JPH11339844A - Manufacture of wound electrode - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high-yield manufacturing method of a highly reliable wound electrode (an electromotive portion) which has high capacity resulting from tight rolling. SOLUTION: In a manufacturing method of a wound electrode in which a positive electrodes sheet 2 and a negative electrode sheet 3 spirally roll around a rotating core 1 and insulating sheet between layers 4 and 4' are interposed therebetween while applying tension to the positive electrode sheet 2 and the negative electrode sheet 3, the frequency of the core 1 rotation is set and changed to reduce at the final stage of the rolling. One example of the positive electrode sheet 2 and the negative electrode sheet 3 is an electrode sheet for a nickel hydrogen battery.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for manufacturing a wound electrode, and more particularly, to a method for manufacturing a highly reliable wound electrode with a high yield.

[0002]

2. Description of the Related Art In recent years, as electronic devices such as portable telephones and portable notebook computers have become cordless, have higher performance, and have been made smaller and lighter, the capacity of batteries used as power sources for these electronic devices has increased. Is required. As a battery serving as a power source, a nickel-hydrogen secondary battery capable of achieving high capacity has been put into practical use in place of a conventionally used lead storage battery or nickel-cadmium battery.

In general, this type of secondary battery has a wound type electrode (electromotive force) formed by inserting an interlayer insulating sheet between a positive electrode sheet and a negative electrode sheet and winding the laminate. Is sealed in a liquid-tight manner together with a predetermined amount of electrolyte in a battery outer container. In the case of a cylindrical battery, the wound electrode is usually sandwiched between a band-shaped separator (sheet for interlayer insulation) by a pair of core rods (core bodies) having a semi-cylindrical portion. After the belt-shaped positive electrode sheet and the band-shaped negative electrode sheet are separately positioned and positioned, the core is wound in a spiral shape by rotating a core (core rod) at a predetermined speed.

FIG. 3 schematically shows an embodiment of manufacturing a wound electrode. Here, reference numeral 1 denotes a rotatably mounted core that spirally winds the strip-shaped positive electrode sheet 2, the strip-shaped negative electrode sheet 3, and the strip-shaped interlayer insulating sheets 4, 4 '. 5a and 5b are the rotating core 1
, And each sheet 2, 3, 4, which is spirally wound
This is a pressure roller for applying a required tension to the 4 '. Here, the pressing rollers 5a and 5b are configured as a retractable type that presses the outer peripheral surface of the winding to form a dense wound body, and a pressure adjusting (pressure changeable) type.

Further, reference numerals 6a and 6b denote electrode holding blocks which sandwich and hold the outer peripheral surface of the wound body wound and formed on the core body 1, and are installed so as to be opposed to each other and advance and retreat. In addition,
The core body 1 is provided with a semi-cylindrical section in cross section that forms opposed flat surface portions so that a continuous portion of the interlayer insulating sheets 4 and 4 ′ can be sandwiched.

[0006] In the production of the wound electrode, first, an interlayer insulating sheet (separator) 4 is provided between opposing flat surfaces of the core 1.
4 'is continued. Then, while positioning the positive electrode sheet 2 on the interlayer insulating sheet 4 and positioning the negative electrode sheet 3 on the interlayer insulating sheet 4 ′ and feeding them along the shape, the core 1 is rotated at a predetermined speed. Get involved by driving.

Here, while the sheets 2, 3, 4, and 4 'are spirally wound around the core 1, the outer peripheral surface of the spiral formed is maintained at a constant pressure by the pressing rollers 5a and 5b. Pressurization (pressing) or tension is applied to form a wound electrode (electromotive portion) that is densely wound. At this time, the advance and retreat and pressurization of the pressure rollers 5a and 5b are performed by the corresponding air cylinders 5a 'and 5b'.

Thereafter, while the rotation and the driving of the core 1 are stopped, the supplied sheets 2, 3, 4, and 4 'are cut off from a supply / rewind roller (not shown) side and disposed so as to be able to advance and retreat. The pair of electrode holding blocks 6a and 6b
The wound electrode is obtained by holding and holding the outer peripheral surface of the wound and formed wound electrode, pulling out the wound core body 1 and separating them. The spiral winding is performed at a constant rotation speed (constant rotation speed) of the core 1 from the start to the end of the winding.

[0009]

However, the conventional method of manufacturing a wound electrode 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-metal hydride secondary battery increase. Conversely, the interlayer insulating sheet 4,
While 4 'is made thinner, a more dense spiral lamination and winding is required. And, with the dense winding,
In the method of manufacturing a wound electrode, the electrode holding block 6
Due to the contact between a and 6b, the interlayer insulating sheets 4 and 4 'are liable to be rubbed and broken, and a tendency to cause a short circuit between the positive electrode sheet and the negative electrode sheet is recognized.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and not only achieves a high capacity by dense winding but also provides a highly reliable wound electrode with a good yield. For the purpose of providing.

[0011]

According to a first aspect of the present invention, there is provided a winding type in which a positive electrode sheet and a negative electrode sheet are tensioned by interposing an interlayer insulating sheet and spirally wound around a rotating core body. A method of manufacturing an electrode, wherein the number of revolutions of a core is set or changed to be low at the end of the winding.

According to a second aspect of the present invention, in the method for manufacturing a wound electrode according to the first aspect, the positive electrode sheet and the negative electrode sheet are electrode sheets for a nickel-metal hydride battery. That is, according to the first and second aspects of the present invention, when each of the sheets for forming the wound electrode is spirally wound around the core, the electrode sheet is wound at a substantially constant (or predetermined) rotational speed. In the termination stage (winding termination process), the number of rotations (or rotation speed) of the core is reduced, and the tension applied to the interlayer insulating sheet and the like is reduced.
The essence is to avoid frictional damage and the like of the densely wound outer peripheral surface. In other words, in the production of a wound electrode in which each sheet for forming a wound electrode is rotated in a spiral manner, the interlayer insulating sheet is liable to cause friction damage in the production of the wound electrode, specifically, At the time when the diameter of the wound body is large and it is easy to make sliding contact with the electrode holding block (end of winding),
On the other hand, while the sliding contact is relaxed to achieve a fine winding, the short circuit between the electrode sheets is eliminated and avoided.

According to the first and second aspects of the present invention, a high-performance, compact, lightweight, highly reliable wound electrode capable of achieving high capacity by dense winding and eliminating the possibility of short-circuiting. Is easily provided.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 (a), (b) and FIG.
An example will be described with reference to FIG.

This embodiment is an example of manufacturing a wound electrode for a nickel-hydrogen secondary battery. The embodiment is basically the same as the conventional case, and will be described with reference to FIG. That is, as shown in FIG.
An interlayer insulating sheet (separator) having both ends wound by a rewind roller (not shown) is sandwiched between opposed flat surfaces of the core 1, and one side of the interlayer insulating sheet 4
And the negative electrode sheet 3 is positioned along the interlayer insulating sheet 4 'on the other side. On the other hand, the core 1 is rotated and driven at a predetermined speed (at the number of rotations), and the pressure rollers 5a and 5b
The sheet is wound by applying a pressure of about 0.5 to 1.5 kgf / cm ² (with tension applied to the sheets 2, 3, 4, and 4 '). Here, the interlayer insulating sheets (separators) 4, 4 'are, for example, 0.2 mm in thickness and 63 mm in width, the positive electrode sheet 2 is, for example, 0.6 mm in thickness, 60 mm in width, and the negative electrode sheet 3 is, for example,
0.3mm, width 60mm.

FIG. 1A shows that each of the sheets 2, 3,
It is a top view which shows typically the state of the winding completion stage (final winding process) which winds 4, 4 'and forms a wound type electrode. That is, each sheet 2, 3, 4, as a body to be wound
With the tension applied to the 4 ', the core 1 is rotated and driven at a predetermined number of revolutions, and when approaching the point where the winding of the wound electrode is completed, the number of revolutions of the core 1 decreases. Or switched to low speed and spin. Therefore, for example, the electrode sheet 2 and the insulating separator 4 are cut off 210 ° before the winding is completed, and even if one of the electrode holding blocks 6b presses the outer peripheral surface of the wound wound electrode, The friction with the outer peripheral surface of the wound electrode rotating at the time is small, so that the insulating separators 4 and 4 ′ on the outer peripheral surface of the wound electrode are damaged by friction, furthermore, the dielectric breakdown between the electrode sheets 2 and 3 and the electrode Damage to the sheets 2 and 3 themselves is also avoided.

FIG. 1 (b) shows that each of the sheets 2, 3,
It is a top view which shows typically the state at the time of completion | finish of winding which wound 4 and 4 'and formed the wound type electrode. That is, the wound electrode (winding body 1) whose outer peripheral surface is pressed by one of the electrode holding blocks 6b at 210 ° before the end of the above winding is further rotated by 210 ° at a low speed to finish the winding process. And
At the same time when the electrode sheet 3 and the insulating separator 4 'are separated, the outer peripheral surface of the wound electrode is pressed by the other electrode holding block 6a, and as a result, the wound electrode is sandwiched by the electrode holding blocks 6a and 6b. Hold. Also at this stage, since the formed wound electrode rotates at a low speed, frictional damage of the insulating separators 4, 4 'on the outer peripheral surface side of the wound electrode, and furthermore,
The risk of dielectric breakdown between the electrode sheets 2 and 3 and damage to the electrode sheets 2 and 3 themselves is also eliminated.

FIG. 2 shows an example of the relationship between the number of rotations from the start of the rotation driving to the end of the rotation of the winding core 1 in the step of forming the winding of the wound electrode. Until (1 to 2.0 times before the end), wind at a high speed rotation of 10 rps or more, and thereafter (1 to 2.0 times immediately before the end) 10 rps
Wind at a low speed of less than.

The present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the invention. For example, the thickness and width of the insulating sheet, the positive electrode sheet, and the negative electrode sheet can be appropriately set in accordance with the type and capacity of the target secondary battery.

[0020]

According to the first and second aspects of the present invention, not only a high capacity can be achieved by dense winding, but also a high-performance wound electrode in which occurrence of a short circuit in an electrode sheet is eliminated. Can be easily provided. That is, higher performance of the battery,
Since a high-quality wound electrode suitable for miniaturization and weight reduction can be provided with high yield, it greatly contributes to practical use of a high-capacity, compact battery desired as a power source for cordless electronic devices.

[Brief description of the drawings]

FIGS. 1 (a) and 1 (b) are schematic diagrams showing a winding end stage in a manufacturing process of a wound electrode according to an embodiment and an operation state of an electrode holding block with respect to the wound electrode at the end of winding. FIG.

FIG. 2 is a curve diagram showing a change in rotation speed change during winding rotation of a core in a manufacturing process of a wound electrode according to an example.

FIG. 3 is a top view schematically showing an initial state of lamination and winding of each sheet in an example of a manufacturing process of a wound electrode.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Winding core 2 ... Strip-shaped positive electrode sheet 3 ... Strip-shaped negative electrode sheet 4, 4 '... Interlayer insulating sheet 5a, 5b ... Pressure roller 5a', 5b '... Air cylinder 6a, 6b …… Electrode holding block

Claims (2)

[Claims] 1. A method of manufacturing a wound electrode in which a positive electrode sheet and a negative electrode sheet are inserted in an interlayer insulating sheet and spirally wound around a rotating core while applying tension to the positive electrode sheet and the negative electrode sheet, A method of manufacturing a wound electrode, wherein the number of revolutions of a body is reduced at a winding end stage. 2. The method for producing a wound electrode according to claim 1, wherein the positive electrode sheet and the negative electrode sheet are electrode sheets for a nickel-metal hydride battery.