Square lithium battery top cover

Abstract

The utility model discloses a square lithium battery top cover, which relates to the technical field of lithium batteries and comprises a top cover sheet, lower plastic cement and an explosion-proof valve, an annular groove is arranged at the bottom of the top cover sheet, an annular boss is arranged at the top of the lower plastic cement, the annular groove on the top cover sheet is clamped with the annular boss on the lower plastic cement, and the explosion-proof valve is arranged on the top cover sheet. Ultrasonic welding is adopted in the position, located on the annular boss, between the top cover piece and the lower plastic, the anti-explosion valve is provided with an anti-explosion valve hole formed in the top cover piece through laser welding, an exhaust fence is arranged at the position, corresponding to the anti-explosion valve, of the lower plastic, and a liquid injection protective cover is arranged at the position, close to the exhaust fence, of the lower plastic. A liquid injection hole is formed in the position, corresponding to the liquid injection protective cover, of the top cover piece. The utility model has the advantages that the lower plastic boss structure arranged on the top cover can prevent free electrolyte from being accumulated near the post terminal to a greater extent, so that the bad influence of corrosion is avoided.

Description

Technical Field

[0001] The utility model relates to the technical field of lithium batteries, in particular to a square lithium battery top cover. Background Art

[0002] As a key component integrating functions, the top cover of new energy lithium battery bears the safety responsibility of the battery. The realization of some functions depends on its components, such as the lower plastic, which is connected with the top cover sheet to form the core body of the top cover. At present, there are some problems with the top cover structure used by relevant manufacturers, among which the more prominent ones are such as timely pressure relief, the impact of electrolyte on the pole piece during injection (because the whole cavity is under negative pressure during injection, and the pressure is relatively high when the electrolyte is injected into the battery), etc. For the specific structure, see Figure 6 shown. Utility Model Content

[0003] In view of the deficiencies in the prior art, the utility model aims to provide a square lithium battery top cover, wherein the lower plastic boss structure provided on the top cover can largely prevent free electrolyte from accumulating near the pole and causing adverse effects of corrosion.

[0004] In order to achieve the above purpose, the technical solution of the utility model is as follows:

[0005] A square lithium battery top cover comprises a top cover sheet, a lower plastic and an explosion-proof valve, wherein an annular groove is provided at the bottom of the top cover sheet, an annular boss is provided at the top of the lower plastic, the annular groove on the top cover sheet is clamped with the annular boss on the lower plastic, ultrasonic welding is adopted at the position of the annular boss between the top cover sheet and the lower plastic, the explosion-proof valve is provided with an explosion-proof valve hole opened on the top cover sheet by laser welding, an exhaust fence is provided at the position corresponding to the explosion-proof valve on the lower plastic, an injection protective cover is provided on the lower plastic near the exhaust fence, and an injection hole is provided on the top cover sheet at the position corresponding to the injection protective cover.

[0006] Preferably, the exhaust grille comprises a crossbeam, a supporting column and a grille unit, the supporting column, the crossbeam and the lower plastic are connected as a whole, and the grille unit is arranged in a frame formed by the crossbeam and the supporting column.

[0007] Preferably, the unit to which the fence belongs is divided into two parts by the plane where the long side of the lower plastic is located, and is radially symmetrical about the plane mirror, and forms an angle of 60° or 120° with the lower surface of the lower plastic.

[0008] Preferably, the distance between the openings toward the explosion-proof valve formed by the two nearest rows of mirror-image adjacent units of the fence is smaller than the openings away from the explosion-proof valve, and the sides of the units to which the fence belongs are vents.

[0009] Preferably, the liquid injection protective cover includes an electrolyte outflow hole and a cavity. The liquid injection protective cover is hemispherical in shape. The liquid injection protective cover is connected to the lower plastic as a whole. A cavity is formed inside the liquid injection protective cover. The liquid injection protective cover is provided with electrolyte outflow holes radiating from the spherical center to the surrounding areas.

[0010] Preferably, the electrolyte outflow holes are arranged in multiple layers, each layer is provided with multiple electrolyte outflow holes, a spacing is left between the electrolyte outflow holes in each layer, and the spacing between each layer decreases from top to bottom.

[0011] Preferably, the aperture size of the electrolyte outflow hole decreases gradually from the lower layer to the upper layer, and the center position of the bottom of the cavity provided with the liquid injection protective cover is solid within a certain radius and no electrolyte outflow hole is provided.

[0012] Preferably, the annular boss includes a first connecting boss and a second connecting boss, the first connecting boss is arranged around the lower plastic and has a trapezoidal shape, with the large surface portion being located on one side of the top cover sheet, and the second connecting boss is arranged on the top of the liquid injection protective cover and has a rectangular shape.

[0013] Preferably, the top cover sheet and the lower plastic are both provided with pole holes for the poles to pass through, a sealing ring is sleeved on the poles, and an upper plastic is provided at the intersection between the poles and the top cover sheet.

[0014] Preferably, a protective film is provided on the explosion-proof valve.

[0015] Compared with the prior art, the beneficial effects of the utility model are:

[0016] 1. The lower plastic boss structure of the top cover can largely prevent the free electrolyte from accumulating near the pole and causing adverse corrosion effects;

[0017] 2. The exhaust grille structure on the top cover can change the flow direction of gas during pressure relief, thereby timely discharging the gas inside the battery to the outside;

[0018] 3. The exhaust grille structure on the top cover can change the flow direction of gas during pressure relief, thereby discharging the gas inside the battery to the outside in time. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The disclosure of the present invention is described with reference to the accompanying drawings. It should be understood that the accompanying drawings are only for illustrative purposes and are not intended to limit the scope of protection of the present invention. In the accompanying drawings, the same reference numerals are used to refer to the same components.

[0020] in:

[0021] Figure 1 This is an exploded view of the top cover of a square lithium battery of the utility model;

[0022] Figure 2 This is a schematic diagram of the structure of the exhaust grille of the utility model;

[0023] Figure 3 It is a top view of the lower plastic of the utility model;

[0024] Figure 4 This is a schematic diagram of the overall structure of the lower plastic of the utility model;

[0025] Figure 5 This is a schematic diagram of the structure of the liquid injection protective cover of the utility model;

[0026] Figure 6 It is a structural schematic diagram of the background technology of the utility model.

[0027] Explanations in the figure: 10, top cover; 11, explosion-proof valve hole; 12, injection hole; 20, lower plastic; 21, exhaust grille; 210, crossbeam; 211, vent hole; 212, supporting column; 213, unit to which the grille belongs; 22, injection protective cover; 221, cavity; 222, electrolyte outflow hole; 25, first connecting boss; 26, second connecting boss; 30, upper plastic; 40, protective film; 41, explosion-proof valve; 50, sealing ring; 60, pole. DETAILED DESCRIPTION

[0028] It is easy to understand that according to the technical solution of the utility model, without changing the essential spirit of the utility model, a person skilled in the art can propose a variety of interchangeable structural modes and implementation modes. Therefore, the following specific implementation modes and drawings are only exemplary descriptions of the technical solution of the utility model, and should not be regarded as the entirety of the utility model or as a limitation or restriction to the technical solution of the utility model.

[0029] like Figure 1 As shown, as a square lithium battery top cover of the utility model, it includes a top cover sheet 10, a lower plastic 20 and an explosion-proof valve 41. The top cover sheet 10 is provided with an annular groove at the bottom, and the lower plastic 20 is provided with an annular boss at the top. The annular groove on the top cover sheet 10 is clamped with the annular boss on the lower plastic. Ultrasonic welding is adopted at the position of the annular boss between the top cover sheet 10 and the lower plastic 20. The explosion-proof valve 41 is provided with an explosion-proof valve hole 11 opened on the top cover sheet 10 by laser welding. A protective film 40 is provided on the explosion-proof valve 41. An exhaust fence 21 is provided on the lower plastic 20 at a position corresponding to the explosion-proof valve 41. A liquid injection protective cover 22 is provided on the lower plastic 20 near the exhaust fence 21. An injection hole 12 is provided on the top cover sheet 10 at a position corresponding to the injection protective cover 22.

[0030] The top cover sheet 10 and the lower plastic 20 are both provided with pole holes for the pole 60 to pass through, a sealing ring 50 is sleeved on the pole 60 , and an upper plastic 30 is provided at the intersection between the pole 60 and the top cover sheet 10 .

[0031] The pole 60 and the sealing ring 50 are sleeved and penetrated from the pole hole corresponding to the lower plastic 20. The lower plastic 20 and the top cover sheet 10 are inserted into the corresponding groove of the top cover sheet 10 through the annular boss on the lower plastic 20, and then ultrasonic welding is performed at the position of the annular boss to fix them. Finally, injection molding is performed at the pole 60 to form the upper plastic 30. The explosion-proof valve 41 is installed at the corresponding explosion-proof valve hole 11 for laser welding, and the protective film 40 is affixed to complete the entire top cover assembly.

[0032] like Figure 2 As shown, the exhaust grille 21 includes a crossbeam 210, a supporting column 212 and a grille unit 213. The supporting column 212, the crossbeam 210 and the lower plastic 20 are connected as a whole. The grille unit 213 is provided in the frame formed by the crossbeam 210 and the supporting column 212.

[0033] The fence unit 213 is divided into two parts by the plane where the long side of the lower plastic 20 is located, and is radially symmetrical about the plane mirror, and forms an angle of 60° or 120° with the lower surface of the lower plastic 20 .

[0034] The exhaust grille 21 is composed of a crossbeam 210, a supporting column 212, a vent 211 and a grille unit 213. The exhaust grille 21 is arranged at the geometric center of the top cover and cooperates with the explosion-proof valve hole 11. The overall outline of the grille 21 is a rectangle. The supporting column 212 and the crossbeam 210 are connected to the lower plastic 20 body as a whole. The grille units 213 are evenly arranged at the geometric center of the lower plastic 20. The grille units 213 are divided into two parts by the plane where the long side of the lower plastic 20 is located, and are mirror-symmetrical about the plane. The angle formed with the lower surface of the lower plastic 20 (the coordinate direction is upward) is 60° or 120°, wherein the distance between the two exhaust grille units 213 that are mirror-adjacent and closest to each other is smaller than the opening facing away from the explosion-proof valve. The sides of the grille units 213 are vents 211, which are several in number and symmetrically distributed.

[0035] The distance between the openings toward the explosion-proof valve 41 formed by the two mirror-image adjacent rows of fence units 213 is smaller than the openings away from the explosion-proof valve 41 , and the sides of the fence units 213 are vents 211 .

[0036] The liquid injection protective cover 22 includes an electrolyte outflow hole 222 and a cavity 221. The liquid injection protective cover 22 is hemispherical in shape. The liquid injection protective cover 22 is connected to the lower plastic 20 as a whole. A cavity 221 is formed inside the liquid injection protective cover 22. The liquid injection protective cover 22 is provided with electrolyte outflow holes 222 radiating from the center of the sphere to the surrounding areas.

[0037] The electrolyte outflow holes 222 are arranged in multiple layers, and each layer is provided with a plurality of electrolyte outflow holes 222 . There is a spacing between the electrolyte outflow holes 222 in each layer, and the spacing between each layer decreases from top to bottom.

[0038] The aperture size of the electrolyte outflow hole 222 decreases gradually from the lower layer to the upper layer, and the bottom center position of the cavity 221 provided in the liquid injection protective cover 22 is solid within a certain radius and no electrolyte outflow hole 222 is provided.

[0039] The liquid injection protective cover 22 is composed of an electrolyte outflow hole 222 and a cavity 221. The liquid injection protective cover 22 is hemispherical in shape and is connected to the lower plastic body 20 as a whole. The interior of the hemispherical body is a cavity 221 with a certain wall thickness and is provided with a plurality of electrolyte outflow holes 222. The electrolyte outflow holes 222 are arranged in a hemispherical manner and radiate around the center of the sphere. Each layer is provided with a plurality of electrolyte outflow holes 222, and the electrolyte outflow holes 222 between layers have a certain spacing, and the spacing is smaller as it goes down. The aperture size of the electrolyte outflow hole 222 gradually decreases from the lower layer to the upper layer. The cavity 221 provided in the liquid injection protective cover 22 is solid within a certain radius at the center of the bottom and no electrolyte outflow hole 222 is provided. In the cross section, it can be seen from top to bottom that the heights of each electrolyte outflow hole 222 are different, and the aperture of the electrolyte outflow hole 222 at the bottom is the largest.

[0040] like Figure 3-5 As shown, the annular boss includes a first connecting boss 25 and a second connecting boss 26. The first connecting boss 25 is arranged around the lower plastic 20 and has a trapezoidal shape. The large surface portion is located on one side of the top cover sheet 10. The second connecting boss 26 is arranged on the top of the liquid injection protective cover 22 and has a rectangular shape.

[0041] The first connecting boss 25 and the second connecting boss 26 are connecting bridges between the lower plastic 20 and the top cover sheet 10. The first connecting boss 25 is arranged in a circle around the lower plastic 20 and has a trapezoidal shape. The portion connected to the top cover sheet 10 is larger in size and is used for ultrasonic welding and melting. The second connecting boss 26 is arranged on the top of the liquid injection protective cover 22 and has a rectangular shape for limiting.

[0042] When the battery is injected with liquid, due to the negative pressure, the pole piece or diaphragm will move upward during the injection. Under the obstruction of the bottom of the cavity 221 provided in the injection protective cover 22, the pole piece or diaphragm will not continue to move upward, thereby smoothly realizing the injection process; when the electrolyte leaves the injection machine and enters the injection protective cover 22, the electrolyte will fall onto the pole piece from different electrolyte outflow holes 222. Since the bottom of the cavity 221 is a solid part without a hole, it is avoided that the electrolyte with a large pressure is directly sprayed onto the pole piece. The designed electrolyte outflow holes 222 have different heights, so that the electrolyte injected at a large pressure at the beginning can be buffered and diverted on the protective cover 22, thereby reducing the pressure of the injected electrolyte;

[0043] Since the aperture of the electrolyte outflow hole 222 at the bottom is larger than that at the upper layer, the electrolyte can quickly fall into the battery, so the electrolyte in the liquid injection protective cover 22 will not overflow;

[0044] The electrolyte falls gently on the electrode, which greatly reduces the damage to the electrode caused by injection. When the battery has thermal runaway and the explosion-proof valve 41 opens, the gas inside the battery will flow to the upper part of the battery. At this time, a large amount of gas inside the battery needs to be discharged in time. In the process of all the gas rushing upward, since the exhaust fence 21 is provided with a fence unit 213, the gas will change its flow direction after passing through here, so that the gas rushing to other parts will directly flow to the explosion-proof valve hole 11, thereby achieving the effect of timely exhaust.

[0045] Because the lower plastic 20 is provided, the structure is ultrasonically welded to the top cover sheet 10. During the use of the battery, the free electrolyte will be blocked outside by the boundary and will not enter the pole and accumulate at this position to cause a certain degree of corrosion to the pole. Similarly, the second connecting boss 26 provided on the liquid injection protective cover 22 can prevent the residual electrolyte from seeping into the vicinity of the pole during liquid injection.

[0046] The technical scope of the present invention is not limited to the contents described above. Those skilled in the art can make various deformations and modifications to the above embodiments without departing from the technical concept of the present invention, and these deformations and modifications should all fall within the protection scope of the present invention.

Claims

1. A square lithium battery top cover, characterized in that: The invention comprises a top cover sheet (10), a lower plastic (20) and an explosion-proof valve (41), wherein an annular groove is provided at the bottom of the top cover sheet (10), an annular boss is provided at the top of the lower plastic (20), the annular groove on the top cover sheet (10) is clamped with the annular boss on the lower plastic, ultrasonic welding is adopted at the position of the annular boss between the top cover sheet (10) and the lower plastic (20), an explosion-proof valve hole (11) is provided on the top cover sheet (10) by laser welding, an exhaust grille (21) is provided on the lower plastic (20) at a position corresponding to the explosion-proof valve (41), an injection protective cover (22) is provided on the lower plastic (20) at a position close to the exhaust grille (21), and an injection hole (12) is provided on the top cover sheet (10) at a position corresponding to the injection protective cover (22).

2. A square lithium battery top cover according to claim 1, characterized in that: The exhaust grille (21) comprises a crossbeam (210), a supporting column (212) and a grille unit (213); the supporting column (212), the crossbeam (210) and the lower plastic (20) are connected as a whole; and the grille unit (213) is arranged in a frame formed by the crossbeam (210) and the supporting column (212).

3. A square lithium battery top cover according to claim 2, characterized in that: The unit (213) to which the fence belongs is divided into two parts by the plane where the long side of the lower plastic (20) is located, and is radially symmetrical about the plane mirror, and forms an angle of 60° or 120° with the lower surface of the lower plastic (20).

4. A square lithium battery top cover according to claim 2, characterized in that: The distance between the two mirror-image adjacent rows of the fence units (213) is smaller than the distance between the openings facing the explosion-proof valve (41) and the openings facing away from the explosion-proof valve (41), and the sides of the fence units (213) are vents (211).

5. The square lithium battery top cover according to claim 1, characterized in that: The liquid injection protective cover (22) comprises an electrolyte outflow hole (222) and a cavity (221); the liquid injection protective cover (22) is hemispherical in shape; the liquid injection protective cover (22) is connected to the lower plastic (20) as a whole; a cavity (221) is formed inside the liquid injection protective cover (22); and the liquid injection protective cover (22) is provided with electrolyte outflow holes (222) radiating from the center of the sphere to the surrounding areas.

6. A square lithium battery top cover according to claim 5, characterized in that: The electrolyte outflow holes (222) are arranged in multiple layers, each layer is provided with a plurality of electrolyte outflow holes (222), a spacing is left between the electrolyte outflow holes (222) in each layer, and the spacing between each layer decreases from top to bottom.

7. A square lithium battery top cover according to claim 6, characterized in that: The aperture size of the electrolyte outflow hole (222) gradually decreases from the lower layer to the upper layer, and the bottom center position of the cavity (221) provided in the liquid injection protection cover (22) is solid within a certain radius and is not provided with an electrolyte outflow hole (222).

8. The square lithium battery top cover according to claim 7, characterized in that: The annular boss comprises a first connecting boss (25) and a second connecting boss (26); the first connecting boss (25) is arranged around the lower plastic (20) in a circle and is in a trapezoidal shape, with a large surface portion located on one side of the top cover sheet (10); the second connecting boss (26) is arranged on the top of the liquid injection protective cover (22) and is in a rectangular shape.

9. The square lithium battery top cover according to claim 1, characterized in that: The top cover sheet (10) and the lower plastic (20) are both provided with pole holes for the pole (60) to pass through, a sealing ring (50) is sleeved on the pole (60), and an upper plastic (30) is provided at the intersection between the pole (60) and the top cover sheet (10).

10. The square lithium battery top cover according to claim 1, characterized in that: The explosion-proof valve (41) is provided with a protective film (40).

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