Lithium battery with exhaust structure

Abstract

The utility model discloses a lithium battery with an exhaust structure, which belongs to the technical field of lithium batteries and comprises a cover plate, a battery cell and a shell, the cover plate and the shell are hermetically connected to form a sealed structure, and the battery cell is arranged in the shell; an exhaust device is installed on the cover plate and comprises a shell, an air outlet is formed in one end of the shell, an air inlet is formed in the other end of the shell, the air inlet extends into the sealing structure, and the air outlet is communicated with the atmosphere; an inner cavity is formed in the shell, and an exhaust channel is formed by the inner cavity, the air inlet and the air outlet; a sealing plug is movably arranged in the inner cavity and plugs the air inlet; and during exhausting, the sealing plug is separated from the air inlet under air pressure. The air exhausting device can solve the problem that the sealing cover of the air exhausting device is welded with the battery shell in the prior art, so that the piston is difficult to jack up during air exhausting, and the air exhausting is unsmooth.

Description

Technical Field

[0001] The utility model relates to the technical field of lithium batteries, in particular to a lithium battery with an exhaust structure. Background Art

[0002] Gas production inside the battery is an important cause of battery swelling. Whether the battery is cycled at room temperature, cycled at high temperature, or shelved at high temperature, it will swell to varying degrees. According to current research results, the essence of causing battery cell swelling is the decomposition of the electrolyte. There are two situations in which the electrolyte decomposes. One is that the electrolyte has impurities, such as water and metal impurities that cause the electrolyte to decompose and produce gas. The other is that the electrochemical window of the electrolyte is too low, causing decomposition during charging. Solvents such as EC and DEC in the electrolyte will produce free radicals after obtaining electrons. The direct consequence of the free radical reaction is the production of low-boiling hydrocarbons, esters, ethers and CO2. Gas production not only affects the overall shape of the battery, but also has a great impact on some other battery properties, including cycle life.

[0003] There are studies in the prior art on the discharge of gas generated inside the battery. For example, a Chinese patent document with the announcement number CN207967136U discloses a lithium battery injection hole sealing exhaust device, which includes a one-way valve and a sealing cover. The one-way valve is used to insert and seal the injection hole. The outer end of the one-way valve is provided with a flange bent toward the hole wall of the injection hole. The sealing cover is arranged on the outer side of the outer end of the one-way valve and covers the one-way valve. The outer edge of the sealing cover is fixed on the lithium battery shell. The interior of the sealing cover is provided with a first positioning column. The position of the first positioning column corresponds to the position of the flange and the first positioning column is against the flange. Although the device can realize the function of exhausting the injection hole, it is necessary to seal the valve body through the sealing cover and the piston. The sealing cover positions the piston through the second positioning column. Since the sealing cover is welded to the battery shell, it is difficult to lift the piston when exhausting, which may cause the problem of poor exhaust. Utility Model Content

[0004] The utility model aims to provide a lithium battery with an exhaust structure, which solves the problem that the sealing cover of the exhaust device in the prior art positions the piston through a second positioning column, the sealing cover is welded to the battery shell, and it is difficult to lift the piston during exhaust, which may lead to poor exhaust.

[0005] In order to achieve the above-mentioned purpose, the utility model provides a lithium battery with an exhaust structure, comprising a cover plate, a battery cell and a shell, the cover plate and the shell are sealed and connected to form a sealed structure, and the battery cell is arranged in the shell; an exhaust device is installed on the cover plate, and the exhaust device includes a shell, one end of the shell is provided with an air outlet, and the other end is provided with an air inlet, the air inlet extends into the sealing structure, and the air outlet is connected to the atmosphere; an inner cavity is provided in the shell, and the inner cavity, the air inlet and the air outlet form an exhaust channel; a sealing plug is movably provided in the inner cavity, and the sealing plug blocks the air inlet; when exhausting, the sealing plug and the air inlet are separated under air pressure.

[0006] Specifically, the shell includes an upper shell and a lower shell, and the upper shell and the lower shell are sealed and connected; a groove is provided in the upper shell, and an elastic member is provided in the groove, and the elastic member is fixedly connected to the sealing plug, and the elastic member presses the sealing plug and the air inlet.

[0007] Considering the sealing of the outer shell, preferably, the inner cavity is arranged in the lower shell, the bottom inner wall of the inner cavity is provided with a protruding step, and the air inlet passes through the step; the cross-section of the step is smaller than the end face of the sealing plug.

[0008] Furthermore, a boss is provided on the top wall of the groove, the air outlet passes through the boss, one end of the elastic member is connected to the boss, and the other end is connected to the sealing plug. The cross section of the sealing plug is smaller than the cross section of the inner cavity.

[0009] In order to ensure good bonding and sealing between the upper shell and the lower shell, preferably, the lower shell is provided with a positioning wall around the inner cavity, and the upper shell is provided with a positioning groove corresponding to the positioning wall, and the positioning wall and the positioning groove are engaged when the upper shell and the lower shell are connected. A joint seam is provided at the engagement point between the positioning wall and the positioning groove, and the joint seam is close to the bottom side of the positioning wall.

[0010] Furthermore, the cover plate is provided with a liquid injection hole, and the air inlet of the exhaust device is connected to the sealing structure through the liquid injection hole. The lower shell is sealed and connected to the cover plate, and the lower shell completely covers the liquid injection hole.

[0011] Optionally, an explosion-proof valve is provided on the cover plate, and the explosion-proof valve is independent of the exhaust device.

[0012] Compared with the existing known technologies, the technical solution provided by the utility model has the following beneficial effects:

[0013] The utility model provides a lithium battery with an exhaust structure. When the pressure inside the battery cell is relatively low, the sealing plug is tightly combined with the air inlet to seal the air inlet, thereby preventing moisture and air from the outside from entering the shell and affecting the performance of the battery cell. When the gas generated inside the battery cell increases the pressure inside the shell, the increased air pressure pushes the sealing plug to separate from the air inlet, the air inlet opens, and the gas in the shell is discharged through the exhaust channel to reduce the pressure inside the shell. When the pressure inside the shell is reduced to a certain extent, the sealing plug is reset to re-block the air inlet. The exhaust device has a one-way conduction function, and the air outlet is directly connected to the atmosphere, which can ensure smooth exhaust.

[0014] It will be apparent that elements or features described above in the context of a single embodiment may be used alone or in combination in other embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In the drawings, the sizes and proportions do not represent the sizes and proportions of actual products. The drawings are merely illustrative, and some non-essential elements or features are omitted for clarity.

[0016] Figure 1 It is a schematic diagram of the three-dimensional structure of a lithium battery in an embodiment of the utility model;

[0017] Figure 2 It is an embodiment of the utility model Figure 1 A schematic diagram of a top view structure of a lithium battery;

[0018] Figure 3 It is an embodiment of the utility model Figure 2 Schematic diagram of the cross-section structure at AA;

[0019] Figure 4 It is an embodiment of the utility model Figure 3 Enlarged view of point C in the middle.

[0020] Description of Reference Numerals

[0021] 100, cover plate; 110, injection hole; 120, explosion-proof valve; 200, shell; 300, exhaust device; 310, outer shell; 311, upper shell; 312, lower shell; 313, groove; 314, step; 315, boss; 316, positioning wall; 317, positioning groove; 318, joint seam; 320, inner cavity; 330, sealing plug; 340, elastic member; 350, air inlet; 360, air outlet. DETAILED DESCRIPTION

[0022] The present invention will be described in detail with reference to the accompanying drawings. What is described here is only a preferred embodiment of the present invention, and those skilled in the art can think of other ways to implement the present invention based on the preferred embodiment, and other ways also fall within the scope of the present invention.

[0023] Example

[0024] Reference Figure 1-Figure 4 , this embodiment provides a lithium battery with an exhaust structure, including a cover plate 100, a battery cell and a shell 200, the cover plate 100 and the shell 200 are sealed and connected to form a sealed structure, and the battery cell is arranged in the shell 200. An exhaust device 300 is installed on the cover plate 100, and the exhaust device 300 includes a shell 310, one end of the shell 310 is provided with an outlet 360, and the other end is provided with an inlet 350, the inlet 350 extends into the sealed structure, and the outlet 360 is connected to the atmosphere. An inner cavity 320 is provided in the shell 310, and the inner cavity 320, the inlet 350 and the outlet 360 form an exhaust channel. A sealing plug 330 is movably provided in the inner cavity 320, and the sealing plug 330 blocks the inlet 350. Under normal circumstances, the internal pressure of the battery cell is relatively small, and the sealing plug 330 is tightly combined with the inlet 350 to seal the inlet 350 to prevent external moisture and air from entering the shell 200 and affecting the performance of the battery cell. When the gas generated inside the battery cell increases the pressure inside the housing 200, the increased gas pressure pushes the sealing plug 330 to separate from the air inlet 350, the air inlet 350 opens, and the gas inside the housing 200 is discharged through the exhaust channel to reduce the pressure inside the housing 200. When the pressure inside the housing 200 is reduced to a certain extent, the sealing plug 330 is reset to block the air inlet 350 again. It can be seen that the exhaust device 300 has a one-way conduction function, and the air outlet 360 is directly connected to the atmosphere, which can ensure smooth exhaust.

[0025] The realization of the resetting function of the sealing plug 330 requires the help of external force. In this embodiment, the elastic member 340 is used as the external force source. Figure 4 As shown, considering the convenience of assembling the elastic member 340, the housing 310 includes an upper shell 311 and a lower shell 312, and the upper shell 311 and the lower shell 312 are sealed and connected. The upper shell 311 and the lower shell 312 are both configured as cylindrical structures, which are convenient for automatic machine clamping, loading and unloading, and assembly. A groove 313 is provided in the upper shell 311, and an elastic member 340 is provided in the groove 313. The elastic member 340 is fixedly connected to the sealing plug 330, and the elastic member 340 presses the sealing plug 330 and the air inlet 350. Among them, in this embodiment, the elastic member 340 mainly adopts a cylindrical coil spring, and other elastic elements can also be considered if conditions permit. The sealing plug 330 is made of rubber material and has a certain elasticity.

[0026] Furthermore, the inner cavity 320 is disposed in the lower shell 312, and a protruding step 314 is disposed on the inner wall of the bottom of the inner cavity 320, and the air inlet 350 passes through the step 314. The step 314 is more easily matched with the sealing plug 330, which can increase the sealing performance of the air inlet 350 and the sealing plug 330. The cross section of the step 314 is smaller than the end face of the sealing plug 330, which can ensure that the sealing plug 330 completely covers the step 314, thereby reducing the probability of air leakage.

[0027] On the other hand, for the convenience and stability of assembling the elastic member 340, in this embodiment, the top wall of the groove 313 is provided with a boss 315, the gas outlet 360 runs through the boss 315, one end of the elastic member 340 is connected to the boss 315, and the other end is connected to the sealing plug 330. As mentioned above, the elastic member 340 adopts a cylindrical coil spring, and the boss 315 also adopts a cylindrical structure, which is convenient for assembly with the cylindrical coil spring. Moreover, in general, the cross section of the sealing plug 330 is smaller than the cross section of the inner cavity 320. A gap can be retained between the peripheral side of the sealing plug 330 and the inner cavity 320. When exhausting, the gas inside the battery can flow from the gap to the gas outlet 360 and be discharged.

[0028] In addition to the consideration of assembly convenience, the sealing performance of the assembly of the upper shell 311 and the lower shell 312 must also be taken into consideration. In this embodiment, please continue to refer to Figure 4 The lower shell 312 is provided with a positioning wall 316 around the inner cavity 320, and the upper shell 311 is provided with a positioning groove 317 corresponding to the positioning wall 316. When the upper shell 311 is connected to the lower shell 312, the positioning wall 316 and the positioning groove 317 are engaged. This engaging structure has better bonding and better sealing than plane contact. A joint seam 318 is provided at the engaging part of the positioning wall 316 and the positioning groove 317, and the joint seam 318 is close to the bottom side of the positioning wall 316. The upper shell 311 and the lower shell 312 are assembled by welding, and the position of the joint seam 318 is lower than the top position of the positioning wall 316, which can prevent the electrolyte from flowing back and contaminating the outer shell 310, and keep the exterior of the exhaust device 300 clean.

[0029] Furthermore, Figure 1 , Figure 3 and Figure 4As shown, a liquid injection hole 110 is provided on the cover plate 100, and the air inlet 350 of the exhaust device 300 is connected to the sealing structure through the liquid injection hole 110. The lower shell 312 is sealed and connected to the cover plate 100, and the lower shell 312 completely covers the liquid injection hole 110. After the liquid injection process is completed, the liquid injection hole 110 is sealed by the exhaust device 300, and there is no need to open another hole on the cover plate 100, which reduces the processing process, optimizes the structure of the cover plate 100, and ensures the structural strength of the cover plate 100. It should be noted that the lower shell 312 and the cover plate 100 are sealed by welding. In addition, an explosion-proof valve 120 is provided on the cover plate 100, and the explosion-proof valve 120 and the exhaust device 300 are independent of each other. The exhaust device 300 is mainly used to discharge excess gas inside the battery, while the explosion-proof valve 120 is more used to deal with violent reactions inside the battery, and the two work independently of each other.

[0030] In the description of the present invention, it should be noted that the directions or positional relationships indicated by the terms "front", "rear", "left", "right", "up", "down", "top", "bottom", "inside" and "outside" are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation on the present invention.

[0031] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0032] The protection scope of the present invention is limited only by the claims. Thanks to the teachings of the present invention, those skilled in the art will easily recognize that alternative structures to the structures disclosed in the present invention can be used as feasible alternative embodiments, and the embodiments disclosed in the present invention can be combined to generate new embodiments, which also fall within the scope of the appended claims.

Claims

1. A lithium battery with an exhaust structure, comprising a cover plate (100), a battery cell and a shell (200), wherein the cover plate (100) and the shell (200) are sealed and connected to form a sealed structure, and the battery cell is arranged in the shell (200); an exhaust device (300) is installed on the cover plate (100), characterized in that: The exhaust device (300) comprises an outer shell (310), one end of the outer shell (310) is provided with an air outlet (360), and the other end is provided with an air inlet (350), the air inlet (350) extends into a sealing structure, and the air outlet (360) is connected to the atmosphere; an inner cavity (320) is provided in the outer shell (310), and the inner cavity (320) and the air inlet (350) and the air outlet (360) form an exhaust channel; a sealing plug (330) is movably provided in the inner cavity (320), and the sealing plug (330) blocks the air inlet (350); when exhausting, the sealing plug (330) and the air inlet (350) are separated under air pressure.

2. A lithium battery with an exhaust structure according to claim 1, characterized in that: The outer shell (310) comprises an upper shell (311) and a lower shell (312), and the upper shell (311) and the lower shell (312) are sealed and connected; a groove (313) is provided in the upper shell (311), and an elastic member (340) is provided in the groove (313); the elastic member (340) is fixedly connected to the sealing plug (330), and the elastic member (340) presses the sealing plug (330) and the air inlet (350) tightly.

3. A lithium battery with an exhaust structure according to claim 2, characterized in that: The inner cavity (320) is arranged in the lower shell (312); the bottom inner wall of the inner cavity (320) is provided with a protruding step (314); the air inlet (350) passes through the step (314); the cross section of the step (314) is smaller than the end face of the sealing plug (330).

4. A lithium battery with an exhaust structure according to claim 2, characterized in that: The top wall of the groove (313) is provided with a boss (315), the air outlet (360) passes through the boss (315), one end of the elastic member (340) is connected to the boss (315), and the other end is connected to the sealing plug (330).

5. A lithium battery with an exhaust structure according to claim 1, characterized in that: The cross section of the sealing plug (330) is smaller than the cross section of the inner cavity (320).

6. A lithium battery with an exhaust structure according to claim 2, characterized in that: The lower shell (312) is provided with a positioning wall (316) around the inner cavity (320), and the upper shell (311) is provided with a positioning groove (317) corresponding to the positioning wall (316). When the upper shell (311) and the lower shell (312) are connected, the positioning wall (316) and the positioning groove (317) are engaged.

7. A lithium battery with an exhaust structure according to claim 6, characterized in that: A joint seam (318) is provided at the joint between the positioning wall (316) and the positioning groove (317), and the joint seam (318) is close to the bottom side of the positioning wall (316).

8. A lithium battery with an exhaust structure according to claim 2, characterized in that: The cover plate (100) is provided with a liquid injection hole (110), and the air inlet (350) of the exhaust device (300) passes through the liquid injection hole (110) and is in communication with the sealing structure.

9. A lithium battery with an exhaust structure according to claim 8, characterized in that: The lower shell (312) is sealedly connected to the cover plate (100), and the lower shell (312) completely covers the liquid injection hole (110).

10. A lithium battery with an exhaust structure according to claim 8, characterized in that: An explosion-proof valve (120) is provided on the cover plate (100), and the explosion-proof valve (120) and the exhaust device (300) are independent of each other.

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