Cap assembly, battery cell, battery, power-consuming device, method and equipment

Abstract

The embodiment of the present application provides a cover assembly, a battery cell, a battery, an electrical device, a method and an apparatus, wherein the cover assembly includes a cover plate, a fixing member, a breathable membrane and a support member, wherein the cover plate has a first through hole; the fixing member is used to connect the cover plate, the fixing member has a second through hole, and the second through hole is configured to be gas-connected with the first through hole; the breathable membrane is connected to the fixing member, and the breathable membrane is used to cover the second through hole; the support member is filled in the second through hole and connected to the fixing member, and the support member is used to support the breathable membrane and allow the gas passing through the breathable membrane to pass. The present application can meet the requirements for releasing the internal gas of the battery cell, and at the same time can ensure the safety performance of the battery cell.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and in particular to a cover assembly, a battery cell, a battery, an electrical device, a method and an apparatus. Background Art

[0002] Rechargeable battery cells have been widely used in electric vehicles due to their high energy density, high power density, many cycles, and long storage time. At present, the exhaust safety of battery cells restricts the development of battery cells, so the research on the relevant technologies of battery cell safety performance has become one of the research topics. Summary of the invention

[0003] The embodiments of the present application provide a cover assembly, a battery cell, a battery, an electrical device, a method and an apparatus. The cover assembly can meet the requirements for releasing the internal gas of the battery cell while ensuring the safety performance of the battery cell.

[0004] On the one hand, according to an embodiment of the present application, a cover assembly of a battery cell is proposed, including: a cover plate, a fixing member, a breathable membrane and a support member, the cover plate having a first through hole; the fixing member is used to connect the cover plate, the fixing member has a second through hole, and the second through hole is configured to be gas-connected to the first through hole; the breathable membrane is connected to the fixing member, and the breathable membrane is used to cover the second through hole; the support member fills the second through hole and is connected to the fixing member, and the support member is used to support the breathable membrane and allow gas to pass through the breathable membrane.

[0005] According to the cover assembly provided in the embodiment of the present application, it includes a cover plate, a fixing member, a breathable membrane and a support member. The second through hole is gas-connected with the first through hole, and the breathable membrane has a breathable function. Therefore, the gas generated by the battery cell can be discharged to the outside of the battery cell through the breathable membrane, avoiding gas accumulation inside the shell, improving the performance of the electrode assembly, and increasing the life of the battery cell. The setting of the support member can provide support for the breathable membrane, ensuring that the breathable membrane still maintains its integrity when the internal pressure of the battery cell is high, avoiding the occurrence of breathable membrane damage, ensuring the breathable performance of the breathable membrane during the life of the battery cell, and thus ensuring the safety performance of the battery cell.

[0006] According to one aspect of the embodiment of the present application, the melting point of the support member is greater than the melting point of the breathable membrane. When the temperature of the battery cell reaches the melting point of the breathable membrane, the breathable membrane deforms and flows. Since the melting point of the support member is greater than the melting point of the breathable membrane, the material of the support member has not reached its melting point at this time, and can play a supporting skeleton role for the breathable membrane material, reducing the flow and deformation of the breathable membrane.

[0007] According to one aspect of the embodiment of the present application, the difference between the melting point of the support member and the melting point of the breathable membrane is greater than or equal to 10° C. This can effectively prevent the support member from deforming when the breathable membrane deforms and flows, thereby ensuring the support for the breathable membrane material.

[0008] According to one aspect of the embodiment of the present application, the shear strength of the connection between the support member and the fixing member is greater than or equal to 0.3 MPa. When the internal pressure of the battery cell increases, the shape stability of the support member and the stability of the connection strength between the support member and the fixing member can be ensured, the support effect of the breathable membrane is ensured, the deformation or even rupture of the breathable membrane is avoided, and the ventilation effect of the breathable membrane is ensured.

[0009] According to one aspect of the embodiment of the present application, the air permeability of the support is greater than that of the breathable membrane. Since the breathable membrane is the material that controls the entire breathability of the battery, the gas that passes through the breathable membrane needs to be able to be smoothly discharged from the support to the outside of the battery cell. By making the air permeability of the support greater than that of the breathable membrane, the gas inside the battery cell through the breathable membrane can be smoothly discharged from the support, thereby ensuring the safety performance of the battery cell.

[0010] According to one aspect of the embodiment of the present application, the fixing member is a metal ring having a second through hole, the supporting member includes a hydrophobic breathable material, and the supporting member and the fixing member are connected by a chemical bond or a metal bond. Through the above arrangement, on the basis of meeting the requirements for the breathable membrane support, it can also ensure that the gas passing through the breathable membrane can pass smoothly through the supporting member, ensuring the breathable effect of the breathable membrane, and can also block water vapor, etc., to prevent water vapor from entering the battery cell and affecting the battery cell, and can also prevent the electrolyte inside the battery cell from being exposed, and can also ensure the connection strength between the supporting member and the fixing member.

[0011] According to one aspect of the embodiment of the present application, in the radial direction of the first through hole, the difference between the maximum size of the breathable membrane and the maximum size of the support is greater than or equal to 8 mm, and in the axial direction of the first through hole, the orthographic projection of the geometric center of the breathable membrane coincides with the orthographic projection of the geometric center of the support. This ensures the bonding area between the periphery of the breathable membrane and the support, and ensures the composite strength and sealing performance between the breathable membrane and the support.

[0012] According to one aspect of the embodiment of the present application, the aperture of the second through hole remains unchanged along the direction away from the breathable membrane.

[0013] According to one aspect of the embodiment of the present application, the aperture of at least part of the length of the second through hole tends to decrease along the direction away from the breathable membrane. When the cover assembly is used in a battery cell, one side of the breathable membrane faces the battery assembly and directly contacts the gas inside the battery cell. By making the aperture of at least part of the length of the second through hole tend to decrease along the direction away from the breathable membrane, when the breathable membrane is deformed outward under the action of the internal air pressure of the battery cell, the hole wall enclosing the second through hole will provide certain support to the breathable membrane at the position where the aperture is reduced, avoiding its deformation and ensuring the breathability effect and safety performance of the breathable membrane.

[0014] According to one aspect of the embodiment of the present application, the aperture of the second through hole gradually decreases in a direction away from the breathable membrane.

[0015] According to one aspect of the embodiment of the present application, the aperture of the second through hole decreases step by step along a direction away from the breathable membrane.

[0016] According to one aspect of the embodiment of the present application, along the direction away from the breathable membrane, the aperture of the second through hole first decreases and then increases.

[0017] According to one aspect of the embodiment of the present application, the first through hole includes a receiving section and an extending section extending from the receiving section, the aperture of the receiving section is larger than the aperture of the extending section, and the fixing member and the supporting member are at least partially received in the receiving section, so as to reduce the space occupied by the fixing member and reduce the overall height of the battery cell.

[0018] According to one aspect of the embodiment of the present application, the accommodating section has a bottom wall surrounding the extension section, the breathable membrane is at least partially clamped between the fixing member and the bottom wall to separate the second through hole and the extension section, and the support member is arranged on the side of the breathable membrane away from the extension section. The accommodating section and the extension section with different apertures form a step surface (i.e., the bottom wall), and the step surface can support the fixing member, which is convenient for positioning the fixing member when welding the fixing member and the cover plate.

[0019] According to one aspect of the embodiment of the present application, the fixing member has a groove, which is arranged around the second through hole, and the breathable membrane is at least partially accommodated in the groove. By providing the groove, the space occupied by the breathable membrane can be reduced, and the overall thickness of the fixing member and the breathable membrane can be reduced.

[0020] On the other hand, according to an embodiment of the present application, a battery cell is provided, comprising: a shell having an opening; an electrode assembly accommodated in the shell; and the above-mentioned cover assembly, the cover assembly is connected to the shell and covers the opening of the shell, and the breathable membrane is located between the electrode assembly and the support member.

[0021] The battery cell provided in the embodiment of the present application includes the cap assembly provided in the above embodiments, and the gas generated inside the battery cell can be discharged to the outside of the battery cell through the breathable membrane, thereby avoiding gas accumulation inside the shell, improving the performance of the electrode assembly, and having a longer service life. In addition, the setting of the support member in the cap assembly can provide support for the breathable membrane, ensuring that the breathable membrane maintains its integrity when the internal pressure of the battery cell is high, avoiding the occurrence of breathable membrane damage, and ensuring the breathability of the breathable membrane during the life of the battery cell, thereby making the battery cell have better safety performance.

[0022] On the other hand, according to an embodiment of the present application, a battery is provided, comprising the above-mentioned battery cell.

[0023] On the other hand, according to an embodiment of the present application, there is provided an electrical device, comprising the above-mentioned battery, wherein the battery is used to provide electrical energy.

[0024] On the other hand, according to an embodiment of the present application, there is provided a method for preparing a battery cell, comprising:

[0025] providing a housing having an opening;

[0026] Providing an electrode assembly, and installing the electrode assembly into a housing;

[0027] A cover assembly is provided, which includes a cover plate, a fixing member, a breathable membrane and a supporting member, wherein the cover plate has a first through hole, the fixing member is used to connect the cover plate, the fixing member has a second through hole, the second through hole is configured to be gas-connected with the first through hole, the breathable membrane is connected to the fixing member, the breathable membrane is used to cover the second through hole, the supporting member fills the second through hole and is connected to the fixing member, and the supporting member is used to support the breathable membrane; the cover assembly is set at the opening and connected to the shell through the cover plate, and the gas in the shell passes through the breathable membrane and the fixing member.

[0028] On the other hand, according to an embodiment of the present application, there is provided an apparatus for preparing a battery cell, comprising:

[0029] A first assembly device is configured to provide a housing having an opening;

[0030] A second assembly device is configured to provide an electrode assembly and install the electrode assembly into the housing;

[0031] The third assembly device is configured to provide a cover assembly, which includes a cover plate, a fixing member, a breathable membrane and a support member, the cover plate has a first through hole, the fixing member is used to connect the cover plate, the fixing member has a second through hole, the second through hole is configured to be gas-connected with the first through hole, the breathable membrane is connected to the fixing member, the breathable membrane is used to cover the second through hole, the support member is filled in the second through hole and connected to the fixing member, the support member is used to support the breathable membrane, the cover assembly is set at the opening and connected to the shell through the cover plate, and the gas in the shell passes through the breathable membrane and the fixing member. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments of the present application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the drawings without paying creative work.

[0033] Figure 1 is a structural schematic diagram of a vehicle according to an embodiment of the present application;

[0034] Figure 2 is a schematic diagram of the exploded structure of a battery pack according to an embodiment of the present application;

[0035] Figure 3 is a partial structural schematic diagram of a battery module according to an embodiment of the present application;

[0036] Figure 4 is a schematic structural diagram of a battery cell according to an embodiment of the present application;

[0037] Figure 5 is a side view of a battery cell according to an embodiment of the present application;

[0038] Figure 6 yes Figure 5 The cross-sectional view along the AA direction;

[0039] Figure 7 yes Figure 6 A partial enlarged view of point B in the middle;

[0040] Figure 8 is a schematic diagram of a partial exploded structure of a cover assembly according to an embodiment of the present application;

[0041] Fig. 9 It is a partial structural schematic diagram of a cover plate of an embodiment of the present application;

[0042] Fig.10 is a partial structural schematic diagram of a cover assembly of another embodiment of the present application;

[0043] Fig.11 is a partial structural schematic diagram of a cover assembly of another embodiment of the present application;

[0044] Fig.12 is a partial structural schematic diagram of a cover assembly of yet another embodiment of the present application;

[0045] Fig.13 is a partial structural schematic diagram of a cover assembly of yet another embodiment of the present application;

[0046] Fig.14 is a schematic flow chart of a method for preparing a battery cell according to an embodiment of the present application;

[0047] Fig.15 It is a schematic diagram of the structure of an apparatus for preparing a battery cell according to an embodiment of the present application.

[0048] In the drawings, the drawings are not drawn to scale.

[0049] Marking Description:

[0050] 1-vehicle; 1a-motor; 1b-controller; 10-battery; 11-first shell; 12-second shell; 20-battery module; 30-battery cell; 31-shell; 32-electrode assembly; 33-cover assembly; 331-cover plate; 332-fixing member; 333-breathable membrane; 334-support member; 335-electrode terminal; 336-explosion-proof plate; 337-first through hole; 337a-accommodating section; 337b-extension section; 337c-bottom wall; 338-second through hole; 339-groove; 100-equipment; 101-first assembly device; 102-second assembly device; 103-third assembly device. DETAILED DESCRIPTION

[0051] The following detailed description and drawings of the embodiments of the present application are used to illustrate the principles of the present application, but cannot be used to limit the scope of the present application, that is, the present application is not limited to the described embodiments.

[0052] In the description of the present application, it should be noted that, unless otherwise specified, "multiple" means more than two; the terms "upper", "lower", "left", "right", "inside", "outside", etc., indicating the orientation or positional relationship, are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first", "second", "third", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance. "Vertical" is not strictly vertical, but is within the allowable error range. "Parallel" is not strictly parallel, but is within the allowable error range.

[0053] The directional words appearing in the following description are all directions shown in the figures, and do not limit the specific structure of this application. In the description of this application, it should also be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected or indirectly connected through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to the specific circumstances.

[0054] After the applicant discovered that the cover assembly with a breathable membrane was prone to rupture of the breathable membrane during operation, the applicant conducted research and analysis on the cover assembly. The applicant discovered that because the breathable membrane used in the cover assembly is very thin, it has problems such as low strength and easy deformation, which causes the number of nanopores or micropores inside the breathable membrane to increase and the pore size to increase when the breathable membrane is stretched and plastically deformed, which in turn leads to a larger air permeability. While the amount of gas permeation from the inside of the battery cell increases, it is also accompanied by excessive water vapor from the outside penetrating into the battery cell, posing risks to the electrical properties (such as life, DCR, etc.) and safety performance of the battery cell. In addition, when the internal pressure of the battery cell increases, the breathable membrane is at risk of rupture, which will lead to a series of failures caused by leakage of the battery cell.

[0055] Based on the above problems found by the applicant, the applicant has improved the structure of the battery cell. The embodiments of the present application are further described below.

[0056] In order to better understand this application, Figures 1 to 15 The embodiments of the present application are described.

[0057] See also Figure 1 As shown, an embodiment of the present application provides an electrical device using a battery 10 as a power source. The electrical device can be, but is not limited to, a vehicle, a ship, or an aircraft, etc. An embodiment of the present application provides a vehicle 1. Vehicle 1 can be a fuel vehicle, a gas vehicle, or a new energy vehicle. A new energy vehicle can be a pure electric vehicle, a hybrid vehicle, or an extended-range vehicle, etc. In an embodiment of the present application, vehicle 1 may include a motor 1a, a controller 1b, and a battery 10. Controller 1b is used to control battery 10 to power motor 1a. Motor 1a is connected to the wheel through a transmission mechanism to drive vehicle 1 to move. Battery 10 can be used as a driving power source for vehicle 1, replacing or partially replacing fuel or natural gas to provide driving power for vehicle 1. In one example, battery 10 can be set at the bottom, front, or rear of vehicle 1. Battery 10 can be used to power vehicle 1. In one example, battery 10 can be used as an operating power source for vehicle 1, for the circuit system of vehicle 1. Exemplarily, battery 10 can be used for the working power demand of vehicle 1 during startup, navigation, and operation.

[0058] See also Figure 2 As shown, the battery 10 may include more than two battery modules 20. In some optional embodiments, the battery 10 also includes a case. The battery module 20 is arranged in the case. Two or more battery modules 20 are arranged in the case. The type of the case is not limited. The case may be a frame-shaped case, a disc-shaped case or a box-shaped case, etc. Exemplarily, the case includes a first shell 11 for accommodating the battery module 20 and a second shell 12 covering the first shell 11. The first shell 11 and the second shell 12 are covered to form a accommodating portion for accommodating the battery module 20. In some embodiments, the battery 10 may also include one battery module 20. In other optional embodiments, the battery 10 includes a case 11 and a plurality of battery cells directly arranged in the case.

[0059] See also Figure 3 As shown, in order to meet different power usage requirements, the battery module 20 may include one or more battery cells 30. A plurality of battery cells 30 may be first connected in series, in parallel or in a mixed connection to form a battery module 20, and a plurality of battery modules 20 may then be connected in series, in parallel or in a mixed connection to form a battery. Mixed connection refers to a mixture of series connection and parallel connection. Exemplarily, the battery 10 may include a plurality of battery cells 30, wherein a plurality of battery cells 30 may be connected in series, in parallel or in a mixed connection. A plurality of battery cells 30 may be directly disposed in the housing. In other words, a plurality of battery cells 30 may directly form a battery 10, or may first form a battery module 20, and the battery module 20 may then form a battery 10. The battery cells 30 include lithium-ion battery cells, lithium-ion primary batteries, lithium-sulfur batteries, sodium-lithium-ion batteries or magnesium-ion batteries, but are not limited thereto.

[0060] When the battery cell 30 of the embodiment of the present application is applied to the vehicle 1, the width of the battery cell 30 is the same as the height of the vehicle 1. Due to the space limitation in the height direction of the vehicle 1, the width of the battery cell 30 is also strictly limited, so when the capacity of the battery cell 30 needs to be increased, the width of the battery cell 30 cannot be increased infinitely, but the length of the battery cell 30 can be increased.

[0061] See also Figures 4 to 6 As shown, the battery cell of the embodiment of the present application includes a shell 31 and an electrode assembly 32 disposed in the shell 31. The shell 31 of the embodiment of the present application is a square structure or other shapes. The shell 31 has an internal space for accommodating the electrode assembly 32 and the electrolyte and an opening connected to the internal space. The shell 31 can be made of materials such as aluminum, aluminum alloy or plastic. The electrode assembly 32 is the core component of the battery cell 30 to realize the charging and discharging functions.

[0062] The electrode assembly of the embodiment of the present application can be formed by stacking or winding the first electrode sheet, the second electrode sheet, and the separator between the first electrode sheet and the second electrode sheet, wherein the separator is an insulator between the first electrode sheet and the second electrode sheet. In this embodiment, the first electrode sheet is a positive electrode sheet and the second electrode sheet is a negative electrode sheet. Both the positive electrode sheet and the negative electrode sheet include a coating area and an uncoated area, and the positive electrode sheet active material is coated on the coating area of ​​the positive electrode sheet, while the negative electrode sheet active material is coated on the coating area of ​​the negative electrode sheet. On the coating area, the active material is coated on the current collector formed by the thin metal foil, and no active material is coated on the uncoated area. The electrode assembly 32 also includes two pole ears, namely the positive pole ear and the negative pole ear. The coating area of ​​the positive electrode sheet and the coating area of ​​the negative electrode sheet form the main body. The uncoated area of ​​the positive electrode sheet is stacked to form the positive pole ear, and the uncoated area of ​​the negative electrode sheet is stacked to form the negative pole ear. In some embodiments, the main body has two end surfaces that are oppositely disposed along a height direction, and the positive electrode tab and the negative electrode tab may extend from one end surface of the main body, respectively.

[0063] The battery cell 30 of the embodiment of the present application further includes a cap assembly 33. The cap assembly 33 is connected to the housing 31 and closes the opening of the housing 31. Exemplarily, the cap assembly 33 and the housing 31 may be connected by welding.

[0064] See also Figures 4 to 9 As shown, the cover assembly 33 provided in the embodiment of the present application includes a cover plate 331, a fixing member 332, a breathable membrane 333 and a supporting member 334, and the cover plate 331 has a first through hole 337. The fixing member 332 is used to connect the cover plate 331, and the fixing member 332 has a second through hole 338, and the second through hole 338 is configured to be gas-connected with the first through hole 337. The breathable membrane 333 is connected to the fixing member 332, and the breathable membrane 333 is used to cover the second through hole 338. The supporting member 334 is filled in the second through hole 338 and connected to the fixing member 332, and the supporting member 334 is used to support the breathable membrane 333 and allow the gas passing through the breathable membrane 333 to pass.

[0065] Since the electrode assembly 32 generates gas (such as CO, CO2, CH4, C2H6, H2 and other gases) during the charge and discharge process, as the gas accumulates, the internal pressure inside the housing 31 increases continuously, which easily causes the risk of battery deformation and deterioration of the performance of the electrode assembly 32. In the battery cell 30 according to the first exemplary embodiment, the second through hole 338 is in gas communication with the first through hole 337, and the air-permeable membrane 333 has a gas-permeable function, so the generated gas can be discharged to the outside of the battery cell 30 through the first through hole 337, the air-permeable membrane 333 and the second through hole 338, thereby avoiding gas accumulation inside the housing 31, improving the performance of the electrode assembly 32, and increasing the life of the battery cell 30.

[0066] The setting of the support member 334 can provide support for the breathable membrane 333, ensuring that the breathable membrane 333 maintains its integrity when the internal pressure of the battery cell 30 is relatively high, avoiding the occurrence of damage to the breathable membrane 333, and ensuring the breathability of the breathable membrane 333 during the entire life of the battery cell 30, thereby ensuring the safety performance of the battery cell 30.

[0067] Optionally, the cap assembly 33 further includes an electrode terminal 335, which is disposed on the cap plate 331, extends outside the cap plate 331 and is electrically connected to the positive electrode sheet and the negative electrode sheet, respectively, and the shape of the electrode terminal 335 can be circular or square, which is not limited here. Two or more battery cells 30 can be connected in series, in parallel, or in mixed connection through their respective electrode terminals 335.

[0068] Optionally, the cover plate 331 is formed as a metal thin plate, which is provided with an injection hole for injecting an electrolyte solution and a sealing plug for sealing the injection hole. The cover plate 331 is also provided with a through terminal hole, and the electrode terminal 335 is provided on one side of the cover plate 331 and covers the terminal hole. The electrode terminal 335 is formed in a cylindrical shape and is fixed to the cover plate 331 by a connector surrounding its outer circumference.

[0069] Optionally, the cover assembly 33 further includes a burst disk 336 , which is configured to rupture when the internal pressure of the housing 31 reaches a set value.

[0070] Optionally, the cover plate 331 is provided with a through exhaust hole, and the explosion-proof sheet 336 is fixed to the cover plate 331 and covers the exhaust hole. The explosion-proof sheet 336 has a weak area. When the electrode assembly 32 generates a large amount of gas due to overcharging, short circuit, etc., the gas pressure inside the battery cell 30 increases and breaks through the explosion-proof sheet 336 at the weak area, and the gas is discharged to the outside of the battery cell 30 through the exhaust hole, thereby reducing the risk of explosion of the battery cell 30.

[0071] See also Figures 7 to 9 As shown, optionally, in the cover assembly 33 provided in the above embodiments of the present application, the first through hole 337 of the cover plate 331 connects the spaces on both sides of the cover plate 331. In one embodiment, the first through hole 337 passes through the cover plate 331 along the thickness direction of the cover plate 331, that is, the axis of the first through hole 337 is parallel to the thickness direction of the cover plate 331.

[0072] In some embodiments, the fixing member 332 is connected to the cover plate 331. Optionally, the fixing member 332 is fixedly connected to the cover plate 331 by welding.

[0073] Optionally, the second through hole 338 of the fixing member 332 passes through the fixing member 332 along the thickness direction of the cover plate 331, that is, the axis of the second through hole 338 may also be parallel to the thickness direction of the cover plate 331. The gas in the first through hole 337 can flow freely into the second through hole 338, and of course, the gas in the second through hole 338 can also flow freely into the first through hole 337.

[0074] In some optional embodiments, the fixing member 332 is a metal ring having a second through hole 338 , which has a simple structure and is convenient for connection with the cover plate 331 and installation of the breathable membrane 333 .

[0075] In some optional embodiments, the breathable membrane 333 is made of a polymer material with breathable properties (such as one or a combination of two or more of PP, PE and PU) and can block liquid. The breathable membrane 333 and the fixing member 332 are connected as a whole and block the first through hole 337. Therefore, the breathable membrane 333 and the fixing member 332 can block the electrolyte solution and prevent leakage of the electrolyte solution.

[0076] Optionally, the breathable membrane 333 and the fixing member 332 are connected by a chemical bond (ionic bond or covalent bond). Specifically, the breathable membrane 333 and the fixing member 332 are first surface treated to form functional groups on the surface of the breathable membrane 333 and the surface of the fixing member 332, and then the breathable membrane 333 and the fixing member 332 are connected by thermal bonding, and at the bonding surface of the breathable membrane 333 and the fixing member 332, the functional groups of the breathable membrane 333 and the functional groups of the fixing member 332 are connected by chemical bonds.

[0077] The breathable membrane 333 is directly connected to the fixing member 332 through a chemical bond, which can effectively increase the connection strength between the breathable membrane 333 and the fixing member 332 , reduce the risk of the breathable membrane 333 detaching from the fixing member 332 under gas impact, and improve the sealing performance of the battery cell 30 .

[0078] Optionally, at least a portion of the breathable membrane 333 is clamped between the fixing member 332 and the cover plate 331. The fixing member 332 and the cover plate 331 can clamp the breathable membrane 333, thereby further reducing the risk of the breathable membrane 333 falling off.

[0079] Alternatively, see Fig. 9 As shown, the first through hole 337 includes a receiving section 337a and an extension section 337b extending from the receiving section 337a, and the aperture of the receiving section 337a is larger than the aperture of the extension section 337b. The receiving section 337a and the extension section 337b are coaxial holes. The extension section 337b is located on a side of the receiving section 337a close to the electrode assembly 32. The fixing member 332 is at least partially accommodated in the receiving section 337a to reduce the space occupied by the fixing member 332 and reduce the overall height of the battery cell 30.

[0080] The accommodating section 337a has a bottom wall 337c surrounding the extension section 337b, and the fixing member 332 is located on one side of the bottom wall 337c. The accommodating section 337a and the extension section 337b with different apertures form a stepped surface (i.e., the bottom wall 337c), which can support the fixing member 332 and facilitate the positioning of the fixing member 332 when welding the fixing member 332 and the cover plate 331. The accommodating section 337a also has a side wall surrounding the fixing member 332, and the bottom wall 337c and the side wall enclose the accommodating section 337a.

[0081] At least a portion of the breathable membrane 333 is clamped between the fixing member 332 and the bottom wall 337c to separate the second through hole 338 and the extension section 337b, and the support member 334 is disposed on the side of the breathable membrane 333 away from the extension section 337b. The breathable membrane 333 is entirely located outside the extension section 337b, and the annular edge portion of its periphery is clamped between the fixing member 332 and the bottom wall 337c. In order to improve the sealing performance and prevent the electrolyte solution from flowing out from between the bottom wall 337c and the breathable membrane 333, the edge portion is in a compressed state.

[0082] Optionally, the fixing member 332 has a groove 339, which is arranged around the second through hole 338, and the breathable membrane 333 is at least partially accommodated in the groove 339. By providing the groove 339, the space occupied by the breathable membrane 333 can be reduced, and the overall thickness of the fixing member 332 and the breathable membrane 333 can be reduced. The thickness of the breathable membrane 333 can be slightly greater than the depth of the groove 339. When the fixing member 332 and the cover plate 331 are assembled, the fixing member 332 is attached to the bottom wall 337c, and the breathable membrane 333 is compressed, thereby improving the sealing performance.

[0083] Optionally, the fixing member 332 is welded to the cover plate 331. Specifically, the welding is performed along the junction between the side wall and the outer edge of the fixing member 332.

[0084] As an optional implementation, the cover assembly 33 provided in the embodiment of the present application, the support member 334 includes a hydrophobic breathable material. The support member 334 adopts the hydrophobic breathable material. On the basis of meeting the support requirements for the breathable membrane 333, it can also ensure that the gas passing through the breathable membrane 333 can pass smoothly through the support member 334, thereby ensuring the breathability of the breathable membrane 333, and can also block water vapor, etc., to prevent water vapor from entering the battery cell 30 and affecting the battery cell 30, and can also prevent the electrolyte inside the battery cell 30 from being exposed.

[0085] Optionally, the support member 334 is filled in the second through hole 338 and connected to the fixing member 332 by a chemical bond (ionic bond or covalent bond). For example, the support member 334 and the fixing member 332 can be surface treated first to form functional groups on the surface of the support member 334 and the surface of the fixing member 332, and then the support member 334 and the fixing member 332 are connected by thermal bonding. At the bonding surface of the support member 334 and the fixing member 332, the functional groups of the support member 334 and the functional groups of the fixing member 332 are connected by chemical bonds. Of course, in some embodiments, the support member 334 and the fixing member 332 can also be connected by a metal bond, mechanical fit or adhesive fit, etc., as long as the connection strength requirements between the support member 334 and the fixing member 332 can be met.

[0086] like Fig.10 As shown, as an optional implementation, the aperture of the second through hole 338 can remain unchanged along the direction away from the breathable membrane 333, which facilitates the molding of the second through hole 338 and the setting of the support member 334, thereby ensuring the support requirement for the breathable membrane 333.

[0087] See also Figures 11 to 13 As shown, in some embodiments, the aperture of at least a portion of the second through hole 338 along the direction away from the breathable membrane 333 is decreasing. When the cap assembly 33 is used in the battery cell 30, one side of the breathable membrane 333 faces the battery assembly and directly contacts the gas inside the battery cell 30. By making the aperture of at least a portion of the second through hole 338 along the direction away from the breathable membrane 333 decrease, when the breathable membrane 333 is deformed outwards under the action of the internal air pressure of the battery cell 30, the hole wall enclosing the second through hole 338 at the position where the aperture is reduced will provide certain support to the breathable membrane 333, reduce or avoid its deformation, and ensure the breathability effect and safety performance of the breathable membrane 333.

[0088] For example, see Fig.11 As shown, the diameter of the second through hole 338 may gradually decrease in a direction away from the breathable membrane 333 . The second through hole 338 may be in the form of a tapered hole. The support member 334 fills the second through hole 338 and is connected to the fixing member 332 .

[0089] In some examples, such as Fig.12 As shown, the diameter of the second through hole 338 decreases step by step in a direction away from the breathable membrane 333 . The second through hole 338 may be in the form of a stepped hole. The support member 334 fills the second through hole 338 and is connected to the fixing member 332 .

[0090] Of course, in some other examples, such as Fig.13As shown, the aperture of the second through hole 338 can first decrease and then increase in the direction away from the breathable membrane 333 , which can also meet the breathability effect and safety performance requirements of the breathable membrane 333 .

[0091] In some optional embodiments, the melting point of the support member 334 is greater than the melting point of the breathable membrane 333. When the temperature of the battery cell 30 reaches the melting point of the breathable membrane 333, the breathable membrane 333 deforms and flows. Since the melting point of the support member 334 is greater than the melting point of the breathable membrane 333, the material of the support member 334 has not reached its melting point at this time, and can play a supporting skeleton role for the material of the breathable membrane 333, thereby reducing the flow and deformation of the breathable membrane 333.

[0092] As an optional implementation, in the cover assembly 33 provided in the embodiment of the present application, the difference between the melting point of the support member 334 and the melting point of the breathable membrane 333 is greater than or equal to 10° C. Through the above arrangement, the support member 334 can be effectively prevented from deforming when the breathable membrane 333 deforms and flows, thereby ensuring the support for the breathable membrane 333.

[0093] In some optional embodiments, the shear strength of the connection between the support member 334 and the fixing member 332 is greater than or equal to 0.3 MPa. Through the above arrangement, when the internal pressure of the battery cell 30 increases, the shape stability of the support member 334 and the stability of the connection strength between the support member 334 and the fixing member 332 can be ensured, the support effect of the breathable membrane 333 is ensured, the deformation or even rupture of the breathable membrane 333 is avoided, and the ventilation effect of the breathable membrane 333 is ensured.

[0094] As an optional implementation, the cap assembly 33 provided in the embodiment of the present application has a support member 334 with a greater air permeability than the air permeability of the air permeable membrane 333. Since the air permeable membrane 333 is a material that controls the entire air permeability of the battery, the gas that passes through the air permeable membrane 333 needs to be able to be smoothly discharged from the support member 334 to the outside of the battery cell 30. By making the air permeability of the support member 334 greater than the air permeability of the air permeable membrane 333, the gas inside the battery cell 30 through the air permeable membrane 333 can be smoothly discharged from the support member 334, thereby ensuring the safety performance of the battery cell 30.

[0095] In some optional embodiments, in the radial direction of the first through hole 337, the difference between the maximum size of the breathable membrane 333 and the maximum size of the support member 334 is greater than or equal to 8 mm, and in the axial direction of the first through hole 337, the orthographic projection of the geometric center of the breathable membrane 333 coincides with the orthographic projection of the geometric center of the support member 334. Through the above arrangement, the bonding area between the periphery of the breathable membrane 333 and the support member 334 can be ensured, and the composite strength and sealing performance between the breathable membrane 333 and the support member 334 can be ensured.

[0096] like Fig.14As shown, on the other hand, the present application embodiment also provides a method for preparing a battery cell 30, which can be used to prepare Figures 4 to 13 The battery cell of the embodiment shown, the method includes:

[0097] S100 , providing a housing 31 , wherein the housing 31 has an opening.

[0098] S200 , providing an electrode assembly 32 , and installing the electrode assembly 32 into a shell 31 .

[0099] S300, provide a cover assembly 33, the cover assembly 33 includes a cover plate 331, a fixing member 332, a breathable membrane 333 and a support member 334, the cover plate 331 has a first through hole 337, the fixing member 332 is used to connect the cover plate 331, the fixing member 332 has a second through hole 338, the second through hole 338 is configured to be gas-connected with the first through hole 337, the breathable membrane 333 is connected to the fixing member 332, the breathable membrane 333 is used to cover the second through hole 338, the support member 334 is filled in the second through hole 338 and connected to the fixing member 332, and the support member 334 is used to support the breathable membrane 333. The cover assembly 33 is set at the opening of the housing 31 and connected to the housing 31 through the cover plate 331, and the gas in the housing 31 passes through the breathable membrane 333 and the fixing member 332.

[0100] The gas generated inside the battery cell 30 prepared by the method for preparing the battery cell 30 provided in the embodiment of the present application can be discharged to the outside of the battery cell 30 through the breathable membrane 333, so as to avoid gas accumulation inside the shell 31, improve the performance of the electrode assembly 32, and increase the life of the battery cell 30. The setting of the support member 334 can provide support for the breathable membrane 333, ensure that the breathable membrane 333 maintains its integrity when the internal pressure of the battery cell 30 is relatively large, avoid the occurrence of damage to the breathable membrane 333, ensure the breathable performance of the breathable membrane 333 during the life of the battery cell 30, and thus ensure the safety performance of the battery cell 30.

[0101] like Fig.15 As shown, on the other hand, the embodiment of the present application also provides an apparatus 100 for preparing a battery cell 30, which can be used for preparing Figures 4 to 13The battery cell of the embodiment shown, the device 100 includes a first assembly device 101, a second assembly device 102 and a third assembly device 103. The first assembly device 101 is configured to provide a housing 31 having an opening. The second assembly device 102 is configured to provide an electrode assembly 32 and to install the electrode assembly 32 into the housing 31. The third assembly device 103 is configured to provide a cover assembly 33, which includes a cover plate 331, a fixing member 332, a breathable membrane 333 and a support member 334. The cover plate 331 has a first through hole 337, the fixing member 332 is used to connect the cover plate 331, the fixing member 332 has a second through hole 338, and the second through hole 338 is configured to be gas-connected with the first through hole 337. The breathable membrane 333 is connected to the fixing member 332, and the breathable membrane 333 is used to cover the second through hole 338. The support member 334 fills the second through hole 338 and is connected to the fixing member 332, and the support member 334 is used to support the breathable membrane 333. The cover assembly 33 is set at the opening and connected to the shell 31 through the cover plate 331. The gas in the shell 31 passes through the breathable membrane 333 and the fixing member 332.

[0102] The equipment for preparing the battery cell 30 provided in the embodiment of the present application can be used to prepare the battery cell 30 provided in the above-mentioned embodiments, and the gas generated inside the prepared battery cell 30 can be discharged to the outside of the battery cell 30 through the breathable membrane 333, so as to avoid gas accumulation inside the shell 31, improve the performance of the electrode assembly 32, and increase the life of the battery cell 30. The setting of the support member 334 can provide support for the breathable membrane 333, ensure that the breathable membrane 333 maintains its integrity when the internal pressure of the battery cell 30 is relatively large, avoid the occurrence of damage to the breathable membrane 333, ensure the breathable performance of the breathable membrane 333 during the life of the battery cell 30, and thus ensure the safety performance of the battery cell 30.

[0103] Although the present application has been described with reference to preferred embodiments, various modifications may be made thereto and parts thereof may be replaced with equivalents without departing from the scope of the present application. In particular, the various technical features mentioned in the various embodiments may be combined in any manner as long as there are no structural conflicts. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A battery cell cover assembly, wherein: include: A cover plate, wherein the cover plate has a first through hole; A fixing member, the fixing member is used to connect the cover plate, the fixing member has a second through hole, and the second through hole is configured to be in gas communication with the first through hole; a breathable membrane, the breathable membrane being connected to the fixing member and being used for covering the second through hole; a support member, the support member being filled in the second through hole and connected to the fixing member, the support member being used to support the breathable membrane and allow the gas passing through the breathable membrane to pass through; The fixing member is a metal ring having the second through hole, the supporting member comprises a hydrophobic and breathable material, and the supporting member is connected to the fixing member via a chemical bond or a metal bond.

2. The cap assembly according to claim 1, wherein: The melting point of the support member is greater than the melting point of the breathable membrane.

3. The cap assembly according to claim 2, wherein: The difference between the melting point of the support member and the melting point of the breathable membrane is greater than or equal to 10°C.

4. The cap assembly according to any one of claims 1 to 3, wherein: The shear strength of the connection between the support member and the fixing member is greater than or equal to 0.3 MPa.

5. The cap assembly according to any one of claims 1 to 3, wherein: The air permeability of the support member is greater than the air permeability of the air permeability membrane.

6. The cap assembly according to any one of claims 1 to 3, wherein: In the radial direction of the first through hole, the difference between the maximum size of the breathable membrane and the maximum size of the support member is greater than or equal to 8 mm, and in the axial direction of the first through hole, the orthographic projection of the geometric center of the breathable membrane coincides with the orthographic projection of the geometric center of the support member.

7. The cap assembly according to any one of claims 1 to 3, wherein: Along the direction away from the breathable membrane, the aperture of the second through hole remains unchanged.

8. The cap assembly according to any one of claims 1 to 3, wherein: Along the direction away from the breathable membrane, the aperture of at least a portion of the length of the second through hole tends to decrease.

9. The cap assembly according to claim 8, wherein: The aperture of the second through hole gradually decreases in a direction away from the breathable membrane; Alternatively, the aperture of the second through hole decreases step by step in a direction away from the breathable membrane; Alternatively, along the direction away from the breathable membrane, the diameter of the second through hole first decreases and then increases.

10. The cap assembly according to any one of claims 1 to 3, wherein: The first through hole includes a receiving section and an extending section extending from the receiving section. The aperture of the receiving section is larger than the aperture of the extending section. The fixing member and the supporting member are at least partially received in the receiving section.

11. The cap assembly according to claim 10, wherein: The accommodating section has a bottom wall surrounding the extending section, the breathable membrane is at least partially clamped between the fixing member and the bottom wall to separate the second through hole and the extending section, and the supporting member is arranged on a side of the breathable membrane away from the extending section.

12. The cap assembly according to any one of claims 1 to 3, wherein: The fixing member has a groove, the groove is arranged around the second through hole, and the breathable membrane is at least partially accommodated in the groove.

13. A battery cell, wherein: include: a housing having an opening; an electrode assembly, contained in the housing; as well as The cap assembly according to any one of claims 1 to 12, wherein the cap assembly is connected to the shell and covers the opening of the shell, and the breathable membrane is located between the electrode assembly and the support member.

14. A battery, wherein: Comprising the battery cell as claimed in claim 13.

15. An electrical device, wherein: Comprising a battery as claimed in claim 14, the battery is used to provide electrical energy.

16. A method for preparing a battery cell, wherein: include: providing a housing having an opening; Providing an electrode assembly, and placing the electrode assembly into the housing; A cover assembly is provided, which includes a cover plate, a fixing member, a breathable membrane and a support member, the cover plate having a first through hole, the fixing member being used to connect the cover plate, the fixing member having a second through hole, the second through hole being configured to be gaseous in communication with the first through hole, the breathable membrane being connected to the fixing member, the breathable membrane being used to cover the second through hole, the support member filling the second through hole and being connected to the fixing member, and the support member being used to support the breathable membrane; the cover assembly is disposed at the opening and connected to the shell through the cover plate, and the gas in the shell passes through the breathable membrane and the fixing member.

17. A device for preparing a battery cell, wherein: include: A first assembly device configured to provide a housing having an opening; a second assembly device configured to provide an electrode assembly and install the electrode assembly into the housing; The third assembly device is configured to provide a cover assembly, which includes a cover plate, a fixing member, a breathable membrane and a support member, the cover plate has a first through hole, the fixing member is used to connect the cover plate, the fixing member has a second through hole, the second through hole is configured to be gas-connected with the first through hole, the breathable membrane is connected to the fixing member, the breathable membrane is used to cover the second through hole, the support member is filled in the second through hole and connected to the fixing member, the support member is used to support the breathable membrane, the cover assembly is set at the opening and connected to the shell through the cover plate, and the gas in the shell passes through the breathable membrane and the fixing member.

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