Battery unit, battery pack and automobile

Abstract

The invention provides a battery unit, a battery pack and an automobile, and relates to the technical field of batteries, the battery unit comprises an electrode assembly, a battery shell, a cover assembly, a sealing element and an expandable structure, the electrode assembly comprises a first electrode, a second electrode and a separator arranged between the first electrode and the second electrode; an open part is arranged on the battery shell, and the battery shell can accommodate the electrode assembly and the electrolyte through the open part; the cover assembly is arranged on the open part and can be electrically connected with the first electrode; the sealing element is arranged between the battery shell and the cover assembly and is used for insulating the battery shell from the cover assembly; when the expandable structure is in the expanded state, the expandable structure can fill a gap between the seal and the cap assembly. The sealing effect between the sealing element and the cover assembly can be further enhanced by utilizing the expandable structure, and a gap between the sealing element and the cover assembly is eliminated, so that the leakage risk of the battery unit is reduced, and the reliability of the battery unit is improved.

Description

Technical Field

[0001] The present invention relates to the field of battery technology, and in particular to a battery unit, a battery pack and a car. Background Art

[0002] Cylindrical battery cells have the advantages of high energy density and stable working voltage, so that cylindrical battery cells are more and more widely used, especially for powering mobile devices. In the art, cylindrical battery cells are generally composed of a cylindrical metal shell, an electrode assembly, a cover assembly and a sealing gasket. The electrode assembly includes a positive electrode, a negative electrode and a diaphragm arranged between the positive electrode and the negative electrode. The cylindrical metal shell can be used to accommodate the electrode assembly and the electrolyte. One end of the cylindrical metal shell is provided with an opening for the electrode assembly to enter. The cover assembly is installed on the opening of the cylindrical metal shell and is insulated from the cylindrical metal shell through the sealing gasket. In the prior art, after the cylindrical metal shell, the cover assembly and the sealing gasket are folded and formed, although the sealing gasket can be crimped between the cylindrical metal shell and the cover assembly, there is a certain shape difference between the folded sealing gasket and the cover assembly, so that the sealing gasket cannot fit tightly on the cover assembly, thereby generating a gap between the sealing gasket and the cover assembly. When the internal pressure of the cylindrical battery cell increases, the gap between the sealing gasket and the cover assembly is prone to form a leakage channel, thereby increasing the risk of leakage. Therefore, how to eliminate the gap between the sealing gasket and the cover assembly to reduce the leakage risk of the battery cell has become a technical problem that needs to be solved urgently. Summary of the invention

[0003] In order to overcome the above-mentioned defects of the prior art, the technical problem to be solved by the embodiments of the present invention is to provide a battery cell, a battery pack and a car, which are used to reduce the leakage risk of the battery cell.

[0004] The above-mentioned object of the present invention can be achieved by adopting the following technical solutions. The present invention provides a battery unit, comprising:

[0005] an electrode assembly, the electrode assembly comprising a first electrode, a second electrode, and a separator disposed between the first electrode and the second electrode;

[0006] A battery housing, wherein the battery housing is provided with an opening portion, and the battery housing can accommodate the electrode assembly and the electrolyte through the opening portion;

[0007] a cover assembly, the cover assembly being disposed at the open portion and being electrically connected to the first electrode;

[0008] A sealing member, the sealing member being disposed between the battery housing and the cover assembly and being used to insulate the battery housing and the cover assembly;

[0009] An inflatable structure, the inflatable structure includes a state to be inflated and an inflated state. When the inflatable structure is in the state to be inflated, the inflatable structure is arranged between the seal and the cover assembly; when the inflatable structure is in the inflated state, the inflatable structure can fill the gap between the seal and the cover assembly.

[0010] In a preferred embodiment of the present invention, the expandable structure comprises a foam layer, and when the foam layer is in the state to be expanded, the foam layer can be disposed on the sealing member.

[0011] In a preferred embodiment of the present invention, the foaming layer is formed by a foaming agent.

[0012] In a preferred embodiment of the present invention, the foaming agent foams at a preset temperature to form the expanded state.

[0013] In a preferred embodiment of the present invention, the foaming agent includes one of ADCA, OBSH, DPT or Inorganic.

[0014] In a preferred embodiment of the present invention, the foaming agent includes ADCA, and the preset temperature is 181°C to 198°C.

[0015] In a preferred embodiment of the present invention, the seal comprises a sealing gasket having an outer sealing surface facing the battery housing and an inner sealing surface facing the cover assembly, and the expandable structure is disposed on at least a partial area of ​​the inner sealing surface.

[0016] In a preferred embodiment of the present invention, the sealing member is formed by insulating elastic material.

[0017] In a preferred embodiment of the present invention, the insulating elastic material includes polybutylene terephthalate.

[0018] In a preferred embodiment of the present invention, the sealing gasket includes a ready-to-install state and an installed state, and the sealing gasket is arranged between the battery housing and the cover assembly to form the installed state;

[0019] When the sealing gasket is in the state to be installed, the sealing gasket comprises:

[0020] A first part, the first part is extended along the axial direction of the battery housing;

[0021] A second portion connected to the first portion and extending along the radial direction of the battery housing toward the central axis of the battery housing;

[0022] The third part is connected to the second part and extends away from the first part along the axial direction of the battery shell. The radial dimension of the third part is smaller than the radial dimension of the first part.

[0023] In a preferred embodiment of the present invention, the foaming layer is disposed on the inner side of the first part.

[0024] In a preferred embodiment of the present invention, the foaming layer is disposed in a middle area of ​​the inner side surface of the first portion or the foaming layer is disposed in a bending area of ​​the inner side surface of the first portion.

[0025] In a preferred embodiment of the present invention, a containing structure is provided on the inner side surface of the first part, and the foaming layer is arranged in the containing structure.

[0026] In a preferred embodiment of the present invention, the containing structure includes at least one containing groove arranged on the inner side surface of the first part, and the containing groove is used to contain a foaming agent to form the foaming layer.

[0027] In a preferred embodiment of the present invention, along the circumference of the battery housing, at least a portion of the outer surface of the battery housing is bent inward to form a curling portion, and the curling portion abuts against the sealing member.

[0028] In a preferred embodiment of the present invention, the curling portion abuts against an outer side surface of the first portion and / or an outer side surface of the second portion.

[0029] In a preferred embodiment of the present invention, along the circumference of the battery casing, the outer end of the open portion is bent inward to form a clamping portion, and during the bending process of the clamping portion, at least a portion of the first portion is synchronously bent inward with the clamping portion and abuts against the cover assembly to form a bent portion.

[0030] In a preferred embodiment of the present invention, the cover assembly includes a top cover and a safety vent, the outer peripheral edge of the safety vent is folded inward to wrap the edge of the top cover, and the safety vent is used to rupture to discharge gas when the pressure in the battery cell exceeds a preset value.

[0031] In a preferred embodiment of the present invention, the battery cell further comprises a limiting structure, and the limiting structure is used to limit the sealing member and the cover assembly along the radial direction of the battery cell.

[0032] In a preferred embodiment of the present invention, the limiting structure includes a first concave-convex structure arranged on the inner side surface of the second part, and a second concave-convex structure arranged on the outer side surface of the safety vent, and the first concave-convex structure and the second concave-convex structure are matched and connected.

[0033] In a preferred embodiment of the present invention, the battery cell further comprises a current interrupting element, which electrically connects the safety vent and the first electrode, and is configured to rupture to cut off the electrical connection when the pressure within the battery cell exceeds a preset value.

[0034] In a preferred embodiment of the present invention, the sealing gasket also includes a fourth part, which is connected to the third part and extends along the radial direction of the battery shell toward the central axis of the battery shell, and the current interruption element is arranged on the fourth part.

[0035] In a preferred embodiment of the present invention, the battery unit further comprises a CID pad disposed on the fourth portion, wherein the CID pad wraps around the outer peripheral edge of the current interruption element to block contact between the current interruption element and the safety vent.

[0036] The present invention also provides a battery pack, comprising at least one of the aforementioned battery cells.

[0037] The present invention also provides a car, comprising at least one of the aforementioned battery packs.

[0038] The technical solution of the present invention has the following significant beneficial effects:

[0039] When the battery cell of the present invention is used, the battery shell can accommodate the electrode assembly and the electrolyte through the open portion, wherein an opening is formed in the open portion for the electrode assembly and the electrolyte to enter the battery shell. The cover assembly can be mounted on the open portion by folding the battery shell and the seal, and the seal can be used to seal and insulate between the cover assembly and the battery shell, thereby ensuring the reliability of the battery cell.

[0040] Since the seal deforms during the folding process, there is a difference in shape between the seal and the cover assembly, which makes it impossible for the seal to fit tightly on the cover assembly, resulting in a gap between the seal and the cover assembly. When the pressure in the battery cell increases, the gap between the seal and the cover assembly easily forms a leakage channel, thereby increasing the risk of leakage.

[0041] In order to solve the above problems, the present application also provides an expandable structure, which includes a state to be expanded and an expanded state. When the expandable structure is in the state to be expanded, the expandable structure can be arranged between the seal and the cover assembly, thereby reducing the difficulty of setting the expandable structure. Moreover, when the expandable structure is in the expanded state, the expandable structure can fill the gap between the seal and the cover assembly, so that the use of the expandable structure can further enhance the sealing effect between the seal and the cover assembly, eliminate the gap between the seal and the cover assembly, thereby reducing the risk of leakage of the battery cell and improving the reliability of the battery cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0043] The accompanying drawings described herein are only for explanation purposes and are not intended to limit the scope of the present invention in any way. In addition, the shapes and proportional dimensions of the various components in the figures are only schematic, used to help understand the present invention, and are not specifically limited to the shapes and proportional dimensions of the various components of the present invention. Those skilled in the art can select various possible shapes and proportional dimensions to implement the present invention according to the teachings of the present invention.

[0044] Figure 1 A three-dimensional structural diagram of an embodiment of the battery unit of the present invention;

[0045] Figure 2 A three-dimensional cross-sectional view of an embodiment of the battery unit of the present invention;

[0046] Figure 3 A front cross-sectional view of an embodiment of the battery unit of the present invention;

[0047] Figure 4 A three-dimensional structural diagram of an embodiment of the sealing gasket of the present invention;

[0048] Figure 5 A partial cross-sectional side view of an embodiment of the sealing gasket of the present invention;

[0049] Figure 6 A side partial cross-sectional view of a first embodiment of the foaming layer of the present invention;

[0050] Figure 7 A side partial cross-sectional view of a second embodiment of the foaming layer of the present invention;

[0051] Figure 8 A partial side cross-sectional view of a third embodiment of the foaming layer of the present invention;

[0052] Fig. 9 A side partial cross-sectional view of a fourth embodiment of the foaming layer of the present invention;

[0053] Fig.10 A partial cross-sectional side view of an embodiment of the expandable structure of the present invention in a state to be expanded;

[0054] Fig.11 A partial cross-sectional side view of an embodiment of the inflatable structure of the present invention in an inflated state;

[0055] Fig.12 A three-dimensional structural diagram of an embodiment of the battery pack of the present invention;

[0056] Fig.13 The present invention is a three-dimensional perspective structural diagram of an embodiment of the automobile.

[0057] Reference numerals in the above drawings:

[0058] 1. Battery unit;

[0059] 10. electrode assembly; 11. first uncoated portion; 12. second uncoated portion;

[0060] 20. battery housing; 21. curling portion; 22. clamping portion;

[0061] 30. Cover assembly; 31. Top cover; 32. Safety vent; 321. Second concave-convex structure;

[0062] 40. sealing member; 41. first part; 42. second part; 421. first concave-convex structure; 43. third part; 44. fourth part;

[0063] 50. current collector; 51. lead;

[0064] 60. Current interruption element;

[0065] 70. expandable structure; 71. foaming layer;

[0066] 80. Gap;

[0067] 2. Box shell;

[0068] 3. Battery pack;

[0069] 5. Car. DETAILED DESCRIPTION

[0070] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions 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 of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0071] Implementation Method 1

[0072] Please refer to Figures 1 to 12 As shown, a battery cell 1 is provided in an embodiment of the present invention, which includes at least an electrode assembly 10, a battery casing 20, a cover assembly 30, a seal 40 and an inflatable structure 70, wherein the electrode assembly 10 includes a first electrode, a second electrode and a separator arranged between the first electrode and the second electrode; an opening is provided on the battery casing 20, and the battery casing 20 can accommodate the electrode assembly 10 and an electrolyte through the opening; the cover assembly 30 is arranged in the opening and can be electrically connected to the first electrode; the seal 40 is arranged between the battery casing 20 and the cover assembly 30, and is used to insulate the battery casing 20 and the cover assembly 30, and the inflatable structure 70 includes a state to be expanded and a state to be expanded, when the inflatable structure 70 is in the state to be expanded, the inflatable structure 70 is arranged between the seal 40 and the cover assembly 30; when the inflatable structure 70 is in the expanded state, the inflatable structure 70 can fill the gap 80 between the seal 40 and the cover assembly 30.

[0073] In general, when the battery cell 1 of the present invention is used, Figure 1 , Figure 2 and Figure 3 In the illustrated embodiment, the battery case 20 can accommodate the electrode assembly 10 and the electrolyte through the open portion, wherein an opening is formed in the open portion for the electrode assembly 10 and the electrolyte to enter the battery case 20. The cap assembly 30 can be mounted on the open portion by folding the battery case 20 and the seal 40, and the seal 40 can be used to seal and insulate between the cap assembly 30 and the battery case 20, thereby ensuring the reliability of the battery cell 1.

[0074] like Figure 3 , Figure 4 , Figure 5 , Figure 6 and Fig.11 In the embodiment shown, since the seal 40 is deformed during the folding process, a shape difference occurs between the seal 40 and the cap assembly 30, so that the seal 40 cannot fit tightly on the cap assembly 30, thereby generating a gap 80 between the seal 40 and the cap assembly 30. When the pressure in the battery cell 1 increases, the gap 80 between the seal 40 and the cap assembly 30 is likely to form a leakage channel, thereby increasing the risk of leakage.

[0075] In order to solve the above problems, the present application also provides an expandable structure 70, such as Fig.10 and Fig.11 In the illustrated embodiment, the inflatable structure 70 includes a ready-to-inflate state and an inflated state. When the inflatable structure 70 is in the ready-to-inflate state, the inflatable structure 70 can be disposed between the seal 40 and the cover assembly 30 , thereby reducing the difficulty of disposing the inflatable structure 70 .

[0076] Moreover, when the inflatable structure 70 is in an inflated state, the inflatable structure 70 can fill the gap 80 between the seal 40 and the cover assembly 30, so that the inflatable structure 70 can further enhance the sealing effect between the seal 40 and the cover assembly 30, eliminate the gap 80 between the seal 40 and the cover assembly 30, thereby reducing the leakage risk of the battery cell 1 and improving the reliability of the battery cell 1.

[0077] In an embodiment of the present invention, the separator includes a diaphragm, and the first electrode, the diaphragm, and the second electrode are stacked and wound to form the electrode assembly 10. By arranging the diaphragm between the first electrode and the second electrode, the diaphragm can play an insulating role.

[0078] The material of the diaphragm is non-conductive, and the user can reasonably select the material of the diaphragm without restriction. The diaphragm separates the first electrode from the second electrode to prevent the two electrodes from contacting and short-circuiting. In addition, the diaphragm also has the function of allowing electrolyte ions in the electrolyte to pass through.

[0079] Further, such as Figure 2 and Figure 3 In the illustrated embodiment, a first non-coating portion 11 and a second non-coating portion 12 are respectively formed at both ends of the electrode assembly 10 .

[0080] Specifically, at least a portion of the first electrode forms a first uncoated portion 11, and at least a portion of the second electrode forms a second uncoated portion 12. The first uncoated portion 11 can be used to be electrically connected to the cover assembly 30, and the second uncoated portion 12 can be used to be electrically connected to the battery housing 20, so that the cover assembly 30 and the battery housing 20 serve as the positive and negative electrodes of the battery cell 1, respectively.

[0081] Of course, in other feasible embodiments, designers can adjust the specific structure of the electrode assembly 10 according to usage requirements, and no specific limitations are made here.

[0082] In an embodiment of the present invention, Fig.10 and Fig.11 In the illustrated embodiment, the expandable structure 70 includes a foam layer 71 , and the foam layer 71 can be disposed on the sealing member 40 when the foam layer 71 is in a state to be expanded.

[0083] By utilizing the foaming layer 71 as the expandable structure 70, when the foaming layer 71 is not foamed, that is, when the foaming layer 71 is in a state to be expanded, the foaming layer 71 can be set thinner, which is convenient for being set between the seal 40 and the cover assembly 30, and reduces the encroachment on the space inside the battery cell 1, thereby not easily increasing the volume of the battery cell 1.

[0084] Moreover, when the foaming layer 71 is foamed, that is, when the foaming layer 71 is in an expanded state, the volume of the foaming layer 71 increases and can automatically fill the gap 80 between the seal 40 and the cover assembly 30, thereby eliminating the gap 80 between the seal 40 and the cover assembly 30 and having a better filling and sealing effect.

[0085] Specifically, the foaming layer 71 is formed by a foaming agent. Further, the foaming agent foams at a preset temperature to form an expanded state.

[0086] By making the foaming agent foam at a preset temperature, the foaming process of the foaming agent can be controlled by controlling the ambient temperature, thereby preventing the foaming agent from foaming in advance and affecting the production of the battery unit 1.

[0087] The designer can adjust the specific material and foaming method of the foaming agent according to the use requirements, and no specific restrictions are made here. For example, the foaming agent includes one of ADCA, OBSH, DPT or Inorganic. Among them, ADCA is an azodicarbonamide foaming agent. OBSH is a 4,4'-di-sulfonylhydrazide diphenyl ether foaming agent. DPT is an N,N-dinitrosopentamethylenetetramine foaming agent. Inorganic is an inorganic foaming agent.

[0088] Preferably, the foaming agent comprises ADCA. More preferably, the preset temperature is 181°C to 198°C.

[0089] Of course, in other feasible embodiments, designers can adjust the material of the foaming agent and the range of the preset temperature according to usage requirements. For example, the foaming agent can also be a high-temperature foaming agent, and no specific restrictions are made here.

[0090] In an embodiment of the present invention, Figure 4 In the illustrated embodiment, the seal 40 includes a gasket having an outer sealing surface facing the battery housing 20 and an inner sealing surface facing the lid assembly 30 , and the expandable structure 70 is disposed on at least a portion of the inner sealing surface.

[0091] Specifically, the expandable structure 70 includes a foaming layer 71. By coating a foaming agent on at least a portion of the inner sealing surface, the foaming layer 71 can be installed between the battery housing 20 and the cover assembly 30 together with the sealing gasket, thereby improving the installation efficiency of the foaming layer 71 and reducing the difficulty of implementing the foaming layer 71.

[0092] In the embodiment of the present invention, the seal 40 is formed by an insulating elastic material. By using the insulating elastic material to manufacture the seal 40, the seal 40 can play an insulating role between the battery housing 20 and the cover assembly 30. In addition, the seal 40 has a certain elasticity, and the seal 40 can be folded together with the battery housing 20 so that the cover assembly 30 is installed on the open portion.

[0093] Designers can adjust the specific material of the sealing member 40 according to the use requirements, and no specific limitation is made here. Preferably, the insulating elastic material includes polybutylene terephthalate.

[0094] In an embodiment of the present invention, Figure 3 , Fig.10 and Fig.11 In the embodiment shown, the sealing gasket includes a ready-to-install state and an installed state, and the sealing gasket is arranged between the battery housing 20 and the cover assembly 30 to form the installed state. Figure 4 and Figure 5 The gasket in the is ready to be installed.

[0095] Furthermore, when the gasket is in the state of being installed, Figure 5 and Figure 6 In the embodiment shown, the sealing gasket includes at least a first portion 41, a second portion 42, and a third portion 43. The first portion 41 extends along the axial direction of the battery housing 20; the second portion 42 is connected to the first portion 41 and extends along the radial direction of the battery housing 20 toward the central axis of the battery housing 20; the third portion 43 is connected to the second portion 42 and extends away from the first portion 41 along the axial direction of the battery housing 20, and the radial dimension of the third portion 43 is smaller than the radial dimension of the first portion 41.

[0096] The first portion 41 and the second portion 42 cooperate to form a groove-shaped structure, so that the cover assembly 30 can be placed on the second portion 42 and radially limited by the first portion 41 .

[0097] It should be noted that, since the first portion 41 needs to be folded inwardly together with the battery housing 20, the first portion 41 will be deformed during the folding process, so that the bending position of the inner side surface of the first portion 41 and the cover assembly 30 are likely to have a shape difference and generate a gap 80. The second portion 42 does not undergo a folding operation, so that the second portion 42 can be attached to the cover assembly 30. Therefore, how to better arrange the foaming layer 71 to fill the sealing gap 80 has become a technical problem that needs to be solved.

[0098] In one possible embodiment, if Figure 6In the illustrated embodiment, the foam layer 71 is disposed on the sealing gasket so that the foam layer 71 can be used to fill and seal the gap 80 around the sealing gasket.

[0099] In another possible embodiment, if Figure 7 In the illustrated embodiment, the foam layer 71 is disposed on the inner sealing surface of the sealing gasket, so that the gap 80 between the sealing gasket and the cover assembly 30 can be filled and sealed by the foam layer 71 .

[0100] Specifically, the foaming layer 71 is disposed on the inner side of the first portion 41. By disposing the foaming layer 71 on the inner side of the first portion 41, the foaming layer 71 can fill the gap 80 between the first portion 41 and the cover assembly 30 after foaming, thereby playing a sealing role and reducing the influence of the foaming layer 71 on the cover assembly 30.

[0101] Preferably, Figure 8 In the illustrated embodiment, the foaming layer 71 is disposed in the middle area of ​​the inner side surface of the first portion 41. By disposing the foaming layer 71 in the middle area of ​​the inner side surface of the first portion 41, the foaming layer 71 can foam in the middle area of ​​the inner side surface of the first portion 41 and overflow to both sides, thereby being able to better fill the gap 80 between the first portion 41 and the cover assembly 30.

[0102] Or, if Fig. 9 In the embodiment shown, the foam layer 71 is disposed in the bending region of the inner side of the first portion 41. Since the bending region has a large deformation amount, the bending region of the inner side of the first portion 41 and the cover assembly 30 are easily different in shape and a gap 80 is formed.

[0103] Therefore, by setting the foaming layer 71 in the bending area of ​​the inner side surface of the first part 41, the foaming layer 71 can be foamed in the bending area specifically, thereby improving the filling and sealing effect of the foaming layer 71 on the bending area and helping to reduce the amount of the foaming layer 71 used.

[0104] In the embodiment of the present invention, a containing structure (not shown) is provided on the inner side of the first part 41, and the foaming layer 71 is disposed in the containing structure. By disposing the containing structure on the inner side of the first part 41, the foaming layer 71 can be placed in the containing structure, and the foaming layer 71 is prevented from protruding on the inner side of the first part 41, thereby preventing the sealing gasket and the cover assembly 30 from affecting the foaming layer 71 during the installation process, and improving the setting accuracy of the foaming layer 71.

[0105] Furthermore, by controlling the capacity of the containing structure, the usage of the foaming layer 71 can also be controlled to avoid excessive or insufficient usage of the foaming layer 71, thereby improving the foaming stability of the foaming layer 71 and ensuring the sealing effect of the foaming layer 71.

[0106] Specifically, the containing structure includes at least one containing groove annularly arranged on the inner side of the first portion 41, and the containing groove is used to contain the foaming agent to form the foaming layer 71. Designers can adjust the specific structure, number and arrangement of the containing groove according to the use requirements, and no specific limitation is made here.

[0107] In the art, after the seal 40 is injection molded, coal tar may be coated on the seal 40 to enhance the sealing ability of the seal 40 .

[0108] When the surface of the seal 40 is not evenly coated with coal tar, the sealing performance of the seal 40 will be reduced, and after the seal 40 is folded together with the battery housing 20, a gap 80 will still be generated between the seal 40 and the cover assembly 30 due to the shape difference, thereby increasing the risk of leakage.

[0109] The present invention can eliminate the gap 80 between the seal 40 and the cover assembly 30 by providing the foaming layer 71, thereby solving the leakage problem. Therefore, the seal 40 of the present invention does not need to be coated with coal tar, thereby preventing the coal tar on the seal 40 from remaining on the transfer equipment.

[0110] In an embodiment of the present invention, Figure 2 , Figure 3 , Fig.10 and Fig.11 In the illustrated embodiment, along the circumference of the battery housing 20 , at least a portion of the outer surface of the battery housing 20 is bent inward to form a curling portion 21 , and the curling portion 21 abuts against the sealing member 40 .

[0111] By bending at least part of the outer surface of the battery housing 20 inward to form a curling portion 21, the curling portion 21 is integrated with the battery housing 20, thereby improving the structural strength of the curling portion 21, reducing the processing difficulty of the curling portion 21, and improving manufacturing efficiency.

[0112] Furthermore, by making the curling portion 21 abut against the outer surface of the sealing member 40 , the curling portion 21 can limit the sealing member 40 , thereby improving the installation accuracy of the sealing member 40 .

[0113] Specifically, Fig.10 and Fig.11 In the illustrated embodiment, the curled edge portion 21 abuts against an outer side surface of the first portion 41 and / or an outer side surface of the second portion 42 .

[0114] Preferably, the curling portion 21 abuts against the outer side surface of the first portion 41 and the outer side surface of the second portion 42. The curling portion 21 can limit the first portion 41 and the second portion 42, so that the sealing gasket can be more stably arranged in the battery housing 20.

[0115] Furthermore, along the circumference of the battery housing 20, as Figure 1 and Figure 2 In the illustrated embodiment, the outer end of the open portion is bent inward to form the clamping portion 22. During the bending process of the clamping portion 22, at least part of the first portion 41 is bent inward synchronously with the clamping portion 22 and abuts against the cover assembly 30 to form a bent portion.

[0116] Specifically, the clamping portion 22 and the curling portion 21 are arranged opposite to each other on both sides of the outer peripheral edge of the cover assembly 30. The clamping portion 22 and the curling portion 21 cooperate with each other, so that the sealing gasket can be pressed on the cover assembly 30, and the sealing gasket wraps the outer peripheral edge of the cover assembly 30, and then the battery housing 20 and the cover assembly 30 can be insulated by the sealing gasket.

[0117] In an embodiment of the present invention, Fig.10 and Fig.11 In the illustrated embodiment, the cap assembly 30 includes a top cover 31 and a safety vent 32, the peripheral edge of the safety vent 32 is folded inward to wrap the edge of the top cover 31, and the safety vent 32 is used to rupture to discharge gas when the pressure in the battery cell 1 exceeds a preset value.

[0118] Furthermore, the battery cell 1 also includes a limiting structure, which is used to limit the seal 40 and the cover assembly 30 along the radial direction of the battery cell 1.

[0119] Specifically, Figure 8 and Fig. 9 In the illustrated embodiment, the limiting structure includes a first concave-convex structure 421 disposed on the inner side of the second portion 42 and a second concave-convex structure 321 disposed on the outer side of the safety vent 32 , and the first concave-convex structure 421 and the second concave-convex structure 321 are matched and connected.

[0120] The first concavo-convex structure 421 and the second concavo-convex structure 321 cooperate with each other, thereby improving the structural stability between the safety vent portion 32 and the second portion 42 and preventing the cover assembly 30 from moving.

[0121] In a feasible embodiment, the first concave-convex structure 421 is a convex structure, and the second concave-convex structure 321 is a concave structure, and the convex structure and the concave structure can be matched and connected.

[0122] In another feasible embodiment, the first concave-convex structure 421 is a concave structure, and the second concave-convex structure 321 is a convex structure, and the convex structure and the concave structure can be matched and connected.

[0123] Of course, in other feasible embodiments, designers can adjust the specific structures of the first concave-convex structure 421 and the second concave-convex structure 321 according to usage requirements, and no specific limitation is made here.

[0124] In an embodiment of the present invention, Figure 3 In the illustrated embodiment, the battery cell 1 further comprises a current interruption element 60 , which electrically connects the safety vent 32 and the first electrode, and is configured to rupture to cut off the electrical connection when the pressure in the battery cell 1 exceeds a preset value.

[0125] In a feasible embodiment, the first electrode is a positive electrode, and the second electrode is a negative electrode. At least part of the first electrode forms the first non-coating portion 11, a current collector 50 is further provided in the battery housing 20, the current collector 50 is electrically connected to the first non-coating portion 11, and a lead 51 is further provided on the current collector 50, one end surface of the current interruption element 60 is electrically connected to the current collector 50 through the lead 51, and the other end surface of the current interruption element 60 is welded to the safety vent 32.

[0126] When the pressure in the battery cell 1 exceeds the preset value, the safety vent 32 will rupture to exhaust gas, and during the rupture of the safety vent 32, the safety vent 32 will separate from the current interruption element 60 to stop power supply, thereby ensuring the safety of the battery cell 1. Designers can adjust the preset value according to usage needs, and no specific numerical limit is imposed here.

[0127] In an embodiment of the present invention, the sealing gasket further includes a fourth portion 44 , which is connected to the third portion 43 and extends radially toward the central axis of the battery housing 20 , and the current interruption element 60 is disposed on the fourth portion 44 .

[0128] Furthermore, the battery unit 1 further includes a CID pad disposed on the fourth portion 44, the CID pad wrapping the outer peripheral edge of the current interruption element 60 to block the contact between the current interruption element 60 and the safety vent 32. CID is the abbreviation of current interrupt device, referring to the current interruption element 60 mentioned above.

[0129] Specifically, the fourth portion 44 is disposed around the third portion 43. The fourth portion 44 may be disposed continuously or discontinuously, which is not specifically limited herein.

[0130] Of course, in other feasible embodiments, designers can adjust the specific structure of the fourth part 44 according to usage requirements, and no specific limitation is made here.

[0131] Implementation Method 2

[0132] Please refer to Fig.12As shown, a battery pack 3 is further provided in an embodiment of the present invention. The battery pack 3 includes at least one battery cell 1 as described in the first embodiment.

[0133] The specific structure, working principle and beneficial effects of the battery cell 1 are the same as those in the first embodiment, and are not described in detail here. The battery pack 3 can enhance the sealing effect between the seal 40 and the cover assembly 30 by using the battery cell 1 described in the first embodiment, eliminate the gap 80 between the seal 40 and the cover assembly 30, thereby reducing the leakage risk of the battery cell 1 and improving the reliability of the battery pack 3.

[0134] Specifically, the battery pack 3 includes a box shell 2 , and a plurality of battery cells 1 are provided. The plurality of battery cells 1 are arranged in the box shell 2 at intervals.

[0135] The designer can adjust the specific shape of the box shell 2 according to the use requirements, and no specific limitation is made here. Preferably, the box shell 2 is configured as a rectangular parallelepiped.

[0136] Implementation Method 3

[0137] Please refer to Fig.13 As shown, an embodiment of the present invention further provides a car 5, which includes at least one battery pack 3 as described in Embodiment 2. The specific structure, working principle and beneficial effects of the battery pack 3 are the same as those in Embodiment 2, and will not be repeated here.

[0138] All articles and references disclosed, including patent applications and publications, are incorporated herein by reference for various purposes. The term "consisting essentially of ... " describing a combination should include determined elements, ingredients, parts or steps and other elements, ingredients, parts or steps that do not substantially affect the basic novel features of the combination. The use of the terms "comprising" or "including" to describe the combination of elements, ingredients, parts or steps here also contemplates the implementation method consisting essentially of these elements, ingredients, parts or steps. Here, by using the term "may", it is intended to illustrate that any attribute described that "may" includes is optional. Multiple elements, ingredients, parts or steps can be provided by a single integrated element, ingredient, part or step. Alternatively, a single integrated element, ingredient, part or step can be divided into separate multiple elements, ingredients, parts or steps. The disclosure "one" or "one" used to describe an element, ingredient, part or step is not said to exclude other elements, ingredients, parts or steps.

[0139] Each embodiment in this specification is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same and similar parts between the embodiments can be referred to each other. The above embodiments are only for illustrating the technical concept and features of the present invention. The purpose is to enable people familiar with this technology to understand the content of the present invention and implement it accordingly, and it cannot be used to limit the scope of protection of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A battery cell, characterized in that: include: an electrode assembly, the electrode assembly comprising a first electrode, a second electrode, and a separator disposed between the first electrode and the second electrode; A battery housing, wherein the battery housing is provided with an opening portion, and the battery housing can accommodate the electrode assembly and the electrolyte through the opening portion; a cover assembly, the cover assembly being disposed at the open portion and being electrically connected to the first electrode; A sealing member, the sealing member being disposed between the battery housing and the cover assembly and being used to insulate the battery housing and the cover assembly; An inflatable structure, the inflatable structure includes a state to be inflated and an inflated state. When the inflatable structure is in the state to be inflated, the inflatable structure is arranged between the seal and the cover assembly; when the inflatable structure is in the inflated state, the inflatable structure can fill the gap between the seal and the cover assembly.

2. The battery cell according to claim 1, wherein: The expandable structure includes a foam layer, and when the foam layer is in the state to be expanded, the foam layer can be disposed on the sealing member.

3. The battery cell according to claim 2, characterized in that The foaming layer is formed by a foaming agent.

4. The battery cell according to claim 3, characterized in that The foaming agent foams at a preset temperature to form the expanded state.

5. The battery cell according to claim 4, characterized in that The foaming agent includes one of ADCA, OBSH, DPT or Inorganic.

6. The battery cell according to claim 5, characterized in that The foaming agent includes ADCA, and the preset temperature is 181° C. to 198° C.

7. The battery cell according to claim 2, wherein: The sealing member comprises a sealing gasket having an outer sealing surface disposed facing the battery housing and an inner sealing surface disposed facing the cover assembly, and the expandable structure is disposed at least on a partial area of ​​the inner sealing surface.

8. The battery cell according to claim 7, wherein: The sealing member is formed of an insulating elastic material.

9. The battery cell according to claim 8, characterized in that The insulating elastic material includes polybutylene terephthalate.

10. The battery cell according to claim 7, wherein: The sealing gasket includes a ready-to-install state and an installed state, and the sealing gasket is arranged between the battery housing and the cover assembly to form the installed state; When the sealing gasket is in the state to be installed, the sealing gasket comprises: A first part, the first part is extended along the axial direction of the battery housing; A second portion connected to the first portion and extending along the radial direction of the battery housing toward the central axis of the battery housing; The third part is connected to the second part and extends away from the first part along the axial direction of the battery shell. The radial dimension of the third part is smaller than the radial dimension of the first part.

11. The battery cell according to claim 10, wherein: The foaming layer is arranged on the inner side of the first part.

12. The battery cell according to claim 11, wherein: The foaming layer is disposed in a middle area of ​​the inner side surface of the first portion or the foaming layer is disposed in a bending area of ​​the inner side surface of the first portion.

13. The battery cell according to claim 11, wherein: The inner side surface of the first part is provided with a containing structure, and the foaming layer is arranged in the containing structure.

14. The battery cell according to claim 13, wherein: The containing structure comprises at least one containing groove arranged in a ring shape on the inner side surface of the first part, and the containing groove is used to contain a foaming agent to form the foaming layer.

15. The battery cell according to claim 10, wherein: Along the circumference of the battery shell, at least a portion of the outer surface of the battery shell is bent inward to form a curling portion, and the curling portion abuts against the sealing member.

16. The battery cell according to claim 15, characterized in that The curling portion abuts against an outer side surface of the first portion and / or an outer side surface of the second portion.

17. The battery cell according to claim 10, wherein: Along the circumference of the battery housing, the outer end of the open portion is bent inward to form a clamping portion. During the bending process of the clamping portion, at least part of the first portion is bent inward synchronously with the clamping portion and abuts against the cover assembly to form a bent portion.

18. The battery cell according to claim 10, wherein: The cap assembly includes a top cover and a safety vent, wherein the outer peripheral edge of the safety vent is folded inward to wrap the edge of the top cover, and the safety vent is used to rupture to discharge gas when the pressure in the battery cell exceeds a preset value.

19. The battery cell according to claim 18, wherein: The battery cell further includes a limiting structure for limiting the sealing member and the cover assembly along a radial direction of the battery cell.

20. The battery cell according to claim 19, wherein: The limiting structure includes a first concave-convex structure arranged on the inner side surface of the second part, and a second concave-convex structure arranged on the outer side surface of the safety vent, and the first concave-convex structure and the second concave-convex structure are matched and connected.

21. The battery cell according to claim 18, wherein: The battery cell further includes a current interruption element electrically connecting the safety vent and the first electrode, the current interruption element being configured to rupture to cut off electrical connection when pressure within the battery cell exceeds a preset value.

22. The battery cell according to claim 21, wherein: The sealing gasket also includes a fourth part, which is connected to the third part and extends along the radial direction of the battery shell toward the central axis of the battery shell, and the current interruption element is arranged on the fourth part.

23. The battery cell according to claim 22, wherein: The battery cell further includes a CID gasket disposed on the fourth portion, wherein the CID gasket wraps around an outer peripheral edge of the current interruption element to block contact between the current interruption element and the safety vent.

24. A battery pack, characterized in that: Comprising at least one battery cell according to any one of claims 1 to 23.

25. A car, characterized in that: It comprises at least one battery pack as claimed in claim 24.

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