JP2007172976A - Alkaline storage battery and manufacturing method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent an insulating ring from protruding from between each upper face of electrodes and underside of annular grooves, even if the projecting portion of the annular groove into a packaging can abuts against the insulating ring. <P>SOLUTION: This alkaline storage battery comprises an electrode assembly which is formed by welding an current collector 14 on the top portion of an electrode group, including positive electrodes 11, separators 13, and negative electrodes 12; and a packaging can 16 which contains an alkali electrolyte, and has a annular groove 16a at the upper circumference portion and is sealed with a seal-opening closure at the opening portion. A planar insulating ring 17, having a cut portion, is arranged between the underside of the annular groove 16a and the topside of the current collector 14, both ends of the cut portion 17a approaching each other due to the pressure applied from the ring-like groove 16a. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an alkaline storage battery such as a nickel-cadmium storage battery or a nickel-hydrogen storage battery, and in particular, contains an electrode body in which a current collector is welded to an upper part of an electrode group including a positive electrode, a separator, and a negative electrode, and an alkaline electrolyte. In addition, the present invention relates to an alkaline storage battery in which a sealing body is disposed and sealed in an opening of an outer can in which an annular groove is formed in an upper outer peripheral portion, and a manufacturing method thereof.

  In general, an alkaline storage battery such as a nickel-cadmium storage battery or a nickel-hydrogen storage battery has a separator interposed between a positive electrode and a negative electrode, and these are spirally wound to form an electrode group. While welding an electric body, a negative electrode collector is welded to the edge part of a negative electrode, and an electrode body is formed. Thereafter, the obtained electrode body is inserted into a metal battery case (external can), and the inner bottom portion of the external can and the negative electrode current collector are welded. Next, the upper outer periphery of the outer can is grooved to form an annular groove, and then an alkaline electrolyte is injected into the outer can. Next, after welding the lead portion extending from the positive electrode current collector to the sealing body, the sealing body is arranged via a gasket on the annular groove of the opening of the outer can, and the outer can is sealed by caulking. An alkaline storage battery is manufactured.

In the alkaline storage battery configured as described above, the electrode body moves in the outer can due to impact or vibration, and the positive electrode current collector and the annular groove of the outer can (also serving as the negative electrode terminal) come into contact with each other to cause an internal short circuit. Caused the problem of causing. Therefore, for example, as described in Patent Document 1 (Japanese Patent Laid-Open No. 2001-143684), an annular insulating ring (vibration-proof ring) is disposed between the upper surface of the electrode body and the lower end surface of the annular groove. Therefore, it has been proposed to prevent an internal short circuit between the positive electrode current collector and the annular groove.
JP 2001-143684 A

  By the way, in recent years, there has been an increasing demand for higher capacity and higher density for batteries, and various attempts have been made to effectively utilize the limited space in the battery. The upper surface of the electrode body, the lower surface of the sealing body, In other words, the gap between the upper surface of the electrode body and the annular groove needs to be as small as possible. Therefore, an attempt is made to arrange the above-described annular insulating ring (vibration-proof ring) in a minute gap between the upper surface of the electrode body and the lower end surface of the annular groove and to make the minute gap as small as possible. Became. In this case, when the minute gap between the upper surface of the electrode body and the lower end surface of the annular groove is reduced, a situation occurs in which the protruding portion into the outer can of the annular groove hits the insulating ring when the annular groove is formed. As a result, the insulation ring moves and protrudes from between the upper surface of the electrode body and the lower end surface of the annular groove (refer to part A in FIG. 4).

  In a state where such an insulating ring protrudes from between the upper surface of the electrode body and the lower end surface of the annular groove, when receiving an impact from the outside of the battery, the positive electrode current collector and the outer can come into contact to cause an internal short circuit. The problem that occurred. In this case, by reducing the thickness of the insulating ring, it becomes possible to prevent the protruding portion into the outer can of the annular groove from hitting the insulating ring when the annular groove is formed. If it is too much, a new problem that the insulating property is lowered occurs.

  Therefore, the present invention has been made to solve the above problems, and the gap between the upper surface of the electrode body and the lower end surface of the annular groove is made as small as possible, and an insulating ring is disposed in these gaps. Even if the protrusion into the outer can of the annular groove hits the insulating ring, the insulating ring does not protrude from between the upper surface of the electrode body and the lower end surface of the annular groove, and contact between the current collector and the outer can due to impact is prevented. An object of the present invention is to provide an alkaline storage battery that can be prevented and a method for producing the same.

  The alkaline storage battery of the present invention accommodates an electrode body including an electrode group composed of a positive electrode, a separator, and a negative electrode, and an alkaline electrolyte, and a sealing body is disposed in an opening of an outer can in which an annular groove is formed in an upper outer peripheral portion. Being sealed. And in order to achieve the said objective, the annular | circular shaped insulating ring provided with the cutting part is arrange | positioned between the lower end part of the annular groove formed in the upper outer peripheral part of an exterior can, and the upper surface of an electrode body, and insulation is carried out. The ring is characterized in that both ends of the cutting portion are approached by a pressing force from the annular groove.

  In this way, an annular insulating ring having a cutting portion is arranged between the lower end portion of the annular groove and the upper surface of the electrode body, and both end portions of the cutting portion are approached by the pressing force from the annular groove. When the battery is impacted from the outside, the current collector welded to the upper part of the electrode group and the annular groove formed in the outer can contact with each other to prevent an internal short circuit. Become.

  And when manufacturing the alkaline storage battery as described above, an insulating ring arrangement step of arranging an annular insulating ring having a cut portion formed on the upper surface of the electrode body, and grooving processing on the upper outer peripheral portion of the outer can After forming the annular groove and placing the sealing body on the annular groove, the annular groove forming step of bringing both ends of the cutting portion closer based on the reduced diameter of the insulating ring due to the pressing force from the annular groove, What is necessary is just to provide the sealing process which seals the said sealing body airtightly. As a result, even if the annular groove hits the insulating ring during the formation of the annular groove and a pressing force is applied, the diameter of the insulating ring is reduced by the cut portion, so that both ends of the cut portion of the annular insulating ring approach each other. Will be.

  Below, an embodiment at the time of applying the present invention to a nickel-cadmium storage battery is described based on figures. In addition, FIG. 1 is a figure which shows typically the nickel-cadmium storage battery of one Example of this invention before forming an annular groove in the upper outer peripheral part of an exterior can, FIG. 1 (a) is sectional drawing, FIG. 1B is a top view. FIG. 2 is a view schematically showing a nickel-cadmium storage battery according to an embodiment of the present invention after an annular groove is formed in the upper outer peripheral portion of the outer can, and FIG. FIG. 2B is a top view. Moreover, FIG. 3 is a figure which shows typically the nickel-cadmium storage battery of the comparative example (conventional example) before forming an annular groove in the upper outer periphery of the outer can, and FIG. 3 (a) is a sectional view. FIG. 3B is a top view. FIG. 4 is a diagram schematically showing a nickel-cadmium storage battery of a comparative example (conventional example) after forming an annular groove in the upper outer peripheral portion of the outer can, and FIG. FIG. 4B is a top view.

1. Sintered Nickel Positive Electrode Thickener such as carboxymethyl cellulose and water are kneaded with nickel powder to prepare a slurry, and this slurry is applied to a conductive core made of punching metal and then sintered in a reducing atmosphere. Thus, a nickel sintered substrate was produced. The obtained nickel sintered substrate was immersed in an aqueous nickel nitrate solution having a specific gravity of 1.70 and then dried. Subsequently, it was immersed in an aqueous sodium hydroxide solution having a concentration of 6 mol / l and a temperature of 60 ° C. to perform alkali treatment, and nickel nitrate was chemically changed to nickel hydroxide to form an active material. Thereafter, washing with water and drying were performed. Such an active material filling operation was repeated a predetermined number of times to fill the pores of the nickel sintered substrate with a predetermined amount of an active material mainly composed of nickel hydroxide. After drying, the sintered nickel positive electrode 11 was manufactured by cutting into a predetermined size.

2. Paste type cadmium negative electrode 80% by mass of cadmium oxide powder and 20% by mass of metal cadmium powder were mixed to obtain a mixed active material powder. Thereafter, a solution obtained by adding nylon fiber or the like to a methylcellulose solution as a binder was added to and mixed with the mixed active material powder to prepare a negative electrode active material paste. Next, this negative electrode active material paste was applied to both surfaces of a conductive core made of punching metal, and then dried. Then, it cut | disconnected to the predetermined dimension and produced the paste type cadmium negative electrode 12 in which an active material turns into cadmium oxide.

3. Electrode body Next, the obtained sintered nickel positive electrode 11 and paste-type cadmium negative electrode 12 were wound in a spiral shape with a separator 13 interposed therebetween to form a spiral electrode group. Note that, at the upper end of the spiral electrode group, an end portion of a punching metal which is an electrode plate core of the sintered nickel positive electrode 11 is exposed to form a positive electrode conductive edge 11a. On the other hand, at the lower end of the spiral electrode group, the end portion of the punching metal that is the electrode plate core of the paste type cadmium negative electrode 12 is exposed to form a negative electrode conductive edge 12a.

  Next, the positive electrode current collector 14 is disposed above the spiral electrode group, and a pair of welding electrodes (not shown) are placed at a plurality of locations on the positive electrode current collector 14, and the pair of weldings A welding current was applied between the electrodes to resistance weld the positive electrode current collector 14 and the positive electrode conductive edge 11a. On the other hand, the negative electrode current collector 15 is disposed below the spiral electrode group, and a pair of welding electrodes (not shown) are placed at a plurality of locations on the negative electrode current collector 15 so that the pair of weldings are performed. A welding current was applied between the electrodes, and the negative electrode current collector 15 and the negative electrode conductive edge 12a were resistance-welded. Thus, an electrode body (having a diameter of 30.6 mm and a height of 51 mm) in which the positive electrode current collector 14 was welded to the upper end of the spiral electrode group and the negative electrode current collector 15 was welded to the lower end was produced. .

4). Nickel-cadmium storage battery (1) Example 1
Next, a bottomed cylindrical metal outer can (with an inner diameter of 31 mm) 16 in which nickel was plated on iron was prepared, and the electrode body obtained as described above was accommodated in the outer can 16. Thereafter, the negative electrode current collector 15 and the bottom of the outer can 16 (negative electrode external terminal) were resistance welded. Next, a flat plate-shaped insulating ring 17 provided with a cutting portion 17a was prepared, and this insulating ring 17 was placed on the outer peripheral portion of the positive electrode current collector 14 of the electrode body. The insulating ring 17 is formed of a film such as polypropylene (PP) or polyethylene (PE), and has a thickness of 0.9 mm, an outer diameter of 30.6 mm, an inner diameter of 24.2 mm, and the cutting portion 17a. The width is set to 4.0 mm. Thereafter, the upper outer peripheral side of the outer can 16 was grooved to form an annular groove 16a.

  In this case, an annular groove portion 16a was formed at a position 54 mm from the bottom of the outer can 16 so as to protrude into the can by 1.7 mm from the inner surface of the side wall of the outer can 16. Next, a sealing body (not shown) was prepared, in which a gasket was fitted on the outer periphery, and a valve body consisting of a valve plate and a spring was provided inside. Next, after a lead portion (not shown) extending from the positive electrode current collector 14 is welded to the inner bottom portion of the sealing body, an alkaline electrolyte (lithium hydroxide (LiOH) and sodium hydroxide (NaOH) is placed in the outer can 16. 8N aqueous potassium hydroxide (KOH) solution). Next, after the sealing body is placed in the annular groove 16a formed in the outer can 16, the opening edge of the outer can 16 is crimped inward to seal the battery, whereby the nickel-cadmium storage battery A of Example 1 is used. Was made.

(2) Comparative Example 1
Here, an insulating ring 18 (formed from a film such as polypropylene (PP) or polyethylene (PE) and having a thickness of 0.9 mm, an outer diameter of 30.6 mm, and an inner diameter of 24.2 mm) A nickel-cadmium storage battery X of Comparative Example 1 was produced in the same manner as described above except that (see FIG. 3) was used.

5. Observation of Deformation Number of Insulating Ring Next, when 100 batteries A and X are produced as described above, the insulating ring 17 (18) is observed after grooving of the outer can 16, and the insulating ring 17 is observed. When the number of batteries in which deformation occurred in (18) was obtained, the results shown in Table 1 below were obtained.

  As is clear from Table 1 above, it can be seen that in the battery X, the insulation ring 18 is deformed in 20 (20%) batteries. In this case, when the groove portion 16a is formed by grooving so as to protrude from the inner wall of the outer can 16 into the can, the annular groove portion 16a is pressed against the insulating ring 18 so that the insulating ring 18 is To move. As a result, as shown in FIG. 4, deformation such as undulation occurs in the insulating ring 18, and in the worst case, as shown by part A in FIG. 4, the upper surface of the positive electrode current collector 14 and the bottom of the annular groove 16 a The problem that it protruded from between the end faces occurred.

  On the other hand, in the battery A, it can be seen that the deformation of the insulating ring 17 is zero. This is because the insulating ring 17 used in the battery A is formed with a cut portion 17a having a predetermined width. Therefore, the annular groove portion 16a is formed by grooving so as to protrude from the inner surface of the side wall of the outer can 16 into the can. Even when the annular groove 16a is pressed against the insulating ring 17 when forming the insulating ring 17, the insulating ring 17 moves so as to reduce the diameter, as shown in FIG. Thereby, the problem that the insulating ring 17 protrudes from between the upper surface of the positive electrode collector 14 and the lower end surface of the annular groove 16a does not occur. As a result, even when the battery A receives an impact from the outside, it is possible to prevent a situation in which the positive electrode current collector 14 and the outer can 16 are brought into contact to cause an internal short circuit.

  In the above-described embodiment, the example in which the cut portion 17a having a width of 4.0 mm is formed in the insulating ring 17 is described. However, the cut width of the cut portion 17a is not limited thereto. In this case, when forming the annular groove portion 16a by performing grooving, when the annular groove portion 16a presses against the insulating ring 17 and the insulating ring 17 is reduced in diameter, both ends of the cutting portion 17a are as close as possible, It is desirable to set the width so as not to overlap.

  In the above-described embodiment, an example in which a sintered electrode is used for the positive electrode and a paste electrode is used for the negative electrode has been described. However, a sintered electrode is used for the positive electrode and the negative electrode, or both the positive electrode and the negative electrode are used. Alternatively, a non-sintered electrode such as a paste type may be used. Moreover, in embodiment mentioned above, although the example which applies this invention to a nickel-cadmium storage battery was demonstrated, it is clear that this invention is applicable also to alkaline storage batteries, such as a nickel-hydride storage battery.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows typically the nickel cadmium storage battery of one Example of this invention before forming an annular groove in the upper outer peripheral part of an exterior can, FIG.1 (a) is sectional drawing, FIG.1 (b) Is a top view. It is a figure which shows typically the nickel-cadmium storage battery of one Example of this invention after forming the annular groove in the upper outer peripheral part of an exterior can, FIG.2 (a) is sectional drawing which expands and shows the principal part FIG. 2B is a top view. It is a figure which shows typically the nickel-cadmium storage battery of the comparative example (conventional example) before forming an annular groove in the upper outer peripheral part of an exterior can, FIG.3 (a) is sectional drawing, FIG.3 (b) Is a top view. It is a figure which shows typically the nickel-cadmium storage battery of the comparative example (former example) after forming the annular groove in the upper outer peripheral part of an exterior can, and FIG. 4 (a) is sectional drawing which expands and shows the principal part FIG. 4B is a top view.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 ... Sintered nickel positive electrode, 11a ... Electroconductive edge for positive electrodes, 12 ... Paste type cadmium negative electrode, 12a ... Conductive edge for negative electrodes, 13 ... Separator, 14 ... Positive electrode collector, 15 ... Negative electrode collector, 16 ... outer can, 16a ... annular groove, 17 ... insulating ring, 17a ... cut part, 18 ... insulating ring

Claims (2)

An alkaline storage battery that contains an electrode body including an electrode group composed of a positive electrode, a separator, and a negative electrode, and an alkaline electrolyte, and is sealed with a sealing member disposed in an opening of an outer can in which an annular groove is formed in an upper outer peripheral portion. Because
An annular insulating ring provided with a cutting portion is disposed between the lower end portion of the annular groove formed in the upper outer peripheral portion of the outer can and the upper surface of the electrode body,
2. The alkaline storage battery according to claim 1, wherein both ends of the cutting portion are close to each other by the pressing force from the annular groove. After inserting an electrode body including an electrode group composed of a positive electrode, a separator, and a negative electrode and an alkaline electrolyte into an outer can, and forming an annular groove by grooving the upper outer periphery of the outer can, the outer casing A method for producing an alkaline storage battery in which a sealing body is disposed and sealed in an opening of a can,
An insulating ring arrangement step of arranging an annular insulating ring in which a cut portion is formed on the upper part of the electrode body;
An annular groove forming step of forming an annular groove by grooving the upper outer peripheral portion of the outer can and bringing the both ends of the cutting portion closer based on the reduced diameter of the insulating ring due to the pressing force from the annular groove When,
An alkaline storage battery manufacturing method comprising: a sealing step of sealing the sealing body in an airtight manner after disposing the sealing body on the annular groove.

Images