Energy storage cell

Abstract

To reduce contact resistance between an electrode terminal and a reverse plate.SOLUTION: A storage cell comprises a cell case and an electrode body. The cell case contains the electrode body. The cell case comprises a case body and a lid. The lid comprises a first electrode terminal, an insulation member, a reverse plate, a lid body, and a second electrode terminal. The lid body electrically connects the reverse plate and the second electrode terminal. The insulation member electrically isolates the electrode terminal from the lib body. The reverse plate has a first face. The first electrode terminal has a second face. The first face faces the second face. The first face curves in a direction away from the second face. The storage cell is configured such that when the reverse plate is reversed, an electrical contact is generated between the first face and the second face. At least one of the first face and the second face is formed with a groove group.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present disclosure relates to an energy storage cell. [Background technology]

[0002] Japanese Patent Application Laid-Open Publication No. 2017-174732 (Patent Document 1) discloses a short-circuit device. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2017-174732 A Summary of the Invention [Problem to be solved by the invention]

[0004] A storage cell with a short circuit mechanism has been proposed. The short circuit mechanism includes an inversion plate. The inversion plate is curved to form a concave surface, for example. For example, gas may be generated in the storage cell, causing an increase in internal pressure. The increase in internal pressure may be a sign of some abnormality. When the internal pressure increases, the pressure may push the inversion plate, causing the inversion plate (concave surface) to invert. The inversion of the concave surface may form a convex surface. The inversion plate (convex surface) may come into contact with a part of the electrode terminal (for example, a terminal plate, etc.), causing a short circuit path to be formed. For example, a fuse may be blown by a current flowing through the short circuit path. That is, the function of the storage cell is stopped. However, for example, the contact resistance between a part of the electrode terminal and the convex surface (inversion plate) may be large, so that a desired amount of current may not flow.

[0005] Therefore, an object of the present disclosure is to reduce the contact resistance between the electrode terminal and the reversal plate. [Means for solving the problem]

[0006] 1. The energy storage cell includes a cell case and an electrode body. The cell case houses the electrode body. The cell case includes a case body and a lid. The case body has an opening. The lid closes the opening. The lid includes a first electrode terminal, an insulating member, an inversion plate, a lid body, and a second electrode terminal. The lid body supports the first electrode terminal and the second electrode terminal. The second electrode terminal has a polarity different from that of the first electrode terminal. The lid body electrically connects the inversion plate and the second electrode terminal. The insulating member electrically insulates the first electrode terminal from the lid body. The reversal plate has a first surface. The first electrode terminal has a second surface. The first surface faces the second surface. The first surface is curved in a direction away from the second surface. The energy storage cell is configured such that an electrical contact is formed between the first surface and the second surface by inverting the reversal plate. A group of grooves is formed in at least one of the first surface and the second surface.

[0007] Hereinafter, the state in which the inversion plate is inverted is also referred to as the "inverted state." Since a groove group (a plurality of grooves) is formed on at least one surface of the inversion plate and the first electrode terminal, it is expected that the number of electrical contacts (hereinafter, may be abbreviated as "contacts") between the inversion plate and the first electrode terminal in the inverted state will increase. The increase in contacts is expected to reduce the contact resistance.

[0008] 2. The energy storage cell according to "1" above, wherein a first groove group is formed on the first surface. The first groove group forms a first planar pattern. A second groove group is formed on the second surface. The second groove group forms a second planar pattern. The second planar pattern may be different from the first planar pattern, for example.

[0009] The grooves may form a predetermined planar pattern. When grooves are formed in both the inversion plate and the first electrode terminal, the planar patterns of the inversion plate and the first electrode terminal are different from each other, and therefore an increase in the number of contact points in the inversion state is expected.

[0010] 3. In the storage cell described in "2" above, when the first planar pattern and the second planar pattern are placed in the same plane, the group of grooves forming the first planar pattern may, for example, extend so as to intersect with the group of grooves forming the second planar pattern.

[0011] By intersecting the extending directions of the grooves between the first and second planar patterns, an increase in the number of contact points in the inverted state is expected.

[0012] 4. In the storage cell according to the above item "2" or "3", the first or second planar pattern may include, for example, a radially extending groove group. The first or second planar pattern may include, for example, a ring-shaped extending groove group.

[0013] For example, a combination of a radial pattern and an annular pattern is expected to increase the number of contact points in the inverted state.

[0014] 5. In the storage cell described in "2" above, when the first planar pattern and the second planar pattern are placed in the same plane, the group of grooves forming the first planar pattern may extend, for example, perpendicular to the group of grooves forming the second planar pattern.

[0015] By making the grooves extend in directions perpendicular to each other between the first and second planar patterns, it is expected that the number of contact points in the inverted state will increase.

[0016] Hereinafter, an embodiment of the present disclosure (hereinafter, may be abbreviated as "the present embodiment") will be described. However, the present embodiment does not limit the technical scope of the present disclosure. The present embodiment is illustrative in all respects. The present embodiment is non-restrictive. The technical scope of the present disclosure encompasses all modifications within the meaning and scope equivalent to the description of the claims. For example, it is also intended from the beginning that any configuration may be extracted from the present embodiment and arbitrarily combined. [Brief description of the drawings]

[0017] [Figure 1] FIG. 1 is a schematic perspective view of a storage cell according to the present embodiment. [Diagram 2] FIG. 2 is an exploded perspective view of the electricity storage cell in this embodiment. [Diagram 3] FIG. 3 is a schematic cross-sectional view of the electricity storage cell in this embodiment. [Figure 4] FIG. 4 is a schematic cross-sectional view of the periphery of the reversal plate. [Diagram 5] FIG. 5 is a schematic plan view showing the first example. [Figure 6] FIG. 6 is a schematic plan view showing the second example. [Figure 7] FIG. 7 is a schematic plan view showing the third example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] <Definitions of terms, etc.> The words "comprise," "include," "have," and variations thereof (e.g., "consisting of") are open-ended. The open-ended form may or may not include additional elements in addition to the required elements. The words "consisting of" are closed-ended. However, the closed form does not exclude additional elements that are normally associated with the technology or that are unrelated to the technology disclosed. The words "consisting essentially of..." are semi-closed. The semi-closed form allows for the addition of elements that do not substantially affect the basic and novel characteristics of the technology disclosed.

[0019] For example, "at least one of A and B" includes "A or B" as well as "A and B." "At least one of A and B" can also be written as "A and / or B."

[0020] In this embodiment, geometric terms (e.g., "parallel," "perpendicular," "orthogonal," etc.) should not be interpreted in a strict sense. For example, "parallel" may deviate slightly from the strict meaning of "parallel." Geometric terms may include, for example, tolerances, errors, etc. in design, work, manufacturing, etc. The dimensional relationships in each drawing may not match the actual dimensional relationships. In order to aid the reader's understanding, the dimensional relationships (length, width, thickness, etc.) in each drawing may be changed. Furthermore, some configurations may be omitted. In each drawing, the same or equivalent members may be assigned the same numbers.

[0021] The "second electrode" has a polarity different from that of the "first electrode". In this embodiment, the "negative electrode" is the "first electrode" and the "positive electrode" is the "second electrode". That is, for example, the "negative electrode terminal" can be rephrased as the "first electrode terminal". For example, the "positive electrode terminal" can be rephrased as the "second electrode terminal". The same applies to other terms (for example, "negative electrode tab", etc.). However, the polarity in this embodiment is merely an example. The polarity may be reversed. That is, the negative electrode may be the second electrode and the positive electrode may be the first electrode. Note that when simply written as "electrode", "electrode" may be a general term for the negative electrode and the positive electrode.

[0022] <Energy storage cell> Fig. 1 is a schematic perspective view of a storage cell in this embodiment. Fig. 2 is an exploded perspective view of the storage cell in this embodiment. Fig. 3 is a schematic cross-sectional view of the storage cell in this embodiment.

[0023] The energy storage cell 1 may include, for example, an electrode assembly 100, a cell case 200, an electrode terminal 300, a connecting member 400, and an insulator 500 (see FIG. 3).

[0024] The electrode assembly 100 may include, for example, a plurality of unit electrode bodies 111 and an insulating film 120 (see FIG. 2). The electrode assembly 100 may include, for example, two to four unit electrode bodies 111. Each of the plurality of unit electrode bodies 111 may include a plurality of positive electrode tabs 110P and a plurality of negative electrode tabs 110N. Each of the plurality of unit electrode bodies 111 may have, for example, the same structure. Each of the plurality of unit electrode bodies 111 may have, for example, structures different from each other.

[0025] The unit electrode body 111 may have any structure. The unit electrode body 111 may be, for example, a laminate type. The unit electrode body 111 may be, for example, a wound type. The unit electrode body 111 may include, for example, a positive electrode sheet, a separator, and a negative electrode sheet. The positive electrode sheet, the negative electrode sheet, and the separator may have, for example, a band-like planar shape.

[0026] The positive electrode sheet may include, for example, a metal foil and a positive electrode composite layer. The positive electrode composite layer may be disposed on, for example, the surface of the metal foil. For example, the positive electrode composite layer may be formed by coating the surface of the metal foil with a positive electrode slurry. A non-coated portion may be formed on the upper long side of the metal foil. The positive electrode composite layer is not formed on the non-coated portion. The metal foil is exposed in the non-coated portion. For example, a plurality of positive electrode tabs 110P may be joined to the non-coated portion. The plurality of positive electrode tabs 110P may be arranged at intervals from each other.

[0027] The negative electrode sheet may include, for example, a metal foil and a negative electrode composite layer. The negative electrode composite layer may be disposed on, for example, the surface of the metal foil. For example, the negative electrode composite layer may be formed by coating the surface of the metal foil with a negative electrode slurry. A non-coated portion may be formed on the upper long side of the metal foil. The non-coated portion does not have a negative electrode composite layer formed thereon. The non-coated portion exposes the metal foil. For example, a plurality of negative electrode tabs 110N may be joined to the non-coated portion. The plurality of negative electrode tabs 110N may be disposed at intervals from one another.

[0028] For example, a positive electrode sheet, a separator, and a negative electrode sheet may be stacked to form a laminate. The laminate may be spirally wound to form a unit electrode body 111. After winding, the unit electrode body 111 may be formed into a flat shape. In the unit electrode body 111 (in a wound state), the positive electrode tabs 110P may be arranged in the thickness direction. The negative electrode tabs 110N may be arranged in the thickness direction. The "thickness direction" refers to a direction perpendicular to the paper surface of FIG. 3. The positive electrode tabs 110P and the negative electrode tabs 110N may be arranged at intervals in the width direction. The "width direction" refers to a direction perpendicular to each of the thickness direction and the height direction.

[0029] The insulating film 120 may, for example, cover the peripheral and bottom surfaces of a plurality of unit electrode bodies 111 collectively (see FIG. 2).

[0030] The cell case 200 houses the electrode body 100. The cell case 200 also houses an electrolyte (not shown). The cell case 200 is sealed. The cell case 200 includes a case body 210 and a lid 220 (see FIG. 3).

[0031] The case body 210 has an opening 211 that opens upward (see FIG. 2). The case body 210 may be made of, for example, metal. The case body 210 may include, for example, aluminum (Al) or the like. The case body 210 has a bottom wall 212 and a peripheral wall 214 (see FIG. 3). The bottom wall 212 may be, for example, rectangular and flat. The peripheral wall 214 stands up from the bottom wall 212. The peripheral wall 214 may be, for example, rectangular tubular. The length of the peripheral wall 214 in the width direction may be longer than the length of the peripheral wall 214 in the thickness direction. The length of the peripheral wall 214 in the height direction may be longer than the length of the peripheral wall 214 in the thickness direction.

[0032] The lid 220 closes the opening 211. For example, the lid 220 may be joined to the case body 210 by laser welding. The lid 220 may be, for example, flat. The lid 220 may be made of metal. The lid 220 may include, for example, Al or the like. The lid 220 includes a negative electrode terminal 300N (first electrode terminal), an insulating member 340, a reversal plate 224, a lid body 222, and a positive electrode terminal 300P (second electrode terminal) (see FIG. 3). The lid body 222 may include, for example, a pressure release valve 222a, a liquid injection hole 222b, a sealing member 222c, and a pair of pin insertion holes 222d.

[0033] Short Circuit Mechanism The negative electrode terminal 300N includes a negative electrode terminal plate 330 and a negative electrode connecting pin 420N. The negative electrode terminal plate 330 may be made of, for example, a metal. The negative electrode terminal plate 330 may include, for example, copper (Cu), nickel (Ni), or the like. The insulating member 340 electrically insulates the negative electrode terminal 300N from the lid main body 222. The insulating member 340 may be made of, for example, a resin material.

[0034] FIG. 4 is a schematic cross-sectional view of the periphery of the reversal plate. The reversal plate 224 may have an outer shape such as a dish shape or a bowl shape. The reversal plate 224 may have a thickness of, for example, 0.1 to 1 mm. The reversal plate 224 may be made of, for example, an Al alloy. The reversal plate 224 is joined to the lid body 222. For example, the reversal plate 224 may be welded to the lid body 222. The reversal plate 224 has a first surface F1. The negative electrode terminal plate 330 has a second surface F2. That is, the negative electrode terminal 300N (first electrode terminal) has a second surface F2. The first surface F1 faces the second surface F2. The reversal plate 224 has a cross-sectional shape that is convex downward in the height direction (Z-axis direction). The first surface F1 curves in a direction away from the second surface F2. The first surface F1 may form, for example, a concave surface. The second surface F2 may have any cross-sectional shape. The second surface F2 may be flat or curved. When the internal pressure of the cell case 200 reaches or exceeds the operating pressure, the reversal plate 224 reverses in the height direction. The operating pressure can be set arbitrarily depending on, for example, the size of the energy storage cell 1. The operating pressure can be adjusted, for example, by the material, thickness, etc. of the reversal plate 224.

[0035] By inverting the reversal plate 224, a contact point is formed between the first face F1 and the second face F2. That is, the energy storage cell 1 is configured such that by inverting the reversal plate 224, a contact point is formed between the first face F1 and the second face F2. A short-circuit path is formed through the contact point. That is, the negative electrode terminal plate 330, the reversal plate 224, the lid body 222, and the positive electrode terminal 300P are electrically connected to each other.

[0036] For example, by disposing a fuse in the short-circuit path, the fuse can be blown by a current flowing through the short-circuit path. The fuse can be disposed at any location in the short-circuit path. For example, at least one of the positive electrode current collector 410P and the positive electrode connecting pin 420P may include a fuse. The fuse can have any structure. The fuse can include, for example, a notch portion, a thin portion, etc. The fuse can include any fusible material. The fuse can include, for example, an alloy material, a resin material, etc.

[0037] In Fig. 4, grooves are formed on both the first face F1 and the second face F2. In the inverted state, the grooves are expected to increase the number of contact points. For example, when grooves are present on only one of the first face F1 or the second face F2, an increase in the number of contact points can be expected.

[0038] The grooves may have any planar shape. The planar shape of the grooves may be, for example, linear, dot-like, etc. The grooves may have any cross-sectional shape. The cross-sectional shape of the grooves may be, for example, V-shaped, U-shaped, rectangular, etc. The grooves may have any depth. For example, the depth of the grooves may be 0.1 to 0.9 times, or 0.3 to 0.7 times, the thickness of the reversal plate 224. The groove group includes two or more grooves. The groove group may include, for example, 2 to 100 grooves, 5 to 50 grooves, or 5 to 20 grooves. A plurality of linear grooves may merge with each other. A plurality of dot-like grooves may partially overlap. Linear grooves and dot-like grooves may be mixed.

[0039] In FIG. 4, a first groove group G1 is formed on the first surface F1. A second groove group G2 is formed on the second surface F2. The first groove group G1 forms a first planar pattern. The second groove group G2 forms a second planar pattern. The first planar pattern may be different from the second planar pattern. By making the first planar pattern different from the second planar pattern, an increase in the number of contact points in the inverted state is expected. Each planar pattern may be formed, for example, by at least one of a group of lines and a group of points. Each planar pattern may be regular or irregular.

[0040] (Example 1) FIG. 5 is a schematic plan view showing a first example. The "plane pattern" in this embodiment also includes a pattern in which no grooves are formed. For example, the first plane pattern PT1 may include a groove group extending in a lattice shape. The second plane pattern PT2 may be a flat surface without grooves. The grooves may extend, for example, linearly. The grooves may extend, for example, curvedly. The periphery of each plane pattern may be, for example, circular, elliptical, diamond-shaped, rectangular, etc.

[0041] (Example 2) FIG. 6 is a schematic plan view showing a second example. For example, each of the first plane pattern PT1 and the second plane pattern PT2 may include grooves extending in a line pattern. Line patterns indicate a collection of parallel lines. For example, when the first plane pattern PT1 and the second plane pattern PT2 are placed on the same plane, the grooves forming the first plane pattern PT1 may extend so as to intersect with the grooves forming the second plane pattern PT2. By intersecting the extension directions of the grooves between the first plane pattern PT1 and the second plane pattern PT2, an increase in the number of contact points in the inverted state is expected. The angle between the intersecting grooves may be, for example, 1 to 90 degrees, 10 to 80 degrees, or 30 to 70 degrees. For example, the grooves forming the first plane pattern PT1 may extend so as to be perpendicular to the grooves forming the second plane pattern PT2. By intersecting the extension directions of the grooves between the first plane pattern PT1 and the second plane pattern PT2, an increase in the number of contact points in the inverted state is expected.

[0042] (Example 3) FIG. 7 is a schematic plan view showing a third example. For example, the first plane pattern PT1 may include a group of grooves extending radially. For example, the second plane pattern PT2 may include a group of grooves extending annularly. For example, the second plane pattern PT2 may include a group of grooves extending concentrically. By combining a radial pattern and an annular pattern, an increase in the number of contact points in the inverted state is expected. Each of the first plane pattern PT1 and the second plane pattern PT2 may be, for example, point symmetric or line symmetric.

[0043] (Other flat patterns) For example, in the first to third examples, the first plane pattern PT1 and the second plane pattern PT2 may be interchanged. For example, any plane patterns may be extracted from the first to third examples and arbitrarily combined. One plane pattern may be formed by combining a plurality of types of plane patterns. One plane pattern may be formed by combining a part of any plane pattern with the whole or a part of another plane pattern.

[0044] Other parts The positive electrode terminal 300P includes a positive electrode terminal plate 310, a terminal block 320, and a positive electrode connecting pin 420P (see FIG. 3). The positive electrode terminal plate 310 may have, for example, a rectangular parallelepiped shape. The positive electrode terminal plate 310 may be made of, for example, a metal. The positive electrode terminal plate 310 may include, for example, Al or the like.

[0045] The terminal block 320 may have, for example, a rectangular parallelepiped shape. The terminal block 320 may be made of, for example, a metal. The terminal block 320 may have, for example, a material different from that of the positive terminal plate 310. The terminal block 320 may contain, for example, iron (Fe) or the like. The terminal block 320 is joined to the upper surface of the lid body 222. The positive terminal plate 310 is joined to the upper surface of the terminal block 320. The case body 210 and the lid 220 are electrically connected to the positive terminal plate 310 via the terminal block 320. The case body 210, the lid 220, and the positive terminal plate 310 have the same polarity. A through hole is formed in each of the positive terminal plate 310 and the terminal block 320. The positive connecting pin 420P is inserted into the through hole.

[0046] The connecting member 400 connects the plurality of positive electrode tabs 110P and the electrode terminal 300. The connecting member 400 connects the plurality of negative electrode tabs 110N and the electrode terminal 300. The connecting member 400 includes a current collector 410. The current collector 410 is connected to the plurality of tabs. The current collector 410 includes a positive electrode current collector 410P and a negative electrode current collector 410N.

[0047] The positive electrode current collector 410P is joined to a plurality of positive electrode tabs 110P. The positive electrode current collector 410P includes a first flat plate portion 411 and a second flat plate portion 412.

[0048] A plurality of positive electrode tabs 110P are joined to the first flat plate portion 411. Through holes are formed in the first flat plate portion 411. The plurality of positive electrode tabs 110P are joined to a lower surface of the first flat plate portion 411. However, the plurality of positive electrode tabs 110P may also be joined to an upper surface of the first flat plate portion 411.

[0049] The second flat plate portion 412 is disposed on the outer side of the first flat plate portion 411 in the width direction. A connecting hole 412h is formed in the second flat plate portion 412 (see FIG. 2). A thin portion may be formed between the second flat plate portion 412 and the first flat plate portion 411 (see FIG. 3).

[0050] The negative current collector 410N is joined to a plurality of negative electrode tabs 110N. The negative current collector 410N may have, for example, the same structure as the positive current collector 410P.

[0051] The connecting pins 420 connect the current collecting plate 410 and the electrode terminal 300. The connecting pins 420 include a positive electrode connecting pin 420P and a negative electrode connecting pin 420N.

[0052] The positive electrode connecting pin 420P connects the positive electrode current collector plate 410P and the positive electrode terminal plate 310. The positive electrode connecting pin 420P may have, for example, a cylindrical outer shape. With the positive electrode connecting pin 420P inserted into the connecting hole 412h, the lower end of the positive electrode connecting pin 420P is connected to the second flat plate portion 412. The upper end of the positive electrode connecting pin 420P can be fixed to the positive electrode terminal plate 310 by, for example, crimping.

[0053] The negative electrode connecting pin 420N connects the negative electrode current collector plate 410N and the negative electrode terminal plate 330. The negative electrode connecting pin 420N may have, for example, a cylindrical outer shape. When the negative electrode connecting pin 420N is inserted into the connecting hole 412h, the lower end of the negative electrode connecting pin 420N is connected to the second flat plate portion 412. The upper end of the negative electrode connecting pin 420N can be fixed to the negative electrode terminal plate 330 by, for example, crimping.

[0054] The insulator 500 provides insulation between the connecting member 400 and the cell casing 200. The insulator 500 includes an insulating sheet 510 and an insulating gasket 520.

[0055] The insulating sheet 510 is connected to the lower surface of the lid main body 222. Through holes are formed in the insulating sheet 510 at a portion overlapping the pressure release valve 222a in the height direction, a portion overlapping the liquid injection hole 222b, a portion overlapping each pin insertion hole 222d, and a portion overlapping the reversal plate 224.

[0056] The insulating gasket 520 has a shape that surrounds the connecting pin 420. The insulating gasket 520 provides insulation between the connecting pin 420 and the cell casing 200. The insulating gasket 520 includes a positive electrode gasket 520P and a negative electrode gasket 520N.

[0057] The positive electrode gasket 520P covers the positive electrode connecting pin 420P. The positive electrode gasket 520P has a cylindrical outer shape. The negative electrode gasket 520N covers the negative electrode connecting pin 420N. The negative electrode gasket 520N may have the same structure as the positive electrode gasket 520P. [Explanation of symbols]

[0058] 1 storage cell, 100 electrode body, 110N negative electrode tab, 110P positive electrode tab, 111 unit electrode body, 120 insulating film, 200 cell case, 210 case body, 211 opening, 212 bottom wall, 214 peripheral wall, 220 lid, 222 lid body, 222a pressure release valve, 222b liquid injection hole, 222c sealing member, 222d pin insertion hole, 224 reversal plate, 300 electrode terminal, 300N negative electrode terminal, 300P positive electrode terminal, 310 positive electrode terminal plate, 320 terminal block, 330 negative electrode terminal plate, 340 insulating member, 400 connecting member, 410 current collector, 410N negative electrode current collector, 410P positive electrode current collector, 411 first flat plate portion, 412 Second flat plate portion, 412h connecting hole, 420 connecting pin, 420N negative electrode connecting pin, 420P positive electrode connecting pin, 500 insulator, 510 insulating sheet, 520 insulating gasket, 520N negative electrode gasket, 520P positive electrode gasket, F1 first surface, F2 second surface, G1 first groove group, G2 second groove group, PT1 first plane pattern, PT2 second plane pattern.

Claims

1. A cell case; An electrode body; Including, The cell case accommodates the electrode body, The cell case includes a case body and a lid, The case body has an opening, The lid closes the opening, the lid includes a first electrode terminal, an insulating member, a reversal plate, a lid body, and a second electrode terminal; the lid body supports the first electrode terminal and the second electrode terminal, the second electrode terminal has a polarity different from that of the first electrode terminal, the lid body electrically connects the reversal plate and the second electrode terminal; the insulating member electrically insulates the first electrode terminal from the lid main body, The reversal plate has a first surface, the first electrode terminal has a second surface; The first surface faces the second surface, the first surface is curved in a direction away from the second surface, The reversal plate is configured to be reversed to form an electrical contact between the first surface and the second surface, a group of grooves formed in at least one of the first surface and the second surface; a first group of grooves formed in the first surface; the first groove group forms a first planar pattern, a second group of grooves is formed in the second surface; the second groove group forms a second planar pattern, The second planar pattern is different from the first planar pattern. Energy storage cell.

2. When the first planar pattern and the second planar pattern are placed in the same plane, the groove group forming the first plane pattern extends so as to intersect with the groove group forming the second plane pattern; The storage cell according to claim 1 .

3. the first planar pattern or the second planar pattern includes the grooves extending radially; and the first planar pattern or the second planar pattern includes the groove group extending in an annular shape; The storage cell according to claim 1 or 2.

4. When the first planar pattern and the second planar pattern are placed in the same plane, the groove group forming the first plane pattern extends perpendicular to the groove group forming the second plane pattern; The storage cell according to claim 1 .

Images