Method for manufacturing power storage element, and power storage element

Abstract

This method for manufacturing a power storage element comprises inserting an electrode body into a case body having an opening, wherein in the insertion of the electrode body, a rolling element is disposed between the electrode body and the case body. This power storage element comprises: an electrode body; a case body having an opening and accommodating the electrode body; and a rolling element disposed between the electrode body and the case body.

Description

Method for manufacturing a storage element and storage element

[0001] The present invention relates to a method for manufacturing a storage element including an electrode body in which electrodes are laminated, and a storage element. This application claims priority based on Japanese Patent Application No. 2024-225765 filed on December 20, 2024, and the content thereof is incorporated herein by reference.

[0002] Patent Document 1 discloses a flat wound secondary battery in which an electrode group is housed in a flat cylindrical battery can.

[0003] Japanese Patent Application Laid-Open No. 2013-161555

[0004] When manufacturing a flat wound secondary battery, the electrode group may be deformed when the electrode group is inserted into the battery can, making it difficult to insert the electrode group into the battery can.

[0005] Aspects of the present invention provide a method for manufacturing a storage element and a storage element in which insertion of the electrode body into the case body is easy.

[0006] The method for manufacturing a storage element according to this embodiment includes inserting an electrode body into a case body having an opening, and a rolling element is disposed between the electrode body and the case body during the insertion of the electrode body.

[0007] The storage element according to this embodiment includes an electrode body, a case body having an opening and housing the electrode body, and a rolling element disposed between the electrode body and the case body.

[0008] According to this embodiment, it is possible to provide a method for manufacturing a storage element and a storage element in which insertion of the electrode body into the case body is easy.

[0009] FIG. 1 is a view of the storage element according to this embodiment as seen from the Y-axis direction. FIG. 2 is an exploded perspective view of the storage element. FIG. 3 is a view of the electrode body included in the storage element as seen from the X-axis direction. FIG. 4 is a view of the electrode laminate included in the electrode body as seen from the X-axis direction. FIG. 5 is a flowchart of the method for manufacturing the storage element. FIG. 6 is a perspective view showing a state in which the electrode body is inserted into the case body.

[0010] (1) A method for manufacturing an energy storage element according to one embodiment of the present invention comprises inserting an electrode body into a case body having an opening, wherein a rolling element is arranged between the electrode body and the case body during the insertion of the electrode body.

[0011] According to the manufacturing method of an energy storage element according to one embodiment of the present invention, the rolling element rolls between the electrode body and the case body, making it easier to insert the electrode body into the case body.

[0012] (2) In the method for manufacturing the energy storage element described in (1) above, the rolling element may be spherical.

[0013] According to the manufacturing method of the energy storage element described in (2) above, when inserting the electrode body into the case body, the rolling elements can roll more easily between the electrode body and the case body, making it easier to insert the electrode body into the case body.

[0014] (3) In the method for manufacturing an energy storage element described in (1) or (2) above, the rolling element may be an inorganic particle.

[0015] According to the method for manufacturing the energy storage element described in (3) above, since the rolling elements are inorganic particles, the influence of the rolling elements on the charging and discharging of the energy storage element is suppressed.

[0016] (4) A storage element according to another embodiment of the present invention comprises an electrode body, a case body having an opening and housing the electrode body, and rolling elements disposed between the electrode body and the case body.

[0017] According to another embodiment of the energy storage element of the present invention, when the electrode body is inserted into the case body, the rolling element rolls between the electrode body and the case body, making it easier to insert the electrode body into the case body.

[0018] (5) In the energy storage element described in (4) above, the rolling element may be spherical.

[0019] According to the energy storage element described in (5) above, when inserting the electrode into the case body, the rolling elements can roll more easily between the electrode and the case body, making it easier to insert the electrode into the case body.

[0020] (6) In the energy storage element described in (4) or (5) above, the rolling element may be an inorganic particle.

[0021] According to the energy storage element described in (6) above, since the rolling elements are inorganic particles, the influence of the rolling elements on the charging and discharging of the energy storage element is suppressed.

[0022] Hereinafter, one embodiment of the present invention will be described with reference to Figures 1 to 6. Note that the names of each component (each element) in this embodiment are those of this embodiment and may differ from the names of each component (each element) in the background art.

[0023] Energy storage elements include primary batteries, secondary batteries, and capacitors. In this embodiment, a rechargeable secondary battery will be described as an example of an energy storage element.

[0024] The energy storage element in this embodiment is a non-aqueous electrolyte secondary battery. More specifically, the energy storage element is a lithium-ion secondary battery that utilizes electron transfer that occurs with the movement of lithium ions. This type of energy storage element supplies electrical energy. The energy storage element is used individually or in combination with other elements. Specifically, the energy storage element is used individually when the required output and voltage are small. On the other hand, when at least one of the required output and voltage is large, the energy storage element is used in combination with other energy storage elements in an energy storage device. In the energy storage device, the energy storage elements used in the device supply electrical energy.

[0025] Specifically, as shown in Figures 1 and 2, the energy storage element 1 comprises an electrode body 2, a case 3 housing the electrode body 2, and terminals 4 that conduct electricity between the inside and outside of the case 3 and are exposed to the outside of the case 3. Furthermore, the energy storage element 1 of this embodiment includes rolling elements 5 arranged between the electrode body 2 and the case 3 (see Figure 6).

[0026] As shown in Figure 3, the electrode body 2 comprises an electrode stack 21 in which electrodes are stacked, and a covering member 26 that covers the electrode stack 21.

[0027] The electrode stack 21 comprises wound electrodes. In this embodiment, the electrode stack 21 comprises flatly wound electrodes. In this electrode stack 21, the electrodes include a positive electrode and a negative electrode, and these positive and negative electrodes are stacked in a state where they are insulated from each other. In the electrode stack 21, lithium ions move between the positive and negative electrodes, causing the energy storage element 1 to charge and discharge. In the following description, the direction in which the winding axis C of the electrode stack 21 extends is defined as the X-axis direction in the Cartesian coordinate system, the minor axis direction of the electrode stack 21 is defined as the Y-axis direction in the Cartesian coordinate system, and the major axis direction of the electrode stack 21 is defined as the Z-axis direction in the Cartesian coordinate system.

[0028] As shown in Figure 4, the electrode stack 21 has a flat portion 211 that extends in the Z-axis direction when viewed from the X-axis direction, and a pair of curved portions 212 that are positioned at both ends of the flat portion 211 in the Z-axis direction when viewed from the X-axis direction.

[0029] The flat portion 211 is a part of the electrode stack 21 in which electrodes extending in a planar direction including the X-axis and Z-axis directions are stacked in the Y-axis direction.

[0030] The curved portion 212 is a region where electrodes, which are curved so as to be convex in a direction away from the flat portion 211 when viewed from the X-axis direction, are stacked in the Z-axis direction.

[0031] The positive electrode comprises a strip-shaped metal foil and a positive electrode active material layer superimposed on the metal foil. This positive electrode active material layer is superimposed on the metal foil with one edge (uncovered portion) in the width direction of the metal foil exposed. In this embodiment, the metal foil is, for example, aluminum foil.

[0032] The negative electrode comprises a strip-shaped metal foil and a negative electrode active material layer superimposed on the metal foil. This negative electrode active material layer is superimposed on the metal foil with the other edge (uncoated portion) in the width direction of the metal foil (opposite the uncoated portion of the positive electrode metal foil) exposed. In this embodiment, the metal foil is, for example, copper foil.

[0033] In the electrode stack 21 of this embodiment, the positive electrode and the negative electrode are wound together in an insulated state by a separator. That is, in the electrode stack 21 of this embodiment, the positive electrode, the negative electrode, and the separator are wound together in a stacked state.

[0034] The separator is an insulating component and is placed between the positive and negative electrodes. This insulates the positive and negative electrodes from each other in the electrode stack 21. The separator also holds the electrolyte within the case 3. This allows lithium ions to move between the positive and negative electrodes, which are stacked alternately with the separator in between, during charging and discharging of the energy storage element 1. The separator is strip-shaped and is made of a porous membrane such as polyethylene, polypropylene, cellulose, or polyamide.

[0035] The covering member 26 electrically insulates the electrode laminate 21 from the case 3 by surrounding the electrode laminate 21 in the circumferential direction. The covering member 26 is an insulating and flexible sheet-like material (see Figure 3). This covering member 26 surrounds the electrode laminate 21 in the circumferential direction (in other words, in the winding direction of the electrodes). In this embodiment, the covering member 26 is insulating and is formed of a polyolifene-based resin film such as polypropylene or polyethylene.

[0036] Case 3, as shown in Figures 1 and 2, is a rectangular parallelepiped or cubic shape of a size corresponding to the electrode body 2, and the electrode body 2 is housed in such a way that the winding axis C of the electrode stack 21 is aligned with the opposing direction (in this embodiment, the X-axis direction) of a pair of opposing wall portions (cover portions) 31, 32 in the rectangular parallelepiped or cubic shape.

[0037] Case 3 houses the electrolyte together with the electrode body 2 in its internal space. For this reason, Case 3 is made of a metal that is resistant to the electrolyte. In this embodiment, Case 3 is made of, for example, aluminum or an aluminum-based metal material such as an aluminum alloy.

[0038] Specifically, case 3 comprises a case body 30 having openings 30a and 30b and housing the electrode body 2. More specifically, case 3 comprises a cylindrical case body 30 having a first opening 30a and a second opening 30b at both ends in the X-axis direction, a first cover portion 31 that closes the first opening 30a, and a second cover portion 32 that closes the second opening 30b.

[0039] The case body 30 is in the shape of a rectangular tube. More specifically, the case body 30 is in the shape of a flat rectangular tube. This case body 30 has a pair of long wall portions 301 that face each other with a gap in the Y-axis direction, and a pair of short wall portions 302 that face each other with a gap in the Z-axis direction. In the case body 30 of the present embodiment, the first opening 30a and the second opening 30b have the same shape.

[0040] The long wall portion 301 is a portion that extends in the plane direction including the X-axis direction and the Z-axis direction in the case body 30. The long wall portion 301 of the present embodiment is in the shape of a rectangle that is long in the X-axis direction when viewed from the Y-axis direction.

[0041] The short wall portion 302 is a portion that extends in the plane direction including the X-axis direction and the Y-axis direction in the case body 30. This short wall portion 302 connects the edges of the long wall portion 301 in the Z-axis direction. The short wall portion 302 of the present embodiment is in the shape of a rectangle that is long in the X-axis direction when viewed from the Z-axis direction. The dimension of the short wall portion 302 of the present embodiment in the Y-axis direction (circumferential direction of the case body 30) is smaller than the dimension of the long wall portion 301 in the Z-axis direction (circumferential direction of the case body 30).

[0042] The first cover portion 31 extends in the plane direction including the Y-axis direction and the Z-axis direction and has the same shape as the first opening 30a when viewed from the X-axis direction. The first cover portion 31 of the present embodiment is a plate-like member in the shape of a rectangle that is long in the Z-axis direction when viewed from the X-axis direction.

[0043] The second cover portion 32 extends in the plane direction including the Y-axis direction and the Z-axis direction and has the same shape as the second opening 30b when viewed from the X-axis direction. The second cover portion 32 of the present embodiment is a plate-like member in the shape of a rectangle that is long in the Z-axis direction when viewed from the X-axis direction. Also, the second cover portion 32 of the present embodiment has the same shape as the first cover portion 31.

[0044] The terminal 4 includes a first terminal 41 that is electrically connected to the positive electrode 2a of the electrode body 2, and a second terminal 42 that is electrically connected to the negative electrode 2b of the electrode body 2.

[0045] The first terminal 41 is a portion that is electrically connected to an external terminal of another power storage element or an external device, etc. The first terminal 41 is disposed on the first cover portion 31 in a state of being electrically insulated from the first cover portion 31.

[0046] Specifically, the first terminal 41 has a first terminal body 411 extending along the first cover portion 31, and a first through portion 412 extending from the first terminal body 411 through the first cover portion 31 to the inside of the case 3 (see FIG. 1).

[0047] The first terminal 41 is formed of a conductive member. This first terminal 41 is formed of a highly weldable metal material such as an aluminum-based metal material such as aluminum or an aluminum alloy.

[0048] The second terminal 42 is a portion that is electrically connected to an external terminal of another power storage element or an external device. The second terminal 42 is disposed on the second cover portion 32 in a state of being electrically insulated from the second cover portion 32.

[0049] Specifically, the second terminal 42 has a second terminal body 421 extending along the second cover portion 32, and a second through portion 422 extending from the second terminal body 421 through the second cover portion 32 to the inside of the case 3 (see FIG. 1).

[0050] The second terminal 42 is formed of a conductive member. This second terminal 42 is formed of a highly weldable metal material such as a copper-based metal material such as copper or a copper alloy.

[0051] The rolling element 5 is spherical and is located between the electrode body 2 and the case body 30. In the power storage element 1 of the present embodiment, a plurality of rolling elements 5 are located between the electrode body 2 and the case body 30.

[0052] Specifically, the rolling element 5 is spherical. The particle diameter of the rolling element 5 is 1 μm to 200 μm. The particle diameter of the rolling element 5 is preferably 10 μm to 100 μm. The rolling element 5 is an inorganic particle. Specifically, the rolling element 5 is a glass bead, a ceramic bead made of alumina or zirconia, or the like. The rolling element 5 of the present embodiment is a glass bead. Here, the particle diameter means the average value of the particle diameters of the plurality of rolling elements 5. The particle diameter of each rolling element 5 is measured according to JIS Z8825. When the rolling element 5 is a perfect sphere, the particle diameter here refers to the diameter of the rolling element 5.

[0053] The rolling element 5 does not have to be a perfect sphere. Even if the rolling element 5 is not a perfect sphere, the particle size of the rolling element 5 is measured according to JIS Z 8825.

[0054] Next, the manufacturing method of the energy storage element 1 of this embodiment will be described with reference to Figures 5 and 6.

[0055] The prepared wound electrode body 2 is inserted into the case body 30. At this time, the rolling element 5 is positioned between the electrode body 2 and the case body 30.

[0056] Specifically, first, multiple rolling elements 5 are attached to the outer surface of the electrode body 2 (Step S1: see Figure 6). More specifically, multiple rolling elements 5 are attached to the outer surface of the electrode body 2 (the surface of the covering member 26) on both sides of the electrode body 2 in the Y-axis direction. In the manufacturing method of the energy storage element 1 of this embodiment, multiple rolling elements 5 are attached to the outer surface of the electrode body 2 by static electricity.

[0057] Next, with multiple rolling elements 5 attached to the outer surface of the electrode body 2, the electrode body 2 is inserted into the case body 30 through the first opening 30a (step S2). At this time, the electrode body 2 is inserted into the case body 30 in a state where the direction connecting the first opening 30a and the second opening 30b (X-axis direction) and the winding axis C of the electrode body 2 are parallel or approximately parallel.

[0058] Once the electrode body 2 has been inserted into the case body 30, the first terminal 41 is electrically connected to the positive electrode 2a of the electrode body 2, and the second terminal 42 is electrically connected to the negative electrode 2b of the electrode body 2 (step S3). At this time, the first terminal 41 is attached to the first cover portion 31, and the second terminal 42 is attached to the second cover portion 32.

[0059] Next, the first opening 30a of the case body 30 is closed with the first cover portion 31, and the second opening 30b of the case body 30 is closed with the second cover portion 32 (step S4). In this embodiment, the peripheral edge of the first cover portion 31 is welded to the peripheral edge of the opening 30a of the first opening in the case body 30, and the peripheral edge of the second cover portion 32 is welded to the peripheral edge of the opening 30b of the case body 30.

[0060] When the respective cover portions 31 and 32 close the respective openings 30a and 30b of the case body 30 to form the case 3, electrolyte is poured into the case 3 through the injection holes provided in the case 3 (step S5). Once a predetermined amount of electrolyte has been poured, the injection holes are closed and the case 3 is sealed (step S6), thereby completing the energy storage element 1.

[0061] The above method for manufacturing the energy storage element 1 includes inserting an electrode body 2 into a case body 30 having an opening 30a, and when inserting the electrode body 2 into the case body 30, rolling elements 5 are placed between the electrode body 2 and the case body 30. As a result, the rolling elements 5 roll between the electrode body 2 and the case body 30, making it easier to insert the electrode body 2 into the case body 30. In other words, the rolling of the rolling elements 5 between the electrode body 2 and the case body 30 reduces the resistance (friction) when inserting the electrode body 2 into the case body 30.

[0062] The energy storage element 1 of this embodiment comprises an electrode body 2, a case body 30 having an opening 30a and housing the electrode body 2, and rolling elements 5 disposed between the electrode body 2 and the case body 30. With this configuration, when the electrode body 2 is inserted into the case body 30, the rolling elements 5 roll between the electrode body 2 and the case body 30, making it easier to insert the electrode body 2 into the case body 30.

[0063] In the energy storage element 1 of this embodiment, the rolling element 5 is spherical. This makes it easier for the rolling element 5 to roll between the electrode body 2 and the case body 30 when the electrode body 2 is inserted into the case body 30, and as a result, it becomes easier to insert the electrode body 2 into the case body 30.

[0064] In the energy storage element 1 of this embodiment, the rolling elements 5 are inorganic particles. Because the rolling elements 5 are inorganic particles, the influence of the rolling elements 5 on the charging and discharging of the energy storage element 1 is suppressed.

[0065] Furthermore, the method for manufacturing an energy storage element and the energy storage element of the present invention are not limited to the embodiments described above, and various modifications can be made without departing from the spirit of the present invention. For example, the configuration of one embodiment can be added to the configuration of another embodiment, and a part of the configuration of one embodiment can be replaced with the configuration of another embodiment. In addition, a part of the configuration of one embodiment can be deleted.

[0066] In the manufacturing method of the energy storage element 1 of the above embodiment, the electrode body 2 is inserted into the case body 30 with the rolling elements 5 attached to the surface of the electrode body 2, but the method is not limited to this configuration. The rolling elements 5 may be attached to the inner surface of the case body 30, or they may be attached to the outer surface (surface) of the electrode body 2 and the inner surface of the case body 30. Alternatively, the rolling elements 5 may be attached to the outer surface of the electrode body 2 while (or simultaneously with) inserting the electrode body 2 into the case body 30.

[0067] In the manufacturing method of the energy storage element 1 in the above embodiment, the rolling elements 5 are attached to the outer surface of the electrode body 2 by static electricity, but the configuration is not limited to this. When inserting the electrode body 2 into the case body 30, the rolling elements 5 may be attached to the outer surface of the electrode body 2 by other methods such as adhesive, as long as they can roll between the electrode body 2 and the case body 30.

[0068] The case body 30 in the above embodiment is cylindrical with a first opening 30a and a second opening 30b, but is not limited to this configuration. The case body 30 may be box-shaped (bottomed cylindrical) with a single opening.

[0069] In the above embodiment, the case body 30 of the energy storage element 1 has a dimension in the X-axis direction that is larger than the dimension in the Z-axis direction, but the configuration is not limited to this. The dimension of the case body 30 in the X-axis direction may be smaller than the dimension in the Z-axis direction, or it may be the same as the dimension in the Z-axis direction.

[0070] Although the rolling element 5 in the above embodiment is spherical, it is not limited to this configuration. The rolling element 5 can be configured (shaped) to roll between the electrode body 2 and the case body 30 when the electrode body 2 is inserted into the case body 30. This reduces resistance (friction, etc.) when inserting the electrode body 2 into the case body 30. For example, the rolling element 5 may be elliptical, polygonal, or cylindrical. The rolling element 5 may also be spherical with small irregularities on its surface.

[0071] The rolling elements in the above embodiment are inorganic particles, but the configuration is not limited to this. The rolling elements 5 can be made of a material that does not react with the electrolyte, or a material that reacts with the electrolyte but does not affect the charging and discharging of the energy storage element 1.

[0072] The electrode stack 21 of the energy storage element 1 in the above embodiment is a wound type in which the electrodes are wound in a flat shape, but it is not limited to this configuration. The electrode stack 21 may also be a wound type in which the electrodes are wound in a cylindrical shape, or a stack type in which flat plates are stacked. Furthermore, the electrode stack 21 may also be a zigzag type in which the electrodes are folded in a zigzag pattern.

[0073] In the energy storage element 1 of the above embodiment, the electrode body 2 comprises one electrode stack 21, but is not limited to this configuration. The electrode body 2 may comprise two or more electrode stacks 21. In this case, a configuration in which multiple electrode stacks 21 are surrounded as a single unit by a covering member 26 is preferred in order to facilitate the insertion of multiple electrode stacks 21.

[0074] The features relating to rolling elements in claims 3 and 4 can also be applied to rolling elements in the manufacturing method of the energy storage element of claim 1. Furthermore, the measurement methods and modifications applicable to the rolling elements of the above embodiments can also be applied to rolling elements in the manufacturing method of the energy storage element.

[0075] 1...Energy storage element, 2...Electrode body, 2a...Positive electrode, 2b...Negative electrode, 21...Electrode stack, 211...Flat section, 212...Curved section, 26...Coating member, 3...Case, 30...Case body, 30a...First opening, 30b...Second opening, 301...Long wall section, 302...Short wall section, 31...First cover section, 32...Second cover section, 4...Terminal, 41...First terminal, 411...First terminal body, 412...First through section, 42...Second terminal, 421...Second terminal body, 422...Second through section, 5...Rolling element, C...Winding shaft

Claims

1. A method for manufacturing an energy storage element, comprising inserting an electrode body into a case body having an opening, wherein a rolling element is arranged between the electrode body and the case body during the insertion of the electrode body.

2. An energy storage element comprising: an electrode body; a case body having an opening and housing the electrode body; and rolling elements disposed between the electrode body and the case body.

3. The energy storage element according to claim 2, wherein the rolling element is spherical.

4. The energy storage element according to claim 2 or 3, wherein the rolling element is an inorganic particle.

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