JP2000048799A - Battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To low and stably keep contact resistance between an electrode surface of a terminal part and an electrode terminal of battery using equipment by forming a nickel - tin alloy layer on the surface of at least the outer side of a terminal part of a negative electrode and/or a positive electrode. SOLUTION: A negative terminal plate 13 has a iron - nickel alloy layer 19 formed by heat treatment on the interface between the whole surface of a steel plate 17 acting as a base plate and a nickel plating layer 18. A tin plating layer formed on the outer surface of the nickel plating layer 18, acting as an electrode surface of the negative terminal plate 13 is converted into a nickel - tin alloy layer 14 in a heat treatment process. Tin having contact resistance lower than nickel is used in the nickel - tin alloy layer 14 on the electrode surface (outer surface) electrically connected by contact with an electrode terminal on the negative side of battery using equipment. The nickel - tin alloy layer 14 has high hardness, falling down of abrasion powder produced by rubbing of the negative terminal plate 13 with a battery using equipment terminal is decreased, and increase in contact resistance caused by oxidation of the abrasion powder can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a battery such as an alkaline battery.

[0002]

2. Description of the Related Art Generally, an alkaline battery has the following structure. That is, a positive electrode mixture formed into a cylindrical shape is inserted into a headed cylindrical battery case having a positive electrode terminal integrally protruded from the upper end surface and an outer label attached to the outer peripheral surface. A gel zinc negative electrode is injected inside the agent with a separator interposed. In the sealing unit body for sealing the opening at the bottom of the battery case, the negative electrode current collector is pressed into the insertion hole of the resin gasket and attached in a protruding state, and a metal insulating washer is fitted into the gasket. Then, the central part of the negative electrode terminal plate is attached to the electrode part at the head of the negative electrode current collector in an electrically connected state by spot welding and assembled.

[0003] After the sealing unit is inserted into the bottom opening of the battery case, the bottom opening end of the battery case is bent inward and caulked to form a folded portion formed in the sealing gasket. The opening of the battery case is hermetically sealed by being strongly pressed by the negative electrode terminal plate.

[0004]

However, since the negative electrode terminal plate of the battery is generally formed by rolling a nickel-plated rolled steel plate into a required shape,
When this battery is loaded in a battery-powered device, the contact resistance between the outer electrode surface of the negative electrode terminal plate and the negative electrode terminal mainly composed of a coil spring in the battery-powered device is relatively high, and this is the This is a factor that shortens the usable time.

Therefore, it is conceivable to form a negative electrode terminal plate using a rolled steel plate in which tin having a smaller contact resistance than nickel is plated on the surface of an iron material. However, since tin is soluble in an alkaline solution used as an electrolytic solution of an alkaline battery, it may corrode when used in an alkaline battery. is there. In addition, since tin plating has a relatively low surface hardness, when the battery is subjected to vibration in a state where the battery is loaded in a battery-powered device, the tin plating layer of the negative electrode terminal plate is rubbed against the negative electrode terminal of the battery-powered device and falls off. The dropped fine powder is oxidized to increase the contact resistance.

Accordingly, an object of the present invention is to provide a battery capable of stably maintaining a contact resistance between an electrode surface of a terminal portion and an electrode terminal of a battery-using device at a low value.

[0007]

In order to achieve the above object, in the battery of the present invention, a nickel-tin alloy layer is formed on at least the outer surface of the negative electrode and / or the positive electrode terminal.

In this battery, a nickel-tin alloy layer using tin having a smaller contact resistance than nickel is formed on an outer surface of a terminal portion, which is in contact with an electrode terminal of a battery-using device and is electrically connected thereto. Therefore, the contact resistance between the nickel-tin alloy layer and the electrode terminals of the battery-powered device becomes smaller than that of the conventional battery, and the usable time of the battery-powered device becomes longer accordingly. In addition, the nickel-tin alloy layer has a high hardness characteristic characteristic of an intermetallic compound of nickel and tin, and has a high surface hardness. The electrode terminals of the device do not fall off due to rubbing. Moreover, the outer surface of the terminal portion is improved in both alkali resistance and corrosion resistance to salt water due to the presence of the intermetallic compound of the nickel-tin alloy layer, so that it can be applied to an alkaline battery injected with an alkaline electrolyte without any problem. it can.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a longitudinal sectional view showing an alkaline battery according to one embodiment of the present invention. In the figure, a headed cylindrical battery case 1 has a positive electrode terminal 2 integrally projecting from the upper end surface thereof, and a heat-shrinkable outer label 3 covered on the outer peripheral surface by means of sticking and heat-shrinking. I have. A positive electrode mixture 4 formed into a cylindrical shape with manganese dioxide and graphite added as a conductive material is inserted into the battery case 1. Inside the positive electrode mixture 4, a gelled zinc negative electrode 7 in which a zinc alloy powder is uniformly dispersed together with a gelling agent in an alkaline electrolyte in which potassium hydroxide is dissolved is injected via a separator 8. .

An opening at the bottom of the battery case 1 is hermetically sealed by a sealing unit 9. After the washer 12 is fitted into the resin gasket 10, the sealing unit body 9 is held in a state where the rod-shaped negative electrode current collector 11 made of brass is inserted into the insertion hole 10 a of the resin gasket 10 so as to protrude from the gasket 10. And a negative electrode current collector 11
A negative electrode terminal plate (terminal portion) 13 is fixed to a central portion of the electrode portion 11a of the head portion in an electrically connected state by spot welding. The opening of the battery case 1 is connected to the sealing unit 9 assembled as described above.
After the negative electrode current collector 11 is inserted with the negative electrode collector 11 facing inward, the peripheral edge of the bottom opening of the battery case 1 is bent inward and caulked, so that the crimping portion 1a formed by the opening forms The folded portion 10b formed on the gasket 10 is strongly pressed by the negative electrode terminal plate 13 and is sealed in a sealed state.

The negative electrode terminal plate 13 is characterized in that a nickel-tin alloy layer 14 is formed on the outer electrode surface. Next, a manufacturing process of the negative electrode terminal plate 13 will be described with reference to a flowchart of FIG. First, a steel plate such as a steel plate is rolled to form a steel plate having a predetermined thickness (step S1), and the entire surface of the steel plate is nickel-plated to form a nickel plating layer (step S2). At this time, the nickel plating layer is deposited and formed so that the thickness of the outer surface serving as the electrode surface is 25 μm and the thickness of the inner surface facing the inside of the battery is 35 μm.

Next, tin plating is applied only to the outer surface of the above-mentioned nickel-plated steel sheet when it is used as the negative electrode terminal plate to form a plating layer having a thickness of 0.2 μm (step S3). Then, in a temperature environment of 500 to 700 ° C,
A heat treatment is performed for 10 hours (step S4). In this embodiment, the heat treatment was performed in a temperature environment of 600 ° C. for 8 hours. Thereafter, rolling is performed again (step S5), and a steel plate having a predetermined thickness is formed by pressing or the like (step S6), whereby the negative electrode terminal plate 13 is manufactured.

FIG. 3 is a cross-sectional view of the negative electrode terminal plate 13 manufactured through the above manufacturing steps, cut in the thickness direction. In the figure, the negative electrode terminal plate 13 is provided with a steel plate 17 serving as a core material.
An iron-nickel alloy layer 19 is formed at the boundary between the entire surface of the nickel plating layer 18 and the nickel plating layer 18 by the above-described heat treatment step. The tin-plated layer becomes the above-described nickel-tin alloy layer 14 by the heat treatment step.

The alkaline battery of the embodiment provided with such a negative electrode terminal plate 13 has an electrode surface (an outer surface) which is electrically connected to the negative electrode terminal of the battery-using equipment in the negative terminal plate 13. Since the nickel-tin alloy layer 14 using tin having a smaller contact resistance than nickel is formed on the surface (the surface), the contact resistance between the nickel-tin alloy layer 14 and the negative electrode terminal is determined by the negative electrode of the conventional battery. It becomes smaller than the nickel plating layer formed on the electrode surface of the terminal plate, and the usable time of the battery-powered device becomes longer by the reduced contact resistance.

The decrease in the contact resistance of the negative electrode terminal plate 13 was confirmed by actually measuring the contact resistance of the negative electrode terminal plate 13 manufactured through the process of FIG. The characteristic curve indicated by the solid line in FIG. 4 indicates the measured value of the contact resistance of the negative electrode terminal plate 13 described above, and the characteristic curve indicated by the broken line indicates the negative electrode terminal having a nickel plating layer formed on the electrode surface of the conventional battery shown for comparison. This is the contact resistance of the plate. When measuring this contact resistance, a nickel-tin alloy layer 14
The negative electrode terminal plate 13 according to the battery of the present invention having 10 and the negative electrode terminal plate of the conventional battery having a nickel plating layer on the electrode surface were each manufactured by 10 pieces. Each of these 10 samples has 0.5kgf, 1.0kgf, 1.5kf
A load of gf was sequentially applied, and the contact resistance when the load was applied was measured by a four-terminal AC method. FIG. 4 shows the calculated and averaged contact resistance values of ten contact resistance values obtained by measuring each load. In this case, a gold-plated terminal was used as a measuring terminal. As can be seen from the drawing, the contact resistance of the negative electrode terminal plate 13 of the battery according to the present invention is considerably reduced. Further, an alkaline battery having the structure shown in FIG. Was loaded into a battery-powered device, and the usable time of the device was measured. As a result, when the driving duration of the battery-powered device using the conventional alkaline battery is “100”, the battery of the present invention has “1” when the current is 500 mA.
03 ", and when the current is 750 to 1000 mA," 11
0 ". Thus, by using the battery of the present invention,
It has been found that the usable time of the battery-powered device is prolonged by the reduction in the contact resistance of the negative electrode terminal plate 13.

The nickel-tin alloy layer 14 is
Since it has the high-hardness characteristic peculiar to the intermetallic compound of nickel and tin, the surface hardness is higher than that of a single metal plating layer of nickel or tin. Pickers hardness method (Hv10
As measured in g), the surface hardness of the nickel-plated layer was "189", whereas the surface hardness of the nickel-tin alloy layer 14 was as high as "261". Therefore, even when the battery provided with the negative electrode terminal plate 13 is subjected to vibration in a state where the battery is used, the nickel-tin alloy layer 14 of the negative electrode terminal plate 13 is rubbed by the negative electrode terminal of the battery device. It does not fall off, and a situation such as an increase in contact resistance due to oxidation of the dropped fine powder does not occur.

Further, since the negative electrode terminal plate 13 having the nickel-tin alloy layer 14 on the electrode surface has an intermetallic compound formed thereon, it has improved alkali resistance while having tin soluble in an alkaline solution. In addition, the corrosion resistance to salt water is improved. To confirm this, a steel sheet having a nickel-tin alloy layer formed on the surface and a steel sheet for comparison having a tin plated layer formed on the surface were immersed in 12 ml of a 10 moi aqueous potassium hydroxide solution to obtain a solution. The solution was allowed to stand for 14 days in an environment of ° C., and the dissolved amount of tin was measured. As a result, the dissolved amount of tin was 800 ppm in the steel sheet having the tin plating layer formed thereon, whereas it was only 70 ppm in the steel sheet having the nickel-tin alloy layer formed therein. Therefore, the negative electrode terminal plate 13 having the nickel-tin alloy layer 14 can be used without any trouble as a component for an alkaline battery into which an alkaline electrolyte is injected.

In order to confirm the occurrence of corrosion due to salt water, the above two types of steel sheets were subjected to a salt spray test to confirm the state of rust generation. In contrast, no rust and discoloration occurred in the steel sheet on which the nickel-tin alloy layer was formed.

In the above embodiment, the negative electrode terminal plate 13 in the alkaline battery having the battery case 1 integrally provided with the positive electrode terminal 2 has been described as an example of the terminal portion on which the nickel-tin alloy layer 14 is formed. However, it is also possible to adopt a configuration in which a nickel-tin alloy layer is formed on the terminal portion on the positive electrode side. For example, a nickel-tin alloy layer may be formed on the electrode surface outside the positive electrode cap in a battery in which the positive electrode cap is provided separately from the battery case. In the above-described embodiment, the nickel-tin alloy layer 14 is formed only on the outer electrode surface of the negative electrode terminal plate 13. However, depending on the plating process, the nickel-tin alloy layer 14 may be formed on both surfaces of the negative electrode terminal plate 13. The layer 14 may be formed. Furthermore, in the embodiment, the nickel-tin alloy layer 14 is formed by applying tin plating and then tin plating. However, the nickel-tin alloy layer is formed by plating a nickel-tin alloy on a steel plate. 14 may be formed.

[0020]

As described above, according to the battery of the present invention,
Since the nickel-tin alloy layer is formed on at least the outer surface of the negative electrode and / or the positive electrode terminal portion, the contact resistance between the terminal portion and the electrode terminal of the electronic device becomes lower than that of the conventional battery. It becomes smaller as compared with the terminal portion on which the nickel plating layer is formed, so that the usable time of the battery-powered device can be prolonged. In addition, nickel
The tin alloy layer is formed of an intermetallic compound of nickel and tin, and has a high hardness characteristic unique to the compound and a high surface hardness. In addition, the intermetallic compound improves both alkali resistance and corrosion resistance to salt water, so that it can be applied to an alkaline battery into which an alkaline electrolyte is injected without any problem.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a battery according to an embodiment of the present invention.

FIG. 2 is a flowchart showing a manufacturing process of a negative electrode terminal plate in the battery.

FIG. 3 is a vertical sectional view of the negative electrode terminal plate.

FIG. 4 is a characteristic diagram showing actually measured contact resistance values with respect to load in the negative electrode terminal plate.

[Explanation of symbols]

 13 Negative electrode terminal plate (terminal part) 14 Nickel-tin alloy layer

Continued on the front page (72) Inventor Takashi Shimizu 1006 Kazuma Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. Reference) 5H011 AA04 CC06 DD18 EE04 5H022 AA04 AA07 BB22 CC01 EE01 EE03 5H024 DD02 DD11 EE01

Claims (1)

[Claims] 1. A battery characterized in that a nickel-tin alloy layer is formed on at least an outer surface of a terminal portion of a negative electrode and / or a positive electrode.