JPH06223841A - Swirl type electrode for battery - Google Patents

Abstract

PURPOSE:To reduce volume loss and improve capacity by forming the outer periphery of an electrode into the same shape as a real circle with the radius being a preset distance at completion of wind-up of a band positive electrode and a band negative electrode from the axial center. CONSTITUTION:At the completion of winding a band positive electrode plate 1 and a band negative electrode plate 2 the end opposing above both electrode plates is positioned on the extension viewing the plane part in the direction of width of thin film stripe 4 located at 230-320 degree from the end opposing to both electrode plates at starting of winding from an axial center. Then, it can be wound up longer than the positive electrode plate 1 and the negative electrode plate 2, an area (a) which is formed to stop the end of wind-up shifted from a real circle of a battery can within a real circuit of the battery can is reduced. As a result, the volume loss of an electrode A via which a current collector 5 is jointed to the stripe 4 can be reduced and the capacity is improved because of a smaller gap when it is mounted.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spiral-wound electrode body for batteries used in hydrogen storage alloy batteries and the like, and more particularly to a thin-walled electrode plate provided on at least one of a strip-shaped positive electrode plate and a strip-shaped negative electrode plate over the entire width. The present invention relates to a spiral-wound electrode body for a battery in which capacity is improved by minimizing the volume loss of the spiral-wound electrode body for a battery in which a plate-shaped current collector is joined to a stripe.

[0002]

2. Description of the Related Art Generally, as shown in FIG. 5, a spirally wound electrode body for a battery used in a small-sized and small-capacity hydrogen storage alloy battery has a porous metal sheet of nickel hydroxide or the like. A strip-shaped positive electrode plate 1 filled with a positive electrode active material, and a strip-shaped negative electrode plate 2 in which a hydrogen-absorbing alloy and a porous metal body are integrally formed in a sheet shape are placed via a separator 3 made of a synthetic fiber nonwoven fabric. A thin stripe 4 which is spirally wound and is not filled with the positive electrode active material is formed on a part of the strip-shaped positive electrode plate 1 over the entire width of the electrode plate.
It is provided at one place or at a plurality of places as shown in FIG. 6, and plate-shaped current collectors 5 are joined to these thin stripes 4, respectively.

[0003]

Therefore, in these conventional spirally wound electrode bodies D and E for batteries, the outer peripheral shape deviates from the perfect circle of the battery can due to the positional relationship between the winding start and winding end, and the positive electrode active Since the plate-shaped current collector 5 is bonded to the thin stripe 4 which is not filled with the substance, the thickness of the spirally wound electrode body is partially thinned and becomes flat at this portion,
The outer shape deviates from the perfect circle of the battery can. As a result,
Further, as shown in FIG. 6, a portion a formed to stop the winding end of the strip-shaped positive electrode plate 1 and the strip-shaped negative electrode plate 2 deviated from the true circle of the battery can within the true circle of the battery can, and the current collector 5. By joining to the thin stripe 4, a portion b which is formed off the true circle of the battery can is generated, resulting in a volume loss,
It has the drawback of reduced capacity.

The present invention eliminates the above drawbacks and provides a spiral-wound electrode body for a battery, in which a plate-shaped current collector is joined to a thin-walled strip extending over the entire width of an electrode plate provided on at least one of the band-shaped positive electrode plate and the band-shaped negative electrode plate. Reduce volume loss as much as possible,
It is an object of the present invention to provide a spirally wound electrode body for a battery having an improved capacity.

[0005]

In the present invention, a strip-shaped positive electrode plate and a strip-shaped negative electrode plate are wound around a separator,
A strip-shaped positive electrode plate or strip-shaped negative electrode plate is provided with a thin stripe over the entire width of the electrode plate, and a plate-shaped current collector is joined to this thin wall stripe, making the total thickness of the thin-walled stripe and the current collector smaller than the thickness of the electrode plate. In the spirally wound electrode body for a battery, the ends of the strip-shaped positive electrode plate and the strip-shaped negative electrode plate facing each other at the end of winding are thin striped strips positioned at an angle of 230 to 320 degrees from the end at which the electrode plates face each other at the beginning of winding. The outer shape of the outer periphery of the spirally wound electrode body for a battery on the extension of the flat portion in the width direction from the shaft core is the outermost end of both ends of the strip-shaped positive electrode plate and the strip-shaped negative electrode plate at the end of winding. It is designed to be almost the same as a perfect circle whose radius is the distance to.

Further, the strip-shaped positive electrode plate and the strip-shaped negative electrode plate are wound with a separator interposed therebetween, and at least one of the strip-shaped positive electrode plate and the strip-shaped negative electrode plate is provided with two or more thin-walled stripes over the entire width of the polar plate. In a spiral-wound electrode body for a battery, in which a plate-shaped current collector is bonded to these thin stripes, and the total thickness of the thin stripe and the current collector is thinner than the thickness of the electrode plate,
At the winding end of the strip-shaped positive electrode plate and the strip-shaped negative electrode plate, the opposite ends of the bipolar plates are located at an angle of 230 to 320 degrees from the opposite ends of the bipolar plates at the beginning of winding. On the extension to face,
The shape of the outer circumference of the spirally wound electrode body for a battery is almost the same as a perfect circle whose radius is the distance from the axial center to the outermost end of the opposite ends of the strip-shaped positive electrode plate and the strip-shaped negative electrode plate at the end of winding. I have to.

[0007]

Since the spiral wound electrode body for a battery of the present invention is configured as described above, the spiral wound electrode body for a battery in which a plate-shaped current collector is joined to a thin strip of the strip positive electrode plate or the strip negative electrode plate. The volume loss is minimized and the capacity is sufficiently improved.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the spiral electrode body for a battery of the present invention will be described below with reference to the drawings. FIG. 1 shows an example of a spirally wound electrode body for a battery according to the present invention. The spirally wound electrode body A for a battery is a strip-shaped positive electrode plate 1 in which a sheet of a metal porous body is filled with a positive electrode active material. , Sheet-shaped strip negative electrode plate 2
And spirally wound via a separator 3, and a thin-walled stripe 4 not filled with the positive electrode active material is provided over the entire width of the electrode plate at approximately the center in the lengthwise direction of the strip-shaped positive electrode plate 1. The thin stripe 4 is joined to a plate-shaped current collector 5.

Then, the strip-shaped positive electrode plate 1 and the strip-shaped negative electrode plate 2
At the end of winding, the strip-shaped positive electrode plate 1 and the strip-shaped negative electrode plate 2
The edge G of the portion facing each other in the widthwise plane of the thin stripe 4 located at an angle α of 230 to 320 degrees from the edge S of the portion where the strip-shaped positive electrode plate 1 and the strip-shaped negative electrode plate 2 face each other at the beginning of winding of the bipolar plates. It is on the extension that faces the part from the axis,
The shape of the outer periphery of the spirally wound electrode body A for a battery is a perfect circle having a radius r from the axial center to the outermost end of the end G where the two electrode plates face each other at the end of winding of the belt-shaped positive electrode plate 1 and the belt-shaped negative electrode plate 2. I try to be almost the same.

Therefore, the spiral electrode body A for the battery is
As shown in FIG. 1, the end G of the portion where the bipolar plates face each other at the end of winding of the strip positive electrode plate 1 and the strip negative electrode plate 2 is always at an angle 230 from the end S of the portion where the bipolar plates face each other at the beginning of winding of the bipolar plate. A strip-shaped positive electrode plate 1 and a strip-shaped negative electrode plate 2 can be wound for a longer period, reaching a flattened thin portion on an extension facing the widthwise flat portion of the thin stripe 4 located in the range α of 320 degrees. The portion a formed to stop the winding end of the strip positive electrode plate 1 and the strip negative electrode plate 2 deviating from the true circle of the battery can within the true circle of the battery can becomes smaller.

At the same time, the current collector 5 is attached to the thin stripe 4
The portion b formed by deviating from the true circle of the battery can becomes smaller due to the joining to, and the outer shape becomes closer to the true circle of the battery can.

Therefore, the strip-shaped positive electrode plate 1 or the strip-shaped negative electrode plate 2
The volume loss of the spiral electrode for battery A in which the plate-shaped current collector 5 is joined to the thin stripe 4 can be made as small as possible, and the gap when mounted in the cylindrical battery can is made small. Therefore, the capacity can be improved.

In the case of a hydrogen storage alloy battery, the strip-shaped positive electrode plate 1 in such a spirally wound electrode body A for a battery is composed of nickel hydroxide powder as a paste together with a conductive auxiliary agent, a binder and the like, and a wire mesh. It is formed by filling a sheet of a metal porous body such as expanded metal, and then drying, aging and adjusting the thickness.

The strip-shaped positive and negative electrode plate 2 is formed into a sheet by compression-molding a hydrogen-absorbing alloy integrally with a metal porous body such as a wire mesh or expanded metal and sintering it. As the binder 3, a non-woven fabric such as polypropylene fiber is used.

Here, the strip positive electrode plate 1 and the strip positive and negative electrode plate 2
It is preferable that the thickness ratio of the strip-shaped positive electrode plate 1 / the strip-shaped positive and negative electrode plate 2 be within the range of 4/1 to 1.5 / 1. If the strip-shaped positive electrode plate 1 is thicker than this range, The electrical balance between the amount of the positive electrode active material and the amount of the negative electrode active material is disrupted, which adversely affects cycle characteristics and the like, and when it is too thin, the capacity of the battery determined by the amount of the positive electrode active material becomes small,
There is a problem in that it causes inconvenience in use.

Further, the thin-walled stripes 4 formed at substantially the center of the strip-shaped positive electrode plate 1 in the lengthwise direction are matched with the width of the current collector 5 and the positive electrode active material such as nickel hydroxide powder is spread over the entire width of the strip-shaped positive electrode plate 1. Plate-shaped current collector 5 made of stainless steel, nickel, etc.
Are joined by welding or eyelets.

Here, if the width of the plate-shaped current collector 5 is smaller than 1/7 of the diameter of the spirally wound electrode body A for a battery, sufficient current collection cannot be performed, and if it is larger than 1/3, it is strip-shaped. At the end of winding of the positive electrode plate 1 and the strip-shaped negative electrode plate 2, a portion a formed to prevent the end G where the both electrode plates face each other from deviating from the true circle of the battery can, and the current collector 5 are joined to the thin stripe 4. As a result, the portion b formed off the true circle of the battery can becomes large, and the volume loss cannot be made as small as possible.
The size is preferably 7 to 1/3, and 1/6 to 1 /
A size of 4 is more preferable.

In order to improve the current collecting efficiency of the current collector 5, the thin stripe 4 of the strip-shaped positive electrode plate 1 is provided in the substantially central portion of the strip-shaped positive electrode plate 1 in the length direction, and the thin striped stripe 4 is formed. Although it is preferable to join the plate-shaped current collector 5, the thin stripes 4 do not necessarily have to be provided substantially at the center of the strip-shaped positive electrode plate 1 in the longitudinal direction, and can be provided at appropriate positions.

Further, in the embodiment shown in FIG. 1, the strip positive electrode plate 1 is provided with the thin stripes 4, but the thin strips may be provided without filling the strip negative electrode plate 2 with the negative electrode active material. The same effect can be obtained when a thin stripe is provided on the electrode plate.

FIG. 2 shows an example in which such a spiral electrode A for a battery is used in a hydrogen storage alloy battery. The spiral electrode A for a battery has a cylindrical shape with a bottom and a constricted portion at the top. It is mounted in a battery can 6 having the above, and the top end extension of the current collector 5 is used as a current collecting terminal 7 and connected to a dish-shaped sealing plate 8 having a gas inspection hole 8a in the center.

A cap-shaped terminal plate 9 is integrally connected to the upper side of the sealing plate 8 by sandwiching the peripheral edge of the bent peripheral edge of the sealing plate 8. A valve body 11 having a gas inspection hole 8a mounted on the lower bottom of the inside 8 so as to be openable and closable is being pressed.

Reference numeral 9a is a gas discharge hole provided on the side wall of the terminal plate 9. When gas is generated inside the battery and the internal pressure of the battery rises, the metal spring 10 contracts and the valve body 11 opens to open the battery. The gas inside is discharged to the outside of the battery through the gas inspection hole 8a and the gas discharge hole 9a, and the battery is prevented from bursting.

Reference numeral 12 denotes an annular gasket fitted inside the inwardly curved portion of the upper portion of the battery can 6, and the sealing plate 8 sandwiching the terminal plate 9 with the annular gasket 12 is provided inside the inwardly curved portion of the upper portion of the battery can 6. It is fitted and supported.

Numeral 13 is an insulator disposed directly above the spirally wound electrode body A for batteries mounted in the battery can 6, and 14 is directly below the spirally wound electrode body A for batteries and is the bottom of the battery can 6. It is an insulator disposed between and.

Further, the battery can 6 is connected to the strip-shaped negative electrode plate 2 of the spirally wound electrode body A for a battery and acts as a negative electrode can. Inside the battery can 6, a high-concentration aqueous solution of alkali hydroxide is used as an alkaline electrolyte. Has been injected.

FIG. 3 shows another example of the spirally wound electrode body for a battery according to the present invention. In this spirally wound electrode body for a battery B, the positive electrode active material is not filled in three places of the strip-shaped positive electrode plate 1. The thin stripes 4a, 4b, 4c are provided over the entire width of the electrode plate, and plate-shaped current collectors 5a, 5b, 5c are joined to these thin stripes 4a, 4b, 4c.

Then, the strip-shaped positive electrode plate 1 and the strip-shaped negative electrode plate 2
At the end of winding, the end G of the part where the both electrodes are opposite,
At the beginning of winding the bipolar plate, the end S of the portion where the bipolar plate faces
From the axis to the strip-shaped positive electrode plate 1 on the extension of the width direction flat surface portion of the thin stripe 4a positioned in the range α of 230 to 320 degrees from the axis to the axis. And for the battery shown in FIG. 1 and FIG. 2 except that it is made substantially the same as a perfect circle having a radius r at the end of winding of the strip-shaped negative electrode plate 2 to the outermost end of the end G where the two electrode plates face each other. It is configured in the same manner as the spiral electrode body A.

Therefore, the spiral electrode body B for the battery is
As shown in FIG. 3, the end G of the portion where the bipolar plates face each other at the end of the winding of the strip positive electrode plate 1 and the strip negative electrode plate 2 is always at an angle 255 from the end S of the portion where the bipolar plates face each other at the beginning of the winding of the bipolar plate. To the flat surface portion on the extension of the width direction flat surface portion of the thin stripe 4a located in the range α of up to 320 degrees, the strip positive electrode plate 1 and the strip negative electrode plate 2 are reached.
Can be wound longer, and the portion a formed to stop the winding end of the strip-shaped positive electrode plate 1 and the strip-shaped negative electrode plate 2 deviating from the perfect circle of the battery can within the perfect circle of the battery can becomes smaller.

Further, since the current collector 5a is joined to the thin stripe 4a at the same time, the portion b formed off the true circle of the battery can becomes smaller, and the outer shape becomes closer to the true circle of the battery can. .

Therefore, the strip-shaped positive electrode plate 1 or the strip-shaped negative electrode plate 2
Plate-shaped current collector 5 on thin stripes 4a, 4b, 4c
It is possible to reduce the volume loss of the spiral-wound electrode body B for a battery joining the a, 5b, and 5c as much as possible, and to reduce the gap when it is mounted in a cylindrical battery can, thereby reducing the capacity. Can be improved.

In the spirally wound electrode body B for a battery shown in FIG. 3, a thin stripe or a current collector may be provided without filling the strip-shaped negative electrode plate 2 with the negative electrode active material. The same as in the case of the spiral wound electrode body A for a battery shown in 2, the ratio of the material and thickness of the strip positive electrode plate 1 and the strip negative electrode plate 2, and further the spiral wound electrode body for a battery of the current collectors 5a, 5b, 5c. B
The ratio and the like to the diameter are the same as in the case of the spiral electrode body A for a battery.

The spiral electrode bodies A and B for batteries of the present invention
Is used for hydrogen storage alloy batteries as described above, but is also used for spiral lithium batteries, nickel-cadmium batteries and the like.

When used in a battery having a small size and a small capacity, the spiral electrode bodies A and B for a battery as described above are thin-walled in which at least one of the strip-shaped positive electrode plate and the strip-shaped negative electrode plate is provided without being filled with an active material. The stripes are particularly effective because they can reduce the portion where the action as the electrode plate is reduced as much as possible, and can collect current efficiently.

On the other hand, in the case where the capacity is large and the portion reduced by the thin stripe is large, as shown in FIG. 4, the strip-shaped positive electrode plate 1b in which the upper and lower ends are spirally wound, and Thin strips 4d and 4e continuous in the length direction of the strip positive electrode plate 1b and the strip negative electrode plate 2b are provided at the ears of the projecting ends of the strip negative electrode plate 2b, respectively. By connecting the electric bodies 5d and 5e, it is possible to reduce the volume loss of the spiral electrode body C for a battery. Therefore, such a structure may be adopted in the spirally wound electrode body for a battery having a large capacity.

In FIG. 4, 3b is a separator,
6b is a battery can, 8b is a sealing plate, 7b is a current collecting terminal for connecting a disk-shaped current collector 5d to the sealing plate 8b, 9b is a terminal plate, 10b is a metal spring, 11b is a valve body, and 12b is a gasket. , 13b are positive electrode insulators.

[0036]

As described above, according to the present invention, the strip-shaped positive electrode plate and the strip-shaped negative electrode plate are wound via the separator, and the strip-shaped positive electrode plate or strip-shaped negative electrode plate is thinned over the entire width of the electrode plate. In a spiral-wound electrode assembly for a battery, in which a strip is provided and a plate-shaped collector is joined to this thin stripe, and the total thickness of the thin stripe and the collector is smaller than the thickness of the electrode plate,
At the winding end of the strip-shaped positive electrode plate and the strip-shaped negative electrode plate, the opposite ends of the bipolar plates are located at an angle of 230 to 320 degrees from the opposite ends of the bipolar plates at the beginning of winding. On the extension to face,
The shape of the outer circumference of the spirally wound electrode body for a battery is almost the same as a perfect circle whose radius is the distance from the axial center to the outermost end of the opposite ends of the strip-shaped positive electrode plate and the strip-shaped negative electrode plate at the end of winding. Therefore, it is possible to minimize the volume loss of the spirally wound electrode body for a battery in which the plate-shaped current collector is joined to the thin stripe of the strip-shaped positive electrode plate or the strip-shaped negative electrode plate, and to improve the capacity. You can

Further, the strip-shaped positive electrode plate and the strip-shaped negative electrode plate are wound with a separator interposed therebetween, and at least one of the strip-shaped positive electrode plate and the strip-shaped negative electrode plate is provided with two or more thin-walled stripes extending over the entire width of the electrode plate. A plate-shaped current collector is joined to these thin stripes, and the spiral type electrode body for a battery in which the total thickness of the thin stripe and the current collector is smaller than the thickness of the electrode plate also includes the strip-shaped positive electrode plate and the strip-shaped negative electrode plate. At the end of winding, the ends where the bipolar plates face each other are on an extension of the thin-walled stripes located in the range of an angle of 230 to 320 degrees from the ends where the bipolar plates face at the beginning of winding so as to face the flat portion in the width direction from the axis, and the battery is The outer shape of the spiral type electrode body for use is approximately the same as a perfect circle having a radius from the axial center to the outermost end of the opposite ends of the strip-shaped positive electrode plate and the strip-shaped negative electrode plate at the end of winding. Are therefore, the volume loss of the band-like positive electrode plate or strip-shaped negative electrode plate for battery vortex electrode body joining planar collector thin stripes becomes as small as possible, the capacity is sufficiently improved.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an example of a spiral electrode body for a battery of the present invention.

FIG. 2 is a longitudinal sectional view of a hydrogen storage alloy battery using the spiral electrode body for a battery of the present invention.

FIG. 3 is a transverse sectional view showing another example of the spiral electrode body for a battery of the present invention.

FIG. 4 is a partially developed perspective sectional view showing still another example of the spiral electrode body for a battery of the present invention.

FIG. 5 is a cross-sectional view showing an example of a conventional spiral electrode body for a battery.

FIG. 6 is a cross-sectional view showing another example of a conventional spiral wound electrode body for a battery.

[Explanation of symbols]

1 band-shaped positive electrode plate 2 band-shaped negative electrode plate 3 separator 4, 4a, 4b, 4c, 4d thin stripes 5, 5a, 5b, 5c, 5d collector 6 battery can A, B, C spiral electrode body for battery S Winding start G Winding end α At the beginning of winding, angle 23 from the end where the bipolar plates face each other.
0-320 degree range

Claims (4)

[Claims] 1. A strip-shaped positive electrode plate and a strip-shaped negative electrode plate are wound with a separator interposed therebetween, and a strip-shaped positive electrode plate or strip-shaped negative electrode plate is provided with a thin stripe over the entire width of the electrode plate. In a spiral-wound electrode body for a battery in which the body is joined and the total thickness of the thin-walled stripe and the current collector is thinner than the thickness of the electrode plate, the ends where both electrode plates face each other at the winding end of the strip positive electrode plate and the strip negative electrode plate, At the beginning of winding, the widthwise flat portion of the thin stripe located in the range of an angle of 230 to 320 degrees from the ends where the bipolar plates face each other is on the extension facing the axis from the axis, and the shape of the outer periphery of the spiral electrode for battery is the axis. A spiral electrode body for a battery, which is substantially the same as a perfect circle whose radius is the distance from the core to the outermost end of the opposite ends of the strip-shaped positive electrode plate and the strip-shaped negative electrode plate at the end of winding. 2. A strip-shaped positive electrode plate and a strip-shaped negative electrode plate are wound around a separator, and at least one of the strip-shaped positive electrode plate and the strip-shaped negative electrode plate is provided with two or more thin-walled stripes over the entire width of the polar plate. In a spiral-wound electrode body for a battery in which a plate-shaped current collector is joined to these thin stripes and the total thickness of the thin stripe and the current collector is smaller than the thickness of the electrode plate, At the end, the opposite ends of the bipolar plates are on an extension of the thin-walled stripes located in the range of an angle of 230 to 320 degrees from the ends at which the bipolar plates face at the beginning of winding, facing the axial center from the axial center, and for a battery. It is characterized in that the outer shape of the spirally wound electrode body is almost the same as a perfect circle whose radius is the distance from the axial center to the outermost end of the opposite ends of the strip-shaped positive electrode plate and the strip-shaped negative electrode plate at the end of winding. To Swirl type electrode body for batteries 3. The strip-shaped positive electrode plate and the strip-shaped negative electrode plate have a thickness ratio of 4/1 to 1.5 / in terms of a strip-shaped positive electrode plate / strip-shaped negative electrode plate ratio.
The spiral electrode body for a battery according to claim 1 or 2, wherein 4. The spiral electrode body for a battery according to claim 1, wherein the width of the current collector is 1/7 to 1/3 of the diameter of the spiral electrode body for the battery.