JP2002343342A - Secondary battery electrode and method of manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a safe and reliable secondary battery in which the risk of short circuit between a positive electrode and a negative electrode is reduced and the insulation resistance between the positive electrode and the negative electrode is stabilized, and which is highly reliable. SOLUTION: An electrode for a secondary battery characterized in that a collective electrode 10 is formed from three components of a long negative electrode 3, an insulator 7 and a positive electrode 6 and is bent into a corrugated shape at an arbitrary even number of times, and its manufacture. Provide a way.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrode of, for example, a secondary battery mainly comprising a current collector, a non-ferrous metal electrode, and a polymer insulator, and a method of manufacturing the same.

[0002]

2. Description of the Related Art As a conventional example of a lithium polymer secondary battery mainly composed of a current collector, a non-ferrous metal electrode and a polymer insulator, an electrode configuration shown in FIG. 5 and a manufacturing method shown in FIGS. I have.

As shown in FIG. 5, a conventional secondary battery electrode has a single-plate negative electrode 103 and a porous polymer insulator 107 located on both sides of the negative electrode 103 and having a shape larger than that of the negative electrode 103.
And a single-plate positive electrode 106 located on both sides of the negative electrode 103 and having a shape smaller than that of the negative electrode 103. The component is a pair of electrodes 108 whose respective interfaces are welded and joined. And the desired secondary battery electrode 113
And The negative electrode 103 and the positive electrode 106 have a negative terminal convex portion 153 and a positive terminal convex portion 1 necessary for conductive coupling with an external terminal.
54 are provided at positions where there is no tolerance.

As shown in FIGS. 6 and 7, a conventional method for manufacturing a secondary battery electrode is to form a current collector A102 on the front and back layers of a copper foil 101 obtained by cutting a long part into a comb-like shape 150. Then, a negative electrode 103 was obtained. After the current-collecting material B105 was formed on the front and back layers of the long porous aluminum foil 104, each of them was cut into an arbitrary shape 151 to form a single-plate positive electrode 106.

The single-plate positive electrode 106 is bonded to the front and rear surfaces of the long negative electrode 103 with relatively long precision via an insulator 107 made of a long porous polymer.
Insulator 107, negative electrode 103, insulator 107, positive electrode 106
Were laminated.

The long negative electrode 103 and the long insulator 10
7 was controlled at about 80 ° C. as shown in FIG.
The welding was continuously performed by heating the pair of heating rolls 90 while rotating them in the I direction at a speed of 2 to 3 m / min. Thereafter, the positive electrode 106 was sandwiched from both sides and welded by two pairs of heating blocks 111 controlled at about 80 ° C. to obtain the above-described configuration. One stack of electrodes 108 was cut off from the end of the long electrode configured as described above.

Further, the electrodes 108 of one stack are stacked in an arbitrary number and bound and fixed with a tape 155 or the like.
The secondary battery electrode 113 of the cell was used. Here, in the bonding, a roll welding means 109 for continuously bonding the negative electrode 103 and the insulator 107, a shape positioning means 110 for bonding with relatively high accuracy, and a planar heating for uniform bonding. A method for manufacturing an electrode of a secondary battery including welding means 112 and high-precision cutting means 113 for suppressing the occurrence of burrs was used for the cutout.

[0008]

In the electrode of a secondary battery, it is most preferable to manufacture the electrode at a low cost with a quality that prevents a short circuit between the positive electrode and the negative electrode, stabilizes the insulation resistance between the current collector and the insulator. is important. However, the conventional secondary battery electrode configuration requires positioning, bonding, cutting, and bundling of terminals according to the number of components, resulting in increased risk of contact between electrodes and the incorporation of metal foreign matter, resulting in short-circuiting and insulation resistance. It is expected that the quality involved will be significantly impaired. For example, the number of components required to make a single-stack electrode composed of five components into an electrode configuration of five cells in a five-stack configuration is 25, making it difficult to supply a safe and reliable battery at low cost. it was thought. In addition, since the external dimensions and the coupling position with the external terminal are determined by the electrode shape, it is extremely difficult to expand the variety.

The present invention significantly reduces the number of parts to mitigate the above-mentioned danger, and provides a secondary battery electrode having an extremely simple structure and a method of manufacturing the secondary battery electrode. The purpose is to supply inexpensively.
It is another object of the present invention to increase the commercial value of a secondary battery by supplying a secondary battery electrode that can flexibly select a size, the number of stacked products, and a coupling position with an external terminal.

[0010]

In order to achieve the above object, the present invention is configured as follows.

According to the first aspect of the present invention, the negative electrode having the current collector A on one of the front and back layers of the long copper foil and the current collector B
Is provided between the positive electrode having one of the front and back layers of the long aluminum foil, a long porous polymer insulator is provided, and the negative electrode, the positive electrode and the insulator are thermally welded to form a collective electrode, Provided is an electrode for a secondary battery, wherein the electrode is bent into a corrugated shape an arbitrary number of times. Further, the present invention provides an electrode for a secondary battery, wherein a current collecting material at the top of a collective electrode folded in a corrugated shape is peeled at an arbitrary length and width in a short side direction.

Further, the present invention provides an electrode for a secondary battery, wherein the current collector at the end of the negative electrode and the current collector at the end of the positive electrode are peeled into an arbitrary shape.

According to a second aspect of the present invention, there is provided a heat-welded portion which continuously heat-welds a negative electrode, a positive electrode and an insulator to form a collective electrode; Part, a first peeling part for peeling the current collecting material on the top of the collecting electrode at an arbitrary length and width in the short side direction,
A method for manufacturing an electrode for a secondary battery, comprising: a second peeling portion configured to peel off a current collector at an end of a negative electrode and an end of a positive electrode of the collective electrode into an arbitrary shape.

Further, the present invention provides a method for manufacturing an electrode of a secondary battery, wherein two pairs of induction heating rolls are used in the heat welding portion.

Further, the present invention provides a method for manufacturing an electrode of a secondary battery, wherein a semiconductor laser is used in a part where the current collector is peeled off.

[0016]

Embodiments of the present invention will be described below in detail with reference to the drawings.

An electrode of, for example, a polymer secondary battery and a method of manufacturing the same in one embodiment of the present invention will be described below with reference to FIGS. In the drawings, the same components are denoted by the same reference numerals.

As shown in FIG. 2, the electrode of the secondary battery according to the present embodiment and the method for manufacturing the same are as follows. First, a current collector 2 having a thickness of 100 μm is attached to one surface of a long copper foil 1 having a thickness of 15 to 20 μm. The negative electrode 3, a positive electrode 6 in which a current collector 5 having a thickness of 100 μm is adhered to one surface of a long aluminum foil 4 having a thickness of 15 to 20 μm, and a long porous polymer insulator 7 having a thickness of 10 to 30 μm are prepared. . It is desirable that the thickness of each layer be controlled to 10% or less because the thickness affects battery performance. In particular, since both ends tend to have large dimensional variations, sufficient management is required (not described in detail). Fine holes 8 for accelerating the permeation of the electrolyte may be formed in one or both of the long copper foil 1 and the aluminum foil 4. On the other hand, the insulator 7 was sandwiched between the negative electrode 3 and the positive electrode 6 and the temperature was controlled at about 80 ° C. from the surface H side of the negative electrode 3 and the positive electrode 6 as shown in FIG.
The pair of induction heating rolls 9 is heated while rotating in the I direction at a speed of 2 to 3 m / min, and the negative electrode 3, the insulator 7 and the positive electrode 6 are continuously thermally welded to form the collective electrode 10. According to this method, there is an advantage that the welding temperature distribution is made uniform by the induction heating and the insulation resistance value is secured safely.

Here, the long width direction is set to be approximately the width of one battery electrode, and the long direction is also set to be the length of one battery electrode. Will be described assuming a continuous band. At this time, there is a means for cutting into a predetermined length, which will be described later.

Next, the collective electrode 10 thus formed is
It is put into a corrugated molding section 12 composed of two pairs of corrugated rolls 11 and continuously bent into a corrugated shape K at an arbitrary even number of times while rotating in the J direction at a speed of 2 to 3 m / min. The outer circumferential portion m of the two pairs of corrugated rolls 11 is provided with a convex portion 13 and a concave portion 14 having a shape and height theoretically calculated by a distance L corresponding to the bending length. At this time, the corrugation angle α can be changed by minutely changing the biting depth N of the protrusion 13 into the recess 14, but at this time, the corrugation angle α is relatively large, and the compression force P1 The corrugation angle α can be sequentially reduced to α1 to α3 by adding ＰP3. However, the electrode bent here is in a state of relatively loose adhesion. This is because, in the method of inserting the secondary battery electrode of the present invention into, for example, a case and injecting the electrolytic solution (not described in detail), the diffusion of the electrolytic solution into the current collector 2, the current collector 5, and the insulator 7 is performed. Since the permeation can be made uniform in a short time, there is an advantage that the battery characteristics are improved and stabilized.

Further, if it is folded into a corrugated shape even number of times, both the surface of the negative electrode 3 and the surface of the positive electrode 6 are always outward, so that there is an advantage that the positive and negative electrode terminals (described later) can be drawn out at arbitrary positions.

In order to process the corrugated shape K in conjunction with the welding speed, it is necessary to intermittently rotate the induction heating roll 9 in the direction I. However, when the induction heating roll 9 is stopped, heat concentrates on the processing target portion and the insulator 7
Since there is a danger of melting, etc., a slack R is provided in the longitudinal direction to serve as a buffer so as not to stop.

As a means for alleviating the bending load, a method of peeling off the current collecting material 2 or 5 before heat welding or partially dissolving and removing the collective electrode 10 before putting it into the corrugated molded portion 12 is adopted. May be used. For example, the laser light 21 of the laser head 20 is scanned in the width direction O of the collective electrode 10 at a pitch of L dimension corresponding to the size of the electrode, and the current collector is separated in the short side direction. At this time, if the output of the laser is intermittently turned ON / OFF, the laser can be peeled at an arbitrary length and width. According to experiments, the output of the laser is 1200 w to 4000 w at the maximum, and the output can be easily selected according to the peeling level and the dissolution level. Since the dissolved slag is generated when the current collector is peeled off, a suction unit is provided at a position facing the blow unit based on a logical calculation or an experiment (not shown).

In order to perform the laser processing in conjunction with the welding speed, it is necessary to intermittently rotate the induction heating roll 9 in the direction I. However, when the induction heating roll 9 is stopped, heat is concentrated on the processing target portion, and there is a risk that the insulator 7 is melted.
And make a buffer so that it does not stop.

As a means for cutting the band-shaped collective electrode 10 into a predetermined length, a method of melting and cutting the collective electrode 10 before bending the corrugated portion 12 is used. For example, the collective electrode 10 is several times the pitch of the L dimension corresponding to the size of the electrode.
The laser beam 21 of the laser head 20 is scanned in the width direction O of FIG. At this time, it is possible to cut the laser at an arbitrary length in the longitudinal direction by controlling ON / OFF of the output of the laser. According to experiments, the maximum laser output is 3000 w to 4000 w, and the output can be easily selected according to the melting and cutting level. Since melting slag is generated in the melting and cutting, a suction unit is provided at a position facing the blow unit based on a logical calculation or an experiment (not shown).

In order to perform the laser processing in conjunction with the welding speed, it is necessary to intermittently rotate the induction heating roll 9 in the direction I. However, when the induction heating roll 9 is stopped, the heat is concentrated on the processing target portion, and there is a danger that the insulator 7 is melted.
And make a buffer so that it does not stop.

The secondary battery electrode 15 is formed by combining the above means.

Next, the electrode terminal 30 is connected to the copper foil 1 of the negative electrode 3 and the aluminum foil 4 of the positive electrode 6 by means of conduction with the outside of the collective electrode 10 (the connection means is not described in detail). When it is necessary to remove the high current collecting material in advance, the laser beam 21 of the laser head 20 is continuously scanned as shown in FIG. 3, and for example, as shown in FIG. When the current collector 2 is formed on the surface and the current collector 5 is formed on the surface of the aluminum foil 4 of the positive electrode 6, the current collector is peeled off. The current collecting material of each of the negative electrode 3 and the positive electrode 6 is peeled off in an area of S dimension corresponding to the size of the electrode terminal or more. At this time, it is possible to peel off an arbitrary area by controlling ON / OFF of the laser output. According to experiments, the maximum laser output is about 1200 watts, and the output can be easily selected according to the peeling level. Since the dissolved slag is generated when the current-collecting material is separated, a blow portion is provided at a position facing the blow portion based on calculations and experiments (not shown).

In order to perform the laser processing in conjunction with the welding speed, it is necessary to intermittently rotate the induction heating roll 9 in the direction I. However, when the induction heating roll 9 is stopped, there is a danger that the insulator 7 is melted due to heating and concentration on the portion to be processed. Therefore, a slack R is provided in the longitudinal direction to provide a buffer so as not to stop.

In this embodiment, it is assumed that the current collector is formed on one inner surface of the negative electrode 3 and the positive electrode 6, but it is assumed that the fine holes 8 are formed in the copper foil 1 or the aluminum foil 2 as described above. Then, when the current collector is formed, the current collector leaks into the surface layer through the fine holes 8, and it is assumed that the current collector having a high insulation resistance may make it difficult to bond the electrode terminals 30. Therefore, it is also effective when it is necessary to remove the current collector in advance.

By using the above-described manufacturing method, as shown in FIG. 4, a corrugated secondary having an even number of times and a bent length L composed of three parts of a negative electrode 3, an insulator 7 and a positive electrode 6 is provided. The battery electrode 15a can be obtained. The electrode terminal 30 can be installed at any position in the secondary battery electrode 15a. Further, the secondary battery electrode 15 in which the current collecting material on the top of the collecting electrode is peeled off in an arbitrary length and width in the short side direction to be easily bent.
For example, when a current collector is formed on both sides of the electrode b or the electrode plate, the secondary battery electrode 15c in which the terminal current collector is peeled off in an arbitrary shape can be obtained as necessary.

[0032]

As described above in detail, according to the electrode of the secondary battery of the present invention and the method of manufacturing the same, the temperature distribution is made uniform by the induction heating welding to form the collective electrode, so that the insulation resistance value is stabilized. Can be secured. In addition, since the number of parts is three (1/8 times that of the conventional method), it is possible to reduce the risk of dust being mixed in and short circuit between the positive electrode and the negative electrode. Further, the number of processing steps can be significantly reduced. In addition, by adopting the corrugated shape, the diffusion and penetration of the electrolytic solution can be made uniform in a short time, and the battery characteristics can be improved and stabilized. In addition, the positive and negative terminals can be pulled out at any positions. In addition, the degree of freedom can be given to the size of the electrode and the position where the terminal is taken out by applying the laser processing. As described above, there is an effect that a safe and highly reliable secondary battery is supplied at a low cost.

Further, the secondary battery electrode which can flexibly select the size, the number of stacked products, and the coupling position with the external terminal has the effect of increasing the commercial value of the secondary battery.

[Brief description of the drawings]

FIG. 1A is a flowchart of a method for manufacturing a secondary battery electrode according to one embodiment of the present invention; FIG. 1B is a schematic diagram of corrugated molding according to one embodiment of the present invention;

FIG. 2A is a diagram of a secondary battery electrode structure according to an embodiment of the present invention; FIG. 2B is a detailed diagram of a secondary battery electrode structure according to an embodiment of the present invention;

3A is a schematic view of a film peeling means of a secondary battery electrode according to one embodiment of the present invention; FIG. 3B is a schematic view of a film peeling means of a secondary battery electrode according to another embodiment of the present invention;

FIG. 4 is a schematic diagram of a secondary battery electrode according to the present invention.

FIG. 5 is a schematic view of a conventional secondary battery electrode.

6 (a) is a flow chart of a conventional method for manufacturing a secondary battery electrode, and FIG. 6 (b) is a flow chart of a conventional method for manufacturing a secondary battery electrode. FIG. 6 (c) is a flow chart of a conventional method for manufacturing a secondary battery electrode. Positive and negative electrode lamination diagram

FIG. 7 is a flowchart of a conventional method for manufacturing a secondary battery electrode.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Copper foil 2 Current collector A 3 Negative electrode 4 Aluminum foil 5 Current collector B 6 Positive electrode 7 Insulator 9 Induction heating roll 10 Collecting electrode 11 Corrugate roll 12 Corrugation forming part 15 Secondary battery electrode 20 Laser head 21 Laser beam 30 Electrode Terminal 90 Heating roll 101 Copper foil 102 Current collector A 103 Negative electrode 104 Aluminum foil 105 Current collector B 106 Positive electrode 107 Insulator 108 Electrode 111 Heating block 113 Secondary battery electrode 153 Negative terminal 154 Positive terminal 155 Tape

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5H050 AA07 AA15 AA19 BA08 DA01 DA13 DA19 EA23 FA02 FA06 GA02 GA03 GA04 GA07 GA08 GA29 HA12

Claims (6)

[Claims] 1. A long electrode is provided between a negative electrode having a current collector A on one of the front and back layers of a long copper foil and a positive electrode having a current collector B on one of the front and back layers of a long aluminum foil. Secondary battery, wherein the porous polymer insulator is provided, the negative electrode, the insulator, and the positive electrode are thermally welded to form a collective electrode, and the collective electrode is bent into a corrugated shape at an arbitrary even number of times. electrode. 2. The secondary battery electrode according to claim 1, wherein the current-collecting material at the top of the collective electrode bent in a corrugated shape is peeled off at an arbitrary length and width in a short side direction. 3. The secondary battery electrode according to claim 1, wherein the current collector at the terminal of the negative electrode and the current collector at the terminal of the positive electrode are peeled into an arbitrary shape. 4. A heat welding step in which a negative electrode, a positive electrode, and an insulator are successively heat-welded to form a collective electrode; A first peeling step of peeling the current-collecting material at an arbitrary length and width in the short side direction, and a second peeling step of peeling the current-collecting material at the end of the negative electrode and the end of the positive electrode of the collective electrode into an arbitrary shape, A method for manufacturing a secondary battery electrode, comprising: 5. The method for manufacturing a secondary battery electrode according to claim 4, wherein two pairs of induction heating rolls are used for the heat welding portion. 6. The method for manufacturing a secondary battery electrode according to claim 4, wherein a semiconductor laser is used in a portion where the current collector is separated.