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] US Patent Application Publication No. 2016 / 0104875 discloses a battery cell including an electrode body in which electrode sheets (positive electrode sheets and negative electrode sheets) are spirally wound. The electrode sheets are wound in a state where the positive electrode sheets and the negative electrode sheets overlap with each other via a separator. Summary of the invention

[0003] Here, although it is not specified in the above-mentioned U.S. Patent Application Publication No. 2016 / 0104875, sometimes a plurality of sheets (metal sheets) are provided at the axial end of the electrode sheet. For example, sometimes a plurality of sheets of the positive electrode sheet (first electrode sheet) are bent, causing the plurality of sheets to contact the negative electrode sheet (second electrode sheet).

[0004] The present disclosure has been made to solve the above-mentioned problems, and an object of the present disclosure is to provide a power storage unit capable of preventing a plurality of sheet portions provided at an axial end portion of a first electrode sheet from contacting a second electrode sheet.

[0005] An aspect of the present disclosure relates to a storage unit comprising: 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 in a long dimension in the winding direction of the wound electrode body. The first electrode sheet includes a first long side at an end portion located on one side in the axial direction in which the winding axis of the wound electrode body extends. The second electrode sheet includes a second long side at an end portion located on one side in the axial direction. The first electrode sheet includes: a first electrode material layer; and a first current collector including a first coated portion formed with the first electrode material layer and a first uncoated portion not coated with the first electrode material layer. 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.

[0006] In a storage cell according to one aspect of the present disclosure, as described above, a plurality of sheet portions are provided on a first long side at an end portion on one axial side of a first electrode sheet, and a first insulating portion is formed on a second long side at an end portion on one axial side of a second electrode sheet. Thus, even if a plurality of first sheet portions are bent toward the second electrode sheet, the first insulating portion can prevent the plurality of first sheet portions from contacting (conducting) with the second electrode sheet.

[0007] In the storage battery unit involved in one aspect above, preferably, the first electrode sheet includes a third long side located at the 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 includes: a second electrode material layer; and a second current collector, including a second coated portion formed with the second electrode material layer and a second uncoated portion not coated with the second electrode material layer. 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 so configured, even if the plurality of second sheet portions are bent toward the first electrode sheet side, the second insulating portion can prevent the plurality of second sheet portions from contacting (conducting) with the first electrode sheet.

[0008] In the power storage unit according to the above aspect, the insulating member is preferably formed of a porous material. With this structure, 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, it is preferable that the insulating member is continuously formed along the winding direction. With such a configuration, it is possible to more reliably suppress contact between the electrode sheet and the sheet portion.

[0010] In the storage battery cell according to one aspect, the insulating member is preferably formed intermittently along the winding direction. If so, gaps are formed between the insulating members, so that when the electrolyte is injected into the wound electrode body from one side in the axial direction, it is easy to prevent the electrolyte from being blocked by the insulating member.

[0011] According to the present disclosure, it is possible to suppress the plurality of sheet portions provided at the axial end portion of the first electrode sheet from coming into contact with the second electrode sheet. BRIEF DESCRIPTION OF THE DRAWINGS

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

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

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

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

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

[0017] Figure 5 yes Figure 1 A partial enlarged view of the vicinity of the positive electrode collector plate.

[0018] Figure 6 yes Figure 1 A partial enlarged view of the vicinity of the negative electrode collector plate.

[0019] Figure 7 The diagram shows the structure of the positive electrode sheet and the negative electrode sheet in an unwound state according to one embodiment.

[0020] Figure 8 This is a diagram showing a configuration in which the positive electrode sheet and the negative electrode sheet according to a modification of one embodiment are each unwound. DETAILED DESCRIPTION

[0021] Hereinafter, with reference to the attached drawings, the embodiments of the present disclosure will be described. Figure 1 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 electricity storage cell 100 includes 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 , a polymer ring 8 , and a sealing plug 9 .

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

[0024] The outer shell 2 includes a top plate portion 2a, a peripheral wall portion 2c and a sealing plate 2d. The peripheral wall portion 2c is arranged 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 of the Z1 side of the peripheral wall portion 2c. The top plate portion 2a and the peripheral wall portion 2c are formed integrally. The sealing plate 2d is connected to the end of 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 is tightened (chiselled) to the outer peripheral edge of the sealing plate 2d is formed at the end of the Z2 side of the peripheral wall portion 2c. The tightening portion 2e is formed in a circular ring 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 (e.g., lithium ions) to flow between the positive electrode sheet 10 (positive electrode active material) and the negative electrode sheet 20 (negative electrode active material) and separates the positive electrode sheet 10 from the negative electrode sheet 20. The wound electrode body 1 is composed of an electrode plate group obtained by winding the positive electrode sheet 10 and the negative electrode sheet 20 with the separator 30 interposed 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] like Figure 2 As shown, the wound electrode body 1 is wound so that the positive electrode sheet 10, the negative electrode sheet 20, and the separator 30 surround the periphery of the winding axis α. Figure 2 In order to facilitate understanding of the wound state of the wound electrode body 1 , the wound state of the wound electrode body 1 is shown in the figure in which the winding is slightly loosened.

[0027] Refer again Figure 1 The positive terminal 3 includes a disk portion 3a and a rivet portion 3b. The disk portion 3a is exposed by being arranged outside the housing 2. The rivet portion 3b is connected to the disk portion 3a. The rivet portion 3b is arranged in a manner extending from the center of the disk portion 3a to the Z2 side. In addition, the positive terminal 3 is formed of aluminum.

[0028] The plate portion 3a is disposed on the top plate 2a of the housing 2. The top plate portion 2a is provided at the end portion on the Z1 side of the housing 2. The top plate 2a is provided in a manner perpendicular to the Z direction. A through hole 2b (see Figure 5 ). The caulking portion 3b extends from the disk portion 3a disposed outside the housing 2 through the through hole 2b to the inside of the housing 2. In addition, the Z direction is an example of the "axial direction" in the present disclosure.

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

[0030] The external gasket 5 is provided outside the outer case 2. Specifically, the external gasket 5 is arranged between the disk portion 3a of the positive electrode terminal 3 and the top plate portion 2a of the outer case 2. Thus, the positive electrode terminal 3 and the outer case 2 are insulated.

[0031] The internal gasket 6 is provided inside the outer case 2. Specifically, the internal gasket 6 is disposed between the outer case 2 and the positive electrode collector plate 4. Thus, the outer case 2 and the positive electrode collector plate 4 are insulated. In addition, the rivet portion 3b penetrates the internal gasket 6 and contacts the positive electrode collector plate 4.

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

[0033] The polymer ring 8 is provided between the outer peripheral edge of the sealing plate 2d and the constricted portion 2e formed on the peripheral wall portion 2c. The polymer ring 8 has a circular ring shape.

[0034] The sealing plug 9 closes 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 4 is a plan view of the positive electrode current collector plate 4. The positive electrode current collector plate 4 has a disk shape and includes a central portion 4a, spokes 4b, an outer peripheral edge portion 4c, and a piece portion 4d.

[0036] The center portion 4a is provided at the center of the positive electrode current collector plate 4. The rivet portion 3b is joined to the center portion 4a. The spokes 4b are provided so as to extend radially outward from the center portion 4a. Six spokes 4b are provided at equal angular intervals around the center 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. Six spokes 4b connect the outer peripheral edge portion 4c and the central portion 4a, respectively. The spokes 4b are formed so as to bend in the Z direction. In addition, the central portion 4a of the positive electrode current collector plate 4 moves (displaces) the most 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. A sheet 4d is provided inside each of the six through holes 4e. The six sheets 4d are connected to the outer peripheral edge 4c via connecting portions 4f. In addition, the six sheets 4d have a shape that tapers toward the inner side in the radial direction.

[0039] Figure 4 2 is a plan view of the negative electrode current collector plate 7. The negative electrode current collector plate 7 has a disk shape and includes a central portion 7a, spokes 7b, an outer peripheral edge portion 7c, and a piece portion 7d.

[0040] The center 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 center portion 7a. Six spokes 7b are provided at equal angular intervals around the center portion 7a of the negative electrode current collector plate 7.

[0041] The outer peripheral edge portion 7c is provided at the outer peripheral edge of the negative electrode current collector plate 7. Six spokes 7b connect the outer peripheral edge portion 7c and the central portion 7a, respectively. Each spoke 7b is formed so as to bend in the Z direction. The outer peripheral edge portion 7c of the negative electrode current collector plate 7 moves (displaces) the most 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. The sheet portions 7d are provided at positions corresponding to the six through holes 7e. Specifically, the six sheet portions 7d are respectively arranged on the inner sides of the corresponding through holes 7e. The six sheet portions 7d are respectively connected to the central portion 7a via connecting portions 7f. In addition, the six sheet portions 7d have a shape that tapers at the top as they go radially inward.

[0043] like Figure 5 As shown, the positive electrode sheet 10 includes a positive electrode collector 11 and a positive electrode composite material layer 12. The positive electrode composite material layer 12 is coated on both radial (R direction) surfaces of the positive electrode collector 11 (a 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 collector 11 and the positive electrode composite material layer 12 are examples of the "first current collector" and the "first electrode material layer", respectively.

[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 applying a positive electrode slurry to the surface of the positive electrode current collector 11 and drying it. The positive electrode slurry is a slurry 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 closely attached to 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 a 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 a portion that is covered by the positive electrode composite material layer 12 and is not exposed. In addition, the positive electrode coating portion 11a and the positive electrode uncoated portion 11b are examples of the "first coating portion" and the "first uncoated portion" of the present disclosure, respectively.

[0046] The positive electrode uncoated portion 11b is a 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 closer to the Z1 side than the positive electrode coated portion 11a. Specifically, the positive electrode uncoated portion 11b protrudes from the positive electrode coated portion 11a to the Z1 side. In addition, the Z1 side is an example of "one side in the axial direction" of the present disclosure.

[0047] The positive electrode uncoated portion 11b 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 is positively charged. The positive electrode uncoated portion 11b and the positive electrode current collector plate 4 are joined by welding.

[0048] The positive electrode uncoated portion 11b 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. The sheet portions 11c are an example of the "first sheet portion" in 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) surfaces of the negative electrode current collector 21 (negative electrode coating 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 applying a negative electrode slurry to the surface of the negative electrode current collector 21 and drying it. The negative electrode slurry is a slurry 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] like Figure 6 As shown, the negative electrode current collector 21 includes a negative electrode coating portion 21a and a negative electrode uncoated portion 21b. The negative electrode coating portion 21a is a portion of the negative electrode current collector 21 coated with the negative electrode composite material layer 22. In other words, the negative electrode coating portion 21a is a portion that is covered by the negative electrode composite material layer 22 and is not exposed. In addition, the negative electrode coating portion 21a and the negative electrode uncoated portion 21b are examples of the "second coating portion" and the "second uncoated portion" of the present disclosure, respectively.

[0052] The negative electrode uncoated portion 21b is a portion of the negative electrode current collector 21 that is not covered by the negative electrode composite material layer 22 and the insulating portion 25 described later and is exposed. The negative electrode uncoated portion 21b is located closer to the Z2 side than the negative electrode coated portion 21a. Specifically, the negative electrode uncoated portion 21b protrudes from the negative electrode coated portion 21a to the Z2 side. In addition, the Z2 side is an example of the "other axial side" of the present disclosure.

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

[0054] The negative electrode uncoated portion 21b 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. The sheet portion 21c is an example of a "second sheet portion" in the present disclosure.

[0055] like Figure 7 As shown in FIG. 1 , the positive electrode sheet 10 (positive electrode collector 11) and the negative electrode sheet 20 (negative electrode collector 21) are each formed to be long in the winding direction of the wound electrode body 1. The winding direction of the wound electrode body 1 is the extending direction of the positive electrode sheet 10 (negative electrode sheet 20) in the state where the winding is unwound and expanded ( Figure 7 in 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 of the positive electrode sheet 10 on the Z1 side. The long side 14 is located at the end of the positive electrode sheet 10 on the Z2 side. The positive electrode uncoated portion 11b (a plurality of sheet portions 11c) is provided on the long side 13. The plurality of sheet portions 11c are arranged along the X direction. In addition, the long side 13 and the long side 14 are examples of the "first long side" and the "third long side" of the present disclosure, respectively.

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

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

[0059] Therefore, in this embodiment, the storage cell 100 includes an insulating portion 25 formed on the long side 23 of the negative electrode sheet 20. The insulating portion 25 is formed on a portion 25a of the negative electrode current collector 21 not coated with the negative electrode mixture layer 22 (see Figure 5 ) is coated with an insulating material. The portion 25a is a portion corresponding to the long side 23, and is a portion provided at the end portion on the Z1 side of 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] The storage cell 100 also includes an insulating portion 15 formed on the long side 14 of the positive electrode sheet 10. The insulating portion 15 is formed on a portion 15a of the positive electrode current collector 11 not coated with the positive electrode mixture layer 12 (see Figure 6 ) is coated with an insulating material. The portion 15a is a portion corresponding to the long side 14, and is a portion provided at the end portion on the Z2 side of the positive electrode current collector 11. In addition, the insulating portion 15 is an example of the "second insulating portion" and the "insulating member" disclosed in the present invention.

[0061] like Figure 5 As shown, the insulating portion 25 covers the portion 25a so as to prevent the portion 25a from being exposed. Specifically, the insulating portion 25 is formed so as to cover the portion 25a from both radial sides and the Z1 side. Thus, the positive electrode uncoated portion 11b (sheet portion 11c) and the portion 25a are reliably insulated.

[0062] In addition, as described above, the insulating portion 25 is applied to the portion 25a of the negative electrode current collector 21 that is not coated with the negative electrode composite material layer 22. This prevents 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. As a result, it is possible to prevent stress from being applied to the negative electrode sheet 20 when the wound electrode body 1 expands and contracts.

[0063] like Figure 6 As shown, the insulating portion 15 covers the portion 15a in a manner that prevents the portion 15a from being exposed. Specifically, the insulating portion 15 is formed so as to cover the portion 15a from both radial sides and the Z2 side. Thus, the negative electrode uncoated portion 21b (sheet portion 21c) and the portion 15a are insulated.

[0064] In addition, as described above, the insulating portion 15 is applied to the portion 15a of the positive electrode current collector 11 that is not coated with the positive electrode composite material layer 12. This prevents 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. As a result, it is possible to prevent stress from being applied to the positive electrode sheet 10 when the wound electrode body 1 expands and contracts.

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

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

[0067] In addition, in this 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 aluminum oxide. Figure 7 In FIG. 1 , in order to indicate that the insulating portion 15 and the insulating portion 25 are respectively porous materials, the pores 16 contained in the alumina are indicated by dots.

[0068] Thus, the insulating portion 15 and the insulating portion 25 can allow gas and liquid to pass through each other. As a result, it is possible to suppress the injection of the electrolyte from being hindered by the insulating portion 15 and the insulating portion 25 .

[0069] In addition, since alumina is heat resistant, heat can be suppressed from being applied to the separators etc. by the insulating portions 15 and 25. Therefore, heat can be suppressed from being applied to the separators etc. when welding the sheet portion 11c to the positive electrode collector plate 4 and the sheet portion 21c to the negative electrode collector plate 7.

[0070] As described above, in this embodiment, the insulating portion 25 is formed on the long side 23 of the negative electrode sheet 20. Thus, the positive electrode uncoated portion 11b (sheet portion 11c) of the positive electrode sheet 10 and the long side 23 of the negative electrode sheet 20 can be electrically isolated by the insulating portion 25. As a result, the positive electrode sheet 10 and the negative electrode sheet 20 can be prevented from being electrically connected.

[0071] Figure 8 FIG. 2 is a diagram showing a modified example of the above-mentioned embodiment. Figure 8 As shown, the positive electrode sheet 110 includes a positive electrode current collector 111, a long side 113 and a long side 114. The long side 113 is located at the end of the positive electrode sheet 110 on the Z1 side. The long side 114 is located at the end of the positive electrode sheet 110 on the Z2 side. A plurality of sheet portions 11c are provided on the long side 113. The insulating portion 115 ( Figure 8 The oblique line portion) is formed on the long side 114. In addition, the positive electrode sheet 110 and the positive electrode collector 111 are examples of the "first electrode sheet" and the "first collector" of the present disclosure, respectively. In addition, the long side 113 and the long side 114 are examples of the "first long side" and the "second long side" of the present disclosure, respectively. 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 increases as they are closer to the X2 side (winding end side). In addition, the width W1 of the insulating portion 115 in the X direction increases as they are closer to the X2 side (winding end side). Thus, when the positive electrode sheet 110 is wound, the layers formed with the insulating portion 115 and the layers not formed with the insulating portion 115 are alternately arranged. In addition, the width W1 and the distance D1 may be constant regardless of the position of the insulating portion 115 in the X direction.

[0073] The negative electrode sheet 120 includes a negative electrode current collector 121, a long side 123, and a long side 124. The long side 123 is located at the end of the negative electrode sheet 120 on the Z1 side. The long side 124 is located at the end of the negative electrode sheet 120 on the Z2 side. A plurality of sheet portions 21c are provided on the long side 124. The insulating portion 125 ( Figure 8The oblique line portion) is formed on the long side 123. In addition, the negative electrode sheet 120 and the negative electrode collector 121 are examples of the "second electrode sheet" and the "second 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 portion 125 is formed intermittently along the X direction. The distance D2 between the insulating portions 125 increases as they are closer to the X2 side (winding end side). In addition, the width W2 of the insulating portion 125 in the X direction increases as they are closer to the X2 side (winding end side). Thus, when the negative electrode sheet 120 is wound, the layers formed with the insulating portion 125 and the layers not formed with the insulating portion 125 are alternately arranged. In addition, the width W2 and the distance D2 may 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 be formed of a porous material, respectively, unlike the above-mentioned 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 be formed of a porous material, respectively. In addition, one of the insulating portion on the positive electrode side and the insulating portion on the negative electrode side may be 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 may be formed intermittently in the X direction.

[0076] In the above embodiment, an example is described in which the insulating portion is formed on each of the positive electrode sheet 10 and the negative electrode sheet 20 , 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] The embodiments disclosed this time should be considered as illustrative in all aspects and not restrictive. The scope of the present disclosure is indicated by the claims rather than the description of the embodiments described above, and is intended to include all modifications within the meaning and scope equivalent to the claims.

Claims

1. A power storage unit comprising: 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, 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, The insulating member is formed of a porous material.

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

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

Images