Top cover assembly, single battery cell and battery pack

Abstract

The invention relates to the technical field of batteries, and provides a top cover assembly, a single battery cell and a battery pack. The top cover assembly comprises a plastic part and a cover plate. A pressure relief opening is formed in the cover plate. The plastic part is connected with the side, close to the electrode assembly, of the cover plate. The plastic part has a fracture area. The fracture area is arranged close to the pressure relief opening. And the fracture area is configured to be fractured under the action of air pressure in the battery cell. Therefore, the anti-explosion valve structure can be formed on the top cover assembly without a stamping or welding mode, and the stability of the opening force of the anti-explosion valve can be ensured.

Description

Technical Field

[0001] The present invention relates to the technical field of batteries, and in particular to a top cover assembly, a single cell and a battery pack. Background Art

[0002] In the related art, the battery explosion-proof valve is usually formed on the top cover assembly by stamping or welding. For the explosion-proof valve formed by stamping on the top cover assembly, stamping will destroy the surface coating, resulting in metal exposure and poor corrosion resistance. In order to improve the corrosion resistance, nickel is usually plated on its surface, and the surface is pickled after nickel plating. Nickel plating will increase the strength of the notch of the explosion-proof valve, and pickling will cause a certain degree of corrosion in the notch. As a result, the strength of each notch is different, resulting in poor stability of the notch, making the opening force of the explosion-proof valve unstable. For the explosion-proof valve formed by welding on the top cover assembly, welding will cause defects in the top cover assembly, reducing its safety. In addition, the welding method is not suitable for all metals and its applicability is low. Summary of the invention

[0003] The embodiments of the present invention provide a top cover assembly, a single cell and a battery pack, wherein a fracture zone is formed on a plastic part, a pressure relief port is formed on a cover plate, and the explosion-proof valve structure is formed by the combination of the two, and the explosion-proof valve structure can be formed on the top cover assembly without stamping or welding. At the same time, the plastic part can be injection molded, and the thickness of the fracture zone can be well controlled, so as to control the opening force of the explosion-proof valve and ensure the stability of the opening force of the explosion-proof valve.

[0004] In a first aspect, an embodiment of the present invention provides a top cover assembly, which is applied to a battery cell, wherein the battery cell includes an electrode assembly, and the top cover assembly includes:

[0005] A cover plate is constructed with a pressure relief port;

[0006] A plastic part is connected to a side of the cover plate close to the electrode assembly, and the plastic part has a fracture zone, which is arranged close to the pressure relief port and is configured to fracture after being acted upon by the internal gas pressure of the battery cell.

[0007] In one embodiment, along the height direction of the battery core, the projection of the fracture area at least covers a portion of the pressure relief port.

[0008] In one embodiment, the plastic component is injection molded on the cover.

[0009] In one embodiment, along the direction from the edge of the fracture zone to the central axis of the fracture zone, the thickness of at least a portion of the fracture zone decreases gradually.

[0010] In one embodiment, the minimum thickness of the fracture zone is D, which satisfies: 0.1 mm ≤ D ≤ 0.8 mm.

[0011] In one embodiment, a groove is formed on a side of the plastic member away from the cover plate, and the fracture zone is located at a position of the plastic member corresponding to the groove.

[0012] In one embodiment, the plastic component is configured with a first protrusion protruding toward the cover plate, and the first protrusion is engaged with the pressure relief port.

[0013] In one embodiment, the height of the first protrusion is H1, and the height of the pressure relief port is H2, satisfying: H1≤H2.

[0014] In one embodiment, the plastic part is configured with a second protrusion protruding in a direction away from the cover plate, and the second protrusion is configured to abut against the electrode assembly, or the second protrusion is configured to be spaced apart from the electrode assembly.

[0015] In one embodiment, the second protrusion includes a first protrusion segment and a second protrusion segment spaced apart at opposite sides of the fracture zone, the first protrusion segment, the fracture zone and the second protrusion segment form an air chamber, and the air chamber is configured to accommodate gas generated by the electrode assembly.

[0016] In one embodiment, the cover plate is configured to be deformed along the pressure relief port under the action of the internal gas pressure of the battery cell after the fracture zone is fractured.

[0017] In one embodiment, the pressure relief port is configured as an arc-shaped opening, and the central angle corresponding to the arc-shaped opening is β, satisfying: 180°≤β≤360°.

[0018] In one embodiment, a terminal assembly is connected to the plastic part, and the cover plate is arranged on the periphery of the terminal assembly, wherein the pressure relief port extends along the circumference of the terminal assembly, and the terminal assembly is configured to move in a direction away from the electrode assembly after being affected by the internal air pressure of the battery cell, and to be separated from the current collector of the battery cell after the fracture zone is fractured.

[0019] In one embodiment, the plastic part is injection molded on the terminal assembly and the cover plate.

[0020] In one embodiment, the cover plate comprises:

[0021] A first plate body is arranged around the periphery of the terminal assembly, and the first plate body is connected to the plastic part;

[0022] A second plate body is arranged around the periphery of the first plate body, the second plate body is spaced apart from the first plate body and forms the pressure relief port, and the second plate body is connected to the plastic part;

[0023] The first plate is configured to separate from the first protruding portion of the plastic part along the position of the pressure relief port after being acted upon by the internal gas pressure of the battery cell, and to move in a direction away from the electrode assembly after the fracture zone is fractured.

[0024] In one embodiment, the plastic part includes:

[0025] The main body has a mounting channel, and the terminal assembly is arranged in the mounting channel;

[0026] A first connecting portion connected to the outer peripheral surface of the main body at an angle;

[0027] The second connecting portion is connected to the outer peripheral surface of the main body at an angle, and the fracture zone is located at the second connecting portion, wherein the first connecting portion and the second connecting portion are spaced apart, and the first connecting portion, the main body and the second connecting portion are surrounded to form a first slot, and at least a portion of the first plate body is snapped into the first slot.

[0028] In one embodiment, the plastic part further includes:

[0029] a bending portion connected to an end of the first connecting portion away from the main body portion, the bending portion extending in a direction away from the second connecting portion and bending in a direction of the terminal assembly, the bending portion and the first connecting portion enclosing a second slot;

[0030] Wherein, a clamping portion is configured at an edge of the terminal assembly, and the clamping portion is clamped in the second clamping groove.

[0031] In a second aspect, an embodiment of the present invention provides a single cell, comprising the top cover assembly as described above.

[0032] In a third aspect, an embodiment of the present invention provides a battery pack, comprising the aforementioned single cell.

[0033] Beneficial effects of the embodiments of the present invention:

[0034] In the embodiment of the present invention, by forming a fracture zone on the plastic part and forming a pressure relief port on the cover plate, the explosion-proof valve structure is formed by the cooperation of the two, and the explosion-proof valve structure can be formed on the top cover assembly without stamping or welding. At the same time, the plastic part can be injection molded, and the thickness of the fracture zone can be well controlled, so as to control the opening force of the explosion-proof valve and ensure the stability of the opening force of the explosion-proof valve. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0036] Figure 1 is a three-dimensional schematic diagram of a top cover assembly provided by an embodiment of the present invention;

[0037] Figure 2 is a cross-sectional view of a top cover assembly provided by an embodiment of the present invention;

[0038] Figure 3 yes Figure 2 A magnified view of part A;

[0039] Figure 4 It is one of the schematic diagrams of the pressure relief state of the top cover assembly provided by the embodiment of the present invention;

[0040] Figure 5 This is the second schematic diagram of the pressure relief state of the top cover assembly provided in an embodiment of the present invention.

[0041] Reference numerals:

[0042] 10-cover plate, 110-pressure relief port, 120-first plate body, 130-second plate body, 20-plastic part, 210-fracture zone, 220-central axis, 230-groove, 240-first protrusion, 250-second protrusion, 2510-first protruding section, 2520-second protruding section, 2530-air chamber, 260-main body, 2610-installation channel, 270-first connecting part, 280-second connecting part, 2810-first card slot, 290-bending part, 2910-second card slot, 30-terminal assembly, 310-card connecting part, 40-shell, 50-current collecting part. DETAILED DESCRIPTION

[0043] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention. In addition, it should be understood that the specific implementation methods described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention. In the present invention, unless otherwise specified, the directional words used, such as "upper" and "lower", generally refer to the upper and lower parts of the device in actual use or working state, specifically the drawing direction in the drawings; while "inside" and "outside" refer to the outline of the device.

[0044] like Figures 1 to 5 As shown, an embodiment of the present application provides a top cover assembly. The top cover assembly is applied to a battery cell. The battery cell includes an electrode assembly. Among them, the top cover assembly includes a plastic part 20 and a cover plate 10. A pressure relief port 110 is constructed on the cover plate 10. The plastic part 20 is connected to a side of the cover plate 10 close to the electrode assembly. The plastic part 20 has a fracture zone 210. The fracture zone 210 is arranged close to the pressure relief port 110. The fracture zone 210 is configured to fracture after being affected by the internal air pressure of the battery cell.

[0045] In the embodiment of the present application, by forming the fracture zone 210 on the plastic part 20 and forming the pressure relief port 110 on the cover plate 10, the explosion-proof valve structure is formed by the cooperation of the two, and the explosion-proof valve structure can be formed on the top cover assembly without stamping or welding. At the same time, the plastic part 20 can be injection molded, and the thickness of the fracture zone 210 can be well controlled, so as to control the opening force of the explosion-proof valve and ensure the stability of the opening force of the explosion-proof valve.

[0046] It is understandable that when the electrode assembly of the battery cell is punctured or otherwise damaged, the electrode assembly will produce a large amount of gas. If the gas continues to gather in the shell 40 of the battery cell, it will cause serious safety hazards. In the embodiment of the present application, by forming a fracture zone 210 on the plastic part 20, when the air pressure inside the shell 40 reaches a certain level, the air pressure inside the shell 40 can cause the fracture zone 210 to fracture. After the fracture zone 210 is broken, the gas can be discharged from the fracture of the plastic part 20 and the pressure relief port 110 of the cover plate 10.

[0047] The plastic part 20 is disposed between the cover plate 10 and the electrode assembly. The plastic part 20 is made of an insulating plastic material, and the plastic part 20 can be used to achieve the insulation setting between the cover plate 10 and the electrode assembly. At the same time, the plastic part 20 can also prevent the cover plate 10 from contacting the electrolyte and prevent the cover plate 10 from being corroded by the electrolyte. Based on the corrosion resistance of the plastic part 20 itself, the fracture zone 210 is formed on the plastic part 20, which can also prevent the electrolyte from corroding the explosion-proof valve structure and ensure the stability of the explosion-proof valve structure.

[0048] Since the plastic part 20 can be injection molded, the thickness of each position of the plastic part 20 can be easily controlled. Therefore, the injection molding thickness of the fracture zone 210 of the plastic part 20 can be controlled to control the opening value of the explosion-proof valve structure. The tensile strength of the plastic part 20 can also be controlled by controlling the injection molding thickness of other areas of the plastic part 20.

[0049] like Figure 2 As shown, in some embodiments, along the height direction of the battery cell, the projection of the fracture area 210 at least covers a portion of the pressure relief port 110 .

[0050] It is understandable that the projection of the fracture area 210 at least covers the pressure relief port 110 . When the plastic part 20 fractures at the fracture area 210 , gas can overflow from the pressure relief port 110 to prevent gas from accumulating in the battery cell housing 40 and causing safety hazards.

[0051] In some embodiments, along the height direction of the battery cell, the projection of the fracture area 210 just covers the pressure relief port 110 .

[0052] In some embodiments, along the height direction of the battery cell, the projection of the fracture zone 210 exceeds the periphery of the pressure relief port 110. For example, the pressure relief port 110 is configured as a circular ring, and the fracture zone 210 is also configured as a circular ring. The inner diameter of the fracture zone 210 is smaller than the inner diameter of the pressure relief port 110. The outer diameter of the fracture zone 210 is larger than the outer diameter of the pressure relief port 110.

[0053] In some embodiments, the plastic member 20 is injection molded on the cover 10 .

[0054] It is understandable that the cover plate 10 is a metal part. The plastic part 20 is injection molded on the cover plate 10 to ensure a reliable connection between the two and facilitate the manufacturing and molding of the top cover assembly. For example, before the plastic part 20 is injection molded, the cover plate 10 can also be placed in the injection mold, and after the plastic part 20 is injection molded, the plastic part 20 is directly connected to the cover plate 10.

[0055] like Figure 3 As shown, in some embodiments, along the direction from the edge of the fracture zone 210 to the central axis 220 of the fracture zone 210 , the thickness of at least a portion of the fracture zone 210 decreases gradually.

[0056] It is understandable that the thickness of at least part of the fracture zone 210 decreases gradually, and when it decreases to the position of the minimum thickness, this position can be fractured under the action of air pressure. In the embodiment of the present application, the thickness of at least part of the fracture zone 210 is set to decrease gradually, so that the thickness of the fracture zone 210 is smaller than the thickness of other areas of the plastic part 20, ensuring that it can be fractured at the position of the fracture zone 210 under the action of air pressure.

[0057] like Figure 3 As shown, along the direction from the edge of the fracture zone 210 to the central axis 220 of the fracture zone 210, the thickness of the fracture zone 210 first decreases and then remains unchanged. The area where the thickness remains unchanged is the minimum thickness area of ​​the fracture zone 210. Under the action of the gas pressure inside the battery cell, the minimum thickness position of the fracture zone 210 will break.

[0058] In some embodiments, the thickness of at least a portion of the fracture zone 210 may decrease linearly or exponentially.

[0059] In some embodiments, a side of the fracture zone 210 close to the cover plate 10 may be formed with a bevel, a curved surface, etc., so that the thickness of the fracture zone 210 decreases. Alternatively, a side of the fracture zone 210 close to the electrode assembly may be formed with a bevel, a curved surface, etc., so that the thickness of the fracture zone 210 decreases. Alternatively, both sides of the fracture zone 210 may be formed with a bevel, a curved surface, etc., so that the thickness of the fracture zone 210 decreases.

[0060] Please continue reading Figure 3 In some embodiments, the minimum thickness of the fracture zone 210 is D, satisfying: 0.1 mm ≤ D ≤ 0.8 mm.

[0061] It is understandable that under the action of the internal air pressure of the battery cell, the minimum thickness position of the fracture zone 210 will be broken. The fracture zone 210 can select the value of the minimum thickness of the fracture zone 210 based on the opening value of the explosion-proof valve of the top cover assembly. Among them, the minimum thickness value of the fracture zone 210 is positively correlated with the opening value of the explosion-proof valve of the top cover assembly. Specifically, the larger the opening value of the explosion-proof valve of the top cover assembly, the larger the minimum thickness value of the fracture zone 210; the smaller the opening value of the explosion-proof valve of the top cover assembly, the smaller the minimum thickness value of the fracture zone 210.

[0062] It should be noted that when the minimum thickness of the fracture zone 210 is greater than 0.8 mm, the height of the fracture zone 210 will be too large, causing the opening value of the explosion-proof valve of the top cover assembly to be too high and unable to meet the use requirements. At the same time, the minimum thickness of the fracture zone 210 is greater than 0.8 mm, which will also cause the first protrusion 240 to protrude from the pressure relief port 110 after the first protrusion 240 is set on the plastic part 20, affecting the appearance of the top cover assembly. When the minimum thickness of the fracture zone 210 is less than 0.1 mm, the fracture zone 210 cannot be molded by injection molding. Therefore, in the embodiment of the present application, the thickness of the minimum thickness area of ​​the fracture zone 210 is set within the range of 0.1 mm to 0.8 mm to ensure that the plastic part 20 can be molded by the injection molding process, and to ensure that the explosion-proof valve of the top cover assembly has a suitable opening value, and to prevent the first protrusion 240 from passing through the pressure relief port 110.

[0063] For example, the minimum thickness of the fracture zone 210 is set to 0.1 mm, 0.2 mm, 0.5 mm, 0.8 mm, or any value therebetween.

[0064] Please continue reading Figure 3 In some embodiments, a groove 230 is formed on a side of the plastic part 20 away from the cover plate 10 . The fracture area 210 is located at a position of the plastic part 20 corresponding to the groove 230 .

[0065] It is understandable that the groove 230 is formed on the side of the plastic part 20 away from the cover plate 10, and the thickness of the plastic part 20 at the position of the groove 230 will be less than the thickness of other areas of the plastic part 20. Therefore, under the action of air pressure, the position of the groove 230 is more likely to break, so that the fracture area 210 is formed at the position of the plastic part 20 corresponding to the groove 230.

[0066] In some embodiments, the cross section of the groove 230 can be set to any shape such as trapezoid, semicircle, semi-ellipse, arc, polygon, etc., ensuring that the curvature of the plastic part 20 at the position of the groove 230 is smaller than the thickness of other areas of the plastic part 20.

[0067] like Figure 2 and Figure 3 As shown, in some embodiments, the plastic part 20 is configured with a first protrusion 240 protruding toward the cover plate 10 . The first protrusion 240 is snap-fitted to the pressure relief port 110 .

[0068] It is understandable that the pressure relief opening 110 can be filled by snapping the first protrusion 240 to the plastic part 20, thereby improving the strength of the cover 10. Since the first protrusion 240 can be snapped to the pressure relief opening 110, the position of the first protrusion 240 will be compatible with the position of the fracture zone 210, and the first protrusion 240 will not affect the fracture of the fracture zone 210.

[0069] In some embodiments, the width of the first protrusion 240 is smaller than the width of the fracture zone 210 , thereby ensuring that the first protrusion 240 will not increase the width of the fracture zone 210 at the position of the minimum width, so that the fracture zone 210 can be fractured under the preset air pressure.

[0070] In some embodiments, the pressure relief port 110 is set in a circular ring shape, and the pressure relief port 110 can divide the cover plate 10 into a first plate body 120 and a second plate body 130. In this case, the first protrusion 240 is also set in a circular ring shape. The first protrusion 240 can insulate the first plate body 120 from the second plate body 130.

[0071] like Figure 3 As shown, in some embodiments, the height of the first protrusion 240 is H1, and the height of the pressure relief port 110 is H2, satisfying: H1≤H2.

[0072] It is understandable that the height of the first protrusion 240 is less than or equal to the height of the pressure relief port 110 to prevent the first protrusion 240 from passing through the pressure relief port 110 and affecting the aesthetics and pressure relief effect. If the height of the first protrusion 240 is greater than the height of the pressure relief port 110, the first protrusion 240 will be protruded from the surface of the cover plate 10, which will affect the aesthetics of the cover plate 10 on the one hand, and on the other hand, when the fracture zone 210 below is fractured, the first protrusion 240 may continue to seal the pressure relief port 110, affecting the pressure relief effect.

[0073] In some embodiments, the height of the first protrusion 240 is smaller than the height of the pressure relief port 110 , and the portion of the pressure relief port 110 that is higher than the first protrusion 240 may be configured to be gradually expanded.

[0074] Please continue reading Figure 2 In some embodiments, the plastic part 20 is configured with a second protrusion 250 protruding in a direction away from the cover plate 10. The second protrusion 250 is configured to abut against the electrode assembly, or the second protrusion 250 is configured to be spaced apart from the electrode assembly.

[0075] It is understandable that the second protrusion 250 is provided on the side of the plastic part 20 away from the cover plate 10, and the second protrusion 250 abuts against the electrode assembly, so that the electrode assembly can be supported by the second protrusion 250 to prevent the electrode assembly from arching upward due to collision. Alternatively, the second protrusion 250 can be spaced apart from the electrode assembly to reduce the degree of the electrode assembly arching upward due to collision.

[0076] In some embodiments, the first protrusion 240 and the second protrusion 250 are integrally formed on the plastic part 20. For example, the first protrusion 240, the second protrusion 250 and the plastic part 20 are integrally injection molded.

[0077] Please continue reading Figure 2 In some embodiments, the second protrusion 250 includes a first protrusion segment 2510 and a second protrusion segment 2520 spaced apart on opposite sides of the fracture zone 210. The first protrusion segment 2510, the fracture zone 210 and the second protrusion segment 2520 are arranged to form a gas chamber 2530. The gas chamber 2530 is configured to contain the gas generated by the electrode assembly.

[0078] It is understandable that a small amount of gas may be generated during normal battery charging and discharging. Alternatively, when the battery is less damaged and generates less gas, the gas can be contained in the gas chamber 2530 to provide a space for containing the gas. When the gas gradually increases and the gas pressure increases, the fracture area 210 of the plastic part 20 can be broken to achieve pressure relief.

[0079] In some embodiments, the pressure relief port 110 is set in a circular ring shape, the fracture zone 210 is also set in a circular ring shape, and the first convex section 2510 and the second convex section 2520 are both set in a circular ring shape, thereby forming a circular ring-shaped air chamber 2530.

[0080] In some embodiments, the cover plate 10 is configured to be deformed along the pressure relief opening 110 under the influence of the internal gas pressure of the battery cell after the fracture zone 210 is fractured.

[0081] It is understandable that after the fracture zone 210 is fractured, the cover plate 10 is deformed along the pressure relief port 110 due to the internal air pressure of the battery cell, and the opening size of the pressure relief port 110 can be enlarged, making it easier to release pressure quickly.

[0082] It should be noted that the deformation of the cover plate 10 along the pressure relief port 110 includes: the extension area of ​​the cover plate 10 corresponding to the pressure relief port 110 is bent in a direction away from the electrode assembly. Alternatively, the cover plate 10 is broken into two parts along the pressure relief port 110, and the part of the cover plate 10 located on the inner side of the pressure relief port 110 is separated from the part of the cover plate 10 located on the outer side of the pressure relief port 110 by the action of air pressure. As a result, at least part of the cover plate 10 is formed to fall off to expand the opening size of the pressure relief port 110. In addition, when the terminal assembly 30 is arranged in the area corresponding to the detached part of the cover plate 10, the terminal assembly 30 can also be detached from the top cover assembly to cut off the connection between the terminal assembly 30 and the current collector 50 to achieve power off.

[0083] In some embodiments, the pressure relief port 110 is configured as an arc-shaped opening. The central angle of the arc-shaped opening is β, which satisfies: 180°≤β≤360°.

[0084] It can be understood that only when the central angle corresponding to the pressure relief port 110 is greater than or equal to 180°, the cover plate 10 can be bent along the extension area of ​​the pressure relief port 110 in a direction away from the electrode assembly to ensure that the cover plate 10 can be deformed. In the embodiment of the present application, the central angle corresponding to the arc-shaped opening is preferably set to 360° to form a circular pressure relief port 110. When the cover plate 10 is subjected to the internal air pressure of the battery cell, the area of ​​the cover plate 10 located on the inner side of the arc-shaped opening can be pushed out by the air pressure and fall off to expand the opening size of the pressure relief port 110. In addition, when the terminal assembly 30 is arranged in an area corresponding to the detached part of the cover plate 10, the terminal assembly 30 can also be detached from the top cover assembly to cut off the connection between the terminal assembly 30 and the current collector 50 to achieve power off.

[0085] In some embodiments, the pressure relief opening 110 can also be set to other shapes. For example, the pressure relief opening 110 is set to an elliptical opening, a square opening, etc. It is sufficient to ensure that the pressure relief opening 110 can achieve pressure relief and the cover plate 10 can be bent or dropped along the extension area of ​​the pressure relief opening 110.

[0086] like Figure 1 As shown, in some embodiments, a terminal assembly 30 is connected to the plastic part 20. The cover plate 10 is disposed on the periphery of the terminal assembly 30. The pressure relief port 110 extends along the peripheral side of the terminal assembly 30. The terminal assembly 30 is configured to move in a direction away from the electrode assembly after being acted upon by the internal gas pressure of the battery cell, and to be separated from the current collector 50 of the battery cell after the fracture zone 210 is fractured.

[0087] It can be understood that the terminal assembly 30 is used to connect the current collector 50 to realize external power supply. Based on the cover plate 10 being arranged on the periphery of the terminal assembly 30, and the pressure relief port 110 extending along the peripheral side of the terminal assembly 30. Under the action of the internal air pressure of the battery cell, the cover plate 10 is deformed along the pressure relief port 110 by the internal air pressure of the battery cell. When the cover plate 10 is bent in the direction away from the electrode assembly, the terminal assembly 30 can be driven to move in the direction away from the electrode assembly, so that the terminal assembly 30 can be separated from the current collector 50 after the fracture zone 210 is broken. When the cover plate 10 falls off in the direction away from the electrode assembly, the terminal assembly 30 can be driven to move in the direction away from the electrode assembly, so that the terminal assembly 30 can be separated from the current collector 50 after the fracture zone 210 is broken.

[0088] In some embodiments, the plastic member 20 is injection molded on the terminal assembly 30 and the cover plate 10 .

[0089] It is understandable that the terminal assembly 30 and the cover plate 10 are both metal parts. The plastic part 20 is injection molded on the terminal assembly 30 and the cover plate 10 to ensure reliable connection between the three and facilitate the manufacturing and molding of the top cover assembly. For example, before the plastic part 20 is injection molded, the terminal assembly 30 and the cover plate 10 can be placed in an injection mold. After the plastic part 20 is injection molded, the plastic part 20 is directly connected to the terminal assembly 30 and the cover plate 10.

[0090] like Figure 2 As shown, in some embodiments, the cover plate 10 includes a first plate body 120 and a second plate body 130. The first plate body 120 is arranged around the periphery of the terminal assembly 30. The first plate body 120 is connected to the plastic part 20. The second plate body 130 is arranged around the periphery of the first plate body 120. The second plate body 130 is spaced apart from the first plate body 120 and forms a pressure relief port 110. The second plate body 130 is connected to the plastic part 20. Among them, the first plate body 120 is configured to be separated from the first protrusion 240 of the plastic part 20 along the position of the pressure relief port 110 after being acted upon by the internal air pressure of the battery cell, and moves in a direction away from the electrode assembly after the fracture zone 210 is fractured.

[0091] like Figure 1 and Figure 2As shown, the first plate body 120 and the second plate body 130 are both arranged in a circular ring shape. The outer diameter of the first plate body 120 is smaller than the inner diameter of the second plate body 130, so that the first plate body 120 and the second plate body 130 are arranged at intervals to form a circular ring-shaped pressure relief port 110. When the cover plate 10 is subjected to the internal air pressure of the battery cell, the first plate body 120 can be separated from the first protrusion 240 of the plastic part 20 along the extension direction of the pressure relief port 110, so as to achieve the initial peeling of the cover plate 10 and the plastic part 20. After the continuous action of the air pressure causes the fracture zone 210 to fracture, the first plate body 120 will move in a direction away from the electrode assembly so that the first plate body 120 is detached from the top cover assembly. Based on the fact that the first plate body 120 is arranged around the periphery of the terminal assembly 30, the first plate body 120 can drive the terminal assembly 30 to fall off when it falls off from the top cover assembly, so that the connection between the terminal assembly 30 and the current collector 50 is separated to achieve power off.

[0092] Please continue reading Figure 2 In some embodiments, the plastic part 20 includes a main body 260, a first connecting part 270 and a second connecting part 280. The main body 260 has a mounting channel 2610, and the terminal assembly 30 is disposed in the mounting channel 2610. The first connecting part 270 is connected to the outer peripheral surface of the main body 260 at an angle. The second connecting part 280 is connected to the outer peripheral surface of the main body 260 at an angle. The fracture zone 210 is located at the second connecting part 280. The first connecting part 270 and the second connecting part 280 are arranged at intervals, and the first connecting part 270, the main body 260 and the second connecting part 280 are surrounded to form a first card slot 2810. At least a portion of the first plate 120 is engaged with the first card slot 2810.

[0093] It is understandable that the main body 260 forms a mounting channel 2610 to connect the terminal assembly 30. The first connecting portion 270, the second connecting portion 280, and the first card slot 2810 formed by the outer surface of the main body 260 can be used to connect the first plate 120. After the plastic part 20 and the first plate 120 are connected by injection molding, it can be ensured that the first plate 120 is stably and reliably clamped in the first card slot 2810 without falling off.

[0094] In some embodiments, the first connection portion 270 and the second connection portion 280 are arranged in parallel, and the first connection portion 270 and the second connection portion 280 are both perpendicular to the outer circumferential surface of the main body 260 .

[0095] It should be noted that the breaking zone 210 is disposed at the second connecting portion 280 .

[0096] Please continue reading Figure 2In some embodiments, the plastic part 20 further includes a bending portion 290. The bending portion 290 is connected to an end of the first connecting portion 270 away from the main body 260. The bending portion 290 extends in a direction away from the second connecting portion 280 and bends in a direction toward the terminal assembly 30. The bending portion 290 and the first connecting portion 270 enclose a second slot 2910. The edge of the terminal assembly 30 is configured with a snap-fit ​​portion 310, which is snap-fitted to the second slot 2910.

[0097] It is understandable that the second slot 2910 is formed based on the bending portion 290 and the first connecting portion 270 to clamp the clamping portion 310 at the edge of the terminal assembly 30, thereby realizing a reliable connection between the terminal assembly 30 and the plastic part 20. After the top cover assembly is injection molded, the first plate 120, the main body 260, the terminal assembly 30, the first connecting portion 270 and the second connecting portion 280 located inside the fracture zone 210 will form an integral structure. The integral structure can fall off as a whole after being subjected to the internal air pressure.

[0098] In some embodiments, the main body 260 , the first connection portion 270 , the second connection portion 280 , and the bending portion 290 are integrally injection molded.

[0099] like Figure 4 and Figure 5 As shown, the top cover structure in the embodiment of the present application has at least the following two pressure relief methods.

[0100] Method 1: When the top cover assembly is affected by the gas inside the battery cell, the gas will first act on the position of the terminal assembly 30, causing the terminal assembly 30 to move away from the electrode assembly. At this time, the first plate body 120 and the plastic part 20 are peeled off first. When the air pressure reaches the opening value of the explosion-proof valve, the fracture zone 210 of the plastic part 20 breaks, and the pressure is released from the pressure relief port 110. When the fracture zone 210 is completely broken, the terminal assembly 30, the first plate body 120, and the part of the plastic part 20 located inside the fracture zone 210 will be completely flushed out, so that the terminal assembly 30 is completely separated from the current collector 50, and the power is cut off. In this way, the safety of the battery cell is ensured.

[0101] Method 2: When the top cover assembly is affected by the gas inside the battery cell, the gas will first act on the position of the terminal assembly 30, causing the terminal assembly 30 to move away from the electrode assembly. At this time, the first plate body 120 and the second plate body 130 are both peeled off from the plastic part 20. A portion of the gas can be decompressed at the connection between the second plate body 130 and the shell 40. When the air pressure reaches the opening value of the explosion-proof valve, the fracture zone 210 of the plastic part 20 breaks, and the pressure is released from the pressure relief port 110. When the fracture zone 210 is completely broken, the terminal assembly 30, the first plate body 120, and the part of the plastic part 20 located inside the fracture zone 210 will be completely flushed out, so that the terminal assembly 30 is completely separated from the current collector 50, and the power is cut off. In this way, the safety of the battery cell is ensured.

[0102] The top cover assembly in the embodiment of the present application preferably uses method 1 to achieve pressure relief.

[0103] The embodiment of the present application also provides a single cell battery. The single cell battery comprises a top cover assembly as described in the above embodiment.

[0104] In the embodiment of the present application, by forming a fracture zone 210 on the plastic part 20 and forming a pressure relief port 110 on the cover plate 10, the explosion-proof valve structure is formed by the cooperation of the two, and the explosion-proof valve structure can be formed on the top cover assembly without stamping or welding. At the same time, the plastic part 20 can be injection molded, and the thickness of the fracture zone 210 can be well controlled, so as to control the opening force of the explosion-proof valve, ensure the stability of the opening force of the explosion-proof valve, and improve the safety of the single battery cell.

[0105] The present application also provides a battery pack, which includes a single cell as described in the above embodiment.

[0106] In the embodiment of the present application, by forming a fracture zone 210 on the plastic part 20 and forming a pressure relief port 110 on the cover plate 10, the explosion-proof valve structure is formed by the cooperation of the two, and the explosion-proof valve structure can be formed on the top cover assembly without stamping or welding. At the same time, the plastic part 20 can be injection molded, and the thickness of the fracture zone 210 can be well controlled, so as to control the opening force of the explosion-proof valve, ensure the stability of the opening force of the explosion-proof valve, and improve the safety of the battery pack.

[0107] The embodiments of the present invention are described in detail above. Specific examples are used herein to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will 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 present invention.

Claims

1. A top cover assembly, applied to a battery cell, wherein the battery cell includes an electrode assembly, characterized in that: The top cover assembly comprises: A cover plate is constructed with a pressure relief port; A plastic part is connected to a side of the cover plate close to the electrode assembly, and the plastic part has a fracture zone, which is arranged close to the pressure relief port and is configured to fracture after being acted upon by the internal gas pressure of the battery cell.

2. The top cover assembly according to claim 1, characterized in that: Along the height direction of the battery core, the projection of the fracture area at least covers a portion of the pressure relief port.

3. The top cover assembly according to claim 1, characterized in that: The plastic part is injection molded on the cover plate.

4. The top cover assembly according to claim 1, characterized in that: Along the direction from the edge of the fracture zone to the central axis of the fracture zone, the thickness of at least a part of the fracture zone decreases gradually.

5. The top cover assembly according to claim 4, characterized in that: The minimum thickness of the fracture zone is D, which satisfies: 0.1 mm ≤ D ≤ 0.8 mm.

6. The top cover assembly according to claim 1, characterized in that: A groove is formed on one side of the plastic part away from the cover plate, and the fracture zone is located at a position of the plastic part corresponding to the groove.

7. The top cover assembly according to claim 1, characterized in that: The plastic part is configured with a first protruding portion protruding toward the cover plate, and the first protruding portion is clamped in the pressure relief port.

8. The top cover assembly according to claim 7, characterized in that: The height of the first protrusion is H1, and the height of the pressure relief port is H2, satisfying: H1≤H2.

9. The top cover assembly according to claim 1, characterized in that: The plastic part is configured with a second protrusion protruding in a direction away from the cover plate, and the second protrusion is configured to abut against the electrode assembly, or to be spaced apart from the electrode assembly.

10. The top cover assembly according to claim 9, characterized in that: The second protrusion includes a first protrusion segment and a second protrusion segment spaced apart at opposite sides of the fracture zone. The first protrusion segment, the fracture zone and the second protrusion segment form an air chamber, which is configured to accommodate gas generated by the electrode assembly.

11. The top cover assembly according to any one of claims 1 to 10, characterized in that: The cover plate is configured to be deformed along the pressure relief port under the action of the internal gas pressure of the battery cell after the fracture zone is fractured.

12. The top cover assembly according to claim 11, characterized in that: The pressure relief port is configured as an arc-shaped opening, and the central angle corresponding to the arc-shaped opening is β, which satisfies: 180°≤β≤360°.

13. The top cover assembly according to any one of claims 1 to 10, characterized in that: A terminal assembly is connected to the plastic part, and the cover plate is arranged on the periphery of the terminal assembly, wherein the pressure relief port extends along the circumference of the terminal assembly, and the terminal assembly is configured to move in a direction away from the electrode assembly after being affected by the internal air pressure of the battery cell, and to be separated from the current collector of the battery cell after the fracture zone is fractured.

14. The top cover assembly according to claim 13, characterized in that: The plastic part is injection molded on the terminal assembly and the cover plate.

15. The top cover assembly according to claim 13, characterized in that: The cover plate comprises: A first plate body is arranged around the periphery of the terminal assembly, and the first plate body is connected to the plastic part; A second plate body is arranged around the periphery of the first plate body, the second plate body is spaced apart from the first plate body and forms the pressure relief port, and the second plate body is connected to the plastic part; The first plate is configured to be separated from the first protruding portion of the plastic part along the pressure relief port after being acted upon by the internal gas pressure of the battery cell, and to move in a direction away from the electrode assembly after the fracture zone is fractured.

16. The top cover assembly according to claim 15, characterized in that The plastic parts include: The main body has a mounting channel, and the terminal assembly is arranged in the mounting channel; A first connecting portion connected to the outer peripheral surface of the main body at an angle; The second connecting portion is connected to the outer peripheral surface of the main body at an angle, and the fracture zone is located at the second connecting portion, wherein the first connecting portion and the second connecting portion are spaced apart, and the first connecting portion, the main body and the second connecting portion are surrounded to form a first slot, and at least a portion of the first plate body is snapped into the first slot.

17. The top cover assembly according to claim 16, characterized in that The plastic part also includes: a bending portion connected to an end of the first connecting portion away from the main body portion, the bending portion extending in a direction away from the second connecting portion and bending in a direction of the terminal assembly, the bending portion and the first connecting portion enclosing a second slot; Wherein, a clamping portion is configured at an edge of the terminal assembly, and the clamping portion is clamped in the second clamping groove.

18. A single cell, characterized in that: Comprising a top cover assembly as claimed in any one of claims 1 to 17.

19. A battery pack, characterized in that: Comprising the single battery cell as claimed in claim 18.

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