JP3782160B2 - Winding electrode manufacturing method and manufacturing apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a manufacturing method and a manufacturing apparatus capable of manufacturing a cylindrical electrode having a high capacity with a high yield.
[0002]
[Prior art]
In recent years, as electronic devices such as mobile phones and portable notebook computers are made coatless, have higher performance, and are smaller and lighter, it is required to increase the capacity of secondary batteries serving as power sources for these electronic devices. ing. That is, as a secondary battery serving as a power source, a nickel metal hydride secondary battery has been put into practical use in place of the conventionally used lead storage battery and nickel cadmium battery.
[0003]
By the way, this type of secondary battery generally includes a wound electrode (electromotive portion) formed by winding a laminate of a positive electrode sheet, an interlayer insulating sheet, a negative electrode sheet, and an interlayer insulating sheet. The structure is liquid-tightly sealed in a shaped outer container. And the wound electrode of this cylindrical battery usually sandwiches one or two strip-shaped separators (interlayer insulation sheet) by a pair of core rods (core bodies) having a semi-cylindrical portion. In addition, after the strip-shaped positive electrode sheet and the strip-shaped negative electrode sheet are arranged along the separator, the core rod is rotated so as to be wound in a spiral shape.
[0004]
FIG. 3 is a plan view showing the main configuration of a manufacturing apparatus conventionally used for manufacturing a wound electrode. Here, 1 is a winding mechanism main body having a winding core body 1a for winding a belt-like positive electrode sheet 2, a belt-like negative electrode sheet 3 and belt-like interlayer insulating sheets 4, 4 'in a spiral shape, A guide mechanism for running and supplying the positive electrode sheet 2, the interlayer insulating sheet 4, the negative electrode sheet 3 and the interlayer insulating sheet 4 ′ separately to the core body 1 a of the mechanism body 1, Installed in a movable / retractable type with respect to the core body 1a of the mechanism body 1, and presses the outer peripheral surface of the wound electrode formed in a spiral shape on the core body 1a with a certain pressure. This is a pressure roller that achieves dense winding.
[0005]
In this configuration, the winding core body 1a of the winding mechanism main body 1 includes a semi-cylindrical section that forms an opposed flat surface portion so that the interlayer insulating sheet can be sandwiched. The guide mechanism 5, the guide block 5 _1, 5 _2, 5 _3, 5 ₄ turned into, the guide block 5 _1, 5 _2, 5 _3, 5 ₄ combinations, the required travel path 5a, 5b, 5c and 5d are formed, and the guide blocks 5 ₁ , 5 ₂ , 5 ₃ , and 5 ₄ are slidable by the vacuum air so that the interlayer insulating sheets 4 and 4 ′ are slid on the travel surface. It is supposed to be retained.
[0006]
And the manufacture of the winding type electrode by this manufacturing apparatus is performed as follows. That is, an interlayer insulating sheet (separator) is sandwiched between opposing flat surfaces of the winding core 1a, the negative electrode sheet 3 is sandwiched between the interlayer insulating sheets 4, and the positive electrode sheet 2 is disposed between the interlayer insulating sheets 4 '. While being supplied in the form of each, it winds by rotating and driving the core 1a of the winding mechanism body 1. In other words, while the sheets 2, 3, 4 and 4 'are stacked and wound around the core 1a in a spiral shape, the outer peripheral surface of the spiral is formed by the pressure rollers 6a and 6b at a constant pressure. To produce a wound electrode (electromotive part).
[0007]
[Problems to be solved by the invention]
However, the conventional wound electrode manufacturing method has the following disadvantages. For example, the thickness of the positive electrode sheet 2 and the negative electrode sheet 3 tends to increase as the size and capacity of the nickel hydride secondary battery increase, and the positive electrode sheet 2 tends to increase on the outermost peripheral surface side of the wound electrode. The negative electrode sheet 3 wraps around the winding end terminal portion.
[0008]
Therefore, in the case of a wound electrode having a small diameter, the wound sheet end electrode is bent at an abrupt angle by the winding end step of the positive electrode sheet 2, and the wound electrode is damaged. There is a fear. Further, in the process of winding and forming the wound type electrode, the pressure rollers 6a and 6b for applying a certain pressure to the outer circumferential surface of the wound type electrode being formed are placed under the step where the positive electrode sheet 2 is wound. This causes the negative electrode sheet 3 to bite into the negative electrode sheet 3 and breaks through the interlayer insulating sheet 4 (4 ') to cause a short circuit. Here, when the constant pressure value by the pressure rollers 6a, 6b is lowered, the positive electrode sheet 2, the negative electrode sheet 3 and the interlayer insulating sheets 4, 4 'are densely wound, in other words, the number of winding layers is increased. As a result, the secondary battery cannot be increased in capacity.
[0009]
Accordingly, an object of the present invention is to provide a manufacturing method and a manufacturing apparatus that can be densely wound and can produce a wound electrode (electromotive part) for increasing the capacity with high yield.
[0010]
[Means for Solving the Problems]
The invention of claim 1 is a winding step of laminating and winding a belt-like positive electrode sheet, an interlayer insulating sheet, a negative electrode sheet and an interlayer insulating sheet on the winding core body, and winding the winding core body. A pressing step of pressing the outer peripheral surface of the cylindrical electrode facing the diameter direction with a rotary pressure roller with a substantially constant pressure, and in the pressing step, the winding of the positive electrode sheet is finished In a typical stage, the cylindrical electrode outer peripheral surface is pressed with a pressure smaller than the constant pressure .
[0011]
According to a second aspect of the present invention, there is provided a winding mechanism main body having a winding core body in which a belt-like positive electrode sheet, an interlayer insulating sheet, a negative electrode sheet, and an interlayer insulating sheet are laminated and spirally wound, A cylindrical electric holding block that is concentrically arranged opposite to each other and holds an outer peripheral surface of a cylindrical electrode that is wound and has a plurality of divided opposing surfaces each having a semi-cylindrical arc or less, and the cylindrical shape A plurality of pressure rollers that are arranged so as to be able to advance and retreat between the electrode holding blocks and are pressed against each other in a diametrical direction corresponding to the cylindrical electrodes wound around the winding core, and the pressure applied by the pressure rollers A pressure adjusting mechanism that can be adjusted and that reduces the pressure applied to the pressure roller from the pressure applied so far in a final winding stage after the positive electrode sheet has been wound. It is the manufacturing apparatus of the winding type electrode to be taken as.
[0012]
That is, in the present invention, a wound electrode forming sheet is spirally and cylindrically wound around a winding core body, and the outer peripheral surface of the cylindrical wound body is pressed with a pressure roller, and the dense winding is performed. The pressure applied by the pressure roller can be varied to selectively reduce the pressure applied by the pressure roller when the step formed by the end portion of the positive electrode sheet wrapped inside on the outer layer side passes. It is the essence of becoming.
[0013]
Thus, by selectively reducing / relaxing the pressure applied when the stepped portion formed by the terminal portion of the positive electrode sheet passes, the negative electrode sheet layer and the interlayer insulating sheet layer adjacent to the stepped portion, Since the possibility that the adjacent positive electrode sheet layer is damaged or damaged by excessive pressure is eliminated, a high-quality cylindrical electrode can be manufactured and provided with a high yield.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment will be described with reference to FIGS.
[0015]
FIG. 1 is a plan view showing the main configuration of a wound electrode manufacturing apparatus according to this embodiment. In FIG. 1, reference numeral 7 denotes a winding mechanism body having a winding core (winding rod) 7 a for winding a strip-shaped negative electrode sheet 8, a positive electrode sheet 9 and interlayer insulating sheets (separate) 10, 10 ′ in a spiral shape, A guide mechanism 11 supplies the positive electrode sheet 9, the first interlayer insulating sheet 10, the negative electrode sheet 8, and the second interlayer insulating sheet 10 'to the winding core 7a of the winding mechanism body 7. Here, the winding mechanism body 7 includes a rotation driving mechanism (not shown), and the winding core body 7a is rotated in the direction of the arrow by the rotation driving mechanism, and the winding core body 7a. Is configured to have a semicircular section in cross section that forms opposed flat surface portions so that the interlayer insulating sheet can be sandwiched.
[0016]
Further, 12a and 12b are arranged concentrically and oppositely to the core 7a, and a pair of opposing surfaces holding the outer peripheral surface of the cylindrical electrode to be wound has an arc of a half cylinder or less. Cylindrical electric holding blocks, 13a, 13b are arranged so as to be movable back and forth between the cylindrical electrode holding blocks 12a, 12b, and in the diametrical direction corresponding to the cylindrical electrodes wound and formed on the core 7a, For example, a pair of pressure rollers 15a and 15b pressed by the air cylinders 14a and 14b are pressure adjusting mechanisms that adjust the pressure of the air cylinders 14a and 14b to change the pressure applied to the pressure rollers 13a and 13b.
[0017]
Here, the cylindrical electrode holding blocks 12a and 12b hold the cylindrical electrode wound around the core 7a so as to spiral the electrode forming sheets 8, 9, 10, and 10 '. In the process of being wound in the shape, it is separated from the core 7a and stands by, and functions so as to approach the outer peripheral surface of the cylindrical electrode and hold it sandwiched after the end of winding. The pressure rollers 13a and 13b rotate in response to the rotation of the core body 7a, and pressurize the outer peripheral surface of the cylindrical electrode wound and formed on the core body 7a with a constant pressure. In order to achieve precise winding and formation. Accordingly, the pressure rollers 13a and 13b are installed so as to be capable of moving back and forth (moving) in the diameter direction of the core body 7a corresponding to the winding and formation of the cylindrical electrode. The pressure applied by the pressure rollers 13a and 13b is appropriately selected and adjusted according to the material and thickness of the electrode forming sheets 8, 9, 10, and 10 ', the capacity and dimensions of the cylindrical electrode, and the core body. in wound-formed final stage in 7a, so far to have pressure pressure drops below the (for example, pressure was reduced to less than about 75%) to be added is applied, configured as possible out switching of pressure It consists of.
[0018]
Next, a description will be given of an example of manufacturing a wound electrode by a manufacturing apparatus whose main configuration is shown in FIG.
[0019]
First, in order to act as the interlayer insulating sheets 10 and 10 'between the spaced apart and opposed flat portions of the winding core 7a, tape-like insulating sheets wound on both ends on a rewinding roller (not shown) are inserted. Or pinch. Here, the insulating sheet is, for example, a tape having a thickness of 0.2 mm and a width of 63 mm, and a tape-shaped positive electrode sheet 9 having a thickness of, for example, 0.6 mm and a width of 60 mm is disposed on one side, and the other side is, for example, thick. A tape-like negative electrode sheet 8 having a length of 0.3 mm and a width of 60 mm is disposed along the same.
[0020]
Next, the core body 7a is driven and rotated, and the guide mechanism 11 slides the laminated body of the positive electrode sheet 9 and the insulating sheet 10 and the laminated body of the negative electrode sheet 8 and the insulating sheet 10 ′. Then, it is wound in a spiral shape on the outer peripheral surface of the core body 7a. When winding in the spiral shape, the spiral / winding is advanced while the pair of pressure rollers 13a and 13b are in contact with the spiral / winding surface at a constant pressure. In other words, the vortex / winding is advanced in a state where a certain pressure is applied to the vortex / winding surface and the tension is applied, thereby performing precise vortex / winding without loosening.
[0021]
At the end of the spiral winding of the laminate of the positive electrode sheet 9 and the insulating sheet 10 and the laminate of the negative electrode sheet 8 and the insulating sheet 10 ', in other words, manufacture of a wound electrode corresponding to the battery capacity In the final stage of formation, after the winding of the positive electrode sheet 9 is finished, the laminated body of the negative electrode sheet 8 and the insulating sheet 10 ′ is passed (covered) beyond the winding terminal portion of the positive electrode sheet 9. A cylindrical electrode having an outer peripheral surface constituted by the negative electrode sheet 8 is finally formed.
[0022]
FIG. 2 is a cross-sectional view schematically showing a state in which the pressure rollers 13a and 13b are in contact with the outer peripheral surface of the spirally wound body at the end stage of the spirally wound body. As can be seen from FIG. 2, the winding end portion of the positive electrode sheet 9 forms a step with respect to the laminate of the negative electrode sheet 8 and the insulating sheet 10 ′ on the outer peripheral surface. By the way, according to the present invention, in the final winding stage, when the pressure rollers 13a and 13b pass through the winding end portion (stepped portion) of the positive electrode sheet 9, the constant pressure that has been applied until then is applied. Reduce or change. That is, in the final specific wound stage, the wound end portion of the positive electrode sheet 9 to form a step, the pressure roller 13a of the outer peripheral surface of the spiral Jomaki Sokarada corresponding to the step portion, a pair of 13b Selectively reduce contact pressure.
[0023]
Accordingly, the flat surface area of the outer peripheral surface is pressed with a constant pressure and dense winding is performed, while the stepped portion is prevented from being pressed with a local excessive pressure, so that the local portion applied to the stepped portion is avoided. Phenomena such as damage to the outer peripheral surface due to a large pressure and falling off of the active material of the negative electrode sheet 8 adjacent to the stepped portion are eliminated. In addition, a high capacity, small size and high quality cylindrical electrode (winding electrode) can be easily provided with a high yield, and thus a highly reliable secondary battery with high capacity can be provided.
[0024]
In addition, this invention is not limited to the said Example, A various deformation | transformation can be taken in the range which does not deviate from the meaning of invention. For example, the thickness and width of the insulating sheet, the positive electrode sheet, and the negative electrode sheet can be appropriately set according to the type and capacity of the target secondary battery.
[0025]
【The invention's effect】
According to the invention of claim 1, in the winding process of the tape-shaped positive electrode sheet, the tape-shaped negative electrode sheet and the interlayer insulating sheet (separator), an appropriate pressure is applied to the outer peripheral surface of the wound body, and the occurrence of looseness, etc. Wind while avoiding or suppressing. On the other hand, at the end stage of the winding process, the pressure in the stepped region formed on the outer peripheral surface side of the wound body formed by the winding is selectively loosened to suppress inconvenient phenomena due to the stepped portion.・ Because it is reduced, it is possible to obtain a cylindrical wound electrode that is densely wound, has a small outer diameter, and can easily achieve a high capacity with a high yield. As a result, a highly reliable secondary battery Greatly contribute to the provision of
[0026]
According to the second aspect of the present invention, it is possible to provide a cylindrical wound electrode that is densely wound, has a small outer diameter, and can easily achieve a high capacity with a high yield.
[Brief description of the drawings]
FIG. 1 is a plan view showing a structural example of a main part of a wound electrode manufacturing apparatus according to the present invention.
FIG. 2 is a cross-sectional view schematically showing a part of the lamination / winding state at the final stage of lamination / winding in the manufacturing process of the wound electrode.
FIG. 3 is a plan view showing a main structure of a conventional wound electrode manufacturing apparatus.
[Explanation of symbols]
1,7 …… Winding mechanism body
1a, 7a ...... Cores 2, 9 ... Strip-shaped positive electrode sheets 3, 8 ... Strip-shaped negative electrode sheets 4, 4 ', 10, 10' ... Interlayer insulating sheets 5, 11 ... Guide mechanism
6a, 6b, 13a, 13b …… Pressure roller
12a, 12b …… Cylindrical electrode holding block
14a, 14b …… Air cylinder
15a, 15b …… Pressure adjustment mechanism

Claims (2)

A winding step of laminating and winding the belt-like positive electrode sheet, the interlayer insulating sheet, the negative electrode sheet and the interlayer insulating sheet on the winding core;
A pressing step of pressing the outer peripheral surface of the cylindrical electrode wound around the core body in a diametrical direction and pressing with a rotary pressure roller at a substantially constant pressure, and
In the pressing step, at the final stage when the winding of the positive electrode sheet is finished, the cylindrical electrode outer peripheral surface is pressed with a pressure smaller than the constant pressure. . A winding mechanism main body having a winding core body in which a belt-like positive electrode sheet, an interlayer insulating sheet, a negative electrode sheet and an interlayer insulating sheet are laminated and wound in a spiral shape;
Cylindrical electric holding having a plurality of divided facing surfaces that are arranged concentrically and opposed to the winding core and hold the outer peripheral surface of the cylindrical electrode that is wound and has an arc that is a half cylinder or less. Block,
A plurality of pressure rollers arranged so as to be movable back and forth between the cylindrical electrode holding blocks, and pressed oppositely in the diametrical direction corresponding to the cylindrical electrodes wound around the winding core;
Pressure capable of adjusting the pressure with the pressure roller, and reducing the pressure with the pressure roller from the previous pressure at the final winding stage after the positive electrode sheet has been wound. A winding type electrode manufacturing apparatus comprising: an adjustment mechanism.

Images