JP2022086352A - Battery and manufacturing method thereof - Google Patents

Abstract

To provide a battery in which the operation of a current cutoff mechanism is stable and a manufacturing method of the battery.SOLUTION: On the first surface of a deformation plate of a current cutoff mechanism, a substantially annular first groove is formed in a first region which is on the outer peripheral side of a thick portion and in which a distance from the center of the deformation plate is smaller than half of a distance from the center to the outer peripheral edge of the deformation plate, and on the second surface of the deformation plate, a substantially annular second groove is formed in a second region in which the distance from the center of the deformation plate is larger than half the distance from the center to the outer peripheral edge of the deformation plate. The deformation plate can be joined to a current collector in a state in which stress in the direction of closing the openings of the first groove and the second groove is generated in the deformation plate.SELECTED DRAWING: Figure 17

Description

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

Conventionally, a battery having a current cutoff mechanism capable of operating when the pressure in the battery case rises excessively to cut off the conductive path has been known. Such a structure is shown in, for example, JP-A-2010-21304 (Patent Document 1) and JP-A-2019-87478 (Patent Document 2).

Japanese Unexamined Patent Publication No. 2010-21024 Japanese Unexamined Patent Publication No. 2019-87478

In the current cutoff mechanism, when the pressure inside the battery case rises, the central part of the deformed plate is deformed so as to move toward the sealing plate, so that the welded joint between the current collector and the deformed plate breaks. .. As a result, the conductive path between the electrode terminal and the electrode body is cut.

The deformed plate and the current collector are welded and joined in a state where the deformed plate is bent in a direction in which the central portion of the deformed plate is separated from the sealing plate. At this time, if the bending deformation amount of the deformed plate is not stable, the breaking load of the welded joint between the current collector and the deformed plate is not stable, and as a result, the operation of the current cutoff mechanism is not stable. The conventional current cutoff mechanism is not always sufficient from this point of view.

An object of the present art is to provide a battery in which the operation of the current cutoff mechanism is stable and a method for manufacturing the same.

The battery according to the present technology is connected to the electrode body, the exterior body accommodating the electrode body, the battery case including the sealing plate for sealing the exterior body, the terminal portion attached to the sealing plate, and the terminal portion, and is connected to the electrode body side. A conductive member having an opening, a deformable plate for sealing the opening of the conductive member, and a current collector joined to the deformable plate are provided. The electrode body is electrically connected to the terminal portion via a current collector, a deforming plate, and a conductive member. When the pressure inside the battery case exceeds a predetermined value, the deformable plate is deformed, and the electrical connection between the electrode body and the terminal portion is cut off. The deformable plate has a first surface on the sealing plate side and a second surface on the electrode body side. The deformed plate may further have a thick portion in a region including its center, which is relatively thicker than its surroundings.

In one aspect, a region on the first surface of the deformed plate that is on the outer peripheral side of the thick portion and the distance from the center of the deformed plate is less than half the distance from the center to the outer peripheral edge of the deformed plate. A substantially annular groove is formed in. Here, the deformed plate is joined to the current collector in a state where stress in the direction of closing the opening of the groove is generated in the deformed plate.

In another aspect, a substantially annular groove is formed on the second surface of the deformed plate in a region where the distance from the center of the deformed plate is greater than half the distance from the center to the outer peripheral edge of the deformed plate. Here, the deformed plate is joined to the current collector in a state where stress in the direction of closing the opening of the groove is generated in the deformed plate.

In yet another aspect, on the first surface of the deformed plate, it is on the outer peripheral side of the thick portion and the distance from the center of the deformed plate is smaller than half of the distance from the center to the outer peripheral edge of the deformed plate. A substantially annular first groove is formed in the first region, and the distance from the center of the deformed plate is larger than half of the distance from the center to the outer peripheral edge of the deformed plate on the second surface of the deformed plate. A substantially annular second groove is formed.

Here, the deformed plate can be joined to the current collector in a state where stress in the direction of closing the openings of the first groove and the second groove is generated in the deformed plate. Further, the first groove and the second groove may have a cross-sectional shape in which the width of the opening is wider than the width of the bottom in a state where the deformed plate is separated from the current collector.

The method for manufacturing a battery according to the present technology includes a step of connecting an electrode body and a current collector, a step of attaching a terminal portion and a conductive member to a sealing plate of a battery case, and a first surface and a second surface. A step of preparing a deformed plate in which a thick portion having a thickness relatively larger than that of the surroundings is formed in a region including the center, a step of forming a substantially annular groove in the deformed plate, and a step of forming a substantially annular groove in the deformed plate. 1 With the surface facing the sealing plate side and the second surface of the deforming plate facing the electrode body side, the process of sealing the opening of the conductive member attached to the sealing plate with the deforming plate and closing the groove opening. A process of electrically connecting the electrode body and the terminal portion via the current collector, the deformed plate, and the conductive member by joining the deformed plate and the current collector in a state where the deformed plate is deformed in the direction. A step of accommodating the electrode body in the exterior body and sealing the exterior body with a sealing plate is provided.

In one aspect, the step of forming a substantially annular groove in the deformed plate is on the outer peripheral side of the thick portion on the first surface of the deformed plate, and the distance from the center of the deformed plate is deformed from the center. It involves forming a substantially annular groove in a region less than half the distance to the outer perimeter of the plate.

In another aspect, the step of forming a substantially annular groove in the deformed plate is such that the distance from the center of the deformed plate is greater than half the distance from the center to the outer peripheral edge of the deformed plate on the second surface of the deformed plate. Includes forming a substantially annular groove in the region.

In yet another aspect, the step of forming a substantially annular groove in the deformed plate is on the outer peripheral side of the thick portion on the first surface of the deformed plate, and the distance from the center of the deformed plate is from the center. A substantially annular first groove is formed in the first region, which is smaller than half the distance to the outer peripheral edge of the deformed plate, and the distance from the center of the deformed plate on the second surface of the deformed plate is from the center to the deformed plate. It involves forming a substantially annular second groove in a second region that is greater than half the distance to the outer perimeter of the.

In yet another aspect, the step of forming a substantially annular groove in the deformed plate is on the outer peripheral side of the thick portion on the first surface of the deformed plate, and the distance from the center of the deformed plate is from the center. In the first region, which is less than half the distance to the outer peripheral edge of the deformed plate, a substantially annular first groove having a cross-sectional shape having a wider opening width than the width of the bottom is formed, and the second surface of the deformed plate is formed. Above, a substantially annular second having a cross-sectional shape in which the width of the opening is wider than the width of the bottom in the second region where the distance from the center of the deformed plate is greater than half the distance from the center to the outer peripheral edge of the deformed plate. Includes forming a groove.

According to the present technique, it is possible to provide a battery in which the operation of the current cutoff mechanism is stable 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 top view of the positive electrode plate which constitutes an electrode body. It is a top view of the negative electrode plate which constitutes an electrode body. It is a top view which shows the electrode body which consists of a positive electrode plate and a negative electrode plate. It is a figure which shows the connection structure of an electrode body, a positive electrode current collector member, and a negative electrode current collector member. It is a figure which shows the attachment structure of the positive electrode current collector member and the negative electrode current collector member to a sealing plate. FIG. 7 is a sectional view taken along line VIII-VIII in FIG. FIG. 7 is a cross-sectional view taken along the line IX-IX in FIG. It is a figure which shows the state which the sealing plate and the electrode body are connected. It is an enlarged view around the positive electrode current collector member in the state where the sealing plate and the electrode body are connected. It is sectional drawing of the deforming plate. It is a top view of the deforming plate. It is a bottom view of a deforming plate. It is an enlarged view which shows the periphery of the α part in FIG. It is an enlarged view which shows the periphery of the β part in FIG. 12 is a cross-sectional view showing a state in which the deformed plates shown in FIGS. 12 to 16 are deformed and joined to a current collector. It is a figure which shows the deformation example of the shape of the groove formed in the deforming plate.

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 art unless otherwise specified.

In addition, in this specification, the description of "comprise", "include", and "have" is in an open-ended format. That is, when a certain configuration is included, other configurations other than the configuration may or may not be included. In addition, the present technique is not necessarily limited to those that exhibit all the actions and effects referred to in the present embodiment.

As used herein, the "battery" is not limited to a lithium ion battery and may include other batteries such as nickel metal hydride batteries. In the present specification, "electrode" may collectively refer to a positive electrode and a negative electrode. Further, the "electrode plate" may collectively refer to a positive electrode plate and a negative electrode plate.

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 600, and a negative electrode. It includes a current collecting member 700, a current cutoff mechanism 800, and a cover member 900.

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 laminating a positive electrode plate and a negative electrode plate via a separator. A resin insulating sheet 300 is arranged between the electrode body 200 and the square exterior body 110.

A positive electrode tab 210A and a negative electrode tab 210B are provided at the end of the electrode body 200 on the sealing plate 120 side.

The positive electrode tab 210A 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 tab 210B and the negative electrode terminal 500 are electrically connected via the negative electrode current collector member 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 current cutoff mechanism 800 is provided in the conductive path between the positive electrode tab 210A (positive electrode plate) and the positive electrode terminal 400. The current cutoff mechanism 800 operates when the pressure in the battery case 100 becomes a predetermined value or more, and can cut off the conductive path. The working pressure of the gas discharge valve 123 is set to a value larger than the working pressure of the current cutoff mechanism 800. The current cutoff mechanism 800 can also be provided in the conductive path between the negative electrode tab 210B and the negative electrode terminal 500.

FIG. 3 is a plan view of the positive electrode plate 200A constituting the electrode body 200. The positive electrode plate 200A has a positive electrode active material (for example, lithium nickel cobalt manganese composite oxide, etc.), a binder (polyfluoride vinylidene (PVdF), etc.), and a conductive material (for example, on both sides of a positive electrode core made of a rectangular aluminum foil. It has a main body 220A on which a positive electrode active material mixture layer containing (for example, a carbon material) is formed. A positive electrode core protrudes from the end edge of the main body, and the protruding positive electrode core constitutes the positive electrode tab 210A. A positive electrode protective layer 230A containing alumina particles, a binder, and a conductive material is provided in a portion of the positive electrode tab 210A adjacent to 220A of the main body. The positive electrode protective layer 230A has an electric resistance larger than the electric resistance of the positive electrode active material mixture layer. The positive electrode active material mixture layer does not need to contain a conductive material. The positive electrode protective layer 230A does not necessarily have to be provided.

FIG. 4 is a plan view of the negative electrode plate 200B constituting the electrode body 200. The negative electrode plate 200B has a main body portion 220B in which negative electrode active material layers are formed on both sides of a negative electrode core made of rectangular copper foil. The negative electrode core body protrudes from the end side of the main body portion 220B, and the protruding negative electrode core body constitutes the negative electrode tab 210B.

FIG. 5 is a plan view showing an electrode body 200 composed of a positive electrode plate 200A and a negative electrode plate 200B. As shown in FIG. 5, the electrode body 200 is manufactured so that the positive electrode tabs 210A of each positive electrode plate 200A are laminated at one end and the negative electrode tabs 210B of each negative electrode plate 200B are laminated. The positive electrode plate 200A and the negative electrode plate 200B are stacked, for example, about 50 sheets each. The positive electrode plate 200A and the negative electrode plate 200B are alternately laminated via a rectangular separator made of polyolefin. A long separator may be folded in a zigzag manner.

FIG. 6 is a diagram showing a connection structure between the electrode body 200, the positive electrode current collector member 600, and the negative electrode current collector member 700. As shown in FIG. 6, the electrode body 200 is composed of a first electrode body element 201 (first laminated group) and a second electrode body element 202 (second laminated group). Separators are also arranged on the outer surfaces of the first electrode body element 201 and the second electrode body element 202, respectively. The first electrode body element 201 and the second electrode body element 202 can be fixed in a laminated state with, for example, tape or the like. Alternatively, an adhesive layer may be provided on each of the positive electrode plate 200A, the negative electrode plate 200B, and the separator so that the separator and the positive electrode plate 200A are adhered to each other, and the separator and the negative electrode plate 200B are adhered to each other.

A plurality of positive electrode tabs 210A of the first electrode body element 201 constitute the first positive electrode tab group 211A. A plurality of negative electrode tabs 210B of the first electrode body element 201 constitute the first negative electrode tab group 211B. A plurality of positive electrode tabs 210A of the second electrode body element 202 constitute the second positive electrode tab group 212A. A plurality of negative electrode tabs 210B of the second electrode body element 202 constitute the second negative electrode tab group 212B.

A second positive electrode current collector 620 and a second negative electrode current collector 720 are arranged between the first electrode body element 201 and the second electrode body element 202. The second positive electrode current collector 620 has a first opening 620A and a second opening 620B. The first positive electrode tab group 211A and the second positive electrode tab group 212A are welded and connected on the second positive electrode current collector 620 to form a welded connection portion 213. The first negative electrode tab group 211B and the second negative electrode tab group 212B are welded and connected on the second negative electrode current collector 720 to form a welded connection portion 213. The weld connection portion 213 can be formed by, for example, ultrasonic welding, resistance welding, laser welding, or the like.

FIG. 7 is a diagram showing an attachment structure of the positive electrode current collector member 600 and the negative electrode current collector member 700 to the sealing plate 120. FIG. 8 shows a cross section of VIII-VIII in FIG. FIG. 9 shows an IX-IX cross section in FIG.

First, the attachment of the positive electrode current collector member 600 to the sealing plate 120 will be described with reference to FIGS. 7 and 8.

An external insulating member 410 made of resin is arranged on the outer surface side of the sealing plate 120. A resin insulating member 420 and a conductive member 430 are arranged on the inner surface side of the sealing plate 120. After that, the positive electrode terminal 400 is inserted into the through hole of the external insulating member 410, the positive electrode terminal mounting hole of the sealing plate 120, the through hole of the insulating member 420, and the through hole of the conductive member 430. Then, the tip of the positive electrode terminal 400 is caulked and connected onto the conductive member 430. As a result, the positive electrode terminal 400, the external insulating member 410, the sealing plate 120, the insulating member 420, and the conductive member 430 are fixed. The portions of the positive electrode terminal 400 and the conductive member 430 that are caulked and connected are preferably welded by laser welding or the like.

The conductive member 430 has a conductive member base portion 431 and a tubular portion 432 extending from the edge portion of the conductive member base portion 431 toward the electrode body 200 (lower side in the figure). An opening 433 is provided at the end of the tubular portion 432 on the electrode body 200 side. The positive electrode terminal 400 and the conductive member 430 may be provided as an integral member.

The deformable plate 440 is arranged so as to close the opening 433 of the conductive member 430. The peripheral edge of the deformable plate 440 is welded to the conductive member 430 by laser welding or the like. As a result, the opening 433 of the conductive member 430 is sealed by the deformable plate 440. The conductive member 430 and the deformed plate 440 are preferably made of metal, and more preferably aluminum or an aluminum alloy.

A protrusion provided on the resin insulating member 630 (positive electrode current collector holder) is inserted into a through hole provided in the first positive electrode current collector 610, and the tip of the protrusion is enlarged by thermal caulking or the like. As a result, the connecting portion 631 is formed, and the first positive electrode current collector 610 and the insulating member 630 can be connected to each other. Further, the displacement prevention portion 632 can be formed by inserting the protrusion provided in the insulating member 630 into the through hole provided in the first positive electrode current collector 610.

The insulating member 630 connected to the first positive electrode current collector 610 and the insulating member 420 on the positive electrode terminal 400 side are connected by fitting. It is also possible to provide a claw portion on the insulating member 630 and hook and connect the claw portion to the insulating member 420.

After that, in the opening provided in the insulating member 630, the first positive electrode current collector 610 on the positive electrode current collecting member 600 side and the central portion of the deformed plate 440 on the positive electrode terminal 400 side are connected by laser welding or the like. .. It is preferable that the first positive electrode current collector 610 is provided with a connection hole, and the edge portion of the connection hole is welded and connected to the deformed plate 440.

As shown in FIG. 8, the insulating member 630 has a cylindrical portion 630A protruding toward the electrode body 200. The tubular portion 630A defines a hole portion 630B that penetrates the second opening 620B of the second positive electrode current collector 620 and communicates with the electrolytic solution injection hole 121.

When attaching the positive electrode current collector 600 to the sealing plate 120, first, the first positive electrode current collector 610 is connected to the insulating member 630 on the sealing plate 120. Subsequently, the second positive electrode current collector 620 connected to the electrode body 200 is attached to the first positive electrode current collector 610. At this time, the second positive electrode current collector 620 is arranged on the insulating member 630 so that a part of the second positive electrode current collector 620 overlaps with the first positive electrode current collector 610. Subsequently, the periphery of the first opening 620A provided in the second positive electrode current collector 620 is welded and connected to the first positive electrode current collector 610 by laser welding or the like.

Next, the attachment of the negative electrode current collector 700 to the sealing plate 120 will be described with reference to FIGS. 7 and 9.

A resin-made external insulating member 510 is arranged on the outer surface side of the sealing plate 120. A first negative electrode current collector 710 and a resin insulating member 730 (negative electrode current collector holder) are arranged on the inner surface side of the sealing plate 120. Next, the negative electrode terminal 500 is inserted into a through hole of the external insulating member 510, a negative electrode terminal mounting hole of the sealing plate 120, a through hole of the first negative electrode current collector 710, and a through hole of the insulating member 730. Then, the tip of the negative electrode terminal 500 is caulked and connected onto the first negative electrode current collector 710. As a result, the negative electrode terminal 500, the external insulating member 510, the sealing plate 120, the first negative electrode current collector 710, and the insulating member 730 are fixed. The portions of the negative electrode terminal 500 and the first negative electrode current collector 710 that are caulked and connected are preferably welded and connected by laser welding or the like.

Further, the second negative electrode current collector 720 is arranged on the insulating member 730 so that a part of the second negative electrode current collector 720 overlaps with the first negative electrode current collector 710. In the first opening 720A provided in the second negative electrode current collector 720, the second negative electrode current collector 720 is welded and connected to the first negative electrode current collector 710 by laser welding or the like.

When attaching the negative electrode current collector 700 to the sealing plate 120, first, the first negative electrode current collector 710 is connected to the insulating member 730 on the sealing plate 120. Subsequently, the second negative electrode current collector 720 connected to the electrode body 200 is attached to the first negative electrode current collector 710. At this time, the second negative electrode current collector 720 is arranged on the insulating member 730 so that a part of the second negative electrode current collector 720 overlaps with the first negative electrode current collector 710. Subsequently, the periphery of the first opening 720A provided in the second negative electrode current collector 720 is welded and connected to the first negative electrode current collector 710 by laser welding or the like.

The operation of the current cutoff mechanism 800 shown in FIG. 8 will be described. As the pressure inside the battery case 100 increases, the central portion of the deformable plate 440 is deformed so as to move toward the sealing plate 120. Then, when the pressure in the battery case 100 becomes a predetermined value or more, the welded joint between the first positive electrode current collector 610 and the deformed plate 440 breaks due to the deformation of the deformed plate 440. As a result, the conductive path from the positive electrode plate 200A to the positive electrode terminal 400 is cut.

When the square secondary battery 1 is in an overcharged state and the pressure inside the battery case 100 rises, the current cutoff mechanism 800 is activated and the conductive path from the positive electrode plate 200A to the positive electrode terminal 400 is cut off, thereby further overcharging. The progress of charging is prevented.

A through hole 400A is formed in the positive electrode terminal 400. By sending gas to the inside of the conductive member 430 through the through hole 400A, a leak inspection of the welded connection portion between the conductive member 430 and the deformed plate 440 can be performed. The through hole 400A is sealed by a terminal sealing member made of resin or metal.

FIG. 10 is a diagram showing a state in which the sealing plate 120 and the electrode body 200 are connected. FIG. 11 is an enlarged view of the periphery of the positive electrode current collector 600 in a state where the sealing plate 120 and the electrode body 200 are connected.

As described with reference to FIGS. 7 to 9, the first electrode body element 201 and the second electrode body element 202 are attached to the sealing plate 120 via the positive electrode current collector member 600 and the negative electrode current collector member 700. As a result, as shown in FIG. 10, the first electrode body element 201 and the second electrode body element 202 are connected to the sealing plate 120, and the electrode body 200, the positive electrode terminal 400, and the negative electrode terminal 500 are electrically connected. ..

As shown in FIG. 11, a resin cover member 900 is provided on the first positive electrode current collector 610. The cover member 900 is located between the first positive electrode current collector 610 and the electrode body 200. The cover member 900 may be provided on the negative electrode current collector side. Further, the cover member 900 is not an essential member and can be omitted as appropriate.

From the state shown in FIG. 10, the first electrode body element 201 and the second electrode body element 202 are combined into one. At this time, the first positive electrode tab group 211A and the second positive electrode tab group 212A are curved in different directions from each other. The first negative electrode tab group 211B and the second negative electrode tab group 212B are curved in different directions from each other.

The first electrode body element 201 and the second electrode body element 202 can be combined into one by tape or the like. Alternatively, the first electrode body element 201 and the second electrode body element 202 can be put together by arranging them in a box-shaped or bag-shaped insulating sheet. Further, the first electrode body element 201 and the second electrode body element 202 can be fixed by adhesion.

The first electrode body element 201 and the second electrode body element 202, which are put together, are wrapped in an insulating sheet and inserted into the square exterior body 110. After that, the sealing plate 120 is welded and connected to the square exterior body 110, the opening of the square exterior body 110 is sealed by the sealing plate 120, and the sealed battery case 100 is formed.

After that, the non-aqueous electrolytic solution is injected into the battery case 100 from the electrolytic solution injection hole 121 provided in the sealing plate 120. As the non-aqueous electrolyte solution, for example, a non-aqueous solvent in which ethylene carbonate (EC), ethyl methyl carbonate (EMC), and diethyl carbonate (DEC) are mixed at a volume ratio (25 ° C.) of 30:30:40. In addition, LiPF ₆ dissolved at a concentration of 1.2 mol / L can be used.

After the non-aqueous electrolytic solution is injected, the electrolytic solution injection hole 121 is sealed by the sealing member 122. By carrying out the above steps, the square secondary battery 1 is completed.

As described above, the method for manufacturing the square secondary battery 1 includes a step of connecting the electrode body 200 and the first positive electrode current collector 610, and the positive electrode terminal 400 (terminal portion) and the conductive member 430 of the battery case 100. The process of attaching to the sealing plate 120 and the opening of the conductive member 430 attached to the sealing plate 120 with the upper surface of the deformed plate 440 facing the sealing plate 120 side and the lower surface of the deforming plate 440 facing the electrode body 200 side. The step of sealing the 433 with the deformed plate 440, the step of joining the deformed plate 440 and the first positive electrode current collector 610, the electrode body 200 is housed in the square outer body 110, and the square outer body 110 is the sealing plate 120. It is provided with a process of sealing by.

The square secondary battery 1 manufactured in this manner includes an electrode body 200, a battery case 100 including a square exterior body 110 accommodating the electrode body 200, and a sealing plate 120 for sealing the square exterior body 110, and a sealing plate 120. A positive electrode terminal 400 (terminal portion) attached to the positive electrode terminal 400, a conductive member 430 connected to the positive electrode terminal 400 and having an opening 433 on the electrode body 200 side, and a deformed plate 440 that seals the opening 433 of the conductive member 430. , A first positive electrode current collector 610 to be joined to the deformed plate 440 is provided.

The electrode body 200 is electrically connected to the positive electrode terminal 400 via the first positive electrode current collector 610, the deformed plate 440, and the conductive member 430. When the pressure in the battery case 100 becomes a predetermined value or more, the deformable plate 440 is deformed, and the electrical connection between the electrode body 200 and the positive electrode terminal 400 is cut off.

12 is a cross-sectional view of the deformed plate 440, FIG. 13 is a top view of the deformed plate 440, and FIG. 14 is a bottom view of the deformed plate 440.

The deformable plate 440 has an upper surface (first surface) on the sealing plate 120 side shown in FIG. 13 and a lower surface (second surface) on the electrode body 200 side shown in FIG. The deformed plate 440 has a thick portion 441 and a thin portion 442. The thick portion 441 is provided in the region including the center of the deformed plate 440, and has a relatively large thickness as compared with the periphery. The thin-walled portion 442 is provided around the thick-walled portion 441 and has a relatively small thickness as compared with the thick-walled portion 441.

By providing the thick portion 441 in the central portion of the deformed plate 440, the workability at the time of welding and joining with the first positive electrode current collector 610 is improved, and the conductive path on the inner peripheral side of the deformed plate 440 is increased. be able to. As a result, it is possible to prevent fusing on the deformable plate 440 even when an unintended large current is energized, and to secure airtightness at the time of abnormality.

As shown in FIGS. 12 and 13, on the upper surface of the deformable plate 440, the outer peripheral side is on the outer peripheral side of the thick portion 441, and the distance from the center of the deformable plate 440 is the distance from the center to the outer peripheral edge of the deformable plate 440. An annular groove 443A (first groove) is formed in the A region (first region) smaller than half of the above.

As shown in FIGS. 12 and 14, in the B region (second region) on the lower surface of the deformable plate 440, the distance from the center of the deformable plate 440 is larger than half of the distance from the center to the outer peripheral edge of the deformable plate 440. An annular groove 443B (second groove) is formed.

The groove 443A and the groove 443B do not have to be completely annular, and may be "substantially annular" in which a groove is not partially formed. The "substantially annular" is preferably about 60% or more, more preferably about 80% or more, and more preferably about 90% or more when the complete annular length is 100%. Is even more preferable. However, when the groove 443A and the groove 443B are divided in the circumferential direction, it is preferable that each of the divided grooves has a shape symmetrical with respect to the center of the "annular".

As shown in FIG. 17, the deformed plate 440 is joined to the first positive electrode current collector 610 in a state where stress in the direction of closing the openings of the grooves 443A and 443B is generated in the deformed plate. Further, the groove 443A and the groove 443B have a cross-sectional shape in which the width of the opening is wider than the width of the bottom in a state where the deformed plate 440 is separated from the first positive electrode current collector 610.

FIG. 15 is an enlarged view showing the periphery of the α portion in FIG. 12, and FIG. 16 is an enlarged view showing the periphery of the β portion in FIG. As shown in FIGS. 15 and 16, the grooves 443A and 443B have a cross-sectional shape in which the width of the opening is wider than the width of the bottom. More specifically, the groove 443A and the groove 443B have a substantially V-shaped cross-sectional shape.

The groove 443A and the groove 443B have the total thickness of the deformed plate 440 at the position where the groove 443A and the groove 443B are formed (the deformed plate when the groove is not formed) in a state where the deformed plate 440 is separated from the first positive electrode current collector 610. It is preferable to have a depth of about 1/3 or more and 1/2 or less of the thickness of 440). By setting the groove depth to this extent, it is possible to suppress an excessive decrease in the cross-sectional area of the deformed plate 440, which is a conductive path, while promoting the desired deformation of the deformed plate 440.

When the pressure in the battery case 100 rises, the joint portion between the deformed plate 440 and the first positive electrode current collector 610 is cut off in the current cutoff mechanism 800. At this time, the portions of the deformed plate 440 in which the grooves 443A and 443B are formed are not cut.

Further, even when a large current flows through the square secondary battery 1, the portions of the deformed plate 440 in which the grooves 443A and 443B are formed do not melt. At this time, the unintended large current is cut off by melting the other fragile parts.

With the deformed plate 440 separated from the first positive electrode current collector 610, the width of the opening of the groove 443A may be formed to be narrower than the width of the opening of the groove 443B. Further, the depth of the groove 443A may be formed to be smaller than the depth of the groove 443B in a state where the deformed plate 440 is separated from the first positive electrode current collector 610.

In the portion where the groove 443A located on the inner peripheral side of the deformable plate 440 is formed, the cross-sectional area of the conductive path is smaller than the portion where the groove 443B located on the outer peripheral side is formed, and the heat generated by energization tends to be larger. It is in. By making the width and depth of the opening of the groove 443B relatively large and the width and depth of the opening of the groove 443A relatively small, the cross-sectional area of the conductive path is promoted while promoting the desired deformation of the deformation plate 440. Can be suppressed from shrinking.

FIG. 17 is a cross-sectional view showing a state in which the deformed plate 440 is deformed and joined to the first positive electrode current collector 610.

As shown in FIG. 17, the deformed plate 440 is joined to the first positive electrode current collector 610 in a state in which the thick portion 441 is deformed so as to move to the sealing plate 120 side (lower side in the middle of FIG. 17). This deformation is caused by the introduction of gas pressure such as nitrogen gas into the conductive member 430 from the through hole 400A (see FIG. 8) provided in the positive electrode terminal 400.

The thick portion 441 approaching the sealing plate 120 side due to the above deformation of the deformed plate 440 is welded to the first positive electrode current collector 610. That is, the deformed plate 440 is joined to the first positive electrode current collector 610 in a state where stress in the direction of closing the openings of the grooves 443A and 443B is generated in the deformed plate 440.

Even in a structure in which the groove 443A and the groove 443B are not formed on the deformed plate 440, the deformed plate 440 is deformed so that the thick portion 441 located at the center of the deformed plate 440 moves toward the sealing plate 120, and the deformed plate 440 is the first positive electrode. It is joined to the current collector 610. However, the bonding strength between the deformed plate 440 and the first positive electrode current collector 610 may vary due to variations in the deformed state (shape after deformation, amount of deformation) of the deformed plate 440. As a result, the operation of the current cutoff mechanism 800 may become unstable.

On the other hand, in the deformed plate 440 according to the present embodiment, the groove 443A is formed on the upper surface of the A region located on the central side of the deformed plate 440, and on the lower surface of the B region located on the outer peripheral side of the deformed plate 440. Since the groove 443B is formed, the deformation in the direction shown in FIG. 17 is promoted, and the deformed shape of the deformed plate 440 is stabilized. Further, by closing the openings of the groove 443A and the groove 443B, further deformation is suppressed, so that the amount of deformation of the deformation plate 440 is stable. As described above, according to the deformed plate 440 according to the present embodiment, it is possible to suppress variations in the deformed state (shape after deformation, amount of deformation) of the deformed plate 440, so that the deformed plate 440 and the first positive electrode collection The bonding strength with the electric body 610 can be stabilized. As a result, the operation of the current cutoff mechanism 800 is stabilized.

Only one of the groove 443A and the groove 443B may be formed. In that case, it is preferable to form only the groove 443B on the outer peripheral side. The width and depth of the openings of the grooves 443A and 443B are preferably formed so that the gaps between the grooves are filled (the openings are closed) when the deformed plate 440 is deformed into a desired shape. When the deformed plate 440 is deformed into a desired shape, it may be formed so that a gap between the groove 443A and the groove 443B remains (the opening is not completely closed).

FIG. 18 is a diagram showing a modified example of the shape of the groove formed in the deformed plate 440. In the examples shown in FIGS. 12 to 17, a substantially V-shaped cross-sectional shape is shown, but instead of the substantially V-shaped cross-sectional shape, the groove 443C having a substantially U-shaped cross-sectional shape shown in FIG. 18 is used. May be done. The groove 443C has a cross-sectional shape in which the width of the opening is wider than the width of the bottom in a state where the deformed plate 440 is separated from the first positive electrode current collector 610, as in the case of a substantially V shape.

Further, instead of the above-mentioned perfect circular shape, a deformed plate 440 having a square planar shape may be used. In this case, the groove 443A and the groove 443B also extend in a square shape.

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, 100 battery case, 110 square exterior body, 120 sealing plate, 121 electrolyte injection hole, 122 sealing member, 123 gas discharge valve, 200 electrode body, 200A positive electrode plate, 200B negative electrode plate, 201 1 electrode body element, 202 second electrode body element, 210A positive electrode tab, 210B negative electrode tab, 211A first positive electrode tab group, 211B first negative electrode tab group, 212A second positive electrode tab group, 212B second negative electrode tab group, 213 welding Connection part, 220A main body part, 220B main body part, 230A positive electrode protective layer, 300 insulating sheet, 400 positive electrode terminal, 400A through hole, 410 external side insulating member, 420 insulating member, 430 conductive member, 431 conductive member base part, 432 tubular 433 Opening, 440 Deformed Plate, 500 Negative Electrode Terminal, 510 External Insulation Member, 600 Positive Electrode Collector, 610 First Positive Electrode Collector, 620 Second Positive Electrode Collector, 620A First Opening, 620B Second Opening, 630 Insulation member, 630A tubular part, 630B hole part, 631 connection part, 632 displacement prevention part, 700 negative electrode current collector, 710 first negative electrode current collector, 720 second negative electrode current collector, 720A first opening , 730 Insulation member, 800 current cutoff mechanism, 900 cover member.

Claims (20)

With the electrode body,
A battery case including an exterior body for accommodating the electrode body and a sealing plate for sealing the exterior body, and a battery case.
The terminal part attached to the sealing plate and
A conductive member connected to the terminal portion and having an opening on the electrode body side,
A deformed plate that seals the opening of the conductive member, and
It is provided with a current collector to be joined to the deformed plate.
The electrode body is electrically connected to the terminal portion via the current collector, the deformed plate, and the conductive member.
When the pressure in the battery case becomes a predetermined value or more, the deformation plate is deformed, and the electrical connection between the electrode body and the terminal portion is cut off.
The deformed plate has a first surface on the sealing plate side and a second surface on the electrode body side, and the deformed plate is further thickened in a region including the center thereof as compared with the surroundings. Has a large thick part,
On the first surface of the deformed plate, it is on the outer peripheral side of the thick portion, and the distance from the center of the deformed plate is more than half of the distance from the center to the outer peripheral edge of the deformed plate. A substantially annular groove is formed in a small area,
A battery in which the deformed plate is joined to the current collector in a state where stress in the direction of closing the opening of the groove is generated in the deformed plate. With the electrode body,
A battery case including an exterior body for accommodating the electrode body and a sealing plate for sealing the exterior body, and a battery case.
The terminal part attached to the sealing plate and
A conductive member connected to the terminal portion and having an opening on the electrode body side,
A deformed plate that seals the opening of the conductive member, and
It is provided with a current collector to be joined to the deformed plate.
The electrode body is electrically connected to the terminal portion via the current collector, the deformed plate, and the conductive member.
When the pressure in the battery case becomes a predetermined value or more, the deformation plate is deformed, and the electrical connection between the electrode body and the terminal portion is cut off.
The deformed plate has a first surface on the sealing plate side and a second surface on the electrode body side.
On the second surface of the deformed plate, a substantially annular groove is formed in a region where the distance from the center of the deformed plate is larger than half of the distance from the center to the outer peripheral edge of the deformed plate.
A battery in which the deformed plate is joined to the current collector in a state where stress in the direction of closing the opening of the groove is generated in the deformed plate. The groove has a depth of 1/3 or more and 1/2 or less of the total thickness of the deformed plate at the position where the groove is formed in a state where the deformed plate is separated from the current collector. Alternatively, the battery according to claim 2. The battery according to any one of claims 1 to 3, wherein the groove has a substantially V-shaped cross-sectional shape in a state where the deformed plate is separated from the current collector. With the electrode body,
A battery case including an exterior body for accommodating the electrode body and a sealing plate for sealing the exterior body, and a battery case.
The terminal part attached to the sealing plate and
A conductive member connected to the terminal portion and having an opening on the electrode body side,
A deformed plate that seals the opening of the conductive member, and
It is provided with a current collector to be joined to the deformed plate.
The electrode body is electrically connected to the terminal portion via the current collector, the deformed plate, and the conductive member.
When the pressure in the battery case becomes a predetermined value or more, the deformation plate is deformed, and the electrical connection between the electrode body and the terminal portion is cut off.
The deformed plate has a first surface on the sealing plate side and a second surface on the electrode body side, and the deformed plate is further thickened in a region including the center thereof as compared with the surroundings. Has a large thick part,
On the first surface of the deformed plate, it is on the outer peripheral side of the thick portion, and the distance from the center of the deformed plate is more than half of the distance from the center to the outer peripheral edge of the deformed plate. A substantially annular first groove is formed in the small first region,
On the second surface of the deformed plate, a substantially annular second groove is formed in a second region where the distance from the center of the deformed plate is larger than half of the distance from the center to the outer peripheral edge of the deformed plate. Being done
A battery in which the deformed plate is joined to the current collector in a state where stress in the direction of closing the openings of the first groove and the second groove is generated in the deformed plate. With the electrode body,
A battery case including an exterior body for accommodating the electrode body and a sealing plate for sealing the exterior body, and a battery case.
The terminal part attached to the sealing plate and
A conductive member connected to the terminal portion and having an opening on the electrode body side,
A deformed plate that seals the opening of the conductive member, and
It is provided with a current collector to be joined to the deformed plate.
The electrode body is electrically connected to the terminal portion via the current collector, the deformed plate, and the conductive member.
When the pressure in the battery case becomes a predetermined value or more, the deformation plate is deformed, and the electrical connection between the electrode body and the terminal portion is cut off.
The deformed plate has a first surface on the sealing plate side and a second surface on the electrode body side, and the deformed plate is further thickened in a region including the center thereof as compared with the surroundings. Has a large thick part,
On the first surface of the deformed plate, it is on the outer peripheral side of the thick portion, and the distance from the center of the deformed plate is more than half of the distance from the center to the outer peripheral edge of the deformed plate. A substantially annular first groove is formed in the small first region,
On the second surface of the deformed plate, a substantially annular second groove is formed in a second region where the distance from the center of the deformed plate is larger than half of the distance from the center to the outer peripheral edge of the deformed plate. Being done
The first groove and the second groove are batteries having a cross-sectional shape in which the width of the opening is wider than the width of the bottom in a state where the deformed plate is separated from the current collector. The battery according to claim 5 or 6, wherein the width of the opening of the first groove is narrower than the width of the opening of the second groove in a state where the deformed plate is separated from the current collector. The battery according to any one of claims 5 to 7, wherein the depth of the first groove is smaller than the depth of the second groove in a state where the deformed plate is separated from the current collector. The first groove and the second groove have a substantially V-shaped cross-sectional shape with the deformed plate separated from the current collector, according to any one of claims 5 to 8. battery. The battery according to any one of claims 1 to 9, wherein the deformed plate has a planar shape of a perfect circle or a square. The process of connecting the electrode body and the current collector,
The process of attaching the terminal and conductive member to the sealing plate of the battery case,
A step of preparing a deformed plate having a first surface and a second surface and having a thick portion having a thickness relatively larger than that of the surroundings formed in a region including the center thereof.
On the first surface of the deformed plate, it is on the outer peripheral side of the thick portion, and the distance from the center of the deformed plate is more than half of the distance from the center to the outer peripheral edge of the deformed plate. The process of forming a substantially annular groove in a small area,
With the first surface of the deformed plate facing the sealing plate side and the second surface of the deforming plate facing the electrode body side, the opening of the conductive member attached to the sealing plate is deformed. The process of sealing with a plate and
By joining the deformed plate and the current collector in a state where the deformed plate is deformed in the direction of closing the opening of the groove, the electrode is passed through the current collector, the deformed plate, and the conductive member. The process of electrically connecting the body to the terminal and
A method for manufacturing a battery, comprising a step of accommodating the electrode body in an exterior body and sealing the exterior body with the sealing plate. The process of connecting the electrode body and the current collector,
The process of attaching the terminal and conductive member to the sealing plate of the battery case,
A step of preparing a deformed plate having a first surface and a second surface and having a thick portion having a thickness relatively larger than that of the surroundings formed in a region including the center thereof.
A step of forming a substantially annular groove on the second surface of the deformed plate in a region where the distance from the center of the deformed plate is larger than half of the distance from the center to the outer peripheral edge of the deformed plate.
With the first surface of the deformed plate facing the sealing plate side and the second surface of the deforming plate facing the electrode body side, the opening of the conductive member attached to the sealing plate is deformed. The process of sealing with a plate and
By joining the deformed plate and the current collector in a state where the deformed plate is deformed in the direction of closing the opening of the groove, the electrode is passed through the current collector, the deformed plate, and the conductive member. The process of electrically connecting the body to the terminal and
A method for manufacturing a battery, comprising a step of accommodating the electrode body in an exterior body and sealing the exterior body with the sealing plate. 11. The groove has a depth of 1/3 or more and 1/2 or less of the total thickness of the deformed plate at the position where the groove is formed in a state where the deformed plate is separated from the current collector. Alternatively, the method for manufacturing a battery according to claim 12. The method for manufacturing a battery according to any one of claims 11 to 13, wherein the groove has a substantially V-shaped cross-sectional shape in a state where the deformed plate is separated from the current collector. The process of connecting the electrode body and the current collector,
The process of attaching the terminal and conductive member to the sealing plate of the battery case,
A step of preparing a deformed plate having a first surface and a second surface and having a thick portion having a thickness relatively larger than that of the surroundings formed in a region including the center thereof.
On the first surface of the deformed plate, it is on the outer peripheral side of the thick portion, and the distance from the center of the deformed plate is more than half of the distance from the center to the outer peripheral edge of the deformed plate. A step of forming a substantially annular first groove in a small first region,
On the second surface of the deformed plate, a substantially annular second groove is formed in a second region where the distance from the center of the deformed plate is larger than half of the distance from the center to the outer peripheral edge of the deformed plate. And the process to do
With the first surface of the deformed plate facing the sealing plate side and the second surface of the deforming plate facing the electrode body side, the opening of the conductive member attached to the sealing plate is deformed. The process of sealing with a plate and
By joining the deformed plate and the current collector in a state where the deformed plate is deformed in a direction of closing the openings of the first groove and the second groove, the current collector, the deformed plate, and the said The process of electrically connecting the electrode body and the terminal portion via a conductive member, and
A method for manufacturing a battery, comprising a step of accommodating the electrode body in an exterior body and sealing the exterior body with the sealing plate. The process of connecting the electrode body and the current collector,
The process of attaching the terminal and conductive member to the sealing plate of the battery case,
A step of preparing a deformed plate having a first surface and a second surface and having a thick portion having a thickness relatively larger than that of the surroundings formed in a region including the center thereof.
On the first surface of the deformed plate, it is on the outer peripheral side of the thick portion, and the distance from the center of the deformed plate is more than half of the distance from the center to the outer peripheral edge of the deformed plate. A step of forming a substantially annular first groove having a cross-sectional shape in which the width of the opening is wider than the width of the bottom in the small first region.
On the second surface of the deformed plate, the opening is larger than the width of the bottom in the second region where the distance from the center of the deformed plate is larger than half the distance from the center to the outer peripheral edge of the deformed plate. A step of forming a substantially annular second groove having a wide cross-sectional shape,
With the first surface of the deformed plate facing the sealing plate side and the second surface of the deforming plate facing the electrode body side, the opening of the conductive member attached to the sealing plate is deformed. The process of sealing with a plate and
A step of electrically connecting the electrode body and the terminal portion via the current collector, the deformed plate, and the conductive member by joining the deformed plate and the current collector.
A method for manufacturing a battery, comprising a step of accommodating the electrode body in an exterior body and sealing the exterior body with the sealing plate. The method for manufacturing a battery according to claim 15 or 16, wherein the width of the opening of the first groove is narrower than the width of the opening of the second groove in a state where the deformed plate is separated from the current collector. The manufacture of the battery according to any one of claims 15 to 17, wherein the depth of the first groove is smaller than the depth of the second groove in a state where the deformed plate is separated from the current collector. Method. The first groove and the second groove have a substantially V-shaped cross-sectional shape with the deformed plate separated from the current collector, according to any one of claims 15 to 18. How to make a battery. The method for manufacturing a battery according to any one of claims 11 to 19, wherein the deformed plate has a planar shape of a perfect circle or a square.

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