JPH09213341A - Base plate for battery electrode and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a base plate for battery electrode in which a black mix of active material permeates well and there is no fear of slipping off, by forming a mat-shaped non-woven cloth from metal fibers having a specific porosity, and sewing together a plurality of cloth pieces with threads so that they are precluded from untying. SOLUTION: From metal fibers (aluminum or copper), a mat-shaped non- woven cloth 2, having a porosity of 50-98% is fabricated by a random weaver or the like. A plurality of non-woven cloth pieces 2 are sewn together using threads 3 of nylon fiber, etc., so that they do not untie, and thereby a base plate 1 for battery electrode is fabricated. Because a black mix of active material for battery permeates well into the material, it involves no fear of slipping off and sustains a bending stress, so that a base plate for positive electrode or negative electrode of high capacity can easily be obtained.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to improvement of an electrode substrate for a battery.

[0002]

2. Description of the Related Art FIG. 7 is a structural principle diagram of a cylindrical lithium secondary battery. A cylindrical lithium secondary battery 100 includes a positive electrode substrate 102 having a positive electrode lead 101 and a separator 10.
3 and the negative electrode substrate 105 having the negative electrode lead 104 stacked in this order are further spiral-shaped to form a battery case 107.
And is sealed with a sealing plate 109 via an insulating packing 108. The positive electrode substrate 102 is generally formed by mixing a positive electrode active material mixture with a binder to form a paste, applying the paste to an aluminum foil, and drying the paste. The negative electrode substrate 105 is generally used by mixing a negative electrode active material mixture with a binder to form a paste, coating the paste on a copper foil, and drying the paste.

[0003]

Since the performance of the battery depends on the filling amounts of the positive electrode active material mixture and the negative electrode active material mixture, both the positive electrode active material mixture and the negative electrode active material mixture are thickened. Need to paint. However, it is difficult to apply a large amount of paste to the positive electrode substrate 102 at one time because the surface of the aluminum foil is flat, and the coating and drying must be repeated several times to increase the film thickness and the bonding force. Since it is weak, the positive electrode active material mixture may peel off and fall off when it is bent to be incorporated in a battery case, and it is difficult to increase the film thickness.

Similarly, since the surface of the copper foil is flat on the negative electrode substrate 105, it is difficult to apply a large amount of paste at once, and the application and drying must be repeated several times to increase the film thickness. In addition, since the bonding strength is weak, the negative electrode active material mixture may peel off and fall off when it is bent to be incorporated in a battery case, and it is difficult to increase the film thickness. That is, since a metal foil with a smooth surface is conventionally used for both the positive electrode / negative electrode substrates, there is a limit to the amount of the active material mixture that can be applied, and if the active material mixture falls off when assembled into a battery. There was a problem to say.

[0005]

Means for Solving the Problems The inventors of the present invention have focused on fine metal fibers while searching for an alternative technique to the conventional technique of applying a paste to a metal foil. That is, when the metal fibers are formed into a sheet and the paste is applied to the sheet, the paste easily permeates between the metal fibers, and the adhesiveness is remarkably improved. However, since it is an aggregate of metal fibers, it has the disadvantage of "raveling". Furthermore, through repeated research, we succeeded in developing a technology that can overcome fraying.

Specifically, the battery electrode substrate according to claim 1 is characterized in that it has a porosity of 50 to 98% and a mat-like nonwoven fabric of metal fibers is sewn with a thread to prevent fraying. And The type of thread differs depending on the active material mixture for the battery, but for battery component materials (active material agents, etc.) such as nylon fiber thread, synthetic fiber thread such as polyester fiber thread or carbon fiber thread, and glass fiber thread. Inert ones are preferred. Since the positive electrode active material mixture and the negative electrode active material mixture permeate well into the mat-like nonwoven fabric, there is no risk of the positive electrode active material and the negative electrode active material mixture falling off. Since the whole is sewn with an inert thread, there is no problem such as a side reaction (generation of a local battery) when assembled in a battery. Therefore, it is possible to easily provide a high-capacity positive electrode substrate and a high-capacity negative electrode substrate that are resistant to bending.

The battery electrode substrate according to claim 2 has a porosity of 5
It is characterized in that it is 0 to 98% and is made by attaching a metal foil to one or both sides of a mat-like non-woven fabric of metal fibers and sewing the whole with thread to prevent fraying. Since the positive electrode active material mixture paste and the negative electrode active material mixture paste permeate well into the composite mat-like non-woven fabric with the metal foil, there is no risk of the positive electrode active material and negative electrode active material mixture falling off. Since the whole is sewn with an inert thread, there is no problem such as a side reaction (generation of a local battery) when assembled in a battery. Therefore, it is possible to easily provide a high-capacity positive electrode substrate and a high-capacity negative electrode substrate that are resistant to bending.

The battery electrode substrate according to claim 3 has a porosity of 5
It is characterized in that it is 0 to 98% and the mat-like non-woven fabric of metal fibers is entirely fray-prevented by the needle punching method. Since the positive electrode active material mixture paste and the negative electrode active material mixture paste permeate well into the composite mat-like non-woven fabric with the metal foil, there is no risk of the positive electrode active material and negative electrode active material mixture falling off. Since the whole is connected by a needle loop, there is no problem such as side reaction (generation of local battery) when assembled in a battery.
Therefore, it is possible to easily provide a high-capacity positive electrode substrate and a high-capacity negative electrode substrate that are resistant to bending.

A fourth aspect of the invention is characterized in that the metal fiber is aluminum or copper. Since easily available aluminum or copper is used, the cost of the electrode substrate can be reduced.

According to a fifth aspect of the present invention, there is provided a step of rolling down the mat-shaped nonwoven fabric made of metal fibers with the first roller to increase the density, a stitching step of sewing the rolled mat-shaped nonwoven fabric with a sewing machine, and a second roller. This is a method of manufacturing a battery electrode substrate, which comprises a finishing step of flattening the upper and lower surfaces of the electrode substrate.

According to a sixth aspect of the present invention, there is provided a step of rolling down the mat-shaped nonwoven fabric of metal fibers with a first roller to increase the density, and a stitching step of sewing the rolled down mat-shaped nonwoven fabric with a needle punch machine. This is a method for manufacturing a battery electrode substrate, which comprises a finishing process in which the upper and lower surfaces are flattened by two rollers, and a large number of electrode substrates can be produced inexpensively.

[0012]

Embodiments of the present invention will be described below with reference to the accompanying drawings. In addition, this embodiment is referred to as “first
.., ", and in the examples in the next section, they are distinguished by expressing them as" Example 1, Example 2 ... ". FIG. 1 is an enlarged cross-sectional view of a battery electrode substrate according to a first embodiment of the present invention. The battery electrode substrate 1 does not separate the mat-shaped nonwoven fabric 2 of metal fibers from the mat-shaped nonwoven fabric 2. The sewing threads 3 to be sewn together (... indicates a plurality, the same applies hereinafter).

The metal fibers in this example and the following examples are electrode substrate materials, and aluminum (containing aluminum alloy) or copper (containing copper alloy), which is inexpensive and easily available, is suitable. Further, the non-woven fabric of metal fibers is a non-woven fabric (web) of fine fibers of an electrode substrate material such as aluminum and copper by a random webber machine or a card machine. Further, the metal foil is a thin plate of aluminum and copper having a thickness of about 120 μm.

FIG. 2 is an enlarged cross-sectional view of the battery electrode substrate according to the second embodiment of the present invention. The battery electrode substrate 10 is a mat-shaped nonwoven fabric 11 of metal fibers and this mat-shaped nonwoven fabric 1
It is composed of a metal foil 12 which is covered only on one side, and a sewing thread 13 for sewing these.

FIG. 3 is an enlarged cross-sectional view of a battery electrode substrate according to a third embodiment of the present invention. The battery electrode substrate 20 is a mat-shaped nonwoven fabric 21 of metal fibers and this mat-shaped nonwoven fabric 2
It is composed of metal foils 22, 22 covered on both sides of 1 and a sewing thread 23 for sewing these.

FIG. 4 is an enlarged cross-sectional view of the battery electrode substrate according to the fourth embodiment of the present invention. The battery electrode substrate 30 includes a metallic fiber mat-shaped nonwoven fabric 31 and this mat-shaped nonwoven fabric 3
Needle loop 3 sewn so that 1 is not separated
It consists of 2 ...

A method of manufacturing the battery electrode substrate described above will be described below. FIG. 5 is a manufacturing procedure diagram of the first to third embodiments of the present invention.
The roller 41 is pressed down to make it dense, and then the sewing thread 3 (a synthetic fiber thread such as a nylon fiber thread, a polyester fiber thread or a carbon fiber thread, and a glass fiber thread) is used by using a sewing machine 42 including a sewing needle 43 and a bobbin 44. The whole is sewn up with and finished with the second roller 45. Sewing machine 42
By applying, the unevenness is formed on the upper and lower surfaces, but this unevenness can be eliminated by passing the second roller 45. The completed product is the battery electrode substrate 1 shown in FIG.

Further, in FIG. 5, if the metal foil 12 is attached to one surface of the mat-like nonwoven fabric 11 ... Of the metal fibers and the sewing thread 13 is used and sewn together with the sewing machine 42, the battery electrode substrate 10 shown in FIG. Can be manufactured.

Similarly, in FIG. 5, if the metal foils 22, 22 are attached to both sides of the mat-shaped nonwoven fabric 21 ... Of the metal fibers and the sewing thread 23 is used and sewn with the sewing machine 42, the battery shown in FIG. The electrode substrate for use 20 can be manufactured.

FIG. 6 is a manufacturing procedure diagram of the fourth embodiment of the present invention. The mat-like nonwoven fabric 31 of metal fibers 31 is pressed down by the first roller 41 to make it dense, and then the needle punch machine 46.
After the needle punching process (the process of pulling up the metal fiber with the crochet 47 ... and entwining the fibers with the obtained needle loop 32 ...) Using the crochet needle 47. Finish to a specified thickness with. The needle punching process causes unevenness on the upper and lower surfaces, but this unevenness can be eliminated by passing the second roller 45. The finished product
It is the battery electrode substrate 30 shown in FIG.

[0021]

EXAMPLES Examples of the present invention will be described below, but the present invention is not limited thereto. Examples 1 to 8; Material of web (made of mat-shaped non-woven fabric of metal fibers), presence / absence of metal foil placed on one side or both sides, and if any, stitching method, porosity and electrode substrate The quality is shown in Table 1.

[0022]

[Table 1]

In addition to Table 1, details of each embodiment will be described below. Example 1; Fiber diameter of about 50μ manufactured by melt spinning method
m, aluminum fibers cards length 100~500mm obtained by introducing a (fibrillating metal fibers, then uniformly sprayed, machine to matted nonwoven), a thickness of about 3 mm, surface density 405 g / m ² An aluminum web (mat) having a porosity of about 95% was first passed through a first roller 41 having a roll gap set to 1.5 mm based on FIG. 5, to a thickness of about 1.5 mm and an areal density of 405 g / m ^2. , Porosity about 90
A flat surface web was obtained in%. This web was sewn into a lattice with a vertical and horizontal pitch of 20 mm by straight stitching with an industrial sewing machine having a stitch length of 5 mm, using polyester fiber yarn (thread number 50) as the upper thread and the lower thread. This is the second with the roll gap set to 1.5 mm
After passing through the roller 45, a (positive electrode) substrate 1 shown in FIG. 1 having a thickness of about 1.5 mm and a porosity of 90%, in which the fibers were not easily entangled with each other and the fibers were not dropped, was obtained.

Example 2; A copper fiber cone having a fiber diameter of about 50 μm and a length of 30 to 100 mm produced by a wire-cutting method was introduced into a random weber machine to obtain a thickness of about 3 mm.
Based on FIG. 5, a copper web having an areal density of 1,345 g / m ² and a porosity of about 95% was first prepared with a roll gap of 1.5 m.
Through the first roller 41 set to m, the thickness is about 1.5m
A web having a flat surface with m, an areal density of 1,345 g / m ² , and a porosity of about 90% was obtained. This web was sewn into a lattice with a vertical and horizontal pitch of 20 mm by straight stitching with an industrial sewing machine having a stitch length of 5 mm, using polyester fiber yarn (thread number 50) as the upper thread and the lower thread. This is the second roller 45 with the roll gap set to 1.5 mm.
Passing through, the fibers are entangled well and there is no drop of fibers,
A (negative electrode) substrate 1 having a thickness shown in FIG. 1 and having a thickness of about 1.5 mm and a porosity of 90% was obtained.

Example 3 The aluminum foil (1
(00 μm) with one-sided adhesive, fibers are well entangled and fibers do not fall off, good electrical conductivity, high strength, thickness of about 1.5 mm, porosity of mat part 90% A (positive electrode) substrate 10 having the form shown in FIG. 2 was obtained.

Example 4; Copper foil (100 μm) in Example 2
Fig. 2 shows that the fibers are well entangled and the fibers do not fall off, the electrical conductivity is good, the strength is about 1.5 mm, and the porosity of the mat part is 90%. A (negative electrode) substrate 10 having the illustrated form was obtained.

Example 5: The aluminum foil (5
(0 μm) with double-sided attachment, the fibers are well entangled and the fibers do not fall off, and the electrical conductivity is good,
A (positive electrode) substrate 20 having a high strength, a thickness of about 1.5 mm, and a porosity of the mat portion of 90% as shown in FIG. 3 was obtained.

Example 6: Copper foil (50 μm) on one side is added to Example 2, and the fibers are well entangled with each other so that the fibers do not fall off, good electrical conductivity, high strength, and thickness. A (negative electrode) substrate 20 having a form shown in FIG. 3 having a porosity of about 90 mm and a matte portion of about 1.5 mm was obtained.

Example 7: An aluminum fiber having a fiber diameter of about 50 μm and a length of 100 to 500 mm produced by a melt spinning method was introduced into a card to obtain a thickness of 3 mm and an areal density of 40.
An aluminum web (mat) having a porosity of about 95% at 5 g / m ² was treated by the needle punching method shown in FIG. First,
First roller 41 with roll gap set to 1.5 mm
Through, a thickness of about 1.5 mm, an areal density of 405 g / m ² ,
A web having a porosity of about 90% and a flat surface was obtained. Crochet 4
Needle punch processing is performed by the needle punch machine 46 in which the pitch of 7 is set to 7 mm, and the roll gap is 1.5 mm.
The fibers are well entangled with each other through the second roller 45 set to 1, and the fibers do not fall off, the thickness is about 1.5 mm, and the porosity is 9
0% of the (positive electrode) substrate 30 shown in FIG. 4 was obtained.

Example 8: A copper fiber cone having a fiber diameter of about 50 μm and a length of 30 to 100 mm produced by a wire-cutting method was introduced into a random weber machine to obtain a thickness of 3 mm and an areal density of 1,345 g / m. ^2. A copper web having a porosity of about 95% was treated by the needle punching method shown in FIG. First, a web having a flat surface with a thickness of about 1.5 mm, an areal density of 1,345 g / m ² , and a porosity of 90% was passed through the first roller 41 with the roll gap set to 1.5 mm. Needle punching is performed by a needle punching machine 46 in which the pitch of the crochet needles 47 is set to 7 mm, and the fibers are well entangled with each other through the second roller 45 in which the roll gap is set to 1.5 mm, and the fibers do not fall off. 1.5 mm, porosity 90%
A (negative electrode) substrate 30 having the form shown in FIG. 4 was obtained.

If the porosity of the electrode substrate is too small, the filling amount of the positive electrode active material mixture and the negative electrode active material mixture decreases,
No increase in battery capacity can be expected. On the contrary, when the porosity is excessive, the strength of the electrode plate is lowered, the electric conductivity is lowered, and the holding power of the active material mixture for positive and negative electrodes is lowered. Therefore, the porosity is preferably 50 to 98%, and among them, 60 to 95%.
Is the best.

[0032]

The present invention has the following effects due to the above configuration. The electrode substrate for a battery according to claim 1 has a porosity of 50 to 9.
It is characterized in that it is 8% and is a mat-like non-woven fabric of metal fibers sewn with threads to prevent fraying. The type of thread differs depending on the active material mixture for the battery, but for battery component materials (active material agents, etc.) such as nylon fiber thread, synthetic fiber thread such as polyester fiber thread or carbon fiber thread, and glass fiber thread. Inert ones are preferred. Since the positive electrode active material mixture and the negative electrode active material mixture permeate well into the mat-like nonwoven fabric, there is no risk of the positive electrode active material and the negative electrode active material mixture falling off. Since the whole is sewn with an inert thread, there is no problem such as a side reaction (generation of a local battery) when assembled in a battery. Therefore, it is possible to easily provide a high-capacity positive electrode substrate and a high-capacity negative electrode substrate that are resistant to bending.

The battery electrode substrate according to claim 2 has a porosity of 5
It is characterized in that it is 0 to 98% and is made by attaching a metal foil to one or both sides of a mat-like non-woven fabric of metal fibers and sewing the whole with thread to prevent fraying. Since the positive electrode active material mixture paste and the negative electrode active material mixture paste permeate well into the composite mat-like non-woven fabric with the metal foil, there is no risk of the positive electrode active material and negative electrode active material mixture falling off. Since the whole is sewn with an inert thread, there is no problem such as a side reaction (generation of a local battery) when assembled in a battery. Therefore, it is possible to easily provide a high-capacity positive electrode substrate and a high-capacity negative electrode substrate that are resistant to bending.

The electrode substrate for a battery according to claim 3 has a porosity of 5
It is characterized in that it is 0 to 98% and the mat-like non-woven fabric of metal fibers is entirely fray-prevented by the needle punching method. Since the positive electrode active material mixture paste and the negative electrode active material mixture paste permeate well into the composite mat-like non-woven fabric with the metal foil, there is no risk of the positive electrode active material and negative electrode active material mixture falling off. Since the whole is connected by a needle loop, there is no problem such as side reaction (generation of local battery) when assembled in a battery.
Therefore, it is possible to easily provide a high-capacity positive electrode substrate and a high-capacity negative electrode substrate that are resistant to bending.

A fourth aspect of the invention is characterized in that the metal fiber is aluminum or copper. Since easily available aluminum or copper is used, the cost of the electrode substrate can be reduced.

According to a fifth aspect of the present invention, a matting non-woven fabric made of metal fibers is rolled down by a first roller to increase its density, a stitching process for sewing down the matted non-woven fabric entirely with a sewing machine, and a second roller. This is a method of manufacturing a battery electrode substrate, which comprises a finishing step of flattening the upper and lower surfaces of the electrode substrate, and a large number of electrode substrates can be produced at low cost.

According to a sixth aspect of the present invention, there is provided a step of rolling down the mat-shaped nonwoven fabric of metal fibers with a first roller to increase the density, and a stitching step of sewing the rolled down mat-shaped nonwoven fabric as a whole with a needle punch machine. This is a method for manufacturing a battery electrode substrate, which comprises a finishing process in which the upper and lower surfaces are flattened by two rollers, and a large number of electrode substrates can be produced inexpensively.

[Brief description of drawings]

FIG. 1 is an enlarged cross-sectional view of a battery electrode substrate according to a first embodiment of the present invention.

FIG. 2 is an enlarged cross-sectional view of a battery electrode substrate according to a second embodiment of the present invention.

FIG. 3 is an enlarged cross-sectional view of a battery electrode substrate according to a third embodiment of the present invention.

FIG. 4 is an enlarged cross-sectional view of a battery electrode substrate according to a fourth embodiment of the present invention.

FIG. 5 is a manufacturing procedure diagram of the first to third embodiments of the present invention.

FIG. 6 is a manufacturing procedure diagram of a fourth embodiment of the present invention.

FIG. 7: Principle of configuration of cylindrical lithium secondary battery

[Explanation of symbols]

1, 10, 20, 30 ... Battery electrode substrate, 2, 11, 2
1,31 ... Mat fiber non-woven fabric, 3,13,23
... sewing thread, 12, 22 ... metal foil, 32 ... needle loop, 41 ... first roller, 42 ... sewing machine, 43 ... sewing needle,
44 ... Bobbin, 45 ... 2nd roll, 46 ... Needle punch machine, 47 ... Crochet.

Claims (6)

[Claims] 1. A battery electrode substrate for applying an active material mixture for a battery, wherein the battery electrode substrate has a porosity of 50 to 98% and a mat-shaped nonwoven fabric of metal fibers is sewn with a thread. An electrode substrate for a battery, characterized in that it is provided with anti-raveling. 2. A battery electrode substrate for applying an active material mixture for a battery, wherein the battery electrode substrate has a porosity of 50 to 98% and one or more surfaces of a mat-shaped nonwoven fabric of metal fibers. An electrode substrate for a battery, characterized in that metal foil is attached to both sides and the whole is sewn with thread to prevent fraying. 3. A battery electrode substrate for applying an active material mixture for a battery, wherein the battery electrode substrate has a porosity of 50 to 98% and a needle punch method is applied to a mat-shaped nonwoven fabric of metal fibers. An electrode substrate for a battery, characterized in that it has been subjected to fray prevention as a whole. 4. The electrode substrate for a battery according to claim 1, wherein the metal fiber is aluminum or copper. 5. A reduction process for reducing the density of a metal fiber mat-shaped nonwoven fabric by a first roller to increase the density, a stitching process for sewing down the pressed mat-shaped nonwoven fabric with a sewing machine, and a second roller for the upper and lower surfaces. A method of manufacturing a battery electrode substrate, which comprises a finishing step of flattening the surface. 6. A reduction process for reducing the density of a metal fiber mat-shaped non-woven fabric by a first roller to increase the density, a stitching process for sewing the reduced mat-shaped non-woven fabric as a whole with a needle punch machine, and a second roller. A method of manufacturing a battery electrode substrate, comprising a finishing step of flattening the upper and lower surfaces.