Energy storage cell

Abstract

To provide a power storage cell capable of maintaining the wound state of a wound electrode body while suppressing the wound electrode body from being subjected to localized pressure in the wound electrode body.SOLUTION: A power storage cell 100 has a wound electrode body 1 that includes: a positive electrode plate 10 (first electrode); a negative electrode plate 20 (second electrode); and a separator 30; and a fixing member 8 for fixing the wound electrode body 1 so as to maintain the wound electrode body 1 is wound in a spiral manner. The wound electrode body 1 includes: an end face 1a (first end face) at one side in the Z direction (axial direction) where the winding axis α extends; and the other end face 1b (second end face) in the Z direction. The fixing member 8 is provided at least on the end face 1a.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present disclosure relates to a storage cell.

Background Art

[0002] International Publication No. 2018 / 105398 (Patent Document 1) discloses a secondary battery including an electrode body in which a positive electrode and a negative electrode are wound in a spiral shape via a separator. A tape for fixing the end portion after winding is attached to the outer peripheral surface of the electrode body. The electrode body is housed in a case.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In Patent Document 1 above, in order to restrict the movement of the electrode body, the space between the outer peripheral surface of the electrode body and the inner peripheral surface of the case is small. Therefore, when the electrode body expands or the like, the tape and the case interfere with each other, and local pressure occurs at the portion where the tape is attached.

[0005] The present disclosure has been made to solve the above problems, and an object thereof is to provide a storage cell capable of maintaining the wound state of a wound electrode body while suppressing the occurrence of local pressure in the wound electrode body.

Means for Solving the Problems

[0006] A storage cell according to one aspect of the present disclosure comprises a wound electrode body including a first electrode, a second electrode, and a separator disposed between the first electrode and the second electrode, and a fixing member for fixing the wound electrode body so as to maintain the wound state of the wound electrode body. The wound electrode body is wound such that the first electrode, the second electrode, and the separator surround a winding axis. The wound electrode body includes a first end face on one axial side on which the winding axis extends, and a second end face on the other axial side. The fixing member is provided on at least the first end face.

[0007] In a power storage cell according to one aspect of this disclosure, as described above, a fixing member is provided on the first end face. This allows the winding state of the winding electrode body to be maintained by the fixing member on the first end face without having to attach fixing tape to the side surface of the winding electrode body. As a result, the winding state of the winding electrode body can be maintained while suppressing the generation of local pressure on the winding electrode body caused by the attachment of tape.

[0008] In the energy storage cell relating to the first aspect described above, preferably, a fixing member is also provided on the second end face. With this configuration, the winding state of the wound electrode body can be maintained by utilizing the fixing member on the second end face in addition to the fixing member on the first end face. This makes it possible to maintain the winding state of the wound electrode body more firmly.

[0009] In the energy storage cell relating to the first aspect described above, preferably, the wound electrode body includes a circumferential surface located between the first end face and the second end face. The fixing member is provided at a position closer to the circumferential surface than to the winding axis. With this configuration, the fixing member is positioned on the radially outer portion of the wound electrode body, so that the winding of the wound electrode body does not unravel from the radially outer side.

[0010] In this case, preferably, the fixing member is provided between the winding axis and the circumferential surface, extending along the radial direction of the wound electrode body. With this configuration, the radial length of the fixing member can be made relatively large, so the wound state of the wound electrode body can be maintained more firmly. In addition, compared to the case where the fixing member does not extend radially, the radially inner portion of the wound electrode body can also be easily fixed by the fixing member. This makes it possible to suppress the unraveling of the winding of the wound electrode body from the radially inner side during handling of the wound electrode body, etc.

[0011] The energy storage cell, in which the above-mentioned fixing member extends radially, comprises a cylindrical case that houses the wound electrode body. The radial length of the fixing member is less than or equal to the radius of the case. With this configuration, even if two fixing members are placed side by side radially, interference between the fixing members and the case can be suppressed.

[0012] In the energy storage cell relating to the first aspect described above, preferably, the wound electrode body includes the end portion of the winding. The fixing member is provided at the end portion. With this configuration, it is possible to suppress the unraveling of the winding of the wound electrode body from the end portion.

[0013] In the energy storage cell relating to the first aspect described above, preferably, the wound electrode body includes an exposed portion that is not fitted with a fixing member when viewed along the axial direction. With this configuration, when the electrolyte is injected from the axial direction of the wound electrode body, it is possible to suppress obstruction of the electrolyte flow by the fixing member compared to when the fixing member covers the entire (surface) of the wound electrode body.

[0014] In the energy storage cell relating to the first aspect described above, preferably, the fixing member includes a base material and an adhesive layer provided on the base material. The base material is formed of an elastically deformable resin. With this configuration, when the first electrode expands in the axial direction, the base material can be elastically deformed. This makes it possible to suppress cracking of the base material.

[0015] In the energy storage cell relating to the first aspect described above, preferably, the first electrode includes a first current collector and a first electrode material layer coated on a part of the first current collector and facing the separator in the radial direction of the wound electrode body. The first current collector has a first coated portion coated with the first electrode material layer and a first uncoated portion located on a first end face on one side in the axial direction of the first coated portion and not coated with the first electrode material layer. The fixing member is provided in the first uncoated portion. With this configuration, by providing the fixing member in the first uncoated portion where the first electrode material layer is not coated, it is possible to suppress the load applied to the first electrode material layer by the fixing member when the wound electrode body expands.

[0016] In the energy storage cell relating to the first aspect described above, preferably, the second electrode includes a second current collector and a second electrode material layer coated on a part of the second current collector and facing the separator in the radial direction. The second current collector has a second coated portion coated with the second electrode material layer and a second uncoated portion located on the second end face on the other axial side of the second coated portion and not coated with the second electrode material layer. The fixing member is provided in the second uncoated portion. With this configuration, by providing the fixing member in the second uncoated portion where the second electrode material layer is not coated, it is possible to suppress the load applied to the second electrode material layer by the fixing member when the wound electrode body expands.

[0017] According to this disclosure, it is possible to maintain the winding state of the wound electrode body while suppressing the generation of localized pressure in the wound electrode body. [Brief explanation of the drawing]

[0018] [Figure 1] This is a cross-sectional view showing the configuration of a storage cell according to one embodiment. [Figure 2] This is a schematic perspective view showing the configuration of a wound electrode body according to one embodiment. [Figure 3] This is a magnified view of the positive electrode side in Figure 1. [Figure 4] This is a magnified view of the negative electrode side in Figure 1. [Figure 5] It is a perspective view showing the configuration of a wound electrode body according to an embodiment. [Figure 6] It is a plan view of the wound electrode body according to an embodiment as viewed from the Z1 side. [Figure 7] It is a plan view of the wound electrode body according to an embodiment as viewed from the Z2 side. [Figure 8] It is a cross-sectional view taken along line VIII-VIII of FIG. 5. [Figure 9] It is a cross-sectional view taken along line IX-IX of FIG. 5. [Figure 10] It is a plan view of the wound electrode body according to the first modification of an embodiment as viewed from the Z1 side. [Figure 11] It is a plan view of the wound electrode body according to the second modification of an embodiment as viewed from the Z1 side. [Figure 12] It is a plan view of the wound electrode body according to the third modification of an embodiment as viewed from the Z1 side. [Figure 13] It is a plan view of the wound electrode body according to the fourth modification of an embodiment as viewed from the Z1 side. [Figure 14] It is a side view of the wound electrode body according to the fifth modification of an embodiment as viewed from the radially outer side. [Figure 15] It is a side view of the wound electrode body according to the sixth modification of an embodiment as viewed from the radially outer side. [Figure 16] It is a perspective view of the wound electrode body according to the seventh modification of an embodiment.

Embodiments for Carrying Out the Invention

[0019] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals, and the description thereof will not be repeated.

[0020] FIG. 1 is a cross-sectional view showing the overall configuration of a power storage cell 100 according to an embodiment of the present disclosure. The power storage cell 100 is, for example, a lithium-ion battery mounted on a vehicle. Note that the use and type of the power storage cell 100 are not limited to the above example.

[0021] The energy storage cell 100 comprises a wound electrode body 1, a case 2, a positive electrode terminal 3, a positive electrode current collector plate 4, an external gasket 5, an internal gasket 6, a negative electrode current collector plate 7, and a fixing member 8 (see Figure 2). Figure 1 is a cross-sectional view in a direction in which the fixing member 8 is not visible.

[0022] The wound electrode body 1 is housed in case 2. Case 2 has a cylindrical shape. In other words, the energy storage cell 100 is a cylindrical battery. Case 2 is made of copper or aluminum, among other materials.

[0023] The wound electrode body 1 includes a positive electrode plate 10, a negative electrode plate 20, and a separator 30. The separator 30 is provided between the positive electrode plate 10 and the negative electrode plate 20. The separator 30 separates the positive electrode plate 10 (positive electrode active material) and the negative electrode plate 20 (negative electrode active material) while allowing ions (e.g., lithium ions) to move between them. The wound electrode body 1 is composed of an electrode group in which the positive electrode plate 10 and the negative electrode plate 20 are wound with the separator 30 in between. The positive electrode plate 10 and the negative electrode plate 20 are examples of the "first electrode" and "second electrode" of this disclosure, respectively.

[0024] As shown in Figure 2, the wound electrode body 1 is wound such that the positive electrode plate 10, the negative electrode plate 20, and the separator 30 surround the winding axis α. In Figure 2, the wound electrode body 1 is shown in a state where the winding is slightly unwound, making the winding state of the wound electrode body 1 easier to understand.

[0025] Referring again to Figure 1, the positive terminal 3 includes a disk portion 3a and a rivet portion 3b. The rivet portion 3b is connected to the disk portion 3a. The rivet portion 3b is provided so as to extend from the center of the disk portion 3a toward Z2. The positive terminal 3 is made of aluminum.

[0026] As shown in Figure 3, the disc portion 3a is positioned on the upper surface 2a (Z1 side) of the case 2. A through hole 2b is provided in the upper surface 2a of the case 2. The rivet portion 3b extends from the disc portion 3a, which is located outside the case 2, through the through hole 2b to the inside of the case 2.

[0027] The positive electrode current collector plate 4 is housed in the case 2. The positive electrode current collector plate 4 is welded to the unpainted positive electrode portion 11b of the positive electrode plate 10 (described later) on the Z1 side of the wound electrode body 1. As a result, the positive electrode current collector plate 4 is positively charged. The positive electrode current collector plate 4 is welded to the Z2 side end 3c of the rivet portion 3b. As a result, the positive electrode terminal 3 is positively charged.

[0028] The external gasket 5 is positioned between the disc portion 3a of the positive terminal 3 and the upper surface 2a of the case 2. This insulates the positive terminal 3 from the case 2.

[0029] The internal gasket 6 is positioned inside the case 2, between the case 2 and the positive electrode current collector plate 4. This insulates the case 2 from the positive electrode current collector plate 4. The rivet portion 3b is in contact with the positive electrode current collector plate 4 by penetrating the internal gasket 6.

[0030] The positive electrode plate 10 includes a positive electrode current collector 11 and a positive electrode composite layer 12. The positive electrode composite layer 12 is coated on both radial (R-direction) surfaces of the positive electrode current collector 11 (positive electrode coated portion 11a, described later). The positive electrode composite layer 12 faces the separator 30 in the R-direction. The positive electrode current collector 11 and the positive electrode composite layer 12 are examples of the "first current collector" and the "first electrode material layer," respectively.

[0031] For example, aluminum is used for the positive electrode current collector 11. The positive electrode composite layer 12 is formed by coating the surface of the positive electrode current collector 11 with a positive electrode slurry and drying it. The positive electrode slurry is a slurry prepared by kneading the materials of the positive electrode composite layer 12 (such as positive electrode active material and binder) with a solvent. The positive electrode composite layer 12 is in close contact with the separator 30. The thickness of the positive electrode composite layer 12 is, for example, 0.1 μm or more and 1000 μm or less.

[0032] The positive electrode current collector 11 includes a positive electrode coated portion 11a and a positive electrode uncoated portion 11b. The positive electrode coated portion 11a is the portion of the positive electrode current collector 11 to which the positive electrode composite material layer 12 is coated. The positive electrode coated portion 11a is sandwiched between the separators 30. The positive electrode coated portion 11a and the positive electrode uncoated portion 11b are examples of the "first coated portion" and "first uncoated portion" as described herein.

[0033] The uncoated positive electrode portion 11b is the portion of the positive electrode current collector 11 in which the positive electrode composite material layer 12 is not coated. The uncoated positive electrode portion 11b is located on the Z1 side of the coated positive electrode portion 11a. Specifically, the uncoated positive electrode portion 11b protrudes from the coated positive electrode portion 11a on the Z1 side. Note that the Z1 side is an example of the "one side in the axial direction" in this disclosure.

[0034] The unpainted portion 11b of the positive electrode includes a portion 11c extending along the Z direction and a portion 11d extending along the R direction. The unpainted portion 11b of the positive electrode is bent radially inward. The unpainted portion 11b of the positive electrode is bent into an L shape. Portion 11d of the unpainted portion 11b of the positive electrode is in contact with the positive electrode current collector plate 4. As a result, the positive electrode current collector plate 4 is positively charged. The unpainted portion 11b (portion 11d) of the positive electrode is joined to the positive electrode current collector plate 4 by welding.

[0035] Multiple uncoated positive electrode portions 11b are arranged in a row along the winding direction. Slits 11g (see Figure 5) are provided between adjacent uncoated positive electrode portions 11b in the winding direction. Among the multiple uncoated positive electrode portions 11b, those adjacent in the R direction are arranged to partially overlap each other.

[0036] As shown in Figure 4, the negative electrode current collector plate 7 is housed in the case 2. The negative electrode current collector plate 7 is welded to the uncoated negative electrode portion 21b of the negative electrode plate 20 (described later) on the Z2 side of the wound electrode body 1. As a result, the negative electrode current collector plate 7 is negatively charged. The negative electrode current collector plate 7 is in contact with the case 2. As a result, the case 2 is negatively charged.

[0037] The negative electrode plate 20 includes a negative electrode current collector 21 and a negative electrode composite layer 22. The negative electrode composite layer 22 is coated on both radial (R-direction) surfaces of the negative electrode current collector 21 (negative electrode coated portion 21a, described later). The negative electrode composite layer 22 faces the separator 30 in the R-direction. The negative electrode current collector 21 and the negative electrode composite layer 22 are examples of the "second current collector" and "second electrode material layer" of this disclosure, respectively.

[0038] The negative electrode current collector 21 is made of a material such as copper. The negative electrode composite layer 22 is formed by coating the surface of the negative electrode current collector 21 with a negative electrode slurry and drying it. The negative electrode slurry is a slurry prepared by kneading the materials of the negative electrode composite layer 22 (such as negative electrode active material and binder) with a solvent. The negative electrode composite layer 22 is in close contact with the separator 30. The thickness of the negative electrode composite layer 22 is, for example, 0.1 μm or more and 1000 μm or less.

[0039] The negative electrode current collector 21 includes a negative electrode coated portion 21a and a negative electrode uncoated portion 21b. The negative electrode coated portion 21a is the portion of the negative electrode current collector 21 to which the negative electrode composite material layer 22 is coated. The negative electrode coated portion 21a is sandwiched between the separators 30. The negative electrode coated portion 21a and the negative electrode uncoated portion 21b are examples of the "second coated portion" and "second uncoated portion" of this disclosure, respectively.

[0040] The uncoated negative electrode portion 21b is the portion of the negative electrode current collector 21 in which the negative electrode composite material layer 22 is not coated. The uncoated negative electrode portion 21b is located on the Z2 side of the coated negative electrode portion 21a. Specifically, the uncoated negative electrode portion 21b protrudes from the coated negative electrode portion 21a on the Z2 side. Note that the Z2 side is an example of the "other axial side" in this disclosure.

[0041] The unpainted portion 21b of the negative electrode includes a portion 21c extending along the Z direction and a portion 21d extending along the R direction. The unpainted portion 21b of the negative electrode is bent radially inward. The unpainted portion 21b of the negative electrode is bent into an L shape. Portion 21d of the unpainted portion 21b of the negative electrode is in contact with the negative electrode current collector plate 7. As a result, the negative electrode current collector plate 7 is negatively charged. The unpainted portion 21b (portion 21d) of the negative electrode is joined to the negative electrode current collector plate 7 by welding.

[0042] Furthermore, multiple uncoated negative electrode portions 21b are arranged in a row along the winding direction. Slits 21g (see Figure 5) are provided between adjacent uncoated negative electrode portions 21b in the winding direction. In addition, among the multiple uncoated negative electrode portions 21b, those adjacent in the R direction are arranged to partially overlap each other.

[0043] As shown in Figure 5, the wound electrode body 1 includes an end face 1a, an end face 1b, a circumferential surface 1c, and a terminal portion 1d. End face 1a is the Z1-side end face of the wound electrode body 1. End face 1b is the Z2-side end face of the wound electrode body 1. The circumferential surface 1c is the outer circumferential surface of the wound electrode body 1 located between end face 1a and end face 1b. The terminal portion 1d is the end portion of the winding of the wound electrode body 1.

[0044] In conventional energy storage cell configurations, fixing tape is sometimes applied to the sides of the wound electrode body to maintain its winding state. Furthermore, to restrict the movement of the wound electrode body, the space between the sides of the wound electrode body and the inner surface of the case is small. Therefore, when the wound electrode body expands, the tape and the case interfere with each other, creating localized pressure at the point where the tape is applied.

[0045] Therefore, in this embodiment, as shown in Figures 2 and 5, the fixing member 8 is provided on the end face 1a. The fixing member 8 is a member that fixes the wound electrode body 1 so as to maintain the wound state of the wound electrode body 1. The end face 1a is formed by an uncoated positive electrode portion 11b that is provided to be wound around the winding axis α.

[0046] In other words, the fixing member 8 is provided on the uncoated portion 11b of the positive electrode. Specifically, the fixing member 8 is attached to the Z1-side surface of portion 11d of the uncoated portion 11b of the positive electrode.

[0047] Two fixing members 8 are provided on the end face 1a. The two fixing members 8 on the end face 1a are provided on opposite sides (facing each other) with respect to the winding axis α. That is, the two fixing members 8 on the end face 1a are provided on a straight line passing through the winding axis α.

[0048] The fixing member 8 is also provided on the end face 1b. The end face 1b is formed by the unpainted negative electrode portion 21b, which is provided to wind around the winding axis α. That is, the fixing member 8 is provided on the unpainted negative electrode portion 21b. Specifically, the fixing member 8 is attached to the Z2 side surface of portion 21d of the unpainted negative electrode portion 21b.

[0049] Two fixing members 8 are provided on the end face 1b. The two fixing members 8 on the end face 1b are located on opposite sides of the winding axis α. That is, the two fixing members 8 on the end face 1b are located on a straight line passing through the winding axis α.

[0050] The fixing members 8 may be provided one or more times on each of the end faces 1a and 1b. Furthermore, the number of fixing members 8 provided on end face 1a may differ from the number of fixing members 8 provided on end face 1b.

[0051] The fixing member 8 at end face 1a is positioned so as to overlap (coincide with) the fixing member 8 at end face 1b in the Z direction.

[0052] One of the two fixing members 8 at each of the end faces 1a and 1b is provided at the terminal portion 1d. Specifically, the fixing member 8 is provided at a position that overlaps with the terminal portion 1d in the circumferential direction of the wound electrode body 1. However, the fixing member 8 may not be provided at a position that overlaps with the terminal portion 1d in the circumferential direction, but rather at a position near the terminal portion 1d in the circumferential direction.

[0053] As shown in Figure 6, the fixing member 8 is attached to the portion 11e of the uncoated positive electrode portion 11b (part 11d) that is located on the outer peripheral edge 1e of the wound electrode body 1. That is, portion 11e is the uncoated positive electrode portion 11b that protrudes toward Z1 from the coated positive electrode portion 11a, which is wound most radially outward on the positive electrode current collector 11. Note that in Figure 6, the fixing member 8 is shown with diagonal lines.

[0054] Furthermore, the fixing member 8 is attached to multiple portions 11f of the uncoated positive electrode portion 11b (portion 11d) that are arranged radially inward relative to portion 11e when viewed from the Z1 side. Portion 11f is the uncoated positive electrode portion 11b that protrudes toward Z1 from the positive electrode coated portion 11a that is wound radially inward from the positive electrode coated portion 11a that is wound radially outward. In other words, portion 11f is the portion that protrudes from the positive electrode coated portion 11a at a position closer to the winding axis α than the position where portion 11e protrudes from the positive electrode coated portion 11a.

[0055] The fixing member 8 is provided across a portion 11e and multiple portions 11f that are arranged radially. As a result, portions 11e and multiple portions 11f are bonded to each other by the adhesive layer 8d described later. Note that radially adjacent uncoated positive electrode portions 11b (portion 11e and portion 11f / portions 11f together) are provided so as to partially overlap in the Z direction.

[0056] The fixing member 8 is provided between the winding axis α and the circumferential surface 1c (outer edge 1e of the winding electrode body 1) so as to extend along the radial direction of the winding electrode body 1. The fixing member 8 is provided so as to extend radially inward from portion 11e. The fixing member 8 has a rectangular shape (see Figure 6) with the radially extending side as the longer side. If the diameter r of the case 2 (see Figure 1) is, for example, 46 mm, it is preferable that the radial length L1 of the fixing member 8 (see Figure 6) is 1 mm or more and 23 mm or less (i.e., less than or equal to the radius of the case 2). This makes it possible to suppress interference between the fixing member 8 and the case 2. The diameter r may be the outer diameter of the case 2.

[0057] The fixing member 8 is positioned closer to the circumferential surface 1c than to the winding axis α. Specifically, when viewed from one axial side (Z1 side), the distance D1 between the radially outer end 8a of the fixing member 8 and the circumferential surface 1c (outer edge 1e) is smaller than the distance D2 between the radially inner end 8b of the fixing member 8 and the winding axis α. Furthermore, when viewed from the Z1 side, distance D1 is smaller than the distance D3 between the inner circumferential edge 11h of the uncoated positive electrode portion 11b and the end 8b. Note that "viewed from the Z1 side" means viewing the wound electrode body 1 from a point P1 (see Figure 5) on the winding axis α on the Z1 side of the wound electrode body 1.

[0058] As can be seen from the above explanation, the wound electrode body 1 includes an exposed portion where the fixing member 8 is not positioned and is exposed when viewed along the axial direction. That is, the fixing member 8 is provided on a part of the wound electrode body 1 when viewed from the Z1 side. In the example shown in Figure 6, the exposed portion refers to the area other than the region where the fixing member 8 is provided.

[0059] The negative electrode side is configured similarly. Specifically, as shown in Figure 7, the fixing member 8 is attached to the portion 21e of the uncoated negative electrode portion 21b (part 21d) that is located on the outer peripheral edge 1e of the wound electrode body 1. That is, portion 21e is the uncoated negative electrode portion 21b that protrudes toward Z2 from the coated negative electrode portion 21a, which is wound most radially outward on the negative electrode current collector 21. Note that in Figure 7, the fixing member 8 is shown with diagonal lines for clarity.

[0060] Furthermore, the fixing member 8 is attached to multiple portions 21f of the uncoated negative electrode portion 21b (portion 21d) that are arranged radially inward relative to portion 21e when viewed from the Z2 side. Portion 21f is the uncoated negative electrode portion 21b that protrudes toward the Z2 side from the negative electrode coated portion 21a that is wound radially inward from the negative electrode coated portion 21a that is wound radially outward. In other words, portion 21f is the portion that protrudes from the negative electrode coated portion 21a at a position closer to the winding axis α than the position where portion 21e protrudes from the negative electrode coated portion 21a. Note that "viewed from the Z2 side" means viewing the wound electrode body 1 from point P2 (see Figure 5) on the winding axis α on the Z1 side of the wound electrode body 1.

[0061] The fixing member 8 is provided across a portion 21e and multiple portions 21f that are arranged radially. As a result, portions 21e and multiple portions 21f are bonded to each other by the adhesive layer 8d described later. Note that radially adjacent uncoated negative electrode portions 21b (portion 21e and portion 21f / portions 21f together) are provided so as to partially overlap in the Z direction.

[0062] The position and shape of the fixing member 8 on end face 1b are the same as those of the fixing member 8 on end face 1a described above, so a repeated explanation will be omitted.

[0063] Figure 8 is a cross-sectional view along the line VIII-VIII in Figure 5. The fixing member 8 includes a base material 8c and an adhesive layer 8d provided on the base material 8c. The adhesive layer 8d is applied to the surface of the base material 8c. The fixing member 8 is positioned on the wound electrode body 1 with the adhesive layer 8d facing the wound electrode body 1 side (Z2 side). As a result, the radially aligned uncoated positive electrode portions 11b (parts 11e and 11f / parts 11f together) are bonded to each other by the adhesive layer 8d. Note that the portions in contact with the fixing member 8 (11e, 11f) are not in contact with the positive electrode current collector plate 4.

[0064] Figure 9 is a cross-sectional view along the line IX-IX in Figure 5. The fixing member 8 is positioned on the wound electrode body 1 with the adhesive layer 8d facing the wound electrode body 1 side (Z1 side). As a result, the radially aligned uncoated negative electrode portions 21b (part 21e and part 21f / part 21f together) are bonded to each other by the adhesive layer 8d. Note that the portions in contact with the fixing member 8 (21e, 21f) are not in contact with the negative electrode current collector plate 7.

[0065] In this embodiment, the base material 8c is formed of an elastically deformable resin. That is, the base material 8c is formed of a resin with a low modulus of elasticity. The type of base material 8c is determined by considering the amount of expansion of the wound electrode body 1 (for example, the negative electrode plate 20). Specifically, a base material 8c that can deform (within an acceptable range) greater than the above-mentioned expansion amount is selected. For example, the base material 8c may be formed of epoxy resin.

[0066] As described above, in this embodiment, the fixing member 8 is provided on the end face 1a (1b) of the wound electrode body 1. This allows the fixing member 8, which maintains the wound state of the wound electrode body 1, to be positioned on one axial side (the other side) of the wound electrode body 1, where there is relatively ample space. This prevents interference between the fixing member 8 and the case 2 even if the wound electrode body 1 expands. As a result, the wound state of the wound electrode body can be maintained while suppressing the generation of localized pressure on the wound electrode body.

[0067] In the above embodiment, an example was shown in which the fixing member 8 is provided on portion 11e of the outer peripheral edge 1e (end portion 1d) of the wound electrode body 1, but the disclosure is not limited thereto. The fixing member 8 does not have to be provided on portion 11e of the outer peripheral edge 1e (end portion 1d). For example, in the example shown in Figure 10, the fixing member 18 is provided radially inward from portion 11e of the outer peripheral edge 1e. The negative electrode side may be configured similarly.

[0068] In the above embodiment, an example was shown in which the fixing member 8 is provided at a position closer to the circumferential surface 1c than the winding axis α, but the disclosure is not limited thereto. For example, as shown in Figure 11, the fixing member 28 may be positioned closer to the winding axis α than the circumferential surface 1c (outer edge 1e). The negative electrode side may also be configured similarly.

[0069] In the above embodiment, an example was shown in which the fixing member 8 is provided to extend in the radial direction, but the disclosure is not limited thereto. The fixing member 8 does not have to extend in the radial direction. For example, in the example shown in Figure 12, the fixing member 8 is provided to extend in directions intersecting the radial and circumferential directions, respectively. The negative electrode side may be configured similarly.

[0070] In the above embodiment, an example was shown in which a rectangular fixing member 8 is formed linearly along the radial direction, but the disclosure is not limited thereto. For example, as shown in Figure 13, a plurality of fixing members 38 may be arranged in a line along the radial direction. Also, the fixing members may be circular (perfect circles, ellipses, and oblongs, etc.) instead of rectangular. Note that only one of the plurality of fixing members 38 in Figure 13 may be provided.

[0071] In the above embodiment, an example is shown in which a fixing member 8 is formed on each of the end faces 1a and 1b, but the disclosure is not limited thereto. The fixing member 8 may be provided on only one of the end faces 1a and 1b. Figure 14 illustrates an example in which the fixing member 8 is provided only on the end face 1a.

[0072] In the above embodiment, an example was shown in which a fixing member 8 is provided on a tabless type wound electrode body 1 in which uncoated portions (11b, 21b) protrude axially from coated portions (11a, 21a), but the disclosure is not limited thereto. As shown in Figure 15, a fixing member 8 may be provided on a wound electrode body 31 including a tab lead 111 attached to a positive electrode plate 110 and a tab lead 121 attached to a negative electrode plate 120.

[0073] In the above embodiment, an example was shown in which the uncoated portion 11b of the positive electrode and the uncoated portion 21b of the negative electrode are each bent radially inward, but the disclosure is not limited thereto. At least one of the uncoated portion 11b of the positive electrode and the uncoated portion 21b of the negative electrode may be bent radially outward.

[0074] In the above embodiment, an example was shown in which slits 11g are provided between multiple uncoated positive electrode portions 11b, but the disclosure is not limited thereto. Slits are not provided in the uncoated positive electrode portions. That is, the positive electrode current collector may include a single uncoated positive electrode portion wound around the winding axis α. The same may apply to the negative electrode side.

[0075] In the above embodiment, an example was shown in which multiple uncoated positive electrode portions 11b, including portions 11c and 11d, are provided, but the disclosure is not limited thereto. Multiple portions 11d may be connected to a single portion (corresponding to portion 11c) extending in the winding direction. The same may apply to the negative electrode side.

[0076] In the above embodiment, an example was shown in which two fixing members 8 are arranged side by side in the radial direction, but the disclosure is not limited thereto. As shown in Figure 16, one fixing member 48 may extend radially through the center of the winding of the wound electrode body 1. When the diameter r of the case 2 (see Figure 1) is 46 mm, it is preferable that the radial length L2 of the fixing member 48 is 46 mm or less. This makes it possible to suppress interference between the fixing member 48 and the case 2.

[0077] Furthermore, the configurations of the above embodiments and each of the above modified examples may be combined with each other.

[0078] The embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of this disclosure is indicated by the claims rather than by the description of the embodiments above, and all modifications within the meaning and scope equivalent to the claims are intended to be included. [Explanation of symbols]

[0079] 1. Winded electrode body, 1a. End face (first end face), 1b. End face (second end face), 1c. Circumferential surface, 1d. End portion, 2. Case, 8. Fixing member, 8a. Base material, 8b. Adhesive layer, 10. Positive electrode plate (first electrode), 11. Positive electrode current collector (first current collector), 11a. Positive electrode coated part (first coated part), 11b. Positive electrode uncoated part (first uncoated part), 12. Positive electrode composite layer (first electrode material layer), 20. Negative electrode plate (second electrode), 21. Negative electrode current collector (second current collector), 21a. Negative electrode coated part (second coated part), 21b. Negative electrode uncoated part (second uncoated part), 22. Negative electrode composite layer (second electrode material layer), 30. Separator, 100. Energy storage cell, L1. Length, R. Direction (radial direction), r. Diameter, Z. Direction (axial direction), α Winding axis.

Claims

1. A wound electrode body including a first electrode, a second electrode, and a separator disposed between the first electrode and the second electrode, The device comprises a fixing member for fixing the wound electrode body so that the wound state of the wound electrode body is maintained, The wound electrode body is wound such that the first electrode, the second electrode, and the separator surround the winding axis. The wound electrode body includes a first end face on one side in the axial direction from which the winding axis extends, and a second end face on the other side in the axial direction. The wound electrode body includes a circumferential surface located between the first end face and the second end face. The aforementioned fixing member is At least the first end face is provided, A storage cell provided between the winding axis and the circumferential surface, extending along the radial direction of the wound electrode body but not extending to the circumferential surface.

2. The energy storage cell according to claim 1, wherein the fixing member is also provided on the second end face.

3. The energy storage cell according to claim 1 or 2, wherein the fixing member is provided at a position closer to the circumferential surface than the winding axis.

4. The case further comprises a cylindrical shape for housing the wound electrode body, The energy storage cell according to claim 1 or 2, wherein the length of the fixing member in the radial direction is less than or equal to the radius of the case.

5. The wound electrode body includes the end portion of the winding, The energy storage cell according to claim 1 or 2, wherein the fixing member is provided adjacent to the end portion in the radial direction of the wound electrode body, when viewed from a position spaced apart from the wound electrode body in the axial direction.

6. The energy storage cell according to claim 1 or 2, wherein the wound electrode body includes an exposed portion that is exposed and does not have the fixing member when viewed along the axial direction.

7. The fixing member includes a base material and an adhesive layer provided on the base material. The energy storage cell according to claim 1 or 2, wherein the substrate is formed of an elastically deformable resin.

8. The first electrode includes a first current collector and a first electrode material layer coated on a part of the first current collector and facing the separator in the radial direction of the wound electrode body. The first current collector has a first coated portion on which the first electrode material layer is applied, and a first uncoated portion located on the first end face on one side in the axial direction from the first coated portion, and on which the first electrode material layer is not applied. The energy storage cell according to claim 1 or 2, wherein the fixing member is provided in the first unpainted portion.

9. The second electrode includes a second current collector and a second electrode material layer coated on a portion of the second current collector and facing the separator in the radial direction of the wound electrode body. The second current collector has a second coated portion on which the second electrode material layer is applied, and a second uncoated portion located on the second end face on the other side in the axial direction from the second coated portion, and on which the second electrode material layer is not applied. The energy storage cell according to claim 2, wherein the fixing member is provided in the second unpainted portion.

10. A wound electrode body including a first electrode, a second electrode, and a separator disposed between the first electrode and the second electrode, The device comprises a fixing member for fixing the wound electrode body so that the wound state of the wound electrode body is maintained, The wound electrode body is wound such that the first electrode, the second electrode, and the separator surround the winding axis. The wound electrode body includes a first end face on one side in the axial direction from which the winding axis extends, and a second end face on the other side in the axial direction. The aforementioned fixing member is At least the first end face is provided, It comprises a base material and an adhesive layer provided on the base material, The aforementioned substrate is formed of an elastically deformable resin, and is used to create an energy storage cell.

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