Electricity storage unit

Abstract

The present disclosure relates to a power storage unit. The purpose of the present disclosure is to increase the infiltration speed of an electrolyte solution. A power storage cell includes a case, an electrode body, an insulating film, and an electrolyte solution. The case accommodates the electrode body, the insulating film, and the electrolyte. The electrode body has an upper surface, a lower surface, and a peripheral surface. A liquid injection hole is formed in the surface, opposite to the upper surface, of the shell. The peripheral surface connects the upper surface and the lower surface. The peripheral surface includes a first region and a second region. The first region is covered with an insulating film. The second region is not covered by the insulating film. The second region extends from the upper surface to the lower surface. The second region has a smaller area than the first region.

Description

Technical Field

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

[0002] Japanese Patent Application Laid-Open No. 2016-100270 discloses an insulating tape bonded to the outermost periphery of an electrode body. Summary of the invention

[0003] The storage unit includes a shell and an electrode body. The shell accommodates the electrode body. After accommodating the electrode body, an electrolyte is injected into the shell. From the perspective of the energy density of the storage unit, it is required to reduce the clearance between the shell and the electrode body. The smaller the clearance, the more likely the flow path of the electrolyte around the electrode body will be reduced. Therefore, there is a tendency that a long time is required for the electrolyte to spread throughout the entire electrode body. That is, there is room for improvement in the penetration rate of the electrolyte.

[0004] An object of the present disclosure is to increase the impregnation rate of the electrolyte.

[0005] The following describes the technical solution and effects of the present disclosure. However, the mechanism of action includes assumptions. The mechanism of action does not limit the technical scope of the present disclosure.

[0006] 1. A storage unit, comprising a shell, an electrode body, an insulating film and an electrolyte. The shell accommodates the electrode body, the insulating film and the electrolyte. The electrode body has an upper surface, a lower surface and a peripheral surface. In the shell, a liquid injection hole is provided on the surface opposite to the upper surface. The peripheral surface connects the upper surface and the lower surface. The peripheral surface includes a first region and a second region. The first region is covered by the insulating film. The second region is not covered by the insulating film. The second region extends from the upper surface to the lower surface. The area of ​​the second region is smaller than that of the first region.

[0007] The electrolyte injected from the injection hole is supplied to the upper surface of the electrode body. Due to the thickness of the insulating film, a gap can be formed between the second region and the shell. The gap becomes a flow path for the electrolyte, and the electrolyte can be quickly supplied from the upper surface to the lower surface. Therefore, it is expected that the impregnation speed will be improved.

[0008] 2. The power storage unit of the above-mentioned "1" may include the following schemes, for example.

[0009] The power storage unit further includes an insulating member. The insulating member is arranged in the case at a position facing the second region.

[0010] The insulating member can electrically insulate the second region from the case.

[0011] 3. The power storage unit of "1" or "2" above may include the following schemes, for example.

[0012] The second area is arranged below the liquid injection hole.

[0013] By arranging the second region below the injection hole, it is expected that the impregnation rate will be improved.

[0014] 4. The power storage unit described in any one of "1" to "3" above may include the following aspects, for example.

[0015] The power storage unit further includes an insulating band. In the circumferential direction of the peripheral surface, the second region is sandwiched by the first region. The insulating band extends across the second region and bridges the first regions.

[0016] The insulating tape can electrically insulate the second region from the housing.

[0017] 5. The power storage unit described in any one of "1" to "4" above may include the following aspects, for example.

[0018] The insulating film is in the shape of a strip.

[0019] The tape-shaped insulating film is suitable for being attached to the peripheral surface. When the insulating film is tape-shaped, for example, an improvement in productivity can be expected.

[0020] 6. The power storage unit described in any one of "1" to "5" above may include the following aspects, for example.

[0021] The insulating film is wound around the circumference.

[0022] 7. The power storage unit described in any one of "1" to "6" above may include the following aspects, for example.

[0023] The insulating film has a length direction and a width direction. The width direction is perpendicular to the length direction. The dimension in the length direction is shorter than the circumference of the peripheral surface.

[0024] When the length dimension of the insulating film is shorter than the circumference of the peripheral surface, a gap can be formed between the starting end and the ending end of the insulating film when the insulating film is wound around the peripheral surface. That is, the second region can be formed.

[0025] 8. The power storage unit described in any one of "1" to "7" above may include the following aspects, for example.

[0026] The electrode body has a cubic shape and is a stacked type.

[0027] 9. The power storage unit described in any one of "1" to "8" above may include the following aspects, for example.

[0028] The peripheral surface is composed of a first region and a second region.

[0029] The following describes an embodiment of the present disclosure (hereinafter referred to as "the present embodiment"). However, the present embodiment does not limit the technical scope of the present disclosure. The present embodiment is illustrative in all aspects. The present embodiment is non-restrictive. The technical scope of the present disclosure includes all changes within the meaning and scope equivalent to those described in the claims. For example, it is intended from the outset to include a solution that extracts any solution from the present embodiment and combines them arbitrarily.

[0030] The foregoing and other objects, features, aspects and advantages of the present disclosure will become more apparent from the following detailed description of the present disclosure when read in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a schematic perspective view showing an example of a power storage unit in this embodiment.

[0032] Figure 2 It is a first schematic cross-sectional view showing an example of the power storage unit in the present embodiment.

[0033] Figure 3 This is a schematic diagram showing an example of an electrode body in this embodiment.

[0034] Figure 4 It is a second schematic cross-sectional view showing an example of the power storage unit in the present embodiment.

[0035] Figure 5 This is a schematic cross-sectional view showing an example of the electrode body according to the present embodiment. DETAILED DESCRIPTION

[0036] 1. Explanation of terms

[0037] "Having", "including", "having" and their variations are open-ended terms. In addition to the essential elements, an open-ended term may or may not contain additional elements. The statement "consisting of..." is a closed-ended term. However, even a solution expressed in a closed-ended term may generally contain incidental impurities or additional elements that are not related to the disclosed technology. The statement "consisting essentially of..." is a semi-closed term. In a semi-closed term, it is allowed to add elements that have no substantial effect on the basic and novel characteristics of the disclosed technology.

[0038] Geometric terms should not be understood in a strict sense. Examples of geometric terms include "parallel", "perpendicular", and "orthogonal". For example, "parallel" may slightly deviate from "parallel" in a strict sense. For example, geometric terms may include tolerances, errors, etc. in design, operation, and manufacturing. The dimensional relationships in the drawings are sometimes inconsistent with the actual dimensional relationships. In order to help the reader understand, the dimensional relationships in the drawings are sometimes changed. For example, sometimes the length, width, thickness, etc. are changed. In addition, some structures are sometimes omitted.

[0039] Unless otherwise specified, a numerical range such as "m to n%" includes an upper limit and a lower limit. That is, "m to n%" means a numerical range of "above m% and below n%. In addition, "above m% and below n%" includes "more than m% and less than n%. "Above" and "below" are represented by an inequality "≤" with an equal sign. "Exceeding" and "less than" are represented by an inequality "<" without an equal sign. A value arbitrarily selected from the numerical range may also be used as a new upper limit or lower limit. For example, a new numerical range may be set by arbitrarily combining the numerical values ​​within the numerical range with the numerical values ​​recorded in other parts, tables, figures, etc. in this specification.

[0040] All numerical values ​​are modified by the term "about". The term "about" may represent, for example, ±5%, ±3%, ±1%, etc. All numerical values ​​may be approximate values ​​that may vary according to the utilization form of the technology disclosed herein. All numerical values ​​may be represented by significant figures. Unless otherwise specified, the measured value may be the average value of multiple measurements. The number of measurements may be more than 3, more than 5, or more than 10. It is generally expected that the more the number of measurements, the higher the reliability of the average value. The measured value may be rounded off by rounding off based on the number of significant figures. The measured value may, for example, include errors such as the detection limit of the accompanying measuring device.

[0041] 2. Storage unit

[0042] Figure 1 1 is a schematic perspective view showing an example of a storage unit in this embodiment. The storage unit 1 may have, for example, a height direction, a width direction, and a thickness direction. The height direction, the width direction, and the thickness direction are orthogonal to each other. The "height direction" is Figure 1 The width direction is Figure 1 The thickness direction is Figure 1 The height direction may be parallel to the vertical direction, for example. The width direction and the thickness direction may be parallel to the horizontal direction, for example. "Height" means the dimension in the height direction. "Width" means the dimension in the width direction. "Thickness" means the dimension in the thickness direction or the thickness of the object.

[0043] Figure 2 It is a first schematic cross-sectional view showing an example of the power storage unit in the present embodiment. Figure 2 The cross section perpendicular to the thickness direction is shown. The power storage cell 1 includes a housing 200, an electrode body 100, an insulating film 101, and an electrolyte (not shown). The electrolyte is a liquid electrolyte. The electrolyte may also contain, for example, an organic solvent and a lithium salt.

[0044] 3. Electrode body, insulating film

[0045] The electrode body 100 may have a cubic shape, for example. The electrode body 100 may have a rectangular shape, for example. The electrode body 100 may have a flat rectangular shape, for example.

[0046] "The first aspect ratio" indicates the ratio of the width of the electrode body 100 to the height. The first aspect ratio may be, for example, any one of greater than 1, greater than 1.5, greater than 2, greater than 2.5, greater than 3, greater than 5, and greater than 10. The first aspect ratio may be, for example, any one of less than 10, less than 5, less than 3, less than 2.5, less than 2, and less than 1.5. "The second aspect ratio" indicates the ratio of the thickness of the electrode body 100 to the height. The second aspect ratio may be, for example, any one of greater than 0.1, greater than 0.2, greater than 0.3, greater than 0.5, and greater than 1. The second aspect ratio may be, for example, any one of less than 1, less than 0.5, less than 0.3, and less than 0.2.

[0047] Figure 3 1 is a schematic diagram showing an example of an electrode body in the present embodiment. The electrode body 100 has an upper surface 100a, a lower surface 100b and a peripheral surface 100c. The upper surface 100a, the lower surface 100b and the peripheral surface 100c can be flat surfaces or concave-convex surfaces. The upper surface 100a can also be parallel to the lower surface 100b. The peripheral surface 100c connects the upper surface 100a and the lower surface 100b. The peripheral surface 100c can also include 4 planes. Each plane can also be a rectangle.

[0048] Figure 4 It is a second schematic cross-sectional view showing an example of the power storage unit in the present embodiment. Figure 4 The cross section perpendicular to the height direction is shown. The peripheral surface 100c includes the first region R1 and the second region R2. The peripheral surface 100c may be composed of the first region R1 and the second region R2.

[0049] The first region R1 is covered by the insulating film 101. The insulating film 101 may be attached to the first region R1. The insulating film 101 may be bonded to the first region R1. For example, the insulating film 101 may be bonded to the first region R1 using an adhesive material. The first region R1 may be a continuous region. The first region R1 may be divided into a plurality of parts.

[0050] The second region R2 is not covered by the insulating film 101. The second region R2 may be a continuous region. The second region R2 may also be divided into a plurality of parts. The second region R2 is sandwiched by the first region R1. In the circumferential direction of the peripheral surface 100c, the second region R2 may also be sandwiched by, for example, the beginning of the first region R1 and the end of the first region R1. The second region R2 extends in the height direction. The second region R2 extends from the upper surface 100a to the lower surface 100b.

[0051] The area of ​​the second region R2 is smaller than that of the first region R1. The ratio of the area of ​​the second region R2 to the area of ​​the first region R1 may be, for example, any one of 0.5 or less, 0.4 or less, 0.3 or less, 0.2 or less, 0.1 or less, 0.05 or less, 0.03 or less, and 0.01 or less. The ratio of the area of ​​the second region R2 to the area of ​​the first region R1 may be, for example, any one of 0.001 or more, 0.005 or more, 0.01 or more, 0.05 or more, and 0.1 or more.

[0052] In addition, when the first region R1 is divided into a plurality of parts, the total area of ​​all the parts is regarded as the area of ​​the first region R1. The same applies to the second region R2.

[0053] The insulating film 101 has a length direction and a width direction. The width direction is orthogonal to the length direction. The width direction of the insulating film 101 is parallel to the height direction. The insulating film 101 may be, for example, in a strip shape. The length direction of the insulating film 101 may also be shorter than the circumference of the peripheral surface 100c. By winding the insulating film 101 shorter than the circumference around the peripheral surface 100c, a continuous first region R1 can be formed.

[0054] The thickness of the insulating film 101 may be, for example, any one of 1 μm or more, 5 μm or more, 10 μm or more, 50 μm or more, 100 μm or more, 500 μm or more, and 1 mm or more. The thickness of the insulating film 101 may be, for example, any one of 2 mm or less, 1 mm or less, 500 μm or less, 100 μm or less, 50 μm or less, 10 μm or less, and 5 μm or less. The thickness of the insulating film 101 may be uniform or may be partially different. A single insulating film 101 may be used. A plurality of insulating films 101 may also be used. For example, a plurality of insulating films 101 may be stacked. For example, a plurality of insulating films 101 may also be spliced.

[0055] The insulating film 101 has electrical insulation. The insulating film 101 may include any material as long as it has electrical insulation. The insulating film 101 may be made of, for example, resin. The insulating film 101 may include, for example, at least one selected from polypropylene (PP), polyimide (PI), polyethylene (PE), polyethylene terephthalate (PET), and polyphenylene sulfide (PPS).

[0056] The power storage unit 1 may further include a first insulating member 102. The area of ​​the first insulating member 102 may be larger than that of the second region R2. The ratio of the area of ​​the first insulating member 102 to the area of ​​the second region R2 may be, for example, any one of 1.01 or more, 1.1 or more, 1.2 or more, 1.5 or more, and 2 or more. The ratio of the area of ​​the first insulating member 102 to the area of ​​the second region R2 may be, for example, any one of 2.5 or less, 2.0 or less, and 1.5 or less.

[0057] The first insulating member 102 may be disposed on the surface of the housing 200, for example. For example, the first insulating member 102 may be disposed at a position opposite to the second region R2 in the housing 200. The first insulating member 102 may include, for example, an insulating paint or the like. For example, an insulating paint may be applied at a position opposite to the second region R2 in the housing 200. The insulating paint may include, for example, ceramic powder, resin powder, resin film, or the like.

[0058] The first insulating member 102 may also include, for example, an insulating tape, etc. The insulating tape may extend, for example, across the second region R2 and bridge the first regions R1. The insulating tape may extend, for example, to connect the beginning of the first region R1 and the end of the first region R1. The insulating tape may be attached to the insulating film 101 or to the housing 200. The insulating tape may be thinner than the insulating film 101, for example. The ratio of the thickness of the insulating tape to the thickness of the insulating film 101 may be, for example, any one of less than 1, less than 0.9, less than 0.8, less than 0.7, less than 0.6, and less than 0.5. The ratio of the thickness of the insulating tape to the thickness of the insulating film 101 may be, for example, any one of greater than 0.1, greater than 0.2, greater than 0.3, greater than 0.4, and greater than 0.5.

[0059] The insulating tape may include, for example, a base layer and an adhesive layer. The adhesive layer is laminated on the base layer. The base layer may include, for example, the same material as the insulating film 101. The thickness of the base layer may be, for example, 1 to 100 μm. The adhesive layer may include, for example, at least one selected from an acrylic adhesive, a silicone adhesive, a polyurethane adhesive, and a rubber adhesive.

[0060] 4.Layered structure

[0061] The electrode body may have any stacking structure. For example, the electrode body may be a wound type. For example, the electrode body may be a stacking type.

[0062] Figure 5 This is a schematic cross-sectional view showing an example of the electrode body according to the present embodiment. Figure 5 The electrode body 100 is of a stacked type. The electrode body 100 includes one or more first electrodes 110, one or more second electrodes 120, and one or more separators 130. In the thickness direction, the first electrodes 110 and the second electrodes 120 are alternately stacked. That is, the thickness direction of the storage cell 1 is parallel to the stacking direction of the first electrode 110 and the second electrode 120. The number of the first electrode 110 and the second electrode 120 may be any one of more than 2, more than 5, more than 10, more than 50, and more than 100, respectively. The number of the first electrode 110 and the second electrode 120 may be any one of less than 200, less than 100, less than 50, less than 10, and less than 5, respectively.

[0063] The polarity of the second electrode 120 is different from that of the first electrode 110. For example, the first electrode 110 may be a positive electrode and the second electrode 120 may be a negative electrode. For example, the first electrode 110 may be a negative electrode and the second electrode 120 may be a positive electrode.

[0064] For example, the first electrode 110 may also include a first current collector 112 and a first active material layer 114. The first current collector 112 may also include, for example, a metal foil, etc. The metal foil may also include, for example, Al, Cu, Ni, Ti, Fe, etc. The first active material layer 114 is arranged on the surface of the first current collector 112. The first active material layer 114 may be arranged only on one side of the first current collector 112. The first active material layer 114 may also be arranged on both sides of the first current collector 112. The first active material layer 114 includes a positive electrode active material or a negative electrode active material. The positive electrode active material may also include, for example, a lithium nickel composite oxide, etc. The negative electrode active material may also include, for example, graphite, SiO, Si, etc.

[0065] The second electrode 120 may include, for example, a second current collector 122 and a second active material layer 124. The second current collector 122 may include, for example, a metal foil or the like. The second active material layer 124 is disposed on the surface of the second current collector 122. The second active material layer 124 may be disposed only on one side of the second current collector 122. The second active material layer 124 may also be disposed on both sides of the second current collector 122. The second active material layer 124 includes a positive electrode active material or a negative electrode active material. The second active material layer 124 may have the same area as the first active material layer 114, or may have a different area. For example, the area of ​​the second active material layer 124 may be larger than the area of ​​the first active material layer 114. The ratio of the area of ​​the second active material layer 124 to the area of ​​the first active material layer 114 may be, for example, any one of greater than 1.01, greater than 1.05, and greater than 1.1. The ratio of the area of ​​the second active material layer 124 to the area of ​​the first active material layer 114 may be, for example, 1.1 or less, 1.05 or less, or 1.01 or less.

[0066] The separator 130 has electrical insulation properties. The separator 130 is porous. The separator 130 may include, for example, a microporous film made of polyolefin. The thickness of the separator 130 may be, for example, any one of 5 to 50 μm, 5 to 30 μm, and 5 to 15 μm. The separator 130 separates the first electrode 110 from the second electrode 120. For example, there may be two or more separators 130. For example, the separators 130 may be inserted one by one between the first electrode 110 and the second electrode 120.

[0067] For example, the diaphragm 130 may be one piece. For example, the diaphragm 130 may include a hairpin portion 135. In the hairpin portion 135, the diaphragm 130 is folded into a hairpin shape. The hairpin shape may be, for example, a "snake shape" or an "accordion shape".

[0068] The hairpin bend 135 includes a plane portion 131 and a folded portion 132. In the plane portion 131, the diaphragm 130 extends in a planar shape. In the folded portion 132, the diaphragm 130 folds back. The folded portions 132 are arranged at both ends in the height direction. The diaphragm 130 folds back in a manner of alternately clamping the first electrode 110 or the second electrode 120. The plane portion 131 clamps the first electrode 110 or the second electrode 120. For example, the diaphragm 130 may also include a peripheral portion 136. The peripheral portion 136 may also be wound in a manner of surrounding the hairpin bend 135. Furthermore, a hairpin bend may also be formed by folding back the diaphragm 130 at both ends in the width direction.

[0069] 5. Housing

[0070] The shell 200 contains the electrolyte and the electrode body 100. The shell 200 may also be airtight. The shell 200 may be sealed. For example, the shell 200 may also include a tank 210 and a cover 220. The tank 210 has an opening. The opening is open in the height direction. The opening may also be opened vertically upward, for example. The tank 210 may also be made of metal, for example. The tank 210 may also contain Al, etc. For example, the tank 210 may also include a bottom wall 212 and a peripheral wall 214. The bottom wall 212 may also be in the shape of a flat plate, for example. The planar shape of the bottom wall 212 may also be in the shape of a rectangle, for example. The peripheral wall 214 stands up from the bottom wall 212. The peripheral wall 214 may also be in the shape of a four-sided cylinder, for example. The width of the peripheral wall 214 may also be greater than the thickness of the peripheral wall 214. The height of the peripheral wall 214 may also be greater than the thickness of the peripheral wall 214. Furthermore, the "thickness of the peripheral wall 214" here refers to the outer dimensions of the shell 200 in the thickness direction.

[0071] The cover 220 blocks the opening of the tank 210. The cover 220 may be welded to the peripheral wall 214. The cover 220 may be, for example, a flat plate. The cover 220 may be, for example, made of metal. The cover 220 may contain, for example, Al. The cover 220 may also include, for example, a pressure release valve 222 and a sealing member 224.

[0072] The pressure release valve 222 may be disposed near the center of the cover 220, for example. The pressure release valve 222 releases the internal pressure of the housing 200. If the internal pressure becomes greater than a set value, the pressure release valve 222 may open. The sealing member 224 seals the injection hole 221. The electrolyte may be injected from the injection hole 221.

[0073] The inner surface of the cover 220 is opposite to the upper surface 100a of the electrode body 100. That is, in the shell 200, an injection hole 221 is provided on the surface opposite to the upper surface 100a. The injection hole 221 may also have a specific positional relationship with the second region R2. The second region R2 may also be arranged below the injection hole 221. For example, the angle formed by the straight line connecting the second region R2 and the injection hole 221 and the height direction may also be less than 60°. The angle formed may also be, for example, any one of less than 45°, less than 30°, less than 15°, less than 5°, less than 3° and less than 1°. The second region R2 may also be arranged, for example, directly below the injection hole 221. For example, in the width direction, the position of the injection hole 221 may also be consistent with the position of the second region R2.

[0074] A pair of external terminals 300 are fixed to the cover 220. The external terminals 300 are connected to the first electrode 110 or the second electrode 120. The external terminals 300 may be made of metal, for example. The external terminals may also include Al, Cu, Ni, etc. The external terminals 300 may also have a rectangular shape, for example. The external terminals 300 may also be connected to a bus bar (not shown).

[0075] The pair of connecting members 400 connects the electrode tab to the external terminal 300. The electrode tab refers to the first electrode tab 116 or the second electrode tab 126. The two connecting members 400 may have substantially the same structure.

[0076] For example, the connecting member 400 may also include a collector tab 410, a secondary tab 420, and a connecting pin 430. The collector tab 410 includes a side portion 412 and an upper portion 414. The side portion 412 is located on the side of the electrode body 100 in the width direction. The upper portion 414 is located above the electrode body 100. The upper portion 414 extends from the upper end of the side portion 412 to the inner side in the width direction.

[0077] The auxiliary tab 420 connects the plurality of electrode tabs to the collector tab 410 . The auxiliary tab 420 may include a first end 422 and a second end 424 . The first end 422 is connected to the plurality of electrode tabs. The second end 424 is connected to the side portion 412 .

[0078] The connecting pin 430 connects the collector tab 410 and the external terminal 300. The connecting pin 430 connects the upper portion 414 and the external terminal 300. For example, the lower end portion of the connecting pin 430 may be inserted into a through hole provided in the upper portion 414.

[0079] The second insulating member 500 insulates the housing 200 from the connecting member 400. For example, the second insulating member 500 may include a first portion 510, a second portion 520, a third portion 530, and a fourth portion 540.

[0080] The first part 510 is fixed to the upper surface of the cover 220. The first part 510 is arranged between the cover 220 and the external terminal 300. The second part 520 is fixed to the lower surface of the cover 220. The second part 520 is arranged between the cover 220 and the upper part 414. The second part 520 is arranged between the cover 220 and the lower part of the connecting pin 430. The third part 530 is arranged between the connecting pin 430 and the cover 220. The third part 530 is cylindrical. The third part 530 surrounds the connecting pin 430. Through holes are provided in the first part 510, the second part 520 and the third part 530. The connecting pin 430 is inserted into the through hole.

[0081] The fourth part 540 is plate-shaped and fixed to the lower surface of the upper part 414. The fourth part 540 is arranged above the electrode body 100. The fourth part 540 is provided with a through hole below the pressure release valve 222. The fourth part 540 is also provided with a through hole below the injection hole 221.

Claims

1. A power storage unit, It includes a shell, an electrode body, an insulating film and an electrolyte. The housing contains the electrode body, the insulating film, and the electrolyte. The electrode body has an upper surface, a lower surface and a peripheral surface, The housing is provided with a liquid injection hole on a surface opposite to the upper surface. The peripheral surface connects the upper surface and the lower surface, The peripheral surface includes a first area and a second area, The first region is covered by the insulating film, The second region is not covered by the insulating film, The second region extends from the upper surface to the lower surface, and The second region has a smaller area than the first region.

2. The power storage unit according to claim 1, Also includes an insulating member, and The insulating member is arranged in the housing at a position facing the second region.

3. The power storage unit according to claim 1, The second region is disposed below the liquid injection hole.

4. The power storage unit according to claim 1, Also includes insulation tape, In the circumferential direction of the peripheral surface, the second region is sandwiched by the first region, and The insulating tape extends across the second region and bridges the first regions.

5. The power storage unit according to claim 1, The insulating film is in a strip shape.

6. The power storage unit according to claim 1, The insulating film is wound around the peripheral surface.

7. The power storage unit according to claim 1, The insulating film has a length direction and a width direction, The width direction is orthogonal to the length direction, and a dimension in the length direction is shorter than a circumference of the peripheral surface.

8. The power storage unit according to claim 1, The electrode body has a cubic outer shape, and the electrode body is a stacked type. 9 . The power storage unit according to claim 1 , wherein the peripheral surface is composed of the first region and the second region.

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