Battery and method for manufacturing a battery

Abstract

Disclosed is a battery provided with: an electrode group of a jelly-roll type, having a first electrode (21), a second electrode, and a separator, each of which is in a band shape; and a first current collecting plate (60) electrically connected to the first electrode (21). The first electrode (21) has at least one first portion (24) welded to the first current collecting plate (60), and at least one second portion (25) located next to the at least one first portion (24) in a radial direction of the electrode group and separated from the first current collecting plate (60).

Description

[0001] Cross-reference of related applications

[0002] This disclosure claims priority to Japan Patent Application No. 2024-048329, filed on March 25, 2024, the contents of which are incorporated herein by reference in their entirety. Technical Field

[0003] This disclosure relates to batteries and methods for manufacturing batteries. Background Technology

[0004] Previously, a battery was known to have a wound electrode assembly consisting of a first electrode, a second electrode, and a separator, and a current collector electrically connected to the first electrode (e.g., Patent Document 1). Patent Document 1 discloses: "A cylindrical battery comprising: a wound electrode body formed by winding at least one first electrode plate and at least one second electrode plate through a separator; a bottomed cylindrical outer can for housing the electrode body; and a first terminal electrode mounted on the opening of the outer can through a first insulating member to block the opening of the outer can, wherein the first electrode plate has a first core formed of a conductive material and a first active material layer formed on the first core, a side portion of the first terminal electrode of the first core electrode is led out from the side portion of the first active material layer to form a first lead-out portion, the first lead-out portion including a first bend portion bending toward the inner or outer peripheral side of the electrode body, a first surface of a first current collector plate contacting the side surface of the first terminal electrode of the first bend portion, and the first terminal electrode being directly or via a conductive member connected to a second surface of the first current collector plate."

[0005] Prior art literature

[0006] Patent documents

[0007] Patent Document 1: International Publication No. 2019 / 194182 Summary of the Invention

[0008] -The problem the invention aims to solve-

[0009] The first electrode and the current collector of the electrode assembly are sometimes connected by welding. During this welding process, sometimes a portion of the first electrode melts and adheres to another portion of the first electrode, resulting in a state where tiny metallic foreign objects are attached to that other portion. Such metallic foreign objects are relatively easy to detach, raising concerns about the potential for internal short circuits in the battery. In such cases, this disclosure aims to suppress internal short circuits as one of its objectives.

[0010] -Methods for solving problems-

[0011] One aspect of this disclosure relates to a battery. The battery comprises: a wound electrode assembly having a strip-shaped first electrode, a second electrode, and a separator; and a first current collector electrically connected to the first electrode, the first electrode having: at least one first portion welded to the first current collector; and at least one second portion located radially adjacent to the at least one first portion and separated from the first current collector in the electrode assembly.

[0012] Another aspect of this disclosure relates to a method for manufacturing a battery. The manufacturing method for manufacturing the battery described above includes: a laser cutting step, in which a portion of the first electrode corresponding to the at least one second portion is cut using a laser; and a winding step, in which the cut first electrode, the second electrode, and the spacer are wound together to form the electrode assembly.

[0013] -Invention Effects-

[0014] According to this disclosure, internal short circuits can be suppressed.

[0015] The novel features of the present invention are described in the appended technical solutions, but the present invention will be further fully understood in terms of both structure and content, in conjunction with other objects and features of the present invention, through the following detailed description with reference to the accompanying drawings. Attached Figure Description

[0016] Figure 1 This is a schematic longitudinal sectional view illustrating an example of the battery involved in this disclosure.

[0017] Figure 2 It is a schematic top view showing the first electrode and the first collector plate of the electrode assembly. The first part is shown with solid lines, the second part with dashed lines, and the first collector plate with double-dotted lines.

[0018] Figure 3 This is a schematic cross-sectional view showing the connection between the first electrode and the first collector plate, corresponding to... Figure 2 Line III-III. Detailed Implementation

[0019] The following describes embodiments of the battery and battery manufacturing method involved in this disclosure by way of example. However, this disclosure is not limited to the examples described below. In the following description, specific values ​​and materials are sometimes illustrated, but other values ​​and materials may be applied as long as the effects of this disclosure can be obtained.

[0020] (Battery)

[0021] The batteries disclosed herein can be primary batteries such as lithium primary batteries, or secondary batteries such as alkaline batteries (nickel-metal hydride batteries, nickel-cadmium batteries, etc.), lithium-ion secondary batteries, lithium metal secondary batteries, etc. In this disclosure, energy storage devices (e.g., lithium-ion capacitors, electric double-layer capacitors) in which at least one of the positive and negative electrodes exhibits capacity through a non-Radida reaction are also included in the scope of batteries. The batteries disclosed herein include an electrode assembly and a first current collector.

[0022] The electrode assembly has a first electrode and a second electrode, which are respectively in the form of a strip (or a long sheet), and a spacer. The electrode assembly is formed by winding the first electrode and the second electrode together with the spacer in between. In other words, the electrode assembly is a wound type electrode assembly having a first electrode, a second electrode, and a spacer between the two electrodes. The electrode assembly is cylindrical in shape, for example, it can be cylindrical or prismatic. One of the first electrode and the second electrode is the positive electrode, and the other of the first electrode and the second electrode is the negative electrode.

[0023] The first electrode may also have a strip-shaped first current collector and a first active material layer supported on the first current collector. The second electrode may also have a strip-shaped second current collector and a second active material layer supported on the second current collector. The separator may also be made of a porous sheet material that is both ion-permeable and insulating. Examples of porous sheets include microporous films, woven fabrics, and nonwoven fabrics.

[0024] The following explanation uses a lithium-ion battery as an example. The first active material layer can be disposed on both sides of the first current collector, or on only one side of the first current collector. When the first electrode is a positive electrode, the first current collector is a positive current collector (e.g., it can be made of aluminum foil or aluminum alloy foil), and the first active material layer is a positive active material layer (e.g., it can contain a lithium-containing transition metal oxide). When the first electrode is a negative electrode, the first current collector is a negative current collector (e.g., it can be made of copper foil or copper alloy foil), and a negative active material layer (e.g., it can contain a carbonaceous material) can be disposed as the first active material layer.

[0025] The first current collector is electrically connected to the first electrode of the electrode group. When the first electrode is positive, the first current collector is a positive current collector (e.g., it can be made of stainless steel, titanium, titanium alloy, aluminum, or aluminum alloy). When the first electrode is negative, the first current collector is a negative current collector (e.g., it can be made of nickel, nickel alloy, copper, or copper alloy). The first current collector can also be electrically connected to the first electrode by any type of welding (e.g., laser welding or resistance welding). A plating treatment to improve weldability (e.g., lead-tin plating, nickel-tin plating, zinc-nickel plating, chromium plating, zinc plating, nickel plating, etc.) can also be applied to the surface of the first current collector.

[0026] The first electrode has at least one first portion and at least one second portion. At least one first portion is welded to a first current collector. At least one second portion is located radially (hereinafter also simply referred to as radial) next to at least one first portion and separated from the first current collector. That is, at least one first portion is welded to the first current collector, while at least one second portion is not welded to the first current collector. The weld between at least one first portion and the first current collector may also extend radially. Because at least one second portion separated from the first current collector exists next to at least one first portion, even if a portion of the first portion melts when at least one first portion is welded to the first current collector, it is difficult for it to adhere to the adjacent second portion. Therefore, it is difficult to generate metallic foreign matter that could be a cause of internal short circuits, and internal short circuits in the battery can be suppressed.

[0027] The first electrode may also have a strip-shaped first current collector and a first active material layer supported on the first current collector. The first current collector may also have a first exposed portion exposed from the first active material layer. In other words, the first current collector may also have: a first covered portion supporting the first active material layer and a first exposed portion not supporting the first active material layer. The first exposed portion may also be disposed at one end in the short side direction (or, in the winding axis direction of the electrode assembly) of the first current collector. At least one first portion and at least one second portion may also be included in the first exposed portion. In this structure, in the second portion, the first active material layer is not removed, thus enabling the battery capacity to be maintained at a high level. However, at least one second portion may also be included in the portion of the first current collector in which the first active material layer is disposed.

[0028] At least one first part may also have a bent portion welded to the surface of the first current collector. This reduces the connection resistance between at least one first part and the first current collector, i.e., the connection resistance between the first electrode and the first current collector, thereby reducing the internal resistance of the battery. Such a bent portion can also be formed using a given tool (e.g., a roller) after the first electrode, the second electrode, and the separator are wound. The bent portion can also be formed by bending a portion of the first part radially inward. However, at least one first part may not have such a bent portion.

[0029] At least one first part may also comprise multiple first parts. At least one second part may also comprise multiple second parts. In at least a portion of the first electrode, multiple first parts and multiple second parts may also be arranged alternately in the radial direction. In this case, the effects of the technology involved in this disclosure can be obtained, while reducing the connection resistance between the first electrode and the first collector plate. Furthermore, multiple first parts and multiple second parts may also be arranged in any order in the radial direction.

[0030] The battery may also include a second current collector electrically connected to the second electrode. The second electrode may also have at least one third portion welded to the second current collector, and at least one fourth portion radially adjacent to the third portion and separated from the second current collector. That is, in this structure, the same relationship as that between the first electrode and the first current collector applies between the second electrode and the second current collector. Therefore, the effects of the technology disclosed herein can also be obtained between the second electrode and the second current collector. Furthermore, the battery may not have a second current collector; in this case, electrode leads may be connected to the second electrode.

[0031] The second electrode may also have a strip-shaped second current collector and a second active material layer supported on the second current collector. The second current collector may also have a second exposed portion protruding from the second active material layer. In other words, the second current collector may also have: a second covered portion supporting the second active material layer, and a second exposed portion not supporting the second active material layer. The second exposed portion may also be disposed at one end in the short side direction (or, in the winding axis direction of the electrode assembly) of the second current collector. At least one third portion and at least one fourth portion may also be included in the second exposed portion. In this structure, the second active material layer is not removed in the fourth portion, thus enabling the battery capacity to be maintained at a higher level. However, at least one fourth portion may also be included in the portion of the second current collector in which the second active material layer is disposed.

[0032] The first electrode can also be the negative electrode of a lithium-ion secondary battery or a lithium metal secondary battery. The first current collector can also be made of a material containing iron or copper. In this structure, the second electrode is the positive electrode, and if the battery has a second current collector, the second current collector can also be made of a material containing aluminum.

[0033] The first electrode can also be the positive electrode of a lithium-ion secondary battery or a lithium metal secondary battery. The first current collector can also be made of a material containing aluminum. In this structure, the second electrode is the negative electrode. If the battery has a second current collector, the second current collector can also be made of a material containing iron or copper.

[0034] (Battery manufacturing method)

[0035] The battery manufacturing method disclosed herein includes a laser cutting process and a winding process.

[0036] In the laser cutting process, a laser is used to cut the portion of the first electrode that corresponds to at least one second portion. The portion corresponding to the second portion may be rectangular in the unfolded state of the first electrode, but is not limited to this.

[0037] In the winding process, the cut first electrode, second electrode, and spacer are wound together to form an electrode assembly. This results in an electrode assembly having a first electrode comprising at least one first portion and at least one second portion. The winding process can also be performed after the laser cutting process.

[0038] The battery manufacturing method may also include a laser welding process in which at least one first part and a first current collector are welded together by laser. In the laser welding process, at least one first part and a first current collector can also be welded by scanning the laser along the radial direction of the electrode assembly.

[0039] As described above, according to this disclosure, by providing at least one second portion separated from the first collector board, internal short circuits of the battery can be suppressed.

[0040] Hereinafter, an example of a battery and a method for manufacturing a battery according to this disclosure will be specifically described with reference to the accompanying drawings. The aforementioned components and processes can be applied to the components and processes of the battery and the method for manufacturing a battery in the example described below. The components and processes of the battery and the method for manufacturing a battery in the example described below can be modified based on the above description. Furthermore, the matters described below can also be applied to the above-described embodiments. Components and processes in the components and processes of the battery and the method for manufacturing a battery in the example described below that are not essential to the battery and the method for manufacturing a battery according to this disclosure can be omitted. In addition, the figures shown below are schematic and do not accurately reflect the actual shape and number of components.

[0041] (Battery)

[0042] The battery 10 in this embodiment is configured as a lithium-ion secondary battery, but it is not limited to this. Figures 1-3 As shown, the battery 10 includes: a wound electrode assembly 20, a first current collector 60, a second current collector 70, a housing 40, and a sealing plate 51.

[0043] The electrode assembly 20 is formed by winding a strip-shaped first electrode 21 and a second electrode 26 through a strip-shaped spacer 32. In this embodiment, the first electrode 21 is the positive electrode and the second electrode 26 is the negative electrode, but this is not a limitation. The spacer 32 is exposed at the outermost periphery of the electrode assembly 20, but this is not a limitation. For example, the first current collector 22 or the second current collector 27 (described later) may also be exposed at the outermost periphery of the electrode assembly 20.

[0044] The first electrode 21 has a strip-shaped first current collector 22 and a first active material layer (not shown) disposed on the surface of the first current collector 22. In this embodiment, the first active material layer is disposed on both sides of the first current collector 22, but it is not limited thereto. The first current collector 22 is, for example, made of aluminum foil or aluminum alloy foil.

[0045] The first current collector 22 has: a first exposed portion 23, located at one end in a direction orthogonal to its long side direction ( Figure 1 The first exposed portion 23 has a plurality of first portions 24 welded to the first current collector 60, and a plurality of second portions 25 located radially adjacent to the plurality of first portions 24 and separated from the first current collector 60 in the electrode assembly 20. In this embodiment, the plurality of first portions 24 have bent portions 24a welded to the surface of the first current collector 60, but this is not a limitation. In this embodiment, the plurality of first portions 24 and the plurality of second portions 25 are arranged alternately in the radial direction in at least a portion of the first exposed portion 23, but this is not a limitation.

[0046] The second electrode 26 has a strip-shaped second current collector 27. In this embodiment, the second electrode 26 also has a second active material layer (not shown) disposed on the surface of the second current collector 27, but is not limited thereto. The second current collector 27 is, for example, made of copper foil or copper alloy foil.

[0047] The second current collector 27 has: a second exposed portion 28, located at one end in a direction orthogonal to its long side direction ( Figure 1 The second exposed portion 28 has a plurality of third portions 29 welded to the second current collector 70, and a plurality of fourth portions 31 located radially adjacent to the plurality of third portions 29 and separated from the second current collector 70 in the electrode assembly 20. In this embodiment, the plurality of third portions 29 have bends 29a welded to the surface of the second current collector 70, but this is not a limitation. In this embodiment, the plurality of third portions 29 and the plurality of fourth portions 31 are arranged alternately in the radial direction in at least a portion of the second exposed portion 28, but this is not a limitation.

[0048] The first current collector 60 is connected to the first exposed portion 23 by welding and is electrically connected to the first current collector 22. The first current collector 60 is made of a material containing aluminum (e.g., aluminum, aluminum alloy). The first current collector 60 is generally cross-shaped as a whole and has a plurality of (in this example, four) arms 61.

[0049] The second collector plate 70 is connected to the second exposed portion 28 by welding and is electrically connected to the second collector body 27. The second collector plate 70 is made of, for example, a material containing iron (e.g., stainless steel) or a material containing copper (e.g., copper, copper alloy). The second collector plate 70 is generally cross-shaped as a whole and has multiple (in this example, four) arms (not shown).

[0050] The housing 40 is made of metal and is formed at one end ( Figure 1 The upper end of the housing 40 is a bottomed cylindrical shape with an opening. A welding member 41 is provided on the inner bottom surface of the housing 40, and the second current collector 70 is welded to the welding member 41. Therefore, the housing 40 of this embodiment functions as an external negative terminal.

[0051] The sealing plate 51 seals the opening of the housing 40. A gasket 52 is fitted around the periphery of the sealing plate 51, and the interior of the housing 40 is sealed by riveting the opening end of the housing 40 to the gasket. The sealing plate 51 is electrically connected to the first current collector 60 via a metal tab 53. Therefore, the sealing plate 51 in this embodiment functions as an external positive terminal.

[0052] (Battery manufacturing method)

[0053] The battery manufacturing method of this embodiment is a method for manufacturing the battery 10 described above, and includes a laser cutting process, a winding process, and a laser welding process.

[0054] In the laser cutting process, the portions of the first exposed portion 23 corresponding to the plurality of second portions 25 are cut off by a laser. Additionally, in the laser cutting process, the portions of the second exposed portion 28 corresponding to the plurality of fourth portions 31 are cut off by a laser.

[0055] In the laser cutting process, whenever the portion of the first electrode 21 corresponding to at least one second portion 25 is cut, the area where the first active material layer is disposed can also be cut, in addition to the first exposed portion 23. Furthermore, in the laser cutting process, whenever the portion of the second electrode 26 corresponding to at least one fourth portion 31 is cut, the area where the second active material layer is disposed can also be cut, in addition to the second exposed portion 28.

[0056] In the winding process, the cut first electrode 21, the cut second electrode 26 and the separator 32 are wound together to form an electrode group 20.

[0057] In the laser welding process, multiple first parts 24 and first collector boards 60 are welded together using a laser. Additionally, in the laser welding process, multiple third parts 29 and second collector boards 70 are welded together using a laser.

[0058] Postscript

[0059] The following technology has been disclosed through the above description of the embodiments.

[0060] (Technology 1)

[0061] A battery having:

[0062] A wound electrode assembly has a first electrode, a second electrode, and an insulating element, each in the form of a strip; and

[0063] The first collector plate is electrically connected to the first electrode.

[0064] The first electrode has:

[0065] At least one first part is soldered to the first current collector; and

[0066] At least one second part is located radially adjacent to the at least one first part of the electrode group and separated from the first current collector.

[0067] (Technology 2)

[0068] In the battery described in Technique 1

[0069] The first electrode has: a strip-shaped first current collector and a first active material layer supported on the first current collector.

[0070] The first current collector has: a first exposed portion, exposed from the first active material layer,

[0071] The at least one first portion and the at least one second portion are contained within the first exposed portion.

[0072] (Technology 3)

[0073] In the battery described in technique 1 or 2

[0074] The at least one first part has: a bent portion, which is welded to the surface of the first current collector.

[0075] (Technology 4)

[0076] In any of the batteries described in techniques 1 to 3,

[0077] The at least one first part comprises a plurality of first parts.

[0078] The at least one second part comprises a plurality of second parts.

[0079] At least a portion of the first electrode, the plurality of first portions and the plurality of second portions are alternately arranged in the radial direction.

[0080] (Technology 5)

[0081] In any of the batteries described in techniques 1 to 4,

[0082] The battery also includes: a second current collector, electrically connected to the second electrode.

[0083] The second electrode has:

[0084] At least one third part is soldered to the second current collector; and

[0085] At least one fourth part is located in the radial direction next to the at least one third part and separated from the second collector plate.

[0086] (Technology 6)

[0087] In the battery described in Technique 5

[0088] The second electrode has: a strip-shaped second current collector and a second active material layer supported on the second current collector.

[0089] The second current collector has a second exposed portion that protrudes from the second active material layer.

[0090] The at least third part and the at least fourth part are contained within the second exposed portion.

[0091] (Technology 7)

[0092] In any of the batteries described in techniques 1 to 6,

[0093] The first electrode is the negative electrode of a lithium-ion secondary battery or a lithium metal secondary battery.

[0094] The first collector plate is made of a material containing iron or copper.

[0095] (Technology 8)

[0096] In any of the batteries described in techniques 1 to 6,

[0097] The first electrode is the positive electrode of a lithium-ion secondary battery or a lithium metal secondary battery.

[0098] The first collector plate is made of a material containing aluminum.

[0099] (Technology 9)

[0100] A method for manufacturing a battery, comprising the battery described in any one of techniques 1 to 8.

[0101] The method for manufacturing the battery comprises:

[0102] The laser cutting process involves using a laser to cut the portion of the first electrode corresponding to at least one second portion; and

[0103] The winding process involves winding the cut first electrode, the second electrode, and the insulating member to form the electrode assembly.

[0104] (Technology 10)

[0105] In the battery manufacturing method described in Technique 9,

[0106] The battery manufacturing method further includes a laser welding process, in which at least one first part and the first current collector are welded together by laser.

[0107] Industrial availability

[0108] This disclosure can be used in batteries and methods of manufacturing batteries.

[0109] The present invention has been described with reference to preferred embodiments at the present point in time, but such disclosure is not intended to be limiting. Various modifications and alterations will be clear and obvious to those skilled in the art upon reading the above disclosure. Therefore, the appended technical solutions should be interpreted as encompassing all modifications and alterations without departing from the true spirit and scope of the invention.

[0110] -Explanation of Figure Markers-

[0111] 10: Battery

[0112] 20: Electrode assembly

[0113] 21: Electrode 1

[0114] 22: First collector

[0115] 23: First exposed part

[0116] 24: Part 1

[0117] 24a: Bending section

[0118] 25: Part 2

[0119] 26: Second electrode

[0120] 27: Second collector

[0121] 28: Second exposed part

[0122] 29: Part 3

[0123] 29a: Bending section

[0124] 31: Part 4

[0125] 32: Isolation component

[0126] 40: Shell

[0127] 41: Welding components

[0128] 51: Sealing plate

[0129] 52: Padding

[0130] 53: Metal tabs

[0131] 60: First collector board

[0132] 61: Arm

[0133] 70: Second collector board.

Claims

1. A battery, comprising: A wound electrode assembly has a first electrode, a second electrode, and an insulating element, each in the form of a strip; and The first collector plate is electrically connected to the first electrode. The first electrode has: At least one first part is soldered to the first current collector; and At least one second part is located radially adjacent to the at least one first part of the electrode group and separated from the first current collector.

2. The battery according to claim 1, wherein, The first electrode has: a strip-shaped first current collector and a first active material layer supported on the first current collector. The first current collector has: a first exposed portion, exposed from the first active material layer, The at least one first portion and the at least one second portion are contained within the first exposed portion.

3. The battery according to claim 1 or 2, wherein, The at least one first part has: a bent portion, which is welded to the surface of the first current collector.

4. The battery according to claim 1 or 2, wherein, The at least one first part comprises a plurality of first parts. The at least one second part comprises a plurality of second parts. At least a portion of the first electrode, the plurality of first portions and the plurality of second portions are alternately arranged in the radial direction.

5. The battery according to claim 1 or 2, wherein, The battery also includes: a second current collector, electrically connected to the second electrode. The second electrode has: At least one third part is soldered to the second current collector; and At least one fourth part is located in the radial direction next to the at least one third part and separated from the second collector plate.

6. The battery according to claim 5, wherein, The second electrode has: a strip-shaped second current collector and a second active material layer supported on the second current collector. The second current collector has a second exposed portion that protrudes from the second active material layer. The at least third part and the at least fourth part are contained within the second exposed portion.

7. The battery according to claim 1 or 2, wherein, The first electrode is the negative electrode of a lithium-ion secondary battery or a lithium metal secondary battery. The first collector plate is made of a material containing iron or copper.

8. The battery according to claim 1 or 2, wherein, The first electrode is the positive electrode of a lithium-ion secondary battery or a lithium metal secondary battery. The first collector plate is made of a material containing aluminum.

9. A method for manufacturing a battery, comprising manufacturing the battery according to claim 1 or 2. The method for manufacturing the battery comprises: The laser cutting process involves using a laser to cut the portion of the first electrode corresponding to at least one second portion; and The winding process involves winding the cut first electrode, the second electrode, and the insulating member to form the electrode assembly.

10. The method for manufacturing a battery according to claim 9, wherein, The battery manufacturing method further includes a laser welding process, in which at least one first part and the first current collector are welded together by laser.

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