Electricity storage unit

Abstract

The present disclosure relates to a power storage unit. A positive electrode sheet (first electrode sheet) of a power storage cell includes a long side (first long side) located at an end portion on a Z1 side (one side in an axial direction). The negative electrode sheet (second electrode sheet) includes a long side (second long side) located at an end portion on the Z1 side. The positive electrode sheet includes a positive electrode current collector (a first current collector) and a positive electrode composite material layer (a first electrode material layer). A positive electrode uncoated portion of a positive electrode current collector is formed on a long side and includes a plurality of sheet portions (first sheet portions) arranged in an X direction (winding direction). An insulating part (a first insulating part, an insulating member) is formed on the long side of the negative electrode sheet.

Description

Technical Field

[0001] The present disclosure relates to a power storage unit. Background Art

[0002] A battery cell having an electrode body obtained by spirally winding electrode sheets (a positive electrode sheet and a negative electrode sheet) is disclosed in U.S. Patent Application Publication No. 2016 / 0104875. The electrode sheets are wound in a state where the positive electrode sheet and the negative electrode sheet overlap with each other with a separator therebetween. Summary of the Utility Model

[0003] Here, although not described in the above U.S. Patent Application Publication No. 2016 / 0104875, a plurality of tab portions (metal tabs) are sometimes provided at the axial end portions of the electrode sheets. For example, the plurality of tab portions may be bent due to bending of the plurality of tab portions of the positive electrode sheet (the first electrode sheet), resulting in contact between the plurality of tab portions and the negative electrode sheet (the second electrode sheet).

[0004] The present disclosure has been completed to solve the above problems, and an object thereof is to provide a power storage unit capable of suppressing contact between a plurality of tab portions provided at the axial end portion of the first electrode sheet and the second electrode sheet.

[0005] A power storage unit according to an aspect of the present disclosure includes: a wound electrode body including a first electrode sheet, a second electrode sheet, and a separator disposed between the first electrode sheet and the second electrode sheet; and an insulating member. The first electrode sheet and the second electrode sheet are each formed to be long in the winding direction of the wound electrode body. The first electrode sheet includes a first long side located at one end on the axis extending in the winding axis direction of the wound electrode body. The second electrode sheet includes a second long side located at one end on the axis. The first electrode sheet includes: a first electrode material layer; and a first current collector including a first coated portion on which the first electrode material layer is formed and a first uncoated portion on which the first electrode material layer is not coated. The first uncoated portion is formed on the first long side and includes a plurality of first tab portions arranged in the winding direction. The insulating member includes a first insulating portion formed on the second long side.

[0006] In the power storage unit according to an aspect of the present disclosure, as described above, a plurality of tab portions are provided on the first long side at one axial side end portion of the first electrode sheet, and a first insulating portion is formed on the second long side at one axial side end portion of the second electrode sheet. Thus, even if the plurality of first tab portions are bent toward the second electrode sheet side, contact (conductivity) between the plurality of first tab portions and the second electrode sheet can be suppressed by the first insulating portion.

[0007] In the power storage unit according to the above - mentioned one aspect, preferably, the first electrode plate includes a third long side at an end on the other side in the axial direction. The second electrode plate includes a fourth long side at an end on the other side in the axial direction. The second electrode plate includes: a second electrode material layer; and a second current collector including a second coated portion where the second electrode material layer is formed and a second uncoated portion where the second electrode material layer is not coated. The second uncoated portion is formed on the fourth long side and includes a plurality of second sheet portions arranged in the winding direction. The insulating member includes a second insulating portion formed on the third long side. If configured in this way, even if the plurality of second sheet portions are bent toward the first electrode plate side, contact (conductivity) between the plurality of second sheet portions and the first electrode plate can be suppressed by the second insulating portion.

[0008] In the power storage unit according to the above - mentioned one aspect, preferably, the insulating member is formed of a porous material. If configured in this way, when the electrolyte is injected into the wound electrode body from one side in the axial direction, the electrolyte can be introduced into the wound electrode body through the insulating member made of the porous material.

[0009] In this case, preferably, the insulating member is formed continuously along the winding direction. If configured in this way, contact between the electrode plate and the sheet portion can be more reliably suppressed.

[0010] In the power storage unit according to the above - mentioned one aspect, preferably, the insulating member is formed intermittently along the winding direction. If configured in this way, gaps are generated between the insulating members. Therefore, when the electrolyte is injected into the wound electrode body from one side in the axial direction, entry of the electrolyte can be easily prevented from being obstructed by the insulating members.

[0011] According to the present disclosure, contact between a plurality of sheet portions provided at the axial end of the first electrode plate and the second electrode plate can be suppressed. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Features, advantages, and technical and industrial significance of exemplary embodiments of the present utility model will be described below with reference to the accompanying drawings, in which like reference numerals represent like elements.

[0013] Figure 1 It is a cross - sectional view showing the configuration of a power storage unit according to an embodiment.

[0014] Figure 2 It is a schematic perspective view showing the configuration of a wound electrode body according to an embodiment.

[0015] Figure 3 It is a plan view showing the configuration of a positive current collector plate according to an embodiment.

[0016] Figure 4 It is a plan view showing the configuration of a negative current collector plate according to an embodiment.

[0017] Figure 5 is Figure 1 a partial enlarged view near the positive current collector plate of

[0018] Figure 6 is Figure 1 a partial enlarged view near the negative current collector plate of

[0019] Figure 7 is a diagram showing the configuration of the unwound state of the positive electrode sheet and the negative electrode sheet according to one embodiment.

[0020] Figure 8 is a diagram showing the configuration of the unwound state of the positive electrode sheet and the negative electrode sheet according to a modified example of one embodiment. Detailed Embodiment

[0021] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying Figure 1 drawings. In addition, the same or corresponding parts in the drawings are denoted by the same reference numerals, and their description will not be repeated.

[0022] The power storage unit 100 includes a wound electrode body 1, a housing 2, a positive terminal 3, a positive current collector plate 4, an external gasket 5, an internal gasket 6, a negative current collector plate 7, a polymer ring 8, and a sealing plug 9.

[0023] The wound electrode body 1 is housed in the housing 2. The housing 2 has a cylindrical shape. The wound electrode body 1 is wound so as to have the same cylindrical shape as the housing 2. That is, the power storage unit 100 is a cylindrical battery. In addition, the housing 2 is formed of copper or aluminum or the like.

[0024] The housing 2 includes a top plate portion 2a, a peripheral wall portion 2c, and a sealing plate 2d. The peripheral wall portion 2c is provided on the outer peripheral side of the wound electrode body 1 and has a cylindrical shape. The top plate portion 2a is connected to the end portion on the Z1 side of the peripheral wall portion 2c. The top plate portion 2a and the peripheral wall portion 2c are integrally formed. The sealing plate 2d is connected to the end portion on the Z2 side of the peripheral wall portion 2c. The sealing plate 2d covers the opening on the Z2 side of the peripheral wall portion 2c. A tightening portion 2e that tightens (chisels) against the outer peripheral edge of the sealing plate 2d is formed at the end portion on the Z2 side of the peripheral wall portion 2c. The tightening portion 2e is formed in an annular shape.

[0025] The wound electrode body 1 includes a positive electrode sheet 10, a negative electrode sheet 20, and a separator 30. The separator 30 is disposed between the positive electrode sheet 10 and the negative electrode sheet 20. The separator 30 allows ions (such as lithium ions) to move back and forth between the positive electrode sheet 10 (positive electrode active material) and the negative electrode sheet 20 while separating the positive electrode sheet 10 and the negative electrode sheet 20. The wound electrode body 1 is composed of a plate group obtained by winding the positive electrode sheet 10 and the negative electrode sheet 20 with the separator 30 therebetween. In addition, the positive electrode sheet 10 and the negative electrode sheet 20 are examples of the "first electrode sheet" and the "second electrode sheet" of the present disclosure, respectively.

[0026] As Figure 2 shown, the wound electrode body 1 is wound in such a manner that the positive electrode sheet 10, the negative electrode sheet 20, and the separator 30 surround the periphery of the winding axis α. In Figure 2 , in order to easily understand the winding state of the wound electrode body 1, a state in which the winding of the wound electrode body 1 is slightly loosened is illustrated.

[0027] Referring again to Figure 1 , the positive terminal 3 includes a disk portion 3a and a riveted portion 3b. The disk portion 3a is exposed by being disposed outside the housing 2. The riveted portion 3b is connected to the disk portion 3a. The riveted portion 3b is disposed so as to extend from the center of the disk portion 3a toward the Z2 side. In addition, the positive terminal 3 is formed of aluminum.

[0028] The disk portion 3a is disposed on the top plate 2a of the housing 2. The top plate portion 2a is provided at the Z1-side end of the housing 2. The top plate 2a is disposed so as to be orthogonal to the Z direction. A through hole 2b (refer to Figure 5 ) is provided in the top plate 2a. The riveted portion 3b extends from the disk portion 3a disposed outside the housing 2 through the through hole 2b into the interior of the housing 2. In addition, the Z direction is an example of the "axial direction" of the present disclosure.

[0029] The positive current collector plate 4 is housed in the housing 2. The positive current collector plate 4 (a sheet portion 4d described later) is welded to a positive electrode uncoated portion 11b of the positive electrode sheet 10 described later. Thereby, the positive current collector plate 4 is positively charged. The positive current collector plate 4 is welded to the end portion 3c on the Z2 side of the riveted portion 3b. Thereby, the positive terminal 3 is positively charged.

[0030] The external gasket 5 is disposed outside the housing 2. Specifically, the external gasket 5 is disposed between the disk portion 3a of the positive terminal 3 and the top plate portion 2a of the housing 2. Thereby, the positive terminal 3 and the housing 2 are insulated.

[0031] The internal gasket 6 is disposed inside the housing 2. Specifically, the internal gasket 6 is disposed between the housing 2 and the positive current collector plate 4. Thereby, the housing 2 and the positive current collector plate 4 are insulated. In addition, the riveted portion 3b contacts the positive current collector plate 4 through the internal gasket 6.

[0032] The negative electrode current collector plate 7 is housed in the outer casing 2. The negative electrode current collector plate 7 (the piece portion 7d described later) is welded to the negative electrode uncoated portion 21b of the negative electrode plate 20 described later. Thus, the negative electrode current collector plate 7 is negatively charged. In addition, the negative electrode current collector plate 7 is in contact with the outer casing 2. Thus, the outer casing 2 is negatively charged.

[0033] The polymer ring 8 is provided between the outer peripheral edge of the sealing plate 2d and the tightening portion 2e formed in the peripheral wall portion 2c. The polymer ring 8 has an annular shape.

[0034] The sealing plug 9 plugs the through hole 2f provided at the center of the sealing plate 2d. The sealing plug 9 penetrates the through hole 7g provided at the center of the negative electrode current collector plate 7 together with the through hole 2f.

[0035] Figure 3 It is a plan view of the positive electrode current collector plate 4. The positive electrode current collector plate 4 has a disc shape. The positive electrode current collector plate 4 includes a central portion 4a, spokes 4b, an outer peripheral edge portion 4c, and a piece portion 4d.

[0036] The central portion 4a is provided at the center of the positive electrode current collector plate 4. The riveting portion 3b is joined to the central portion 4a. The spokes 4b are provided so as to extend radially outward from the central portion 4a. Six spokes 4b are provided at equal angular intervals around the central portion 4a of the positive electrode current collector plate 4.

[0037] The outer peripheral edge portion 4c is provided at the outer peripheral edge of the positive electrode current collector plate 4. The six spokes 4b connect the outer peripheral edge portion 4c and the central portion 4a respectively. The spokes 4b are formed so as to flex in the Z direction. In addition, the central portion 4a in the positive electrode current collector plate 4 moves (displaces) most greatly in the Z direction.

[0038] Through holes 4e are formed between the spokes 4b adjacent to each other in the circumferential direction. That is, six through holes 4e are formed. Piece portions 4d are provided inside each of the six through holes 4e. The six piece portions 4d are connected to the outer peripheral edge portion 4c through connecting portions 4f respectively. In addition, the six piece portions 4d each have a shape with a tapered tip as going radially inward.

[0039] Figure 4 It is a plan view of the negative electrode current collector plate 7. The negative electrode current collector plate 7 has a disc shape. The negative electrode current collector plate 7 includes a central portion 7a, spokes 7b, an outer peripheral edge portion 7c, and a piece portion 7d.

[0040] The central portion 7a is provided at the center of the negative electrode current collector plate 7. The spokes 7b are provided so as to extend radially outward from the central portion 7a. Six spokes 7b are provided at equal angular intervals around the central portion 7a of the negative electrode current collector plate 7.

[0041] The outer peripheral portion 7c is provided at the outer periphery of the negative current collector plate 7. Six spokes 7b connect the outer peripheral portion 7c and the central portion 7a respectively. Each spoke 7b is formed so as to be flexed in the Z direction. The outer peripheral portion 7c in the negative current collector plate 7 moves (displaces) most largely in the Z direction.

[0042] Through holes 7e are formed between the spokes 7b adjacent to each other in the circumferential direction. That is, six through holes 7e are formed. Piece portions 7d are provided at positions corresponding to the six through holes 7e respectively. Specifically, the six piece portions 7d are respectively arranged inside the corresponding through holes 7e. The six piece portions 7d are respectively connected to the central portion 7a through connection portions 7f. In addition, the six piece portions 7d respectively have a shape with a tapered tip as going toward the radially inner side.

[0043] As Figure 5 shown, the positive electrode plate 10 includes a positive electrode current collector 11 and a positive electrode composite material layer 12. The positive electrode composite material layer 12 is coated on both sides in the radial direction (R direction) of the positive electrode current collector 11 (the positive electrode coating portion 11a described later). The positive electrode composite material layer 12 is in close contact with the separator 30. In addition, the positive electrode current collector 11 and the positive electrode composite material layer 12 are respectively examples of the "first current collector" and the "first electrode material layer".

[0044] The positive electrode current collector 11 is formed of, for example, aluminum or the like. The positive electrode composite material layer 12 is formed by coating a positive electrode paste on the surface of the positive electrode current collector 11 and drying it. The positive electrode paste is a paste prepared by kneading the materials (positive electrode active material, binder, etc.) of the positive electrode composite material layer 12 and a solvent. The positive electrode composite material layer 12 is in close contact with the separator 30. The thickness of the positive electrode composite material layer 12 is, for example, 0.1 μm or more and 1000 μm or less.

[0045] The positive electrode current collector 11 includes a positive electrode coating portion 11a and a positive electrode uncoated portion 11b. The positive electrode coating portion 11a is the portion of the positive electrode current collector 11 coated with the positive electrode composite material layer 12. In other words, the positive electrode coating portion 11a is the portion covered by the positive electrode composite material layer 12 and not exposed. In addition, the positive electrode coating portion 11a and the positive electrode uncoated portion 11b are respectively examples of the "first coating portion" and the "first uncoated portion" of the present disclosure.

[0046] The positive electrode uncoated portion 11b is the portion of the positive electrode current collector 11 that is not covered by the positive electrode composite material layer 12 and the insulating portion 15 described later and is exposed. The positive electrode uncoated portion 11b is located on the Z1 side with respect to the positive electrode coating portion 11a. Specifically, the positive electrode uncoated portion 11b protrudes from the positive electrode coating portion 11a toward the Z1 side. In addition, the Z1 side is an example of the "one side in the axial direction" of the present disclosure.

[0047] The uncoated portion 11b of the positive electrode is bent radially inward by contacting the positive electrode current collector plate 4 disposed on the Z1 side. As a result, the positive electrode current collector plate 4 becomes positively charged. In addition, the uncoated portion 11b of the positive electrode and the positive electrode current collector plate 4 are joined by welding.

[0048] The uncoated portion 11b of the positive electrode includes a plurality of sheet portions 11c. The plurality of sheet portions 11c are arranged along the winding direction of the wound electrode body 1. In addition, the sheet portion 11c is an example of the "first sheet portion" of the present disclosure.

[0049] The negative electrode sheet 20 includes a negative electrode current collector 21 and a negative electrode composite material layer 22. The negative electrode composite material layer 22 is coated on both radial (R direction) sides of the negative electrode current collector 21 (the negative electrode coated portion 21a described later). The negative electrode composite material layer 22 is in close contact with the separator 30. In addition, the negative electrode current collector 21 and the negative electrode composite material layer 22 are examples of the "second current collector" and the "second electrode material layer" of the present disclosure, respectively.

[0050] The negative electrode current collector 21 is formed of, for example, copper or the like. The negative electrode composite material layer 22 is formed by coating a negative electrode paste on the surface of the negative electrode current collector 21 and drying it. The negative electrode paste is a paste prepared by kneading the materials (negative electrode active material, binder, etc.) of the negative electrode composite material layer 22 and a solvent. The thickness of the negative electrode composite material layer 22 is, for example, 0.1 μm or more and 1000 μm or less.

[0051] As Figure 6 shown, 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 coated with the negative electrode composite material layer 22. In other words, the negative electrode coated portion 21a is the portion covered by the negative electrode composite material layer 22 and not exposed. In addition, the negative electrode coated portion 21a and the negative electrode uncoated portion 21b are examples of the "second coated portion" and the "second uncoated portion" of the present disclosure, respectively.

[0052] The negative electrode uncoated portion 21b is the portion of the negative electrode current collector 21 that is exposed without being covered by the negative electrode composite material layer 22 and the insulating portion 25 described later. The negative electrode uncoated portion 21b is located on the Z2 side relative to the negative electrode coated portion 21a. Specifically, the negative electrode uncoated portion 21b protrudes from the negative electrode coated portion 21a toward the Z2 side. In addition, the Z2 side is an example of the "other side in the axial direction" of the present disclosure.

[0053] The negative electrode uncoated portion 21b is bent radially inward by contacting the negative electrode current collector plate 7 disposed on the Z2 side. As a result, the negative electrode current collector plate 7 becomes negatively charged. In addition, the negative electrode uncoated portion 21b and the negative electrode current collector plate 7 are joined by welding.

[0054] The uncoated portion 21b of the negative electrode includes a plurality of sheet portions 21c. The plurality of sheet portions 21c are arranged along the winding direction of the wound electrode body 1. In addition, the sheet portion 21c is an example of the "second sheet portion" of the present disclosure.

[0055] As Figure 7 shown, the positive electrode sheet 10 (positive electrode current collector 11) and the negative electrode sheet 20 (negative electrode current collector 21) are each formed to be long in the winding direction of the wound electrode body 1. In addition, the winding direction of the wound electrode body 1 is the extending direction of the positive electrode sheet 10 (negative electrode sheet 20) in a state where the winding is unwound and expanded ( Figure 7 the X direction).

[0056] The positive electrode sheet 10 includes a long side 13 and a long side 14. The long side 13 is located at the end on the Z1 side of the positive electrode sheet 10. The long side 14 is located at the end on the Z2 side of the positive electrode sheet 10. The uncoated portion 11b (a plurality of sheet portions 11c) of the positive electrode is provided on the long side 13. The plurality of sheet portions 11c are arranged and configured along the X direction. In addition, the long side 13 and the long side 14 are each an example of the "first long side" and the "third long side" of the present disclosure.

[0057] The negative electrode sheet 20 includes a long side 23 and a long side 24. The long side 23 is located at the end on the Z1 side of the negative electrode sheet 20. The long side 24 is located at the end on the Z2 side of the negative electrode sheet 20. The uncoated portion 21b (a plurality of sheet portions 21c) of the negative electrode is provided on the long side 24. The plurality of sheet portions 21c are arranged and configured along the X direction. In addition, the long side 23 and the long side 24 are each an example of the "second long side" and the "fourth long side" of the present disclosure.

[0058] Here, in the configuration of a conventional power storage unit, for example, the plurality of sheet portions in the positive electrode sheet may be bent and come into contact with the negative electrode sheet.

[0059] Therefore, in the present embodiment, the power storage unit 100 includes an insulating portion 25 formed on the long side 23 of the negative electrode sheet 20. The insulating portion 25 is coated with an insulating material on a portion 25a of the negative electrode current collector 21 where the negative electrode composite material layer 22 is not coated (refer to Figure 5 ). The portion 25a is a portion corresponding to the long side 23 and is a portion provided at the end on the Z1 side in the negative electrode current collector 21. In addition, the insulating portion 25 is an example of the "first insulating portion" and the "insulating member" of the present disclosure.

[0060] In addition, the power storage unit 100 includes an insulating portion 15 formed on the long side 14 of the positive electrode sheet 10. The insulating portion 15 is coated with an insulating material on a portion 15a of the positive electrode current collector 11 where the positive electrode composite material layer 12 is not coated (refer to Figure 6 ). The portion 15a is a portion corresponding to the long side 14 and is a portion provided at the end on the Z2 side in the positive electrode current collector 11. In addition, the insulating portion 15 is an example of the "second insulating portion" and the "insulating member" of the present disclosure.

[0061] As Figure 5 shown, the insulating portion 25 covers the portion 25a so as to avoid exposure of the portion 25a. Specifically, the insulating portion 25 is formed so as to cover the portion 25a from both sides in the radial direction and the Z1 side. Thus, the non-coated portion 11b (sheet portion 11c) of the positive electrode and the portion 25a are reliably insulated.

[0062] In addition, as described above, the insulating portion 25 is coated on the portion 25a of the negative electrode current collector 21 where the negative electrode composite material layer 22 is not coated. Thus, the generation of a step at the boundary between the portion 25a coated with the insulating portion 25 and the portion (21a) coated with the negative electrode composite material layer 22 is suppressed. As a result, stress applied to the negative electrode sheet 20 during expansion and contraction of the wound electrode body 1 can be suppressed.

[0063] As Figure 6 shown, the insulating portion 15 covers the portion 15a so as to avoid exposure of the portion 15a. Specifically, the insulating portion 15 is formed so as to cover the portion 15a from both sides in the radial direction and the Z2 side. Thus, the non-coated portion 21b (sheet portion 21c) of the negative electrode and the portion 15a are insulated.

[0064] In addition, as described above, the insulating portion 15 is coated on the portion 15a of the positive electrode current collector 11 where the positive electrode composite material layer 12 is not coated. Thus, the generation of a step at the boundary between the portion 15a coated with the insulating portion 15 and the portion (11a) coated with the positive electrode composite material layer 12 is suppressed. As a result, stress applied to the positive electrode sheet 10 during expansion and contraction of the wound electrode body 1 can be suppressed.

[0065] As Figure 7 shown, the insulating portion 15 is continuously formed in the X direction. That is, the insulating portion 15 is constituted by a single member extending in the X direction. Similarly, the insulating portion 25 is continuously formed in the X direction. That is, the insulating portion 25 is constituted by a single member extending in the X direction.

[0066] Specifically, the insulating portion 15 is formed so as to extend from the end portion 11d (for example, the winding start portion) on the X1 side of the positive electrode sheet 10 to the end portion 11e (winding end portion) on the X2 side of the positive electrode sheet 10. The insulating portion 25 is formed so as to extend from the end portion 21d (winding start portion) on the X1 side of the negative electrode sheet 20 to the end portion 21e (winding end portion) on the X2 side of the negative electrode sheet 20.

[0067] In addition, in the present embodiment, the insulating portion 15 and the insulating portion 25 are each formed of a porous material. Specifically, the insulating portion 15 and the insulating portion 25 are each formed of alumina. In Figure 7 order to indicate that the insulating portion 15 and the insulating portion 25 are each a porous material, the air holes 16 contained in the alumina are represented by dots.

[0068] Accordingly, the insulating portion 15 and the insulating portion 25 can each allow gas and liquid to pass through. As a result, it is possible to suppress the injection of the electrolytic solution from being obstructed by the insulating portion 15 and the insulating portion 25 respectively.

[0069] In addition, since alumina has heat resistance, it is possible to suppress heat from being applied to the separator and the like through the insulating portion 15 and the insulating portion 25 respectively. Therefore, when welding the sheet portion 11c to the positive current collector plate 4 and when welding the sheet portion 21c to the negative current collector plate 7, etc., it is possible to suppress heat from being applied to the separator and the like.

[0070] As described above, in the present embodiment, the insulating portion 25 is formed on the long side 23 of the negative electrode sheet 20. Thus, through the insulating portion 25, it is possible to electrically isolate the uncoated portion 11b (sheet portion 11c) of the positive electrode of the positive electrode sheet 10 and the long side 23 of the negative electrode sheet 20. As a result, it is possible to prevent the positive electrode sheet 10 and the negative electrode sheet 20 from conducting.

[0071] Figure 8 It is a diagram showing a modification of the above-described embodiment. As Figure 8 shown, the positive electrode sheet 110 includes a positive current collector 111, a long side 113, and a long side 114. The long side 113 is located at the end on the Z1 side of the positive electrode sheet 110. The long side 114 is located at the end on the Z2 side of the positive electrode sheet 110. A plurality of sheet portions 11c are provided on the long side 113. The insulating portion 115 ( Figure 8 the diagonal portion) is formed on the long side 114. In addition, the positive electrode sheet 110 and the positive current collector 111 are each an example of the "first electrode sheet" and the "first current collector" of the present disclosure. In addition, the long side 113 and the long side 114 are each an example of the "first long side" and the "second long side" of the present disclosure. In addition, the insulating portion 115 is an example of the "second insulating portion" and the "insulating member" of the present disclosure.

[0072] The insulating portion 115 is formed intermittently along the X direction. The distance D1 between the insulating portions 115 becomes larger toward the X2 side (winding end side). In addition, the width W1 of the insulating portion 115 in the X direction becomes larger toward the X2 side (winding end side). Thus, in a state where the positive electrode sheet 110 is wound, layers with the insulating portion 115 formed and layers without the insulating portion 115 formed are alternately arranged. In addition, the width W1 and the distance D1 may also be constant regardless of the position of the insulating portion 115 in the X direction.

[0073] The negative electrode sheet 120 includes a negative current collector 121, a long side 123, and a long side 124. The long side 123 is located at the end on the Z1 side of the negative electrode sheet 120. The long side 124 is located at the end on the Z2 side of the negative electrode sheet 120. A plurality of sheet portions 21c are provided on the long side 124. The insulating portion 125 ( Figure 8The diagonal portion) is formed on the long side 123. In addition, the negative electrode sheet 120 and the negative electrode current collector 121 are examples of the "second electrode sheet" and the "second current collector" of the present disclosure, respectively. In addition, the long side 123 and the long side 124 are examples of the "first long side" and the "second long side" of the present disclosure, respectively. In addition, the insulating portion 125 is an example of the "first insulating portion" and the "insulating member" of the present disclosure.

[0074] The insulating portions 125 are formed intermittently along the X direction. The distance D2 between the insulating portions 125 becomes larger toward the X2 side (the winding end side). In addition, the width W2 of the insulating portion 125 in the X direction becomes larger toward the X2 side (the winding end side). Thus, in a state where the negative electrode sheet 120 is wound, layers with the insulating portion 125 formed and layers without the insulating portion 125 formed are alternately arranged. In addition, the width W2 and the distance D2 may also be constant regardless of the position of the insulating portion 125 in the X direction.

[0075] In addition, the insulating portion 115 and the insulating portion 125 may not be formed of a porous material as in the above-described embodiment. For example, the insulating portion 115 may be formed of polypropylene. In addition, the insulating portion 125 may be formed of polyethylene, for example. In addition, the insulating portion 115 and the insulating portion 125 may also be formed of a porous material. In addition, it may be that one of the insulating portion on the positive electrode side and the insulating portion on the negative electrode side is formed continuously in the X direction, and the other of the insulating portion on the positive electrode side and the insulating portion on the negative electrode side is formed intermittently in the X direction.

[0076] In the above-described embodiment, an example in which the insulating portions are formed on the positive electrode sheet 10 and the negative electrode sheet 20, respectively, is illustrated, but the present disclosure is not limited thereto. The insulating portion may be formed on only one of the positive electrode sheet 10 and the negative electrode sheet 20.

[0077] It should be considered that the embodiments disclosed this time are illustrative in all aspects and not restrictive. The scope of the present disclosure is represented not by the description of the above-described embodiments but by the claims, and is intended to include all modifications within the meaning and scope equivalent to the claims.

Claims

1. A power storage unit, characterized in that: have: A wound electrode body comprising a first electrode sheet, a second electrode sheet, and a separator disposed between the first electrode sheet and the second electrode sheet; and Insulating member, The first electrode sheet and the second electrode sheet are each formed to be long in the winding direction of the wound electrode body. The first electrode sheet includes a first long side located at an end portion on one side in an axial direction in which a winding axis of the wound electrode body extends. The second electrode sheet includes a second long side located at the end portion of the one side in the axial direction, The first electrode sheet comprises: a first electrode material layer; and The first current collector includes a first coated portion on which the first electrode material layer is formed and a first uncoated portion on which the first electrode material layer is not coated. The first uncoated portion is formed on the first long side and includes a plurality of first sheet portions arranged in the winding direction. The insulating member includes a first insulating portion formed on the second long side.

2. The power storage unit according to claim 1, characterized in that: The first electrode sheet includes a third long side located at an end portion on the other side in the axial direction, The second electrode sheet includes a fourth long side located at the end portion on the other side in the axial direction, The second electrode sheet comprises: a second electrode material layer; and The second current collector includes a second coated portion on which the second electrode material layer is formed and a second uncoated portion on which the second electrode material layer is not coated. The second uncoated portion is formed on the fourth long side and includes a plurality of second sheet portions arranged in the winding direction. The insulating member includes a second insulating portion formed on the third long side.

3. The power storage unit according to claim 1 or 2, characterized in that: The insulating member is formed of a porous material.

4. The power storage unit according to claim 3, characterized in that: The insulating member is continuously formed along the winding direction.

5. The power storage unit according to claim 1 or 2, characterized in that: The insulating member is formed intermittently along the winding direction.

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