Power battery and liquid injection hole sealing structure thereof

Abstract

The invention relates to a power battery and a liquid injection hole sealing structure thereof. The liquid injection hole sealing structure comprises a deformation cylinder, a core cylinder and a sealing head. The power battery comprises a cover plate and the liquid injection hole sealing structure. By means of the gas channel formed by the through hole and the channel hole and the sealing fit between the sealing head and the deformation cylinder, the state of the liquid injection hole sealing structure and the inner wall of the liquid injection hole can be accurately controlled, and it is guaranteed that helium is injected and good sealing is conducted after helium is injected; and water is prevented from being mixed into the liquid injection hole in subsequent procedures or safety risks are prevented from being generated in the welding process of the liquid injection hole sealing structure.

Description

Technical Field

[0001] The present application relates to the technical field of lithium battery structural parts, and in particular to a power battery and a sealing structure for a liquid injection hole thereof. Background Art

[0002] At present, the square shell battery cells in power batteries are packaged with an aluminum shell and a top cover to accommodate the electrode group and electrolyte; an injection hole is provided on the top cover, and a sealing nail will be inserted after the electrolyte is injected to ensure the important guarantee of moisture control inside the battery cell before the sealing aluminum sheet is welded.

[0003] The existing sealing structure 10 is shown in Figures 1 and 2, and has a liquid injection hole matching section and an insertion section; wherein a slope notch is made in the insertion section to maximize the protection of the internal environment of the battery cell during the subsequent liquid injection, vacuum pumping and helium return processes. In the latter process, the battery cell will undergo secondary liquid injection → vacuum pumping and helium return + inserting sealing glue nails → liquid injection hole cleaning and sealing structure 10 welding.

[0004] However, it is difficult to control the accuracy of the above-mentioned sealing structure 10 when evacuating and returning helium, which often causes the electrolyte to be sucked out and contaminate the injection hole, seriously affecting the welding yield of the sealing structure 10. When the sealing structure 10 is welded, the residual electrolyte will produce gas at high temperature and cause welding explosion points. Summary of the invention

[0005] Based on this, it is necessary to provide a power battery and its injection hole sealing structure, as it is difficult to control the accuracy when evacuating and returning helium to the existing sealing structure, which often causes the electrolyte to be sucked out and contaminate the injection hole, seriously affecting the welding yield of the sealing structure. When the sealing structure is welded, the residual electrolyte will produce gas at high temperature, causing the welding explosion point problem.

[0006] A liquid injection hole sealing structure, the liquid injection hole sealing structure comprising:

[0007] A deformation cylinder, wherein the deformation cylinder has a deformation hole along its axial direction, and the deformation cylinder is sealed with the inner wall of the injection hole provided on the cover plate of the power battery;

[0008] A core barrel, wherein the core barrel has a passage hole along its axial direction, the core barrel is inserted into the deformation hole and slidably cooperates with the deformation barrel, and a through hole is opened on the side wall of one end of the core barrel close to the inside of the power battery;

[0009] A sealing head, the sealing head is connected to one end of the core barrel where the through hole is opened, and covers the opening of one end of the channel hole;

[0010] The core barrel has a first position and a second position that are switched along the deformation hole. In the first position, the sealing head is located outside the deformation hole, and the through hole and the channel hole can be connected to the interior of the power battery; in the second position, the sealing head partially enters the deformation hole and is sealed with the inner wall of the deformation hole.

[0011] In one embodiment, the liquid injection hole sealing structure further includes a liquid collecting cup, and one end of the liquid collecting cup has a cup opening;

[0012] The bottom wall of the liquid collecting cup is connected to the end of the core tube away from the sealing head, and covers the end of the channel hole away from the sealing head;

[0013] The bottom wall of the liquid collecting cup is provided with a connecting hole, and the connecting hole is used to connect the channel hole and the cup mouth.

[0014] In one embodiment, a portion of the core tube located between the liquid collecting cup and the deforming tube can be broken under tension, so that the liquid collecting cup can be separated from the core tube connected to the sealing head.

[0015] In one embodiment, the height of the broken end of the core tube away from the sealing head extending out of the deformation tube is less than or equal to 0.4 mm.

[0016] In one embodiment, the inner diameter and the outer diameter of the liquid collecting cup are synchronously expanded along the axial direction of the core barrel in a direction away from the sealing head.

[0017] In one embodiment, the injection hole sealing structure further includes an annular protrusion;

[0018] The deformation cylinder comprises a matching cylinder and a helium return cylinder connected to each other, the annular protrusion is located on the outer periphery of the matching cylinder, and the annular protrusion is sealed and matched with the inner wall of the injection hole;

[0019] The helium return cylinder is located on a side of the cover plate close to the inside of the power battery, and the through hole is formed on the side wall of the helium return cylinder.

[0020] In one embodiment, the outer diameter of one end of the deformable tube close to the sealing head gradually decreases along the axial direction of the deformable tube toward the sealing head.

[0021] In one embodiment, the material of the deformation tube is a mixture of rubber and polypropylene, so that after the sealing head enters the deformation hole, the side wall of the deformation tube is deformed along the radial direction of the deformation tube, and the sealing head is sealed and matched with the deformation tube.

[0022] In one embodiment, the core barrel is made of metal material.

[0023] An embodiment of the present application further provides a power battery, the power battery comprising: a cover plate and the injection hole sealing structure;

[0024] The cover plate is provided with a liquid injection hole;

[0025] The injection hole sealing structure is used to be inserted into the injection hole and to be gap-matched or sealingly abutted with the inner wall of the injection hole.

[0026] In actual use of the above-mentioned liquid injection hole sealing structure, the core barrel is first inserted into the channel hole, and then the deformable barrel is inserted into the liquid injection hole, wherein the end of the deformable barrel close to the sealing head is inserted into the liquid injection hole toward the inside of the battery. Since a through hole is provided on the side wall of the end of the core barrel close to the inside of the power battery, a gas channel is formed by the through hole and the channel hole. At this time, the core barrel is in the first position, and the inside of the liquid injection hole is vacuumed and helium is injected into the liquid injection hole in turn through the channel. Then, the core barrel is pulled out in a direction away from the inside of the battery, and the sealing head partially enters the deformable hole and seals with the inner wall of the deformable barrel, thereby making the through hole. The gas channel formed by the through hole and the channel hole is isolated from the inside of the battery, thereby sealing the injection hole through the sealing cooperation between the sealing head and the deformable cylinder. At this time, the core cylinder is in the second position, isolating the inside of the battery from the outside of the battery, and realizing the sealing of the injection hole. Finally, the sealing performance is tested. The present application uses the gas channel formed by the through hole and the channel hole and the sealing cooperation between the sealing head and the deformable cylinder to accurately control the state of the injection hole sealing structure and the inner wall of the injection hole, ensure the injection of helium and good sealing after the injection of helium, and avoid the mixing of moisture into the injection hole in the subsequent process or the safety risk caused by the welding process of the injection hole sealing structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] FIG. 1 is a schematic diagram showing the cooperation between a sealing structure and a cover plate of a battery in the prior art.

[0028] FIG. 2 is a schematic diagram of the sealing structure in FIG. 1 .

[0029] FIG. 3 is a schematic diagram showing the cooperation between the sealing structure of the liquid injection hole and the cover plate of the battery according to an embodiment.

[0030] FIG. 4 is a cross-sectional view of FIG. 3 .

[0031] FIG. 5 is an enlarged view of the sealing structure of the injection hole in FIG. 4 .

[0032] FIG. 6 is a schematic structural diagram of the sealing structure of the injection hole in FIG. 4 .

[0033] FIG. 7 is a schematic diagram of the sealing structure of the liquid injection hole in FIG. 4 with the liquid collecting cup removed.

[0034] FIG8 is an enlarged view of the sealing structure of the liquid injection hole in FIG7 with the liquid collecting cup removed.

[0035] Description of Figure Numbers:

[0036] 10- Sealing structure;

[0037] 100-liquid injection hole sealing structure;

[0038] 110-deformation cylinder; 111-deformation hole; 112-matching cylinder; 113-helium return cylinder;

[0039] 120-core barrel; 121-channel hole; 122-through hole;

[0040] 130-sealing head;

[0041] 140- annular protrusion; 141- liquid collecting cup; 142- connecting hole;

[0042] 210 - cover plate; 211 - injection hole. DETAILED DESCRIPTION

[0043] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present application, so the present application is not limited by the specific embodiments disclosed below.

[0044] In the description of the present application, it should be understood that if the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. appear, the orientation or position relationship indicated by these terms is based on the orientation or position relationship shown in the accompanying drawings, which is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application.

[0045] In addition, if the terms "first" or "second" appear, these terms are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of this application, if the term "plurality" appears, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0046] In this application, unless otherwise clearly specified and limited, if the terms "installed", "connected", "connected", "fixed" and the like appear, these terms should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integrated connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to the specific circumstances.

[0047] In the present application, unless otherwise clearly specified and limited, if there is a description that a first feature is "above" or "below" a second feature, etc., or similar descriptions appear, it may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature being "above", "above" and "above" the second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. The first feature being "below", "below" and "below" the second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0048] It should be noted that if an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be a central element. If an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. If any, the terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used in this application are for illustrative purposes only and do not represent the only implementation method.

[0049] Refer to Figure 3, which shows a structural schematic diagram of the injection hole sealing structure 100 in an embodiment of the present application inserted into the injection hole 211 of the cover plate 210 of the power battery. The injection hole sealing structure 100 provided in an embodiment of the present application includes: a deformable cylinder 110, a core cylinder 120 and a sealing head 130.

[0050] Referring to Fig. 3, Fig. 4 and Fig. 5, in the above-mentioned injection hole sealing structure 100, the deformable cylinder 110 has a deformable hole 111 along its axial direction, and the deformable cylinder 110 is sealed with the inner wall of the injection hole 211. The core cylinder 120 has a channel hole 121 along its axial direction, and the core cylinder 120 is penetrated through the deformable hole 111 and slidably cooperates with the deformable cylinder 110. The side wall of the end of the core cylinder 120 close to the inside of the power battery is provided with a through hole 122. The sealing head 130 is connected to the end of the core cylinder 120 where the through hole 122 is provided, and covers the opening of one end of the channel hole 121.

[0051] The core barrel 120 has a first position and a second position that can be switched along the deformation hole 111. In the first position, the sealing head 130 is located outside the deformation hole 111, and the through hole 122 and the channel hole 121 can be connected to the inside of the power battery. In the second position, the sealing head 130 partially enters the deformation hole 111 and seals with the inner wall of the deformation hole 111.

[0052] During actual use of the above-mentioned injection hole sealing structure 100, the core tube 120 is first inserted into the channel hole 121, and then the deformable tube 110 is inserted into the injection hole 211, wherein the end of the deformable tube 110 close to the sealing head 130 is inserted into the injection hole 211 toward the inside of the battery. Since a through hole 122 is provided on the side wall of one end of the core barrel 120 close to the interior of the power battery, the through hole 122 and the channel hole 121 form a gas channel. At this time, the core barrel 120 is in the first position, and the interior of the injection hole 211 is vacuumed and helium is injected into the injection hole 211 in turn through the channel, and then the core barrel 120 is pulled out in the direction away from the interior of the battery, and the sealing head 130 will partially enter the deformation hole 111 and seal with the inner wall of the deformation hole 111, so that the gas channel formed by the through hole 122 and the channel hole 121 is isolated from the interior of the power battery, thereby sealing the sealing head 130 with the deformation barrel 110. At this time, the core barrel 120 is in the second position, isolating the interior of the battery from the outside of the battery, achieving the sealing of the injection hole 211, and finally testing the sealing performance. The present application forms a gas channel through the through hole 122 and the channel hole 121 and seals with the deformation tube 110 through the sealing head 130, so as to accurately control the state of the injection hole sealing structure and the inner wall of the injection hole 211, thereby ensuring the injection of helium and good sealing after the injection of helium, and avoiding the mixing of moisture into the injection hole 211 in subsequent processes or safety risks during the welding of the injection hole sealing structure.

[0053] Specifically, the sealing head only needs to have a maximum inner diameter greater than the inner diameter of the deformation hole and be able to seal the deformation hole. It can be a cone head, a special-shaped head, and preferably a ball head. The ball head has a smooth surface and can enter the deformation hole more smoothly.

[0054] 5 and 6, in one embodiment, the liquid injection hole sealing structure 100 further includes a liquid collecting cup 141, and one end of the liquid collecting cup 141 has a cup opening. The bottom wall of the liquid collecting cup 141 is connected to the end of the core tube 120 away from the sealing head 130, and covers the end of the channel hole 121 away from the sealing head 130. The bottom wall of the liquid collecting cup 141 is provided with a connecting hole 142, and the connecting hole 142 is used to connect the channel hole 121 and the cup opening.

[0055] In this embodiment, the electrolyte inside the battery brought out during the vacuum pumping and helium return process enters the liquid collecting cup 141 through the through hole 122, the channel hole 121 and the connecting hole 142, thereby preventing the electrolyte from overflowing or spilling to other parts, effectively avoiding the contamination problem of the injection hole 211, and greatly reducing the risk of leakage due to poor welding of the sealing aluminum nail.

[0056] Referring to Figures 5, 6, 7 and 8, in one embodiment, the portion of the core barrel 120 located between the liquid collecting cup 141 and the deformation barrel 110 can be broken by tension, so that the liquid collecting cup 141 can be separated from the core barrel 120 connected to the sealing head 130, so that after the helium return operation is completed, the liquid collecting cup 141 can be pulled out to the outside of the power battery to drive the core barrel 120 to move to the outside of the battery, and the sealing head 130 enters the deformation hole 111 and seals with the inner wall of the deformation barrel 110 to isolate the interior of the battery from the external space to complete the sealing, and the liquid collecting cup 141 is continued to be pulled, and the portion of the core barrel 120 located between the liquid collecting cup 141 and the deformation barrel 110 can be broken by tension, so that the liquid collecting cup 141 can be separated from the core barrel 120 connected to the sealing head 130, so that the electrolyte in the liquid collecting cup 141 is separated from the core barrel 120, thereby preventing the electrolyte from overflowing or spilling to other parts, effectively avoiding the pollution problem of the injection hole 211, and greatly reducing the risk of leakage due to poor welding of the sealing aluminum nail.

[0057] In one embodiment, the height of the end of the broken core barrel 120 away from the sealing head 130 extending from the deformation barrel 110 is less than or equal to 0.4 mm. Preferably, the broken core barrel 120 is flush with the deformation barrel 110, that is, the height of the end of the broken core barrel 120 away from the sealing head 130 extending from the deformation barrel 110 is equal to 0.

[0058] 5 and 6 , in one embodiment, the inner diameter and the outer diameter of the liquid collecting cup 141 are synchronously and gradually expanded along the axial direction of the core tube 120 in a direction away from the sealing head 130, thereby increasing the accommodation space inside the liquid collecting cup 141, thereby being able to accommodate more electrolyte, preventing the extracted electrolyte from overflowing the liquid collecting cup 141 excessively, and avoiding functional failure of the liquid collecting cup 141.

[0059] Referring to FIG. 5 and FIG. 6 , in one embodiment, the injection hole sealing structure 100 further includes an annular protrusion 140. The deformation cylinder 110 includes a matching cylinder 112 and a helium return cylinder 113 connected to each other. The annular protrusion 140 is located on the outer periphery of the matching cylinder 112, and the annular protrusion 140 is sealed with the inner wall of the injection hole 211. The helium return cylinder 113 is located on the side of the cover plate 210 close to the inside of the power battery, and a through hole 122 is opened on the side wall of the helium return cylinder 113.

[0060] In this embodiment, the annular protrusion 140 is sealed with the inner wall of the liquid injection hole 211. At the same time, the side wall composed of the annular protrusion 140 and the matching cylinder 112 is relatively thick and not easy to deform. Therefore, after the annular protrusion 140 is inserted into the liquid injection hole 211, it can be stably sealed with the liquid injection hole 211. The side wall of the helium return cylinder 113 is relatively thin, so that after the sealing head 130 enters the helium return cylinder 113, the helium return cylinder 113 can be deformed and sealed with the sealing head 130, thereby ensuring the sealing of the inside and outside of the battery after the helium return is completed.

[0061] 5 and 6 , in one embodiment, the outer diameter of one end of the deformable tube 110 close to the sealing head 130 gradually decreases along the axial direction of the deformable tube 110 toward the sealing head 130, so that the deformable tube 110 is easier to insert into the injection hole 211. At the same time, the wall thickness of one end of the deformable tube 110 close to the sealing head 130 gradually decreases along the axial direction of the deformable tube 110 toward the sealing head 130, so that the end of the deformable tube 110 close to the sealing head 130 can be easily deformed, while the end away from the sealing head 130 is not easily deformed. Therefore, the sealing head 130 is relatively fixed through the deformation of the deformable tube 110, the deformation hole 111 is blocked, and the sealing stability is improved.

[0062] In one embodiment, the material of the deformation tube 110 is a mixture of rubber and polypropylene, so that after the sealing head 130 enters the deformation hole 111 , the side wall of the deformation tube 110 is deformed along the radial direction of the deformation tube 110 , and the sealing head 130 and the deformation tube 110 are sealed and matched.

[0063] In one embodiment, the core barrel 120 is made of metal material, preferably aluminum.

[0064] An embodiment of the present application further provides a power battery, which includes: a cover plate 210 and a liquid injection hole sealing structure 100 .

[0065] The cover plate 210 defines a liquid injection hole 211 .

[0066] The injection hole sealing structure 100 is used to be inserted into the injection hole 211 and to be gap-fitted or sealingly abutted with the inner wall of the injection hole 211 .

[0067] During actual use of the above-mentioned injection hole sealing structure 100, the core tube 120 is first inserted into the channel hole 121, and then the deformable tube 110 is inserted into the injection hole 211, wherein the end of the deformable tube 110 close to the sealing head 130 is inserted into the injection hole 211 toward the inside of the battery. Since a through hole 122 is provided on the side wall of one end of the core barrel 120 close to the interior of the power battery, the through hole 122 and the channel hole 121 form a gas channel. At this time, the core barrel 120 is in the first position, and the interior of the injection hole 211 is vacuumed and helium is injected into the injection hole 211 in turn through the channel, and then the core barrel 120 is pulled out in the direction away from the interior of the battery, and the sealing head 130 will partially enter the deformation hole 111 and seal with the inner wall of the deformation hole 111, so that the gas channel formed by the through hole 122 and the channel hole 121 is isolated from the interior of the power battery, thereby sealing the sealing head 130 with the deformation barrel 110. At this time, the core barrel 120 is in the second position, isolating the interior of the battery from the outside of the battery, achieving the sealing of the injection hole 211, and finally testing the sealing performance. The present application forms a gas channel through the through hole 122 and the channel hole 121 and seals with the deformation tube 110 through the sealing head 130, so as to accurately control the state of the injection hole sealing structure and the inner wall of the injection hole 211, thereby ensuring the injection of helium and good sealing after the injection of helium, and avoiding the mixing of moisture into the injection hole 211 in subsequent processes or safety risks during the welding of the injection hole sealing structure.

[0068] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0069] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be construed as limiting the scope of the patent application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent application shall be subject to the attached claims.

Claims

1. A liquid injection hole sealing structure, characterized in that: The liquid injection hole sealing structure comprises: A deformation cylinder, wherein the deformation cylinder has a deformation hole along its axial direction, and the deformation cylinder is sealed with the inner wall of the injection hole provided on the cover plate of the power battery; A core barrel, wherein the core barrel has a passage hole along its axial direction, the core barrel is inserted into the deformation hole and slidably cooperates with the deformation barrel, and a through hole is opened on the side wall of one end of the core barrel close to the inside of the power battery; A sealing head, the sealing head is connected to one end of the core barrel where the through hole is opened, and covers the opening of one end of the channel hole; The core barrel has a first position and a second position that are switched along the deformation hole. In the first position, the sealing head is located outside the deformation hole, and the through hole and the channel hole can be connected to the interior of the power battery; in the second position, the sealing head partially enters the deformation hole and is sealed with the inner wall of the deformation hole.

2. The sealing structure of the injection hole according to claim 1, characterized in that: The liquid injection hole sealing structure also includes a liquid collecting cup, one end of which has a cup opening; The bottom wall of the liquid collecting cup is connected to the end of the core tube away from the sealing head, and covers the end of the channel hole away from the sealing head; The bottom wall of the liquid collecting cup is provided with a connecting hole, and the connecting hole is used to connect the channel hole and the cup mouth.

3. The sealing structure of the injection hole according to claim 2, characterized in that: The portion of the core tube located between the liquid collecting cup and the deformation tube can be broken under tension, so that the liquid collecting cup can be separated from the core tube connected to the sealing head.

4. The sealing structure of the injection hole according to claim 2, characterized in that: The height of the broken end of the core tube away from the sealing head extending out of the deformation tube is less than or equal to 0.4 mm.

5. The sealing structure of the injection hole according to claim 2, characterized in that: The inner diameter and the outer diameter of the liquid collecting cup are synchronously and gradually expanded along the axial direction of the core barrel in a direction away from the sealing head.

6. The sealing structure of the injection hole according to claim 1, characterized in that: The liquid injection hole sealing structure also includes an annular protrusion; The deformation cylinder comprises a matching cylinder and a helium return cylinder connected to each other, the annular protrusion is located on the outer periphery of the matching cylinder, and the annular protrusion is sealed and matched with the inner wall of the injection hole; The helium return cylinder is located on a side of the cover plate close to the inside of the power battery, and the through hole is formed on the side wall of the helium return cylinder.

7. The sealing structure of the injection hole according to claim 1, characterized in that: The outer diameter of one end of the deformable tube close to the sealing head gradually decreases along the axial direction of the deformable tube toward the sealing head.

8. The sealing structure of the injection hole according to claim 1, characterized in that: The material of the deformation tube is a mixture of rubber and polypropylene, so that after the sealing head enters the deformation hole, the side wall of the deformation tube is deformed along the radial direction of the deformation tube, and the sealing head is sealed and matched with the deformation tube.

9. The sealing structure of the injection hole according to claim 1, characterized in that: The core barrel is made of metal material.

10. A power battery, characterized in that: The power battery comprises: a cover plate and a liquid injection hole sealing structure according to any one of claims 1 to 9; The cover plate is provided with a liquid injection hole; The injection hole sealing structure is used to be inserted into the injection hole and to be gap-matched or sealingly abutted with the inner wall of the injection hole.

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