Explosion-proof valve, top cover assembly, battery cell, and battery pack

Abstract

The present disclosure relates to the technical field of batteries, and provides an explosion-proof valve, a top cover assembly, a battery cell, and a battery pack. The battery cell explosion-proof valve comprises an explosion-proof valve body and a mounting portion. The mounting portion is disposed on an outer periphery of the explosion-proof valve body and is connected to the explosion-proof valve body. The explosion-proof valve body is provided with a weak portion, the weak portion being capable of rupturing upon the internal pressure of the battery cell reaching a threshold value; and an at least partial area of the weak portion is recessed or bulged in the thickness direction of the explosion-proof valve body to form a buffer. According to the present disclosure, providing a buffer in a thinned area of the explosion-proof valve stabilizes the rupture pressure value of the explosion-proof valve.

Description

An explosion-proof valve, a top cover assembly, a battery monomer and a battery pack

[0001] Cross-reference to related disclosures

[0002] The present disclosure claims priority to the Chinese patent application No. 2024211347185, filed on May 21, 2024, entitled "A battery monomer and a battery pack", the entire content of which is incorporated herein by reference. TECHNICAL FIELD

[0003] The present disclosure relates to the technical field of batteries, and in particular to an explosion-proof valve, a top cover assembly, a battery monomer and a battery pack. BACKGROUND

[0004] The top cover is a key component of the power battery, and has a significant impact on the energy density, economy and safety of the power battery. The top cover is provided with an explosion-proof valve, which is used to open and release the internal pressure in time when the battery monomer abnormally produces gas and the internal pressure increases rapidly, so as to prevent the explosion of the battery monomer.

[0005] In the related art, the structure of the explosion-proof valve is not reasonable, which causes the burst value of the explosion-proof valve to be unstable, affecting the normal function of the explosion-proof valve. The information disclosed in this background section is intended only to enhance the understanding of the overall background of the present disclosure, and should not be construed as recognizing or implying in any form that this information constitutes prior art known to those skilled in the art. SUMMARY

[0006] The purpose of the present disclosure includes, for example, providing an explosion-proof valve, a top cover assembly, a battery monomer and a battery pack, which can buffer the stress generated during the welding installation of the explosion-proof valve, thereby improving the problem of unstable burst value of the explosion-proof valve.

[0007] Embodiments of the present disclosure can be implemented as follows:

[0008] The embodiment of the present disclosure provides an explosion-proof valve of a battery monomer, which is applied to the battery monomer and includes an explosion-proof valve body and a mounting portion.

[0009] The mounting portion is arranged at the outer periphery of the explosion-proof valve body and is connected with the explosion-proof valve body.

[0010] The weak portion can be broken when the internal pressure of the battery monomer reaches a threshold value.

[0011] At least part of the weak portion is formed with a buffer in the form of a recess or an arch along the thickness direction of the explosion-proof valve body.

[0012] Optionally, the thickness of the weak portion is less than the thickness of the explosion-proof valve body.

[0013] and / or,

[0014] The weakened portion has a center line area in the middle of the width direction of the weakened portion, and the buffer body is arranged in the center line area.

[0015] Optionally, the weakened portion has opposite first and second wall surfaces in the thickness direction of the explosion-proof valve body, the first wall surface is the outer surface of the explosion-proof valve body, and the second wall surface is the inner surface of the explosion-proof valve body.

[0016] The buffer body is recessed from the first wall surface to the second wall surface, or the buffer body is arched from the second wall surface to the first wall surface.

[0017] Optionally, the buffer body is arranged in a local area of the weakened portion.

[0018] Optionally, the buffer body has an inner wall surface and an outer wall surface, and both the inner wall surface and the outer wall surface are arc surfaces.

[0019] Optionally, both the inner wall surface and the outer wall surface are circular arc surfaces.

[0020] Optionally, the buffer body has opposite inner and outer wall surfaces, and both the inner and outer wall surfaces are spherical surfaces.

[0021] Optionally, both the inner and outer wall surfaces are spherical surfaces.

[0022] Optionally, one weakened portion is provided with a plurality of buffer bodies, and the plurality of buffer bodies are arranged at intervals.

[0023] Optionally, the plurality of buffer bodies are arranged at equal intervals.

[0024] Optionally, the plurality of buffer bodies are arranged at intervals in the width direction or the length direction of the weakened portion.

[0025] Optionally, the plurality of buffer bodies are arranged at equal intervals in the width direction or the length direction of the weakened portion.

[0026] Optionally, the thickness of the buffer body is the same as the thickness of the weakened portion.

[0027] Optionally, the buffer body is in the shape of a strip or a hemisphere.

[0028] Optionally, in the thickness direction of the top cover sheet, the thickness of the mounting portion is greater than the thickness of the explosion-proof valve body.

[0029] Optionally, the weakened portion includes a first straight line segment and a second straight line segment.

[0030] The first straight line segment and the second straight line segment intersect to form an intersection point, and the intersection point is located at a central position of the explosion-proof valve body.

[0031] Optionally, the weak part comprises a first curved segment and a second curved segment.

[0032] The first curved segment and the second curved segment are arranged in axial symmetry with respect to a center line in the width direction of the explosion-proof valve body, and / or the first curved segment and the second curved segment are arranged in axial symmetry with respect to a center line in the length direction of the explosion-proof valve body.

[0033] Embodiments of the present disclosure also provide a top cover assembly, comprising a top cover sheet and the explosion-proof valve described above.

[0034] The top cover sheet is provided with a mounting hole, and the mounting hole penetrates through the top cover sheet.

[0035] The explosion-proof valve is mounted in the mounting hole, and the mounting part is connected with the top cover sheet.

[0036] Embodiments of the present disclosure also provide a battery monomer, characterized in comprising a shell and the top cover assembly described above.

[0037] The shell has an open accommodating cavity.

[0038] The top cover sheet is arranged on one side of the opening of the shell.

[0039] Embodiments of the present disclosure also provide a battery pack, comprising the battery monomer described above.

[0040] In combination with the above technical solutions, the beneficial effects brought by embodiments of the present disclosure include, for example:

[0041] The explosion-proof valve of the battery monomer provided by the present disclosure can release the residual stress and strain generated in the welding process of the mounting part by arranging a buffer body in the weak part of the explosion-proof valve body, thereby enhancing the anti-deformation ability of the weak part, avoiding the deformation of the explosion-proof valve body due to stress pulling during the mounting process, and stabilizing the explosion value of the explosion-proof valve, thereby significantly improving the safety and reliability of the battery.

[0042] Other features and advantages of the present disclosure will be described in the following description, and some will become apparent from the description, or will be understood through implementation of the present disclosure. The purposes and other advantages of the present disclosure are achieved and obtained by the structures specifically pointed out in the description, claims, and drawings. BRIEF DESCRIPTION OF DRAWINGS

[0043] In order to more clearly illustrate the technical solutions of the embodiments of the present disclosure, the following will briefly introduce the drawings needed to be used in the embodiments. It should be understood that the following drawings only show some of the embodiments of the present disclosure, and therefore should not be considered as a limitation to the scope. For those skilled in the art, other related drawings can also be obtained from these drawings without creative labor.

[0044] Fig. 1 shows a structural schematic diagram of a battery cell provided by some embodiments of the present disclosure;

[0045] Fig. 2 shows a structural schematic diagram of a top cover assembly provided by some embodiments of the present disclosure;

[0046] Fig. 3 shows a structural schematic diagram of a first embodiment of an explosion-proof valve provided by some embodiments of the present disclosure from one perspective;

[0047] Fig. 4 shows a structural schematic diagram of the first embodiment of the explosion-proof valve provided by some embodiments of the present disclosure from another perspective;

[0048] Fig. 5 shows a sectional view of A-A part in Fig. 4;

[0049] Fig. 6 shows a sectional view of B-B part in Fig. 4;

[0050] Fig. 7 shows an enlarged view of B' part in Fig. 6;

[0051] Fig. 8 shows a structural schematic diagram of a second embodiment of an explosion-proof valve provided by some embodiments of the present disclosure from one perspective;

[0052] Fig. 9 shows a structural schematic diagram of the second embodiment of the explosion-proof valve provided by some embodiments of the present disclosure from another perspective;

[0053] Fig. 10 shows a sectional view of C-C part in Fig. 9;

[0054] Fig. 11 shows a sectional view of D-D part in Fig. 9;

[0055] Fig. 12 shows a structural schematic diagram of a third embodiment of an explosion-proof valve provided by some embodiments of the present disclosure from one perspective;

[0056] Fig. 13 shows a structural schematic diagram of the third embodiment of the explosion-proof valve provided by some embodiments of the present disclosure from another perspective;

[0057] Fig. 14 shows a sectional view of E-E part in Fig. 13;

[0058] Fig. 15 shows a sectional view of F-F part in Fig. 13;

[0059] Fig. 16 shows a structural schematic diagram of a fourth embodiment of an explosion-proof valve provided by some embodiments of the present disclosure from one perspective;

[0060] Fig. 17 shows a structural schematic view of another view of a fourth embodiment of the explosion-proof valve according to some embodiments of the present disclosure;

[0061] Fig. 18 shows a sectional view of G-G part in Fig. 17;

[0062] Fig. 19 shows a sectional view of H-H part in Fig. 17;

[0063] Fig. 20 shows a structural schematic view of a first view of a fifth embodiment of the explosion-proof valve according to some embodiments of the present disclosure;

[0064] Fig. 21 shows a structural schematic view of another view of the fifth embodiment of the explosion-proof valve according to some embodiments of the present disclosure;

[0065] Fig. 22 shows a sectional view of I-I part in Fig. 20;

[0066] Fig. 23 shows a sectional view of J-J part in Fig. 20;

[0067] Fig. 24 shows an enlarged view of J' part in Fig. 23;

[0068] Fig. 25 shows a structural schematic view of a first view of a sixth embodiment of the explosion-proof valve according to some embodiments of the present disclosure;

[0069] Fig. 26 shows a structural schematic view of another view of the sixth embodiment of the explosion-proof valve in a battery cell according to some embodiments of the present disclosure;

[0070] Fig. 27 shows a sectional view of K-K part in Fig. 26;

[0071] Fig. 28 shows a sectional view of L-L part in Fig. 26.

[0072] Main element symbol explanation: 100 - explosion-proof valve; 110 - mounting part; 120 - explosion-proof valve body; 200 - weak part; 210 - first straight line segment; 220 - second straight line segment; 230 - curved line segment; 300 - buffer body; 310 - first wall surface; 320 - second wall surface; 400 - top cover sheet; 410 - mounting hole; 500 - shell. DETAILED DESCRIPTION

[0073] The embodiments of the present disclosure are described in detail below with reference to the accompanying drawings. The embodiments described below are examples for explaining the present disclosure and should not be understood as limiting the present disclosure.

[0074] It should be noted that when an element is referred to as being "on" another element, it can be directly on the other element or intervening elements can also be present. In contrast, when an element is referred to as being "directly on" another element, there are no intervening elements present. It will be understood that when an element is referred to as being "connected" to or "coupled" to another element, it can be directly connected or coupled to the other element or intervening elements can be present. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0075] In the present disclosure, unless specifically defined otherwise, the terms "mounting", "connected", "connecting", "fixed", and the like, should be interpreted broadly, for example, can be fixed connection, can also be detachable connection, or integral; can be mechanical connection, can also be electrical connection; can be directly connected, can also be indirectly connected through intermediate media, can be internal communication of two elements or interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the present disclosure can be understood according to the specific circumstances.

[0076] In addition, the terms "first", "second", "third", etc. are used only for descriptive purposes and should not be construed as indicating or implying relative importance or an indicated number of technical features. Therefore, the features defined as "first", "second", etc. can include one or more of the features explicitly or implicitly. In the description of the present disclosure, the meaning of "a plurality of" is two or more, unless otherwise specifically defined.

[0077] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. The terminology used in the description of the template herein is only for the purpose of describing specific embodiments and is not intended to limit the present disclosure. The term "and / or" used herein includes any and all combinations of one or more of the associated listed items.

[0078] As shown in FIGS. 1-3, the present disclosure provides a battery cell which can be applied to electric devices such as vehicles, power tools, household appliances, etc. to release electric energy as a power source, and can also be applied to energy storage devices such as uninterruptible power supplies, energy storage cabinets, etc. to store electric energy.

[0079] The battery cell includes a shell 500, a top cover assembly, and a bare cell (not shown).

[0080] The shell 500 has an open accommodating cavity. That is, the interior of the shell 500 has an accommodating cavity, and the side wall of the shell 500 is provided with an opening communicating with the accommodating cavity, which is located at one side of the length direction or width direction of the shell 500.

[0081] The top cover assembly comprises a top cover sheet 400 and an expansion valve 100. The expansion valve 100 is mounted to the top cover sheet 400. The top cover sheet 400 is connected to the shell 500 and covers the opening to seal the opening by the top cover sheet 400, thereby forming a sealed containing cavity. The bare electric core is mounted in the containing cavity and electrically connected to the pole of the top cover assembly.

[0082] The top cover sheet 400 and the shell 500 can be connected by welding to improve the connection stability between the top cover sheet 400 and the shell 500 and improve the sealing quality of the top cover sheet 400 to the opening, thereby avoiding the liquid or other impurities outside the shell 500 from entering the containing cavity through the opening.

[0083] Further, the top cover sheet 400 has a mounting hole 410 penetrating the top cover sheet 400 along the thickness direction of the top cover sheet 400, and the mounting hole 410 is in communication with the containing cavity. The explosion-proof valve 100 is mounted in the mounting hole 410. When the bare electric core in the containing cavity has a problem such as thermal runaway, which causes the internal pressure of the containing cavity to be too high, the explosion-proof valve 100 can be broken to allow the internal gas to be discharged through the broken opening of the explosion-proof valve, thereby releasing the pressure in the containing cavity to avoid explosion of the single battery.

[0084] Specifically, the explosion-proof valve 100 comprises an explosion-proof valve body 120 and a mounting portion 110. The mounting portion 110 is arranged at the outer periphery of the explosion-proof valve body 120 and connected to the explosion-proof valve body 120. For example, the mounting portion 110 can be connected to the side wall of the explosion-proof valve body 120 by surrounding. The mounting portion 110 is connected to the hole wall of the mounting hole 410. For example, the mounting portion 110 and the hole wall of the mounting hole 410 are connected by welding or integrally connected and formed to realize the sealing connection between the mounting portion 110 and the hole wall of the mounting hole 410. The explosion-proof valve 100 seals the mounting hole 410 to prevent the liquid or other impurities outside from entering the containing cavity through the mounting hole 410.

[0085] It should be noted that the axis of the explosion-proof valve 100 coincides with or is parallel to the axis of the mounting hole 410, thereby avoiding the explosion-proof valve 100 from being inclined in the mounting hole 410 to ensure the uniformity of the force received by each position of the explosion-proof valve body 120, thereby ensuring the stability of the explosion-proof valve 100.

[0086] Further, the explosion-proof valve body 120 is provided with a weak portion 200. The shape of the weak portion 200 can be at least one of a straight line type, a curved line type, a broken line type, a letter type, a number type, a circular type, an elliptical type and a polygonal type, or a combination of two or more thereof.

[0087] The weak portion 200 is configured to break to release pressure when the internal pressure of the battery cell reaches a threshold value. Specifically, when the internal pressure of the battery cell reaches the threshold value, the weak portion 200 can break under the action of the pressure, so that the explosion-proof valve 100 can be opened under the action of the pressure. That is, when the explosion-proof valve 100 is opened, the explosion-proof valve 100 has no sealing effect on the mounting hole 410, and the accommodation cavity is in communication with the outside of the shell 500 through the mounting hole 410, so that the gas generated in the battery cell can be discharged through the mounting hole 410, and the pressure is released, thereby avoiding the explosion of the battery cell due to the excessive internal pressure of the battery cell, and improving the safety of the battery cell during use.

[0088] It should be noted that the reason why the weak portion 200 can break after the internal pressure of the battery cell reaches the threshold value is that the pressure resistance of the weak portion 200 is less than that of other parts of the explosion-proof valve 100, so that the weak portion 200 breaks when the internal pressure exceeds the threshold value, thereby achieving the function of pressure relief. For example, the thickness of the weak portion 200 is set to be less than the thickness of the explosion-proof valve body 120. When the internal pressure of the battery cell reaches the threshold value, the weak portion 200 can be disconnected under the action of the pressure value, and a gap is formed on the explosion-proof valve body 120, so that the pressure in the battery cell can be released through the gap, thereby preventing the battery cell from exploding due to excessive pressure.

[0089] Further, at least part of the weak portion 200 is formed with a buffer 300 in the thickness direction of the explosion-proof valve body 120 in a concave or arched manner.

[0090] The buffer 300 can release the residual stress and strain generated during the welding process between the mounting portion 110 of the explosion-proof valve 100 and the hole wall of the mounting hole 410, so as to enhance the anti-deformation ability of the weak portion 200 in the explosion-proof valve 100, avoid the weak portion 200 of the explosion-proof valve 100 being stressed and even deformed during the welding process between the explosion-proof valve 100 and the hole wall of the mounting hole 410, and ensure the integrity of the weak portion 200 and the stability of the explosion-proof value of the explosion-proof valve 100.

[0091] In the present embodiment, the weak portion 200 has at least two end portions, and when the weak portion 200 breaks under the action of the pressure, a part of the explosion-proof valve body 120 is turned over along the weak portion 200 and forms an exhaust port on the explosion-proof valve body 120, so as to effectively avoid the part of the explosion-proof valve body 120 from being separated from the explosion-proof valve body 120 under the action of the pressure.

[0092] As shown in FIGS. 3 and 25, in some embodiments of the present disclosure, a plurality of buffers 300 are arranged on the weak portion 200, and the plurality of buffers 300 are arranged continuously or at intervals.

[0093] It should be noted that the side wall of the weakened portion 200 and the buffer body 300 have a gap in the direction perpendicular to the thickness direction of the explosion-proof valve 100. The weakened portion 200 refers to the side of the thickness direction of the explosion-proof valve body 120, and the surface of the explosion-proof valve body 120 is processed to form the weakened portion 200, that is, the thickness of the weakened portion 200 is less than the thickness of the explosion-proof valve body 120.

[0094] It can be understood that the weakened portion 200 has a bottom wall and a side wall connected to the edge of the bottom wall. The buffer body 300 specifically refers to a part of the bottom wall of the weakened portion 200 being concave or arched in the thickness direction of the top cover sheet 400, and further, the buffer body 300 formed by the bottom wall of the weakened portion 200 being concave or arched in the thickness direction of the top cover sheet 400 has a gap between the side wall of the weakened portion 200.

[0095] The present embodiment sets a gap between the buffer body 300 and the side wall of the weakened portion 200, which avoids affecting the deformation resistance of the buffer body 300 after the buffer body 300 is connected to the side wall of the weakened portion 200, so as to ensure the stability of the buffer body 300 and the deformation resistance of the weakened portion 200.

[0096] Specifically, as shown in FIGS. 3, 4, 8, 13 and 17, in some embodiments, a plurality of buffer bodies 300 are continuously arranged along the trajectory direction of the weakened portion 200.

[0097] It should be noted that the plurality of buffer bodies 300 are continuously arranged to form an integrated buffer structure, and the buffer structure is arranged along the trajectory direction of the weakened portion 200, that is, the shape of the buffer body 300 is basically the same as the shape of the weakened portion 200. Since the side wall of the weakened portion 200 and the buffer body 300 have a gap, that is, along the trajectory direction of the weakened portion 200, the length of the buffer structure is less than the length of the weakened portion 200, and the width of the buffer structure is less than the width of the weakened portion 200.

[0098] By continuously arranging the weakened portion 200 along the trajectory direction of the buffer body 300, the stress and strain received by the weakened portion 200 can be buffered and released by the buffer body 300 along the trajectory direction of the weakened portion 200, so as to improve the deformation resistance of the weakened portion 200 and ensure the uniformity of the deformation resistance of each part of the weakened portion 200 along the trajectory direction of the weakened portion 200.

[0099] As shown in FIGS. 25 to 28, in some embodiments, a plurality of buffer bodies 300 are equidistantly arranged along the trajectory direction of the weakened portion 200.

[0100] The distance between the two adjacent buffer bodies 300 can be set according to actual conditions, and the number of buffer bodies 300 can be set according to actual conditions. It should be noted that the plurality of buffer bodies 300 are arranged along the trajectory direction of the weak portion 200, and the two ends close to the trajectory direction of the weak portion 200 are both provided with a buffer body 300, that is, the plurality of buffer bodies 300 are uniformly distributed along the trajectory of the weak portion 200, so as to ensure the uniformity of the deformation resistance of any two adjacent buffer bodies 300 along the trajectory of the weak portion 200, and avoid the situation that the stress is unevenly distributed in some local positions.

[0101] It should be noted that the trajectory direction of the weak portion 200 can be understood as the extension direction of the weak portion 200 in the plane of the explosion-proof valve body 120, such as the length direction.

[0102] As shown in FIGS. 25-28, in some embodiments, the shape of the buffer body 300 is approximately hemispherical. The buffer body 300 includes an inner wall surface (not shown in the figure) and an outer wall surface (not shown in the figure) oppositely arranged along the thickness direction of the top cover sheet 400, and both the inner wall surface and the outer wall surface are semicircular spherical surfaces.

[0103] In addition, by arranging the inner wall surface and the outer wall surface of the buffer body 300 as semicircular spherical surfaces, the buffer body 300 has a semispherical structure, which can uniformly buffer in various directions, so that the buffer body 300 can better buffer and release the stress and strain generated during the connection of the explosion-proof valve 100 and the hole wall of the mounting hole 410, and ensure the deformation resistance of the buffer body 300 and the weak portion 200.

[0104] It should be noted that the descriptions of hemispherical shape and semispherical surface are only for the purpose of describing that the inner wall surface and the outer wall surface of the buffer body 300 are spherical surfaces in this embodiment, and do not limit that they must be semicircular spherical surfaces. Of course, in some other embodiments of the present application, the inner wall surface and the outer wall surface of the buffer body 300 can also be ellipsoidal surfaces.

[0105] Referring to FIGS. 3-17, in some embodiments of the present application, the buffer body 300 is formed in a strip shape, which can be a straight strip or a curved strip. In this embodiment, the inner wall surface and the outer wall surface of the buffer body 300 are both arc surfaces, such as circular arc surfaces or elliptical arc surfaces. It can be understood that the longitudinal section of the buffer body 300 is arc-shaped.

[0106] Based on any one of the above embodiments, as shown in FIGS. 4, 9 and 13, in some embodiments of the present disclosure, the weak portion 200 has a middle line region in the width direction of the trajectory of the weak portion 200, and the plurality of buffer bodies 300 are arranged in the middle line region. That is, one weak portion 200 is provided with a plurality of buffer bodies 300, and the plurality of buffer bodies 300 are arranged at intervals along the length direction of the weak portion 200.

[0107] Of course, multiple buffers 300 arranged at a weak portion 200 can also be arranged at intervals along the width direction of the weak portion 200.

[0108] It can be understood that, in the width direction of the weak portion 200, by arranging the buffer 300 in the midline region of the weak portion 200, the uniformity of the stress and strain buffering of the buffer 300 on the explosion-proof valve body 120 is ensured, and the stability of the deformation resistance of the explosion-proof valve 100 is improved. Secondly, the multiple buffers 300 arranged at intervals can be arranged at equal intervals or at unequal intervals.

[0109] As shown in FIGS. 7 and 24, in some embodiments of the present disclosure, in the thickness direction of the explosion-proof valve 100, the weak portion 200 includes oppositely arranged first and second wall surfaces 310 and 320, and the buffer 300 is formed by local recessing of the first wall surface 310 toward the second wall surface 320.

[0110] It should be noted that, while the first wall surface 310 is locally recessed, the second wall surface 320 is locally protruded outward at the same time, that is, the first wall surface 310 and the second wall surface 320 always remain parallel to each other, so that the thickness of the buffer 300 is equal to the thickness of the weak portion 200, thereby enabling the buffer 300 to release the stress and strain generated between the explosion-proof valve 100 and the hole wall of the mounting hole 410 during the welding process, and ensuring the deformation resistance of the explosion-proof valve 100.

[0111] In addition, in some embodiments of the present disclosure, the buffer 300 is formed by locally arching the second wall surface 320 toward the first wall surface 310. It can be understood that, while the first wall surface 310 is locally arched, the second wall surface 320 is locally concave at the same time, so that the first wall surface 310 and the second wall surface 320 always remain parallel to each other, thereby ensuring the deformation resistance of the explosion-proof valve 100.

[0112] It should be noted that the first wall surface 310 and the outer wall surface of the buffer 300 are located on the same side, and together form the outer surface of the explosion-proof valve body 120. The second wall surface 320 and the inner wall surface of the buffer 300 are located on the same side, and together form the inner surface of the explosion-proof valve body 120. The thickness of the buffer 300 (i.e., the distance between the inner wall surface and the outer wall surface) is substantially the same as the thickness of the weak portion 200 (i.e., the distance between the first wall surface 310 and the second wall surface 320). The buffer 300 is formed by stamping process on the weak portion 200, and during stamping, the thickness of the buffer 300 may

[0113] As shown in FIGS. 7 and 24, in some embodiments of the present disclosure, the thickness of the mounting portion 110 is greater than the thickness of the explosion-proof valve body 120 in the thickness direction of the top cover sheet 400, so that the force connected between the explosion-proof valve body 120 and the mounting portion 110 is less than the force connected between the mounting portion 110 and the hole wall of the mounting hole 410.

[0114] That is, when the battery monomer disposed in the accommodation cavity is abused to make the gas generated in the inside reach a certain threshold, the thin portion 200 cracks due to the thin thickness of the thin portion 200 compared with the thickness of the explosion-proof valve body 120, and a part of the explosion-proof valve body 120 is turned over along the thin portion 200, thereby realizing the opening valve pressure relief function.

[0115] As shown in FIGS. 16 to 19, in some embodiments of the present disclosure, the thin portion 200 includes a first straight line segment 210 and a second straight line segment 220, the first straight line segment 210 and the second straight line segment 220 intersect to form an intersection point, and the intersection point is located at the center position of the explosion-proof valve body 120. The first straight line segment 210 and the second straight line segment 220 are respectively correspondingly provided with strip-shaped buffer bodies 300 along the midlines in the width direction, and the two buffer bodies 300 also intersect at the center position of the explosion-proof valve body 120.

[0116] It should be noted that the included angle between the first straight line segment 210 and the second straight line segment 220 can be specifically set according to actual conditions.

[0117] In the present embodiment, the first straight line segment 210 is arranged along the length direction of the explosion-proof valve body 120, that is, the length direction of the first straight line segment 210 is parallel to the length direction of the explosion-proof valve body 120, and the second straight line segment 220 is arranged along the width direction of the explosion-proof valve 100, that is, the length direction of the second straight line segment 220 is parallel to the width direction of the explosion-proof valve body 120.

[0118] It can be understood that the first straight line segment 210 is perpendicular to the second straight line segment 220, and the intersection point between the first straight line segment 210 and the second straight line segment 220 coincides with the midpoint of the first straight line segment 210 and the midpoint of the second straight line segment 220, so as to ensure the uniformity of the force received by the two ends of the first straight line segment 210 and the two ends of the second straight line segment 220 during the cracking of the thin portion 200, and improve the thin portion 200. That is, in the present embodiment, the shape of the thin portion 200 is a "cross", that is, when the thin portion 200 cracks under the action of pressure, the thin portion 200 first cracks at the intersection point between the first straight line segment 210 and the second straight line segment 220, and then cracks along the direction of the first straight line segment 210 and the second straight line segment 220 to form an exhaust port, so that the gas in the accommodation cavity can be discharged through the exhaust port, thereby realizing pressure relief.

[0119] As shown in FIGS. 8-11, in some embodiments of the present disclosure, only the first straight line segment 210 can be provided, and the first straight line segment 210 is arranged at the middle of the explosion-proof valve body, and both ends of the first straight line segment 210 are provided with two symmetric curve segments 230 to form the weak portion 200.

[0120] It should be noted that the structure of the curve segment 230 is the same as that of the weak portion 200, that is, the curve segment 230 also has a buffer body 300.

[0121] Specifically, the first straight line segment 210 is arranged along the length direction of the explosion-proof valve body 120, that is, the length direction of the first straight line segment 210 is parallel to the length direction of the explosion-proof valve body 120. Along the width direction of the explosion-proof valve body 120, the first straight line segment 210 is arranged at the middle line of the width direction of the explosion-proof valve body 120.

[0122] In addition, one end of the first straight line segment 210 is provided with two curve segments 230 symmetric to the first straight line segment 210, and the other end of the first straight line segment 210 is provided with two curve segments 230 symmetric to the first straight line segment 210. The curve segment 230 is arc-shaped or semicircular structure, and the convex surface of the curve segment 230 faces the extension direction of the first straight line segment 210, and the curve segments 230 arranged at both ends of the first straight line segment 210 are centrally symmetric to the midpoint of the first straight line segment 210.

[0123] As shown in FIGS. 12-15, in some embodiments of the present disclosure, the two ends of the curve segment 230 are respectively connected with the first straight line segment 210 and the second straight line segment 220, and the first straight line segment 210 and the second straight line segment 220 are parallel to each other to form a U-shaped notch segment. The U-shaped notch segment is two groups, and the opening ends of the two groups of U-shaped notch segments are reversely arranged at the two ends of the length direction of the explosion-proof valve body 120, and the curve segments 230 of the two groups of U-shaped notch segments are connected, and the whole forms the weak portion 200.

[0124] It should be noted that the two groups of U-shaped notch segments are symmetric with respect to the bisector in the width direction of the explosion-proof valve body 120, that is, the opening ends of the two groups of U-shaped notch segments face the length direction of the explosion-proof valve body 120.

[0125] Further, the length of the first straight line segment 210 is equal to the length of the second straight line segment 220, and the length direction of the first straight line segment 210 and the second straight line segment 220 is parallel to the length direction of the explosion-proof valve body 120.

[0126] As shown in FIGS. 3-6 and 20-23, in some embodiments of the present disclosure, the curve segments 230 of the two groups of U-shaped notch segments are arranged at the two ends of the explosion-proof valve body, respectively, the opening ends of the two groups of U-shaped notch segments are oppositely arranged, and one end of the two groups of U-shaped notch segments is connected by the first straight line segment 210 to form the weak portion 200.

[0127] Specifically, opposite ends of the two groups of U-shaped score segments are connected by the first straight line segment 210, and the other opposite ends of the two groups of U-shaped score segments are spaced apart from each other, the first straight line segment 210 is parallel to the second straight line segment 220, and the weak portion 200 provided in the embodiment is symmetrical with the bisector in the width direction of the explosion valve body 120 to ensure the uniformity and consistency of the stress of the two groups of U-shaped score segments. That is, when the two groups of U-shaped score segments are subjected to the gas pressure in the accommodating cavity, they can crack synchronously when the pressure reaches a threshold value.

[0128] Some embodiments of the present disclosure provide a battery pack comprising the battery cell described in any of the above embodiments.

[0129] The battery pack has the structure of the battery cell described in any of the above embodiments and its beneficial effects, which will not be repeated here.

[0130] Some embodiments of the present disclosure provide an electric device comprising the battery pack described in any of the above embodiments.

[0131] The electric device has the structure of the battery pack described in the above embodiments and its beneficial effects, which will not be repeated here.

[0132] In all the examples shown and described herein, any specific values should be interpreted as merely exemplary and not as a limitation, and thus, other examples of the example embodiments can have different values.

[0133] It should be noted that similar reference numbers and letters represent similar items in the following drawings, and thus, once an item is defined in one drawing, it need not be further defined and explained in subsequent drawings.

[0134] The above-described embodiments only express several implementation manners of the present disclosure, which are described in detail and specifically, but should not be understood as a limitation on the scope of the present disclosure. It should be noted that, for those skilled in the art, several modifications and improvements can be made without departing from the concept of the present disclosure, which are within the protection scope of the present disclosure. Industrial applicability

[0135] In summary, the present disclosure provides an explosion valve, a top cover assembly, a battery cell and a battery pack, which have simple overall structure, low cost, and can make the burst value of the explosion valve stable and improve the safety in use.

Claims

1. An explosion-proof valve applied to a battery monomer, wherein, The explosion-proof valve body (120) and the mounting portion (110) are provided; The mounting portion (110) is arranged at the outer periphery of the explosion-proof valve body (120) and is connected with the explosion-proof valve body (120); The explosion-proof valve body (120) is provided with a weak portion (200), and the weak portion (200) can be broken when the internal pressure of the battery monomer reaches a threshold value. At least part of the weak portion (200) is formed with a buffer body (300) in the thickness direction of the explosion-proof valve body (120) in the form of concave or arch.

2. The explosion relief valve of claim 1, wherein The thickness of the weak portion (200) is less than the thickness of the explosion-proof valve body (120). And / or, The weak portion (200) has a center line area located in the middle of the width direction of the weak portion (200), and the buffer body (300) is arranged in the center line area.

3. The explosion relief valve of claim 1, wherein, The weak portion (200) has opposite first and second wall surfaces (310) and (320) in the thickness direction of the explosion-proof valve body (120). The buffer body (300) is concave from the first wall surface (310) to the second wall surface (320), or the buffer body (300) is formed by arching from the second wall surface (320) to the first wall surface (310).

4. The explosion relief valve of claim 1, wherein, The buffer body (300) is arranged in a local area of the weak portion (200).

5. The explosion relief valve of claim 1, wherein The buffer body (300) has an inner wall surface and an outer wall surface, and both the inner wall surface and the outer wall surface are arc surfaces.

6. The explosion relief valve of claim 5, wherein, The inner wall surface and the outer wall surface are both circular arc surfaces.

7. The explosion relief valve of claim 1, wherein The buffer body (300) has opposite inner and outer wall surfaces, and both the inner and outer wall surfaces are spherical surfaces.

8. The explosion relief valve of claim 7, wherein, The inner and outer wall surfaces are both spherical surfaces.

9. The explosion relief valve of claim 1, wherein, One of the weak portions (200) is provided with a plurality of buffer bodies (300), and the plurality of buffer bodies (300) are arranged at intervals.

10. The explosion relief valve of claim 9, wherein, The plurality of buffer bodies (300) are arranged at equal intervals.

11. The explosion relief valve of claim 10, wherein, The plurality of buffer bodies (300) are arranged at intervals in the width direction or length direction of the weak portion (200).

12. The explosion relief valve of claim 10, wherein, The plurality of buffer bodies (300) are arranged at equal intervals in the width direction or length direction of the weak portion (200).

13. The explosion relief valve of claim 1, wherein, The thickness of the buffer body (300) is the same as the thickness of the weak portion (200).

14. The explosion relief valve of claim 1, wherein, The buffer body (300) is in the form of a strip or a hemisphere.

15. The explosion relief valve of claim 1, wherein, The thickness of the mounting portion (110) is greater than the thickness of the explosion-proof valve body (120).

16. The explosion relief valve of claim 1, wherein The weak portion (200) includes a first straight line segment (210) and a second straight line segment (220). The first straight line segment (210) intersects with the second straight line segment (220) to form an intersection point, and the intersection point is located at the center of the explosion-proof valve body (120).

17. The explosion relief valve of claim 1, wherein, The weak portion (200) includes a first curved segment and a second curved segment. The first curved segment (230) and the second curved segment are arranged in axial symmetry with the center line in the width direction of the explosion-proof valve body (120), and / or the first curved segment (230) and the second curved segment are arranged in axial symmetry with the center line in the length direction of the explosion-proof valve body (120).

18. A cap assembly characterized by, The explosion-proof valve comprises a top cover sheet (400) and the explosion-proof valve according to any one of claims 1-17. The top cover sheet (400) is provided with a mounting hole (410) penetrating through the top cover sheet (400). The explosion-proof valve is mounted in the mounting hole, and the mounting portion (110) is connected with the top cover sheet (400).

19. A battery cell, characterized by The top cover sheet top cover assembly comprises a shell (500) and the top cover sheet according to claim 18. The shell (500) has an open accommodating cavity. The top cover sheet (400) is arranged on the side of the shell (500) opening.

20. A battery pack, characterized by The battery monomer comprises the battery monomer according to claim 19.

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