure called inside-out type, there is a limit in the electrode area of the positive and negative electrodes, This is because the electrode is sometimes overloaded and the utilization rate of the positive and negative electrodes is reduced.

[0004] The content of zinc per volume of the gelled negative electrode of an alkaline manganese battery is considerably smaller than the volume density 7.13 g / cm ³ of zinc metal alone at 2.03 g / cm ^3, the volume Percentage of zinc is 2
At 8%, the negative electrode filling capacity is considerably lower than that in the case of using zinc metal alone. However, it is advantageous to use a metallic zinc simple substance for the negative electrode as in the structure of a manganese dry battery in terms of the negative electrode filling capacity, but it is disadvantageous in terms of reactivity such as diffusion of the electrolytic solution.

The present invention has been made to solve the above problems, and an object of the present invention is to provide an alkaline dry battery provided with a negative electrode having excellent high load discharge characteristics and a large discharge capacity.

[0006]

In order to solve these problems, the alkaline dry battery of the present invention has a structure in which a negative electrode plate made of zinc and a positive electrode plate made of metal oxide are spirally wound with a separator interposed therebetween. In the alkaline dry battery, the negative electrode plate is a zinc plate. Furthermore, the zinc negative electrode plate has a large number of pores and has a porosity of 5% to 70%, preferably 20%.
% To 70%, and either an expanded metal zinc plate or a punched metal zinc plate is used. The metal oxide is manganese dioxide.

[0007]

[Function] Since the long zinc negative electrode plate is spirally wound with the positive electrode plate through the separator, the electrode area of the positive and negative electrode plates is significantly increased as compared with the inside-out type alkaline manganese battery. It can be expected that the discharge performance will be improved under high load. Further, since the positive electrode plate and the negative electrode plate are opposed to each other in a large area, even when using a zinc metal simple substance as the negative electrode plate, the diffusion of the electrolyte solution between the positive and negative electrodes occurs uniformly and advantageously,
The same effect as when using a gelled zinc negative electrode is obtained. That is, by using zinc metal alone as the negative electrode plate, the negative electrode filling capacity can be improved, and by making the long electrode plate a spiral structure, the electrode area increases, and the diffusion of the electrolyte solution is uniform and advantageous. Since this occurs, the discharge performance under high load can be improved.

Further, by providing a large number of holes in the zinc plate, it is expected that the electrolyte solution uniformly and advantageously diffuses through the holes to improve the zinc utilization rate. However, increasing the number of holes reduces the filling amount of zinc per volume and leads to a decrease in discharge capacity. For this reason, when using a zinc plate with holes, the upper limit of the porosity must be within 70%, which is equivalent to about 30% of the zinc content in the gel-like zinc powder, and is superior in discharge capacity. You will not be able to get sex.

[0009]

【Example】

(Embodiment 1) The present invention will be described below with reference to specific embodiments with reference to the drawings.

FIG. 1 is a structural sectional view of an alkaline dry battery to which the structure of the present invention is applied. In the figure, 1 is a positive electrode plate, which is formed by mixing and kneading manganese dioxide, carbon black and fluororesin into a sheet, and press-bonding this to a nickel expanded metal current collector, and 2 is made of cellophane and polypropylene. A separator 3 made of laminated non-woven fabric is a negative electrode plate made of metallic zinc. A battery in which the positive electrode plate 1 is superposed on the negative electrode plate 2 via the separator 3 and spirally wound so that the positive electrode plate comes to the outermost periphery, and the insulating resin plate 5 is placed at the bottom. The battery pack is inserted into the case 4, and the inner wall of the battery case contacts the outermost positive electrode plate to collect current. On the other hand, the negative electrode current collecting lead 7 is pulled from the negative electrode plate and welded to the negative electrode terminal plate 6 to collect current. Finally, an alkaline electrolyte is injected and the battery is sealed with a nylon sealing resin 8 to obtain the alkaline dry battery of the present invention.

The AA size alkaline dry battery A of the present invention produced by the above-mentioned constitution is used for the current value 1A, 500mA,
Discharge was performed with a continuous constant current of 100 mA and 10 mA. A 100 μm thick zinc foil was used for the negative electrode plate. Also,
As a comparative example, a conventional AA size alkaline manganese battery B was also discharged in the same manner. The result is shown in FIG. Figure 2
Is a load characteristic diagram of the battery, in which the horizontal axis represents the load current and the vertical axis represents the discharge capacity up to a battery voltage of 0.9 V, where A is the alkaline dry battery of the present invention and B is the conventional alkaline manganese battery.

As can be seen from this figure, the difference between the discharge capacities of battery A and battery B gradually increases as the load current value increases at high load discharge of 100 mA or more. This is because in the battery B, since the electrode area is small, as the load becomes higher, the rate of increase of the load applied to the electrode increases, the polarization of the battery increases, and as a result, the discharge capacity decreases. However, in the battery A, since the electrode area is large, the rate of increase in the load applied to the electrodes is small, and the polarization of the battery rarely occurs. Therefore, it is considered that the discharge capacity is less likely to decrease. In addition, the spirally wound structure causes the electrolyte of the negative electrode to uniformly and advantageously diffuse, and even when a zinc plate of a simple metal is used, the same effect as that of the gel zinc powder can be obtained. It is considered that the discharge performance under load could be improved.

Further, the discharge capacity under a low load of 100 mA or less is also slightly improved in Battery A as compared to Battery B. This can improve the negative electrode filling capacity by using zinc metal alone as the negative electrode. Probably because it was possible.

(Example 2) Next, an alkaline dry battery of the present invention similar to that of Example 1 was prepared by changing the porosity of the zinc plate.
A constant current discharge at A was performed. The result is shown in FIG. The zinc plate is the zinc foil having a porosity of 0% used in Example 1 and a thickness of 100 μm, and the porosities of 5% to 90% are prepared by expanding a zinc foil having a thickness of 100 μm to the porosity. is there.

As can be seen from this figure, the zinc plate having a porosity of 5% improves the utilization factor of the negative electrode by 10% or more as compared with the zinc foil having no porosity of 0%. However, the porosity is 5% to 2
At 0%, the improvement of the negative electrode utilization rate with the increase of the porosity is small, and at 20% or more, there is almost no change in the negative electrode utilization rate. It is considered that this is because by forming holes in the zinc plate, the diffusion of the electrolyte solution of the negative electrode progresses through the holes, and the utilization rate of the negative electrode during discharge at 1 A, which is a high load discharge, is improved. In particular, the effect is great when the porosity is 5% or more. However, increasing the number of pores reduces the filling amount of zinc per volume, which also leads to a decrease in discharge capacity. For this reason, in order to use a zinc plate with holes, the upper limit of the porosity must be within 70%, which is equivalent to about 30% of the zinc content in the gel zinc powder, and the low porosity of Example 1. It is not possible to obtain the superiority in the discharge capacity of the battery A over the battery B in discharging under load. Therefore, the porosity of the zinc plate is 5% to 70%, preferably 20% to 7
It is better to set it to 0%.

With respect to the negative electrode zinc plate, the expanded metal zinc plate was used in Example 2, but the same effect was obtained with the punched metal zinc plate.

[0017]

As is apparent from the above description, by spirally winding the zinc plate together with the positive electrode via the separator as in the present invention, the electrode area is increased and the diffusibility of the electrolytic solution is improved. Moreover, since the negative electrode filling amount is improved by using the zinc plate, it is possible to supply an alkaline dry battery excellent in discharge performance from low load to high load. Further, the porosity is 5% to 70%, preferably 20% to 7
If a 0% zinc plate is used, the high load discharge performance is further improved.

[Brief description of drawings]

FIG. 1 is a structural cross-sectional view of an alkaline dry battery according to the present invention.

FIG. 2 is a diagram showing a comparison of discharge load characteristics between an alkaline dry battery according to the present invention and a conventional alkaline manganese battery.

FIG. 3 is a diagram showing a relationship between a porosity of a zinc plate and a negative electrode utilization rate in a constant current discharge of 1 A of an alkaline dry battery according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Positive electrode plate 2 Separator 3 Negative electrode plate 4 Battery case 5 Insulating resin plate 6 Negative electrode terminal plate 7 Negative electrode current collecting lead 8 Nylon sealing resin

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shigeo Kobayashi 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) In Jun Jun Nume, 1006 Kadoma, Kadoma City, Osaka

Claims (6)

[Claims] 1. An alkaline dry battery in which a negative electrode plate made of zinc and a positive electrode plate made of metal oxide are spirally wound with a separator in between, and the negative electrode plate is made of a zinc plate. Alkaline battery. 2. The alkaline dry battery according to claim 1, wherein the zinc plate has a large number of holes. 3. The alkaline dry battery according to claim 1, wherein the zinc plate has a porosity of 5% to 70%. 4. The alkaline dry battery according to claim 1, wherein the zinc plate has a porosity of 20% to 70%. 5. The alkaline dry battery according to claim 1, wherein the zinc plate is an expanded metal zinc plate or a punching metal zinc plate. 6. The alkaline dry battery according to claim 1, wherein the metal oxide is manganese dioxide.