Lithium battery liquid injection port sealing structure and battery

Abstract

The utility model relates to the technical field of batteries, in particular to a lithium battery liquid injection port sealing structure and a battery. The lithium battery liquid injection port sealing structure comprises a cover plate, a sealing rubber plug and a sealing aluminum sheet, and the cover plate is provided with a liquid injection hole; the cover plate comprises a main body piece and a stop piece, the main body piece is provided with the liquid injection hole, the stop piece is provided with a communicating part, a containing cavity is formed between the main body piece and the stop piece, and the containing cavity is communicated with the liquid injection hole and the communicating part; the sealing rubber plug is in interference fit with the liquid injection hole; the sealing aluminum sheet comprises a sealing piece used for being welded to the main body piece and a pressing piece used for being inserted into the liquid injection hole and driving the sealing rubber plug to completely move into the containing cavity. According to the battery, the stop piece is additionally arranged on the cover plate to receive and accommodate the sealing rubber plug on the basis of not influencing the passing of gas and liquid, so that the sealing rubber plug is effectively prevented from falling into the battery to influence the battery cell.

Description

TECHNICAL FIELD

[0001] The utility model relates to battery technology field especially relates to a lithium battery liquid injection port sealing structure and battery. BACKGROUND

[0002] The sealing mode of the liquid injection port of the square aluminum shell lithium battery is an important link in the battery manufacturing process. The sealing mode of the liquid injection port mainly involves the sealing between the battery top cover and the inside of the battery cell to ensure that the electrolyte inside the battery does not leak, and at the same time prevent external gas or moisture from entering the inside of the battery, affecting the performance and safety of the battery.

[0003] At present, the liquid injection port on the cover plate of the square aluminum shell battery is temporarily sealed by inserting a certain amount of helium and using a sealing plug after the liquid injection is completed, which isolates the air, moisture and dust inside and outside the liquid injection port. Then, the battery is transferred to the laser welding process of the liquid injection port, and a piece of sealing aluminum sheet is placed on the basis of the sealing plug inserted into the liquid injection port and laser welded with the cover plate to realize the complete sealing of the battery. Among them, since the sealing plug and the through hole of the liquid injection port are interference fit, the sealing plug and the liquid injection port are usually good in sealing. This makes the battery helium detection after laser welding of the sealing aluminum sheet, if the laser welding of the sealing aluminum sheet is poor with a gap, but the helium in the battery cannot leak out through the well-sealed sealing plug, which will cause false judgment of helium detection, and there is a safety risk. In addition, when the existing sealing aluminum sheet is laser welded, the sealing aluminum sheet may be placed off-center or position offset, which may cause problems such as explosive welding and poor welding marks, reducing the yield of laser welding.

[0004] The patent document with publication number CN220021565U discloses such a battery cover plate assembly and battery, which includes a cover plate, a sealing plug and a sealing aluminum sheet, the cover plate is provided with a liquid injection hole and a sealing groove communicated with the liquid injection hole, the sealing plug is arranged in the liquid injection hole, and the sealing aluminum sheet is arranged in the sealing groove. The sealing plug includes a sealing part and an insertion part connected with each other, and the diameter of the insertion part is smaller than that of the sealing part; the inner wall of the liquid injection hole has a first connecting section and a second connecting section arranged in sequence, the first connecting section is in interference fit with the sealing part, and the second connecting section is provided with a matching structure for forming a channel between the sealing part; the sealing aluminum sheet is provided with a pressing part, and the pressing part is used to drive the sealing plug to move downward along the liquid injection hole, so that the sealing part moves to the second connecting section.

[0005] In the prior art, on the one hand, the structure of the inner wall of the liquid injection hole and the sealing glue nail needs to be adjusted to form the air flow channel between the sealing part and the second connecting section, which puts higher requirements on the manufacturing precision of the liquid injection hole and the sealing glue nail, and there is a problem of cost increase. On the other hand, in order to form the air flow channel, the connecting area of the sealing glue nail and the inner wall of the liquid injection hole is small, and since the sealing glue nail is driven to move downward to form the air flow channel, a long part of the sealing glue nail is suspended in the battery and cannot be connected or supported, which makes the sealing glue nail easily fall off from the liquid injection hole and fall into the battery, thereby affecting the battery cell. Utility model content

[0006] The utility model solves the above problems, and provides a lithium battery liquid injection port sealing structure and battery which are low in cost and do not affect the battery.

[0007] The technical scheme for solving the problem of the utility model is to provide a lithium battery liquid injection port sealing structure, which comprises a cover plate, a sealing rubber plug and a sealing aluminum sheet, wherein the cover plate is provided with a liquid injection hole; the cover plate comprises a main body and a stopper arranged on one surface of the main body close to the inside of the battery, the main body is provided with the liquid injection hole, the stopper is provided with a communication part, a containing cavity is formed between the main body and the stopper, and the containing cavity is in communication with the liquid injection hole and the communication part; the sealing rubber plug is in interference fit with the liquid injection hole; and the sealing aluminum sheet comprises a sealing part for welding with the main body and a pressing part for being inserted into the liquid injection hole and driving the sealing rubber plug to move completely into the containing cavity.

[0008] As a preferred embodiment of the utility model, the main body is provided with a mounting groove for inserting the sealing part.

[0009] As a preferred embodiment of the utility model, the end of the liquid injection hole is convex in the direction away from the inside of the battery to form a nesting part, the sealing part is provided with a groove for inserting the nesting part, and the pressing part is arranged in the groove.

[0010] As a preferred embodiment of the utility model, the main body comprises a first connecting part and a mounting part for arranging the liquid injection hole; the stopper comprises a second connecting part and a containing part for forming the cavity wall of the containing cavity and arranging the communication part; and the first connecting part comprises a connecting section parallel to and connected with the second connecting part.

[0011] As a preferred embodiment of the utility model, the first connecting part further comprises a buffer section forming a force relieving groove between the second connecting section.

[0012] As a preferred embodiment of the utility model, the mounting part is convex in the direction close to the inside of the battery relative to the first connecting part.

[0013] As the preferred of the utility model, the one side of the installation part far from the battery interior, and the one side of the first connecting part far from the battery interior are connected through the first reverse round platform face, the one side of the installation part near the battery interior, and the one side of the first connecting part near the battery interior are connected through the second reverse round platform face.

[0014] As the preferred of the utility model, the taper of the first reverse round platform face is less than the taper of the second reverse round platform face.

[0015] As the preferred of the utility model, the stopper is provided with a plurality of the communication parts, and the guide direction of at least one of the communication parts is not parallel with the guide direction of the liquid injection hole.

[0016] Secondly, the utility model also has an aim to provide a kind of battery, including the lithium battery liquid injection port sealing structure as above.

[0017] The utility model has the advantages of:

[0018] 1.in the present application, before welding, the liquid injection hole can be sealed by sealing rubber plug;In the welding procedure, the lower pressing piece of sealing aluminum sheet can push the sealing rubber plug out of the liquid injection hole, and the sealing rubber plug cannot seal the liquid injection hole again, so that if the welding is poor, helium can be leaked to be detected, reliable inspection of helium detection process is realized, the appearance of liquid leakage battery cell and the entry of external moisture into the battery cell are prevented, and the safety risk caused by the flow of laser welding poor battery cell is avoided.

[0019] Among them, by additionally setting stopper on the cover plate to receive and accommodate sealing rubber plug without affecting the passage of gas and liquid, the influence of sealing rubber plug falling into the battery interior on the battery cell is effectively avoided, and the sealing rubber plug can be completely detached from the liquid injection hole, further preventing the sealing rubber plug from affecting the passage of helium due to the sealing of the liquid injection hole.In addition, this design only needs to install a stopper on the cover plate, without the need for fine adjustment of the structure of the inner wall of the liquid injection hole and the sealing rubber plug, and the cost is relatively low.

[0020] 2.In some embodiments, the end of the liquid injection hole is protruded to form a nesting part, and cooperates with the groove of the sealing piece, so that the welding place of the cover plate and the sealing aluminum sheet is not directly communicated with the inlet of the liquid injection hole in the vertical direction, which can prevent the welding slag and other foreign matters generated by laser welding of the sealing aluminum sheet from entering the battery cell, and improve the safety of the battery cell.Meanwhile, this cooperation also forms a positioning structure, which prevents the displacement of the sealing aluminum sheet, reduces the problems of laser welding such as explosive welding caused by the displacement or movement of the sealing aluminum sheet, and improves the yield of laser welding.

[0021] 3.In some embodiments, a force relief groove is provided to buffer the force of the sealing aluminum sheet pushing the sealing rubber plug downward, to prevent the problem of cover plate collapse and damage caused by downward pressure. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 is a structural schematic view of a lithium battery liquid injection port sealing structure;

[0023] Figure 2 is a use schematic view of a lithium battery liquid injection port sealing structure;

[0024] Figure 3 is a top view of a lithium battery liquid injection port sealing structure;

[0025] Figure 4 is a structural schematic view of a containing portion in a lithium battery liquid injection port sealing structure;

[0026] In the figure: cover plate 1, liquid injection hole 1a, communication portion 1b, containing cavity 1c, main body piece 11, first connecting portion 111, force relief groove 111a, mounting portion 112, stop piece 12, second connecting portion 121, containing portion 122, first reverse rounded trapezoidal face 113, second reverse rounded trapezoidal face 114, sealing rubber plug 2, sealing aluminum sheet 3, sealing piece 31, recess 311, lower pressing piece 32. DETAILED DESCRIPTION

[0027] The following is a specific implementation manner of the utility model, and the technical scheme of the utility model is further described in combination with the drawings, but the utility model is not limited to these embodiments.

[0028] A lithium battery liquid injection port sealing structure, as shown in Figures 1-3 , comprises a cover plate 1, a sealing rubber plug 2 and a sealing aluminum sheet 3, and the cover plate 1 is provided with a liquid injection hole 1a.

[0029] Among them, as shown in Figure 1 and Figure 2 , the cover plate 1 first comprises a main body piece 11, and the main body piece 11 is basically consistent with the traditional cover plate structure, and is provided with a liquid injection hole 1a thereon. For example, in some embodiments, the main body piece 11 is a flat plate structure, and the liquid injection hole 1a can be arranged at any place of the flat plate structure. In other embodiments, considering the subsequent need to install and weld the sealing aluminum sheet 3, in order to ensure the flatness of the surface of the cover plate and facilitate the installation and positioning of the sealing aluminum sheet 3, as shown in Figure 2 , the main body piece 11 is provided with a mounting groove. Specifically: the main body piece 11 comprises a first connecting portion 111 and a mounting portion 112, and the first connecting portion 111 and the mounting portion 112 are arranged in sequence. Figure 2In the direction of the mounting part 112, the horizontal plane of the upper surface of the mounting part 112 is lower than the horizontal plane of the upper surface of the first connecting part 111, thus forming a mounting groove between the side of the first connecting part 111 and the upper surface of the mounting part 112. The injection hole 1a is provided on the mounting part 112. When the sealing aluminum sheet 3 seals the injection hole 1a, it can be inserted into the mounting groove, and after insertion, the upper surface of the sealing aluminum sheet 3 is slightly lower than the upper surface of the first connecting part 111. After welding, the upper surface of the sealing aluminum sheet 3 can be made basically flush with the upper surface of the first connecting part 111, avoiding the problem of the protruding sealing aluminum sheet 3 being easily damaged by external forces and the seal being broken.

[0030] In embodiments where the mounting groove is provided in the main body 11, in some embodiments, the lower surface of the mounting portion 112 is flush with the lower surface of the first connecting portion 111. This may result in the mounting portion 112 being relatively thin and easily damaged. Therefore, in other embodiments, such as Figure 2 As shown, the mounting portion 112 protrudes towards the inside of the battery relative to the first connecting portion 111. In other words, the lower surface of the mounting portion 112 protrudes towards the inside of the battery relative to the lower surface of the first connecting portion 111, so as to ensure or even increase the thickness of the mounting portion 112, so that the mounting portion 112 can withstand greater pressure, thereby providing a more stable support foundation for the subsequent pressing and pushing of the sealing aluminum sheet 3 against the sealing plug 2.

[0031] In an embodiment where the mounting portion 112 protrudes towards the interior of the battery relative to the first connecting portion 111, since the first connecting portion 111 and the mounting portion 112 are not on the same horizontal plane, a connection structure is also provided between the first connecting portion 111 and the mounting portion 112. In some embodiments, the upper surface of the mounting portion 112 and the upper surface of the first connecting portion 111 are connected by a vertical plane, and the lower surface of the mounting portion 112 and the lower surface of the first connecting portion 111 are connected by a vertical plane. In other embodiments, such as... Figure 2 As shown, the side of the mounting portion 112 away from the battery interior and the side of the first connecting portion 111 away from the battery interior are connected by a first frustum-shaped surface 113. The side of the mounting portion 112 near the battery interior and the side of the first connecting portion 111 near the battery interior are connected by a second frustum-shaped surface 114. Compared to a vertical surface, the inclined frustum-shaped surface can distribute the force on the mounting portion 112 to the first connecting portion 111, improving the stability of the mounting portion 112. Furthermore, in some embodiments, the taper of the first frustum-shaped surface 113 is smaller than the taper of the second frustum-shaped surface 114, further improving the stability of the mounting portion 112.

[0032] The cover plate 1 further includes a stop 12 disposed on the side of the main body 11 near the inside of the battery. The stop 12 serves to receive and accommodate the sealing plug 2 while not obstructing the passage of gas and liquid. Figure 2As shown, the stopper 12 comprises a second connecting part 121 and a receiving part 122. The second connecting part 121 is parallel to and connected with the first connecting part 111. The parallel structure increases the connecting area of the two parts, thereby improving the connecting strength between the stopper 12 and the main body 11. In some embodiments, as shown in Figure 2 As shown, the first connecting part 111 comprises a connecting section and a buffer section. The lower surface of the buffer section is higher than that of the connecting section, and the buffer section is located between the connecting section and the mounting part 112. This makes the second connecting part 121 only abut and connect with the connecting section when the second connecting part 121 is connected with the first connecting part 111, and forms a groove between the second connecting part 121 and the buffer section. The groove is a stress relief groove 111a, which allows the mounting part 112 and the buffer section to slightly bend and elastically deform downward relative to the connecting section when the mounting part 112 is subjected to a downward pressure, thereby avoiding damage to the cover plate 1 caused by stress concentration.

[0033] The receiving part 122 is convex relative to the second connecting part 121 and towards the inside of the battery. Its shape is not limited and can be, for example, Figure 4 As shown, a circular truncated cone, a sphere, a cone, a cube, etc. When the second connecting part 121 is connected with the first connecting part 111, a cavity, i.e., a receiving cavity 1c, is formed between the receiving part 122 and the mounting part 112 of the cover plate 1. In order to be able to accommodate the sealing plug 2 later, the volume of the receiving cavity 1c should be greater than the volume of the sealing plug 2. In particular, the height of the receiving cavity 1c, i.e., the vertical distance from the mounting part 112 to the receiving part 122, should be greater than the height of the sealing plug 2, so as to ensure that the sealing plug 2 can fall completely into the receiving cavity 1c. Of course, in order not to affect the passage of gas and liquid, a communication part 1b is also provided on the receiving part 122. This makes the liquid injection hole 1a of the mounting part 112, the receiving cavity 1c, and the communication part 1b communicate with each other, so that the liquid can enter the inside of the battery from the liquid injection hole 1a, pass through the receiving cavity 1c and the communication part 1b in turn, and the gas in the inside of the battery can also pass through the communication part 1b, the receiving cavity 1c, and the liquid injection hole 1a in turn. The shape and size of the communication part 1b are not limited and only need to be able to allow gas and liquid to pass through and stop the sealing plug 2 from passing through. Preferably, multiple communication parts 1b are provided to ensure the flow effect. For example, Figure 4 As shown, the receiving part 122 is connected by a plurality of strip-shaped grids. The communication part 1b is formed between adjacent strip-shaped grids, and the distance between adjacent strip-shaped grids is less than the maximum width of the sealing plug 2 to limit the passage of the sealing plug 2. The position where the communication part 1b is provided is not limited and can be only at the bottom of the receiving part 122, or at both the side and bottom of the receiving part 122, or as shown in Figure 4 In the embodiment, the communication part 1b is only provided at the side of the receiving part 122. Since the communication part 1b is provided at the bottom, the sealing plug 2 may cover the communication part 1b after falling into the receiving cavity 1c, thereby affecting the flow of gas and liquid. Therefore, it is preferred thatFigure 4 The side part of the shown embodiment is provided with a communication part 1b. Specifically: the guide direction of at least one communication part 1b is non-parallel to the guide direction of the liquid injection hole 1a, such as shown in Figure 2 As shown, the guide direction of the liquid injection hole 1a is the up-down direction, and the communication part 1b provided on the side wall of the accommodating part 122 is the left-right direction, i.e. non-parallel to the guide direction of the liquid injection hole 1a.

[0034] The structure of the sealing rubber plug 2 is not limited, as long as it can be inserted into the liquid injection hole 1a with interference, and seal the liquid injection hole 1a.

[0035] The sealing aluminum sheet 3 includes a sealing part 31 for welding with the main body part 11, and a pressing part 32 for inserting into the liquid injection hole 1a to drive the sealing rubber plug 2 to move completely into the accommodating cavity 1c. In the embodiment where the cover plate 1 is provided with a mounting groove, the shape of the sealing part 31 is matched with the shape of the mounting groove, such as shown in Figure 1 As shown, the gap between the side wall of the sealing part 31 and the groove wall needs to be welded. In some embodiments, the sealing part 31 is a flat plate structure, and the pressing part 32 is directly connected with the lower surface of the sealing part 31. In this embodiment, the welding position of the sealing part 31 and the cover plate 1 is above the entrance of the liquid injection hole 1a, and there is a problem that the welding slag and other foreign matters generated from the welding position fall into the space between the sealing part 31 and the cover plate 1, and then enter the battery interior from the liquid injection hole 1a. Therefore, in other embodiments, as shown in Figure 2 As shown, the end part of the liquid injection hole 1a is protruded in the direction away from the battery interior to form a nesting part 13, and in the embodiment where the mounting groove is provided, the nesting part 13 should not exceed the height of the upper surface of the first connecting part 111. At the same time, the sealing part 31 is provided with a groove 311 for the nesting part 13 to insert, and the pressing part 32 is arranged in the groove 311. In this embodiment, the height of the entrance of the liquid injection hole 1a is increased, and when the welding slag and other foreign matters generated from the welding position fall into the space between the sealing part 31 and the cover plate 1, they will only gather outside the nesting part 13, and cannot continue to move upward into the nesting part 13 and enter the liquid injection hole 1a.

[0036] Based on the above structure, the sealing structure of the application is used, first, the sealing rubber plug 2 is pre-pressed in the liquid injection hole 1a after the second injection of the battery cell, the sealing rubber plug 2 is not pressed dead, and the gap is reserved. Then, the negative pressure is extracted to inject helium into the battery cell for helium detection in the subsequent process, the sealing rubber plug 2 is fully pressed after the helium injection, and the sealing rubber plug 2 and the upper hole of the liquid injection hole 1a are flush. Since the sealing rubber plug 2 and the liquid injection hole 1a are interference fit, the sealing rubber plug 2 can temporarily ensure the sealing between the inside and outside of the battery cell, and prevent the intrusion of external air and foreign matter during the process. Secondly, the battery cell is transferred to the sealing aluminum sheet welding process, which needs to ensure the same dew point environment as the liquid injection process. The sealing aluminum sheet 3 is embedded in the liquid injection hole 1a, the groove 311 of the sealing aluminum sheet 3 is sleeved on the nest part 13, and is connected with each structure of the liquid injection hole 1a, and the upper end of the sealing aluminum sheet 3 is slightly lower than the upper end of the cover plate 1. The lower pressing piece 32 of the lower end of the sealing aluminum sheet 3 pushes the sealing rubber plug 2 into the containing cavity 1c, and then the laser welding of the sealing aluminum sheet 3 is started. Since the sealing rubber plug 2 is pushed into the containing cavity 1c, the sealing aluminum sheet 3 and the cover plate 1 are basically hard structures and cannot be sealed, when the welding is poor, helium can slowly leak out through the small gap to be detected.

[0037] A battery includes a shell, a battery cell arranged in the shell, and the above-mentioned lithium battery liquid injection port sealing structure. Since the battery uses the above-mentioned sealing structure, if there is a gas leakage defect in the laser welding of the sealing aluminum sheet 3 and the cover plate 1, helium can be discharged through the communication part 1b, the containing cavity 1c, and the liquid injection hole 1a in turn and be detected, so that the helium detection equipment can accurately detect the battery whose sealing aluminum sheet 3 welding quality does not meet the requirements, thereby improving the safety of the battery.

[0038] The specific embodiments described herein are merely illustrative of the spirit of the present application. Those skilled in the art of the present application can make various modifications or supplements to the described specific embodiments or use similar ways to replace them, without deviating from the spirit of the present application or exceeding the scope defined by the appended claims.

Claims

1. A sealing structure of a lithium battery liquid injection port, comprising a cover plate (1), a sealing rubber plug (2) and a sealing aluminum sheet (3), wherein the cover plate (1) is provided with a liquid injection hole (1a); characterized in that: the cover plate (1) comprises a main body (11) and a stopper (12) arranged on the main body (11) near the inner part of the battery, the main body (11) is provided with the liquid injection hole (1a), the stopper (12) is provided with a communication part (1b), and a containing cavity (1c) is formed between the main body (11) and the stopper (12), and the containing cavity (1c) is in communication with the liquid injection hole (1a) and the communication part (1b); the sealing rubber plug (2) is in interference fit with the liquid injection hole (1a); the sealing aluminum sheet (3) comprises a sealing part (31) for welding with the main body (11) and a pressing part (32) for being inserted into the liquid injection hole (1a) and driving the sealing rubber plug (2) to move completely into the containing cavity (1c). The main body (11) is provided with a mounting groove for inserting the sealing part (31). The end of the liquid injection hole (1a) protrudes in the direction away from the inner part of the battery to form a nesting part (13), the sealing part (31) is provided with a groove (311) for inserting the nesting part (13), and the pressing part (32) is arranged in the groove (311). The main body (11) comprises a first connecting part (111) and a mounting part (112) for arranging the liquid injection hole (1a); the stopper (12) comprises a second connecting part (121) and a containing part (122) for forming the cavity wall of the containing cavity (1c) and arranging the communication part (1b); 2. The lithium battery liquid injection port sealing structure according to claim 1, characterized in that: The first connecting part (111) comprises a connecting section parallel to and connected with the second connecting part (121).

3. The sealing structure of the liquid injection port of a lithium battery according to claim 1 or 2, characterized in that: The first connecting part (111) further comprises a buffer section forming a relief groove (111a) between the second connecting part (121).

4. The seal structure for a lithium battery liquid injection port according to claim 1 or 2, wherein: The mounting part (112) protrudes in the direction close to the inner part of the battery relative to the first connecting part (111). The mounting part (112) is connected with the first connecting part (111) through a first reverse round truncated cone surface (113) on the side away from the inner part of the battery, and connected with the first connecting part (111) through a second reverse round truncated cone surface (114) on the side close to the inner part of the battery.

5. The lithium battery liquid injection port sealing structure according to claim 4, characterized in that: The taper of the first reverse round truncated cone surface (113) is smaller than that of the second reverse round truncated cone surface (114).

6. The lithium battery liquid injection port sealing structure according to claim 4, characterized in that: The stopper (12) is provided with a plurality of communication parts (1b), and the guide direction of at least one of the communication parts (1b) is non-parallel to the guide direction of the liquid injection hole (1a).

7. The lithium battery liquid injection port sealing structure according to claim 6, characterized in that: The sealing structure of the lithium battery liquid injection port according to any one of claims 1-9.

8. The lithium battery liquid injection port sealing structure according to claim 7, characterized in that: ​ 9. The lithium battery liquid injection port sealing structure according to claim 1, characterized in that: ​ 10. A battery, characterized by: ​

Images