Cell top cap

Abstract

The present invention relates to the technical field of energy storage cells. Disclosed is a cell top cap. A lower plastic structure (10) of the cell top cap comprises a first plate body (110), a second plate body (120), and a middle protrusion (130) located between the first plate body (110) and the second plate body (120), wherein the middle protrusion (130) protrudes relative to the bottom side of the first plate body (110) and the bottom side of the second plate body (120); a first terminal through hole (111) is provided in the first plate body (110); a first liquid injection through hole (121) and a second terminal through hole (122) are provided in the second plate body (120); and a blocking portion (140) protruding from the peripheral side of the first liquid injection through hole (121) is provided on the bottom side of the second plate body (120), the blocking portion (140) is of a hollowed-out structure, and the area of the hollowed-out area of the blocking portion (140) is larger than the cross-sectional area of the first liquid injection through hole (121). The lower plastic structure (10) of the cell top cap can increase the liquid injection speed, can avoid the problem of liquid leakage, and can also reduce the intensity of an electrolyte scouring the inside of a cell when the electrolyte is injected. Moreover, providing the middle protrusion (130) can improve the overall strength of the lower plastic structure (10).

Description

Battery cell cover

[0001] Cross-references

[0002] This application claims priority to Chinese patent application number 2023111258482, filed on September 1, 2023, entitled “A battery cell top cover”, and filed on September 1, 2023, and priority to Chinese patent application number 2023111265128, filed on September 1, 2023, entitled “Lower plastic structure of battery cell top cover and battery cell top cover”, and filed on September 1, 2023, and priority to Chinese patent application number 2023223848895, filed on September 1, 2023, all of which are incorporated herein by reference. Technical Field

[0003] The present application relates to the technical field of energy storage cells, and in particular to a cell top cover. Background Art

[0004] The top cover of the energy storage battery cell currently on the market includes structures such as poles, plain aluminum sheets, and lower plastic. A through hole is provided at the same height of the plain aluminum sheet and the lower plastic to form an injection hole, and a sealing nail is provided on the injection hole. The shape of the existing injection hole is a straight cylinder. After the electrolyte is injected into the battery cell, the injection speed of the injection hole is slow and the injection time is long. In addition, the interior of the battery cell needs to be vacuumed and exhausted before injection to form a negative pressure inside the battery cell. After the injection is completed and the sealing nail is installed at the injection hole, the sealing nail is easily pressed into the interior of the battery cell due to the negative pressure, thereby affecting the sealing performance at the injection hole, causing the electrolyte to flow out of the injection hole, causing serious leakage problems.

[0005] Therefore, the lower plastic structure of the battery cell top cover in the prior art has the problems of slow liquid injection speed and easy leakage.

[0006] Summary of the Invention

[0007] The purpose of the embodiments of the present application is to provide a battery cell top cover to increase the injection speed thereof, avoid leakage problems, and reduce the scouring intensity of the electrolyte on the inside of the battery cell during injection.

[0008] In order to solve the above technical problems, the implementation method of the embodiment of the present application provides a battery cell top cover, including a plain aluminum sheet; a lower plastic structure, and the top side of the lower plastic structure is arranged on the bottom side of the plain aluminum sheet; wherein the lower plastic structure includes a first plate body, a second plate body and an intermediate protrusion located between the first plate body and the second plate body, and the intermediate protrusion is protruded relative to the bottom side of the first plate body and the bottom side of the second plate body; a first pole through hole is provided on the first plate body; a first liquid injection through hole and a second pole through hole are provided on the second plate body; and a stop portion protruding from the circumferential side of the first liquid injection through hole is provided on the bottom side of the second plate body, and the stop portion is a hollow structure, and the area of ​​the hollow region of the stop portion is larger than the cross-sectional area of ​​the first liquid injection through hole.

[0009] In some embodiments, the stopper includes a side surface and a bottom surface. The side surface is connected to the bottom side of the second plate body and surrounds the periphery of the first liquid injection hole. The side surface extends away from the second plate body and connects to the bottom surface. The side surface is evenly spaced along its circumference, and the total area of ​​all diversion holes is greater than the cross-sectional area of ​​the first liquid injection hole. In this way, the bottom surface acts as a good stop for the sealing pin, and the multiple diversion holes on the side surface allow the electrolyte injected through the first liquid injection hole to quickly flow out in a divergent manner along the side of the stopper, thereby increasing the injection speed of the first liquid injection hole.

[0010] In some embodiments, the first and second plates are each provided with side protrusions on opposite sides thereof. The side protrusions protrude from the bottom sides of the first and second plates, and are provided with a plurality of holes. Thus, the side protrusions form an embedded space between the side protrusions and the first and second plates, respectively, facilitating the embedding of the winding core of the battery cell structure on the bottom side of the lower plastic structure, thereby facilitating the installation of the battery cell cover and the battery cell structure disposed on the bottom side of the battery cell cover. The multiple holes on the side protrusions can reduce the weight of the lower plastic structure, thereby reducing the weight of the battery cell cover.

[0011] In some embodiments, the side protrusions are frame-shaped, and a plurality of reinforcing ribs extending along the length of the lower plastic structure are disposed within the side protrusions. Thus, the frame-shaped side protrusions can further reduce the weight of the lower plastic structure, while the reinforcing ribs can enhance the strength of the lower plastic structure.

[0012] In some embodiments, a sealing pin is further included, and a second liquid injection hole having the same central axis as the first liquid injection hole is provided on the plain aluminum sheet; the sealing pin is inserted into the second liquid injection hole, and the gap between the bottom end of the sealing pin and the bottom of the stop portion is set at 0.5mm-2mm.

[0013] In some embodiments, the second liquid injection through hole is a stepped hole including a first hole segment and a second hole segment, the radial dimension of the first hole segment is larger than the radial dimension of the second hole segment, and the second hole segment is closer to the first liquid injection through hole.

[0014] In some embodiments, an explosion-proof valve is further included. A plurality of vent holes are provided on the middle protrusion. The explosion-proof valve is installed on the back side of the middle protrusion and is arranged opposite to the plurality of vent holes.

[0015] In some embodiments, a card slot is provided on both sides of the middle protrusion connecting the first plate body and the second plate body, the explosion-proof valve is inserted into the card slot, and the recessed depth of the card slot is smaller than the protruding height of the middle protrusion.

[0016] In some embodiments, the middle protrusion is rectangular, the ventilation holes are strip-shaped and extend along the width direction of the lower plastic structure; and a plurality of the ventilation holes are evenly arranged on the middle protrusion at intervals.

[0017] In some embodiments, the bare aluminum sheet has a positive pole through hole, a negative pole through hole and an explosion-proof through hole that penetrate the thickness of the bare aluminum sheet, and the positive pole through hole and the negative pole through hole are respectively located at two different positions of the explosion-proof through hole; it also includes: an explosion-proof valve, the explosion-proof valve has a relative upper surface and a lower surface, the explosion-proof valve is fixed on the bare aluminum sheet to cover the explosion-proof through hole, and the upper surface faces the explosion-proof through hole; wherein, the explosion-proof valve includes a bursting mark and a reinforcing rib, the bursting mark is a pit recessed from the upper surface toward the lower surface, the reinforcing rib is located in a partial area of ​​the pit, and the distance between the reinforcing rib and the negative pole through hole is smaller than the distance between the reinforcing rib and the positive pole through hole.

[0018] In some embodiments, the thickness of the blasting score ranges from 0.1 mm to 0.15 mm.

[0019] In some embodiments, the thickness of the reinforcing rib is greater than the thickness of the blasting score.

[0020] In some embodiments, the thickness of the reinforcing rib ranges from 0.16 mm to 0.25 mm.

[0021] In some embodiments, the expanded length of the reinforcement rib is less than or equal to one sixth of the expanded length of the blasting score.

[0022] In some embodiments, the explosion-proof valve further includes an installation mark, the installation mark is located on the lower surface, and the installation mark is arranged adjacent to the reinforcing rib.

[0023] In some embodiments, the explosion-proof valve also includes a connecting portion, which includes: a first outer ring portion, which is arranged around the outer periphery of the bursting score and is connected to the bursting score; a second outer ring portion, which is arranged around the outer periphery of the first outer ring portion and is connected to the first outer ring portion; wherein the thickness of the first outer ring portion is less than or equal to the thickness of the second outer ring portion.

[0024] In some embodiments, the thickness of the second outer ring portion ranges from 0.3 mm to 0.7 mm.

[0025] In some embodiments, the explosion-proof valve further includes a bursting disc, wherein the bursting disc is connected to the inner periphery of the bursting score, and the bursting score is arranged around the outer periphery of the bursting disc.

[0026] In some embodiments, the reinforcing rib and the bursting disc are an integrally formed structure.

[0027] In the battery cell top cover of the embodiment of the present application, since the bottom side of the first liquid injection through hole of the lower plastic structure is provided with a hollow stopper, after the electrolyte is injected into the first liquid injection through hole, the stopper can divide the electrolyte into multiple beams and inject them into the battery cell in different directions, thereby greatly reducing the obstruction of the electrolyte by the inner wall of the battery cell, thereby increasing the injection speed of the first liquid injection through hole and shortening its injection time; and the stopper can act as a stopper for the sealing nail, thereby avoiding the sealing nail being pressed into the battery cell due to negative pressure, causing sealing problems, thereby avoiding leakage problems at the first liquid injection through hole; therefore, the lower plastic structure of the battery cell top cover can increase the injection speed and avoid leakage problems. In addition, since the stopper divides the electrolyte into multiple beams, the scouring intensity of each beam of electrolyte on the electrode inside the battery cell when it is injected into the battery cell is relatively low, thereby avoiding the peeling problem caused by the electrode material (positive electrode material or negative electrode material) on the electrode sheet being scour by the electrolyte, thereby allowing the electrode sheet to maintain good conductive performance.

[0028] The cell top cover can also include a sealing pin. The bare aluminum sheet is provided with a second liquid injection hole coaxial with the first liquid injection hole. The sealing pin is inserted into the second liquid injection hole, and the gap between the bottom end of the sealing pin and the bottom of the stopper is set to 0.5mm-2mm. Because the bare aluminum sheet is positioned on top of the lower plastic structure, providing the second liquid injection hole directly above the first liquid injection hole helps speed up electrolyte injection.

[0029] Furthermore, the second injection hole is a stepped hole comprising a first hole segment and a second hole segment. The radial dimension of the first hole segment is larger than that of the second hole segment, and the second hole segment is closer to the first injection hole. This stepped second injection hole also serves as a stop for the sealing pin, further ensuring the sealing of the injection hole.

[0030] The cell cover also includes an explosion-proof valve. The central protrusion is provided with multiple vent holes. The explosion-proof valve is mounted on the back of the central protrusion, facing the vent holes. The central protrusion protrudes downward relative to the explosion-proof valve, ensuring sufficient airflow between the lower plastic structure and the explosion-proof valve. The vent holes on the central protrusion not only provide airflow but also filter the rupture disc of the explosion-proof valve when it explodes, preventing it from falling into the cell structure on the bottom side of the lower plastic structure.

[0031] In addition, the middle protrusion is provided with a slot on each side where it connects the first and second plates. The explosion-proof valve is inserted into the slot, and the depth of the slot is less than the protruding height of the middle protrusion. This allows the explosion-proof valve to be mounted on the back of the middle protrusion with a simple structure, further simplifying the mounting structure between the explosion-proof valve and the middle protrusion.

[0032] Furthermore, the central protrusion is rectangular, and the vents are strip-shaped and extend along the width of the lower plastic structure. Furthermore, multiple vents are evenly spaced and spaced apart on the central protrusion. This arrangement ensures sufficient exhaust area at the explosion-proof valve, allowing the central protrusion to better guide air. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] One or more embodiments are exemplarily illustrated by pictures in the corresponding drawings. These exemplifications do not constitute limitations on the embodiments. Elements with the same reference numerals in the drawings are represented as similar elements. Unless otherwise stated, the figures in the drawings do not constitute proportional limitations.

[0034] FIG1 is a schematic structural diagram of a lower plastic structure of a battery cell top cover according to some embodiments of the present application;

[0035] FIG2 is a schematic top view of the lower plastic structure of the battery cell top cover according to some embodiments of the present application;

[0036] FIG3 is a schematic cross-sectional view of the structure of FIG1 ;

[0037] FIG4 is a schematic cross-sectional view of the lower plastic structure and the bare aluminum sheet of the battery cell top cover according to some embodiments of the present application;

[0038] FIG5 is an exploded view of a battery cell top cover according to some embodiments of the present application;

[0039] FIG6 is an assembly diagram of a battery cell top cover according to some embodiments of the present application;

[0040] FIG7 is a schematic diagram of the assembled structure of a cell top cover provided in some embodiments of the present application;

[0041] FIG8 is a three-dimensional half-section view of a smooth aluminum sheet provided in some embodiments of the present application;

[0042] FIG9 is a schematic structural diagram of an explosion-proof valve provided in some embodiments of the present application;

[0043] FIG10 is a schematic structural diagram of another explosion-proof valve provided in some embodiments of the present application;

[0044] FIG11 is a schematic structural diagram of another explosion-proof valve provided in some embodiments of the present application;

[0045] FIG12 is a schematic structural diagram of another explosion-proof valve provided in some embodiments of the present application;

[0046] FIG13 is a front view schematic diagram of another explosion-proof valve provided in some embodiments of the present application;

[0047] FIG14 is a schematic structural diagram of another explosion-proof valve provided in some embodiments of the present application;

[0048] FIG15 is a schematic structural diagram of another explosion-proof valve provided in some embodiments of the present application;

[0049] FIG16 is a front view schematic diagram of another explosion-proof valve provided in some embodiments of the present application;

[0050] FIG17 is a schematic diagram of the combined structure of another battery cell top cover provided in some embodiments of the present application;

[0051] FIG18 is a perspective view of the structure of a protective sheet provided in some embodiments of the present application;

[0052] FIG19 is a perspective view of the structure of a gasket provided in some embodiments of the present application;

[0053] FIG20 is a schematic structural diagram of a protective sheet body provided in some embodiments of the present application;

[0054] FIG21 is a schematic diagram of an explosion structure provided by some embodiments of the present application;

[0055] FIG22 is an assembly structure diagram of a battery cell top cover and a battery cell shell provided in some embodiments of the present application. DETAILED DESCRIPTION

[0056] To make the purpose, technical solutions, and advantages of the embodiments of the present application clearer, each embodiment of the embodiments of the present application will be described in detail below with reference to the accompanying drawings. However, it will be understood by those skilled in the art that many technical details are provided in each embodiment of the embodiments of the present application to help readers better understand the present application. However, even without these technical details and various changes and modifications based on the following embodiments, the technical solutions claimed in the present application can be implemented.

[0057] In the embodiments of the present application, terms such as "upper," "lower," "left," "right," "front," "back," "top," "bottom," "inner," "outer," "center," "vertical," "horizontal," "transverse," and "longitudinal" indicate positions or locations based on the positions or locations shown in the accompanying drawings. These terms are primarily intended to better describe the embodiments of the present application and their implementation methods, and are not intended to limit the devices, elements, or components indicated to having a specific orientation, or to being constructed or operated in a specific orientation.

[0058] Furthermore, some of the above terms may be used to express other meanings besides indicating a direction or position relationship. For example, the term "on" may also be used to indicate a certain dependency or connection relationship in certain circumstances. Those skilled in the art will understand the specific meanings of these terms in the embodiments of this application based on the specific circumstances.

[0059] Furthermore, the terms "installed," "set," "provided with," "opened," "connected," and "connected" should be interpreted broadly. For example, they can refer to fixed connections, removable connections, or integral structures; mechanical connections or electrical connections; direct connections, indirect connections through an intermediary, or internal communication between two devices, elements, or components. Those skilled in the art will understand the specific meanings of these terms in the embodiments of this application based on the specific circumstances.

[0060] Furthermore, the terms "first," "second," and the like are primarily used to distinguish between different devices, elements, or components (which may or may not be of the same type and configuration), and are not intended to indicate or imply the relative importance or quantity of the devices, elements, or components indicated. Unless otherwise specified, "plurality" means two or more.

[0061] An implementation of an embodiment of the present application provides a lower plastic structure of a battery cell top cover, see Figures 1 to 3, including a first plate body 110, a second plate body 120 and a middle protrusion 130 located between the first plate body 110 and the second plate body 120, and the middle protrusion 130 is protruded relative to the bottom side of the first plate body 110 and the bottom side of the second plate body 120; a first pole through hole 111 is provided on the first plate body 110; a first liquid injection through hole 121 and a second pole through hole 122 are provided on the second plate body 120; and a stopper 140 protruding from the peripheral side of the first liquid injection through hole 121 is provided on the bottom side of the second plate body 120, the stopper 140 is a hollow structure, and the area of ​​the hollow region of the stopper 140 is larger than the cross-sectional area of ​​the first liquid injection through hole 121.

[0062] In the embodiment of the present application, the electrolyte of the battery cell is injected into the battery cell from the first injection hole 121. Since a hollow stopper 140 is provided on the bottom side of the first injection hole 121, the electrolyte enters the first injection hole 121 and is injected into the battery cell in a divergent manner through the hollow area of ​​the stopper 140. Therefore, the stopper 140 can change the flow direction of the electrolyte injected into the battery cell through the first injection hole 121, and can divide the electrolyte into multiple beams and inject them into the battery cell in different directions, so as to greatly reduce the obstruction of the inner wall of the battery cell to the electrolyte, thereby increasing the injection speed of the first injection hole 121 and shortening its injection time; the area of ​​the hollow area of ​​the stopper 140 is larger than that of the first injection hole 121. 21, so as to ensure that the electrolyte injected through the first liquid injection hole 121 can flow out of the stopper 140 in time, and avoid the stopper 140 blocking the electrolyte injected into the first liquid injection hole 121, thereby avoiding the stopper 140 from affecting the injection speed; and after the injection is completed, the first liquid injection hole 121 needs to be sealed by the sealing pin 30, and the interior of the battery cell is under negative pressure, and the stopper 140 can stop the sealing pin 30, so as to avoid the sealing pin 30 being pressed into the interior of the battery cell due to the negative pressure, causing sealing problems, thereby avoiding leakage problems at the first liquid injection hole 121; therefore, the lower plastic structure of the battery cell top cover can increase the injection speed and avoid leakage problems. In addition, the setting of the middle protrusion 130 can increase the overall strength of the lower plastic structure 10.

[0063] Specifically, the stopper 140 includes a side surface 141 and a bottom surface 142. The side surface 141 is connected to the bottom side of the second plate 120 and surrounds the periphery of the first liquid injection hole 121. The side surface 141 extends away from the second plate 120 and connects to the bottom surface 142. A plurality of diverter holes 1411 are evenly spaced along the circumference of the side surface 141, and the combined area of ​​all diverter holes 1411 is greater than the cross-sectional area of ​​the first liquid injection hole 121. Thus, the bottom surface 142 effectively stops the sealing pin 30. The multiple diverter holes 1411 on the side surface 141 allow the electrolyte injected through the first liquid injection hole 121 to quickly flow out in a divergent manner along the periphery of the stopper 140, thereby increasing the injection speed of the first liquid injection hole 121.

[0064] More specifically, the stopper 140 can be bowl-shaped, barrel-shaped, or similar, with a thickness of approximately 0.8 mm, preferably 0.8 mm. The diverter hole 1411 can be trapezoidal, rectangular, triangular, or similar, depending on the shape of the side surface 141. In this embodiment, the stopper 140 is bowl-shaped, and the diverter hole 1411 is a trapezoidal hole. Furthermore, a through hole can also be provided on the bottom surface 142 of the stopper 140, and the radial dimension of the through hole must be smaller than the minimum radial dimension of the sealing pin 30.

[0065] The first plate 110, the second plate 120, and the middle protrusion 130, as well as the stopper 140 and the second plate 120, can be connected by bonding, snapping, or the like, or can be integrally formed. The specific configuration can be determined based on actual design and usage requirements, and this embodiment does not impose any specific limitations thereto. Furthermore, the first pole through-hole 111 and the second pole through-hole 122 are used for the positive pole 50 and the negative pole 60 to pass through the lower plastic structure 10, respectively. The first liquid injection through-hole 121 can also be provided on the first plate 110. In this case, the stopper 140 is provided on the bottom side of the first plate 110 and protrudes from the peripheral side of the first liquid injection through-hole 121 in a direction away from the first plate 110.

[0066] Furthermore, side protrusions 150 are provided on opposite sides of the first and second plates 110, 120. These protrusions 150 protrude from the bottom of the first and second plates 110, 120, and are provided with a plurality of holes 151. Thus, an embedded space is formed between the side protrusions 150 and the first and second plates 110, 120, respectively, facilitating the embedding of the winding core of the battery cell structure on the bottom side of the lower plastic structure 10, thereby facilitating the installation of the battery cell cover and the battery cell structure disposed on the bottom side of the battery cell cover. The plurality of holes 151 on the side protrusions 150 can reduce the weight of the lower plastic structure 10, and thereby reduce the weight of the battery cell cover.

[0067] Specifically, the side protrusion 150 has a frame structure, and a plurality of reinforcing ribs 152 are disposed within the side protrusion 150 and extend along the length direction X of the lower plastic structure 10. Thus, the frame structure of the side protrusion 150 can further reduce the weight of the lower plastic structure 10, while the provision of the reinforcing ribs 152 can enhance the strength of the lower plastic structure 10.

[0068] More specifically, the number of holes 151 and reinforcement ribs 152 on the side end protrusion 150 can be two, three, four, etc., respectively, and the number of holes 151 is greater than the number of reinforcement ribs 152. The specific number can be set according to actual needs and is not specifically limited in this embodiment.

[0069] The implementation method of the embodiment of the present application also provides a battery cell top cover, see Figures 4-6, including a plain aluminum sheet 20, and also includes a lower plastic structure of any of the above-mentioned battery cell top covers, the top side of the lower plastic structure 10 is arranged on the bottom side of the plain aluminum sheet 20, and a sealing ring 70 is arranged between the lower plastic structure 10 and the plain aluminum sheet 20, and the sealing ring 70 is sleeved on the pole.

[0070] In the battery cell top cover of the embodiment of the present application, since a hollow stopper 140 is provided on the bottom side of the first liquid injection hole 121 of the lower plastic structure 10, after the electrolyte is injected into the first liquid injection hole 121, the stopper 140 can divide the electrolyte into multiple beams and inject them into the battery cell in different directions, so as to greatly reduce the obstruction of the inner wall of the battery cell to the electrolyte, thereby increasing the injection speed of the first liquid injection hole 121 and shortening its injection time; and the stopper 140 can act as a stopper for the sealing nail 30, so as to avoid the sealing nail 30 being pressed into the battery cell due to negative pressure and causing sealing problems, thereby avoiding leakage problems at the first liquid injection hole 121; therefore, the lower plastic structure of the battery cell top cover can increase the injection speed and avoid leakage problems.

[0071] In addition, in the related art, the injection hole is generally a straight cylindrical injection hole. When the electrolyte is injected into the battery cell through the straight cylindrical injection hole, it will scour the electrode in the battery cell with great intensity, thereby causing the positive electrode material or negative electrode material on the electrode to have a risk of peeling off. In the embodiment of the present disclosure, the stopper 140 can divide the electrolyte into multiple beams and inject them into the battery cell from different directions. While increasing the injection speed, because the electrolyte is divided into multiple beams, the scouring intensity of the electrode in the battery cell when the electrolyte is injected into the battery cell is relatively weak, thereby reducing the risk of the positive electrode material or negative electrode material being peeled off due to the strong scouring of the electrode liquid on the electrode, thereby ensuring that the electrode in the battery cell still maintains good performance after the electrode liquid is injected into the battery cell.

[0072] Furthermore, the cell top cover includes a sealing pin 30. The bare aluminum sheet 20 is provided with a second liquid injection hole 210 having the same central axis as the first liquid injection hole 121. The sealing pin 30 is inserted into the second liquid injection hole 210, and the gap between the bottom end of the sealing pin 30 and the bottom of the stopper 140 is set to 0.5mm-2mm. For example, it can be 0.5mm, 0.9mm, 1.6mm, 2mm, etc. Thus, since the bare aluminum sheet 20 is disposed on the top side of the lower plastic structure 10, the second liquid injection hole 210 directly above the first liquid injection hole 121 helps to speed up the injection of electrolyte.

[0073] Specifically, the second liquid injection hole 210 is a stepped hole comprising a first hole section 211 and a second hole section 212. The radial dimension of the first hole section 211 is larger than that of the second hole section 212, and the second hole section 212 is closer to the first liquid injection hole 121. Thus, the stepped second liquid injection hole 210 can also serve as a stop for the sealing pin 30, thereby further ensuring the sealing of the liquid injection hole.

[0074] The bare aluminum sheet 20 is also provided with a third pole through hole 220 and a fourth pole through hole 230 which have the same central axis as the first pole through hole 111 and the second pole through hole 122 respectively. The positive pole 50 extends to the outside of the battery cell top cover through the first pole through hole 111 and the third pole through hole 220 in sequence, and the negative pole 60 extends to the outside of the battery cell top cover through the second pole through hole 122 and the fourth pole through hole 230 in sequence.

[0075] Furthermore, the cell top cover includes an explosion-proof valve 40. A plurality of vent holes 131 are provided on the central protrusion 130. The explosion-proof valve 40 is mounted on the back of the central protrusion 130 and is positioned opposite the vent holes 131. Thus, the central protrusion 130 protrudes downward relative to the explosion-proof valve 40, ensuring sufficient airflow between the lower plastic structure 10 and the explosion-proof valve 40. The vent holes 131 on the central protrusion 130 not only provide airflow but also filter the bursting disc of the explosion-proof valve 40 when it explodes, preventing it from falling into the cell structure on the bottom side of the lower plastic structure 10.

[0076] Specifically, the explosion-proof valve 40 can be mounted on the lower plastic structure 10 through methods such as snapping, bonding, or screwing. In this embodiment, slots 132 are provided on both sides of the middle protrusion 130 connecting the first plate 110 and the second plate 120. The explosion-proof valve 40 snaps into these slots. This allows the explosion-proof valve 40 to be mounted on the back of the middle protrusion 130 using a simple structure, further simplifying the mounting structure between the explosion-proof valve 40 and the middle protrusion 130. Furthermore, the recessed depth of the slots 132 is less than the protruding height of the middle protrusion 130, thereby creating a gap between the lower plastic structure 10 and the explosion-proof valve 40 and ensuring sufficient exhaust space. The recessed depth of the slots 132 is equal to the thickness of the explosion-proof valve 40, allowing the top side of the lower plastic structure 10 to fit against the bottom side of the bare aluminum sheet 20, eliminating any gap between the lower plastic structure 10 and the bare aluminum sheet 20 and making the battery cell cover more compact.

[0077] More specifically, the card slot 132 can be set in the middle position of the middle protrusion 130 along the width direction Y of the lower plastic structure 10, or it can be set in a position near both sides of the middle protrusion 130 along the width direction Y of the lower plastic structure 10. Preferably, in this embodiment, the card slot 132 is set in the middle position of the middle protrusion 130 along the width direction Y of the lower plastic structure 10.

[0078] The central protrusion 130 is rectangular, and the vent holes 131 are strip-shaped and extend along the width direction Y of the lower plastic structure 10. Furthermore, multiple vent holes 131 are evenly spaced and spaced apart from each other on the central protrusion 130. For example, the number of vent holes 131 can be six, twelve, or the like, and the specific number can be set according to actual conditions and is not specifically limited in this embodiment. Furthermore, the vent holes 131 are relatively large along the width direction Y of the lower plastic structure 10, so that the central protrusion 130 can ensure sufficient exhaust area at the explosion-proof valve 40, thereby providing better air guidance. The vent holes 131 are smaller than the rupture disc of the explosion-proof valve 40 along the length direction X of the lower plastic structure 10 to prevent the rupture disc from falling into the battery cell structure on the bottom side of the lower plastic structure 10.

[0079] In the above embodiment, the electrolyte of the battery cell is injected into the interior of the battery cell from the first injection hole 121. Since a hollow stopper 140 is provided on the bottom side of the first injection hole 121, the electrolyte enters the first injection hole 121 and is injected into the interior of the battery cell in a divergent manner through the hollow area of ​​the stopper 140. Therefore, the stopper 140 can change the flow direction of the electrolyte injected into the interior of the battery cell through the first injection hole, and can divide the electrolyte into multiple beams and inject them into the interior of the battery cell in different directions, so as to greatly reduce the obstruction of the inner wall of the battery cell to the electrolyte, thereby increasing the injection speed of the first injection hole 121 and shortening its injection time. At the same time, because the electrolyte is divided into multiple beams, the electrolyte's impact on the interior of the cell is weaker during injection, and thus the electrolyte's ability to bombard the materials within the cell is weakened. This weakens the impact of the electrolyte on the electrode sheets within the cell, thereby preventing the positive or negative electrode materials on the electrode sheets from being peeled off due to the electrolyte flushing. Therefore, the disclosed embodiments can also protect the electrode sheets from damage during the injection of the electrolyte, thereby ensuring that the electrode sheets have good electrical conductivity.

[0080] The area of ​​the hollow region of the stop portion 140 is larger than the cross-sectional area of ​​the first liquid injection hole 121, so as to ensure that the electrolyte injected through the first liquid injection hole 121 can flow out of the stop portion 140 in time, thereby avoiding the stop portion 140 from blocking the electrolyte injected into the first liquid injection hole 121, and further avoiding the stop portion 140 from affecting the injection speed.

[0081] Moreover, after the liquid injection is completed, the first liquid injection hole 121 needs to be sealed by the sealing pin 30, and the inside of the battery cell is under negative pressure, and the stopper 140 can act as a stopper for the sealing pin 30 to avoid the sealing pin 30 being pressed into the inside of the battery cell due to the negative pressure and causing sealing problems, thereby avoiding leakage problems at the first liquid injection hole 121.

[0082] Therefore, the lower plastic structure 10 of the battery cell top cover can increase the injection speed and avoid leakage. In addition, the provision of the middle protrusion 130 can increase the overall strength of the lower plastic structure 10.

[0083] Figure 7 is a schematic diagram of the combined structure of a battery cell top cover provided in some embodiments of the present application, Figure 8 is a three-dimensional half-sectional view of a plain aluminum sheet provided in some embodiments of the present application, Figure 9 is a schematic diagram of the structure of an explosion-proof valve provided in some embodiments of the present application, Figure 10 is a schematic diagram of the structure of another explosion-proof valve provided in some embodiments of the present application, Figure 11 is a schematic diagram of the structure of yet another explosion-proof valve provided in some embodiments of the present application, Figure 12 is a schematic diagram of the structure of yet another explosion-proof valve provided in some embodiments of the present application, Figure 13 is a schematic diagram of the front view structure of yet another explosion-proof valve provided in some embodiments of the present application, Figure 14 is a schematic diagram of the structure of another explosion-proof valve provided in some embodiments of the present application, and Figure 15 Figure 16 is a structural schematic diagram of another explosion-proof valve provided in some embodiments of the present application, Figure 17 is a combined structural schematic diagram of another battery cell top cover provided in some embodiments of the present application, Figure 18 is a structural perspective schematic diagram of a protective sheet provided in an embodiment of the present application, Figure 19 is a structural perspective schematic diagram of a gasket provided in some embodiments of the present application, Figure 20 is a structural schematic diagram of a protective sheet body provided in some embodiments of the present application, Figure 21 is an explosion structure schematic diagram provided in some embodiments of the present application, and Figure 22 is an assembly structure diagram of a battery cell top cover and a battery cell shell provided in some embodiments of the present application.

[0084] It should be noted that the specific descriptions of the bare aluminum sheet and the lower plastic structure in the embodiments of Figures 1 to 6 are also applicable to the following embodiments. In order to avoid redundancy, the lower plastic structure will not be described in detail in the following embodiments. Please refer to the above corresponding descriptions for details.

[0085] Referring to Figures 7 and 8 , the present invention provides a battery cell top cover 300 comprising a plain aluminum sheet 301 and an explosion-proof valve 302. Plain aluminum sheet 301 has a positive electrode through-hole 303, a negative electrode through-hole 304, and an explosion-proof through-hole 305 extending through the thickness of plain aluminum sheet 301. The positive electrode through-hole 303 and the negative electrode through-hole 304 are located at two different positions relative to the explosion-proof through-hole 305. The explosion-proof valve 302 is secured to plain aluminum sheet 301 to cover the explosion-proof through-hole 305.

[0086] It should be noted that the embodiment of the present application does not limit the positional relationship between the positive electrode column through hole 303 and the negative electrode column through hole 304. When one of the positive electrode column through hole 303 and the negative electrode column through hole 304 shown in Figure 7 is a positive electrode column through hole, the other is a negative electrode column through hole.

[0087] The bare aluminum sheet 301 is the main part of the battery cell top cover, which is used to seal the battery cell to prevent the electrolyte in the battery cell from leaking out, so that a closed chemical reaction site is formed inside the battery cell to facilitate the occurrence of electrochemical reactions. The positive pole through-hole 303 is used to penetrate the positive pole, so that the positive pole can be connected to the power environment inside the battery cell and outside the battery. The negative pole through-hole 304 is used to penetrate the negative pole, so that the negative pole can be connected to the power environment inside the battery cell and outside the battery. The explosion-proof through-hole 305 is used to fix the explosion-proof valve 302, so as to facilitate the discharge of gas inside the battery cell after the explosion-proof valve 302 is opened. The positive pole through-hole 303 and the negative pole through-hole 304 are respectively located at two different positions of the explosion-proof through-hole 305 to avoid confusion between the positive and negative poles.

[0088] In some embodiments, the bare aluminum sheet 301 may also be provided with an injection hole 306 that extends through the thickness of the bare aluminum sheet 301. The injection hole 306 is used to inject electrolyte into the battery cell to allow electrochemical reactions to occur in the electrolyte, generating an electric current. Figure 8 is a three-dimensional half-section view of a bare aluminum sheet provided in one embodiment of the present application, wherein the bare aluminum sheet 301 has a positive electrode post through hole 303, a negative electrode post through hole 304, an explosion-proof through hole 305, and an injection hole 306 that extend through the thickness of the bare aluminum sheet 301.

[0089] In some embodiments, the injection hole 306 can be located away from the negative electrode through-hole 304 and the corresponding negative electrode. This can prevent the electrolyte from accidentally leaking out when the electrolyte is injected into the injection hole 306 and contacting the negative electrode, thereby causing leakage, which at least helps to improve the safety of the battery.

[0090] Referring to Figures 7 and 9 , explosion-proof valve 302 is fixed to the plain aluminum sheet 301 to cover the explosion-proof through-hole 305. The explosion-proof valve 302 has an upper surface 31 and a lower surface 32 facing each other, with the upper surface 31 of the explosion-proof valve 302 facing the explosion-proof through-hole 305. During normal use of the battery cell, the explosion-proof valve 302 can seal the battery cell and prevent leakage of the electrolyte inside the battery cell. When the air pressure inside the battery cell exceeds the explosion threshold of the explosion-proof valve 302, the explosion-proof valve 302 opens to the outside of the battery cell, allowing the gas inside the battery cell to be discharged.

[0091] In some embodiments, the explosion-proof valve 302 may be made of aluminum or an aluminum alloy. For example, the explosion-proof valve 302 may be made of 1060 aluminum. 1060 aluminum has an aluminum purity exceeding 99.6%, exhibits excellent formability, and can withstand various press working, stretching, and bending processes, facilitating the industrial production of explosion-proof valves with specific shapes. 1060 aluminum also offers excellent corrosion resistance, helping to prevent the explosion-proof valve 302 from being corroded by the battery's electrolyte, thereby preventing the explosion-proof valve 302 from weakening. For another example, the explosion-proof valve 302 may be made of a 3000 series aluminum alloy, such as 3003 aluminum alloy, 3105 aluminum alloy, or 3A21 aluminum alloy. 3000 series aluminum alloys are aluminum-manganese alloys. Due to their high manganese content, they effectively enhance the corrosion resistance of the aluminum alloy, thereby preventing the explosion-proof valve 302 from being corroded by the electrolyte and reducing its strength. The addition of manganese also improves the welding performance of the aluminum alloy, making it easier to weld and fix the explosion-proof valve 302 to the battery structure, thereby avoiding the occurrence of rupture in the weld due to pressure shock when the explosion-proof valve 302 is released, and thus helping to maintain the structural integrity of the battery.

[0092] In some embodiments, the explosion-proof valve 302 can be formed by an extrusion molding process. Extrusion molding is a type of plastic processing method, which involves applying pressure to a metal blank placed in a mold cavity, forcing the metal blank to undergo directional plastic deformation and be extruded from the die hole of the extrusion die to obtain a part or semi-finished product with the desired cross-sectional shape and size and certain mechanical properties. The process characteristics of extrusion molding determine that it can be used not only to produce rods, tubes or wire products with simple cross-sectional shapes, but also to produce structures with complex cross-sectional shapes, which is conducive to the mass production of explosion-proof valve structures with complex shapes. In addition, extruded products have high precision and good surface quality, and have good compatibility with light metals such as aluminum or light alloys such as aluminum alloys, which can reduce the defective rate of finished products and effectively improve the utilization rate of materials and the yield rate.

[0093] In some embodiments, the explosion-proof valve 302 may be in the shape of a capsule. The capsule shape refers to a combination of a quadrilateral in the middle section and two opposite sides of the quadrilateral extending into an arch shape, and the overall shape is like a capsule. The straight side of the arch coincides with the straight side of the quadrilateral. The symmetrical structure is conducive to uniform force on the explosion-proof valve 302, avoiding the stress on the explosion-proof valve 302 being concentrated in a certain area, causing the explosion-proof valve 302 to open accidentally, thereby allowing the explosion-proof valve 302 to be used normally. The bow-shaped design reduces the sharp corners of the explosion-proof valve 302, which is conducive to processing and manufacturing. For example, in extrusion molding, the material of the workpiece with rounded corners is easier to flow smoothly in the mold than that of the workpiece with sharp corners, and the stress at the corners of the workpiece will also be smaller, which can improve the quality of the explosion-proof valve 302.

[0094] Referring to Figure 9, explosion-proof valve 302 includes a bursting notch 307 and reinforcing ribs 308. Bursting notch 307 is a depression extending from upper surface 31 toward lower surface 32. It serves as a weak point in explosion-proof valve 302, designed to rupture when the pressure inside the battery cell exceeds the explosion threshold of explosion-proof valve 302. This creates an opening in explosion-proof valve 302 for gas discharge, thereby balancing the pressure inside and outside the battery cell and preventing battery explosion. Reinforcing ribs 308, located within a portion of the depression, prevent complete tearing of bursting notch 307 and control the direction of the emitted gas. The distance between the reinforcing rib 308 and the negative electrode post through hole 304 (see Figure 7) is smaller than the distance between the reinforcing rib 308 and the positive electrode post through hole 303 (see Figure 7). This can prevent the ejected gas from being ejected toward the negative electrode post through hole 304 and the negative electrode post corresponding to the negative electrode post through hole 304, thereby preventing a small amount of electrolyte brought out by the ejected gas from contacting the negative electrode post, thereby avoiding leakage of the negative electrode post, which is at least beneficial to improving the safety performance of the battery.

[0095] In some embodiments, the thickness of bursting notch 307 ranges from 0.1 mm to 0.15 mm, for example, 0.01 mm, 0.02 mm, 0.12 mm, or 0.15 mm. By controlling the thickness of bursting notch 307, the bursting threshold of bursting notch 307 can be controlled. This can be used to design bursting notch 307 to open at an appropriate pressure to avoid affecting normal battery operation. For example, this can prevent bursting notch 307 from suddenly opening during normal battery operation, thereby preventing electrolyte leakage. Another example is to prevent bursting notch 307 from remaining in place even after the battery's bursting pressure has been reached, thereby preventing explosion-proof valve 302 from losing its explosion-proof function.

[0096] In some embodiments, the cross-sectional shape of the dimple can be an inverted trapezoid with a height of 0.18 mm, a long side length of 0.3 mm, and a short side length of 0.2 mm. It is understood that when designing the blasting notch 307, different cross-sectional shapes, extended lengths, dimple depths, and dimple widths can be varied to suit different usage scenarios based on the designed blasting threshold.

[0097] In some embodiments, the thickness of the reinforcing rib 308 is greater than the thickness of the bursting notch 307. The reinforcing rib 308 is located in a portion of the recessed area and is used to strengthen the connection between the bursting notch 307 and the external platform and the connecting portion, thereby preventing the bursting notch 307 from completely tearing when the explosion-proof valve 302 is opened, thereby preventing the bursting disc from detaching and impacting other internal structures of the battery, thereby improving the safety of the battery.

[0098] In some embodiments, the thickness of the reinforcing rib 308 can be between 0.16 mm and 0.25 mm, for example, 0.16 mm, 0.18 mm, 0.21 mm, or 0.25 mm. It is understood that the thickness of the reinforcing rib 308 can be freely designed as long as the reinforcing rib 308 can strengthen the connection between the blasting score 307 and the external platform and the connecting portion.

[0099] In some embodiments, the expanded length of the reinforcing rib 308 can be less than or equal to one-sixth of the expanded length of the bursting score 307. This prevents the problem of the tearable portion of the bursting score 307 being too short, which could affect the exhaust capacity of the explosion-proof valve 302. This at least helps improve the explosion-proof effectiveness of the explosion-proof valve 302, thereby enhancing battery safety. It should be understood that the ratio of the expanded length of the reinforcing rib 308 to the expanded length of the bursting score 307 needs to be designed in conjunction with the structure of the bursting score 307.

[0100] In some embodiments, the explosion-proof valve 302 on the battery cell top cover may also include an installation mark. The installation mark may be located on the lower surface. The installation mark may also be provided adjacent to the reinforcing rib 308. The purpose of providing the installation mark is to improve the recognition of the installation direction of the explosion-proof valve 302. This can standardize the installation direction of the explosion-proof valve 302 and guide the direction of the airflow inside the battery cell after the explosion-proof valve 302 is opened, thereby preventing the airflow from damaging the internal structure of the battery and improving the safety of the battery.

[0101] In some embodiments, the shape of the installation mark can be a glyph. In other embodiments, the shape of the installation mark can be a graphic. It is understood that as long as the installation mark is recognizable, the shape of the installation mark can be any form.

[0102] Referring to FIG. 10 , in some embodiments, explosion-proof valve 302 further includes a connecting portion 309. Connecting portion 309 includes a first outer ring portion 319 and a second outer ring portion 329. First outer ring portion 319 is disposed around the periphery of bursting score 307 and is connected to bursting score 307. Second outer ring portion 329 is disposed around the periphery of first outer ring portion 319 and is connected to first outer ring portion 319. The thickness of first outer ring portion 319 is less than or equal to the thickness of second outer ring portion 329.

[0103] The function of the connection portion 309 is to facilitate the connection between the explosion-proof valve 302 and the battery cell top cover. In some embodiments, the explosion-proof valve 302 and the battery cell top cover can be fixed by welding the connection portion 309 to the battery cell top cover, thereby sealing the battery cell and preventing the electrolyte inside the battery cell from leaking.

[0104] The second outer ring portion 329 provides a contact surface to facilitate the connection between the explosion-proof valve 302 and the cell top cover. This demarcation of a specific area to facilitate connection between the explosion-proof valve 302 and the cell top cover improves the standardization of the explosion-proof valve 302, facilitating assembly efficiency and thus improving production efficiency. It also avoids quality issues caused by incomplete alignment of the explosion-proof valve 302 and the cell top cover, thereby improving battery safety.

[0105] To facilitate the processing of the bursting score 307, the thickness of the first outer ring portion 319 can be smaller than the thickness of the second outer ring portion 329, and the thickness of the first outer ring portion 319 can be greater than the thickness of the bursting score 307. For example, when the explosion-proof valve 302 is processed using an extrusion molding process, it is usually difficult to form a bursting score with precise dimensions. The extruded explosion-proof valve 302 needs to be subjected to secondary processing to etch the bursting score 307 with precise dimensions on the explosion-proof valve 302. To facilitate the etching process, the thickness of the first outer ring portion 319 can be made smaller than the thickness of the second outer ring portion 329.

[0106] In some embodiments, the thickness of the second outer ring portion 329 can range from 0.3mm to 0.7mm. For example, 0.3mm, 0.4mm, 0.5mm, or 0.7mm. In some embodiments, the thickness of the second outer ring portion 329 is the same as the thickness of the substrate forming the explosion-proof valve 302. The second outer ring portion 329 is the portion that connects the explosion-proof valve 302 to the battery cell top cover. Therefore, the second outer ring portion 329 needs to have a certain thickness to avoid the problem of the explosion-proof valve 302 and the battery cell top cover falling off due to the second outer ring portion 329 being too thin, thereby avoiding affecting the safety of the battery. At the same time, the second outer ring portion 329 cannot be too thick, so as not to occupy too much space on other structures on the battery cell top cover, and it helps to avoid material waste.

[0107] Referring again to FIG. 10 , in some embodiments, explosion-proof valve 302 may further include a bursting disc 310 connected to the inner periphery of bursting notch 307, which is circumferentially disposed around the outer periphery of bursting disc 310. During normal battery operation, bursting disc 310 is connected to bursting notch 307, creating a sealed space within the battery cell and facilitating a stable electrochemical reaction environment. When the internal pressure of the battery cell exceeds the bursting threshold of explosion-proof valve 302, bursting notch 307 tears, disconnecting bursting disc 310 from bursting notch 307. The bursting disc 310, impacted by the internal gas flow, opens toward the exterior of the battery cell, directing the airflow and preventing the small amount of electrolyte contained in the airflow from splashing, thereby preventing corrosion of the battery structure.

[0108] In some embodiments, the reinforcing rib 308 and the bursting disc 310 may be integrally formed. This enhances the connection strength between the reinforcing rib 308 and the bursting disc 310, preventing the reinforcing rib 308 and the bursting disc 310 from separating when the explosion-proof valve 302 is opened, thereby preventing the reinforcing rib 308 from becoming incapable of guiding the direction of the ejected airflow. This at least improves battery safety.

[0109] In some embodiments, the bursting disc 310 can be a planar structure with uniform thickness. The bursting disc 310 can also have X-shaped or Y-shaped bursting reinforcement ribs 308 to prevent deformation of the bursting disc due to internal pressure in the battery cell. This prevents the bursting notch 307 from being weakened by stress applied by the bursting disc 310, thereby preventing a decrease in the bursting threshold and at least improving battery safety.

[0110] In some embodiments, referring to FIG. 11 , a bursting disc 310 may include an internal platform 311 and an external platform 312 arranged around the periphery of the internal platform 311 , wherein the external platform 312 is connected to the internal platform 311 , and the thickness of the internal platform 311 is greater than the thickness of the external platform 312 . This increases the strength of the bursting disc 310 , avoids deformation of the bursting disc 310 , reduces the stress exerted on the bursting notch 307 by the bursting disc 310 , and helps avoid changes in the bursting threshold of the bursting notch 307 , thereby improving the safety of the battery.

[0111] In some embodiments, the thickness of the outer platform 312 is greater than the thickness of the bursting notch 307. This allows the opening of the explosion-proof valve 302 to be precisely controlled at the bursting notch 307, avoiding the problem of the opening of the explosion-proof valve 302 being unstable. This helps control the direction of the gas ejected after the explosion-proof valve 302 is opened, preventing the small amount of electrolyte contained in the ejected gas from corroding the battery structure, and thus improving battery safety.

[0112] In some embodiments, the thickness of the internal platform 311 may be less than or equal to the thickness of the connecting portion 309. In other embodiments, the thickness of the internal platform 311 may be greater than the thickness of the connecting portion 309. The thickness of the internal platform 311 is affected by the manufacturing process of the explosion-proof valve 302. For example, when the explosion-proof valve 302 is manufactured using an extrusion one-piece molding process, due to the good plastic deformation ability of the material, the material of certain parts of the explosion-proof valve 302 can be squeezed to the internal platform 311, resulting in the thickness of the internal platform 311 being greater than the thickness of the connecting portion 309. In this way, the thickness of the bursting disc 310 is increased, which can at least increase the strength of the bursting disc 310, which is beneficial to prevent the bursting disc 310 from being easily deformed and improve the safety of the battery.

[0113] In some embodiments, referring to FIG. 12 , the bursting disc 310 may further include a first inclined portion 313. The first inclined portion 313 is connected between the external platform 312 and the internal platform 311, and the thickness of the first inclined portion 313 gradually increases in the direction from the external platform 312 toward the internal platform 311 until it reaches the same thickness as the internal platform 311. The first inclined portion 313 forms a transition between the external platform 312 and the internal platform 311, reducing the manufacturing difficulty of the explosion-proof valve 302. Furthermore, the first inclined portion 313 reduces stress on the corner structures of the explosion-proof valve 302, thereby preventing damage caused by excessive stress concentration at the corners of the explosion-proof valve 302 and improving product quality.

[0114] In some embodiments, referring to FIG. 13 , the first inclined portion 313 includes a first inclined surface 33 and a bottom surface 34 directly opposite the first inclined surface 33 , wherein the bottom surface 34 is a portion of the lower surface 32 . The first inclined surface 33 connects the surface of the inner platform 311 and the surface of the outer platform 312 . The angle between the first inclined surface 33 and the normal to the bottom surface 34 can be in the range of 60°-89°, for example, 60°, 75°, 85°, or 89°. It will be understood that as long as the first inclined portion 313 can function to connect the thickness of the outer platform 312 with the thickness of the inner platform 311 , the angle between the first inclined surface 33 and the normal to the bottom surface 34 can be freely designed based on the type of processing technology used for the explosion-proof valve.

[0115] In some embodiments, referring to FIG14 , the explosion-proof valve 302 may further include an inner recess 314. The inner recess 314 is located in the central region of the bursting disc 310, and the inner recess 314 is recessed from the upper surface 31 toward the lower surface 32 of the explosion-proof valve 302, with the internal platform 311 surrounding the outer periphery of the inner recess 314. The process for forming the inner recess 314 may include a stamping process, in which the formed explosion-proof valve 302 is reprocessed using a press and a template. In the process of forming the explosion-proof valve 302, the explosion-proof valve 302 will inevitably have an uneven surface. The formation of the inner recess 314 can reduce the degree of unevenness on the surface of the explosion-proof valve 302, resulting in an explosion-proof valve 302 with better surface quality, thereby avoiding quality problems caused by uneven stress on the surface of the explosion-proof valve 302, which is beneficial to improving the safety of the battery.

[0116] In some embodiments, the thickness of the inner recess 314 can be greater than the thickness of the bursting notch 307. This can prevent the explosion-proof valve 302 from opening at the inner recess 314 but not at the bursting notch 307, or from opening at both the inner recess 314 and the bursting notch 307 simultaneously. This helps control the opening position of the explosion-proof valve 302, thereby controlling the direction of the airflow from the battery after the explosion-proof valve 302 is opened, and preventing the small amount of electrolyte carried by the airflow from corroding the battery structure.

[0117] In some embodiments, the thickness of the inner recess 314 can be less than or equal to the thickness of the connecting portion 309. In other embodiments, the thickness of the inner recess 314 can be greater than the thickness of the connecting portion 309. The thickness of the inner recess 314 can be freely designed based on different manufacturing processes. However, it should be understood that regardless of the manufacturing process, the thickness of the inner recess 314 is less than the thickness of the internal platform 311.

[0118] In some embodiments, referring to FIG. 15 , the bursting disc 310 may further include a second inclined portion 315. The second inclined portion 315 is connected between the internal platform 311 and the inner recess 314, and the thickness of the second inclined portion 315 gradually decreases along the direction from the internal platform 311 toward the inner recess 314. The second inclined portion 315 forms a transition between the inner recess and the internal platform 311, reducing the manufacturing difficulty of the explosion-proof valve 302. Furthermore, the second inclined portion 315 reduces stress at the corners of the explosion-proof valve 302, helping to prevent damage caused by excessive stress concentration at the corners, thereby improving product quality.

[0119] In some embodiments, referring to FIG. 16 , the second inclined portion 315 includes a second inclined surface 35 and a second bottom surface 36 that is opposite the second inclined surface 35 , wherein the second bottom surface 36 is a portion of the lower surface 32 . Furthermore, the second inclined surface 35 connects the surface of the internal platform 311 and the surface of the inner recess 314 . The angle between the second inclined surface 35 and the normal to the second bottom surface 36 can be less than or equal to 30°, for example, 30°, 28°, 15°, or 9°. It will be appreciated that, as long as the second inclined portion can connect the thickness of the internal platform 311 and the thickness of the inner recess 313 , the angle between the second inclined surface 35 and the normal to the second bottom surface 36 can be freely designed based on the different processing techniques used for the explosion-proof valve 302 .

[0120] In some embodiments, with reference to Figure 17, the battery cell top cover 300 also includes a protective sheet 316. The protective sheet 316 is fixed to the bare aluminum sheet 301 and covers the explosion-proof through-hole 305 (with reference to Figure 7). The protective sheet 316 is used to protect the explosion-proof valve 302 (with reference to Figure 7), so that the explosion-proof valve 302 is protected from damage by foreign matter, and to avoid damage to the explosion-proof valve that causes it to be unable to be used normally, thereby avoiding the explosion of the battery, which is at least conducive to improving the safety of the battery. In addition, the protective sheet 316 can also be used to block a small amount of electrolyte brought out by the ejected airflow after the explosion-proof valve 302 is opened, to avoid the electrolyte from being ejected with the airflow and splashing onto the negative pole, causing the battery cell to leak electricity.

[0121] In some embodiments, the protective sheet 316 can be made of transparent or translucent material, so that the upper surface of the explosion-proof valve 302 can be easily observed, which is conducive to timely detection of damage to the explosion-proof valve 302 so as to take measures to avoid safety problems caused by using the explosion-proof valve 302 when it is damaged, and is conducive to improving the safety of the battery.

[0122] In some embodiments, referring to Figures 18 to 20, the protective sheet 316 can be composed of a gasket 317 and a protective sheet body 318. The protective sheet body 318 is fixed on the gasket 317 and covers the explosion-proof through-hole 305 (refer to Figure 7), and the gasket 317 is fixed on the bare aluminum sheet 301 and surrounds the periphery of the explosion-proof through-hole 305. In this way, a specific area is set to fix the protective sheet 316 to the bare aluminum sheet 301, which can improve the standardization of the battery cell top cover, help improve assembly efficiency, thereby improving production efficiency, and avoid quality problems caused by incomplete alignment of the protective sheet 316 with the battery cell top cover, which is beneficial to improving the safety of the battery. Figure 19 is a structural perspective schematic diagram of a gasket provided in an embodiment of the present application, and Figure 20 is a structural schematic diagram of a protective sheet body provided in an embodiment of the present application.

[0123] In some embodiments, referring to FIG18 , the protective sheet 316 may further include an opening 320 extending through the thickness of the protective sheet 316. The opening 320 serves to form a gas flow channel, preventing the gas inside the battery cell from being blocked from escaping after the explosion-proof valve is opened, thereby preventing the battery cell from exploding due to increased internal pressure.

[0124] In some embodiments, the opening 320 is located in the edge area of ​​the protective sheet away from the liquid injection port. This can prevent the residual electrolyte from entering the cavity between the protective sheet 316 and the explosion-proof valve 302 through the opening 320 after the liquid is injected into the liquid injection port, thereby preventing the electrolyte from corroding the explosion-proof valve, thereby avoiding the problem of the explosion-proof valve 302 being unable to be used normally after being damaged.

[0125] In some embodiments, the distance from the end of the opening 320 to the center of the protective sheet 316 is smaller than the distance from the edge of the protective sheet to the center of the protective sheet 316. This can control the direction and range of the gas ejected through the opening 320, reduce the damage to the battery structure caused by the ejected gas, and at least help improve the safety of the battery.

[0126] In some embodiments, the shape of the opening 320 can be circular. In other embodiments, the shape of the opening 320 can be square. In still other embodiments, the shape of the opening 320 can also be in the shape of a letter. It will be understood that the function of the opening 320 is to enable gas flow between the cavity between the protective sheet 316 and the explosion-proof valve 302 and the external environment, so the shape of the opening 320 can be various.

[0127] In some embodiments, the opening 320 is located in the edge area of ​​the protective sheet 316 away from the negative electrode through hole and the corresponding negative electrode side, which helps to prevent the electrolyte sprayed through the opening 320 from splashing onto the negative electrode and causing leakage of the negative electrode, thereby avoiding sparks caused by leakage and improving the safety of the battery.

[0128] In some embodiments, the width of the opening 320 within the protective sheet 316 is less than 1 mm in a direction perpendicular to the opening 320 and pointing toward the center of the protective sheet 316. For example, when the opening 320 is rectangular with its short side toward the center of the protective sheet 316, the length of the short side of the opening 320 within the protective sheet 316 can be 0.1 mm, 0.2 mm, 0.5 mm, or 1 mm, etc. This prevents foreign matter from entering the cavity between the protective sheet 316 and the explosion-proof valve 302 due to the excessive width of the opening 320, thereby preventing foreign matter from damaging or corroding the explosion-proof valve, causing the explosion-proof valve 302 to malfunction, thereby improving battery safety.

[0129] 21 , in some embodiments, the cell top cover 300 may further include a positive electrode upper plastic 321 , a negative electrode upper plastic 322 , a positive electrode sealing ring 323 , a negative electrode sealing ring 324 , a lower plastic structure 325 , a positive electrode column 326 , or a negative electrode column 327 and other structures.

[0130] FIG22 is an assembly structure diagram of a battery cell top cover 300 and a battery cell shell 400 provided in an embodiment of the present application, where the battery cell top cover 300 is installed on top of the battery cell shell 400 .

[0131] The battery cell top cover 300 provided in the above-mentioned disclosed embodiment includes a plain aluminum sheet 301 and an explosion-proof valve 302. The plain aluminum sheet 301 is the main part of the battery cell top cover 300 and is used to seal the battery cell. The plain aluminum sheet 301 has a positive pole through-hole 303, a negative pole through-hole 304 and an explosion-proof through-hole 305 that penetrate the thickness of the plain aluminum sheet 301. The positive pole through-hole 303 is used to penetrate the positive pole, so that the positive pole can be connected to the power environment inside the battery cell and outside the battery. The negative pole through-hole 304 is used to penetrate the negative pole, so that the negative pole can be connected to the power environment inside the battery cell and outside the battery. The explosion-proof through-hole 305 is used to fix the explosion-proof valve 302, so as to facilitate the discharge of gas inside the battery cell after the explosion-proof valve 302 is opened. The positive pole through-hole 303 and the negative pole through-hole 304 are respectively located at two different positions of the explosion-proof through-hole 305 to avoid confusion between the positive and negative poles. The explosion-proof valve 302 is fixed on the plain aluminum sheet 301 to cover the explosion-proof through-hole 305. The explosion-proof valve 302 has a relative upper surface 31 and a lower surface 32, and the upper surface 31 of the explosion-proof valve 302 faces the explosion-proof through-hole 305. When the battery cell is in normal use, the explosion-proof valve 302 can seal the battery cell to prevent leakage of the electrolyte inside the battery cell. The explosion-proof valve 302 includes a bursting notch 307 and a reinforcing rib 308. The bursting notch 307 is a pit that is concave from the upper surface 31 toward the lower surface 32. The bursting notch 307 is a weak part on the explosion-proof valve 302, which is used to rupture when the air pressure inside the battery cell is greater than the bursting threshold of the explosion-proof valve 302, so that an opening for discharging gas is formed on the explosion-proof valve 302, thereby balancing the air pressure inside and outside the battery cell and preventing the battery from exploding. The reinforcing rib 308 is located within a portion of the recessed area to prevent complete tearing of the blasting notch 307 and thereby control the direction of the ejected gas. The distance between the reinforcing rib 308 and the negative electrode post through-hole 304 is smaller than the distance between the reinforcing rib 308 and the positive electrode post through-hole 303. This prevents the ejected gas from being ejected toward the negative electrode post through-hole 304 and the corresponding negative electrode post. This prevents a small amount of electrolyte carried by the ejected gas from coming into contact with the negative electrode post, thereby preventing leakage from the negative electrode post and, at the very least, improving battery safety.

[0132] It is worth noting that in the embodiments provided in Figures 1 to 6 and the embodiments provided in Figures 7 to 22, similar elements may use different terms, for example, the fourth pole through hole 230 and the positive pole through hole 303, the third pole through hole 230 and the negative pole through hole 304, but the positions and functions are similar, and the details of each embodiment can be implemented in conjunction with each other without conflict.

[0133] The above is a detailed introduction to the "lower plastic structure of the battery cell top cover and the battery cell top cover" provided in the embodiment of the present application. Specific examples are used herein to illustrate the principles and implementation methods of the embodiments of the present application. The description of the above implementation methods is only used to help understand the ideas of the embodiments of the present application. There may be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as a limitation on the embodiments of the present application. Those skilled in the art will understand that the above-mentioned implementation methods are specific embodiments for implementing the present application, and in actual applications, various changes can be made to them in form and detail without departing from the spirit and scope of the present application.

Claims

1. A battery cell top cover, characterized in that: include: Light aluminum sheet; A lower plastic structure, wherein the top side of the lower plastic structure is arranged on the bottom side of the smooth aluminum sheet; Wherein, the lower plastic structure includes a first plate body, a second plate body, and a middle protrusion located between the first plate body and the second plate body, and the middle protrusion is protruded relative to the bottom side of the first plate body and the bottom side of the second plate body; A first pole through hole is provided on the first plate body; a first liquid injection through hole and a second pole through hole are provided on the second plate body; and a stopper protruding from the peripheral side of the first liquid injection through hole is provided on the bottom side of the second plate body, the stopper is a hollow structure, and the area of ​​the hollow region of the stopper is larger than the cross-sectional area of ​​the first liquid injection through hole.

2. The battery cell top cover according to claim 1, characterized in that: The stopper comprises a side surface and a bottom surface, the side surface is connected to the bottom side of the second plate body and surrounds the periphery of the first liquid injection through hole, and the side surface extends in a direction away from the second plate body and is connected to the bottom surface; A plurality of diversion holes are evenly arranged on the side surface along its circumference at intervals, and the sum of the areas of all the diversion holes is greater than the cross-sectional area of ​​the first liquid injection through hole.

3. The battery cell top cover according to claim 1 or 2, characterized in that: The first plate body and the second plate body are respectively provided with side end protrusions on opposite sides thereof. The side end protrusions are protruded from the bottom side of the first plate body and the bottom side of the second plate body, and a plurality of holes are provided on the side end protrusions.

4. The battery cell top cover according to claim 3, characterized in that: The side end protrusion is in a frame structure, and a plurality of reinforcing ribs extending along the length direction of the lower plastic structure are arranged inside the side end protrusion.

5. The battery cell top cover according to any one of claims 1 to 4, characterized in that: It also includes a sealing pin, and the plain aluminum sheet is provided with a second liquid injection hole having the same central axis as the first liquid injection hole; the sealing pin is inserted into the second liquid injection hole, and the gap between the bottom end of the sealing pin and the bottom of the stopper is set at 0.5mm-2mm.

6. The battery cell top cover according to claim 5, characterized in that: The second liquid injection through hole is a stepped hole including a first hole segment and a second hole segment, the radial dimension of the first hole segment is larger than the radial dimension of the second hole segment, and the second hole segment is closer to the first liquid injection through hole.

7. The battery cell top cover according to any one of claims 1 to 4, characterized in that: It also includes an explosion-proof valve. The middle protrusion is provided with a plurality of vent holes. The explosion-proof valve is installed on the back side of the middle protrusion and is arranged opposite to the plurality of vent holes.

8. The battery cell top cover according to claim 7, characterized in that: The middle protrusion is provided with card slots at both sides connecting the first plate body and the second plate body, the explosion-proof valve is inserted into the card slots, and the recessed depth of the card slots is smaller than the protruding height of the middle protrusion.

9. The battery cell top cover according to claim 7, characterized in that: The middle protrusion is rectangular, the ventilation holes are strip-shaped and extend along the width direction of the lower plastic structure; and a plurality of ventilation holes are evenly arranged on the middle protrusion at intervals.

10. The battery cell top cover according to claim 1, characterized in that: The bare aluminum sheet has a positive pole through hole, a negative pole through hole and an explosion-proof through hole that penetrate the thickness of the bare aluminum sheet, and the positive pole through hole and the negative pole through hole are respectively located at two different positions of the explosion-proof through hole; it also includes: an explosion-proof valve, the explosion-proof valve has a relative upper surface and a lower surface, the explosion-proof valve is fixed on the bare aluminum sheet to cover the explosion-proof through hole, and the upper surface faces the explosion-proof through hole; wherein, the explosion-proof valve includes a bursting mark and a reinforcing rib, the bursting mark is a pit recessed from the upper surface toward the lower surface, the reinforcing rib is located in a partial area of ​​the pit, and the distance between the reinforcing rib and the negative pole through hole is smaller than the distance between the reinforcing rib and the positive pole through hole.

11. The battery cell top cover according to claim 10, characterized in that: The thickness of the blasting marks ranges from 0.1 mm to 0.15 mm.

12. The battery cell top cover according to claim 10, characterized in that: The thickness of the reinforcing rib is greater than the thickness of the blasting notch.

13. The battery cell top cover according to claim 12, characterized in that: The thickness of the reinforcing ribs ranges from 0.16 mm to 0.25 mm.

14. The battery cell top cover according to claim 10, characterized in that: The expanded length of the reinforcing rib is less than or equal to one sixth of the expanded length of the blasting notch.

15. The battery cell top cover according to claim 10, characterized in that: The explosion-proof valve further includes an installation mark, which is located on the lower surface and is disposed adjacent to the reinforcing rib.

16. The battery cell top cover according to claim 10, characterized in that: The explosion-proof valve further comprises a connecting portion, wherein the connecting portion comprises: A first outer ring portion, the first outer ring portion is arranged around the outer circumference of the blasting notch, and the first outer ring portion is connected to the blasting notch; A second outer ring portion, wherein the second outer ring portion is disposed around the outer circumference of the first outer ring portion and is connected to the first outer ring portion; Wherein, the thickness of the first outer ring portion is less than or equal to the thickness of the second outer ring portion.

17. The battery cell top cover according to claim 16, characterized in that: The thickness of the second outer ring portion ranges from 0.3 mm to 0.7 mm.

18. The battery cell top cover according to claim 16, characterized in that: The explosion-proof valve further comprises a bursting disc, wherein the bursting disc is connected to the inner periphery of the bursting notch, and the bursting notch is arranged around the outer periphery of the bursting disc.

19. The battery cell top cover according to claim 18, characterized in that: The reinforcing rib and the bursting disc are an integrally formed structure.

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