JPH09330725A - Organic electrolyte battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an organic electrolyte battery in which the temperature rise in over discharge can be suppressed without being accompanied by deterioration of discharge capacity to improve the safety by adapting a lead-like negative electrode current collector as the negative electrode plate of an organic electrolyte battery using a metal single body or alloy as negative electrode. SOLUTION: In this battery, a negative electrode current collector 5 is situated on the outermost circumference of an electrode plate group, and bitten into a negative electrode plate, and an insulating part 13 is provided on its end part. Since the quantity of the negative electrode active material situated just under the current collector 5 is therefore minimized, and the negative electrode active material around the negative electrode current collector 5 quickly reacts, compared with the negative electrode material, in the other part, it is completely consumed only by the reaction with a positive electrode active material present on the inside by one turn of the negative electrode 1. Thus, the electric contact between the current collector 5 and the negative electrode plate 1 is cut in the end of discharge to prevent the precipitation of the negative electrode onto the positive electrode plate opposed to the negative electrode 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an organic electrolyte battery provided with a spiral electrode, and more particularly to a lead-shaped current collector for its negative electrode.

[0002]

2. Description of the Related Art Conventionally, organic electrolyte batteries provided with spiral electrodes have been used mainly for applications requiring a momentary large current such as cameras and strobes due to their excellent discharge characteristics and storage stability. There is.

However, the organic electrolyte battery uses a flammable organic electrolyte as the electrolyte. Therefore, it is necessary to consider the higher level of safety as compared with other aqueous solution batteries.

In particular, if the battery should be over-discharged, the negative electrode active material may be deposited on the positive electrode side, and heat may be generated due to the reaction between the deposited negative electrode active material and the positive electrode active material.

[0005]

In the electrode group formed by spirally forming the positive electrode and the negative electrode, the portion located at the outermost periphery has no active material serving as a reaction partner on the outer side thereof, and therefore, in the final stage of discharge. Has not completely reacted and remains. In an organic electrolyte battery that uses a metal or a metal compound as the negative electrode active material, the negative electrode active material has a higher volumetric energy density than the positive electrode active material, and therefore the negative electrode cannot be used completely on the outermost periphery of the electrode plate group. When positioned, more energy can be charged into the battery as an active material.
Therefore, the outermost periphery of the electrode plate group is usually the negative electrode plate.

However, when the outermost periphery is the negative electrode plate, as described above, there remains a negative electrode that does not completely react with the positive electrode after the end of discharge. That is, when the negative electrode current collector is located at this portion, the negative electrode electrically connected to the current collector exists even at the end of discharge. Therefore, when the battery is over-discharged for some reason, the remaining negative electrode active material is deposited on the positive electrode plate. These precipitates become dendrite-like crystals, which causes a short circuit between the positive electrode and the negative electrode, which causes heat generation and the like. Therefore, it is necessary to collect current from a portion other than the outermost periphery in order to ensure safety during overdischarge.

However, in order to collect current from a portion other than the outermost periphery, the negative electrode current collector is drawn out from between the positive electrode plates to the outside of the electrode plate group. Therefore, if any insulating coating is not provided on the negative electrode current collector, the negative electrode current collector may break through the separator and cause a short circuit.

Conventionally, various resin tapes or glass cloth tapes have generally been used as the insulating coating. However, due to the influence of the tension applied to the electrode plates and the separator when forming the electrode plate group, the separator is liable to break through due to the positive electrode core body and the negative electrode current collector, and this insulating coating collects 0.1 mm or more. If it was not applied to both the front and back of the body, the internal short circuit could not be completely prevented.

The present invention solves such a problem, and provides an organic electrolyte battery capable of suppressing a temperature rise at the time of over-discharging without lowering the discharge capacity.

[0010]

In order to achieve the above object, the battery of the present invention comprises a positive electrode and a negative electrode, which are housed in a battery can and connected to a negative electrode plate. In a battery connected to a battery can or a sealing plate, all or part of the portion of the negative electrode current collector that contacts the negative electrode plate is bitten into the negative electrode plate, and an insulating portion is provided on the end surface of the negative electrode current collector. It is a thing.

The battery to which the present invention is applied is one in which a positive electrode and a negative electrode are spirally arranged in a battery can, and the negative electrode is located at the outermost periphery of the spiral electrode body. Further, a current collector is connected to the outermost peripheral portion of the negative electrode plate, and further connected to a battery can or a sealing plate.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, the negative electrode current collector is located at the outermost periphery of the electrode plate group, and the current collector is bited into the negative electrode plate by 1/3 or more of the thickness of the negative electrode plate. Therefore, compared with the conventional method,
The amount of the negative electrode active material directly below the current collector is small, and the negative electrode active material around the negative electrode current collector is present inside the circumference of the negative electrode because the reaction proceeds faster than the other portions of the negative electrode active material. It is completely consumed only by the reaction with the positive electrode active material. Therefore, by adopting the structure of the present invention, the electrical connection between the current collector and the negative electrode plate is cut off at the end of discharge, and the negative electrode is not deposited on the positive electrode plate even during overdischarge. The biting portion of the negative electrode current collector into this negative electrode plate has the same effect whether it bites the entire contact portion of the current collector with the negative electrode or only the end face of the current collector. Furthermore, by providing an insulating portion on the end surface of the contact portion with the negative electrode plate on the negative electrode current collector, it is possible to more reliably disconnect the electrical connection between the current collector and the negative electrode plate at the end of discharge. Therefore, it is possible to prevent heat generation and the like at the time of over-discharging and to improve safety without deteriorating characteristics such as reduction of discharge capacity.

[0013]

Embodiments of the present invention will be described below with reference to the drawings.

Example 1 As a trial battery, a cylindrical battery having a diameter of 17 mm and a height of 34 mm as shown in FIG. 1 was produced.

First, the negative electrode plate 1 was manufactured by the following procedure. 230 mm × a 0.16 mm thick thin lithium plate
It was cut to a size of 23 mm, and a nickel lead having a thickness of 0.1 mm was used as the negative electrode current collector 5. At this time, the current collector 5 was pressure-bonded to the position shown in FIG. 2A so as to penetrate into the inside of 0.06 mm from the lithium surface 1 as shown in FIG. Further, a 0.05 mm-thick polypropylene adhesive tape 13 was attached onto the negative electrode current collector 5.

Next, the positive electrode plate 2 was produced by the following procedure. Electrolytic manganese dioxide was used as the positive electrode active material, and this was kneaded with carbon, polytetrafluoroethylene, and ion-exchanged water. The mixing ratio of manganese dioxide, carbon, and polytetrafluoroethylene was 100: 6: 4. Then, a core material (not shown) made of stainless expanded metal was filled to a thickness of 0.45 mm. This is 23
The positive electrode current collector 6 was resistance-welded by cutting into a size of 0 mm × 26 mm, and a glass cloth tape was attached as an insulating material on the positive electrode current collector, and dried at 250 ° C. for 4 hours.

The positive electrode plate 2 and the negative electrode plate 1 were spirally wound with a separator 3 of a polypropylene microporous film interposed therebetween to form an electrode plate group. At this time, the position of the negative electrode current collector is shown in FIG.
It is located at the outermost periphery of the electrode plate group as shown in (b).

The electrode plate group was housed in a battery can, and the negative electrode current collector was welded to the outer can 4 and the positive electrode current collector was welded to the sealing plate 8, and then an electrolytic solution was injected into the battery can. As the electrolyte, a 1: 1 mixed solution of propylene carbonate and dimethoxyethane was used as a solvent, and a 0.5 mol / l solution of lithium trifluoromethanesulfonate was used as a solute. Further, this was sealed by caulking to obtain a battery of the present invention.

(Example 2) In the same manner as (Example 2), a cylindrical battery having a diameter of 17 mm and a height of 34 mm was produced. The configuration was the same except for the negative electrode current collector portion, and as the negative electrode current collector, as shown in FIG. 4, a structure having a protrusion 5a having a substantially U-shaped cross section was used. The height of the current collector protrusion 5a is 0.0
6 mm.

(Example 3) In the same manner as (Example 3), a cylindrical battery having a diameter of 17 mm and a height of 34 mm was produced. The configuration is the same except for the negative electrode current collector portion, and as a negative electrode current collector, as shown in FIG. 5, it has a protrusion 5a having a substantially U-shaped cross section, and an insulating film 11 is formed on the outer peripheral surface of the protrusion. The structure having the structure formed was used. Silicon rubber was used for the insulator 11 on the outer periphery of the current collector.

(Comparative Example 1) As Comparative Example 1, the diameter is 1
A cylindrical battery having a size of 7 mm and a height of 34 mm was manufactured. The structure was the same except for the negative electrode current collector portion, and as the negative electrode current collector, as shown in FIG. 6, the current collector 5 was simply lightly crimped and placed.

(Comparative Example 2) As a comparative example, a battery of the same size as that of the example was manufactured and compared.

First, the negative electrode plate 1 and the positive electrode plate 2 were prepared in the same manner as in the example and dried. However, in order to take out the position of the negative electrode current collector from the inside of the electrode plate group, the negative electrode current collector was pressure-bonded to a position inward from the end of the negative electrode plate as shown in FIG. Further, as shown in FIG. 8, a glass cloth tape having a thickness of 0.1 mm was attached on the negative electrode current collector to prevent an internal short circuit. Therefore, when an electrode plate having the same thickness as that of the embodiment is used, the electrode plate group becomes too thick to be inserted into the battery can. Therefore, the thickness of the positive electrode plate is originally 0.45 mm. 0.41
The thickness of the negative electrode plate, which was made thin to 0.1 mm, was 0.16 m.
m.

The positive electrode plate and the negative electrode plate are spirally wound with a polypropylene microporous film separator interposed therebetween,
It was a plate group. At this time, the position of the negative electrode current collector is positioned inside the outermost circumference of the electrode plate group as shown in FIG. 7B.

This electrode plate group was housed in a battery can, and a comparative battery was prepared by the same trial production method as in the example.

The discharge capacities of these batteries were compared. The discharge current conditions were 0.9 A, 3 seconds on, 27 seconds off alternating discharge, and the discharge temperature was 20 ° C. The discharge result under this discharge condition is shown in FIG. The discharge capacities of all Examples are larger than those of Comparative Example 2.

Further, a battery that has been discharged under the above conditions is used, and this battery is connected in series to an undischarged battery of the same specification,
An over-discharge test was conducted. Table 1 shows the maximum temperature and appearance change at this time.

[0028]

[Table 1]

From Table 1, the maximum temperature during the test is lower in Example as compared with Comparative Example 1, and the temperature rise during overdischarge is improved. In addition, in both the examples and the comparative examples, there is no appearance change such as the operation of the explosion-proof valve, and the same safety is ensured.

[0030]

EFFECTS OF THE INVENTION In an organic electrolyte battery using a metal alone or an alloy for the negative electrode, by adopting the negative electrode current collector structure of the present invention, it is possible to suppress the temperature rise at the time of overdischarge without deterioration of the discharge capacity. , Can improve safety.

[Brief description of drawings]

FIG. 1 is a view showing a cross section of a battery.

FIG. 2A is a side view of the negative electrode plate of the present invention. FIG. 2B is a partial sectional view of an electrode plate group using the negative electrode plate of the present invention.

FIG. 3 is a side sectional view of the negative electrode plate of the present invention.

FIG. 4 is a side sectional view of the negative electrode plate of the present invention.

FIG. 5 is a side sectional view of the negative electrode plate of the present invention.

FIG. 6 is a side sectional view of a negative electrode plate for comparison.

FIG. 7A is a side view of a comparative negative electrode plate. FIG. 7B is a partial cross-sectional view of an electrode plate group using the comparative negative electrode plate.

FIG. 8 is a side sectional view of a negative electrode plate for comparison.

FIG. 9 is a diagram showing discharge characteristics of a battery.

[Explanation of symbols]

 1 Negative Electrode Plate 2 Positive Electrode Plate 3 Separator 4 Exterior Can 5 Negative Current Collector 6 Positive Electrode Current Collector 7 Gasket 8 Sealing Plate 9 Upper Insulation Plate 10 Lower Insulation Plate 11 Current Collector Insulation Film 12 Electrode Plate Group 13 Negative Current Collector Insulation Polypropylene tape 14 Negative electrode current collector insulating glass cloth tape

Claims (5)

[Claims] 1. An organic electrolyte battery comprising a negative electrode plate made of an alkali metal such as lithium or an alloy thereof and a negative electrode plate provided with a lead-shaped negative electrode current collector. 2. The organic electrolyte battery according to claim 1, wherein the negative electrode current collector is located at the outermost periphery of the electrode plate group. 3. The negative electrode plate according to claim 1, wherein all or part of a portion of the negative electrode current collector that comes into contact with the negative electrode plate is cut into the negative electrode plate.
The organic electrolyte battery described. 4. The organic electrolyte battery according to claim 3, wherein the biting portion of the negative electrode current collector is 1/3 or more of the thickness of the negative electrode plate. 5. The organic electrolyte battery according to claim 3, wherein an insulating portion is provided on the end surface of the negative electrode current collector.