Battery monomer, battery device and electric equipment

Abstract

The utility model discloses a battery monomer, a battery device and electric equipment. A battery cell includes an electrode assembly, a case, an electrode terminal, a first insulating member, and a second insulating member. The shell comprises a first wall, and the first wall is provided with an electrode lead-out hole. The electrode terminal comprises a terminal body and a first limiting part, at least part of the terminal body is contained in the electrode leading-out hole, and the first limiting part protrudes out of the outer circumferential face of the terminal body. The electrode assembly includes a first tab electrically connected to the electrode terminal and a second tab electrically connected to the first wall. The first insulating member surrounds the terminal body. In the thickness direction of the first wall, at least part of the first insulating component is arranged between the first limiting part and the first wall, at least part of the second insulating component is arranged between the first insulating component and the first limiting part, and the thermal weight loss temperature of the second insulating component is higher than that of the first insulating component.

Description

Technical Field

[0001] This application relates to the field of battery technology, and more specifically, to a battery cell, a battery device, and an electrical appliance. Background Technology

[0002] Battery cells are widely used in electronic devices such as mobile phones, laptops, electric vehicles, electric cars, electric airplanes, electric ships, electric toy cars, electric toy ships, electric toy airplanes, and power tools, etc.

[0003] In the development of battery technology, improving the reliability of individual battery cells is a key research direction. Utility Model Content

[0004] This application provides a battery cell, a battery device, and an electrical appliance that can improve reliability.

[0005] In a first aspect, this application provides a battery cell comprising an electrode assembly, a housing, electrode terminals, a first insulating member, and a second insulating member. The housing includes a first wall and a receiving cavity, the first wall having an electrode lead-out hole communicating with the receiving cavity. The electrode terminal includes a terminal body and a first limiting portion connected to each other, at least a portion of the terminal body being received in the electrode lead-out hole, and at least a portion of the first limiting portion protruding from the outer peripheral surface of the terminal body and located on the side of the first wall facing the receiving cavity. The electrode assembly is received in the receiving cavity, and the electrode assembly includes a first tab and a second tab with opposite polarities, the first tab being electrically connected to the electrode terminal, and the second tab being electrically connected to the first wall. The first insulating member is disposed around the terminal body. In the thickness direction of the first wall, at least a portion of the first insulating member is disposed between the first limiting portion and the first wall. In the thickness direction, at least a portion of the second insulating member is disposed between the first insulating member and the first limiting portion, and the thermal weight loss temperature of the second insulating member is greater than that of the first insulating member.

[0006] By incorporating a first insulating member and a second insulating member, a double-layer insulation structure can be formed between the first wall and the first limiting portion, thereby improving the insulation effect. When a battery cell experiences thermal runaway due to an internal short circuit or other reasons, the battery cell may remain at a high temperature for a period of time. The second insulating member has a higher thermal decomposition temperature than the first insulating member. When the first insulating member experiences weight loss due to high temperature, the second insulating member can remain between the first wall and the first limiting portion, reducing the risk of conduction between the electrode terminals and the first wall. Correspondingly, even if the electrode terminals and the first wall are electrically connected to other battery cells or an external power source, the second insulating member can suppress the current between the electrode terminals and the first wall, reducing the continuous heat generation between the electrode terminals and the first wall, minimizing the thermal impact on surrounding battery cells, reducing the risk of thermal runaway in other battery cells, and improving reliability.

[0007] In some embodiments, the thermal decomposition temperature of the second insulating member is greater than or equal to 300°C. The second insulating member is less prone to weight loss or experiences minimal weight loss during thermal runaway of the battery cell, thereby separating the first limiting portion from the first wall in the event of failure of the first insulating member, reducing the risk of conduction between the electrode terminals and the first wall.

[0008] In some embodiments, the melting point of the second insulating member is higher than that of the first insulating member. In the event of thermal runaway of a battery cell, the second insulating member, with its higher melting point, is less likely to melt, thus remaining between the first limiting portion and the first wall, reducing the risk of insulation failure.

[0009] In some embodiments, the compressive modulus of the first insulating member is less than that of the second insulating member. When the battery cell is subjected to external impact, the second insulating member may vibrate; the first insulating member has a smaller compressive modulus, which can release stress through compressive deformation when the second insulating member vibrates, thereby reducing the risk of cracking of the second insulating member and the risk of insulation failure.

[0010] In some embodiments, the first insulating member includes a first insulating portion and a second insulating portion connected to each other, the second insulating portion being disposed at one end of the first insulating member near the terminal body, and the thickness of the second insulating portion being less than the thickness of the first insulating portion. In the thickness direction of the first wall, at least a portion of the first insulating portion and the second insulating portion are disposed between the first limiting portion and the first wall, and at least a portion of the second insulating member is disposed between the second insulating portion and the first limiting portion.

[0011] By providing a second insulating portion, the space occupied by the first and second insulating components in the thickness direction can be reduced, improving space utilization. During thermal runaway of a battery cell, the internal pressure of the casing increases, and the terminal body may shift outward through the electrode lead-out holes under the influence of this internal pressure. Placing the second insulating portion at the end of the first insulating component near the terminal body allows the second insulating component to be positioned close to the terminal body, thereby constraining the terminal body, reducing the offset of the terminal body under internal pressure, and reducing the deformation of the first limiting portion. This lowers the risk of the first limiting portion contacting the first wall and improves reliability.

[0012] In some embodiments, the distance between the second insulating portion and the first limiting portion in the thickness direction of the first wall is greater than the thickness of the second insulating member. Embodiments of this application can reduce the pressure on the second insulating member, lower the risk of cracking of the second insulating member, and improve reliability.

[0013] In some embodiments, the battery cell includes a seal surrounding a terminal body. At least a portion of the seal is clamped between a first limiting portion and a first wall in the thickness direction. A second insulating member surrounds the seal. The first limiting portion and the first wall can clamp the seal in the thickness direction to seal the electrode lead-out holes. The seal can radially limit the second insulating member, thereby reducing the radial vibration of the second insulating member in the seal when the battery cell is subjected to external impact, and reducing the risk of cracking or failure of the second insulating member.

[0014] In some embodiments, the seal contacts the second insulating member, and the contact surface between the seal and the second insulating member surrounds the terminal body. The seal can radially limit the second insulating member, thereby fixing the second insulating member radially and reducing the risk of the second insulating member cracking or failing when the battery cell is subjected to external impact.

[0015] In some embodiments, a second insulating portion surrounds the seal. A first gap is provided between the seal and the second insulating portion in the radial direction of the seal. In the thickness direction, the projection of the first gap at least partially overlaps with the projection of the second insulating member. By providing the first gap, the risk of overlap between the seal and the second insulating portion in the thickness direction due to assembly errors can be reduced, thereby reducing the risk of interference between the seal and the second insulating portion. The second insulating member can at least partially separate the first gap from the first limiting portion, thereby increasing the creepage distance between the first limiting portion and the first wall, reducing the risk of conduction between the first wall and the first limiting portion, and improving reliability.

[0016] In some embodiments, a second insulating member is disposed between the first insulating portion and the seal in the radial direction of the seal, and a second gap is provided between the second insulating member and the first insulating portion. By providing the second gap, the risk of the second insulating member and the first insulating portion overlapping in the thickness direction due to assembly errors can be reduced, thereby reducing the risk of interference between the second insulating member and the first insulating portion and improving reliability.

[0017] In some embodiments, the first wall includes a wall body and a protrusion, the protrusion protruding from the surface of the wall body facing the receiving cavity, and an electrode lead-out hole is disposed on the protrusion. In the thickness direction, at least a portion of the first insulating portion is disposed between the first limiting portion and the wall body, at least a portion of the second insulating portion is disposed between the first limiting portion and the protrusion, and the second insulating member at least partially overlaps with the protrusion.

[0018] When the second insulating part fails due to thermal runaway of the battery cell, the second insulating member can separate the protrusion from the first limiting part to reduce the risk of the first limiting part contacting the protrusion. The protrusion protrudes from the wall body. By providing the protrusion, the distance between the wall body and the first limiting part can be increased, thereby reducing the risk of the first wall and the first limiting part contacting due to deformation and improving reliability.

[0019] In some embodiments, the first insulating member has a first recess and a second recess, which are respectively disposed on both sides of the second insulating member in the thickness direction. At least a portion of the second insulating member is disposed in the first recess, and at least a portion of the protrusion is disposed in the second recess. By providing the first and second recesses, space can be provided for the protrusion and the second insulating member, thereby improving space utilization.

[0020] In some embodiments, the second insulating member is fixed to at least one of the first insulating member and the first limiting portion. When the battery cell is subjected to external impact, the first insulating member or the first limiting portion can constrain the second insulating member, reduce the vibration of the second insulating member, and reduce the risk of cracking or failure of the second insulating member.

[0021] In some embodiments, the second insulating member surrounds the terminal body, which can increase the insulation area and improve the insulation effect. During thermal runaway of a battery cell, the second insulating member surrounding the terminal body helps to improve the uniformity of force on the first limiting portion, reduce the deformation of the first limiting portion, lower the risk of the first limiting portion contacting the first wall, and improve reliability.

[0022] In some embodiments, the material of the second insulating member is polyimide or ceramic.

[0023] In some embodiments, the thickness of the second insulating member is 0.2 mm to 1.2 mm. Setting the thickness of the second insulating member to be greater than or equal to 0.2 mm increases the distance between the first wall and the first limiting portion in the event of thermal runaway of the battery cell, reducing the risk of contact between the first limiting portion and the first wall. Setting the thickness of the second insulating member to be less than or equal to 1.2 mm saves space occupied by the second insulating member and reduces the impact of the second insulating member on the energy density of the battery cell.

[0024] In some embodiments, the housing further includes a second wall, with the first and second walls located on opposite sides of the electrode assembly. The battery cell includes a pressure relief mechanism disposed on the second wall. By disposing of the electrode terminals and the pressure relief mechanism on opposite sides of the electrode assembly in this application embodiment, the impact on the first and second insulating components can be reduced during the release of high-temperature gases, thereby reducing the risk of failure of the first and second insulating components.

[0025] In some embodiments, the battery cell is a cylindrical battery cell with a diameter greater than or equal to 35 mm and less than or equal to 70 mm.

[0026] Secondly, this application provides a battery device comprising a plurality of battery cells provided in any of the embodiments of the first aspect.

[0027] In some embodiments, at least two battery cells are connected in parallel. In the event of thermal runaway in a battery cell, the normal battery cells connected in parallel with the thermally runaway battery cell may be electrically connected to the first wall and electrode terminals of the thermally runaway battery cell, respectively. The second insulating member can suppress the current between the electrode terminals and the first wall, reduce the continuous heat generation between the electrode terminals and the first wall, reduce the thermal impact on other surrounding battery cells, reduce the risk of thermal runaway in other battery cells, and improve reliability.

[0028] Thirdly, this application provides an electrical device that includes a battery device provided in any embodiment of the second aspect, the battery device being used to provide electrical energy. Attached Figure Description

[0029] The features, advantages, and technical effects of exemplary embodiments of this application will now be described with reference to the accompanying drawings.

[0030] Figure 1 This application provides structural schematic diagrams of vehicles for some embodiments;

[0031] Figure 2 Schematic diagram of a battery device provided for some embodiments of this application;

[0032] Figure 3 for Figure 2 The diagram shows the structure of the battery module.

[0033] Figure 4 This is a schematic diagram of the structure of a single battery cell in some embodiments of this application;

[0034] Figure 5 for Figure 4 The diagram shows an exploded battery cell;

[0035] Figure 6 This is a cross-sectional schematic diagram of the electrode assembly of a battery cell provided in some embodiments of this application;

[0036] Figure 7 A schematic diagram of the positive electrode sheet of the electrode assembly of a battery cell provided in some embodiments of this application after being unfolded;

[0037] Figure 8 A schematic diagram of the negative electrode sheet of the electrode assembly of a battery cell provided in some embodiments of this application after being unfolded;

[0038] Figure 9 A cross-sectional schematic diagram of a battery cell provided in some embodiments of this application;

[0039] Figure 10 for Figure 9 An enlarged view of box A;

[0040] Figure 11 for Figure 10 Enlarged view of the area within the circle;

[0041] Figure 12 for Figure 11 Enlarged illustration within the box;

[0042] Figure 13 for Figure 9 Enlarged view at box B;

[0043] Figure 14 Partial cross-sectional schematic diagram of a battery cell provided for other embodiments of this application;

[0044] Figure 15 Explosion-proof diagrams of individual battery cells provided in other embodiments of this application;

[0045] Figure 16 Partial cross-sectional schematic diagram of a battery cell provided for other embodiments of this application;

[0046] Figure 17 This is a simplified schematic diagram of a battery device provided for other embodiments of this application.

[0047] The annotations in the attached figures are explained as follows:

[0048] 1. Vehicle; 2. Battery unit; 3. Controller; 4. Motor; 5. Housing; 5a. First housing; 5b. Second housing; 6. Battery module; 7. Battery cell; 7a. Battery unit; 8. Busbar component;

[0049] 10. Electrode assembly; 10a. First tab; 10b. Second tab; 10c. Electrode body; 10d. First through hole; 11. Positive electrode plate; 111. Positive current collector; 1111. Positive tab; 112. Positive electrode film; 12. Negative electrode plate; 121. Negative current collector; 1211. Negative tab; 122. Negative electrode film; 13. Separator;

[0050] 20. Outer shell; 20a. Second wall; 20b. Receiving cavity; 21. Shell; 211. First wall; 2111. Electrode lead-out hole; 2112. Wall body; 2113. Protrusion; 2114. Third recess; 212. Side wall; 2121. Side wall protrusion; 2122. Side wall recess; 2123. Press-fit part; 22. End cap;

[0051] 30. Electrode terminal; 31. Terminal body; 311. Second through hole; 32. First limiting part; 33. Second limiting part; 34. Terminal recess;

[0052] 40. First insulating member; 41. First insulating portion; 42. Second insulating portion; 43. First recess; 44. Second recess;

[0053] 50. Second insulating component; 60. Sealing component; 70. Third insulating component

[0054] 80. Pressure relief mechanism; 81. Pressure relief section; 82. Weak section; 83. Fourth recess;

[0055] 90. Electrode lead-out section; 91. First current collector; 92. Cover plate; 93. Sealing pin; 94. Second current collector; 95. Fourth insulating component;

[0056] G1, first gap; G2, second gap;

[0057] V, winding direction; Z, thickness direction. Detailed Implementation

[0058] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0059] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used in the description of this application is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms "comprising" and "having," and any variations thereof, in the description, claims, and accompanying drawings of this application are intended to cover non-exclusive inclusion. The terms "first," "second," etc., in the description, claims, or accompanying drawings of this application are used to distinguish different objects, not to describe a specific order or hierarchy.

[0060] In this application, the reference to "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment that is mutually exclusive with other embodiments.

[0061] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "attachment" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0062] In this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, in this application, the character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0063] In the embodiments of this application, the same reference numerals denote the same components, and for the sake of brevity, detailed descriptions of the same components are omitted in different embodiments. It should be understood that the thickness, length, width, and other dimensions of various components in the embodiments of this application shown in the accompanying drawings, as well as the overall thickness, length, width, and other dimensions of the integrated device, are merely illustrative and should not constitute any limitation on this application.

[0064] In this application, "multiple" means two or more (including two).

[0065] Currently, judging from market trends, battery applications are becoming increasingly widespread. Batteries are not only used in energy storage systems such as hydropower, thermal power, wind power, and solar power plants, but also extensively in electric vehicles such as electric bicycles, electric motorcycles, and electric cars, as well as in aerospace and other fields. With the continuous expansion of battery applications, market demand is also constantly increasing.

[0066] A battery device typically refers to a single physical module comprising multiple battery cells to provide higher voltage and capacity. A battery cell can be the smallest unit that makes up a battery device.

[0067] A battery cell typically includes a casing, an electrode assembly housed within the casing, and a positive electrode lead and a negative electrode lead disposed on the casing. The electrode assembly typically includes a positive electrode plate and a negative electrode plate, with the positive electrode lead electrically connected to the positive electrode plate and the negative electrode lead electrically connected to the negative electrode plate. The positive and negative electrode leads are used for electrical connection to an external circuit to enable charging or discharging of the battery cell.

[0068] In some embodiments, a single battery cell includes electrode terminals; one of the positive electrode lead and the negative electrode lead includes electrode terminals, and the other includes the shell wall of the outer casing.

[0069] When a battery cell in a battery device experiences thermal runaway due to an accident (such as an internal short circuit), that battery cell may remain at a high temperature for a period of time. At this high temperature, the insulating components used to insulate the electrode terminals and the casing may fail, causing current from other battery cells or from an external power source to continuously flow between the electrode terminals and the casing. This results in continuous localized heat generation in the affected battery cell, potentially triggering abnormal temperature increases and thermal runaway in other normal battery cells, leading to heat propagation.

[0070] For example, when a conductive path is formed between the electrode terminals and the casing of the battery cell, a closed loop is formed between the battery cell and the battery cells connected in parallel with the battery cell, and current will continuously flow through the battery cell, causing the battery cell to generate heat locally.

[0071] In view of this, the present application provides a battery cell that, by providing an insulating member with a high thermal runaway temperature between the electrode terminals and the casing, reduces the risk of conduction between the electrode terminals and the casing when the battery cell experiences thermal runaway, reduces the continuous heat generation of the thermally runaway battery cell, reduces the risk of thermal runaway in other battery cells, and improves reliability.

[0072] The battery cells described in this application are applicable to battery devices and electrical equipment using battery devices. Electrical equipment can be devices that use battery devices as a power source or various energy storage systems that use battery devices as energy storage elements. Electrical equipment can be, but is not limited to, mobile phones, tablets, laptops, electric toys, power tools, electric vehicles, electric cars, ships, spacecraft, etc. Electric toys can include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc. Spacecraft can include airplanes, rockets, space shuttles, and spacecraft, etc.

[0073] For ease of explanation, the following embodiments use a vehicle as an example of electrical equipment.

[0074] Figure 1 The diagram shows the structural features of a vehicle provided in some embodiments of this application.

[0075] like Figure 1 As shown, a battery device 2 is installed inside the vehicle 1. The battery device 2 can be located at the bottom, front, or rear of the vehicle 1. The battery device 2 can be used to power the vehicle 1; for example, the battery device 2 can serve as the operating power source for the vehicle 1.

[0076] The vehicle 1 may also include a controller 3 and a motor 4. The controller 3 is used to control the battery device 2 to supply power to the motor 4, for example, for the power needs of the vehicle 1 during starting, navigation and driving.

[0077] In some embodiments of this application, the battery device 2 can not only serve as the operating power source for the vehicle 1, but also as the driving power source for the vehicle 1, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1.

[0078] Figure 2 A schematic diagram of a battery device provided for some embodiments of this application.

[0079] In some embodiments, the battery device 2 may include one or more battery cell assemblies for providing voltage and capacity.

[0080] A battery cell assembly may include multiple battery cells ( Figure 2 (Not shown), multiple battery cells are connected in series, parallel, or mixed connection through a busbar. Mixed connection refers to multiple battery cells being connected in both series and parallel.

[0081] A battery cell can be a rechargeable battery cell, which refers to a battery cell that can be recharged after being discharged to activate the active materials and continue to be used.

[0082] As an example, a single battery cell can be a lithium-ion battery cell, a sodium-ion battery cell, a sodium-lithium-ion battery cell, a lithium metal battery cell, a sodium metal battery cell, a lithium-sulfur battery cell, a magnesium-ion battery cell, a nickel-metal hydride battery cell, a nickel-cadmium battery cell, a lead-acid battery cell, etc.

[0083] As an example, a battery cell can be a prismatic battery cell, a pouch battery cell, or a battery cell of other shapes. Prismatic battery cells include prismatic battery cells, blade-shaped battery cells, and multi-prismatic battery cells, such as hexagonal prismatic battery cells.

[0084] In some embodiments, a battery cell assembly is typically formed by arranging multiple battery cells; as an example, a battery cell assembly can be a battery module 6, which is formed by arranging and fixing multiple battery cells into a single module. As an example, a battery module 6 can be formed by bundling multiple battery cells together with cable ties.

[0085] In some embodiments, the battery device 2 may be a battery pack, which includes a housing 5 and one or more battery cell assemblies housed within the housing 5. As an example, the battery cell assembly may be a battery module 6, which can be housed within the housing by securing the battery module 6 to the housing. Alternatively, the battery cell assembly may be housed within the housing by directly securing multiple battery cells to the housing.

[0086] In some embodiments, the housing 5 is used to house individual battery cells, and the housing 5 can have various structures.

[0087] In some embodiments, the housing 5 may include a first housing 5a and a second housing 5b. The first housing 5a and the second housing 5b are fastened together to form a closed space inside the housing 5 to house the battery cell assembly. Here, "closed" refers to covering or closing, and can be either sealed or unsealed. The first housing may be a top cover or a bottom plate.

[0088] In some embodiments, the housing 5 may include a top cover, a frame, and a bottom plate. The top cover and bottom plate are respectively connected to the frame, forming an enclosed space inside the housing to accommodate individual battery cells. As an example, the frame may include multiple side beams.

[0089] In some embodiments, the housing 5 may be part of the vehicle's chassis structure. For example, a portion of the housing 5 may be at least a portion of the vehicle's floor, or a portion of the housing 5 may be at least a portion of the vehicle's crossbeams and longitudinal beams.

[0090] In some embodiments, the battery device 2 may be an energy storage device.

[0091] Energy storage devices can be used in energy storage power stations, wind power generation systems, solar power generation systems, mobile power systems, or temporary power supply systems. Energy storage devices can store electrical energy as needed and output it when appropriate. For example, energy storage devices can store electrical energy during off-peak hours and provide power to relevant users or electrical equipment during peak hours.

[0092] In some embodiments, the energy storage device includes an energy storage container, an energy storage cabinet, etc.

[0093] Figure 3 for Figure 2 The diagram shows the structure of the battery module.

[0094] In some embodiments, such as Figure 3 As shown, there are multiple battery cells 7, which are first connected in series, parallel, or a combination of both to form a battery module 6. These battery modules 6 are then connected in series, parallel, or a combination of both to form a whole, which is housed within the casing.

[0095] Multiple battery cells 7 in battery module 6 can be electrically connected through a busbar to achieve parallel, series, or mixed connection of multiple battery cells 7 in battery module 6. There can be one or more busbars, each used to electrically connect at least two battery cells 7.

[0096] Figure 4 This is a schematic diagram of the structure of a single battery cell in some embodiments of this application; Figure 5 for Figure 4 The diagram shows an exploded battery cell; Figure 6 This is a cross-sectional schematic diagram of the electrode assembly of a battery cell provided in some embodiments of this application;

[0097] Figure 7 A schematic diagram of the positive electrode sheet of the electrode assembly of a battery cell provided in some embodiments of this application after being unfolded; Figure 8 This is a schematic diagram of the negative electrode sheet of the electrode assembly of a battery cell provided in some embodiments of this application after being unfolded.

[0098] Reference Figures 4 to 8 This application provides a battery cell 7, which includes a housing 20 and an electrode assembly 10 housed within the housing 20.

[0099] In some embodiments, the outer casing 20 may be a steel casing, an aluminum casing, or a composite metal casing (such as a copper-aluminum composite casing).

[0100] The outer shell 20 may be a hollow structure, with an internal cavity 20b for accommodating the electrode assembly 10 and the electrolyte.

[0101] In some embodiments, the casing 20 of the battery cell 7 is a cylindrical casing, a square casing, a prismatic casing, or a casing of other shapes.

[0102] In some embodiments, the housing 20 includes a housing 21 and an end cap 22, the housing 21 having an opening, and the end cap 22 being connected to the housing 21 and covering the opening;

[0103] The housing 21 is a component used to fit the end cap 22 to form the internal cavity of the battery cell 7. The formed internal cavity can be used to accommodate the electrode assembly 10, the electrolyte, and other components.

[0104] The housing 21 and the end cap 22 can be separate components. For example, an opening can be provided on the housing 21, and the end cap 22 can be used to close the opening to form an internal cavity for the battery cell 7.

[0105] The housing 21 can be of various shapes and sizes, such as cuboid or cylindrical. Specifically, the shape of the housing 21 can be determined according to the specific shape and size of the electrode assembly 10. The housing 21 can be made of various materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, etc.

[0106] The shape of the end cap 22 can be adapted to the shape of the housing 21 to fit the housing 21. The material of the end cap 22 can be the same as or different from the material of the housing 21. Optionally, the end cap 22 can be made of a material with a certain hardness and strength (such as copper, iron, aluminum, stainless steel, aluminum alloy, etc.), so that the end cap 22 is not easily deformed when subjected to compression and impact, so that the battery cell 7 can have higher structural strength and improve reliability.

[0107] The end cap 22 is connected to the housing 21 by welding, bonding, snap-fitting or other means.

[0108] The housing 21 may be open at one end or open at both ends. In some examples, the housing 21 may be a structure with an opening on one side, and one end cap 22 is provided to cover the housing 21. In other examples, the housing 21 may also be a structure with openings on both sides, and two end caps 22 are provided, with the two end caps 22 respectively covering the two openings of the housing 21.

[0109] Electrode assembly 10 is a component in the battery cell 7 where electrochemical reactions occur. The housing 21 may contain one or more electrode assemblies 10.

[0110] In some embodiments, the electrode assembly 10 includes a positive electrode 11, a negative electrode 12, and a separator 13, wherein the positive electrode 11 and the negative electrode 12 have opposite polarities, and the separator 13 separates the positive electrode 11 and the negative electrode 12.

[0111] At least a portion of the separator 13 is located between the positive electrode 11 and the negative electrode 12. During the charging and discharging process of the battery cell 7, active ions (e.g., lithium ions) repeatedly insert and extract between the positive electrode 11 and the negative electrode 12. The separator 13, located between the positive electrode 11 and the negative electrode 12, serves to prevent short circuits between the positive and negative electrodes while allowing active ions to pass through.

[0112] In some embodiments, the positive electrode 11 may include a positive current collector 111 and a positive electrode film layer 112 disposed on at least one surface of the positive current collector 111.

[0113] As an example, the positive current collector 111 has two surfaces opposite each other in its own thickness direction, and the positive electrode film layer 112 is disposed on either or both of the two opposite surfaces of the positive current collector 111.

[0114] As an example, the positive current collector 111 can be made of metal foil, conductive polymer material, carbon material, or composite current collector. For example, as a metal foil, pure metal, alloy, or surface-treated metal can be used, including but not limited to stainless steel, copper, aluminum, nickel, nickel alloy, titanium, or silver. The composite current collector may include a polymer material base layer and a metal layer. The composite current collector can be formed by forming a metal material (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0115] As an example, the positive electrode film 112 includes a positive electrode active material, which may include at least one of the following materials: lithium phosphate, lithium transition metal oxide, and their respective modified compounds. However, this application is not limited to these materials, and other conventional materials that can be used as positive electrode active materials for batteries may also be used. These positive electrode active materials may be used alone or in combination of two or more. Examples of lithium phosphate include, but are not limited to, at least one of lithium iron phosphate (such as LiFePO4 (also referred to as LFP)), lithium iron phosphate and carbon composites, lithium manganese phosphate (such as LiMnPO4), lithium manganese phosphate and carbon composites, lithium iron manganese phosphate, and lithium iron manganese phosphate and carbon composites. Examples of lithium transition metal oxides include, but are not limited to, lithium cobalt oxide (such as LiCoO2), lithium nickel oxide (such as LiNiO2), lithium manganese oxide (such as LiMnO2, LiMn2O4), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, and lithium nickel cobalt manganese oxide (such as LiNi). 1 / 3 Co 1 / 3 Mn 1 / 3 O2 (also known as NCM) 333 LiNi 0.5 Co 0.2 Mn 0.3 O2 (also known as NCM) 523 LiNi 0.5 Co 0.25 Mn 0.25 O2 (also known as NCM) 211 LiNi 0.6 Co 0.2 Mn 0.2 O2 (also known as NCM) 622 LiNi 0.8 Co 0.1 Mn 0.1 O2 (also known as NCM) 811 ), lithium nickel cobalt aluminum oxide (such as LiNi) 0.8 Co 0.15 Al 0.05 At least one of O2 and its modified compounds. Modified compounds refer to substances obtained by modification methods such as doping or coating based on the above-mentioned substances.

[0116] In some embodiments, the negative electrode 12 may include a negative current collector 121.

[0117] As an example, the negative electrode current collector 121 can be made of metal foil, conductive polymer material, carbon material, or composite current collector. For example, as a metal foil, pure metal, alloy, or surface-treated metal can be used, including but not limited to stainless steel, copper, aluminum, nickel, nickel alloy, titanium, or silver. The composite current collector may include a polymer material substrate and a metal layer. The composite current collector can be formed by forming a metal material (copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0118] As an example, the negative electrode 12 may include a negative electrode current collector 121 and a negative electrode film layer 122 disposed on at least one surface of the negative electrode current collector 121.

[0119] As an example, the negative electrode current collector 121 has two surfaces opposite each other in its own thickness direction, and the negative electrode film layer 122 is disposed on either or both of the two opposite surfaces of the negative electrode current collector 121.

[0120] As an example, the negative electrode film 122 includes a negative electrode active material, which may be a negative electrode active material known in the art for use in battery cells. As an example, the negative electrode active material may include at least one of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, and lithium titanate, etc. Silicon-based materials may be selected from at least one of elemental silicon, silicon oxide compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. Tin-based materials may be selected from at least one of elemental tin, tin oxide compounds, and tin alloys. However, this application is not limited to these materials, and other conventional materials that can be used as negative electrode active materials in battery cells may also be used. These negative electrode active materials may be used alone or in combination of two or more.

[0121] In some embodiments, the positive current collector 111 may be made of aluminum, and the negative current collector 121 may be made of copper.

[0122] In some embodiments, the separator 13 includes a separator membrane. The separator membrane of this application can be any known porous membrane with good chemical and mechanical stability.

[0123] As an example, the main material of the separator can be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene, polyvinylidene fluoride, and ceramics. The separator can be a single-layer film or a multi-layer composite film, without particular limitation. When the separator is a multi-layer composite film, the materials of each layer can be the same or different.

[0124] Inorganic particle coating, organic particle coating, or organic / inorganic composite coating can also be applied to the surface of the separator.

[0125] The separator 13 can be a single component located between the positive electrode 11 and the negative electrode 12, or it can be attached to the surface of the positive electrode 11 or the surface of the negative electrode 12.

[0126] In some embodiments, the separator 13 is a solid electrolyte. The solid electrolyte is disposed between the positive electrode 11 and the negative electrode 12, and serves to both transport ions and isolate the positive and negative electrodes.

[0127] In some embodiments, the battery cell 7 further includes an electrolyte that acts as a conductor of ions between the positive electrode 11 and the negative electrode 12. The electrolyte used in this application can be selected according to requirements. The electrolyte can be liquid, gel, or solid.

[0128] In some embodiments, the liquid electrolyte includes an electrolyte salt and a solvent.

[0129] In some embodiments, the electrolyte salt may be selected from at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluorooxalate borate, lithium dioxalate borate, lithium difluorodioxalate phosphate, and lithium tetrafluorooxalate phosphate.

[0130] In some embodiments, the solvent may be selected from at least one of ethylene carbonate, propylene carbonate, methyl ethyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, butyl carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, sulfolane, dimethyl sulfone, methyl ethyl sulfone, and diethyl sulfone. The solvent may also be an ether solvent. Ether solvents may include one or more of ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, 1,3-dioxolane, tetrahydrofuran, methyl tetrahydrofuran, diphenyl ether, and crown ethers.

[0131] In some embodiments, the electrolyte may optionally include additives. For example, additives may include negative electrode film-forming additives, positive electrode film-forming additives, and additives that can improve certain properties of the battery cell, such as additives that improve the overcharge / fast charge performance of the battery cell, additives that improve the high-temperature performance of the battery cell, and additives that improve the low-temperature performance of the battery cell.

[0132] In some embodiments, the gel electrolyte comprises a polymer as a backbone network and can be used in conjunction with an ionic liquid-lithium salt.

[0133] In some embodiments, the solid electrolyte includes a polymer solid electrolyte, an inorganic solid electrolyte, and a composite solid electrolyte.

[0134] As an example, the polymers of polymeric solid electrolytes may include polyethers (polyoxyethylene), polysiloxanes, polycarbonates, polyacrylonitrile, polyvinylidene fluoride, polymethyl methacrylate, monoionic polymers, polyionic liquids, cellulose, etc.

[0135] As an example, inorganic solid electrolytes can be one or more of the following: oxide solid electrolytes (crystalline perovskite, sodium superconducting ion conductor, garnet, amorphous LiPON thin film), sulfide solid electrolytes (crystalline lithium superconducting ion conductor (lithium germanium phosphorus sulfide, silver sulfide germanium ore), amorphous sulfides), halide solid electrolytes, nitride solid electrolytes, and hydride solid electrolytes.

[0136] As an example, composite solid electrolytes are formed by adding inorganic solid electrolyte fillers to polymer solid electrolytes.

[0137] In some embodiments, the electrode assembly 10 can be a wound structure, a stacked structure, or a hybrid structure of wound and stacked.

[0138] In some embodiments, the electrode assembly 10 is a wound structure. The positive electrode 11 and the negative electrode 12 are wound into a wound structure.

[0139] In some embodiments, the electrode assembly 10 has a stacked structure.

[0140] As an example, multiple positive electrode plates 11 and multiple negative electrode plates 12 can be provided, with multiple positive electrode plates 11 and multiple negative electrode plates 12 being stacked alternately. As an example, multiple positive electrode plates 11 can be provided, and multiple negative electrode plates 12 can be folded to form multiple stacked folded segments, with a positive electrode plate 11 sandwiched between adjacent folded segments.

[0141] As an example, both the positive electrode 11 and the negative electrode 12 are folded to form multiple stacked folded segments.

[0142] As an example, multiple separators 13 can be provided, respectively disposed between any adjacent positive electrode 11 or negative electrode 12.

[0143] As an example, the separator 13 can be continuously arranged and disposed between any adjacent positive electrode 11 or negative electrode 12 by means of folding or rolling.

[0144] In some embodiments, the electrode assembly 10 may be cylindrical, flat, or polygonal in shape.

[0145] In some embodiments, the positive current collector 111 may include a positive tab 1111, and the negative current collector 121 may include a negative tab 1211. The positive tab 1111 and the negative tab 1211 can be used to transmit current. As an example, at least a portion of the positive tab 1111 is not coated with the positive electrode film 112, and at least a portion of the negative tab 1211 is not coated with the negative electrode film 122.

[0146] In some embodiments, the electrode assembly 10 has a wound structure. The positive electrode tab 1111 is wound multiple turns along the winding direction V. Optionally, the end of the positive electrode tab 1111 is bent by a flattening or smoothing process to form a multi-layer structure stacked in the axial direction of the electrode assembly 10. Optionally, the positive electrode tab 1111 is annular.

[0147] In some embodiments, the negative electrode tab 1211 is wound multiple turns along the winding direction V. Optionally, the ends of the negative electrode tab 1211 are bent by a flattening or smoothing process to form a multilayer structure stacked in the axial direction of the electrode assembly 10. The negative electrode tab 1211 is annular.

[0148] In some embodiments, the electrode assembly 10 includes an electrode body 10c. As an example, the electrode body 10c includes a positive electrode film 112, a portion of a positive electrode current collector 111 covered by the positive electrode film 112, a negative electrode film 122, a portion of a negative electrode current collector 121 covered by the negative electrode film 122, and a separator 13.

[0149] The positive tab 1111 and the negative tab 1211 can be led out from the same end of the electrode body 10c, or they can be led out from opposite ends of the electrode body 10c. At least a portion of the positive tab 1111 protrudes to the outside of the insulating member 13, and at least a portion of the negative tab 1211 protrudes to the outside of the insulating member 13.

[0150] Figure 9 A cross-sectional schematic diagram of a battery cell provided in some embodiments of this application; Figure 10 for Figure 9 An enlarged view of box A; Figure 11 for Figure 10 Enlarged view of the area within the circle; Figure 12 for Figure 11 Enlarged illustration within the box; Figure 13 for Figure 9 Enlarged view of box B.

[0151] Reference Figures 4 to 13This application provides a battery cell 7, which includes an electrode assembly 10, a housing 20, electrode terminals 30, a first insulating member 40, and a second insulating member 50. The housing 20 includes a first wall 211 and a receiving cavity 20b. The first wall 211 has an electrode lead-out hole 2111 communicating with the receiving cavity 20b. The electrode terminals 30 include terminal bodies 31 and a first limiting portion 32 connected to each other. At least a portion of the terminal body 31 is received in the electrode lead-out hole 2111. At least a portion of the first limiting portion 32 protrudes from the outer peripheral surface of the terminal body 31 and is located on the side of the first wall 211 facing the receiving cavity 20b.

[0152] In the thickness direction Z of the first wall 211, at least a portion of the first insulating member 40 is disposed between the first limiting portion 32 and the first wall 211. In the thickness direction Z, at least a portion of the second insulating member 50 is disposed between the first insulating member 40 and the first limiting portion 32. The thermal weight loss temperature of the second insulating member 50 is greater than that of the first insulating member 40.

[0153] As an example, the first wall 211 can be an end cap 22 or a wall of the housing 21.

[0154] One of the first electrode tab 10a and the second electrode tab 10b is a positive electrode tab 1111, and the other is a negative electrode tab 1211. The polarity of the electrode terminal 30 corresponds to the polarity of the first electrode tab 10a. In some examples, the first electrode tab 10a is a positive electrode tab 1111, and the electrode terminal 30 is a positive terminal; in other examples, the first electrode tab 10a is a negative electrode tab 1211, and the electrode terminal 30 is a negative terminal.

[0155] As an example, the first tab 10a and the second tab 10b can be disposed at the same end of the electrode assembly 10, or they can be disposed at opposite ends of the electrode assembly 10.

[0156] The first tab 10a can be directly connected to the electrode terminal 30, or it can be indirectly connected to the electrode terminal 30 through other conductive structures.

[0157] The second tab 10b can be directly connected to the first wall 211, or it can be indirectly connected to the first wall 211 through other conductive structures.

[0158] Electrode lead-out hole 2111 penetrates the first wall 211. As an example, along the thickness direction Z of the first wall 211, the electrode lead-out hole 2111 penetrates the first wall 211, and the projection of the electrode terminal 30 at least partially overlaps with the projection of the electrode lead-out hole 2111.

[0159] As an example, the electrode lead-out hole 2111 can be a round hole, a square hole, a racetrack-shaped hole, an elliptical hole, or a hole of other shapes.

[0160] The electrode terminal 30 is insulated from the first wall 211.

[0161] In some examples, the first limiting part 32 and the terminal body 31 can be integrally formed. In other examples, the first limiting part 32 and the terminal body 31 are formed independently and connected by welding, riveting, bonding or other means.

[0162] In the thickness direction Z of the first wall 211, the first limiting portion 32 at least partially overlaps with the first wall 211. The first wall 211 and the first limiting portion 32 can limit each other in the thickness direction Z, thereby improving the stability of the electrode terminal 30.

[0163] At least a portion of the first insulating member 40 is disposed between the electrode terminal 30 and the first wall 211 to insulate and isolate at least a portion of the electrode terminal 30 from the first wall 211.

[0164] In the thickness direction Z of the first wall 211, the first insulating member 40 can be integrally disposed between the first limiting part 32 and the first wall 211, or it can be partially disposed between the first limiting part 32 and the first wall 211.

[0165] Exemplarily, the second insulating member 50 may extend circumferentially around the terminal body 31. For example, the second insulating member 50 may surround the terminal body 31. Alternatively, the second insulating member 50 may extend less than one circumference around the terminal body 31. In some examples, there may be multiple second insulating members 50, which may be arranged at circumferential intervals around the terminal body 31.

[0166] In the thickness direction Z, the second insulating member 50 can be integrally disposed between the first limiting part 32 and the first insulating member 40, or it can be partially disposed between the first limiting part 32 and the first insulating member 40.

[0167] The second insulating member 50 can be in contact with the first insulating member 40, or they can be spaced apart in the thickness direction Z.

[0168] The second insulating member 50 can contact the first limiting part 32, or they can be spaced apart in the thickness direction Z.

[0169] For example, the thermogravimetric temperature of the first insulating component 40 can be the 5% thermogravimetric temperature; the 5% thermogravimetric temperature can be the temperature at which the mass of the test sample is lost by 5% relative to the initial mass in thermogravimetric analysis. The thermogravimetric temperature of the first insulating component 40 can be measured with reference to GB / T27761-2011 Test Method for Weight Loss and Residual Weight of Thermogravimetric Analyzer.

[0170] For example, the thermogravimetric temperature of the second insulating member 50 can be the 5% thermogravimetric temperature. The thermogravimetric temperature of the second insulating member 50 can be measured with reference to GB / T27761-2011 Test Method for Weight Loss and Residual Weight by Thermogravimetric Analyzer.

[0171] By providing the first insulating member 40 and the second insulating member 50, a double-layer insulation structure can be formed between the first wall 211 and the first limiting part 32, thereby improving the insulation effect. When the battery cell 7 experiences thermal runaway due to internal short circuit or other reasons, the battery cell 7 may remain at a high temperature for a period of time. The second insulating member 50 has a higher thermal weight loss temperature than the first insulating member 40. When the first insulating member 40 experiences weight loss due to high temperature, the second insulating member 50 can remain between the first wall 211 and the first limiting part 32, reducing the risk of conduction between the electrode terminal 30 and the first wall 211. Correspondingly, even if the electrode terminal 30 and the first wall 211 are electrically connected to other battery cells 7 or an external power source, the second insulating member 50 can suppress the current between the electrode terminal 30 and the first wall 211, reduce the continuous heat generation between the electrode terminal 30 and the first wall 211, reduce the thermal impact on other surrounding battery cells 7, reduce the risk of thermal runaway in other battery cells 7, and improve reliability.

[0172] For example, when the first wall 211 and electrode terminal 30 of a normal battery cell 7 are electrically connected to the first wall 211 and electrode terminal 30 of a thermally runaway battery cell 7, even if the first insulating member 40 experiences weight loss or other problems due to high temperature, the second insulating member 50 can cut off the circuit between the two battery cells 7, reduce the continuous heat generation of the electrode terminal 30 and the first wall 211 of the thermally runaway battery cell 7, reduce the thermal impact on other surrounding battery cells 7, reduce the risk of thermal runaway in other battery cells 7, and improve reliability.

[0173] The first wall 211 and the electrode terminal 30 can serve as two electrodes of the battery cell 7 and are located on the same side of the battery cell 7. When multiple battery cells 7 are assembled into a group, it facilitates the connection between the busbar and the first wall 211 or the busbar and the electrode terminal 30, simplifying the structure of the battery device. Although the first wall 211 and the electrode terminal 30 have opposite polarities, the second insulating member 50 can also suppress the current between the first wall 211 and the electrode terminal 30 in the event of thermal runaway of the battery cell 7, reducing the continuous heat generation between the electrode terminal 30 and the first wall 211 and improving reliability.

[0174] In some embodiments, the thermal weight loss temperature of the second insulating member 50 is greater than or equal to 300°C. The second insulating member 50 is less prone to weight loss or experiences minimal weight loss during thermal runaway of the battery cell 7, thereby separating the first limiting portion 32 from the first wall 211 when the first insulating member 40 fails, reducing the risk of conduction between the electrode terminal 30 and the first wall 211.

[0175] As an example, the thermal decomposition temperature of the second insulating member 50 may be 300°C, 350°C, 400°C, 450°C, 500°C, 550°C, 600°C, 650°C, 700°C, 750°C, 800°C, 850°C, 900°C, 950°C, 1000°C, 1200°C, 1400°C, 1500°C, or 1600°C.

[0176] In some embodiments, the thermal weight loss temperature of the second insulating member 50 is greater than or equal to 350°C, which can further reduce the weight loss rate of the second insulating member 50 during thermal runaway of the battery cell 7, reduce the risk of failure of the second insulating member 50, reduce the continuous heat generation of the electrode terminal 30 and the first wall 211, reduce the thermal impact on other battery cells 7 in the surrounding area, reduce the risk of thermal runaway of other battery cells 7, and improve reliability.

[0177] In some embodiments, the thermal weight loss temperature of the second insulating member 50 is greater than or equal to 500°C, which can further reduce the weight loss rate of the second insulating member 50 during thermal runaway of the battery cell 7, reduce the risk of failure of the second insulating member 50, reduce the continuous heat generation of the electrode terminal 30 and the first wall 211, reduce the thermal impact on other battery cells 7 in the surrounding area, reduce the risk of thermal runaway of other battery cells 7, and improve reliability.

[0178] In some embodiments, the thermal weight loss temperature of the second insulating member 50 is greater than or equal to 550°C.

[0179] In some embodiments, the melting point of the second insulating member 50 is higher than that of the first insulating member 40. In the event of thermal runaway of the battery cell 7, the second insulating member 50, having a higher melting point, is less likely to melt, thereby remaining between the first limiting portion 32 and the first wall 211, reducing the risk of insulation failure.

[0180] In some embodiments, the melting point of the second insulating member 50 is greater than or equal to 400°C. Exemplarily, the melting point of the second insulating member 50 is 400°C, 450°C, 500°C, 550°C, 600°C, 650°C, 700°C, 750°C, 800°C, 850°C, 900°C, 950°C, 1000°C, 1200°C, 1400°C, 1500°C, or 1600°C.

[0181] In some embodiments, the material of the second insulating member 50 includes a thermosetting material.

[0182] Thermosetting materials possess excellent heat resistance, maintaining good stability at high temperatures and resisting softening, deformation, or decomposition. During thermal runaway of the battery cell 7, the internal pressure of the casing 20 increases, and the pressure on the second insulating member 50 also increases. The second insulating member 50, containing thermosetting materials, is less prone to softening at high temperatures, thus reducing deformation under pressure. This constrains the offset of the terminal body 31 and the deformation of the first limiting portion 32, improving insulation performance and reducing the risk of insulation failure.

[0183] In some embodiments, the thermosetting material may include at least one of thermosetting polyimide, thermosetting phenolic resin, or other high-temperature resistant thermosetting materials.

[0184] In some embodiments, the material of the second insulating member 50 includes one or more thermosetting polyimides and their derivatives.

[0185] For example, a derivative can refer to a product derived from the substitution of hydrogen atoms or groups of atoms in a polymer by other atoms or groups of atoms.

[0186] Thermosetting polyimide exhibits excellent heat resistance. In the event of thermal runaway of the battery cell 7, the second insulating component 50, which contains thermosetting polyimide, maintains good performance stability at high temperatures, exhibiting minimal or no weight loss, thereby reducing the risk of insulation failure.

[0187] Thermosetting polyimide has high strength. In the event of thermal runaway of the battery cell 7, the second insulating member 50 containing thermosetting polyimide can withstand a large load and is not easily cracked or punctured under the pressure of the first limiting part 32, thereby reducing the risk of insulation failure.

[0188] Thermosetting polyimide exhibits low creep. During the long-term use of the battery cell 7, the second insulating member 50 containing thermosetting polyimide shows minimal creep, and its size and shape maintain good stability, thereby reducing the risk of insulation failure.

[0189] Thermosetting polyimide has good corrosion resistance. During the assembly or use of the battery cell 7, the second insulating component 50 containing thermosetting polyimide is not easily corroded by the electrolyte, thereby reducing the risk of insulation failure.

[0190] In some embodiments, the material of the second insulating member 50 includes one or more of bismaleimide, ethynyl-terminated polyimide, and norbornene-terminated polyimide.

[0191] In some embodiments, the material of the second insulating member 50 includes ceramic.

[0192] For example, the second insulating member 50 may be made of aluminum oxide, titanium oxide, silicon oxide, zirconium oxide, glass, etc.

[0193] The ceramic has good thermal stability and can withstand high temperatures. In the event of thermal runaway of the battery cell 7, the second insulating component 50 made of ceramic can be kept between the first wall 211 and the first limiting part 32, reducing the risk of conduction between the electrode terminal 30 and the first wall 211 and improving reliability.

[0194] In some embodiments, the material of the second insulating member 50 is polyimide or ceramic.

[0195] In some embodiments, the material of the first insulating member 40 includes a thermoplastic material.

[0196] Thermoplastic materials have advantages such as easy molding, good flexibility, high chemical stability, and excellent electrical insulation.

[0197] The first insulating member 40, which contains thermoplastic material, is easy to mold, and its shape can be adapted to the electrode terminal 30 with a complex structure. When subjected to external force (such as the clamping force applied to the first insulating member 40 by the first wall 211 and the first limiting part 32), the first insulating member 40 containing thermoplastic material can undergo a certain degree of deformation without easily breaking, and has good toughness and impact resistance, thus improving the insulation effect.

[0198] In some embodiments, the compressive modulus of the first insulating member 40 is less than that of the second insulating member 50.

[0199] As an example, the compression modulus of the first insulating member 40 can be measured with reference to GB / T 1041-2008 Determination of the compressive properties of plastics.

[0200] As an example, the material of the second insulating member 50 is plastic, such as polyimide, and the compressive modulus of the second insulating member 50 can be measured with reference to GB / T 1041-2008 Determination of compressive properties of plastics.

[0201] As an example, the material of the second insulating member 50 is ceramic, and the compressive modulus of the second insulating member 50 can be measured with reference to GB / T 1964-2023 Test Method for Room Temperature Compressive Strength of Porous Ceramics.

[0202] When the battery cell 7 is subjected to external impact, the second insulating member 50 may vibrate; the first insulating member 40 has a small compressive modulus, which can release stress through compression deformation when the second insulating member 50 vibrates, thereby reducing the risk of cracking of the second insulating member 50 and the risk of insulation failure.

[0203] In some embodiments, the first insulating member 40 includes a first insulating portion 41 and a second insulating portion 42 connected to each other. The second insulating portion 42 is disposed at one end of the first insulating member 40 near the terminal body 31, and the thickness of the second insulating portion 42 is less than the thickness of the first insulating portion 41.

[0204] Along the thickness direction Z of the first wall 211, at least a portion of the first insulating part 41 and the second insulating part 42 are disposed between the first limiting part 32 and the first wall 211, and at least a portion of the second insulating member 50 is disposed between the second insulating part 42 and the first limiting part 32.

[0205] For example, the second insulating portion 42 may extend circumferentially along the terminal body 31. For instance, the second insulating portion 42 may surround the terminal body 31; alternatively, the second insulating portion 42 may extend less than one circumference along the terminal body 31.

[0206] In the thickness direction Z of the first wall 211, the first insulating part 41 can be integrally disposed between the first limiting part 32 and the first wall 211, or it can be partially disposed between the first limiting part 32 and the first wall 211.

[0207] In the thickness direction Z, the second insulating member 50 can be integrally disposed between the first limiting part 32 and the second insulating part 42, or it can be partially disposed between the first limiting part 32 and the second insulating part 42.

[0208] The second insulating member 50 and the second insulating part 42 can be in contact, or they can be spaced apart in the thickness direction Z.

[0209] By providing the second insulating part 42, the space occupied by the first insulating member 40 and the second insulating member 50 in the thickness direction Z can be reduced, thereby improving space utilization. During thermal runaway of the battery cell 7, the internal pressure of the casing 20 increases, and the terminal body 31 may shift outward through the electrode lead-out hole 2111 under the influence of internal pressure. By placing the second insulating part 42 at the end of the first insulating member 40 near the terminal body 31, the second insulating member 50 can be positioned close to the terminal body 31, thereby constraining the terminal body 31, reducing the offset of the terminal body 31 under internal pressure, reducing the deformation of the first limiting part 32, lowering the risk of the first limiting part 32 contacting the first wall 211, and improving reliability.

[0210] The simultaneous provision of a first insulating component 40 and a second insulating component 50 allows for greater flexibility in the selection of materials for the first insulating component 40, which helps to optimize design and reduce costs.

[0211] In some embodiments, at least a portion of the first insulating portion 41 is sandwiched between the first wall 211 and the first limiting portion 32 in the thickness direction Z to fix the first insulating member 40 to the first wall 211.

[0212] In some embodiments, in the thickness direction Z of the first wall 211, the distance D between the second insulating portion 42 and the first limiting portion 32 is greater than the thickness T of the second insulating member 50.

[0213] In some examples, the second insulating member 50 is spaced apart from the second insulating portion 42 along the thickness direction Z of the first wall 211, and the second insulating member 50 is in contact with the first limiting portion 32; in other examples, the second insulating member 50 is in contact with the second insulating portion 42 along the thickness direction Z of the first wall 211, and the second insulating member 50 is spaced apart from the first limiting portion 32; in still other examples, both the second insulating portion 42 and the first limiting portion 32 are spaced apart from the second insulating member 50 along the thickness direction Z of the first wall 211.

[0214] The embodiments of this application can reduce the pressure on the second insulating member 50, reduce the risk of cracking of the second insulating member 50, and improve reliability.

[0215] In some embodiments, the second insulating member 50 is fixed to at least one of the first insulating member 40 and the first limiting portion 32.

[0216] For example, the second insulating member 50 can be fixed to at least one of the first insulating member 40 and the first limiting portion 32 by adhesive bonding.

[0217] When the battery cell 7 is subjected to external impact, the first insulating member 40 or the first limiting part 32 can constrain the second insulating member 50, reduce the vibration of the second insulating member 50, and reduce the risk of cracking or failure of the second insulating member 50.

[0218] In some embodiments, the second insulating member 50 is fixed to one of the first insulating member 40 and the first limiting portion 32, and is spaced apart from the other.

[0219] In some embodiments, the second insulating member 50 surrounds the terminal body 31, which can increase the insulation area and improve the insulation effect. In the event of thermal runaway of the battery cell 7, the second insulating member 50 surrounding the terminal body 31 helps to improve the uniformity of the force on the first limiting part 32, reduce the deformation of the first limiting part 32, reduce the risk of the first limiting part 32 contacting the first wall 211, and improve reliability.

[0220] In some embodiments, the second insulating portion 42 surrounds the terminal body 31, and the first insulating portion 41 surrounds the second insulating portion 42.

[0221] In some embodiments, the thickness T of the second insulating member 50 is 0.2 mm to 1.2 mm.

[0222] For example, T is 0.2mm, 0.3mm, 0.4mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1.0mm, 1.1mm or 1.2mm.

[0223] In this embodiment, the thickness of the second insulating member 50 is set to be greater than or equal to 0.2 mm to increase the distance between the first wall 211 and the first limiting part 32 in the event of thermal runaway of the battery cell 7, thereby reducing the risk of contact between the first limiting part 32 and the first wall 211. Setting the thickness of the second insulating member 50 to be less than or equal to 1.2 mm can save the space occupied by the second insulating member 50 and reduce the impact of setting the second insulating member 50 on the energy density of the battery cell 7.

[0224] In some embodiments, the battery cell 7 includes a seal 60 surrounding the terminal body 31. In the thickness direction Z, at least a portion of the seal 60 is clamped between the first limiting portion 32 and the first wall 211.

[0225] The first limiting part 32 and the first wall 211 can clamp the sealing member 60 in the thickness direction Z to achieve the sealing of the electrode lead-out hole 2111.

[0226] In some embodiments, the second insulating member 50 surrounds the seal 60. The seal 60 may radially limit the second insulating member 50, thereby reducing the radial vibration of the second insulating member 50 in the seal 60 when the battery cell 7 is subjected to external impact, and reducing the risk of cracking or failure of the second insulating member 50.

[0227] In some embodiments, the seal 60 contacts the second insulating member 50, and the contact surface between the seal 60 and the second insulating member 50 surrounds the terminal body 31.

[0228] The seal 60 can limit the second insulating member 50 in the radial direction, thereby fixing the second insulating member 50 in the radial direction and reducing the risk of the second insulating member 50 cracking or failing when the battery cell 7 is subjected to external impact.

[0229] In some embodiments, the second insulating member 50 is interference-fitted with the seal 60 in the radial direction of the seal 60, which helps to improve the stability of the contact between the second insulating member 50 and the seal 60 and reduces the risk of the second insulating member 50 cracking or failing when the battery cell 7 is subjected to external impact.

[0230] In some embodiments, the outer diameter of the seal 60 is d1, and the inner diameter of the second insulating member 50 is d2, where d1 ≥ d2. During assembly, the seal 60 and the second insulating member 50 are interference-fitted to fix the second insulating member 50 to the seal 60.

[0231] In some embodiments, the second insulating member 50 is interference-fitted with the seal 60 in the radial direction. Optionally, the second insulating member 50 may not be directly fixedly connected to the first limiting portion 32, or it may not be directly fixedly connected to the second insulating portion 42.

[0232] In some embodiments, the second insulating portion 42 surrounds the seal 60. A first gap G1 is provided between the seal 60 and the second insulating portion 42 in the radial direction of the seal 60.

[0233] By setting a first gap G1, the risk of overlap between the seal 60 and the second insulating part 42 in the thickness direction Z due to assembly errors can be reduced, thereby reducing the risk of interference between the seal 60 and the second insulating part 42 and improving reliability.

[0234] In some embodiments, the projection of the first gap G1 in the thickness direction Z at least partially overlaps with the projection of the second insulating member 50.

[0235] The second insulating member 50 can at least partially separate the first gap G1 from the first limiting part 32, thereby increasing the creepage distance between the first limiting part 32 and the first wall 211, reducing the risk of the first wall 211 and the first limiting part 32 becoming conductive, and improving reliability.

[0236] In some embodiments, the projection of the first gap G1 in the thickness direction Z lies within the projection of the second insulating member 50.

[0237] In some embodiments, a second insulating member 50 is disposed between the first insulating portion 41 and the sealing member 60 in the radial direction of the sealing member 60.

[0238] In some embodiments, the outer diameter of the second insulating member 50 is d3, and the inner diameter of the first insulating part 41 is d4, where d4 ≥ d3.

[0239] In some embodiments, a second gap G2 is provided between the second insulating member 50 and the first insulating portion 41.

[0240] By setting a second gap G2, the risk of the second insulating member 50 and the first insulating part 41 overlapping in the thickness direction Z due to assembly errors can be reduced, thereby reducing the risk of interference between the second insulating member 50 and the first insulating part 41 and improving reliability.

[0241] In some embodiments, d4 > d3 to form a second gap G2.

[0242] In some embodiments, the thermal weight loss temperature of the seal 60 is greater than or equal to 200°C. As an example, the thermal weight loss temperature of the seal 60 may be 200°C, 250°C, 300°C, 350°C, 400°C, 450°C, 500°C, 550°C, 600°C, 650°C, 700°C, 750°C, or 800°C.

[0243] For example, the thermogravimetric temperature of the seal 60 can be the 5% thermogravimetric temperature. The thermogravimetric temperature of the seal 60 can be measured with reference to GB / T27761-2011 Test Method for Weight Loss and Residual Weight by Thermogravimetric Analyzer.

[0244] The seal 60 is less likely to lose weight or lose less weight when the battery cell 7 experiences thermal runaway, thus enabling the seal 60 to remain between the first wall 211 and the electrode terminal 30, reducing the risk of direct contact between the electrode terminal 30 and the first wall 211.

[0245] In some embodiments, the seal 60 is electrically insulating. Exemplarily, the seal 60 is made of an insulating material. After thermal runaway of the battery cell 7, the seal 60 can suppress the current between the first limiting portion 32 and the first wall 211, reducing the continuous heat generation between the electrode terminals 30 and the first wall 211, lowering the risk of thermal runaway in other battery cells 7, and improving reliability.

[0246] In some embodiments, the thermal weight loss temperature of the seal 60 is lower than that of the second insulating member 50. To achieve a seal, the seal 60 is typically in a compressed state; even if the weight loss rate of the seal 60 is greater than that of the second insulating member 50 in the event of thermal runaway in the battery cell 7, it can still fill the space between the first limiting portion 32 and the first wall 211, reducing the risk of direct contact between the first limiting portion 32 and the first wall 211.

[0247] In some embodiments, the seal 60 comprises a thermosetting material. The seal 60 comprising a thermosetting material can maintain good stability at high temperatures and can isolate the first limiting portion 32 from the first wall 211 in the event of thermal runaway of the battery cell 7.

[0248] In some embodiments, the material of the seal 60 includes fluororubber. Optionally, the material of the seal 60 includes thermosetting fluororubber.

[0249] In some embodiments, the first wall 211 includes a wall body 2112 and a protrusion 2113, the protrusion 2113 protruding from the surface of the wall body 2112 toward the receiving cavity 20b, and an electrode lead-out hole 2111 is disposed on the protrusion 2113.

[0250] By providing the protrusion 2113, the strength of the portion of the first wall 211 around the electrode lead-out hole 2111 can be increased, and the deformation of the first wall 211 during the molding process of the battery cell 7 and during use can be reduced.

[0251] In some embodiments, in the thickness direction Z, at least a portion of the first insulating portion 41 is disposed between the first limiting portion 32 and the wall body 2112, at least a portion of the second insulating portion 42 is disposed between the first limiting portion 32 and the protrusion 2113, and the second insulating member 50 at least partially overlaps with the protrusion 2113.

[0252] When the second insulating part 42 fails due to thermal runaway of the battery cell 7, the second insulating member 50 can separate the protrusion 2113 from the first limiting part 32 to reduce the risk of the first limiting part 32 contacting the protrusion 2113. The protrusion 2113 protrudes from the wall body 2112. By providing the protrusion 2113, the distance between the wall body 2112 and the first limiting part 32 can be increased, thereby reducing the risk of the first wall 211 and the first limiting part 32 contacting due to deformation and improving reliability.

[0253] In some embodiments, the first insulating member 40 is provided with a first recess 43 and a second recess 44, and in the thickness direction Z, the first recess 43 and the second recess 44 are respectively provided on both sides of the second insulating portion 42. At least a portion of the second insulating member 50 is provided in the first recess 43, and at least a portion of the protrusion 2113 is provided in the second recess 44.

[0254] In the radial direction of the terminal body 31, the dimensions of the first recess 43 and the second recess 44 may be the same or different.

[0255] For example, the bottom surface of the first recess 43 and the bottom surface of the second recess 44 are disposed opposite each other along the thickness direction Z, and the portion of the first insulating member 40 located between the bottom surface of the first recess 43 and the bottom surface of the second recess 44 forms at least a portion of the second insulating portion 42.

[0256] In a projection plane perpendicular to the thickness direction Z, the orthographic projections of the side surface of the first recess 43 and the side surface of the second recess 44 may or may not overlap. Optionally, the side surface of the first recess 43 is a cylindrical surface, the side surface of the second recess 44 is a cylindrical surface, and the diameters of the side surfaces of the first recess 43 and the second recess 44 may be the same or different.

[0257] In this embodiment of the application, by providing the first recess 43 and the second recess 44, space can be provided for the protrusion 2113 and the second insulating member 50, thereby improving space utilization.

[0258] In some embodiments, the first recess 43 is annular and the second recess 44 is annular.

[0259] In some embodiments, the side surface of the first recess 43 extends beyond the side surface of the second recess 44 in the radial direction of the terminal body 31. In other words, in a projection plane perpendicular to the thickness direction Z, the orthographic projection of the side surface of the first recess 43 surrounds the outside of the orthographic projection of the side surface of the second recess 44.

[0260] In some embodiments, the first wall 211 is provided with a third recess 2114, which corresponds to the position of the protrusion 2113, and the third recess 2114 is recessed relative to the surface of the wall body 2112 away from the electrode assembly 10.

[0261] In some embodiments, the electrode terminal 30 further includes a second limiting portion 33, which is connected to the terminal body 31, and at least a portion of the second limiting portion 33 protrudes from the outer peripheral surface of the terminal body 31.

[0262] Along the thickness direction Z of the first wall 211, the first limiting part 32 and the second limiting part 33 are located on both sides of the first wall 211, respectively. The first limiting part 32 and the second limiting part 33 can fix the electrode terminal 30 along the thickness direction Z of the first wall 211.

[0263] In some examples, the first limiting part 32 and the terminal body 31 can be integrally formed. In other examples, the first limiting part 32 and the terminal body 31 are formed independently and connected by welding, riveting, bonding or other means.

[0264] In some embodiments, one of the first limiting portion 32 and the second limiting portion 33 is formed after the electrode terminal 30 passes through the electrode lead-out hole 2111.

[0265] In some examples, the electrode terminal 30 is riveted to the first wall 211 from the outside to form a second limiting portion 33. In other examples, the electrode terminal 30 is riveted to the first wall 211 from the inside to form a first limiting portion 32.

[0266] In some embodiments, the battery cell 7 further includes a third insulating member 70. In the thickness direction Z, at least a portion of the third insulating member 70 is disposed between the second limiting portion 33 and the first wall 211.

[0267] When the battery cell 7 is operating normally, the third insulating member 70 can separate the second limiting part 33 from the first wall 211 to reduce the risk of short circuit in the battery cell 7.

[0268] In some embodiments, a third insulating member 70 is disposed around the terminal body 31.

[0269] In some embodiments, the third insulating member 70 is made of plastic. For example, the third insulating member 70 is made of PFA (tetrafluoroethylene-perfluoroalkoxy vinyl ether copolymer).

[0270] In some embodiments, at least a portion of the third insulating member 70 is disposed in the third recess 2114.

[0271] In some embodiments, the housing 20 further includes a second wall 20a, with the first wall 211 and the second wall 20a located on opposite sides of the electrode assembly 10. The battery cell 7 includes a pressure relief mechanism 80 disposed on the second wall 20a.

[0272] As an example, the pressure relief mechanism 80 is actuated to release internal pressure or temperature when the internal pressure or temperature of the battery cell 7 reaches a predetermined threshold. When the internal pressure or temperature of the battery cell 7 reaches the predetermined threshold, the pressure relief mechanism 80 performs its action or a weak structure provided in the pressure relief mechanism 80 is destroyed, thereby forming an opening or channel for the release of internal pressure or temperature. The threshold design varies depending on design requirements. The threshold may depend on the materials of one or more of the positive electrode, negative electrode, electrolyte, and separator in the battery cell 7.

[0273] The term "actuation" as used in this application refers to the activation or actuation of the pressure relief mechanism to a certain state, thereby releasing the internal pressure and temperature of the battery cell. The actions of the pressure relief mechanism may include, but are not limited to: movement of components within the mechanism to form an exhaust channel, rupture, breakage, tearing, or opening of at least a portion of the mechanism, etc. When the pressure relief mechanism is activated, the high-temperature, high-pressure substances inside the battery cell are discharged as waste from the activated portion. This method allows for pressure and temperature relief of the battery cell under controllable pressure or temperature, thereby preventing potentially more serious accidents.

[0274] In the event of thermal runaway in a battery cell, the pressure relief mechanism can release the internal temperature and pressure of the battery cell, thereby reducing the risk of battery cell explosion.

[0275] In some examples, the pressure relief mechanism 80 and the second wall 20a are separately formed components, which can be connected by welding, bonding or other means. In other embodiments, the pressure relief mechanism 80 and the second wall 20a are integrally formed components; in other words, the pressure relief mechanism 80 may form part of the second wall 20a.

[0276] In this embodiment, the electrode terminal 30 and the pressure relief mechanism 80 are respectively disposed on both sides of the electrode assembly 10. This can reduce the impact on the first insulating member 40 and the second insulating member 50 during the release of high-temperature gas, thereby reducing the risk of failure of the first insulating member 40 and the second insulating member 50.

[0277] During the release of high-temperature gas, some of the heat will be conducted to the second wall 20a. The second wall 20a is farther away from the first wall 211, which can reduce the heat conducted to the first wall 211 and to the first insulating member 40 and the second insulating member 50, thereby reducing the thermal weight loss of the first insulating member 40 and the second insulating member 50, improving the insulation effect, and increasing the reliability of the battery cell 7.

[0278] By placing the pressure relief mechanism 80 on the second wall 20a, the high-temperature particles sputtered near the electrode terminal 30 can be reduced, thereby reducing the risk of insulation failure between the first wall 211 and the electrode terminal 30.

[0279] In some embodiments, the pressure relief mechanism 80 includes a pressure relief portion 81 and a weak portion 82 disposed along the outer periphery of the pressure relief portion 81.

[0280] The weak point 82 is a relatively weak part of the pressure relief mechanism 80, which is a part of the pressure relief mechanism 80 that is prone to breakage, fracture, tearing, or opening. For example, the strength of the pressure relief mechanism 80 is less than the strength of the portion of the pressure relief mechanism 80 near the weak point 82.

[0281] In some examples, this application may create grooves, notches, through holes, or other structures in a predetermined area of ​​the pressure relief mechanism 80 to reduce the local strength of the pressure relief mechanism 80, thereby forming a weak portion 82 in the pressure relief mechanism 80. For example, a thinning process may be performed on a predetermined area of ​​the pressure relief mechanism 80, and the thinned portion of the pressure relief mechanism 80 forms the weak portion 82. In other examples, a material treatment may be performed on a predetermined area of ​​the pressure relief mechanism 80 so that the strength of this area is weaker than the strength of other areas; in other words, this area is the weak portion 82.

[0282] The weak part 82 can rupture when the internal pressure or temperature of the battery cell 7 reaches a threshold; the pressure relief part 81 can be the part of the pressure relief mechanism 80 used to form a pressure relief channel when the weak part 82 ruptures.

[0283] In some examples, the weak portion 82 may surround the pressure relief portion 81. In the event of thermal runaway of the battery cell 7, the weak portion 82 ruptures at least partially; for example, the weak portion 82 ruptures completely, and the pressure relief portion 81 detaches from the casing 20, thereby forming a pressure relief channel; for example, the weak portion 82 ruptures partially, and the pressure relief portion 81 flips outward under the internal pressure of the battery cell 7 to form a pressure relief channel.

[0284] In other examples, the weak portion 82 may also partially surround the pressure relief portion 81. The line connecting the two ends of the weak portion 82 and the weak portion 82 together define the pressure relief portion 81. In the event of thermal runaway of the battery cell 7, the weak portion 82 ruptures, and the pressure relief portion 81 can be rotated outward about the line connecting the two ends of the weak portion 82 under the action of the internal pressure of the battery cell 7 to form a pressure relief channel.

[0285] In some embodiments, the pressure relief mechanism 80 is integrally formed with the second wall 20a. Exemplarily, the second wall 20a is provided with a fourth recess 83, and the weak portion 82 includes the bottom wall of the fourth recess 83. The fourth recess 83 is disposed around the pressure relief portion 81.

[0286] In some embodiments, the battery cell 7 is a cylindrical battery cell. Cylindrical battery cells have advantages such as mature manufacturing processes, good consistency, good heat dissipation performance, and high assembly efficiency. Exemplarily, the first wall 211 and the second wall 20a are arranged opposite each other along the axial direction of the cylindrical battery cell. The pressure relief mechanism 80 includes a pressure relief portion 81 and a weak portion 82 arranged along the outer periphery of the pressure relief portion 81, and the pressure relief portion 81 is circular.

[0287] In some embodiments, the battery cell 7 is a cylindrical battery cell with a diameter greater than or equal to 35 mm and less than or equal to 70 mm.

[0288] As an example, the diameter of the cylindrical battery cell is 35mm, 40mm, 45mm, 50mm, 55mm, 60mm, 65mm or 70mm.

[0289] Setting the diameter of the cylindrical battery cell to be greater than or equal to 35 mm can improve the capacity and energy density of the cylindrical battery cell. The diameter of the cylindrical battery cell is related to the heat generation during thermal runaway. Setting the diameter of the cylindrical battery cell to be less than or equal to 70 mm can limit the maximum temperature of the cylindrical battery cell during thermal runaway and reduce the risk of simultaneous failure of the first insulating component 40 and the second insulating component 50.

[0290] In some embodiments, the height of the housing 20 is from 50 mm to 150 mm. For example, the height of the housing 20 is 50 mm, 55 mm, 60 mm, 65 mm, 70 mm, 75 mm, 80 mm, 85 mm, 90 mm, 95 mm, 100 mm, 105 mm, 110 mm, 115 mm, 120 mm, 125 mm, 130 mm, 135 mm, 140 mm, 145 mm, or 150 mm. Optionally, the height of the housing 20 is 60 mm to 100 mm.

[0291] In some embodiments, the height of the housing 20 is 1.3 to 4 times the diameter of the housing 20. Exemplarily, the height of the housing 20 may be the dimension of the housing 20 along the axial direction of the cylindrical battery cell.

[0292] Optionally, the height of the outer casing 20 is 1.3 times, 1.4 times, 1.5 times, 1.6 times, 1.7 times, 1.8 times, 1.9 times, 2.0 times, 2.1 times, 2.2 times, 2.3 times, 2.4 times, 2.5 times, 2.6 times, 2.7 times, 2.8 times, 2.9 times, 3.0 times, 3.1 times, 3.2 times, 3.3 times, 3.4 times, 3.5 times, 3.6 times, 3.7 times, 3.8 times, 3.9 times, or 4.0 times the diameter of the outer casing 20.

[0293] When the housing 20 meets the above-mentioned dimensional requirements, the structural stability of the housing 20 is high, which can improve the reliability of the cylindrical battery cell.

[0294] In some embodiments, the height of the housing 20 is 1.5 to 2.5 times the diameter of the housing 20.

[0295] In some embodiments, the first wall 211 and the second wall 20a are located on opposite sides of the electrode assembly 10. The housing 20 also includes a side wall 212. The side wall 212 surrounds the electrode assembly 10 and connects the first wall 211 and the second wall 20a.

[0296] In some examples, the sidewall 212 and the first wall 211 may be integrally formed. In other examples, the sidewall 212 and the first wall 211 may also be formed independently and joined together by bonding, snap-fitting, welding or other means.

[0297] In some examples, the sidewall 212 and the second wall 20a may be integrally formed. In other examples, the sidewall 212 and the second wall 20a may also be formed independently and joined together by bonding, snap-fitting, welding or other means.

[0298] In some examples, the battery cell 7 is a cylindrical battery cell, and the side wall 212 may be a cylindrical structure. In other examples, the battery cell 7 is a prismatic battery cell, and the side wall 212 may be a prismatic structure.

[0299] In some embodiments, the housing 20 includes a housing 21 and an end cap 22. The housing 21 includes an integrally formed first wall 211 and a side wall 212. The end cap 22 is a second wall 20a and is sealed to the side wall 212.

[0300] The end cap 22 can be insulated from the side wall 212 or electrically connected.

[0301] The end of the housing 21 away from the first wall 211 has an opening, and the end cap 22 covers the opening of the housing 21.

[0302] The first wall 211 and the side wall 212 are integrally formed, and the connection strength between the first wall 211 and the side wall 212 is high. When the battery cell 7 is thermally runaway, the side wall 212 can bind the first wall 211, reduce the deformation of the first wall 211, reduce the risk of the first wall 211 being connected to the electrode terminal 30, improve the insulation effect, and improve the reliability of the battery cell 7.

[0303] In some embodiments, the sidewall 212 is made of steel.

[0304] In some embodiments, the thickness of the sidewall 212 is 0.3 mm to 1.5 mm.

[0305] As an example, the thickness of the sidewall 212 is 0.3mm, 0.31mm, 0.32mm, 0.33mm, 0.35mm, 0.38mm, 0.40mm, 0.42mm, 0.45mm, 0.5mm, 0.55mm, 0.6mm, 0.65mm, 0.7mm, 0.75mm, 0.8mm, 0.85mm, 0.9mm, 0.95mm, 1mm, 1.05mm, 1.1mm, 1.15mm, 1.2mm, 1.3mm, 1.35mm, 1.4mm, 1.45mm, or 1.5mm.

[0306] In the embodiments of this application, the thickness of the sidewall 212 has a meaning known in the art and can be detected using equipment and methods known in the art, such as a micrometer or vernier caliper.

[0307] As an example, the material of sidewall 212 includes stainless steel.

[0308] In some embodiments, the thickness of the sidewall 212 is 0.3 mm to 1.2 mm.

[0309] In some embodiments, the thickness of the sidewall 212 is 0.3 mm to 0.9 mm, optionally 0.3 mm to 0.6 mm.

[0310] In some embodiments, the material of the first wall 211 is the same as the material of the side wall 212.

[0311] In some embodiments, the end cap 22 is made of steel.

[0312] In some embodiments, the electrode assembly 10 has a first through hole 10d at its center.

[0313] In some examples, the electrode assembly 10 is a wound structure, and the first through hole 10d is formed at the winding center of the electrode assembly 10.

[0314] In some embodiments, the first through hole 10d is disposed between the electrode terminal 30 and the pressure relief mechanism 80 along the extending direction of the first through hole 10d.

[0315] When the battery cell 7 experiences thermal runaway, the gas between the electrode assembly 10 and the first wall 211 can flow to the pressure relief mechanism 80 through the first through hole 10d, thereby reducing the pressure on the first wall 211 and the electrode terminal 30, reducing the deformation of the first wall 211, and reducing the risk of short circuit.

[0316] In some embodiments, the extension direction of the first through hole 10d is parallel to the thickness direction Z of the first wall 211.

[0317] In some embodiments, a first tab 10a is disposed at one end of the electrode assembly 10 facing the first wall 211, and a second tab 10b is disposed at one end of the electrode assembly 10 facing the second wall 20a. The first tab 10a and the second tab 10b are respectively disposed at opposite ends of the electrode assembly 10, which can reduce the risk of the first tab 10a and the second tab 10b coming into contact.

[0318] In other embodiments, both the first tab 10a and the second tab 10b are disposed at the end of the electrode assembly 10 facing the first wall 211. The second tab 10b can be directly connected to the first wall 211, or it can be indirectly connected to the first wall 211 through other conductive structures.

[0319] In some embodiments, the battery cell 7 further includes a first current collector 91, which is connected to the first tab 10a and the electrode terminal 30.

[0320] In some embodiments, the first current collector 91 is located on the side of the first tab 10a facing the first wall 211 and is connected to the first tab 10a. The electrode terminal 30 abuts against and is connected to the surface of the first current collector 91 facing the first wall 211.

[0321] The first current collector 91 can act as a converter to realize the electrical connection between the first tab 10a and the electrode terminal 30.

[0322] In some embodiments, the electrode terminal 30 is provided with a terminal recess 34. The bottom wall of the terminal recess 34 is welded to the first current collector 91.

[0323] The terminal recess 34 can be provided on the side of the electrode terminal 30 facing the first current collector 91, or it can be provided on the side of the electrode terminal 30 away from the first current collector 91.

[0324] By providing the terminal recess 34, the thickness of the bottom wall of the terminal recess 34 can be reduced, the power required to weld the electrode terminal 30 to the first current collector 91 from the outside can be reduced, the risk of welding particles falling into the casing 20 can be reduced, and the reliability of the battery cell 7 can be improved.

[0325] In some embodiments, the electrode terminal 30 has a terminal recess 34 on the side opposite to the first current collector 91.

[0326] In some embodiments, the electrode terminal 30 has a terminal recess 34 on the side facing the first current collector 91, and another terminal recess 34 on the side of the electrode terminal 30 away from the first current collector 91; the corresponding portions of the bottom surfaces of the two terminal recesses 34 are welded to the first current collector 91.

[0327] In some embodiments, the bottom wall of the terminal recess 34 is provided with a second through hole 311, which can be used to inject electrolyte.

[0328] In some embodiments, the battery cell 7 further includes a cover plate 92, which is connected to the electrode terminal 30 and serves to separate the second through hole 311 from the external space of the battery cell 7.

[0329] In some embodiments, at least a portion of the cover plate 92 is accommodated in the terminal recess 34.

[0330] In some embodiments, the battery cell 7 further includes a sealing pin 93, which is inserted into the second through hole 311 and seals the second through hole 311.

[0331] In some embodiments, the first electrode tab 10a is a positive electrode tab 1111, and the positive electrode lead-out portion includes a cover plate 92 and an electrode terminal 30; alternatively, the first electrode tab 10a is a negative electrode tab 1211, and the negative electrode lead-out portion includes a cover plate 92 and an electrode terminal 30.

[0332] In some embodiments, a terminal recess 34 is formed on the terminal body 31.

[0333] In some embodiments, the battery cell 7 further includes a second current collector 94, a second tab 10b connected to the second current collector 94, and at least one of the sidewall 212 and the second wall 20a connected to the second current collector 94, so that the sidewall 212 is electrically connected to the first wall 211 and the second current collector 94.

[0334] In some examples, the second current collector 94 is connected to the second wall 20a, which is electrically connected to the side wall 212. The second tab 10b is electrically connected to the first wall 211 via the second current collector 94, the second wall 20a, and the side wall 212.

[0335] In other examples, the second current collector 94 is connected to the sidewall 212. The second tab 10b is electrically connected to the first wall 211 via the second current collector 94 and the sidewall 212. Optionally, the second wall 20a is insulated from the sidewall 212.

[0336] In some embodiments, the second current collector 94 is connected to the second wall 20a. Optionally, the second wall 20a is welded to the side wall 212.

[0337] Figure 14 This is a partial cross-sectional schematic diagram of a battery cell provided for other embodiments of this application.

[0338] Reference Figure 14 In some embodiments, the sidewall 212 is provided with an inwardly protruding sidewall protrusion 2121. In the thickness direction Z of the first wall 211, at least a portion of the sidewall protrusion 2121 is located between the end cap 22 and the second tab 10b.

[0339] For example, the sidewall protrusion 2121 can be a solid structure or a hollow structure.

[0340] The side wall protrusion 2121 overlaps with the second tab 10b in the thickness direction Z. When the battery cell 7 is subjected to external impact, it can restrict the movement of the second tab 10b in the thickness direction Z and reduce the risk of failure of the connection between the second tab 10b and the second current collector 94.

[0341] In some embodiments, the second current collector 94 is connected to the sidewall protrusion 2121. As an example, the second current collector 94 may be welded to the sidewall protrusion 2121; alternatively, the second current collector 94 may also be press-fitted to the sidewall protrusion 2121.

[0342] For example, the second current collector 94 is connected to the side of the sidewall protrusion 2121 facing the second electrode 10b, or it can be connected to the side of the sidewall protrusion 2121 facing the end cap 22.

[0343] Connecting the second current collector 94 to the side wall protrusion 2121 can shorten the conductive path between the second tab 10b and the first wall 211, reduce resistance, reduce heat generation, and improve the cycle performance of the battery cell 7.

[0344] In some embodiments, a portion of the second manifold member 94 is located on the side of the sidewall protrusion 2121 facing the end cap 22 and is connected to the sidewall protrusion 2121. The second manifold member 94 is connected to the sidewall protrusion 2121 from the outside of the sidewall protrusion 2121, which can reduce assembly difficulty.

[0345] In some embodiments, the second current collector 94 is welded to the sidewall protrusion 2121.

[0346] In some embodiments, the sidewall 212 has a sidewall recess 2122 on its outer side, which corresponds to the sidewall protrusion 2121. As an example, after the electrode assembly 10 is installed into the housing 21, the sidewall 212 is pressed from the outside to form an inwardly protruding sidewall protrusion 2121.

[0347] In some embodiments, the sidewall 212 further includes a crimping portion 2123, which extends from the end of the sidewall protrusion 2121 away from the first wall 211 and surrounds the end cap 22.

[0348] A portion of the crimping part 2123 is bent to form a flange structure, and a portion of the end cap 22 is located between the flange structure and the side wall protrusion 2121 in the thickness direction Z. The side wall protrusion 2121 and the flange structure can limit the end cap 22 to fix the end cap 22 in the thickness direction Z.

[0349] In some embodiments, the battery cell 7 further includes a fourth insulating member 95, which is disposed between the sidewall 212 and the end cap 22 and insulates the end cap 22 from the sidewall 212.

[0350] In some embodiments, a portion of the fourth insulating member 95 is located between the second current collector 94 and the end cap 22 to insulate the second current collector 94 from the end cap 22.

[0351] Figure 15 Explosion-proof diagrams of individual battery cells provided in other embodiments of this application; Figure 16 This is a partial cross-sectional schematic diagram of a battery cell provided for other embodiments of this application.

[0352] Reference Figure 15 and Figure 16 In some embodiments, the battery cell 7 is a square-shell battery cell. Exemplarily, the sidewall 212 is a square tube.

[0353] In some embodiments, the housing 20 includes a housing 21 and an end cap 22. The housing 21 includes an integrally formed second wall 20a and a side wall 212. The end cap 22 is a first wall 211 and is sealed to the side wall 212.

[0354] In some embodiments, the first limiting part 32 is integrally formed with the terminal body 31, and the second limiting part 33 is riveted to the terminal body 31.

[0355] In some embodiments, the battery cell 7 may include an electrode lead-out portion 90 disposed on the end cap 22, the electrode lead-out portion 90 being electrically connected to the second tab 10b and the end cap 22. The electrode lead-out portion 90 and the electrode terminal 30 may serve as two electrodes of the battery cell 7.

[0356] In some embodiments, the second tab 10b can be a positive tab 1111, and the end cap 22 can be made of aluminum or aluminum alloy. Electrically connecting the second tab 10b to the end cap 22 can keep the end cap 22 at a high potential, reducing the risk of the end cap 22 being corroded by the electrolyte.

[0357] In other embodiments, the second tab 10b may be the negative tab 1211, and the end cap 22 may be made of steel.

[0358] Figure 17 This is a simplified schematic diagram of a battery device provided for other embodiments of this application.

[0359] Reference Figure 17 This application also provides a battery device 2, which includes a plurality of battery cells 7 according to any of the above embodiments.

[0360] In some embodiments, the battery device 2 further includes a plurality of busbars 8 that electrically connect a plurality of battery cells 7.

[0361] In some embodiments, at least two battery cells 7 are connected in parallel.

[0362] For example, at least two battery cells 7 are connected in parallel to form a battery cell 7a, and multiple battery cells 7a are connected in series. The multiple battery cells 7 of the battery device 2 form a multi-parallel series structure. The multi-parallel series structure can improve reliability. If a battery cell 7 fails due to an accident (such as thermal runaway), the battery cells 7 connected in parallel with that battery cell 7 can still operate normally, reducing the risk of complete circuit failure.

[0363] When a battery cell 7 experiences thermal runaway, normal battery cells 7 connected in parallel with the thermally runaway battery cell 7 may be electrically connected to the first wall 211 and the electrode terminal 30 of the thermally runaway battery cell 7, respectively. The second insulating member 50 can suppress the current between the electrode terminal 30 and the first wall 211, reduce the continuous heat generation between the electrode terminal 30 and the first wall 211, reduce the thermal impact on other battery cells 7 in the vicinity, reduce the risk of thermal runaway in other battery cells 7, and improve reliability.

[0364] According to some embodiments of this application, this application also provides an electrical device, including a battery cell 7 of any of the above embodiments, wherein the battery cell 7 is used to provide electrical energy to the electrical device. The electrical device can be any of the aforementioned devices or systems that utilize the battery cell 7.

[0365] Reference Figures 4 to 13 This application provides a cylindrical battery cell, which includes a housing 20, electrode terminals 30, electrode assembly 10, a first insulating member 40, a second insulating member 50, a third insulating member 70, and a sealing member 60.

[0366] The housing 20 includes a housing 21 and an end cap 22. The housing 21 includes an integrally formed side wall 212 and a first wall 211. The side wall 212 surrounds the electrode assembly 10. The first wall 211 and the end cap 22 are opposite to each other, and the end cap 22 is sealed to the side wall 212.

[0367] The electrode assembly 10 is housed within the housing 20. The electrode assembly 10 includes a first tab 10a and a second tab 10b, the first tab 10a being electrically connected to the electrode terminal 30, and the second tab 10b being electrically connected to the first wall 211.

[0368] The first wall 211 is provided with an electrode lead-out hole 2111. The electrode terminal 30 includes a terminal body 31, a first limiting portion 32, and a second limiting portion 33. At least a portion of the terminal body 31 is accommodated in the electrode lead-out hole 2111. The first limiting portion 32 is connected to the terminal body 31, and at least a portion of the first limiting portion 32 protrudes from the outer peripheral surface of the terminal body 31. The second limiting portion 33 is connected to the terminal body 31, and at least a portion of the second limiting portion 33 protrudes from the outer peripheral surface of the terminal body 31. In the thickness direction Z of the first wall 211, the first limiting portion 32 is located inside the first wall 211, and the second limiting portion 33 is located outside the first wall 211.

[0369] The first insulating member 40 includes a first insulating portion 41 and a second insulating portion 42 connected to each other. The second insulating portion 42 is disposed at one end of the first insulating member 40 near the terminal body 31 and surrounds the terminal body 31. The first insulating portion 41 surrounds the second insulating portion 42. The thickness of the second insulating portion 42 is less than the thickness of the first insulating portion 41.

[0370] In the thickness direction Z of the first wall 211, at least a portion of the first insulating portion 41 is sandwiched between the first wall 211 and the first limiting portion 32, and the second insulating portion 42 is disposed between the first limiting portion 32 and the first wall 211. In the thickness direction Z, at least a portion of the second insulating member 50 is disposed between the second insulating portion 42 and the first limiting portion 32.

[0371] The thermal weight loss temperature of the second insulating member 50 is greater than that of the first insulating member 40. The melting point of the second insulating member 50 is higher than that of the first insulating member 40.

[0372] A seal 60 surrounds the terminal body 31. In the thickness direction Z, at least a portion of the seal 60 is clamped between the first limiting portion 32 and the first wall 211. A second insulating member 50 surrounds the seal 60.

[0373] In the thickness direction Z, at least a portion of the third insulating member 70 is disposed between the second limiting portion 33 and the first wall 211.

[0374] Although this application has been described with reference to preferred embodiments, various modifications can be made thereto and components can be replaced with equivalents without departing from the scope of this application. In particular, the technical features mentioned in the various embodiments can be combined in any manner, provided there is no structural conflict. This 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, characterized by, The battery cell includes: a housing including a first wall and a housing cavity, the first wall being provided with an electrode lead-out hole communicating with the housing cavity; an electrode terminal including a terminal body and a first limiting portion connected to each other, at least a portion of the terminal body being housed in the electrode lead-out hole, at least a portion of the first limiting portion protruding from an outer peripheral surface of the terminal body and being located on a side of the first wall facing the housing cavity; an electrode assembly housed in the housing cavity, the electrode assembly including first and second tabs having opposite polarities, the first tab being electrically connected to the electrode terminal, and the second tab being electrically connected to the first wall; a first insulating member disposed around the terminal body, at least a portion of the first insulating member being disposed between the first limiting portion and the first wall in a thickness direction of the first wall; a second insulating member, at least a portion of the second insulating member being disposed between the first insulating member and the first limiting portion in the thickness direction, the second insulating member having a thermal weight loss temperature greater than a thermal weight loss temperature of the first insulating member.

2. The battery cell of claim 1, wherein, The thermal weight loss temperature of the second insulating member is greater than or equal to 300°C.

3. The battery cell of claim 1, wherein, The melting point of the second insulating member is higher than the melting point of the first insulating member.

4. The battery cell of claim 1, wherein, The compression modulus of the first insulating member is less than the compression modulus of the second insulating member.

5. The battery cell of any one of claims 1-4, wherein, The first insulating member includes a first insulating portion and a second insulating portion connected to each other, the second insulating portion being disposed at an end of the first insulating member close to the terminal body, the second insulating portion having a thickness less than a thickness of the first insulating portion; in the thickness direction of the first wall, at least a portion of the first insulating portion and the second insulating portion are disposed between the first limiting portion and the first wall, and at least a portion of the second insulating member is disposed between the second insulating portion and the first limiting portion.

6. The battery cell of claim 5, wherein, In the thickness direction of the first wall, a distance between the second insulating portion and the first limiting portion is greater than the thickness of the second insulating member.

7. The battery cell of claim 5, wherein, The battery cell includes a seal member surrounding the terminal body; in the thickness direction, at least a portion of the seal member is clamped between the first limiting portion and the first wall; the second insulating member surrounds the seal member.

8. The battery cell of claim 7, wherein, The seal member is in contact with the second insulating member, and a contact surface between the seal member and the second insulating member surrounds the terminal body.

9. The battery cell of claim 7, wherein, The second insulating portion surrounds the seal member; in a radial direction of the seal member, a first gap is provided between the seal member and the second insulating portion; in the thickness direction, a projection of the first gap at least partially overlaps a projection of the second insulating member.

10. The battery cell of claim 7, wherein, In the radial direction of the seal member, the second insulating member is disposed between the first insulating portion and the seal member, and a second gap is provided between the second insulating member and the first insulating portion.

11. The battery cell of claim 5, wherein, The first wall includes a wall body and a protruding portion protruding from a surface of the wall body toward the housing cavity, and the electrode lead-out hole is provided in the protruding portion; In the thickness direction, at least part of the first insulating portion is arranged between the first limiting portion and the wall body, and at least part of the second insulating portion is arranged between the first limiting portion and the convex portion, and the second insulating member at least partially overlaps the convex portion.

12. The battery cell of claim 11, wherein, The first insulating member is provided with a first recess and a second recess, and in the thickness direction, the first recess and the second recess are respectively arranged on both sides of the second insulating portion. At least part of the second insulating member is arranged in the first recess, and at least part of the convex portion is arranged in the second recess.

13. The battery cell of claim 1, wherein, The second insulating member is fixed to at least one of the first insulating member and the first limiting portion.

14. The battery cell of claim 1, wherein, The second insulating member surrounds the terminal body.

15. The battery cell of claim 1, wherein, The material of the second insulating member is polyimide or ceramic.

16. The battery cell of claim 1, wherein, The thickness of the second insulating member is 0.2mm-1.2mm.

17. The battery cell of claim 1, wherein, The shell further comprises a second wall, and the first wall and the second wall are respectively arranged on both sides of the electrode assembly. The battery cell comprises a pressure relief mechanism arranged on the second wall.

18. The battery cell of claim 1, wherein, The battery cell is a cylindrical battery cell, and the diameter of the cylindrical battery cell is greater than or equal to 35mm and less than or equal to 70mm.

19. A battery device characterized by comprising: The battery device comprises a plurality of battery cells according to any one of claims 1-18.

20. The battery device of claim 19, wherein, At least two of the battery cells are connected in parallel.

21. An electrical device, comprising: The battery device according to claim 19 or 20 is used to provide electric energy.

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