Temporary sealing plug, power storage cell, and manufacturing method of power storage cell

Abstract

To provide a temporary sealing plug requiring no put on or take off.SOLUTION: The temporary sealing plug is used for temporarily closing an injection port of a power storage cell after injection. The temporary sealing plug includes a central portion and a periphery portion. In plan view, The periphery portion surrounds the central portion. Radiating cuts are formed from the center portion to the periphery portion.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a temporary sealing plug, an energy storage cell, and a method for manufacturing an energy storage cell. [Background technology]

[0002] JP 2019-145294 A discloses a liquid injection port. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2019-145294 A Summary of the Invention [Problem to be solved by the invention]

[0004] The manufacturing process of the storage cell includes "pouring" and "sealing." That is, the electrolyte is poured into the case through the pouring port. After the electrolyte is poured, the pouring port is closed with a sealing plug. During the period from pouring to sealing, the electrolyte may volatilize from the pouring port. For example, it is possible to temporarily close the pouring port with a temporary sealing plug.

[0005] An initial charge may be performed between injection and sealing. During the initial charge, gas is generated due to decomposition of the electrolyte. In order to keep the internal pressure of the case within a predetermined range, it is desirable to release the gas from the injection port. Therefore, during the initial charge, it is required to remove the temporary sealing plug. If there is a long waiting time before sealing after the initial charge, it is required to close the injection port again with the temporary sealing plug. The work of attaching and detaching the temporary sealing plug may reduce production efficiency.

[0006] To provide a temporary sealing plug that does not need to be attached or detached. [Means for solving the problem]

[0007] 1. In one aspect of the present disclosure, a temporary sealing plug is provided. The temporary sealing plug is used to temporarily close the liquid injection port of the electric storage cell after liquid injection. The temporary sealing plug includes a central portion and a peripheral portion. In a plan view, the peripheral portion surrounds the central portion. Radial cuts are formed from the central portion toward the peripheral portion.

[0008] A temporary sealing plug is attached to the liquid injection port of the case. A nozzle is inserted into the slit of the temporary sealing plug. Electrolyte is injected into the case from the nozzle. The nozzle is pulled out from the temporary sealing plug. The slit can be naturally closed due to the restoring force of the material. The case can be sealed by attaching a sealing plug so as to cover the temporary sealing plug. That is, liquid injection and sealing can be performed without attaching or detaching the temporary sealing plug.

[0009] 2. The temporary sealing plug described in "1" above may include, for example, the following configuration: The temporary sealing plug includes at least one selected from the group consisting of ethylene propylene diene rubber (EPDM), perfluoroalkoxy fluororesin (PFA), and polytetrafluoroethylene (PTFE).

[0010] Rubber and resin materials are expected to exhibit suitable restoring force, while EPDM, PFA, and PTFE are expected to exhibit resistance to electrolytes.

[0011] 3. The temporary sealing plug according to the above item "1" or "2" may have the following configuration, for example: The center portion is raised.

[0012] The raised center portion may be clamped, for example, to reduce volatilization of the electrolyte.

[0013] 4. In one aspect of the present disclosure, a storage cell is provided. The storage cell includes the temporary sealing plug described in any one of "1" to "3" above, a sealing plug, a case, an electrode assembly, and an electrolyte. The case houses the electrode assembly and the electrolyte. The case is provided with a liquid injection port. The sealing plug closes the liquid injection port. The temporary sealing plug is disposed between the liquid injection port and the sealing plug.

[0014] With the temporary sealing plug remaining, sealing can be performed.

[0015] 5. In one aspect of the present disclosure, there is provided a method for producing a storage cell. The method for producing a storage cell includes the following steps (a) to (c): (a) Prepare a case having a filling port. (b) The electrode body is placed in the case. (c) Inject the electrolyte into the case. Furthermore, the above (c) includes the following (c1) to (c4) in this order. (c1) The temporary sealing plug described in any one of the above items "1" to "3" is attached to the liquid injection port. (c2) The nozzle is inserted into the notch of the temporary sealing plug. (c3) The electrolyte is injected from the nozzle. (c4) The nozzle is pulled out from the temporary sealing plug.

[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 includes all modifications within the meaning and scope equivalent to the description of the claims. For example, it is also originally intended that any configuration may be extracted from the present embodiment and arbitrarily combined.

[0017] Geometric terms should not be interpreted in a strict sense. Examples of geometric terms include "parallel," "perpendicular," and the like. For example, "parallel" may deviate slightly from the strict meaning of "parallel." Geometric terms may include, for example, tolerances, errors, and the like in design, work, and manufacturing. The dimensional relationships in each figure may not match the actual dimensional relationships. The dimensional relationships in each figure may be changed to help the reader understand. For example, the length, width, thickness, and the like may be changed. Furthermore, some configurations may be omitted.

[0018] "Planar view" refers to viewing an object with a line of sight parallel to the thickness direction of the object. Planar view is shown in a plan view.

[0019] Unless otherwise specified, the order of execution of the steps, operations, and the like included in various methods is not limited to the order described. For example, the steps may proceed simultaneously. For example, the steps may be performed in sequence. [Brief description of the drawings]

[0020] [Figure 1] FIG. 2 is a schematic plan view showing an example of a temporary sealing plug in the present embodiment. [Diagram 2] 1 is a first schematic cross-sectional view showing an example of a temporary sealing plug in the present embodiment. FIG. [Diagram 3] 4 is a second schematic cross-sectional view showing an example of a temporary sealing plug in the present embodiment. FIG. [Figure 4] 2 is a schematic flowchart of a method for producing a storage cell in the present embodiment. [Diagram 5] 1 is a first schematic diagram illustrating a method for producing a storage cell in the present embodiment. FIG. [Figure 6] 5 is a second schematic diagram illustrating the method for producing a storage cell in the present embodiment. FIG. [Figure 7] 6 is a third schematic diagram illustrating the method for producing a storage cell in the present embodiment. FIG. [Figure 8] 11 is a fourth schematic diagram illustrating the method for producing a storage cell in the present embodiment. FIG. [Figure 9] 1 is a schematic cross-sectional view illustrating an example of a storage cell according to an embodiment of the present invention. [Figure 10] FIG. 2 is a schematic cross-sectional view showing an example of an electrode body in the present embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] 1. Temporary sealing plug FIG. 1 is a schematic plan view showing an example of the temporary sealing plug in this embodiment. FIG. 2 is a first schematic cross-sectional view showing an example of the temporary sealing plug in this embodiment. The outer shape of the temporary sealing plug 10 is arbitrary. The temporary sealing plug 10 may be, for example, a disk shape, an elliptical plate shape, a rectangular plate shape, or the like. The temporary sealing plug 10 may have a structure similar to a chrysanthemum-shaped lid, for example. The temporary sealing plug 10 includes a central portion 12 and a peripheral portion 14. The central portion 12 includes a geometric center of the temporary sealing plug 10. The geometric center of the temporary sealing plug 10 may coincide with the geometric center of the central portion 12. The contour line of the central portion 12 may be circular. The ratio of the maximum diameter of the central portion 12 to the maximum diameter of the temporary sealing plug 10 may be, for example, 0.9 or less, 0.8 or less, 0.7 or less, 0.6 or less, 0.5 or less, 0.4 or less, 0.3 or less, 0.2 or less, or 0.1 or less. The ratio may be, for example, 0.1 or more, 0.2 or more, 0.3 or more, 0.4 or more, 0.5 or more, 0.6 or more, 0.7 or more, 0.8 or more, or 0.9 or more.

[0022] The peripheral portion 14 surrounds the central portion 12. The peripheral portion 14 may be, for example, flange-shaped. The temporary sealing plug 10 has cuts 16 formed therein. The cuts 16 penetrate the temporary sealing plug 10 in the thickness direction. The cuts 16 extend radially from the central portion 12 toward the peripheral portion 14. The multiple cuts 16 may pass through the geometric center. The multiple cuts 16 may intersect at the geometric center.

[0023] 3 is a second schematic cross-sectional view showing an example of the temporary sealing plug in this embodiment. The central portion 12 may be raised in one direction. By raising the central portion 12, for example, the clamp 30 or the like can clamp the central portion 12. By clamping the central portion 12, volatilization of the electrolyte can be reduced.

[0024] The temporary sealing plug 10 is an elastic body. When deformation occurs in the temporary sealing plug 10, a restoring force may be generated. The temporary sealing plug 10 may be resistant to an electrolytic solution. The temporary sealing plug 10 may be made of, for example, rubber or resin. The temporary sealing plug 10 may contain at least one selected from the group consisting of butyl rubber, styrene propylene rubber, EPDM, styrene butadiene rubber, nitrile rubber, fluororubber, natural rubber, PFA, and PTFE.

[0025] 2. Manufacturing method of energy storage cells 4 is a schematic flow chart of a method for producing a storage cell in this embodiment. Hereinafter, the "method for producing a storage cell in this embodiment" may be abbreviated as "this production method". This production method includes "(a) preparation of a case", "(b) storage of an electrode body", and "(c) injection" in this order. This production method may further include "(d) initial charging", "(e) sealing", etc.

[0026] (a) Case preparation 5 is a first schematic diagram showing a method for manufacturing a storage cell in this embodiment. The manufacturing method includes preparing a case 200. The case 200 may include a can 210 and a lid 220. The case 200 has a liquid pouring port 221. For example, the liquid pouring port 221 may be provided in the lid 220.

[0027] (b) Storage of the electrode body This manufacturing method includes housing the electrode body 100 in the case 200. For example, the electrode body 100 is inserted into the can 210 through an opening of the can 210. After the electrode body 100 is inserted, the opening may be closed with a lid 220. For example, the lid 220 may be welded to the can 210 by laser processing.

[0028] (c) Liquid injection This manufacturing method includes injecting an electrolyte into the case 200. A specific injection operation includes, in this order, “(c1) attachment of a temporary sealing plug,” “(c2) insertion of a nozzle,” “(c3) injection of an electrolyte,” and “(c4) removal of the nozzle.”

[0029] (c1) Installation of temporary sealing plug 6 is a second schematic diagram showing a method for manufacturing a storage cell in this embodiment. This manufacturing method includes attaching the temporary sealing plug 10 to the liquid injection port 221. For example, the temporary sealing plug 10 may be press-fitted into the liquid injection port 221. The temporary sealing plug 10 may be attached at any timing. For example, the temporary sealing plug 10 may be attached in "(a) Preparation of the case" or "(b) Storage of the electrode body".

[0030] (c2) Inserting the nozzle 7 is a third schematic diagram showing a method for producing an energy storage cell in this embodiment. The method includes inserting a nozzle 20 into the notch 16 of the temporary sealing plug 10. The nozzle 20 may be inserted, for example, near the geometric center of the temporary sealing plug 10.

[0031] (c3) Injection of electrolyte The manufacturing method includes injecting an electrolyte from a nozzle 20. The temporary sealing plug 10 can block the electrolyte from splashing back.

[0032] (c4) Removing the nozzle This manufacturing method includes pulling out the nozzle 20 from the temporary sealing plug 10. After a predetermined amount of electrolyte is injected, the nozzle 20 is pulled out. The restoring force of the temporary sealing plug 10 can close the incision 16. That is, the temporary sealing plug 10 returns to the state shown in FIG. 6. When the center portion 12 of the temporary sealing plug 10 is raised, the center portion 12 may be clamped by a clamp 30 (see FIG. 3).

[0033] (d) Initial charging The manufacturing method may include performing an initial charge. During the initial charge, gas is generated due to decomposition of the electrolyte. Due to an increase in internal pressure, the slit 16 of the temporary sealing plug 10 may be slightly opened. The gas may be released from the slit 16. During the initial charge, the temporary sealing plug 10 may reduce volatilization of the electrolyte.

[0034] (e) Sealing 8 is a fourth schematic diagram showing a method for producing a storage cell in this embodiment. This production method may further include blocking the liquid injection port 221 with a sealing plug 224. The sealing plug 224 may be attached while the temporary sealing plug 10 remains. That is, the temporary sealing plug 10 is disposed between the liquid injection port 221 and the sealing plug 224. For example, the sealing plug 224 may be welded to the case 200 by laser processing.

[0035] 3. Energy storage cells A storage cell suitable for this manufacturing method will be described below. Fig. 9 is a schematic cross-sectional view showing an example of a storage cell in this embodiment. The storage cell 1 includes a temporary sealing plug 10, a sealing plug 224, a case 200, an electrode body 100, and an electrolyte (not shown). The electrolyte is a liquid electrolyte. The electrolyte may include, for example, an organic solvent and a lithium salt.

[0036] The energy storage cell 1 may have, for example, a height direction, a width direction, and a thickness direction. The height direction, width direction, and thickness direction are perpendicular to one another. The "height direction" is the H direction in FIG. 9, etc. The "width direction" is the W direction in FIG. 9, etc. The "thickness direction" is the T direction in FIG. 10, etc. 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" refers to the dimension in the height direction. "Width" refers to the dimension in the width direction. "Thickness" refers to the dimension in the thickness direction, or the thickness of an object.

[0037] The case 200 houses the electrolyte and the electrode assembly 100. The case 200 may be sealed. The case 200 may be sealed. The case 200 may be composed of a plurality of members. The case 200 may have a rectangular parallelepiped shape. The case 200 may include, for example, a can 210 and a lid 220. The can 210 includes a bottom wall 212 and a peripheral wall 214. The width of the peripheral wall 214 may be greater than the thickness of the peripheral wall 214. The height of the peripheral wall 214 may be greater than the thickness of the peripheral wall 214. Note that the "thickness of the peripheral wall 214" here refers to the outer dimension of the case 200 in the depth direction of FIG. 9.

[0038] The lid 220 closes the opening of the can 210. The lid 220 may be, for example, flat. The lid 220 may include, for example, a pressure release valve 222. The pressure release valve 222 releases the internal pressure of the case 200. When the internal pressure reaches or exceeds a set value, the pressure release valve 222 can be opened. The sealing plug 224 seals the liquid filling port 221. The temporary sealing plug 10 is disposed between the liquid filling port 221 and the sealing plug 224.

[0039] The electrode body 100 may have, for example, a cubic outer shape. The electrode body 100 may have, for example, a rectangular parallelepiped outer shape. The electrode body 100 may have, for example, a flat rectangular parallelepiped shape. The electrode body 100 may be covered with, for example, an insulating film (not shown).

[0040] The "first aspect ratio" refers to the ratio of the width to the height in the electrode body 100. The first aspect ratio may be, for example, 1 or more, 1.5 or more, 2 or more, 2.5 or more, 3 or more, 5 or more, or 10 or more. The first aspect ratio may be, for example, 10 or less, 5 or less, 3 or less, 2.5 or less, 2 or less, or 1.5 or less. The "second aspect ratio" refers to the ratio of the thickness to the height in the electrode body 100. The second aspect ratio may be, for example, 0.1 or more, 0.2 or more, 0.3 or more, 0.5 or more, or 1 or more. The second aspect ratio may be, for example, 1 or less, 0.5 or less, 0.3 or less, or 0.2 or less.

[0041] The electrode body 100 may have any structure. The electrode body 100 may be, for example, a wound type. The electrode body 100 may be, for example, a laminated type.

[0042] FIG. 10 is a schematic cross-sectional view showing an example of an electrode assembly in this embodiment. The electrode assembly 100 in FIG. 10 is a laminated type. The electrode assembly 100 includes one or more first electrodes 110, one or more second electrodes 120, and one or more separators 130. In the T direction, the first electrodes 110 and the second electrodes 120 are alternately laminated. That is, the T direction of the storage cell 1 is parallel to the lamination direction of the first electrodes 110 and the second electrodes 120. The number of the first electrodes 110 and the second electrodes 120 may be any of 2 or more, 5 or more, 10 or more, 50 or more, or 100 or more. The number of the first electrodes 110 and the second electrodes 120 may be any of 200 or less, 100 or less, 50 or less, 10 or less, or 5 or less.

[0043] The second electrode 120 has a different polarity than 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.

[0044] The first electrode 110 may include, for example, a first current collector 112 and a first active material layer 114. The first current collector 112 may include, for example, a metal foil or the like. The metal foil may include, for example, Al, Cu, Ni, Ti, Fe, or the like. The first active material layer 114 is disposed on a surface of the first current collector 112. The first active material layer 114 may be disposed on only one side of the first current collector 112. The first active material layer 114 may be disposed 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 include, for example, a lithium nickel composite oxide, or the like. The negative electrode active material may include, for example, graphite, SiO, Si, or the like.

[0045] 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 a surface of the second current collector 122. The second active material layer 124 may be disposed on only one side of the second current collector 122. The second active material layer 124 may 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 of 1.01 or more, 1.05 or more, or 1.1 or more. 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 of 1.1 or less, 1.05 or less, or 1.01 or less.

[0046] 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, 5 to 50 μm, 5 to 30 μm, or 5 to 15 μm. The separator 130 separates the first electrode 110 from the second electrode 120. The separator 130 may be, for example, two or more sheets. For example, the separator 130 may be inserted between each of the first electrode 110 and the second electrode 120.

[0047] Separator 130 may be, for example, a single sheet. For example, separator 130 may include zigzag fold portion 135. Separator 130 is folded in a zigzag shape at zigzag fold portion 135. The zigzag shape may also be expressed as, for example, a "bellows shape" or an "accordion shape."

[0048] The zigzag fold portion 135 includes a flat portion 131 and a folded portion 132. In the flat portion 131, the separator 130 extends in a flat shape. In the folded portion 132, the separator 130 is folded. The folded portion 132 is disposed at both ends in the H direction. The separator 130 is folded so as to alternately sandwich the first electrode 110 or the second electrode 120. The flat portion 131 sandwiches the first electrode 110 or the second electrode 120. The separator 130 may further include, for example, an outer peripheral portion 136. The outer peripheral portion 136 may be wound so as to wrap the zigzag fold portion 135. Note that the zigzag fold portion may be formed by folding the separator 130 at both ends in the W direction.

[0049] The energy storage cell 1 further includes external terminals 300. The pair of external terminals 300 are fixed to the lid 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 contain Al, Cu, Ni, or the like. The external terminals 300 may have, for example, a rectangular parallelepiped shape. The external terminals 300 may be connected to a bus bar (not shown).

[0050] The pair of connecting members 400 connect the electrode tabs and the external terminals 300. The electrode tabs indicate the first electrode tabs 116 or the second electrode tabs 126. The two connecting members 400 may have substantially the same structure.

[0051] The connecting member 400 may include, for example, a current collecting tab 410, a sub-tab 420, and a connecting pin 430. The current collecting tab 410 includes a side portion 412 and an upper portion 414. The side portion 412 is located on a side of the electrode body 100 in the W direction. The upper portion 414 is located above the electrode body 100. The upper portion 414 extends from an upper end of the side portion 412 toward the inside in the W direction.

[0052] The sub-tab 420 connects the electrode tabs to the current collecting tab 410. The sub-tab 420 may include a first end 422 and a second end 424. The first end 422 is connected to the electrode tabs. The second end 424 is connected to the side portion 412.

[0053] The connecting pin 430 connects the current collecting tab 410 to the external terminal 300. The connecting pin 430 connects the upper portion 414 to the external terminal 300. For example, a lower end of the connecting pin 430 may be inserted into a through hole provided in the upper portion 414.

[0054] The insulating member 500 insulates the case 200 from the connecting member 400. The insulating member 500 may include a first portion 510, a second portion 520, a third portion 530, and a fourth portion 540, for example.

[0055] The first part 510 is fixed to the upper surface of the lid 220. The first part 510 is disposed between the lid 220 and the external terminal 300. The second part 520 is fixed to the lower surface of the lid 220. The second part 520 is disposed between the lid 220 and the upper part 414. The second part 520 is disposed between the lid 220 and a lower part of the connecting pin 430. The third part 530 is disposed between the connecting pin 430 and the lid 220. The third part 530 is cylindrical. The third part 530 surrounds the connecting pin 430. The first part 510, the second part 520 and the third part 530 are provided with through holes. The connecting pin 430 is inserted through the through holes.

[0056] The fourth part 540 is plate-shaped. It is fixed to the lower surface of the upper part 414. The fourth part 540 is disposed above the electrode body 100. In the fourth part 540, a through hole is provided below the pressure release valve 222. In the fourth part 540, a through hole is also provided below the liquid injection port 221. [Explanation of symbols]

[0057] 1 storage cell, 10 temporary sealing plug, 12 center, 14 peripheral portion, 16 notch, 20 nozzle, 30 clamp, 100 electrode body, 110 first electrode, 112 first current collector, 114 first active material layer, 116 first electrode tab, 120 second electrode, 122 second current collector, 124 second active material layer, 126 second electrode tab, 130 separator, 131 flat portion, 132 folded portion, 135 zigzag portion, 136 outer periphery, 200 case, 210 can, 212 bottom wall, 214 peripheral wall, 220 lid, 221 liquid inlet, 222 pressure release valve, 224 sealing plug, 300 external terminal, 400 connecting member, 410 current collector tab, 412 side portion, 414 Upper portion, 420, subtab, 422, first end, 424, second end, 430, connecting pin, 500, insulating member, 510, first part, 520, second part, 530, third part, 540, fourth part.

Claims

1. A temporary sealing plug for temporarily closing a liquid injection port of a storage cell after liquid injection, Includes a central portion and a peripheral portion, In a plan view, the peripheral portion surrounds the central portion, and A cut is formed extending radially from the center portion to the peripheral portion. Temporary sealing plug.

2. At least one selected from the group consisting of ethylene propylene diene rubber, perfluoroalkoxy fluororesin, and polytetrafluoroethylene; The temporary sealing plug according to claim 1.

3. The central portion is raised. The temporary sealing plug according to claim 1.

4. The temporary sealing plug, the sealing plug, the case, the electrode body, and the electrolyte solution according to any one of claims 1 to 3 are included, The case accommodates the electrode body and the electrolyte, The case is provided with the liquid injection port, The sealing plug closes the liquid injection port, and The temporary sealing plug is disposed between the liquid injection port and the sealing plug. Energy storage cell.

5. (a) preparing a case having a liquid injection port; (b) housing an electrode body in the case; and (c) injecting an electrolyte into the case; Including, The (c) is (c1) attaching the temporary sealing plug according to any one of claims 1 to 3 to the liquid injection port; (c2) inserting a nozzle into the slit of the temporary sealing plug; (c3) injecting the electrolyte from the nozzle; and (c4) pulling out the nozzle from the temporary sealing plug; In this order: A method for manufacturing a storage cell.

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