JP2022077128A - Battery cell and manufacturing method - Google Patents

Abstract

To provide a battery cell in which bending of electrode tabs is suppressed and a manufacturing method thereof.SOLUTION: A manufacturing method of a battery cell includes the steps of forming an active material layer and an uncoated portion on a long core material by applying a slurry containing a conductive material to a part of the core material, and applying compressive force to the active material layer with a compression roll while applying tension to the core material. In the step of applying compressive force to the active material layer, the compression roll and the uncoated portion are separated from each other.SELECTED DRAWING: Figure 5

Description

This technique relates to a battery cell and a method for manufacturing the same.

Japanese Unexamined Patent Publication No. 2015-176773 (Patent Document 1) shows that a plurality of wrinkles (unevenness) extending in a straight line are formed on an uncoated portion of an electrode plate.

JP-A-2015-176737A

In an electrode plate having a main body and an electrode tab, it is required to improve the strength of the electrode tab against bending. The battery described in Patent Document 1 has a winding type electrode body structure, and its premise configuration is completely different from that of an electrode body having an electrode tab. The conventional structure is not always sufficient from the viewpoint of suppressing the bending of the electrode tab.

An object of the present art is to provide a battery cell in which bending of an electrode tab is suppressed and a method for manufacturing the same.

The method for manufacturing a battery cell according to this technique is a step of forming an active material layer and an uncoated portion on the core material by applying a slurry containing a conductive material to a part of the long core material. It is provided with a step of applying a compressive force to the active material layer by a compression roll while applying tension to the core material. In the process of applying a compressive force to the active material layer, the compression roll and the uncoated portion are separated from each other.

In one aspect, the battery cell according to the present technology includes an active material layer provided on a core material and an uncoated portion, and includes a main body portion and an electrode plate having an electrode tab protruding from the main body portion. Unevenness is formed on the uncoated part located at the base of the electrode tab.

In another aspect, the battery cell according to the present technique is located in a core material having a first region and a second region, an active material layer provided on the first region of the core material, and a second region of the core material. An electrode plate including an uncoated part is provided. The electrode plate has a main body portion including a first region of the core material and an electrode tab including a second region of the core material. The tensile breaking strength of the electrode plate differs between the first region and the second region.

According to the present technique, it is possible to provide a battery cell in which bending of an electrode tab is suppressed and a method for manufacturing the same.

It is a perspective view of a square secondary battery. FIG. 2 is a sectional view taken along line II-II in FIG. It is a figure which shows the 1st process of the manufacturing method of a battery cell. It is a figure which shows the 2nd process of the manufacturing method of a battery cell. It is a figure which shows the 3rd process of the manufacturing method of a battery cell. It is a figure which shows the 4th process of the manufacturing method of a battery cell. It is an enlarged view which shows the structure around the electrode tab. It is a figure which shows the cutout part for a sample. It is a figure which shows the formation method of the annular sample. It is a figure (the 1) which shows the process of applying a compressive force to an annular sample. It is a figure (the 2) which shows the process of applying a compressive force to an annular sample. It is a figure which shows the measurement result of the reaction force when the compressive force is applied to the annular sample. It is a figure which shows the 1st region and the 2nd region of a core material.

Hereinafter, embodiments of the present technology will be described. In some cases, the same or corresponding parts are designated by the same reference numeral and the description thereof may not be repeated.

In the embodiments described below, when the number, quantity, etc. are referred to, the scope of the present technique is not necessarily limited to the number, quantity, etc., unless otherwise specified. Further, in the following embodiments, each component is not necessarily essential for the present technique unless otherwise specified.

In addition, in this specification, the description of "comprise", "include", and "have" is in an open-ended format. That is, it includes certain configurations, but does not exclude inclusion of other calibrations other than those configurations.

FIG. 1 is a perspective view of the square secondary battery 1. FIG. 2 is a sectional view taken along line II-II in FIG.

As shown in FIGS. 1 and 2, the square secondary battery 1 includes a battery case 100, an electrode body 200, an insulating sheet 300, a positive electrode terminal 400, a negative electrode terminal 500, a positive electrode current collector member 600, and a negative electrode. The current collector member 700 and the cover member 800 are included.

The battery case 100 includes a bottomed square cylindrical outer body 110 having an opening and a sealing plate 120 for sealing the opening of the square outer body 110. The square exterior body 110 and the sealing plate 120 are preferably made of metal, and preferably made of aluminum or an aluminum alloy.

The sealing plate 120 is provided with an electrolytic solution injection hole 121. After the electrolytic solution is injected into the battery case 100 from the electrolytic solution injection hole 121, the electrolytic solution injection hole 121 is sealed by the sealing member 122. As the sealing member 122, for example, a blind rivet and other metal members can be used.

The sealing plate 120 is provided with a gas discharge valve 123. The gas discharge valve 123 breaks when the pressure in the battery case 100 exceeds a predetermined value. As a result, the gas inside the battery case 100 is discharged to the outside of the battery case 100.

The electrode body 200 is housed in the battery case 100 together with the electrolytic solution. The electrode body 200 is formed by alternately laminating a single-leaf positive electrode plate and a single-leaf negative electrode plate via a separator. A resin insulating sheet 300 is arranged between the electrode body 200 and the square exterior body 110.

At the end of the electrode body 200 on the sealing plate 120 side, a positive electrode laminated tab 210 and a negative electrode laminated tab 220 that protrude from the positive electrode plate or the negative electrode plate and are laminated thereof are provided.

The positive electrode laminated tab 210 and the positive electrode terminal 400 are electrically connected to each other via a positive electrode current collector member 600. The positive electrode current collector 600 includes a first positive electrode current collector 610 and a second positive electrode current collector 620. The positive electrode current collector member 600 may be composed of one component. The positive electrode current collector member 600 is preferably made of metal, and more preferably made of aluminum or an aluminum alloy.

The negative electrode laminated tab 220 and the negative electrode terminal 500 are electrically connected via the negative electrode current collector 700. The negative electrode current collector 700 includes a first negative electrode current collector 710 and a second negative electrode current collector 720. The negative electrode current collector 700 may be composed of one component. The negative electrode current collector 700 is preferably made of metal, more preferably copper or a copper alloy.

The positive electrode terminal 400 is fixed to the sealing plate 120 via a resin outer insulating member 410. The negative electrode terminal 500 is fixed to the sealing plate 120 via a resin outer insulating member 510.

The positive electrode terminal 400 is preferably made of metal, more preferably aluminum or an aluminum alloy. The negative electrode terminal 500 is preferably made of metal, more preferably copper or a copper alloy. The negative electrode terminal 500 may have a region made of copper or a copper alloy arranged on the inner side of the battery case 100 and a region made of aluminum or an aluminum alloy arranged on the outer side of the battery case 100.

The cover member 800 is located between the first positive electrode current collector 610 and the electrode body 200. The cover member 800 may be provided on the negative electrode current collector side. Further, the cover member 800 is not an essential member and can be omitted as appropriate.

3 to 6 are views showing each manufacturing process of the electrode body 200 of the square secondary battery 1. Although the positive electrode plate will be described below, the same configuration can be adopted for the negative electrode plate.

As shown in FIG. 3, a long core material 10 is prepared. The core material 10 is made of, for example, aluminum foil.

Next, as shown in FIG. 4, the slurry is applied onto the core material 10 to form the positive electrode active material mixture layer 11 and the protective layer 12 (they may be collectively referred to as an “active material layer”). Will be done.

The positive electrode active material mixture layer 11 is formed on both surfaces of the core material 10. The positive electrode active material mixture layer 11 contains a positive electrode active material (for example, lithium nickel cobalt manganese composite oxide, etc.), a binder (polyvinylidene fluoride (PVdF), etc.), and a conductive material (for example, carbon material, etc.).

The protective layer 12 is formed on both sides of the core material 10. The protective layer 12 contains alumina particles, a binder, and a conductive material. The protective layer 12 does not have to be formed.

The positive electrode active material mixture layer 11 and the protective layer 12 are formed leaving a part of the surface of the core material 10. The region where the positive electrode active material mixture layer 11 and the protective layer 12 are not formed is the uncoated portion 13.

Further, as shown in FIG. 5, the active material layer (positive electrode active material mixture layer 11 and protective layer 12) is subjected to the compression roll 900 while applying tension (in the left-right direction and the vertical direction in the figure) to the core material 10. Compressive force is applied. At this time, the first portion 910 of the compression roll 900 is in contact with the positive electrode active material mixture layer 11 and the protective layer 12, and the second portion 920 of the compression roll 900 is separated from the uncoated portion 13. The diameter of the second portion 920 of the compression roll 900 is smaller than the diameter of the first portion 910.

As a result, in the region (first region) where the positive electrode active material mixture layer 11 and the protective layer 12 are formed, a compressive force is applied to the core material 10 and a force to stretch the core material 10 acts. On the other hand, in the region (second region) where the uncoated portion 13 is located, no compressive force is applied to the core material 10, and no force for stretching the core material 10 acts. More specifically, the first region (mixed material portion) is stretched in the longitudinal direction by about 0.6% or more and 1.0% or less as compared with the second region (foil portion). As a result, a pattern 14 (unevenness) is formed at the boundary portion between the protective layer 12 and the uncoated portion 13, and more specifically, at the portion of the uncoated portion 13 adjacent to the protective layer 12.

The pattern 14 extends in an oblique direction with respect to a long longitudinal direction (left-right direction in FIG. 5). The extending direction of the pattern 14 is preferably inclined by about 5 ° or more and 30 ° or less with respect to the long longitudinal direction (left-right direction in FIG. 5). The depth of the unevenness of the pattern 14 is preferably about 0.025 mm or more and 0.055 mm or less. The width of the pattern 14 (in the vertical direction in FIG. 5) is preferably about 3 mm or more and 10 mm or less.

Then, as shown in FIG. 6, the core material 10 of the protective layer 12 portion and the uncoated portion 13 portion is cut, and the positive electrode tab 210A (electrode tab) protruding from the main body portion 200A and the main body portion 200A is cut out. Then, at a predetermined position of the main body portion 200A, a single-wafer-shaped positive electrode plate (electrode plate) is created by cutting vertically in the long longitudinal direction (vertical direction in FIG. 5). Then, the single-wafer-shaped positive electrode plate is alternately laminated with the separately formed single-wafer-shaped negative electrode plate via a separator to produce the electrode body 200.

FIG. 7 is an enlarged view showing the structure around the positive electrode tab 210A. As shown in FIG. 7, the pattern 14 is formed on the uncoated portion 13 located at the root portion of the positive electrode tab 210A.

FIG. 8 is a diagram showing a cutout portion 10A for a sample. As shown in FIG. 8, the cutout portion 10A is cut out from the core material 10 before cutting out the positive electrode plate having the main body portion 200A and the positive electrode tab 210A. The cutout portion 10A is cut out from the unpainted portion 13 including the pattern 14.

FIG. 9 is a diagram showing a method of forming a sample for measuring the strength of the positive electrode tab 210A against bending. By forming the cutout portion 10A shown in FIG. 9A into an annular shape, the annular sample 10B shown in FIG. 9B is formed.

10 and 11 are diagrams showing a step of applying a compressive force to the annular sample 10B. As shown in FIG. 10, the annular sample 10B is placed on the table 21 of the jig 20, and the annular sample 10B is fixed to the table 21 by the tape 10C. The jig 20 is set in the autograph. A compressive force is applied to the annular sample 10B via the pressing member 22 by the autograph. As shown in FIG. 11, the annular sample 10B is compressed until its height reaches H (mm).

FIG. 12 is a diagram showing a measurement result of a reaction force when a compressive force is applied to the annular sample 10B. As shown in FIG. 12, for each case of H = 0.5 mm, 1.0 mm, and 1.5 mm, the depth of the unevenness of the pattern 14 is changed between 0 mm and 0.070 mm (“0 mm” is the pattern 14). (Meaning none), when the pressing member 22 is moved by the autograph and the annular sample 10B is compressed and deformed until H reaches a predetermined value (0.5 mm, 1.0 mm, 1.5 mm). As a result of comparing the measured reaction forces (N), it was shown that when the unevenness of the pattern 14 was 0.025 mm and 0.055 mm, a relatively high reaction force was exhibited. This indicates that the reaction force against bending of the positive electrode tab 210A is high in the range where the unevenness depth of the pattern 14 is about 0.025 mm or more and 0.055 mm or less.

FIG. 13 is a diagram showing a first region 10α and a second region 10β of the core material 10. The first region 10α is located in the portion where the positive electrode active material mixture layer 11 is coated. The second region 10β is located in the uncoated portion 13. The first region 10α and the second region 10β have the same shape as each other.

Both ends of the sample cut out in the first region 10α and the second region 10β shown in FIG. 13 were pulled using an autograph, and the strength and elongation when the sample broke were measured. As a result, the tensile breaking strengths of the samples differ from each other in the first region 10α and the second region 10β. More specifically, although the first region 10α and the second region 10β of the core material 10 have the same shape, the tensile breaking load of the second region 10β is larger than that of the first region 10α. .. This is because in the first region 10α, the core material 10 is already rolled in the longitudinal direction by the compression roll 900 and the thickness is relatively small (thin), whereas in the second region 10β, the compression roll is used. It is considered that this is because the compressive force of 900 does not act on the core material 10 and the thickness of the core material 10 is relatively larger (thicker) than the first region 10α.

As described above, according to the square secondary battery 1 according to the present embodiment, the pattern 14 formed on the uncoated portion 13 located at the root portion of the positive electrode tab 210A suppresses the bending of the positive electrode tab 210A. Is possible. Similar effects can be obtained with the negative electrode tab.

Although the embodiments of the present technology have been described above, it should be considered that the embodiments disclosed this time are exemplary in all respects and are not restrictive. The scope of the present invention is indicated by the scope of claims and is intended to include all modifications within the meaning and scope equivalent to the scope of claims.

1 Square secondary battery, 10 core material, 10A cutout part, 10B annular sample, 10C tape, 10α 1st region, 10β 2nd region, 11 positive electrode active material mixture layer, 12 protective layer, 13 uncoated part, 14 Pattern, 20 jigs, 21 tables, 22 pressing members, 100 battery cases, 110 square exterior bodies, 120 sealing plates, 121 electrolyte injection holes, 122 sealing members, 123 gas discharge valves, 200 electrode bodies, 200A main body , 210 Positive Electrode Laminated Tab, 220 Negative Electrode Laminated Tab, 210A Positive Electrode Tab, 300 Insulation Sheet, 400 Positive Electrode Terminal, 410 External Insulation Member, 500 Negative Electrode Terminal, 510 External Insulation Member, 600 Positive Electrode Collector, 610 First Positive Electrode Collection Electric body, 620 second positive electrode collector, 700 negative electrode current collector, 710 first negative electrode collector, 720 second negative electrode collector, 800 cover member, 900 compression roll, 910 first part (compression part), 920 Second part (separated part).

Claims (10)

A step of forming an active material layer and an uncoated portion on the core material by applying a slurry containing a conductive material to a part of the long core material.
A step of applying a compressive force to the active material layer by a compression roll while applying tension to the core material is provided.
A method for manufacturing a battery cell in which the compression roll and the uncoated portion are separated from each other in the step of applying the compressive force to the active material layer. Claim 1 in the step of applying the compressive force to the active material layer, unevenness extending in an oblique direction with respect to the long longitudinal direction is formed in a portion of the uncoated portion adjacent to the active material layer. The method for manufacturing a battery cell described in 1. The method for manufacturing a battery cell according to claim 2, wherein the depth of the unevenness is 0.025 mm or more and 0.055 mm or less. After the step of applying the compressive force to the active material layer, the claim further comprises a step of cutting the long core material to cut out a main body portion and an electrode plate having an electrode tab protruding from the main body portion. The method for manufacturing a battery cell according to any one of claims 1 to 3. The method for manufacturing a battery cell according to claim 4, wherein the electrode plate is a positive electrode plate. It includes an active material layer provided on a core material and an uncoated portion, and is provided with an electrode plate having a main body portion and an electrode tab protruding from the main body portion.
A battery cell in which irregularities are formed on the uncoated portion located at the base of the electrode tab. The battery cell according to claim 6, wherein the unevenness extends in an oblique direction with respect to a boundary between the main body and the electrode tab. The battery cell according to claim 6 or 7, wherein the unevenness has a depth of 0.025 mm or more and 0.055 mm or less. An electrode plate including a core material having a first region and a second region, an active material layer provided on the first region of the core material, and an uncoated portion located in the second region of the core material is provided.
The electrode plate has a main body portion including the first region of the core material and an electrode tab including the second region of the core material.
A battery cell in which the tensile breaking strengths of the electrode plates differ from each other in the first region and the second region. The battery cell according to any one of claims 6 to 9, wherein the electrode plate is a positive electrode plate.

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