Method for manufacturing power storage element, and power storage element

Abstract

A manufacturing method of a power storage element according to the present embodiment includes insertion of an electrode body into a cylindrical case body having a first opening and a second opening at both ends. In the insertion of the electrode body, a first end close to the first opening of the electrode body is pulled into the case body from the first opening.

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. 2024-225764 filed on December 20, 2024, and incorporates its content herein.

[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 deform when being 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 cylindrical case body having a first opening and a second opening at both ends. In the insertion of the electrode body, a first end portion of the electrode body close to the first opening is pulled into the case body from the first opening.

[0007] The storage element according to this embodiment includes an electrode body and a cylindrical case body that houses the electrode body. The electrode body includes an engagement portion for pulling the electrode 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] Figure 1 is a view of the energy storage element according to this embodiment, viewed from the Y-axis direction. Figure 2 is an exploded perspective view of the energy storage element. Figure 3 is a view of the electrode body of the energy storage element, viewed from the X-axis direction. Figure 4 is an exploded perspective view of the electrode body. Figure 5A is a view of the first fixed member of the electrode body, viewed from the Z-axis direction. Figure 5B is a view of the first fixed member, viewed from the Y-axis direction. Figure 5C is a cross-sectional view of the VC-VC position in Figure 5B. Figure 6A is a view of the second fixed member of the electrode body, viewed from the Z-axis direction. Figure 6B is a view of the second fixed member, viewed from the Y-axis direction. Figure 6C is a cross-sectional view of the VIC-VIC position in Figure 6B. Figure 7 is a flow diagram of the manufacturing method of the energy storage element. Figure 8 is a diagram illustrating the process of pulling the electrode body into the case body. Figure 9 is a diagram illustrating the process of pushing the electrode body into the case body. Figure 10 is a schematic diagram showing that the electrode body expands when it is pushed into the case body. Figure 11 shows the process of pulling the electrode body into the case body. Figure 12 is a schematic diagram showing that the electrode body becomes thinner when it is pulled into the case body. Figure 13 is a perspective view showing the electrode body 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 cylindrical case body having a first opening and a second opening at both ends, wherein, during the insertion of the electrode body, the first end of the electrode body closest to the first opening is pulled from the first opening into the case body.

[0011] According to a method for manufacturing an energy storage element according to one embodiment of the present invention, the electrode body is pulled into the case body from the first opening, thereby suppressing deformation of the electrode body when inserted into the case body, and thus facilitating insertion of the electrode body into the case body.

[0012] (2) In the method for manufacturing the energy storage element described in (1) above, when inserting the electrode body, the first end may be pulled into the case body by a jig inserted into the case body from the second opening toward the first opening.

[0013] According to the method for manufacturing the energy storage element described in (2) above, the use of a jig makes it easier to insert the electrode body into the case body.

[0014] (3) In the method for manufacturing an energy storage element as described in (1) or (2) above, the electrode body comprises a wound electrode, and when inserting the electrode body, the first end of the wound electrode may be pulled into the case body in the winding axis direction.

[0015] According to the method for manufacturing the energy storage element described in (3) above, the load on the electrode body due to friction when inserting the electrode body into the case body can be reduced.

[0016] (4) Another embodiment of the present invention provides an energy storage element comprising an electrode body and a cylindrical case body housing the electrode body, wherein the electrode body is provided with an engaging portion for pulling the electrode body.

[0017] According to another embodiment of the energy storage element of the present invention, the electrode body can be easily pulled into the case body by engaging a jig or the like with the engaging portion.

[0018] (5) In the energy storage element described in (4) above, the electrode body further comprises an electrode laminate in which electrodes are stacked, and a fixed member whose position is fixed with respect to the electrode laminate, and the fixed member may include the engagement portion.

[0019] According to the energy storage element described in (5) above, when the electrode body is inserted into the case body, the components other than the electrode stack (fixed components) are pulled, thereby reducing disturbance or damage to the electrodes in the electrode stack when inserted into the case body.

[0020] (6) In the energy storage element described in (5) above, the electrode stack includes a curved portion in which the electrodes are stacked in a curved state, and the fixed member may be located between the curved portion and the case body.

[0021] According to the energy storage element described in (6) above, the fixed member is placed in the gap between the curved portion and the case body within the case body, thereby suppressing the decrease in the energy density of the energy storage element caused by the fixed member being housed in the case body.

[0022] (7) In the energy storage element described in (5) or (6) above, the electrode body may further include a covering member that covers the electrode stack and the fixed member.

[0023] According to the energy storage element described in (7) above, the electrode stack and the fixed member can be integrated with a simple configuration, and as a result, the electrode body can be inserted into the case body more easily by pulling the fixed member.

[0024] Hereinafter, an embodiment of the present invention will be described with reference to Figures 1 to 13. First, the configuration of the energy storage element of this embodiment will be described, and then the manufacturing method of the energy storage element will be described. 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.

[0025] 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.

[0026] 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.

[0027] 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.

[0028] As shown in Figures 3 and 4, the electrode body 2 comprises an electrode stack 20 in which electrodes (positive electrode, negative electrode) are stacked, and a fixed member 23 whose position is fixed relative to the electrode stack 20. The electrode body 2 also includes a covering member 26 that covers the electrode stack 20 and the fixed member 23.

[0029] The electrode stack 20 includes a curved portion 202 in which electrodes are stacked in a curved state (see Figure 5). The electrode stack 20 of this embodiment includes a first electrode stack 21 and a second electrode stack 22. The positive electrode 21a of the first electrode stack 21 and the positive electrode 22a of the second electrode stack 22 constitute the positive electrode 2a of the electrode body 2. The negative electrode 21b of the first electrode stack 21 and the negative electrode 22b of the second electrode stack 22 constitute the negative electrode 2b of the electrode body 2.

[0030] The first electrode stack 21 comprises wound electrodes. In this embodiment, the first electrode stack 21 comprises flatly wound electrodes. In this first 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 first 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 C1 of the first electrode stack 21 extends is defined as the X-axis direction in the Cartesian coordinate system, the minor axis direction of the first electrode stack 21 is defined as the Y-axis direction in the Cartesian coordinate system, and the major axis direction of the first electrode stack 21 is defined as the Z-axis direction in the Cartesian coordinate system.

[0031] Specifically, the first electrode stack 21 has a first flat portion 211 that extends in the Z-axis direction when viewed from the X-axis direction, and a pair of first curved portions 212 that are positioned at both ends of the first flat portion 211 in the Z-axis direction when viewed from the X-axis direction.

[0032] The first flat portion 211 is a part of the first 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.

[0033] The first curved portion 212 is a region in which electrodes curved in a direction that is convex away from the first flat portion 211 when viewed from the X-axis direction are stacked in the Z-axis direction.

[0034] 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.

[0035] 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.

[0036] In the first electrode laminate 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 first electrode laminate 21 of this embodiment, the positive electrode, the negative electrode, and the separator are wound together in a laminated state.

[0037] 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 first 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.

[0038] The second electrode stack 22 has the same configuration as the first electrode stack 21. That is, the second electrode stack 22 in this embodiment includes wound electrodes. The second electrode stack 22 in this embodiment includes flat wound electrodes. 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.

[0039] Specifically, the second electrode laminate 22 has a second flat portion 221 extending in the Z-axis direction as viewed from the X-axis direction, and a pair of second curved portions 222 disposed at both ends of the second flat portion 221 in the Z-axis direction as viewed from the X-axis direction.

[0040] The second flat portion 221 is a portion where electrodes extending in the plane direction including the X-axis direction and the Z-axis direction in the second electrode laminate 22 are laminated in the Y-axis direction.

[0041] The second curved portion 222 is a portion where electrodes curved so as to be convex in a direction away from the second flat portion 221 as viewed from the X-axis direction are laminated in the Z-axis direction.

[0042] In this second electrode laminate 22, the positive electrode and the negative electrode are wound in a state of being insulated by a separator. That is, in the second electrode laminate 22 of the present embodiment, the positive electrode, the negative electrode, and the separator are wound in a laminated state.

[0043] The two electrode laminates (the first electrode laminate 21 and the second electrode laminate 22) configured as described above are accommodated in the case 3 in an adjacent posture such that the winding axes C1 and C2 are parallel or substantially parallel. More specifically, the first electrode laminate 21 and the second electrode laminate 22 are accommodated in the case 3 in an adjacent posture such that the winding axes C1 and C2 are parallel or substantially parallel and the first flat portion 211 and the second flat portion 221 are in contact with each other.

[0044] As shown in FIGS. 5A to 6C, the fixed member 23 includes an engaging portion 232 for pulling the electrode body 2 and is located between the curved portion 202 of the electrode laminate 20 and the case 3. The fixed member 23 of the present embodiment includes a first fixed member 24 and a second fixed member 25.

[0045] The first fixed member 24 extends in the X-axis direction within the case 3. The length of the first fixed member 24 in the X-axis direction is preferably 80% or more of the length of the case 3 in the X-axis direction. Thereby, the function of the first fixed member 24 as a guide when inserting the electrode body 2 into the case body 30 can be enhanced.

[0046] Specifically, the first fixed member 24 includes a first main body 241 extending in the X-axis direction and a first engaging portion 242 disposed at an end of the first main body 241 in the X-axis direction. The first fixed member 24 is located between the first curved portion 212, the second curved portion 222, and the covering member 26 at an end of the electrode body 2 in the Z-axis direction. The first fixed member 24 of the present embodiment has electrical insulation properties.

[0047] The first main body 241 has a shape that can be disposed in the gap between the first curved portion 212, the second curved portion 222, and the covering member 26 when viewed from the X-axis direction. The first main body 241 of the present embodiment is triangular when viewed from the X-axis direction. In other words, the first main body 241 has a triangular prism shape.

[0048] In the first main body 241 of the present embodiment, the first surface 241a facing the covering member 26 is a surface including the X-axis direction and the Y-axis direction. Also, the second surface 241b facing the first curved portion 212 is a surface that is inclined along the first curved portion 212 and inclined with respect to the first surface 241a when viewed from the X-axis direction. Further, the third surface 241c facing the second curved portion 222 is a surface that is inclined along the second curved portion 222 and inclined with respect to the first surface 241a when viewed from the X-axis direction. Note that the second surface 241b and the third surface 241c are flat surfaces, but they may be curved along the surface of the first curved portion 212 or the surface of the second curved portion 222.

[0049] The first engaging portion 242 is a portion that engages with a jig 6 (see FIG. 8) when the electrode body 2 is inserted into the case main body 30 during the manufacture of the power storage element 1. The first engaging portion 242 of the present embodiment has a shape that the jig 6 can catch on. For example, the first engaging portion 242 is a recess that recesses outward in the Z-axis direction (in other words, recesses toward the first surface 241a) at a position straddling the second surface 241b and the third surface 241c.

[0050] The second fixed member 25 has the same configuration as the first fixed member 24. That is, the second fixed member 25 extends in the X-axis direction within the case 3. The length of the second fixed member 25 in the X-axis direction is preferably 80% or more of the length of the case 3 in the X-axis direction.

[0051] Specifically, the second fixed member 25 comprises a second body 251 extending in the X-axis direction and a second engaging portion 252 positioned at the end of the second body 251 in the X-axis direction. This second fixed member 25 is located at the end of the electrode body 2 in the Z-axis direction, between the first curved portion 212, the second curved portion 222, and the covering member 26. The second fixed member 25 in this embodiment has electrical insulating properties.

[0052] The second body 251 has a shape that allows it to be positioned in the gap between the first curved portion 212, the second curved portion 222, and the covering member 26 when viewed from the X-axis direction. In this embodiment, the second body 251 is triangular when viewed from the X-axis direction. In other words, the second body 251 is triangular prism-shaped.

[0053] In the second body 251 of this embodiment, the fourth surface 251a facing the covering member 26 is a surface that includes the X-axis direction and the Y-axis direction. The fifth surface 251b facing the first curved portion 212 is a surface that, when viewed from the X-axis direction, follows the first curved portion 212 and is inclined with respect to the fourth surface 251a. The sixth surface 251c facing the second curved portion 222 is a surface that, when viewed from the X-axis direction, follows the second curved portion 222 and is inclined with respect to the fourth surface 251a. The fifth surface 251b and the sixth surface 251c are flat, but they may be curved to follow the surface of the first curved portion 212 or the surface of the second curved portion 222.

[0054] The second engaging portion 252 is the part that engages with the jig 6 (see Figure 8) when inserting the electrode body 2 into the case body 30 during the manufacturing of the energy storage element 1. In this embodiment, the second engaging portion 252 has a shape that the jig 6 catches on. For example, the second engaging portion 252 is a recess that is recessed outward in the Z-axis direction at a position spanning the fifth surface 251b and the sixth surface 251c (in other words, recessed toward the fourth surface 251a).

[0055] The covering member 26 electrically insulates the electrode laminate 20 from the case 3 by surrounding the electrode laminate 20 in the circumferential direction. This covering member 26 is an insulating and flexible sheet-like material (see Figure 4).

[0056] Specifically, the covering member 26 surrounds the first electrode stack 21, the second electrode stack 22, the first fixed member 24, and the second fixed member 25. More specifically, the covering member 26 integrally surrounds two electrode stacks (first electrode stack 21 and second electrode stack 22) aligned in the Y-axis direction, the first fixed member 24 which fits between the first curved portion 212 and the second curved portion 222 at one end of the electrode stacks 21 and 22 in the Z-axis direction, and the second fixed member 25 which fits between the first curved portion 212 and the second curved portion 222 at the other end of the electrode stacks 21 and 22 in the Z-axis direction.

[0057] The covering member 26 of this embodiment has a sheet-like body 261 and an adhesive layer 262 formed by an adhesive or the like on the inner surface of the body 261. The body 261 is insulating and is made of glass, ceramic, mica, or the like.

[0058] The main body 261 of the covering member 26 adheres to the first electrode laminate 21, the second electrode laminate 22, the first fixed member 24, and the second fixed member 25 via the adhesive layer 262, thereby fixing the first fixed member 24 and the second fixed member 25 to the first electrode laminate 21 and the second electrode laminate 22.

[0059] 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 axes C1 and C2 of the electrode stacks 21 and 22 are aligned with the opposing direction (in this embodiment, the X-axis direction) of a pair of opposing wall portions (cover portions) 31 and 32 in the rectangular parallelepiped or cubic shape.

[0060] 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.

[0061] 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.

[0062] The case body 30 is rectangular in shape. More specifically, the case body 30 is a flattened rectangular in shape. This case body 30 has a pair of long wall portions 301 that are spaced apart and facing each other in the Y-axis direction, and a pair of short wall portions 302 that are spaced apart and facing each other in the Z-axis direction. In the case body 30 of this embodiment, the first opening 30a and the second opening 30b have the same shape.

[0063] The elongated wall portion 301 is a part of the case body 30 that extends in a planar direction including the X-axis and Z-axis directions. In this embodiment, the elongated wall portion 301 is a rectangular shape that is elongated in the X-axis direction when viewed from the Y-axis direction.

[0064] The short wall portion 302 is a part of the case body 30 that extends in a planar direction including the X-axis and Y-axis directions. This short wall portion 302 connects to the edge of the long wall portion 301 in the Z-axis direction. In this embodiment, the short wall portion 302 is a rectangular shape that is elongated in the X-axis direction when viewed from the Z-axis direction. In this embodiment, the dimension of the short wall portion 302 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).

[0065] The first cover portion 31 extends in a planar direction including the Y-axis and Z-axis directions, and has the same shape as the first opening 30a when viewed from the X-axis direction. In this embodiment, the first cover portion 31 is a rectangular plate-like member that is elongated in the Z-axis direction when viewed from the X-axis direction.

[0066] The second cover portion 32 extends in a planar direction including the Y-axis and Z-axis directions, and has the same shape as the second opening 30b when viewed from the X-axis direction. In this embodiment, the second cover portion 32 is a rectangular plate-like member that is elongated in the Z-axis direction when viewed from the X-axis direction. Furthermore, the second cover portion 32 in this embodiment has the same shape as the first cover portion 31.

[0067] 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.

[0068] The first terminal 41 is a part that is electrically connected to the external terminals of other energy storage elements or to external equipment, etc. The first terminal 41 is arranged on the first cover portion 31 in a state where it is electrically insulated from the first cover portion 31.

[0069] Specifically, the first terminal 41 has a first terminal body 411 that extends along the first cover portion 31, and a first through portion 412 that extends from the first terminal body 411 through the first cover portion 31 into the case 3 (see Figure 1).

[0070] The first terminal 41 is formed from a conductive material. This first terminal 41 is formed from a highly weldable metal material, such as aluminum or an aluminum alloy.

[0071] The second terminal 42 is a part that is electrically connected to the external terminals of other energy storage elements or to external devices, etc. The second terminal 42 is arranged on the second cover portion 32 in a state of being electrically insulated from the second cover portion 32.

[0072] Specifically, the second terminal 42 has a second terminal body 421 that extends along the second cover portion 32, and a second through portion 422 that extends from the second terminal body 421 through the second cover portion 32 into the case 3 (see Figure 1).

[0073] The second terminal 42 is formed from a conductive material. This second terminal 42 is formed from a highly weldable metal material, such as copper or a copper alloy.

[0074] Next, the manufacturing method of the energy storage element 1 of this embodiment will be described with reference to Figures 7 and 8.

[0075] First, prepare the electrode body (Step S1: See Figures 3 to 5).

[0076] Specifically, the first electrode stack 21 and the second electrode stack 22 are arranged such that the winding axes C1 and C2 are parallel and the first flat portion 211 and the second flat portion 221 are adjacent to each other.

[0077] Next, at both ends of the first electrode stack 21 and the second electrode stack 22 in the Z-axis direction, the first fixed member 24 and the second fixed member 25 are placed between the first curved portion 212 and the second curved portion 222.

[0078] More specifically, the first fixed member 24 is positioned such that its second surface 241b contacts the first curved portion 212 and its third surface 241c contacts the second curved portion 222. At this time, the first fixed member 24 is positioned such that its first engaging portion 242 protrudes in the X-axis direction from the first electrode stack 21 and the second electrode stack 22.

[0079] Furthermore, the second fixed member 25 is positioned such that its fifth surface 251b contacts the first curved portion 212 and its sixth surface 251c contacts the second curved portion 222. At this time, the second fixed member 25 is positioned such that its second engaging portion 252 protrudes in the X-axis direction from the first electrode stack 21 and the second electrode stack 22.

[0080] In this state, the electrode body 2 is formed by wrapping the covering member 26 around the first electrode stack 21, the second electrode stack 22, the first fixed member 24, and the second fixed member 25 as a single unit in the circumferential direction.

[0081] Next, the electrode body 2 is inserted into the case body 30 (step S2). During the insertion of the electrode body 2 into the case body 30, the end of the electrode body 2 closest to the first opening 30a of the case body 30 (in the example shown in Figure 8, the end where the negative electrode 2b is formed: the first end) 2A is pulled into the case body 30 from the first opening 30a.

[0082] In the manufacturing method of the energy storage element 1 of this embodiment, when inserting the electrode body 2 into the case body 30, as shown in Figure 8, the first end 2A of the electrode body 2 is pulled into the case body 30 by a jig 6 inserted into the case body 30 from the second opening 30b toward the first opening 30a. The details are as follows.

[0083] The jig 6 comprises a first extension portion 61 extending in the X-axis direction, a second extension portion 62 extending in the X-axis direction, a third engaging portion 63 positioned at the tip of the first extension portion 61, and a fourth engaging portion 64 positioned at the tip of the second extension portion 62.

[0084] The first extension portion 61 and the second extension portion 62 each extend in the X-axis direction, and the first extension portion 61 and the second extension portion 62 are arranged parallel to each other with a gap in the Z-axis direction. These first extension portion 61 and the second extension portion 62 are longer than the case body 30 in the X-axis direction. The third engagement portion 63 is removablely engageable with the first engagement portion 242 of the electrode body 2. The fourth engagement portion 64 is removablely engageable with the second engagement portion 252 of the electrode body 2. In this embodiment, the third engagement portion 63 and the fourth engagement portion 64 each have a hook shape that is curved outward in the Z-axis direction.

[0085] Then, when inserting the electrode body 2 into the case body 30, the jig 6 is inserted into the case body 30 from the second opening 30b until the third engaging portion 63 and the fourth engaging portion 64 protrude from the first opening 30a, thereby engaging the third engaging portion 63 with the first engaging portion 242 of the electrode body 2 and engaging the fourth engaging portion 64 with the second engaging portion 252 of the electrode body.

[0086] Next, by moving the jig 6 in the direction from the first opening 30a toward the second opening 30b, the electrode body 2 is pulled by the jig 6 and drawn into the case body 30 from the first opening 30a.

[0087] When the entire electrode body 2 is pulled into the case body (i.e., inserted), the engagement between the third engaging portion 63 of the jig 6 and the first engaging portion 242 of the electrode body 2 is released, and the engagement between the fourth engaging portion 64 of the jig 6 and the second engaging portion 252 of the electrode body 2 is released.

[0088] 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.

[0089] 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 opening peripheral edge of the first opening 30a, and the peripheral edge of the second cover portion 32 is welded to the opening peripheral edge of the second opening 30b.

[0090] 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.

[0091] The above method for manufacturing the energy storage element 1 involves inserting an electrode body 2 into a cylindrical case body 30 having a first opening 30a and a second opening 30b at both ends. During insertion of the electrode body 2, the first end 2A of the electrode body 2, which is close to the first opening 30a, is pulled from the first opening 30a into the case body 30.

[0092] According to the manufacturing method of an energy storage element according to one embodiment of the present invention, the electrode body 2 is pulled into the case body 30 from the first opening 30a, thereby suppressing deformation of the electrode body 2 when inserted into the case body 30, and thus making it easier to insert the electrode body 2 into the case body 30. Details are as follows.

[0093] As shown in Figure 9, when the electrode body 2 is pushed into the cylindrical case body 30, more specifically, when the end (second end) 2B of the electrode body 2 furthest from the first opening 30a is pushed, and the first end 2A is pushed into the case body 30 through the first opening 30a, friction between the inner surface of the case body 30 and the outer surface (surface) of the electrode body 2 applies a force (see arrow A2 in Figure 10) to the electrode body 2 that is applied to the electrode body 2 in the opposite direction to the force applied to the electrode body 2 to push it into the case body 30 (see arrow A1 in Figure 10). Due to these clamping forces A1 and A2 in the X-axis direction, the electrode body 2 expands, causing the central part to bulge, which makes it difficult to push the electrode body 2 into the case body 30. Note that in Figure 10, the electrode body 2 is depicted schematically and with the bulge exaggerated to show the bulge.

[0094] On the other hand, in the manufacturing method of the energy storage element 1 of this embodiment, as shown in Figure 11, the electrode body 2 is pulled into the cylindrical case body 30. More specifically, by pulling the end (first end) 2A of the electrode body 2 that is close to the first opening 30a, the first end 2A is pulled from the first opening 30a into the case body 30. As a result, friction between the inner surface of the case body 30 and the outer surface (surface) of the electrode body 2 applies a force (see arrow B2 in Figure 12) to the electrode body 2 that is applied to pull the electrode body 2 into the case body 30 (see arrow B1 in Figure 12). These forces B1 and B2, which are moving away from each other in the X-axis direction, cause the electrode body 2 to become thinner, making it easier to pull the electrode body 2 into the case body 30. Note that in Figure 13, the electrode body 2 is depicted schematically and with an exaggerated thinning to show the thinning.

[0095] In the manufacturing method of the energy storage element 1 of this embodiment, when inserting the electrode body 2 into the case body 30, the first end portion 2A is pulled into the case body 30 by a jig 6 inserted into the case body 30 from the second opening 30b toward the first opening 30a. By using the jig 6 when pulling the electrode body 2 into the case body 30 in this way, insertion of the electrode body 2 into the case body 30 becomes easier.

[0096] In the manufacturing method of the energy storage element 1 of this embodiment, the electrode body 2 is equipped with wound electrodes, and when the electrode body 2 is inserted into the case body 30, the first end portion 2A is pulled into the case body 30 in the X-axis direction (the direction of the winding axes C1 and C2 of the wound electrodes). This reduces the load on the electrode body due to friction when inserting the electrode body into the case body. Furthermore, by reducing the load on the electrode body, it is possible to reduce the deterioration of the quality of the energy storage element due to the electrodes becoming disordered.

[0097] The energy storage element 1 of this embodiment comprises an electrode body 2 and a cylindrical case body 30 that houses the electrode body 2. The electrode body 2 is provided with an engaging portion 232 for pulling the electrode body 2. Therefore, during the manufacturing of the energy storage element 1, the electrode body 2 can be easily pulled into the case body 30 by engaging a jig 6 or the like with the engaging portion 232.

[0098] In the energy storage element 1 of this embodiment, the electrode body 2 further comprises an electrode stack 20 in which electrodes are stacked, and a fixed member 23 whose position is fixed relative to the electrode stack 20, and the fixed member 23 is provided with an engaging portion 232. Therefore, when inserting the electrode body 2 into the case body 30 during the manufacturing of the energy storage element 1, the members other than the electrode stack 20 (the fixed member 23) are pulled, thereby reducing deformation of the electrode stack 20 (disorder or damage to the electrodes, etc.) when inserted into the case body 30.

[0099] In the energy storage element 1 of this embodiment, the electrode stack 20 (first electrode stack 21 or second electrode stack 22) includes curved portions 212 and 222 in which electrodes are stacked in a curved state, and the fixed member 23 (first fixed member 24 or second fixed member 25) is located between the curved portions 212 and 222 and the case body 30. In this way, by arranging the fixed members 24 and 25 in the gap between the curved portions 212 and 222 and the case body 30 within the case body 30, the decrease in energy density of the energy storage element 1 caused by the fixed members 24 and 25 being housed in the case body 30 is suppressed.

[0100] In the energy storage element 1 of this embodiment, the electrode body 2 further comprises a covering member 26 that covers the electrode stack 20 and the fixed member 23. In this way, the electrode stack 20 and the fixed member 23 can be integrated with a simple configuration, thereby further reducing the disturbance or damage of the electrodes in the electrode stack 21 and 22 when inserting the fixed member 23 into the case body 30 by pulling it.

[0101] It should be noted that the method for manufacturing the 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. Furthermore, a part of the configuration of one embodiment can be deleted.

[0102] In the manufacturing method of the energy storage element 1 of the above embodiment, when the electrode body 2 is inserted into the case body 30, the end (first end) 2A of the electrode body 2 on which the negative electrode 2b is formed is pulled into the case body 30 from the first opening 30a, but the method is not limited to this configuration.

[0103] The electrode body 2 may be pulled into the case body 30 through the first opening 30a at the end (second end) 2B where the positive electrode 2a is formed. Alternatively, the electrode body 2 may be pulled into the case body 30 through the first opening 30a at the end where the curved portions 212 and 222 of each electrode stack 21 and 22 are formed. Furthermore, the electrode body 2 may be pulled in through the second opening 30b of the case body 30.

[0104] In the manufacturing method of the energy storage element 1 of the above embodiment, the electrode body 2 is pulled into the case body 30 by the jig 6, but the configuration is not limited to this. For example, a part of the electrode body 2 may extend in the X-axis direction from the first end 2A, and the electrode body 2 may be pulled into the case body 30 by pulling this part.

[0105] In the manufacturing method of the energy storage element 1 of the above embodiment, the electrode body 2 is provided with a portion (first engaging portion 242 and second engaging portion 252) for pulling the electrode body 2, but the method is not limited to this configuration. The electrode body 2 does not need to have a portion provided for pulling the electrode body 2. In this case, when pulling the electrode body 2 into the case body 30, it is sufficient to pull a part of the electrode body 2.

[0106] In the manufacturing method of the energy storage element 1 of the above embodiment, the electrode body 2 includes a first fixed member 24 having a first engaging portion 242 and a second fixed member 25 having a second engaging portion 252, but the configuration is not limited to this. As long as the first engaging portion 242 and the second engaging portion 252 are formed on the electrode stack 21, 22 or the covering member 26, the electrode body 2 does not need to include the first fixed member 24 and the second fixed member 25.

[0107] The specific shapes of the first engaging portion 242 and the second engaging portion 252 are not limited. In the above embodiment, the first engaging portion 242 and the second engaging portion 252 are recesses that are recessed outward in the Z-axis direction, but they can be annular, through holes, or any other shape that can be pulled by a jig 6 or the like. The first engaging portion 242 and the second engaging portion 252 may have different shapes.

[0108] The electrode body 2 in the above embodiment is equipped with fixed members 24 and 25, but is not limited to this configuration. For example, the electrode body 2 may have no engaging portions 242 and 252 and no fixed members 24 and 25. In this case, in the manufacturing method of the energy storage element 1, the first end portion 2A of the electrode body 2 may be held by a jig 6 or the like and pulled into the case body 30.

[0109] In the manufacturing method of the energy storage element 1 of the above embodiment, the first fixed member 24 and the second fixed member 25 are located between the first curved portion 212, the second curved portion 222, and the short wall portion 302, but the configuration is not limited to this. The first fixed member 24 and the second fixed member 25 may be located between the first flat portion 211 and the long wall portion 301, between the second flat portion 221 and the long wall portion 301, or between the electrode body 2 and the cover portions 31 and 32 in the X-axis direction. When the first fixed member 24 and the second fixed member 25 are arranged in these positions, it is preferable that the first fixed member 24 and the second fixed member 25 have a shape that requires little space for arrangement, such as a strip shape (narrow plate shape) or a plate shape.

[0110] In the manufacturing method of the energy storage element 1 of the above embodiment, nothing is placed between the electrode body 2 and the case body 30 when inserting the electrode body 2 into the case body 30, but the method is not limited to this configuration. When inserting the electrode body 2 into the case body 30, rolling elements 5 may be placed between the electrode body 2 and the case body 30. This allows the rolling elements 5 to 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. Further details are as follows.

[0111] The rolling elements 5 are spherical and are located between the electrode body 2 and the case body 30. In the example of inserting the electrode body 2 into the case body 30 shown in Figure 13, multiple rolling elements 5 are located between the electrode body 2 and the case body 30.

[0112] Specifically, the rolling element 5 is spherical. The particle diameter of the rolling element 5 is 1 μm to 200 μm. Preferably, the particle diameter of the rolling element 5 is 10 μm to 100 μm. The rolling element 5 is an inorganic particle. Specifically, the rolling element 5 is a glass bead, alumina, or a ceramic bead made of zirconia, etc. In this embodiment, the rolling element 5 is a glass bead. The particle diameter referred to here is the average value of the particle diameters of multiple rolling elements 5. The particle diameter of each rolling element 5 is measured according to JIS Z 8825. If the rolling element 5 is a perfect sphere, the particle diameter referred to here is the diameter of the rolling element 5.

[0113] 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.

[0114] Furthermore, in the manufacturing method of the energy storage element 1, before inserting the electrode body 2 into the case body 30, a plurality of rolling elements 5 are attached to the outer circumferential surface of the electrode body 2. Specifically, the plurality of rolling elements 5 are attached to the outer circumferential surface of the electrode body 2 (the surface of the covering member 26) on both sides in the Y-axis direction of the electrode body 2. In the example shown in Figure 13, the plurality of rolling elements 5 are attached to the outer circumferential surface of the electrode body 2 by static electricity. Once the plurality of rolling elements 5 are attached to the outer circumferential surface of the electrode body 2 in this way, the electrode body 2 is then pulled into the case body 30 through the first opening 30a. As a result, compared to a configuration in which rolling elements are not attached to the outer circumferential surface of the electrode body, the rolling elements 5 roll along with the movement of the electrode body 2, thus reducing resistance (friction) when inserting the electrode body 2 into the case body 30.

[0115] In the example shown in Figure 14, the rolling element 5 is spherical, but the configuration is not limited to this. The rolling element 5 can roll between the electrode body 2 and the case body 30 when the electrode body 2 is inserted into the case body 30, thereby reducing resistance (friction, etc.) when the electrode body 2 is inserted into the case body 30.

[0116] In the manufacturing method of the energy storage element 1 described above, 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 electrode body 2 may be inserted into the case body 30 while the rolling elements 5 are attached to the outer surface of the electrode body 2.

[0117] Furthermore, in the manufacturing method of the energy storage element 1 described above, the rolling elements 5 are attached to the outer surface of the electrode body 2 by static electricity, but the method is not limited to this configuration. The rolling elements 5 may also be attached to the outer surface of the electrode body 2 by other methods such as adhesive.

[0118] In the above embodiment, the first fixed member 24 and the second fixed member 25 are fixed to the first electrode stack 21 and the second electrode stack 22 via a covering member 26, but the configuration is not limited to this. The first fixed member 24 and the second fixed member 25 may be directly fixed to the first electrode stack 21 and the second electrode stack 22.

[0119] In the energy storage element 1 of the above embodiment, the electrode body 2 is provided with two fixed members (first fixed member 24 and second fixed member 25), but the configuration is not limited to this. The electrode body 2 may be provided with one fixed member, or with three or more fixed members.

[0120] In the energy storage element 1 of the above embodiment, the electrode body 2 is provided with a covering member 26, but the configuration is not limited to this. The electrode body 2 does not need to be provided with a covering member 26.

[0121] 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.

[0122] Here, the larger the X-axis dimension of the case body 30 is relative to the Z-axis dimension, the more difficult it becomes to insert the electrode body 2 into the case body 30. For this reason, the larger the X-axis dimension of the case body 30 is relative to the Z-axis dimension, the more pronounced the effect of making it easier to insert the electrode body 2 into the case body 30 becomes when adopting a configuration in which the first end 2A of the electrode body 2 is pulled into the case body 30 from the first opening 30a, as in the manufacturing method of the energy storage element 1 in the above embodiment.

[0123] The electrode stacks 21 and 22 of the energy storage element 1 in the above embodiment are of the wound type, in which the electrodes are wound in a flat shape, but the configuration is not limited to this. The electrode stacks 21 and 22 may also be of the wound type, in which the electrodes are wound in a cylindrical shape, or they may be of the stack type, in which flat plates of electrodes are stacked. Furthermore, the electrode stacks 21 and 22 may also be of the zigzag type, in which the electrodes are folded in a zigzag pattern.

[0124] In the energy storage element 1 of the above embodiment, the electrode body 2 comprises two electrode stacks (first electrode stack 21 and second electrode stack 22), but the configuration is not limited to this. The electrode body 2 may comprise one electrode stack, or it may comprise three or more electrode stacks.

[0125] The specific configuration of the engaging portion of the electrode body 2 (first engaging portion 242 and second engaging portion 252 in the above embodiment) and the engaging portion of the jig 6 (third engaging portion 63 and fourth engaging portion 64 in the above embodiment) is not limited. One of the engaging portions of the electrode body 2 and the jig 6 may be hook-shaped, and the other engaging portion may be annular or hook-shaped, etc.

[0126] Furthermore, in the above embodiment, the engaging portions 242 and 252 of the electrode body 2 are groove-shaped recesses extending in the Y-axis direction, and the engaging portions 63 and 64 of the jig 6 in the above embodiment are hook-shaped to catch on the engaging portions (groove-shaped recesses) 242 and 252 of the electrode body. However, for example, one of the engaging portions of the electrode body 2 and the jig 6 may be composed of a columnar recess extending in the Z-axis direction, and the other engaging portion of the electrode body 2 and the jig 6 may be composed of a columnar protrusion that catches on the columnar recess. The cross-sectional shape of the columnar protrusion and the cross-sectional shape of the columnar recess do not have to be the same. That is, it is sufficient that the columnar protrusion catches on the columnar recess when the electrode body 2 is pulled by the jig 6.

[0127] Furthermore, one of the engaging portions 242, 252 of the electrode body 2 and the engaging portions 63, 64 of the jig 6 may be a columnar protrusion extending in the Z-axis direction, and the other engaging portion 242, 252 of the electrode body 2 and the engaging portions 63, 64 of the jig 6 may have a hole into which the columnar protrusion catches. The cross-sectional shape of the columnar protrusion and the cross-sectional shape of the hole do not have to be the same. That is, it is sufficient that the columnar protrusion catches in the hole when the electrode body 2 is pulled by the jig 6.

[0128] Alternatively, when the electrode body 2 is pulled by the jig 6, the engaging portions 63 and 64 of the jig 6 may be configured to hold the engaging portions 242 and 252 of the electrode body 2 by clamping or other means.

[0129] As described above, the engagement portion of the electrode body 2 and the engagement portion of the jig 6 should be such that the jig 6 can pull the entire electrode body 2 into the case body 30 by pulling the first end portion 2A of the electrode body 2, and the engagement can be released (disengaged) after the entire electrode body 2 has been pulled into the case body 30.

[0130] In the energy storage element 1 of the above embodiment, the fixed member 23 remains inside the case 3, but the configuration is not limited to this.

[0131] For example, during the manufacturing of the energy storage element 1, the fixed member 23 may be removed from the electrode body 2 after the electrode body 2 has been drawn into the case body 30. In this case, the fixed member 23 does not remain inside the case 3 in the completed energy storage element 1.

[0132] Furthermore, the fixed members 24 and 25 may be configured so that the engaging portions 242 and 252 can be removed from the main bodies 241 and 251. That is, during the manufacturing of the energy storage element 1, after the electrode body 2 is pulled into the case body 30, the engaging portions 242 and 252 may be removed from the fixed members 24 and 25. In this case, in the completed energy storage element 1, the main bodies 241 and 251 of the fixed members 24 and 25 remain inside the case 3.

[0133] In the above embodiment, the first body 241 of the first fixed member 24 and the second body 251 of the second fixed member 25 are triangular prisms, but the configuration is not limited to this. For example, the first body 241 of the first fixed member 24 and the second body 251 of the second fixed member 25 may be rectangular prisms, cylinders, or elliptical prisms. The first body 241 of the first fixed member 24 and the second body 251 of the second fixed member 25 may be long plates in the X-axis direction, such as rectangular plates, which are placed between the electrode body 2 and the short wall portion 302 of the case body 30. In other words, the first body 241 of the first fixed member 24 and the second body 251 of the second fixed member 25 only need to have a shape that extends in the X-axis direction.

[0134] The cross-sections of the first body 241 and the second body 251 may be circular or elliptical, triangular with rounded corners, square, or square with rounded corners. In other words, the cross-sections of the first body 241 and the second body 251 may be any shape that can be placed in the gap between the first curved portion 212, the second curved portion 222, and the covering member 26. Furthermore, if the electrode body 2 does not have a covering member 26, the cross-sections of the first body 241 and the second body 251 may be any shape that can be placed in the gap between the first curved portion 212, the second curved portion 222, and the short wall portion 302 of the case 3. Also, the cross-sections of the first body 241 and the second body 251 may be different shapes.

[0135] 1...Energy storage element, 2...Electrode body, 2a...Positive electrode of electrode body, 2b...Negative electrode of electrode body, 20...Electrode stack, 202...Bent portion, 21...First electrode stack, 21a...Positive electrode of first electrode stack, 21b...Negative electrode of first electrode stack, 211...First flat portion, 212...First curved portion, 22...Second electrode stack, 22a...Positive electrode of second electrode stack, 22b...Negative electrode of second electrode stack, 221...Second flat portion, 222...Second curved portion, 23...Fixed member, 232...Engaging portion, 24...First fixed member, 241...First main body, 241a...First surface, 241b...Second surface, 241c...Third surface 242...First engaging part, 25...Second fixed member, 251...Second main body, 251a...Fourth surface, 251b...Fifth surface, 251c...Sixth surface, 252...Second engaging part, 26...Covering member, 261...Main body, 262...Adhesive layer, 3...Case, 30...Case body, 30a...First opening, 30b...Second opening, 301...Long wall part, 302...Short wall part, 31...First cover part, 32...Second cover part, 4...Terminal, 41...First terminal, 411...First terminal body, 412...First through part, 42...Second terminal, 421...Second terminal body, 422...Second through part, 5...Rolling element, C1, C2...Winding shaft

Claims

1. A method for manufacturing an energy storage element, comprising inserting an electrode body into a cylindrical case body having a first opening and a second opening at both ends, wherein, during insertion of the electrode body, the first end of the electrode body closest to the first opening is pulled from the first opening into the case body.

2. The method for manufacturing an energy storage element according to claim 1, wherein, in the insertion of the electrode body, the first end is pulled into the case body by a jig inserted into the case body from the second opening toward the first opening.

3. The method for manufacturing an energy storage element according to claim 1 or 2, wherein the electrode body comprises a wound electrode, and during insertion of the electrode body, the first end of the wound electrode is pulled into the case body in the winding axis direction.

4. An energy storage element comprising an electrode body and a cylindrical case body for housing the electrode body, wherein the electrode body is provided with an engaging portion for pulling the electrode body.

5. The electrode body further comprises an electrode laminate in which electrodes are stacked, and a fixed member whose position is fixed with respect to the electrode laminate, wherein the fixed member comprises the engaging portion, as described in claim 4.

6. The energy storage element according to claim 5, wherein the electrode stack comprises a curved portion in which the electrodes are stacked in a curved state, and the fixed member is located between the curved portion and the case body.

7. The energy storage element according to claim 5 or 6, wherein the electrode body further comprises the electrode laminate and a covering member that covers the fixed member.

Images