JPH09190836A - Battery having wound electrode body - Google Patents

Abstract

(57) Abstract: In a battery having a wound electrode body, the capacity is increased, the productivity of the negative electrode is improved, and the cost is reduced.
And prevent scratches on the inner wall of the battery can. In a battery manufactured by inserting an electrode body having a wound structure in which a positive electrode and a negative electrode are wound with a separator interposed between them into a battery can, a thin metal substrate is used as a base of the negative electrode, and one surface of the metal substrate or the metal is used. A negative electrode is formed by forming an active material layer only on one side and in the holes of the substrate, and the negative electrode is arranged on both sides of the positive electrode so that the active material layers face each other via a separator, or is wound, or a metal substrate. An active material layer is formed on both surfaces of the metal substrate, but on one or both of the innermost portion and the outermost portion of the wound electrode body, one side of the metal substrate or a hole of the metal substrate is formed. The active material layer is provided only on the inside and one side, and the negative electrode is arranged so that the active material layer faces the positive electrode via the separator and is wound, to obtain an electrode body having a wound structure.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a battery having a wound structure electrode body represented by an alkaline secondary battery such as a nickel-hydrogen storage alloy battery or a nickel-cadmium battery, and more specifically, to the electrode body. The present invention relates to a battery that has achieved an increase in capacity, an improvement in reliability, an improvement in productivity, a reduction in cost, etc. by improving the winding structure of.

[0002]

2. Description of the Related Art As shown in FIG. 12, an electrode body having a wound structure conventionally used in nickel-hydrogen storage alloy batteries, nickel-cadmium batteries, and the like is composed of one positive electrode 1 and one negative electrode 2. Are spirally wound through the separator 3. That is, both the positive electrode 1 and the negative electrode 2 were formed to have a constant thickness, and the wound electrode body 4 as shown in FIG. 12 was produced.

In an alkaline secondary battery such as a nickel-hydrogen storage alloy battery or a nickel-cadmium battery, an important factor for maintaining normal battery characteristics is [electric capacity of negative electrode] / [capacity of positive electrode]. It is necessary to maintain the ratio of [electric capacity] to 1.0 or more, preferably 1.2 or more, but this is not the ratio of the total amount in the battery but the opposition of the negative electrode and the positive electrode of the wound electrode body. It is necessary that this relationship be maintained at all times.

[0004] Therefore, in a conventional wound structure electrode body,
The battery is designed based on the ratio of [capacity of the negative electrode] / [electric capacity of the positive electrode] in a portion where the positive electrode faces both surfaces of the negative electrode (that is, the second round of the negative electrode). The innermost periphery and the outermost periphery of the negative electrode had an unnecessarily large electric capacity.

[0005]

As described above, in the conventional wound electrode body, the innermost and outermost peripheral portions of the negative electrode are:
Although the active material layer is formed on both sides of the substrate even though only one side faces the positive electrode, the active material layer on one side is not effectively used, and as a result, the internal volume of the battery is sufficient. There was a problem that it was not used.

In a small-sized battery, the outermost portion of the wound electrode body is usually made a negative electrode, and the outermost portion of the negative electrode is brought into contact with the inner wall of the battery can to achieve electrical conduction. . Therefore, the inner wall of the battery can may be scratched (scratched) by the unevenness of the active material layer, and the scratches may cause a fatal defect that an alkaline battery causes electrolyte leakage.

Further, in the conventional negative electrode, a nickel sintered plate obtained by applying a paste containing nickel powder to a nickel punching metal or the like and sintering it is used as a substrate or urethane in order to react from both sides. A porous substrate such as foam metal or fibrous metal produced by firing nickel-plated foam or non-woven fabric was used. Therefore, the cost of the manufacturing equipment for the electrode body itself and its substrate is increased, and a great deal of labor is required to produce a stable and uniform product.

The present invention solves these problems by increasing the capacity by effectively utilizing the internal volume of the battery, improving the productivity of the negative electrode, and reducing the cost, and further, the inner wall of the battery can. The purpose is to prevent scratches and improve reliability.

[0009]

In order to achieve the above-mentioned object, the present invention uses a thin metal plate, a punching metal plate, or the like as a metal substrate which is a base of a negative electrode, and is provided on only one side of the metal substrate or on the metal substrate. A wound structure is formed by forming an active material layer only in one side of the metal substrate and in the formed holes, and arranging the negative electrode on both sides of the positive electrode so that the active material layers face each other via the separator, and winding. That is the electrode body. By doing so, the negative electrode has a structure in which the two sheets are in contact with each other on the surface of the metal substrate except for the substantially innermost peripheral portion and the substantially outermost peripheral portion.

In the present invention, the innermost peripheral portion or the outermost peripheral portion is not formed, but the innermost peripheral portion or the outermost peripheral portion is used. However, this may vary depending on a method of winding the electrode body or a winding machine. It is theoretically preferable that the innermost peripheral portion or the outermost peripheral portion is theoretically true, but there is a slight deviation so that the innermost peripheral portion or the outermost peripheral portion is formed. However, it is practically not a problem.

Further, according to the present invention, the active material layers are formed on both surfaces of the metal substrate which is the substrate of the negative electrode, and it corresponds to either the innermost peripheral portion or the outermost peripheral portion of the electrode body having the winding structure. The active material layer is formed only on one side of the metal substrate or in the holes provided in the metal substrate and only on one side of the metal substrate in the portion corresponding to the innermost portion and the outermost portion. Alternatively, the active material layer is present only on one side of the metal substrate or only on one side of the metal substrate and in the holes provided in the metal substrate by removing after formation.
By arranging and winding the negative electrode so that the active material layer faces the positive electrode via the separator, an electrode body having a wound structure was obtained.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In order to keep the ratio of [electric capacity of the negative electrode] / [electric capacity of the positive electrode] constant in any part of the battery, at least the inside of the negative electrode with respect to the part of the negative electrode facing the positive electrode. It is necessary that the amount of the active material in the peripheral portion is equal to the amount of the active material in the outer peripheral portion, and more preferably, the amount of the active material in the inner peripheral portion is preferably larger than the amount of the active material in the outer peripheral portion, The ratio is preferably from 1.0 to 1.6, particularly preferably from 1.2 to 1.6. This can be controlled by the thickness of the active material layer, if the composition is kept constant. In the present invention, the active material layer is not limited to a case where the active material layer is composed of only the active material, but may also include a case where a binder or the like is contained in addition to the active material.

By setting the winding structure of the negative electrode and the electrode body as described above, the metal substrate surface of the negative electrode is exposed at the substantially outermost peripheral portion of the electrode body. Then, by bringing the metal substrate into contact with the inner wall of the battery can, for example, scratching the inner wall of the battery can with a hard powder such as a hydrogen storage alloy,
It is possible to prevent the inner wall of the battery can from being scratched by a hard substrate formed by a plating method such as foam metal.

What is more important than anything else is that the above structure eliminates the excess waste of the substantially innermost peripheral portion and the substantially outermost peripheral portion of the negative electrode, and further, as a substrate, a thin metal substrate, For example, by using a metal plate having a thickness of 10 μm to 50 μm or a punching metal plate having a thickness of 40 μm to 70 μm, it has become possible to achieve a capacity increase of about 30%.

In the present invention, the ratio of [electric capacity of the negative electrode] / [electric capacity of the positive electrode] required for the battery characteristics of the battery having the wound electrode body is determined not by the total amount in the battery but by each facing portion. Eliminating the excess that does not contribute to the reaction by setting the value to a predetermined value or more leads to the above-described capacity increase.

[0016]

EXAMPLES Next, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to only these examples. Note that, in the following examples and the like,% indicating the concentration is% by weight.

Example 1 Binder solution 28 in which polyvinylidene fluoride was dissolved in N-methyl-pyrrolidone at a concentration of 12% with respect to 100 parts by weight of hydrogen storage alloy powder mainly composed of MmNi ₅
Add parts by weight, mix, and stir thoroughly to prepare a uniform paste. This paste has a thickness of 20 μm as a metal substrate.
m nickel plate was applied by a squeegee method so that the total thickness would be 500 μm. After drying this on a hot plate, it was compressed by a roll press to produce a negative electrode sheet having a total thickness of 200 μm. Then, this negative electrode sheet having a total thickness of 200 μm was cut into a size of 35 mm × 38 mm to obtain a negative electrode sheet A. Note that the above Mm is misch metal.

Separately from the above, a negative electrode sheet having a total thickness of 145 μm was prepared in the same manner as above except that the coating thickness was adjusted. Then, the negative electrode sheet having a total thickness of 145 μm is
This was cut into a size of 5 mm × 55.5 mm, and this was used as a negative electrode sheet B.

For the positive electrode, a nickel electrode having a thickness of 660 μm and a size of 35 mm × 46 mm was prepared by filling a foamed nickel with a paste containing nickel hydroxide as an active material and cutting the paste into a predetermined size. Was used.
Then, one end of the nickel ribbon was spot-welded to the compressed portion of the foamed nickel as the substrate at the end of the positive electrode to form a current collector (tab) of the positive electrode.

The separator has a hydrophilically treated thickness of 0.1.
An electrode having a winding structure shown in FIG. 1 in which a polypropylene nonwoven fabric having a size of 5 mm and a size of 102 mm × 38 mm is used, this separator is interposed between the negative electrode and the positive electrode, and the positive electrode and the negative electrode are spirally wound through the separator. The body was made.

The electrode body shown in FIG. 1 will now be described. The negative electrode 2 is opposed to both surfaces of the positive electrode 1 with the separator 3 interposed therebetween. The two are in direct contact with each other. As shown in FIG. 2 in detail, the negative electrode 2 is formed by forming an active material layer 2b on a metal substrate (a nickel plate is used in this embodiment) 2a as a substrate. 2a are in contact with each other. In the production of the electrode body having the wound structure, the separator 3 has a substantially central portion as a winding central portion, which is shown in a substantially central portion in FIG.
20 is a current collector (tab) of the positive electrode 1,
Is provided at the outermost peripheral portion of the. As will be described later again, this current collecting unit 20 collapses the voids of the foamed nickel, which is the substrate of the positive electrode 1, so that the paste containing nickel hydroxide does not enter the voids, and only the metal body is provided. It is constructed by welding one end of a nickel ribbon as a lead body. The configuration of the current collector 20 is the same in FIGS. 5, 7, 9, 11 and the like.

At the inner peripheral portion of the negative electrode 2, first, the negative electrode sheet A is used, and the negative electrode sheet B is added from the middle (the negative electrode sheet B is added to the inner peripheral side of the negative electrode sheet A). When 1 is on the second lap, the metal substrates 2a of the negative electrode 2 facing both surfaces of the positive electrode 1 via the separator 3 are in direct contact with each other, and almost the outermost peripheral part of the negative electrode 2 is the negative electrode sheet B only. It is composed of.

Although not shown in detail, the negative electrode 2
The metal substrate is exposed on the outer surface of the outermost part of the
The metal substrate contacts the inner wall of the battery can 5, whereby the battery can 5 acts as a negative electrode terminal. That is, the metal substrate in the negative electrode 2 also serves as the negative electrode current collector. In FIG. 1, only the inner peripheral surface of the battery can 5 is shown by a thin line. Further, this FIG. 1 is a schematic illustration, and in this FIG. 1, it is shown that there is a large gap between the electrode body 4 and the battery can 5, but this is actually the thickness. This is because the thin members (the positive electrode 1 is 660 μm, the negative electrode 2 is 200 μm and 145 μm, and the separator 3 is 0.15 mm) are shown with a certain thickness, and in reality, a large void as shown is not possible. . These are the same in FIGS. 5, 7, 9, 11, 12 and the like.

An aqueous solution of 30% potassium hydroxide was used as the electrolytic solution, the electrode body having the above-mentioned winding structure was inserted into a battery can, and 0.85 ml of the above electrolytic solution was injected. A nickel-hydrogen storage alloy-based alkaline secondary battery was produced. The structure of this battery is schematically shown in FIG.

The battery shown in FIG. 3 will now be described. 1 is a positive electrode, 2 is a negative electrode, 3 is a separator, 4 is an electrode body having a winding structure, 5 is a battery can, 6 is an annular gasket, and 7 is a battery lid. , 8 is a terminal plate, 9 is a sealing plate, 10 is a metal spring, 11
Is a valve body, 12 is a positive electrode lead body, 13 is an insulator, and 14 is an insulator.

The positive electrode 1 is composed of the above-mentioned paste-type nickel electrode, and the negative electrode 2 is prepared as described above.
Although the negative electrode sheets A and B are used in the above-described mode, the details thereof are not shown in FIG. 3 and are shown as a single sheet. The active material of the negative electrode 2 is made of a hydrogen storage alloy. The separator 3 is made of the polypropylene nonwoven fabric hydrophilically treated as described above, and the positive electrode 1 and the negative electrode 2 are the separator 3
Through so as to be in the specific mode,
A spirally wound electrode body 4 is inserted into the battery can 5 as an electrode body 4, and an insulator 14 is arranged on the upper portion thereof.

The annular gasket 6 is made of nylon 66, the battery lid 7 is composed of the terminal plate 8 and the sealing plate 9, and the opening of the battery can 5 is sealed by the battery lid 7 and the annular gasket 6. There is.

That is, the electrode body 4 having a winding structure in the battery can 5.
After inserting the insulator 14 and the like, an annular groove 5a whose bottom protrudes inward is formed in the vicinity of the open end of the battery can 5,
The annular gasket 6 and the battery lid 7 are arranged in the opening of the battery can 5 by supporting the lower part of the annular gasket 6 with the inner peripheral side protruding portion of the groove 5a. The opening of the battery can 5 is sealed with a battery lid 7 and an annular gasket 6.

The terminal plate 8 is provided with a gas discharge hole 8a, the sealing plate 9 is provided with a gas detection hole 9a, and the terminal plate 8 is provided.
A metal spring 10 and a valve body 11 are arranged between the metal plate 10 and the sealing plate 9. Then, the outer peripheral portion of the sealing plate 9 is bent to sandwich the outer peripheral portion of the terminal plate 8, thereby fixing the terminal plate 8 and the sealing plate 9.

This battery has a metal spring 1 under normal circumstances.
Since the valve body 11 closes the gas detection hole 9a by the pressing force of 0, the inside of the battery is kept in a sealed state, but gas is generated inside the battery and the pressure inside the battery rises abnormally. , The metal spring 10 contracts to form a gap between the valve body 11 and the gas detection hole 9a, and gas inside the battery passes through the gas detection hole 9a and the gas discharge hole 8a and is discharged to the outside of the battery. It is configured to prevent battery rupture.

The positive electrode lead body 12 is made of a nickel ribbon, and one end portion of the positive electrode lead body 12 is spot-welded to the metal plate-like portion of the substrate in the outermost peripheral portion of the positive electrode 2, and the end portion 2 shown in FIG.
A current collector (tab) as shown by 0 is formed, the other end is spot-welded to the lower end of the sealing plate 9, and the terminal plate 8 functions as a positive electrode terminal by contact with the sealing plate 9.

As described above, the metal substrate is exposed on the outer surface side of the outermost peripheral portion of the negative electrode 2, and the metal substrate contacts the inner wall of the battery can 5, whereby the battery can 5 has a negative electrode terminal. Acts as. It should be noted that FIG. 3 is also schematically shown, and details of the positive electrode 1, the negative electrode 2, the separator 3, etc. are not shown, and the positions thereof are slightly different from those of FIG. 1, and the positive electrode lead body 12 is also cut. The drawings are shown as if they are arranged on a surface, and the cross section of the negative electrode 2 is also shown in a mode different from that shown in FIGS.

The battery of Example 1 is regulated by the positive electrode, and the theoretical electric capacity of filling the positive electrode is 600 mAh.
FIG. 13 shows the discharge characteristics when discharged at 0.1 ° C. and 0.1 A.
Shown in The theoretical filling capacity of the negative electrode is 977 mAh.
The ratio of [electric capacity of negative electrode] / [electric capacity of positive electrode] in this battery is 1.63.

Example 2 As a negative electrode, a negative electrode prepared by forming a portion where an active material layer was not formed as shown in FIG. 4 was used. The negative electrode shown in FIG. 4 will be described in detail. FIG. 4 (a) is a side view of the negative electrode on the side where the active material layer is formed, and FIG. 4 (b) is taken along line XX of (a) above. It is a sectional view. FIG.
In (a), in order to make it easy to see the portion where the active material layer 2b is formed, the active material layer 2b is hatched in a cross shape.

A nickel plate having a thickness of 20 μm is used as a metal substrate 2a which is a base body of the negative electrode, an active material layer 2b is formed on one surface of the nickel plate at a thickness of 180 μm, and the total thickness of the negative electrode 2 is 200 μm. However, there is a portion where the active material layer is not formed in a part of the negative electrode 2, and specifically, the negative electrode 2
Has a total length of 100 mm, but 38 from one end
Although the active material layer 2b is formed up to the position of mm, the active material layer is not formed over a width of 6.5 mm from that, and the active material layer 2b is formed for the remaining 55.5 mm width. There is. The width of the negative electrode 2 is 35 mm. Note that this FIG. 4 is also schematically shown, and the thickness of the metal substrate 2a and the active material layer 2b are shown to be larger than the length of the negative electrode 2, and the active material layer of the negative electrode 2 is also shown. The positions and widths of the portions that are not formed are not necessarily shown according to the dimensions.

An electrode having the winding structure shown in FIG. 5 is formed by spirally winding the negative electrode 2 and the positive electrode 1 with the separator 3 in between, centering on the portion of the negative electrode 2 where the active material layer is not formed. The body was made. However, in the negative electrode 2, the active material layer 2 b faces the positive electrode 1 with the separator 3 interposed therebetween, and the metal substrate 2
It was arranged so that a was in contact with each other. Also in the electrode body having the winding structure shown in FIG. 5, the negative electrodes 2 face each other on both sides of the positive electrode 1 with the separator 3 interposed therebetween. In direct contact. The details are similar to those described with reference to FIG. 2, and the metal substrates 2a of the negative electrode 2 are in contact with each other. The thickness of the innermost peripheral portion and the outermost peripheral portion of the negative electrode 2 is half the thickness of the other portions, and although not shown in detail, the outermost surface of the negative electrode 2 is on the outermost side. The metal substrate is exposed, and the metal substrate is in contact with the inner wall of the battery can 5.

The positive electrode 1 is composed of the same paste type nickel electrode as in the first embodiment, and the positive electrode 1 has a thickness of 660 μm.
m and its size is 35 mm x 46 mm. The separator 3 has the same thickness of 0.15 as in the first embodiment.
mm non-woven polypropylene fabric, size 102
mm × 38 mm.

Then, using the spirally wound electrode body produced by using the positive electrode 1, the negative electrode 2 and the separator 3, the same procedure as in Example 1 is carried out, and then, in the same manner as in Example 1, a nickel-hydrogen storage alloy type alkali electrolyte is used. A secondary battery was produced.

This battery is regulated by the positive electrode, and the theoretical electric capacity of filling the positive electrode is 600 mAh.
FIG. 13 shows the discharge characteristics when discharged by A discharge. The filling theoretical electric capacity of the negative electrode was 977 mAh, and the ratio of [negative electrode electric capacity] / [positive electrode electric capacity] in this battery was 1.63.

Example 3 A negative electrode having the structure shown in FIG. 6 was prepared. This figure 6
The negative electrode 2 shown in FIG. 4 is the same as the negative electrode 2 shown in FIG.
It corresponds to the one without the part without b. Therefore,
The negative electrode 2 shown in FIG. 6 will be described in detail.
6A is a side view of the side of the negative electrode 2 on which the active material layer 2b is formed, and FIG. 6B is a sectional view taken along line WW of FIG. 6A. In FIG. 6A, in order to make it easy to understand the portion where the active material layer 2b is formed, the active material layer 2b is hatched in a cross shape.

A nickel plate having a thickness of 20 μm is used as a metal substrate 2a serving as a base of the negative electrode 2, and an active material layer 2b is formed on one surface thereof to have a thickness of 180 μm, and the total thickness of the negative electrode 2 is 200 μm. . And the total length of this negative electrode 2 is 1
The width is 00 mm and the width is 35 mm. It is to be noted that FIG. 6 is also schematically shown, and the thickness of the metal substrate 2a and the thickness of the active material layer 2b are shown larger than the length of the negative electrode 2.

The negative electrode 2, the positive electrode 1, and the separator 3 were interposed and spirally wound to produce an electrode body having a wound structure shown in FIG. However, although it is not clear on the drawing,
As compared with the electrode body having the wound structure of Example 2, the diameter of the wound core is reduced by 0.2 mm which is a thickness corresponding to the coating thickness of the negative electrode paste, and the active material layer 2b of the negative electrode 2 has the separator 3 formed therein. It was arranged so as to face the positive electrode 1 with the metal substrates 2a in contact with each other. Also in the electrode body having the winding structure shown in FIG. 7, the negative electrode 2 is opposed to both surfaces of the positive electrode 1 with the separator 3 interposed therebetween, but is almost 2 except the outermost peripheral portion.
After the circumference, the negative electrodes 2 are in direct contact with each other. The details are similar to those described with reference to FIG. 2, and the metal substrates 2a of the negative electrode 2 are in contact with each other. The thickness of the innermost peripheral portion and the outermost peripheral portion of the negative electrode 2 is half the thickness of the other portions, and although not shown in detail, the outermost surface of the negative electrode 2 is on the outermost side. The metal substrate is exposed, and the metal substrate is in contact with the inner wall of the battery can 5.

The positive electrode 1 is composed of the same paste type nickel electrode as in the first embodiment, and the positive electrode 1 has a thickness of 660 μm.
m and its size is 35 mm x 46 mm. The separator 3 has the same thickness of 0.15 as in the first embodiment.
mm non-woven polypropylene fabric, size 102
mm × 38 mm.

Then, using the electrode body having the wound structure produced by using the positive electrode 1, the negative electrode 2 and the separator 3, the same procedure as in Example 1 is carried out. A secondary battery was produced.

This battery is regulated by the positive electrode and the theoretical electric capacity of filling the positive electrode is 600 mAh.
FIG. 13 shows the discharge characteristics when discharged by A discharge. The theoretical filling capacity of the negative electrode is 1041 mAh,
The ratio of [electrical capacity of negative electrode] / [electrical capacity of positive electrode] of the facing portion of the positive electrode and the negative electrode in this battery was 1.63. In addition, in FIG. 13, the same curves are used for Example 2 and Example 3.
The discharge characteristics of Example 3 have almost no difference from the discharge characteristics of Example 2, and the difference between the two cannot be clearly shown in FIG. Is represented by a single curve.

Example 4 As a negative electrode, a negative electrode prepared by forming a portion not provided with an active material layer as shown in FIG. 8 was used. The negative electrode shown in FIG. 8 will be described in detail. FIG. 8A is one side view of the negative electrode, and FIG. 8B is the other side view of the negative electrode.
(C) is a sectional view taken along the line VV in (a). In FIGS. 8A and 8B, the active material layers 2b and 2c are hatched in a cross shape for easy understanding of the portions where the active material layers 2b and 2c are provided.

The metal substrate 2a of the negative electrode 2 has a thickness of 20 μm.
m nickel plate is used, the active material layer 2b is formed to a thickness of 200 μm on one surface of the metal substrate 2a, and the active material layer 2c is formed to a thickness of 145 μm on the other surface of the metal substrate 2a. The total thickness of 2 is 365 μm. However, negative electrode 2
There is a portion where the active material layer is formed only on one side of the metal substrate, and specifically, the total length of the negative electrode 2 is 67 m.
However, the active material layer is not formed on one surface of the metal substrate 2a from the one end E to the other end F of the metal substrate 2a up to 26 mm, and thereafter, the other active material layer is not formed. The active material layer 2b is continuously formed up to the end F, and the metal substrate 2
On the other surface of a, the active material layer 2c is formed from one end E to the other end F at a position of 63.2 mm, and the remaining 3.8 mm is not formed with the active material layer. . The width of the negative electrode 2 is 35 mm.

The negative electrode 2 and the positive electrode 1 were spirally wound with the separator 3 interposed therebetween to produce an electrode body having a wound structure shown in FIG. However, in producing the electrode body having the above-mentioned winding structure, the separator 3 is folded back at the central portion thereof, arranged so as to cover both surfaces of the negative electrode 2, and the end portion F (see FIG. 8) side is the center side of the spiral. Thus, it was wound in a spiral shape. Also in this case, at least the active material layer 2b or 2c of the negative electrode 2 faces the positive electrode 1 with the separator 3 interposed therebetween. 8 and 9 are also shown schematically, and for example, the thickness of the metal substrate 2a and the thicknesses of the active material layers 2b and 2c are shown to be larger than the length of the negative electrode 2, or The positions and widths of the portions of the negative electrode 2 where the active material layer is not formed are not necessarily shown according to the dimensions. Further, regarding the electrode body having the winding structure shown in FIG. 9, a portion not shown in FIG. 9 will be described.
Only the active material layer 2b (see FIG. 8) faces the positive electrode 1 through the separator 3 at almost the innermost periphery of the negative electrode 2, and only the active material layer 2c (see FIG. 8) at the substantially outermost periphery of the negative electrode 2. The positive electrode 1 is opposed to the positive electrode 1 via the separator 3, and the active material layers 2 b and 2 c are opposed to the positive electrode 1 via the separator 3 in portions other than the substantially innermost peripheral portion and the substantially outermost peripheral portion. Similarly, FIG.
Although not shown in FIG. 3, a metal substrate is exposed on the outer surface side of the outermost portion of the negative electrode 2, and the metal substrate is used for the battery can 5.
Is in contact with the inner wall.

The positive electrode 1 is made of the same paste-type nickel electrode as in the first embodiment, and the positive electrode 1 has a thickness of 660 μm.
m and its size is 35 mm x 46 mm. The separator 3 has the same thickness of 0.15 as in the first embodiment.
mm non-woven polypropylene fabric, size 102
mm × 38 mm.

Then, using the wound electrode body produced by using the positive electrode 1, the negative electrode 2 and the separator 3, the same procedure as in Example 1 is carried out, and then, in the same manner as in Example 1, a nickel-hydrogen storage alloy type alkali electrolyte is used. A secondary battery was produced.

This battery is regulated by the positive electrode and the theoretical electric capacity of filling the positive electrode is 600 mAh.
FIG. 13 shows the discharge characteristics when discharged by A discharge. The filling theoretical electric capacity of the negative electrode was 977 mAh, and the ratio of [negative electrode electric capacity] / [positive electrode electric capacity] in this battery was 1.63.

Example 5 A negative electrode having the structure shown in FIG. 10 was prepared. The negative electrode 2 shown in FIG. 10 corresponds to the negative electrode 2 shown in FIG. 8 in which a punching metal plate is used as the metal substrate 2a instead of the metal plate. Therefore, the negative electrode 2 shown in FIG. 10 will be described in detail. (A) of FIG. 10 is one side view of the negative electrode 2, and (b) of FIG. 10 is the other side view of the negative electrode 2. (C) is a sectional view taken along line U-U in (a) above. In addition, (a) and (b) of FIG.
In FIG. 4, in order to make it easy to see the portions where the active material layers 2b and 2c are provided, the active material layers 2b and 2c are hatched in a cross shape.

The above-mentioned negative electrode has a binder solution 2 in which polyethylene oxide is dissolved in water at a concentration of 8.0% with respect to 100 parts by weight of a hydrogen storage alloy powder mainly composed of MmNi _5.
3 parts by weight were added and mixed, and stirred sufficiently to prepare a uniform paste, which was filled and applied on a punching metal plate having a thickness of 50 μm, dried, and then compressed by a roll press.

The metal substrate 2a of the negative electrode 2 has a thickness of 50 μm.
A so-called punched metal plate obtained by punching an iron plate having a thickness of m and then nickel plating is used. An active material layer 2b having a thickness of 200 μm is formed on one surface of the metal substrate 2a and an active material layer 2b is formed on the other surface. The material layer 2c has a thickness of 145 μm
And the negative electrode 2 has a total thickness of 365 μm.
However, a part of the negative electrode 2 has a hole of the metal substrate and a part in which the active material layer is formed only on one surface. Specifically, the total length of the negative electrode 2 is 67 mm, but one of the metal substrate 2a On the surface, the active material layer is not formed from one end E to the other end F up to 26 mm,
After that, the active material layer 2b is continuously formed up to the other end F, and the other surface of the metal substrate 2a extends from one end E to the other end F up to 63.2 mm. The active material layer 2c is formed, and the remaining 3.8 mm is not formed. The width of the negative electrode 2 is 35 mm.

The negative electrode 2 and the positive electrode 1 were spirally wound with the separator 3 interposed therebetween to produce an electrode body having a wound structure shown in FIG. However, in manufacturing the electrode body having the above-mentioned wound structure, the separator 3 is folded back at the center thereof.
It was arranged so as to cover both surfaces of the negative electrode 2, and was wound in a spiral shape with the end F (see FIG. 10) side being the center side of the spiral. Also in this case, at least the active material layer 2b or 2c of the negative electrode 2 faces the positive electrode 1 with the separator 3 interposed therebetween. In addition, both FIG. 10 and FIG.
This is schematically shown, and for example, the thickness of the metal substrate 2a and the thicknesses of the active material layers 2b and 2c are illustrated to be large with respect to the length of the negative electrode 2, and the active material layer of the negative electrode 2 is formed. The positions and widths of the portions that are not shown are not necessarily shown according to the dimensions. Further, regarding the electrode body having the winding structure shown in FIG. 11, a portion not shown in FIG. 11 will be described. The active material layer 2b is formed at substantially the innermost peripheral portion of the negative electrode 2.
Only the positive electrode 1 (see FIG. 10) faces the positive electrode 1 via the separator 3, and the active material layer 2c (FIG.
Of the active material layer 2 is opposed to the positive electrode 1 with the separator 3 interposed therebetween.
b and 2c face the positive electrode 1 via the separator.
Similarly, although not shown in FIG. 11, a metal substrate is exposed on the outer surface side of the outermost peripheral portion of the negative electrode 2, and the metal substrate is in contact with the inner wall of the battery can 5. FIG.
Since the metal substrate is not shown in FIG. 1, it is similar to FIG.

The positive electrode 1 is made of the same paste type nickel electrode as in the first embodiment, and the positive electrode 1 has a thickness of 660 μm.
m and its size is 35 mm x 46 mm. The separator 3 has the same thickness of 0.15 as in the first embodiment.
mm non-woven polypropylene fabric, size 102
mm × 38 mm.

Then, using the electrode body having the winding structure produced by using the positive electrode 1, the negative electrode 2 and the separator 3, the same procedure as in Example 1 is carried out. A secondary battery was produced.

This battery is regulated by the positive electrode and the theoretical electric capacity of the positive electrode is 600 mAh.
FIG. 13 shows the discharge characteristics when discharged by A discharge. The filling theoretical electric capacity of the negative electrode was 977 mAh, and the ratio of [negative electrode electric capacity] / [positive electrode electric capacity] in this battery was 1.63. Further, in FIG. 13, the characters of Example 4 and Example 5 are added to the same curve in that the discharge characteristics of Example 5 have almost no difference from the discharge characteristics of Example 4, and the difference between the two is the same. This is because the discharge characteristics of both of them cannot be clearly illustrated in FIG. 13 and are represented by a single curve.

Comparative Example 1 23 parts by weight of a binder solution prepared by dissolving polyvinyl alcohol in water at a concentration of 2.6% was added to 100 parts by weight of a hydrogen-absorbing alloy powder mainly composed of MmNi ₅ and mixed, followed by thorough stirring. Thus, a uniform paste was prepared, and this paste was filled in a foamed nickel plate having a thickness of 600 μm, dried and then compressed by a roll press to prepare a negative electrode sheet. However, this negative electrode sheet had a thickness of 250 μm and a size of 35 mm × 6 so that the ratio of [electrical capacity of negative electrode] / [electrical capacity of positive electrode] at a portion facing the positive electrode described later was 1.3.
It was set to 7 mm.

The positive electrode was made of the same paste-type nickel electrode as in Example 1, but in order to set the ratio of [electric capacity of negative electrode] / [electric capacity of positive electrode] at the portion facing the negative electrode to 1.3,
The thickness was 430 μm, and the size was 35 mm × 51 mm.

A polypropylene nonwoven fabric similar to that used in Example 1 was used as the separator, and the nonwoven fabric was interposed between the negative electrode and the positive electrode and spirally wound to produce an electrode body having a winding structure shown in FIG. In the same manner as in Example 1, a nickel-hydrogen storage alloy alkaline secondary battery of a AAA type was produced. Reference numeral 12 in FIG. 12 corresponds to one end portion of the positive electrode lead body, and this portion is welded to the exposed portion of the positive electrode substrate, and the whole thereof constitutes a positive electrode current collector.

This battery is regulated by the positive electrode and the theoretical electric capacity of filling the positive electrode is 410 mAh.
FIG. 13 shows the discharge characteristics when discharged by A discharge. The theoretical filling electric capacity of the negative electrode is 680 mAh. However, the negative electrode facing the positive electrode is 530 mAh, and the ratio of [electric capacity of the negative electrode] / [electric capacity of the positive electrode] of this battery is 1.3 as described above.

FIG. 13 shows the above Examples 1 to 5 and Comparative Example 1
13 is a discharge characteristic diagram of the battery of Example 1. As shown in FIG. 13, Examples 1 to 5 have a larger discharge capacity than that of Comparative Example 1, and achieve an increase in discharge capacity of about 30%. I was able to.

Although the nickel-hydrogen storage alloy type alkaline secondary battery has been described in the above embodiment, the present invention is
Other than the nickel-hydrogen storage alloy battery, various batteries having a wound structure, for example, nickel-cadmium battery, nickel-iron battery, alkaline battery typified by nickel-zinc battery, lithium-manganese battery, lithium-ion battery, etc. Can also be applied to.

[0065]

As described above, according to the present invention,
An increase in capacity could be achieved. Further, according to the present invention, since the negative electrode can be produced by a simple coating method, the productivity can be improved, and an expensive foam metal or a sintered plate can be used only by using a metal substrate as the substrate. Therefore, cost reduction can be achieved. Furthermore, according to the present invention, since the surface of the battery can that contacts the inner wall is the metal substrate, the inner wall of the battery can is not scratched by the hydrogen storage alloy or the like, and the reliability can be improved.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view schematically showing an electrode body having a wound structure used for a battery of Example 1.

FIG. 2 is an enlarged view of a Y portion of FIG.

FIG. 3 is a cross-sectional view schematically showing the alkaline secondary battery of Example 1.

FIG. 4 schematically shows a negative electrode used in the battery of Example 2, where (a) is a side view of the negative electrode on which the active material layer is formed, and (b) is the same as the above (a). It is a sectional view taken along line XX.

5 is a cross-sectional view schematically showing an electrode body having a wound structure used in the battery of Example 2. FIG.

FIG. 6 schematically shows a negative electrode used in the battery of Example 3, (a) of which is a side view of the side of the negative electrode on which an active material layer is formed, and (b) of (a) above. It is a sectional view taken along the line WW.

FIG. 7 is a cross-sectional view schematically showing an electrode body having a wound structure used in the battery of Example 3.

FIG. 8 schematically shows a negative electrode used in the battery of Example 4, where (a) is one side view of the negative electrode, (b) is another side view of the negative electrode, and (c) thereof. 8A is a sectional view taken along line VV of FIG.

FIG. 9 is a cross-sectional view schematically showing an electrode body having a wound structure used in the battery of Example 4.

FIG. 10 schematically shows a negative electrode used in the battery of Example 5, where (a) is one side view of the negative electrode and (b) is a side view thereof.
[Fig. 3] is a side view of the other side of the negative electrode.
It is a sectional view taken along line U-U of FIG.

FIG. 11 is a cross-sectional view schematically showing an electrode body having a wound structure used in the battery of Example 5.

12 is a cross-sectional view schematically showing an electrode body having a wound structure used in the battery of Comparative Example 1. FIG.

13 is a discharge characteristic diagram of the batteries of Examples 1 to 5 and Comparative Example 1. FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Positive electrode 2 Negative electrode 2a Metal substrate 2b Active material layer 2c Active material layer 3 Separator 4 Winding structure electrode body 5 Battery can

Claims (9)

[Claims] 1. In a battery produced by inserting an electrode body having a wound structure in which a positive electrode and a negative electrode are wound via a separator into a battery can, the negative electrode faces both sides of the positive electrode through the separator, and the A battery having a wound structure electrode body in which the negative electrodes are in direct contact with each other after the second round. 2. The negative electrode comprises an active material layer formed only on one side of the metal substrate or in a hole provided in the metal substrate and only on one side of the metal substrate, and the active material layer of the negative electrode is provided with a separator interposed therebetween. The battery according to claim 1, which is opposed to the positive electrode. 3. In a battery prepared by inserting an electrode body having a wound structure in which a positive electrode and a negative electrode are wound with a separator interposed between them into a battery can, the negative electrode has active material layers formed on both sides of a metal substrate. , The portion corresponding to either the innermost portion or the outermost portion of the wound electrode body is only on one side of the metal substrate or in the holes provided in the metal substrate and only on one side of the metal substrate. It consists of the one without active material layer,
A battery having an electrode body having a wound structure in which an active material layer of the negative electrode faces the positive electrode via a separator. 4. In a battery prepared by inserting an electrode body having a wound structure in which a positive electrode and a negative electrode are wound with a separator interposed between them into a battery can, the negative electrode has active material layers formed on both sides of a metal substrate. The active material layer is formed only on one side of the metal substrate or in the holes provided in the metal substrate and only on one side of the metal substrate in the portions corresponding to the innermost portion and the outermost portion of the wound electrode body. A battery characterized in that it has an electrode body of a wound structure in which the active material layer of the negative electrode faces the positive electrode via the separator. 5. The outermost peripheral portion of the electrode body is a negative electrode, and the metal substrate of the negative electrode is present outside and is in contact with the inner wall of the battery can. The battery according to 4. 6. The metal substrate of the negative electrode has a thickness of 10 μm to 50 μm.
A metal plate having a thickness of μm.
The battery according to 3, 4, or 5. 7. The negative electrode metal substrate has a thickness of 40 μm to 70 μm.
The battery according to claim 1, 2, 3, 4, or 5, comprising a punched metal plate of μm. 8. The current collecting part is provided on the outermost peripheral part of the positive electrode, and the positive electrode collects current from the current collecting part.
The battery according to 2, 3, 4, 5, 6 or 7. 9. Regarding the portion of the negative electrode facing the positive electrode, the amount of active material in the inner peripheral portion of the negative electrode is the same as the amount of active material in the outer peripheral portion, or the amount of active material in the inner peripheral portion is the active material in the outer peripheral portion. The amount of active material in the inner peripheral portion of the negative electrode is 1 to 1.6 times the amount of active material in the outer peripheral portion.
The battery according to 3, 4, 5, 6, 7 or 8.