JP7040475B2 - Power storage element - Google Patents

Description

The present invention relates to a technique for sealing a liquid injection hole for injecting an electrolytic solution.

Conventionally, a power storage element including an accommodating body in which a liquid injection hole for injecting an electrolytic solution is provided in a partition wall, and a plug member which is a plug member for sealing the liquid injection hole and has a shaft portion and a head portion. It has been known.
For example, in Patent Document 1, a liquid injection hole for injecting an electrolytic solution is provided in a battery case, and a sealing plug having a shaft portion and a head is press-fitted into the liquid injection hole to form a battery. A sealed battery to be welded to the case is described. In the sealed battery described in Patent Document 1, a space is provided between the upper half of the shaft portion of the sealing plug and the liquid injection hole so that the sealing plug can be press-fitted with a small force.

Japanese Unexamined Patent Publication No. 2009-146719

Normally, in the manufacturing process of the power storage element, the electrolytic solution is injected from the injection hole into the inside of the housing in a posture in which the injection hole opens upward. At that time, the electrolytic solution may adhere to the inner surface of the partition wall provided with the liquid injection hole. When the electrolytic solution adheres to the inner surface of the partition wall provided with the injection hole, the electrolytic solution becomes the inner peripheral surface of the shaft portion and the injection hole when the shaft portion of the plug member is subsequently inserted into the injection hole. There is a risk that it will rise due to capillarity through the gap. That is, there is a risk that the electrolytic solution will move to the outside. If the electrolytic solution moves to the outside, the electrolytic solution may enter between the partition wall and the head of the plug member, and welding defects may occur when the head is welded to the partition wall.

It can be said that the sealed battery described in Patent Document 1 described above has a structure in which the electrolytic solution does not easily rise because a space is provided between the upper half of the shaft portion of the sealing plug and the liquid injection hole. If the space is narrow, there is a risk that the electrolyte will rise.

In addition, the movement of the electrolytic solution due to the capillary phenomenon occurs regardless of the direction of gravity. Therefore, even when the injection hole opens in a direction other than above with respect to gravity, the electrolytic solution moves to the outside through between the shaft portion of the plug member and the inner peripheral surface of the injection hole. There is a risk of

The present specification discloses a technique for suppressing the amount of electrolytic solution that adheres to the inner surface of the partition wall and moves to the outside through between the shaft portion of the plug member and the inner peripheral surface of the liquid injection hole.

The power storage element disclosed by the present specification seals an accommodating body in which a liquid injection hole for injecting an electrolytic solution is provided in a partition wall, an electrode body housed in the accommodating body, and the liquid injection hole. A stopper member for stopping, comprising a stopper member having a head larger than the inner diameter of the injection hole and a shaft portion inserted into the injection hole, and surrounding the injection hole on the inner surface of the partition wall. A first concave portion or a convex portion surrounding the liquid injection hole is formed.

According to the power storage element disclosed by the present specification, it is possible to suppress the amount of the electrolytic solution that adheres to the inner surface of the partition wall and moves to the outside through between the shaft portion of the plug member and the inner peripheral surface of the liquid injection hole.

Perspective view of the battery according to the first embodiment Disassembled perspective view of the battery Cross-sectional view of the electrode body An exploded perspective view of a lid member, a positive electrode terminal, a negative electrode terminal, a positive electrode current collector, and a negative electrode current collector. Cross-sectional view of the injection hole Cross-sectional view of the injection hole Perspective view showing the vicinity of the liquid injection hole on the lower surface of the lid member. Cross-sectional view of the liquid injection hole according to the second embodiment Perspective view showing the vicinity of the liquid injection hole on the lower surface of the lid member. Cross-sectional view of the liquid injection hole according to the third embodiment Perspective view showing the vicinity of the liquid injection hole on the lower surface of the lid member. Sectional drawing which shows the recess which concerns on other embodiment Sectional drawing which shows the recess which concerns on other embodiment

(Outline of this embodiment)
First, an outline of the power storage element of the present embodiment will be described. This power storage element is an accommodating body in which a liquid injection hole for injecting an electrolytic solution is provided in a partition wall, an electrode body housed in the accommodating body, and a plug member for sealing the liquid injection hole. A first recess surrounding the injection hole on the inner surface of the partition wall is provided with a plug member having a head larger than the inner diameter of the injection hole and a shaft portion inserted into the injection hole. , A convex portion surrounding the liquid injection hole is formed.

According to this configuration, when the electrolytic solution is injected into the inside of the housing through the injection hole, the electrolytic solution adhering to the inner surface of the partition wall provided with the injection hole has a first concave portion or a convex portion. Reaching to the injection hole is suppressed. Therefore, as compared with the case where the first concave portion or convex portion is not provided, the amount of the electrolytic solution that moves to the outside due to the capillary phenomenon can be suppressed through between the shaft portion of the plug member and the inner peripheral surface of the liquid injection hole. As a result, it is possible to prevent the electrolytic solution from entering between the partition wall and the head of the plug member and causing welding defects.

<Embodiment 1>
Hereinafter, the battery 10, which is an embodiment of the power storage element, will be described with reference to the drawings.
1. 1. Battery Configuration With reference to FIGS. 1 to 4, the configuration of the battery 10 as the power storage element according to the first embodiment will be described. The battery 10 is a non-aqueous electrolyte secondary battery, more specifically a lithium ion secondary battery.

1-1. Appearance of Battery As shown in FIG. 1, the battery 10 includes a case 30. The case 30 includes a case main body 31 and a lid member 41. Case 30 is an example of a "container". Further, the lid member 41 is an example of a "bulkhead".

The case body 31 is formed in a box shape that opens upward by a metal such as an aluminum alloy or steel. More specifically, the case body 31 is a bottomed square cylinder having a long side in the X direction and a short side in the Z direction.

The lid member 41 is a metal member such as an aluminum alloy or steel, and is a rectangular plate material long in the X direction. The lid member 41 corresponds to the size of the opening of the case body 31, and is welded to the opening of the case body 31 to seal the opening of the case body 31.

A positive electrode terminal portion 70P and a negative electrode terminal portion 70N are provided on the upper surface (the outer surface of the case) V of the lid member 41. In the present embodiment, the positive electrode terminal portion 70P is arranged on the right side of FIG. 1, and the negative electrode terminal portion 70N is arranged on the left side.

1-2. Internal structure of the battery As shown in FIG. 2, the case main body 31 houses a positive electrode current collector 60P, a negative electrode current collector 60N, an electrode body 20, and an insulating cover 27. The positive electrode current collector 60P and the negative electrode current collector 60N are arranged separately on both sides of the lower surface W of the lid member 41 in the X direction. The positive electrode current collector 60P and the negative electrode current collector 60N are formed by bending an elongated conductive metal member, and each of them has a pair of facing walls 67 formed therein. The lower surface W is an example of the "inner surface".

The electrode body 20 is housed in the case 30 in a state where the entire electrode body 20 is covered with the insulating cover 27. The electrode body 20 will be described more specifically with reference to FIG. The electrode body 20 is wound in a long cylindrical shape with a separator 25 sandwiched between the positive electrode sheet 23P and the negative electrode sheet 23N while shifting their positions in different directions on the left and right. The positive electrode sheet 23P is formed by supporting a positive electrode active material on the surface of an aluminum foil. The negative electrode sheet 23N has a negative electrode active material supported on the surface of a copper foil.

Return to FIG. A positive electrode current collector foil 24P with exposed aluminum foil or copper foil is formed at one end of the positive electrode sheet 23P (see FIG. 3) described above. Further, a negative electrode current collector foil 24N with exposed copper foil is formed at the other end of the negative electrode sheet 23N (see FIG. 3) described above.

The positive electrode current collector 60P and the negative electrode current collector 60N face each other in the X direction with the electrode body 20 interposed therebetween. In the electrode body 20, the positive electrode current collector foil 24P is sandwiched by a pair of facing walls 67 provided on the positive electrode current collector 60P, and the negative electrode current collector foil 24P is sandwiched by the pair of facing walls 67 provided on the negative electrode current collector 60N. The 24N is sandwiched and fixed to the lid member 41.

1-3. Structure of the lid member Next, the structure of the lid member 41 will be described with reference to FIG. A first recess 43 and a second recess 44 are formed side by side on both sides in the X direction on the upper surface V of the lid member 41. The first recess 43 is square and the bottom of the gasket 75 is fitted. A rivet insertion hole 42 is formed at the bottom of the first recess 43. The second recess 44 is also square, and the bottom of the bolt case 85 is fitted.

A liquid injection hole 45 and a pressure release valve 49 are formed side by side in the central portion of the lid member 41. The injection hole 45 is provided for injecting the electrolytic solution into the case 30, and is sealed by the plug member 50 after the electrolytic solution is injected. The plug member 50 is made of metal and has a shaft portion 53 that is fitted and inserted into the liquid injection hole 45, and a head portion 51 that closes the liquid injection hole 45.

The positive electrode terminal portion 70P and the negative electrode terminal portion 70N have substantially the same structure, and the positive electrode current collector 60P and the negative electrode current collector 60N have substantially the same structure. 70P and the positive electrode current collector 60P will be described as an example.

The positive electrode terminal portion 70P includes a metal rivet 71P, a gasket 75, a metal terminal bolt 81P, a bolt case 85, and a metal terminal board 91P.

The rivet 71P is a double-screw type, and a first shaft portion 73 and a second shaft portion 74 are provided on both upper and lower sides of the head portion 72.

The gasket 75 is a synthetic resin material having an insulating property, and has a box shape capable of accommodating the head 72 of the rivet 71P. A through hole through which the first shaft portion 73 of the rivet 71P penetrates and an annular protrusion 76 along the peripheral edge thereof are formed on the bottom surface of the gasket 75.

The gasket 75 is arranged on the upper surface side of the lid member 41 while fitting the annular protrusion 76 into the rivet insertion hole 42, and insulates between the lid member 41 and the rivet 71P. Further, the inside of the gasket 75 is filled with a sealing material so as to seal around the rivet insertion hole 42 and around the rivet 71P.

The terminal bolt 81P is for attaching a terminal (not shown) provided in the harness connected to the electric device and a bus bar (not shown) for electrically connecting the batteries to each other, and the head 82 is attached to the bolt case 85. While accommodating, it is arranged side by side with the rivet 71P on the upper surface side of the lid member 41.

The bolt case 85 is a synthetic resin material having an insulating property like the gasket 75. The bolt case 85 has a box shape and accommodates the head 82 of the terminal bolt 81P. The bolt case 85 is arranged side by side with the gasket 75 on the upper surface side of the lid member 41, and is adhesively fixed to the lid member 41. A rotation control portion (not shown) is formed in the bolt case 85 to prevent the terminal bolt 81P from rotating.

The terminal board 91P is a flat metal plate long in the X direction, and has a first through hole 92 and a second through hole 93 formed therein. The terminal plate 91P is arranged on the upper surface side of the lid member 41, the second shaft portion 74 of the rivet 71P penetrates through the first through hole 92, and the terminal bolt 81P penetrates through the second through hole 93.

The resin plate 77 is a synthetic resin member having an insulating property. The resin plate 77 is a rectangle long in the X direction, and a through hole 78 is formed corresponding to the rivet insertion hole 42 of the lid member 41. Further, a receiving portion 77A capable of receiving the first connecting portion 61 of the positive electrode current collector 60P is formed on the lower surface of the resin plate 77. The resin plate 77 is arranged on the lower surface W side of the lid member 41, and insulates the lid member 41 and the positive electrode current collector 60P.

The positive electrode current collector 60P includes a flat plate-shaped first connecting portion 61 and a second connecting portion 65 that bends downward from the side end portion of the first connecting portion 61. The pair of facing walls 67 described above are formed in the second connecting portion 65.

In the rivet 71P, the second shaft portion 74 is crimped in a state where the second shaft portion 74 penetrates the first through hole 92 of the terminal plate 91P. Further, in the rivet 71P, the first shaft portion 73 penetrates in the order of the through hole of the gasket 75, the rivet insertion hole 42 of the lid member 41, the through hole 78 of the resin plate 77, and the through hole 62 of the positive electrode current collector 60P. The first shaft portion 73 is crimped in this state. As a result, the terminal plate 91P, the positive electrode current collector 60P, and the like are fixed to the lid member 41.

With the above configuration, the terminal bolt 81P on the positive electrode side is connected to the positive electrode sheet 23P via the terminal plate 91P, the rivet 71P, and the positive electrode current collector 60P.

1-4. Structure of Liquid Injection Hole and Plug Member Next, the structure of the liquid injection hole 45 and the plug member 50 will be described with reference to FIGS. 5 to 7. First, the lower surface of the lid member 41 will be described with reference to FIG. In FIG. 5, the alternate long and short dash line 120 indicates the position of the lower surface of the lid member 41. That is, the lower surface of the lid member 41 refers to the surface of the lid member 41 that faces downward other than the convex portion 101 and the concave portion 102.

As shown in FIG. 6, on the lower surface W of the lid member 41, a convex portion 101 that is convex downward with respect to the lower surface W is formed around the liquid injection hole 45. As shown in FIG. 7, the convex portion 101 is formed in a cylindrical shape. The inner diameter of the convex portion 101 is the same as the inner diameter of the liquid injection hole 45.

Further, as shown in FIG. 6, the lower surface W of the lid member 41 is formed with an annular recess 102 that is recessed upward with respect to the lower surface W so as to surround the convex portion 101. The recess 102 is an example of the second recess. The volume of the convex portion 101 protruding with respect to the lower surface W of the lid member is substantially equal to the internal volume of the concave portion 102 with respect to the lower surface W.

After the electrolytic solution is injected into the case body 31 from the liquid injection hole 45, the stopper member 50 is fitted and inserted into the liquid injection hole 45, and the outer peripheral edge of the head 51 is welded to the lid member 41 by laser light. Will be done. As shown in FIG. 6, the lower end of the shaft portion 53 is located above the lower end of the convex portion 101. In other words, the tip of the convex portion 101 protrudes from the tip of the shaft portion 53. Further, the shaft portion 53 is formed in a tapered shape in which the outer diameter becomes smaller toward the bottom. Therefore, the distance between the outer surface of the shaft portion 53 and the inner peripheral surface of the liquid injection hole 45 becomes wider toward the bottom.

2. 2. Explanation of Effect According to the battery 10 according to the first embodiment described above, since the convex portion 101 surrounding the liquid injection hole 45 is formed on the lower surface W of the lid member 41, the electrolytic solution 200 adhering to the lower surface W of the lid member 41 Is suppressed from reaching the liquid injection hole 45. Therefore, as compared with the case where the convex portion 101 is not provided, the amount of the electrolytic solution that moves to the outside due to the capillary phenomenon can be suppressed through between the shaft portion 53 of the plug member 50 and the inner peripheral surface of the liquid injection hole 45. As a result, it is possible to prevent the electrolytic solution from entering between the lid member 41 and the head portion 51 of the plug member 50, resulting in welding defects.

Further, according to the battery 10, since the concave portion 102 surrounding the convex portion 101 is formed, it is possible to more reliably prevent the electrolytic solution 200 adhering to the lower surface W of the lid member 41 from reaching the injection hole 45. ..

Further, according to the battery 10, the volume of the convex portion 101 protruding with respect to the lower surface W of the lid member is substantially equal to the internal volume of the concave portion 102 with respect to the lower surface W, so that the convex portion 101 is pressed (coining). Can be formed. Specifically, the convex portion 101 can be formed by the meat that escapes when the concave portion 102 is formed by press working.

Further, according to the battery 10, since the lower end of the shaft portion 53 of the plug member 50 is located above the lower end of the convex portion 101, the electrolytic solution 200 adhering to the lower surface of the convex portion 101 touches the shaft portion 53. Can be suppressed. As a result, it is possible to prevent the electrolytic solution 200 adhering to the lower surface of the convex portion 101 from moving to the outside due to the capillary phenomenon.

Further, according to the battery 10, the lower end side of the shaft portion 53 has a wide distance from the inner peripheral surface of the liquid injection hole 45. Therefore, the capillary phenomenon is less likely to occur on the lower end side of the shaft portion 53, and the electrolytic solution 200 adhering to the lower surface of the convex portion 101 can be more reliably suppressed from moving to the outside due to the capillary phenomenon.

<Embodiment 2>
Next, the second embodiment will be described with reference to FIGS. 8 to 9.
As shown in FIGS. 8 and 9, the lid member 41 according to the second embodiment has a concave portion 103 instead of a convex portion formed around the liquid injection hole 45. The recess 103 is an example of the first recess. The recess 103 has a tapered portion whose inner diameter increases toward the inside of the case body 31. Specifically, the recess 103 according to the second embodiment is a tapered portion as a whole. The second embodiment is substantially the same as the first embodiment in other respects.

According to the battery 10 according to the second embodiment described above, since the recess 103 surrounding the liquid injection hole 45 is formed in the lower surface W of the lid member 41, the electrolytic solution 200 adhering to the lower surface W of the lid member 41 is injected. Cannot reach hole 45. Therefore, as compared with the case where the recess 103 is not provided, the amount of the electrolytic solution that moves to the outside due to the capillary phenomenon can be suppressed through between the shaft portion 53 of the plug member 50 and the inner peripheral surface of the liquid injection hole 45.

Further, according to the battery 10, since the recess 103 has a tapered portion whose inner diameter increases toward the inside of the case main body 31, the electrolytic solution adhering to the tapered portion flows to the opposite side of the injection hole 45. As a result, it is possible to prevent the electrolytic solution 200 adhering to the inner peripheral surface of the recess 103 from moving to the outside due to the capillary phenomenon.

<Embodiment 3>
Next, the third embodiment will be described with reference to FIGS. 10 to 11.
As shown in FIGS. 10 and 11, the lid member 41 according to the third embodiment also has a recess 104 formed around the liquid injection hole 45. However, the recess 104 has a straight shape having a constant inner diameter in the vertical direction. The third embodiment is substantially the same as the second embodiment in other respects.

According to the battery 10 according to the third embodiment described above, since the recess 104 surrounding the liquid injection hole 45 is formed in the lower surface W of the lid member 41 as in the second embodiment, it adheres to the lower surface W of the lid member 41. The electrolytic solution 200 cannot reach the injection hole 45. Therefore, as compared with the case where the recess 104 is not provided, the amount of the electrolytic solution that moves to the outside due to the capillary phenomenon can be suppressed through between the shaft portion 53 of the plug member 50 and the inner peripheral surface of the liquid injection hole 45.

<Other embodiments>
The techniques disclosed herein are not limited to the embodiments described above and in the drawings, and for example, the following embodiments are also included in the technical scope disclosed herein.

(1) In the above embodiment, the lid member 41 has been described as an example as the partition wall. On the other hand, the partition wall may be a side wall or a bottom wall of the case body 31. Even when the injection hole 45 is provided on the wall of the case body 31, when the electrolytic solution is injected, the injection hole 45 is injected in a posture in which the injection hole 45 is open to the outside, so that the injection hole 45 is surrounded by the injection hole 45. By forming the concave portion of 1 or the convex portion surrounding the liquid injection hole 45, the electrolytic solution that moves to the outside by the capillary phenomenon through between the shaft portion 53 of the plug member 50 and the inner peripheral surface of the liquid injection hole 45. The amount can be suppressed.

(2) In the first embodiment, the case where the concave portion 102 is formed around the convex portion 101 has been described as an example, but the concave portion 102 may not be formed.

(3) In the first embodiment, the case where the inner diameter of the convex portion 101 is the same as the inner diameter of the liquid injection hole 45 has been described as an example. However, the inner diameter of the convex portion 101 may be larger than the inner diameter of the liquid injection hole 45.

(4) In the first embodiment, the case where the lower end of the shaft portion 53 is located above the lower end of the convex portion 101 has been described as an example. On the other hand, the lower end of the shaft portion 53 may be located below the lower end of the convex portion 101. For example, when the area of the lower surface of the convex portion 101 is small, the electrolytic solution adhering to the lower surface of the convex portion 101 is also small, so that the lower end of the shaft portion 53 moves to the outside even if it is located below the lower end of the convex portion 101. This is because the amount of electrolytic solution to be used is small.

(5) In the first embodiment, the case where the lower end of the convex portion 101 is located below the lower surface W of the lid member 41 has been described as an example. On the other hand, when the concave portion 102 is provided around the convex portion 101, the lower end of the convex portion 101 may be located at the same height as the lower surface W of the lid member 41 or above the lower surface W of the lid member 41.

(6) In the second embodiment, the case where the entire recess 103 is a tapered portion has been described as an example. On the other hand, as shown in FIGS. 12 and 13, the concave portion may have a shape having a tapered portion in part. Specifically, the recess 105 shown in FIG. 12 has a shape having a bottom surface parallel to the bottom surface W of the lid member 41 and a tapered portion extending downward from the outer circumference of the bottom surface. Further, the recess 106 shown in FIG. 13 has a shape having a tapered portion extending downward and a cylindrical portion extending downward from the outer periphery on the lower end side of the tapered portion.

(7) In the second embodiment, the case where the inner peripheral surface of the recess 103 has a tapered portion whose inner diameter increases as it goes down has been described as an example. On the other hand, the inner peripheral surface of the recess 103 may be formed in a spherical shape.

(8) In the above embodiment, the case where the shaft portion 53 of the plug member 50 is longer than the plate thickness of the lid member 41 has been described as an example. On the other hand, the shaft portion 53 may be shorter than the plate thickness of the lid member 41.

(9) In the above embodiment, a lithium ion secondary battery is exemplified as a power storage element. However, the power storage element is not limited to this. For example, the power storage element may be a battery other than a lithium ion secondary battery, or may be a capacitor such as an electric double layer capacitor.

10 ... Battery, 20 ... Electrode body, 30 ... Case, 31 ... Case body, 41 ... Lid member, 45 ... Liquid injection hole, 50 ... Plug member, 101. .. Convex, 102 ... Concave, 103 ... Concave, 104 ... Concave, 200 ... Electrolyte

Claims (3)

An accommodating body in which a liquid injection hole for injecting an electrolytic solution is provided in the partition wall, and
The electrode body housed in the housing body and
A plug member for sealing the liquid injection hole, the plug member having a head larger than the inner diameter of the liquid injection hole and a shaft portion inserted into the liquid injection hole.
Equipped with
A first recess surrounding the liquid injection hole is formed on the inner surface of the partition wall.
The first recess is a power storage element that is around the injection hole and is a recess formed continuously with the injection hole. The power storage element according to claim 1, wherein the first recess has a tapered portion whose inner diameter increases toward the inside of the housing. The power storage element according to claim 1 or 2, wherein the tip of the shaft portion protrudes from the first recess.

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