Battery cell, battery device, and electric device

Abstract

Provided in the present application are a battery cell, a battery device, and an electric device. The battery cell (300) comprises a housing (32) and an electrode assembly (31). A channel (301) is provided between a main portion (311) of the electrode assembly (31) and a peripheral sidewall (3202) of the housing (32). A pressure relief mechanism (35) is provided on the peripheral sidewall (3202), and the pressure relief mechanism (35) comprises a pressure relief portion (351) in communication with the channel (301). The shortest path from any position of the channel (301) to the pressure relief portion (351) in an extension direction of the channel (301) is less than or equal to 550 mm. The shortest path for gas generated by thermal runaway at any position on the electrode assembly to discharge into the channel, and reach the pressure relief portion via the channel for pressure relief is less than or equal to 550 mm, thereby facilitating the discharge of gas generated by thermal runaway so as to ensure smooth gas discharge and to improve the safety of the battery cell.

Description

Battery cells, battery packs and electrical devices Technical Field

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

[0002] Energy conservation and emission reduction are key to the sustainable development of the automotive industry, and electric vehicles, due to their energy-saving and environmentally friendly advantages, have become an important component of this sustainable development. For electric vehicles, battery technology is a crucial factor in their development.

[0003] When a battery cell experiences thermal runaway, the generated gas typically flows along the periphery of the cell to the pressure relief mechanism for release. However, to achieve high volumetric energy density, battery cells are often designed to be quite long, with tabs at the ends along the length, such as blade batteries where the length is much greater than the width and thickness. This results in an excessively long venting path for these cells, making them prone to poor venting during thermal runaway.

[0004] Application content

[0005] The purpose of this application is to provide a battery cell, a battery device, and an electrical device to improve the problem of poor exhaust of thermal runaway in battery cells with tabs at the ends in the related art.

[0006] In a first aspect, embodiments of this application provide a single battery cell, comprising:

[0007] The outer shell has a length direction, a width direction and a thickness direction. The length of the outer shell is greater than or equal to the width of the outer shell, and the width of the outer shell is greater than or equal to the thickness of the outer shell. The outer shell includes two first sidewalls located at opposite ends in the thickness direction and a peripheral sidewall connected between the two first sidewalls. The peripheral sidewall is connected to the two first sidewalls on both sides along the thickness direction.

[0008] An electrode assembly is disposed in a housing. The electrode assembly includes a main body, an electrode tab at one end of the main body along the length direction, and a channel between the main body and the peripheral sidewall.

[0009] The side wall is provided with a pressure relief mechanism, which includes a pressure relief part that is connected to the channel. The shortest path from any position in the channel along the extension direction of the channel to the pressure relief part is less than or equal to 550 mm.

[0010] In the technical solution of this application embodiment, by setting a channel between the peripheral sidewall and the main body of the electrode assembly, and making the shortest path from any position on the channel along the channel extension direction to the pressure relief part less than or equal to 550mm, the gas generated by thermal runaway at any position on the electrode assembly is discharged to the channel, and the minimum path from the channel to the pressure relief part is less than or equal to 550mm, thereby facilitating the discharge of gas generated by thermal runaway, so as to ensure smooth exhaust and improve the safety of the battery cell.

[0011] In some embodiments, the peripheral sidewall includes two second sidewalls located at opposite ends in the width direction, the distance between the two second sidewalls is W1, and the dimension of the electrode assembly in the width direction is W2, 0.01mm≤W1-W2≤8.75mm.

[0012] The above structure allows for a larger width at both ends of the channel in the width direction of the electrode assembly, enabling better venting in the event of thermal runaway and improving the safety of the battery cell.

[0013] In some embodiments, the channel includes sub-channels extending along the length direction, the sub-channels having a cross-sectional area S perpendicular to the length direction, the battery cell having a capacity C, and 0.05 mm². 2 / Ah≤S / C≤0.7mm 2 / Ah.

[0014] The above structural design allows the sub-channels to expel gases generated by thermal runaway of the electrode assembly more quickly and effectively, thus improving the safety of the battery cells.

[0015] In some embodiments, the subchannel has a first dimension L01 along the thickness direction and a second dimension L02 along the width direction, S = L01 * L02, the dimension of L01 ranges from 15mm to 80mm, and the dimension of L02 ranges from 1mm to 10mm.

[0016] Setting the first dimension L01 of the sub-channel along the thickness direction to 15mm-80mm and the second dimension L02 of the sub-channel along the width direction to 1mm-10mm can give the battery cell a higher volumetric energy density and can effectively balance the energy density of the battery cell with the cross-sectional area of ​​the sub-channel, so that in the event of thermal runaway, the generated gas can flow smoothly from the sub-channel to the pressure relief section.

[0017] In some embodiments, the capacity C of a single battery cell ranges from 5Ah to 250Ah.

[0018] Setting the capacity of a single battery cell to 5Ah-250Ah allows the gas generated by thermal runaway of the battery cell to flow smoothly from the channel to the pressure relief section for discharge.

[0019] In some embodiments, the housing includes a housing and an end cap, wherein the end of the housing in the longitudinal direction has an opening and the end cap covers the opening.

[0020] An opening is provided at the end of the housing along its length to facilitate the assembly of the electrode assembly and to facilitate the lead-out of the electrode assembly's tabs; an end cap is provided to cover the opening to seal the housing and protect the electrode assembly.

[0021] In some embodiments, the inner surface of the end cap is provided with a spacer for abutting the end face of the main body, and the spacer has a vent hole along the width direction.

[0022] By setting an isolator on the end cap, the distance between the main body and the end cap can be limited so that the upper electrode tab of the main body can be placed. The isolator is provided with a vent hole, which can serve as a channel to effectively discharge the generated gas in the event of thermal runaway of the electrode assembly, thereby improving the safety of the battery cell.

[0023] In some embodiments, the pressure resistance of the connection between the end cap and the housing ranges from 0.5 MPa to 5 MPa.

[0024] The above structure enables the battery cell to have good structural strength and airtightness.

[0025] In some embodiments, the channel includes a sub-channel extending along its length and communicating with a vent.

[0026] Ventilation holes are provided on the isolation component and connected to the sub-channels of the channel to form a channel between the main body and the peripheral sidewall, so that the gas generated by thermal runaway can flow to the pressure relief section for discharge.

[0027] In some embodiments, the cross-sectional area of ​​the vent along the width direction is greater than or equal to the cross-sectional area of ​​the sub-channel along the length direction.

[0028] Setting the cross-sectional area of ​​the vent to be greater than or equal to that of the sub-channel reduces the flow resistance of gas in the vent, allowing for better gas discharge in the event of thermal runaway of the electrode assembly and improving the safety of the battery cell.

[0029] In some embodiments, the housing is an aluminum housing, a steel housing, or a titanium housing.

[0030] The outer shell can be made of aluminum, which is lightweight and low-cost. A steel outer shell offers high structural strength and is also low-cost. A titanium outer shell provides high structural strength and good corrosion resistance.

[0031] In some embodiments, the perimeter of the outer shell is K, K = 2*(L+W), and 320mm≤K≤1100mm, where L is the length of the outer shell and W is the width of the outer shell.

[0032] Setting the perimeter of the casing to a range of 320mm-1100mm allows for larger dimensions of the battery cells, enabling larger capacity and increased energy density. Furthermore, it ensures that the minimum path length for gas from any point in the channel to the pressure relief section is less than or equal to 550mm, facilitating the release of gas generated during thermal runaway and improving battery cell safety.

[0033] In some embodiments, the dimensions of the housing along the length direction range from 100mm to 300mm; and / or, the dimensions of the housing along the width direction range from 60mm to 150mm; and / or, the dimensions of the housing along the thickness direction range from 15mm to 80mm.

[0034] By setting the length of the casing to 100mm-300mm, the capacity of the battery cells can be made larger while keeping the length of the channels smaller, so that the channels can be kept unobstructed and can be well vented in the event of thermal runaway.

[0035] Setting the casing width to 60mm-150mm can balance the capacity of the battery cell and the area of ​​the battery cell's length end, giving the battery cell a higher volumetric energy density.

[0036] Setting the outer casing to 15mm-80mm along the thickness direction can balance the structural strength, capacity, and area of ​​the battery cell's length end, giving the battery cell high volumetric energy density and good structural strength.

[0037] In some embodiments, a pressure relief mechanism is provided on at least one side of the peripheral sidewall along the width direction.

[0038] A pressure relief mechanism is provided on the side of the peripheral wall along the width direction, which does not require occupying the dimension of the end of the casing. This allows the tab to be made larger along the width direction, thereby improving the charging and discharging performance of the battery cell.

[0039] In some embodiments, a plurality of pressure relief mechanisms are provided on the peripheral sidewall.

[0040] Multiple pressure relief mechanisms are installed to allow for faster venting of the battery cells in the event of thermal runaway, thereby improving the thermal runaway venting performance of the battery cells and enhancing their safety.

[0041] Secondly, embodiments of this application provide a battery device, including a battery cell as described in the above embodiments.

[0042] Thirdly, embodiments of this application provide an electrical device, including a battery cell or a battery device as described in the above embodiments, wherein the battery cell or battery device is used to store or provide electrical energy.

[0043] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description

[0044] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or exemplary technologies will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0045] Figure 1 is a schematic diagram of the vehicle structure according to some embodiments of this application;

[0046] Figure 2 is an exploded structural diagram of a battery device according to some embodiments of this application;

[0047] Figure 3 is a schematic diagram of the structure of a battery cell according to some embodiments of this application;

[0048] Figure 4 is an exploded structural diagram of a battery cell according to some embodiments of this application;

[0049] Figure 5 is a schematic diagram of the structure of an electrode assembly according to some embodiments of this application;

[0050] Figure 6 is a schematic diagram of the end cap structure of some embodiments of this application;

[0051] Figure 7 is a top view of the battery cell structure of some embodiments of this application;

[0052] Figure 8 is a schematic cross-sectional view of the structure along line AA in Figure 7;

[0053] Figure 9 is a cross-sectional view of the electrode assembly according to some embodiments of this application;

[0054] Figure 10 is a cross-sectional view of the electrode assembly according to some other embodiments of this application;

[0055] Figure 11 is a schematic diagram of the thermal runaway exhaust of a battery cell according to some embodiments of this application;

[0056] Figure 12 is a schematic diagram of the thermal runaway exhaust of a battery cell according to some other embodiments of this application.

[0057] The main labels in the attached figures are as follows: 11, vehicle; 111, controller; 112, motor; 200, battery device; 20, housing; 201, first housing; 202, second housing; 300, battery cell; 301, channel; 302, sub-channel; 31, electrode assembly; 311, main body; 312, tab; 3121. Positive electrode tab; 3122. Negative electrode tab; 313. Electrode; 3131. Positive electrode; 3132. Negative electrode; 3133. Straight section; 3134. Bending section; 314. Diaphragm; 32. Outer shell; 3201. Housing; 32011. Opening; 3202. Peripheral sidewall; 321. First sidewall; 322. Second sidewall; 323. End cap; 324. Liquid injection hole; 325. Isolator; 3251. Vent hole; 33. Electrode terminal; 331. Positive terminal; 332. Negative terminal; 34. Adapter piece; 341. Positive adapter piece; 342. Negative adapter piece; 35. Pressure relief mechanism; 351. Pressure relief section; 36. Support plate; 361. Score; X: Length direction; Z: Width direction; Y: Thickness direction. Embodiments of the present invention

[0058] To make the technical problems, technical solutions, and beneficial effects to be solved by this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and are not intended to limit the scope of this application.

[0059] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein 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 specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0060] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include one or more of that feature.

[0061] In this document, the term "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 throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments in any suitable manner.

[0062] Unless otherwise specified, all embodiments and optional embodiments of this application can be combined to form new technical solutions.

[0063] Unless otherwise specified, all technical features and optional technical features of this application may be combined to form new technical solutions.

[0064] In the description of the embodiments 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, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0065] In the description of the embodiments of this application, the term "multiple" refers to two or more (including two), similarly, "multiple sets" refers to two or more (including two sets), and "multiple pieces" refers to two or more (including two pieces). "Several" means one or more, unless otherwise explicitly specified.

[0066] In the description of the embodiments of this application, the technical terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application.

[0067] In the description of the embodiments of this application, unless otherwise expressly specified and limited, the technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0068] In the description of the embodiments of this application, unless otherwise expressly specified and limited, when an element is referred to as "fixed to" or "set on" another element, it may be directly on or indirectly on the other element. When an element is referred to as "connected to" another element, it may be directly connected to or indirectly connected to the other element.

[0069] In the description of the embodiments in this application, unless otherwise expressly specified and limited, the technical term "proximity" refers to being close in location. For example, among three components A1, A2, and B, the distance between A1 and B is greater than the distance between A2 and B. Therefore, A2 is closer to B than A1, meaning A2 is adjacent to B, or B is adjacent to A2. Similarly, when there are multiple components C, namely C1, C2, ..., C... N If one of the C components, such as C2, is closer to the B component than the other C components, then B is adjacent to C2, or C2 is adjacent to B.

[0070] To improve the energy density of individual battery cells, "blade batteries" are currently widely used. Blade batteries are battery cells whose length is greater than or equal to their width, and whose thickness is less than or equal to their width, with tabs extending from the longitudinal end. Due to their longer length, blade batteries have a larger capacity, thus increasing the energy density of individual cells. Furthermore, after charging and discharging, the electrode expansion along the thickness direction presses against the sidewall of the casing. Therefore, when a battery cell experiences thermal runaway, the gas generated will move along the inner surface of the circumferential sidewall formed by the longitudinal and width directions of the casing to the pressure relief mechanism for release. However, the longer length of these battery cells with tabs at the ends results in an excessively long venting path, which can easily lead to poor venting during thermal runaway.

[0071] Based on the above considerations, in order to improve the problem of poor venting during thermal runaway of a single battery cell, this application provides a battery cell that includes a pressure relief mechanism on its peripheral sidewall and a channel between the peripheral sidewall and the main body of the electrode assembly. This allows for venting and pressure relief during thermal runaway of the electrode assembly. The shortest path lengthwise and widthwise from any point on the channel to the pressure relief section is less than or equal to 550 mm. This ensures that gas generated during thermal runaway at any point on the electrode assembly is discharged into the channel, and the minimum path from the channel to the pressure relief section is less than or equal to 550 mm. The short distance the gas travels during thermal runaway effectively maintains unobstructed venting, facilitating the efficient and rapid discharge of gas and improving the safety of the battery cell.

[0072] In this embodiment of the application, the battery cell can be a secondary battery, which refers to a battery cell that can be recharged to activate the active materials and continue to be used after the battery cell has been discharged.

[0073] The battery cell can be a lithium-ion battery, sodium-ion battery, sodium-lithium-ion battery, lithium metal battery, sodium metal battery, lithium-sulfur battery, magnesium-ion battery, nickel-metal hydride battery, nickel-cadmium battery, lead-acid battery, etc., and the embodiments of this application are not limited to this.

[0074] The battery cell in this application embodiment includes an electrode assembly. The electrode assembly, also known as a bare cell, is a component for storing and releasing electrical energy. The electrode assembly consists of a positive electrode, a negative electrode, and a separator. The electrode assembly primarily operates by the movement of metal ions between the positive and negative electrode plates. The positive electrode includes a positive current collector and a positive active material layer. The positive active material layer is coated on the surface of the positive current collector. The portion of the positive current collector not coated with the positive active material layer protrudes beyond the portion coated with the positive active material layer. This uncoated portion serves as the positive electrode tab, or a metal conductor can be welded onto the positive current collector and led out to serve as the positive electrode tab. Taking a lithium-ion battery as an example, the material of the positive current collector can be aluminum, and the positive active material can be lithium cobalt oxide, lithium iron phosphate, ternary lithium, or lithium manganese oxide, etc. The negative electrode sheet includes a negative current collector and a negative active material layer. The negative active material layer is coated on the surface of the negative current collector. The portion of the negative current collector not coated with the negative active material layer protrudes beyond the portion coated with the negative active material layer. This uncoated portion serves as the negative electrode tab. Alternatively, a metallic conductor can be soldered onto the negative current collector and led out to serve as the negative electrode tab. The material of the negative current collector can be copper, and the negative active material can be carbon or silicon, etc. The positive and negative electrode tabs are collectively referred to as electrode tabs.

[0075] The technical solutions described in the embodiments of this application are applicable to various electrical devices that use individual battery cells, such as mobile phones, portable devices, laptops, electric vehicles, electric toys, power tools, vehicles, ships, and spacecraft. For example, spacecraft include airplanes, rockets, space shuttles, and spacecraft.

[0076] For ease of explanation, an electrical device is provided in one embodiment of this application, with a vehicle as an example.

[0077] Please refer to Figure 1, which is a schematic diagram of the structure of a vehicle 11 provided in some embodiments of this application. The vehicle 11 can be a gasoline-powered vehicle, a natural gas-powered vehicle, or a new energy vehicle. The new energy vehicle can be a pure electric vehicle, a hybrid electric vehicle, or a range-extended electric vehicle, etc. A battery device 200 is installed inside the vehicle 11, and the battery device 200 can be located at the bottom, front, or rear of the vehicle 11. The battery device 200 can be used to power the vehicle 11; for example, the battery device 200 can serve as the operating power source for the vehicle 11. The vehicle 11 may also include a controller 111 and a motor 112. The controller 111 is used to control the battery device 200 to supply power to the motor 112, for example, to meet the power needs of the vehicle 11 during starting, navigation, and driving.

[0078] In some embodiments, the battery device 200 can not only serve as the operating power source for the vehicle 11, but also as the driving power source for the vehicle 11, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 11.

[0079] Referring to Figure 2, this application embodiment provides a battery device 200. The battery device 200 may include one or more battery cell assemblies for providing voltage and capacity. The battery cell assembly may include multiple battery cells 300, which are connected in series, parallel, or mixed connections via a busbar.

[0080] In some embodiments, a battery cell assembly is typically formed by arranging multiple battery cells 300.

[0081] As an example, a battery cell assembly can be a battery module, which is formed by arranging and fixing multiple battery cells 300 together. As another example, a battery module can be formed by bundling multiple battery cells 300 together with cable ties.

[0082] In some embodiments, the battery device 200 may be a battery pack, which includes a housing 20 and one or more individual battery cells housed within the housing 20.

[0083] As an example, the battery cell assembly can be a battery module, and the battery cell assembly can be housed in the housing 20 by fixing the battery module in the housing 20.

[0084] As an example, the battery cell assembly can also be housed in the housing 20 by directly fixing multiple battery cells 300 to the housing 20.

[0085] In some embodiments, the housing 20 may include a first housing 201 and a second housing 202, which are fastened together to form a closed space inside the housing 20 to accommodate the battery cell 300. Here, "closed" refers to covering or shutting off, and can be either sealed or unsealed. The second housing 202 may be a hollow structure with one open end, and the first housing 201 may be a plate-like structure, covering the open side of the second housing 202. The first housing 201 may be the top cover or bottom plate of the housing 20. Alternatively, the first housing 201 and the second housing 202 may both be hollow structures with one open end, with the open side of the first housing 201 covering the open side of the second housing 202.

[0086] In some embodiments, the housing 20 may include a top cover, a frame, and a bottom plate. The top cover and the bottom plate are respectively connected to opposite sides of the frame, thereby forming a closed space inside the housing 20 to accommodate the battery cells 300. The frame refers to a portion of the structure forming the peripheral sidewalls of the housing 20, the top cover refers to a plate-like structure forming the top of the housing 20, and the bottom plate refers to a plate-like structure forming the bottom of the housing 20.

[0087] In some embodiments, the housing 20 may be part of the vehicle's chassis structure. For example, a portion of the housing 20 may be at least a portion of the vehicle's floor, or a portion of the housing 20 may be at least a portion of the vehicle's crossbeams and longitudinal beams.

[0088] Please refer to Figures 3 to 12. According to some embodiments of this application, this application provides a battery cell 300, including a housing 32 and an electrode assembly 31. The housing 32 has a length direction X, a width direction Z, and a thickness direction Y. The length L of the housing 32 is greater than or equal to the width W of the housing 32, and the width W of the housing 32 is greater than or equal to the thickness T of the housing 32. The housing 32 includes two first sidewalls 321 located at opposite ends in the thickness direction Y and a peripheral sidewall 3202 connecting the two first sidewalls 321. The peripheral sidewall 3202 extends along the thickness direction Y. Two first sidewalls 321 are connected to each side; an electrode assembly 31 is disposed in the housing 32. The electrode assembly 31 includes a main body 311. An electrode tab 312 is provided at the end of the main body 311 along the length direction X. A channel 301 is provided between the main body 311 and the peripheral sidewall 3202. A pressure relief mechanism 35 is provided on the peripheral sidewall 3202. The pressure relief mechanism 35 includes a pressure relief part 351. The pressure relief part 351 is connected to the channel 301. The shortest path from any position of the channel 301 along the extension direction of the channel 301 to the pressure relief part 351 is less than or equal to 550 mm.

[0089] The outer casing 32 refers to the structure used to provide a accommodating space to accommodate the electrode assembly 31 and to support and protect the electrode assembly 31.

[0090] Electrode assembly 31 is a component in battery cell 300 that stores and releases electrical energy. As an example, battery cell 300 may include one or more electrode assemblies 31, which are also referred to as bare cells. If there are multiple electrode assemblies 31, they are connected in parallel.

[0091] The battery cell 300 has a length direction, a width direction, and a thickness direction, as shown in Figure 3. The X direction represents the length of the battery cell 300, the Z direction represents the width of the battery cell 300, and the Y direction represents the thickness of the battery cell 300. Since the outer casing 32 defines the shape of the battery cell 300, the length direction of the outer casing 32 and the length direction of the electrode assembly 31 are consistent with the length direction X of the battery cell 300; the width direction of the outer casing 32 and the width direction of the electrode assembly 31 are consistent with the width direction Z of the battery cell 300; and the thickness direction of the outer casing 32 and the thickness direction of the electrode assembly 31 are consistent with the thickness direction Y of the battery cell 300.

[0092] The length L of the outer casing 32 being greater than or equal to the width W of the outer casing 32 means that the dimension of the outer casing 32 along the length direction X is greater than or equal to the dimension of the outer casing 32 along the width direction Z. The width W of the outer casing 32 being greater than or equal to the thickness T of the outer casing 32 means that the dimension of the outer casing 32 along the width direction Z is greater than or equal to the dimension of the outer casing 32 along the thickness direction Y.

[0093] The first sidewall 321 refers to one sidewall of the outer shell 32, and the two first sidewalls 321 define the thickness of the outer shell 32, that is, the two first sidewalls 321 are located at opposite ends of the thickness direction Y of the outer shell 32.

[0094] The peripheral sidewall 3202 refers to the sidewall provided on the outer shell 32 between the two first sidewalls 321. The peripheral sidewall 3202 connects to the two first sidewalls 321 on both sides along the thickness direction Y to form an accommodating space.

[0095] The electrode assembly 31 is disposed in the housing 32 so as to support and protect the electrode assembly 31 through the housing 32.

[0096] The main body 311 is the main part of the electrode assembly 31. The tab 312 is used in the electrode assembly 31 to connect to an external circuit so that the current can flow through the main body 311 for charging and discharging.

[0097] The provision of a tab 312 at one end of the main body 311 along the length direction X means that a tab 312 is provided at one end of the main body 311 along the length direction X, or that tabs 312 are provided at opposite ends of the main body 311 along the length direction X.

[0098] Channel 301 refers to a channel structure formed between the main body 311 and the inner surface of the peripheral sidewall 3202, which allows gas to flow. The channel 301 between the main body 311 and the peripheral sidewall 3202 allows gas generated during thermal runaway at a certain location on the electrode assembly 31 to flow along the channel 301. The size of the main body 311 can be set smaller than the size of the peripheral sidewall 3202 to form the channel 301 between the inner surface of the main body 311 and the peripheral sidewall 3202.

[0099] The pressure relief mechanism 35 is used to release internal pressure when the internal pressure or temperature of the battery cell 300 reaches a threshold. The pressure relief mechanism 35 can be a structure such as an explosion-proof valve or explosion-proof disc mounted on the peripheral sidewall 3202. The pressure relief section 351 refers to the part of the pressure relief mechanism 35 used to discharge gas for pressure relief. The pressure relief section 351 can be an easily damaged exhaust part of the explosion-proof disc or explosion-proof valve. The pressure relief section 351 is connected to the channel 301, so that in the event of thermal runaway, the gas in the channel 301 can flow to the pressure relief section 351 and be discharged.

[0100] Since channel 301 is a spatial structure formed between the main body 311 and the inner surface of the peripheral sidewall 3202, it is a frame-like structure surrounding the main body 311. Accordingly, channel 301 includes two segments extending along the length direction X and two segments extending along the width direction, and the four segments are connected end to end to form a frame-like channel 301 structure. The shortest path from any position of channel 301 along the extension direction of channel 301 to pressure relief section 351 is less than or equal to 550 mm. Please refer to Figures 11 and 12. Since channel 301 is a frame-like structure surrounding electrode assembly 31, gas at any position on channel 301 flows along channel 301 to pressure relief section 351 via two paths in opposite directions. Both paths extend along the length direction X and / or the width direction Z, and the shorter of the two paths is less than or equal to 550 mm. Due to the thermal runaway of electrode assembly 31, gas is generated, increasing the internal pressure of housing 32. When pressure relief section 351 is opened, the gas will reach pressure relief section 351 more quickly along a shorter path. Therefore, the length of this path is directly related to the thermal runaway exhaust efficiency in housing 32. Setting the shortest path length from any position of channel 301 to pressure relief section 351 along the extension direction of channel 301 to less than or equal to 550 mm can reduce exhaust resistance and ensure smooth exhaust.

[0101] Please refer to Figure 11. Since the straight portion 3133 of the electrode assembly 31 abuts against the first sidewall 321 of the outer casing 32, when thermal runaway occurs at a certain position M on the electrode assembly 31, the gas generated can reach the pressure relief section 351 via two paths L1 and L2. Path L1 is L11, H11, and L12. Therefore, the gas path along path L1 is L10 = L11 + L12 in the length direction X and H11 in the width direction Z. The length of the gas along path L1 is:

[0102] L1 = L10 + H11 = L11 + L12 + H11. Path L2 consists of L21, H21, and L22 leading to the pressure relief section 351. The gas along path L2 has a length direction (X) of L20 = L21 + L22 and a width direction (Z) of H21. Therefore, the length of the gas along path L2 is: L2 = L20 + H21 = L21 + L22 + H21. Since L1 is less than L2, the gas at position M can reach the pressure relief section 351 more quickly along path L1. Since L1 ≤ 550 mm, the gas at position M can quickly reach the pressure relief section 351 for discharge, ensuring smooth exhaust.

[0103] Please refer to Figure 12. Since the straight portion 3133 of the electrode assembly 31 abuts against the first sidewall 321 of the outer casing 32, when the gas generated by thermal runaway at a certain position N on the electrode assembly 31 can reach the pressure relief part 351 through two paths L1 and L2. Path L1 is along L11 to reach the pressure relief part 351. Then, the gas along path L1 has a path length X of L10 = L11 and a path width Z of 0. Therefore, the length of the gas along path L1 is: L1 = L10 = L11. The path L2, consisting of L21, H21, L22, and H22, leads to the pressure relief section 351. The gas along path L2 has a length direction (X) of L20 = L21 + L22 + L23 and a width direction (Z) of H20 = H21 + H22. Therefore, the length of the gas along path L2 is: L2 = L20 + H20 = L21 + L22 + L23 + H21 + H22. Since L1 is less than L2, the gas at position N can reach the pressure relief section 351 more quickly along path L1. Since L1 ≤ 550 mm, the gas at position N can quickly reach the pressure relief section 351 for discharge, ensuring smooth exhaust.

[0104] In the technical solution of this application embodiment, by providing a channel 301 between the peripheral sidewall 3202 and the main body 311 of the electrode assembly 31, and making the shortest path from any position on the channel 301 along the extension direction of the channel 301 to the pressure relief part 351 less than or equal to 550mm, the gas generated by thermal runaway at any position on the electrode assembly 31 is discharged to the channel 301, and the minimum path from the channel 301 to the pressure relief part 351 is less than or equal to 550mm, thereby facilitating the discharge of gas generated by thermal runaway, ensuring smooth exhaust, and improving the safety of the battery cell 300.

[0105] In some embodiments, as shown in Figures 3, 8 to 12, the electrode assembly 31 can be a wound structure or a stacked structure. The embodiments of this application are not limited to this. Referring to Figure 9, in a wound structure, the tabs 312 are typically welded to the current collector, and then arranged in the order of positive electrode 3131 – separator 314 – negative electrode 3132 – separator 314; then wound to form a cylindrical or square battery cell. Referring to Figure 10, in a stacked structure, the tabs 312 are typically led out from the current collector, and the positive electrode 3131, negative electrode 3132, and separator 314 are arranged in the order of positive electrode 3131 – separator 314 – negative electrode 3132 – separator 314, stacked layer by layer to form a stacked battery cell; wherein, the separator 314 can be cut and directly stacked as separator sheets, or the separator 314 can be stacked in a Z-shaped fold without cutting it. The separator 314 can be made of materials such as PP (Polypropylene) or PE (Polyethylene). Separator 314 is an insulating film disposed between the positive electrode 3131 and the negative electrode 3132. Its main function is to isolate the positive and negative electrodes and prevent electrons in the battery from passing freely, thus preventing short circuits, while allowing ions in the electrolyte to pass freely between the positive and negative electrodes to form a circuit. The positive electrode 3131 and the negative electrode 3132 are collectively referred to as electrode 313.

[0106] In some embodiments, the main body 311 includes an electrode 313, which includes a straight portion 3133. The straight portion 3133 refers to the straight section of the electrode 313. Referring to FIG9, for a wound electrode assembly 31, the electrode 313 is wound to form a straight portion 3133 and a bent portion 3134, with the bent portion 3134 connected to the straight portion 3133. Referring to FIG10, for a stacked electrode assembly 31, each electrode 313 is a straight portion 3133. The straight portions 3133 of the electrode assembly 31 are multi-layered, and the multi-layered straight portions 3133 are stacked along the thickness direction Y of the housing 32. Due to the charging and discharging of the battery cell 300, its electrode assembly 31 often expands and deforms, increasing the thickness of its electrode 313, thus increasing the thickness of the electrode assembly 31 so that the straight portion 3133 abuts against the first sidewall 321.

[0107] In some embodiments, the channel 301 may also have a portion of the electrode 313, such as the positive electrode 3131, with a size smaller than that of the sidewall, so that the gap between the electrode 313, such as the positive electrode 3131, and the inner surface of the peripheral sidewall 3202 forms the channel 301.

[0108] In some embodiments, the tab 312 includes a positive tab 3121 and a negative tab 3122, which are used to connect the positive and negative terminals of an external circuit, respectively. The positive tab 3121 and the negative tab 3122 can be located on the same side of the main body 311, or they can be disposed on different sides of the main body 311, such as on opposite sides of the main body 311.

[0109] Please refer to Figures 3 to 6. In some embodiments, the housing 32 includes a housing 3201 and an end cap 323. The electrode assembly 31 is installed in the housing 3201, and the end cap 323 covers the housing 3201.

[0110] End cap 323 refers to a component that covers the opening of housing 3201 to isolate the internal environment of battery cell 300 from the external environment. The shape of end cap 323 can be adapted to the shape of housing 3201 to fit onto housing 3201. Optionally, end cap 323 can be made of a material with a certain hardness and strength (such as aluminum alloy), so that end cap 323 is not easily deformed when subjected to compression and impact, so that battery cell 300 can have higher structural strength and improved reliability. The material of end cap 323 can also be various, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., and this application does not impose any special limitations on it.

[0111] The housing 3201 is an assembly used to cooperate with the end cap 323 to form the internal environment of the battery cell 300, wherein the formed internal environment can accommodate the electrode assembly 31, electrolyte, and other components. The housing 3201 can be of various shapes and sizes, such as cuboid, cylindrical, hexagonal prism, etc. Specifically, the shape of the housing 3201 can be determined according to the specific shape and size of the battery cell 300. The material of the housing 3201 can be various, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., and this application does not impose any special limitations on it.

[0112] In some embodiments, an end cap 323 is provided at the end of the housing 3201 in the length direction X, so that the tab 312 at the end of the electrode assembly 31 in the length direction X can be led out.

[0113] In some embodiments, the housing 32 is provided with an injection hole 324. The injection hole 324 refers to a hole structure for injecting electrolyte into the housing 32. After the electrode assembly 31 is manufactured, it needs to be installed in the housing 3201 and electrolyte is injected so that the electrode assembly 31 is immersed in the electrolyte, allowing the electrode assembly 31 to fully absorb the electrolyte. The electrolyte can provide some active ions for use as conductive ions during the charging and discharging process; in addition, the electrolyte provides ion channels, or carriers, allowing ions to move freely within them to achieve electrical conduction between the electrodes 313. The housing 32 is provided with an injection hole 324 to add electrolyte into the housing 32.

[0114] As an example, the injection port 324 can be provided on the housing 3201. Of course, the injection port 324 can also be provided on the end cap 323.

[0115] In some embodiments, the battery cell 300 includes electrode terminals 33 disposed on the housing 32 and connected to the tabs 312 of the electrode assembly 31. Electrode terminals 33 refer to conductive elements disposed on the housing 32. The connection between electrode terminals 33 and the tabs 312 of the electrode assembly 31 allows for the output of electrical energy from the battery cell 300 or the charging of the battery cell 300. The battery cell 300 typically has two electrode terminals 33: a positive terminal 331 and a negative terminal 332. The positive terminal 331 is connected to the positive tab 3121 of the electrode assembly 31, and the negative terminal 332 is connected to the negative tab 3122 of the electrode assembly 31.

[0116] In some embodiments, the battery cell 300 further includes two adapter pieces 34, each corresponding to one of the two electrode terminals 33. Each tab 312 is connected to its corresponding electrode terminal 33 via the adapter piece 34, facilitating a more secure connection between the tab 312 and the electrode terminal 33. The two adapter pieces 34 are a positive adapter piece 341 and a negative adapter piece 342. The positive adapter piece 341 connects the positive tab 3121 to the positive terminal 331, and the negative adapter piece 342 connects the negative tab 3122 to the negative terminal 332.

[0117] In some embodiments, the peripheral sidewall 3202 includes second sidewalls 322 located at opposite ends in the width direction Z of the housing 32 and end caps 323 located at opposite ends in the length direction X of the housing 32. The second sidewalls 322 refer to a sidewall of the housing 32, and the two second sidewalls 322 define the width of the housing 32, i.e., the two second sidewalls 322 are located at opposite ends in the width direction Z of the housing 32. The end caps 323 refer to a sidewall of the housing 32, and the two end caps 323 define the length of the housing 32, i.e., the two end caps 323 are located at opposite ends in the length direction X of the housing 32.

[0118] In some embodiments, the housing 32 includes a housing 3201 and an end cap 323, and when the housing 32 includes a first sidewall 321 and a peripheral sidewall 3202, the housing 3201 includes a first sidewall 321 and a second sidewall 322, that is, the second sidewall 322 of the housing 32 and the end cap 323 constitute the peripheral sidewall 3202 of the housing 32.

[0119] In some embodiments, when the peripheral sidewall 3202 includes a second sidewall 322 and an end cap 323, a pressure relief mechanism 35 may be provided on the second sidewall 322, or on the end cap 323, or both the second sidewall 322 and the end cap 323 may be provided with a pressure relief mechanism 35.

[0120] In some embodiments, when the housing 32 includes an end cap 323, the electrode terminal 33 can be disposed on the end cap 323 so as to be connected to the tab 312 of the electrode assembly 31 and also to facilitate installation on the housing 3201.

[0121] In some embodiments, when end caps 323 are provided at both opposite ends of the housing 3201, tabs 312 can be led out from opposite ends of the main body 311 in the length direction X of the electrode assembly 31. For example, a positive tab 3121 can be led out from one end of the main body 311, and a negative tab 3122 can be led out from the other end. A positive terminal 331 is provided on one end cap 323, and a negative terminal 332 is provided on the other end cap 323. This allows for easy connection of the negative tab 3122 to the negative terminal 332 and the positive tab 3121 to the positive terminal 331, thereby enabling the positive and negative terminals 331 and 332 to be led out from opposite ends of the housing 32. This structure allows for a larger dimension of the tabs 312 in the width direction Z, thereby improving the charging and discharging performance of the electrode assembly 31.

[0122] In some embodiments, a positive electrode tab 3121 and a negative electrode tab 3122 may be simultaneously led out from one end of the main body 311. Correspondingly, a positive terminal 331 and a negative terminal 332 are provided on an end cap 323 to connect the positive electrode tab 3121 and the negative electrode tab 3122 of the electrode assembly 31.

[0123] In some embodiments, electrode terminals 33 may also be provided on other sidewalls of the housing 32, such as on the second sidewall 322, to be connected to the corresponding tabs 312 of the electrode assembly 31.

[0124] In some embodiments, please refer to Figures 4, 8, 11 and 12, the distance between the two second sidewalls 322 of the peripheral sidewall 3202 is W1, and the dimension of the electrode assembly 31 along the width direction Z is W2, 0.01mm≤W1-W2≤8.75mm.

[0125] The distance W1 between the two second sidewalls 322 is the dimension of the accommodating space of the outer casing 32 along the width direction Z. The dimension W2 of the electrode assembly 31 along the width direction Z is also the width of the electrode assembly 31.

[0126] The range of W1-W2 is set to 0.01mm-8.75mm, that is, the difference between the distance W1 between the two second sidewalls 322 and the dimension W2 of the electrode assembly 31 along the width direction Z is 0.01mm-8.75mm. For example, W1-W2 can be 0.01mm, 0.05mm, 0.1mm, 0.5mm, 0.8mm, 1mm, 1.5mm, 2mm, 2.5mm, 3mm, 3.5mm, 4mm, 4.5mm, 5mm, 5.5mm, 6mm, 6.5mm, 7mm, 7.5mm, 8mm, 8.5mm, 8.75mm, etc.

[0127] Channel 301 includes sub-channel 302, which is the portion of channel 301 located between the second sidewall 322 and the electrode assembly 31. That is, the portion of channel 301 arranged along the length direction X is sub-channel 302.

[0128] The difference between the distance W1 between the two second sidewalls 322 and the dimension W2 of the electrode assembly 31 along the width direction Z can be the maximum dimension of the sub-channel 302 along the width direction Z. By setting the range of W1-W2 to 0.01mm-8.75mm, the electrode assembly 31 can occupy a larger proportion along the width direction Z in the housing 32 while allowing the sub-channel 302 to vent well, thereby improving the volumetric energy density.

[0129] With the above structure, the width of the portion of the channel 301 at both ends of the electrode assembly 31 in the width direction Z can be larger, so as to facilitate good exhaust in the event of thermal runaway and better maintain unobstructed exhaust, thereby improving the safety of the battery cell 300.

[0130] In some embodiments, referring to Figures 4, 8, 11, and 12, channel 301 includes a sub-channel 302 extending along the length direction X. The cross-sectional area of ​​sub-channel 302 perpendicular to the length direction X is S. The capacity of the battery cell 300 is C, and the capacitance is 0.05 mm² / Ah (mm²). 2 / Ah)≤S / C≤0.7mm 2 / Ah.

[0131] Sub-channel 302 refers to the portion of channel 301 that extends along the length direction X. Since channel 301 is frame-shaped, there are two sub-channels 302, located at opposite ends of the width direction Z of electrode assembly 31.

[0132] The cross-sectional area S of sub-channel 302 along the length direction X is the cross-sectional area of ​​sub-channel 302. The capacity C of battery cell 300 refers to the amount of electricity that battery cell 300 can release under certain discharge conditions (such as a certain discharge rate, temperature, etc.), and its unit is usually ampere-hour (Ah) or milliampere-hour (mAh).

[0133] The battery cell 300 has a large capacity, and correspondingly, the electrode assembly 31 will also be larger in size. In the event of thermal runaway, more gas will be generated. The larger the cross-sectional area S of the sub-channel 302, the easier it is for gas to flow in the sub-channel 302. Therefore, the cross-sectional area S of the sub-channel 302 is directly related to its exhaust capacity.

[0134] Set the S / C range to 0.05mm 2 / Ah-0.7mm 2 / Ah, such as S / C can be 0.05mm 2 / Ah, 0.1mm 2 / Ah, 0.15mm 2 / Ah, 0.2mm 2 / Ah, 0.25mm 2 / Ah, 0.3mm 2 / Ah, 0.35mm 2 / Ah, 0.4mm 2 / Ah, 0.45mm 2 / Ah, 0.5mm 2 / Ah, 0.55mm 2 / Ah, 0.6mm 2 / Ah, 0.65mm 2 / Ah, 0.7mm 2 / Ah, etc., can make the capacity of the battery cell 300 and the cross-sectional area S of the sub-channel 302 reach a good balance, so that the battery cell 300 can both vent well in the case of thermal runaway and have a high volumetric energy density.

[0135] The above-mentioned structural design allows the sub-channel 302 to discharge the gas generated by the thermal runaway of the electrode assembly 31 more quickly and effectively, thereby improving the safety of the battery cell 300.

[0136] In some embodiments, please refer to Figures 3, 8, 11 and 12. The sub-channel 302 has a first dimension L01 along the thickness direction Y and a second dimension L02 along the width direction Z, S = L01 * L02. The dimension of L01 ranges from 15mm to 80mm, and the dimension of L02 ranges from 1mm to 10mm.

[0137] Since the sub-channel 302 is the portion of the channel 301 located between the second sidewall 322 and the electrode assembly 31, and the first dimension L01 is the dimension of the sub-channel 302 along the thickness direction Y, the first dimension L01 can be the distance between the two first sidewalls 321. The second dimension L02 is the dimension of the sub-channel 302 along the width direction Z, and the second dimension L02 can be the distance between the side surfaces of the two main body portions 311 and the second sidewall 322.

[0138] The size of L01 directly affects the thickness of the electrode assembly 31, and thus the size of L01 is positively correlated with the capacity of the electrode assembly 31. The size of L01 also affects the spatial dimension of the end of the casing 32 in the length direction X that accommodates the tab 312. The size of L01 is also positively correlated with the spatial dimension of the end of the casing 32 in the length direction X that accommodates the tab 312. Moreover, the size of L01 is also positively correlated with the cross-sectional area S of the sub-channel 302. The size range of L01 is 15mm-80mm, such as 15mm, 20mm, 25mm, 30mm, 35mm, 40mm, 50mm, 60mm, 70mm, 80mm, etc., which can balance the energy density of the battery cell 300, the capacity of the battery cell 300 and the cross-sectional area S of the sub-channel 302, so as to ensure that gas flows from the sub-channel 302 to the pressure relief section 351 in the event of thermal runaway.

[0139] The size of L02 directly affects the width of the electrode assembly 31, and thus the size of L02 is positively correlated with the capacity of the electrode assembly 31. Moreover, the size of L02 is also positively correlated with the cross-sectional area S of the sub-channel 302. The size range of L02 is 1mm-10mm, such as the size of L01 being 1mm, 2mm, 3mm, 4mm, 5mm, 6mm, 7mm, 8mm, 9mm, 10mm, etc., which can balance the energy density and capacity of the battery cell 300 with the cross-sectional area S of the sub-channel 302, so that gas can flow well from the sub-channel 302 to the pressure relief section 351 in the event of thermal runaway.

[0140] By setting the first dimension L01 of the sub-channel 302 along the thickness direction Y to 15mm-80mm and the second dimension L02 of the sub-channel 302 along the width direction Z to 1mm-10mm, the battery cell 300 can have a high volumetric energy density and can effectively balance the energy density of the battery cell 300 with the cross-sectional area S of the sub-channel 302, so that in the event of thermal runaway, the generated gas can flow smoothly and unobstructedly from the sub-channel 302 to the pressure relief section 351.

[0141] In some embodiments, please refer to Figures 4, 8, 11 and 12, the capacity C of the battery cell 300 ranges from 5Ah to 250Ah.

[0142] The capacity C of a single 300 battery cell ranges from 5Ah to 250Ah. For example, the capacity C of a single 300 battery cell can be 5Ah, 10Ah, 15Ah, 20Ah, 30Ah, 40Ah, 50Ah, 60Ah, 80Ah, 100Ah, 120Ah, 150Ah, 180Ah, 200Ah, 220Ah, 250Ah, etc.

[0143] A larger capacity in the battery cell 300 allows for a larger electrode assembly 31 within the casing 32. With a fixed casing 32 size, a larger capacity in the battery cell 300 results in a higher volumetric density. This larger capacity also leads to a larger electrode assembly 31, which in the event of thermal runaway tends to generate more gas. Setting the capacity of the battery cell 300 to 5Ah-250Ah allows for a higher volumetric density, and also ensures that the gas generated during thermal runaway can flow effectively from the channel 301 to the pressure relief section 351 for discharge.

[0144] In some embodiments, referring to Figures 3, 4, and 8, the housing 32 includes a housing 3201 and an end cap 323. An opening 32011 is provided at the end of the housing 3201 along its length X direction, and the end cap 323 covers the opening 32011. Providing an opening 32011 at the end of the housing 3201 along its length X direction facilitates the insertion of the electrode assembly 31 into the housing 3201. The end cap 323 is placed over the opening 32011; for example, the end cap 323 can be bonded or welded to the housing 3201 to seal the housing 32011, thereby effectively protecting the electrode assembly 31.

[0145] In some embodiments, openings 32011 can be provided at both opposite ends of the housing 3201 along the length X direction, and correspondingly, two end caps 323 are provided, which are respectively sealed over the two openings 32011. This structure facilitates the processing and manufacturing of the housing 3201, and also facilitates the extension of the tabs 312 from both ends of the main body 311 of the electrode assembly 31.

[0146] In some embodiments, an opening 32011 may be provided at one end of the housing 3201 in the length direction X, and correspondingly, an end cap 323 may be provided to cover the opening 32011.

[0147] In some embodiments, please refer to Figures 4 and 6. The inner surface of the end cap 323 is provided with an isolation member 325, and the isolation member 325 has a vent hole 3251 along the width direction Z.

[0148] The isolator 325 refers to an electrical connection component that can be used within the housing 3201 to isolate the electrical connection component from the end cap 323, thereby reducing the risk of short circuits. For example, the isolator 325 may be made of plastic, rubber, or the like.

[0149] Vent hole 3251 refers to a through hole structure provided on the isolation member 325 and extending along the width direction Z.

[0150] Since the end cap 323 is part of the peripheral sidewall 3202, a channel 301 is provided between the main body 311 of the electrode assembly 31 and the inner surface of the peripheral sidewall 3202. An isolator 325 is provided on the end cap 323. During assembly, the isolator 325 may abut against the main body 311 to limit the distance between the main body 311 and the end cap 323, creating a certain space between the end cap 323 and the main body 311 to accommodate structures such as the tab 312. Thus, the isolator 325 may block the channel 301. A vent 3251 is provided on the isolator 325 to connect the channel 301. Correspondingly, the vent 3251 also becomes part of the channel 301, so that in the event of thermal runaway of the battery cell 300, the gas generated by the electrode assembly 31 can flow smoothly from the channel 301 to the pressure relief section 351 for pressure relief and outflow.

[0151] An isolator 325 is provided on the end cap 323 to limit the distance between the main body 311 and the end cap 323 so as to accommodate the electrode tab 312 on the main body 311; a vent 3251 is provided on the isolator 325, which can serve as part of the channel 301, thereby effectively venting the generated gas in the event of thermal runaway of the electrode assembly 31 and improving the safety of the battery cell 300.

[0152] In some embodiments, a vent 3251 may be provided at the end of the isolation member 325 along the width direction Z, and the vent 3251 may be located at the middle position of the isolation member 325 along the thickness direction Y for processing and manufacturing.

[0153] In some embodiments, the insulating member 325 may have two vent holes 3251 at its end along the width direction Z, and the two vent holes 3251 may be located on both sides of the insulating member 325 along the thickness direction Y, so that the positions of the vent holes 3251 are staggered from the positions of the tabs 312, so that gas can flow through the vent holes 3251. In some embodiments, the insulating member 325 may also have a greater number of vent holes 3251 at its end along the width direction Z, so as to allow gas to flow in the event of thermal runaway.

[0154] In some embodiments, please refer to Figures 3, 4 and 8, the pressure resistance of the connection between the end cap 323 and the housing 3201 ranges from 0.5 MPa to 5 MPa.

[0155] Pressure resistance refers to the maximum pressure an object can withstand without being destroyed.

[0156] The pressure resistance of the connection between the end cap 323 and the housing 3201 refers to the maximum pressure that the connection between the end cap 323 and the housing 3201 can withstand without being damaged when the housing 3201 is filled with gas or liquid to increase the pressure in the housing 32.

[0157] The withstand pressure range of the connection between the end cap 323 and the housing 3201 is 0.5MPa-5MPa. For example, the withstand pressure of the connection between the end cap 323 and the housing 3201 can be 0.5MPa, 1MPa, 1.5MPa, 2MPa, 2.5MPa, 3MPa, 3.5MPa, 4MPa, 4.5MPa, 5MPa, etc., to ensure that the battery cell 300 has good structural strength and airtightness.

[0158] In some embodiments, referring to Figures 4, 8, 11 and 12, when the channel 301 includes a sub-channel 302 extending along the length direction X, the sub-channel 302 communicates with the vent 3251.

[0159] A vent 3251 is provided on the isolation member 325 and communicates with the sub-channel 302 of the channel 301 so that a channel 301 is formed between the main body 311 and the peripheral sidewall 3202, so that the gas generated by thermal runaway can flow to the pressure relief part 351 for discharge.

[0160] In some embodiments, referring to Figures 4, 8, 11 and 12, the cross-sectional area of ​​the vent 3251 along the width direction Z is greater than or equal to the cross-sectional area of ​​the sub-channel 302 along the length direction X.

[0161] By setting the cross-sectional area of ​​the vent 3251 to be greater than or equal to the cross-sectional area of ​​the sub-channel 302, the flow resistance of gas in the vent 3251 is smaller. In the event of thermal runaway of the electrode assembly 31, the generated gas can be discharged better, thereby improving the safety of the battery cell 300.

[0162] In some embodiments, please refer to Figures 3 and 4, the outer casing 32 is an aluminum casing, a steel casing, or a titanium casing.

[0163] An aluminum shell refers to a shell structure made of aluminum or aluminum alloy.

[0164] A steel shell refers to a shell structure made of steel.

[0165] A titanium shell refers to a shell structure made of titanium metal or titanium alloy.

[0166] The outer casing 32 uses an aluminum casing, which is lightweight and low-cost. The outer casing 32 uses a steel casing, which has high structural strength and low cost. The outer casing 32 uses a titanium casing, which has high structural strength and good corrosion resistance.

[0167] In some embodiments, referring to Figures 3 and 4, when the housing 32 includes a housing 3201 and an end cap 323, the housing 3201 and the end cap 323 may be made of the same material. Of course, the housing 3201 and the end cap 323 may also be made of different materials.

[0168] In some embodiments, the perimeter of the outer shell 32 is K, K = 2*(L+W), and 320mm≤K≤1100mm, where L is the length of the outer shell 32 and W is the width of the outer shell 32.

[0169] The length of the outer shell 32 refers to its dimension along the length direction X. The width of the outer shell 32 refers to its dimension along the width direction Z. The perimeter of the outer shell 32 refers to the perimeter of its projected shape along the thickness direction Y. The perimeter of the outer shell 32 is the sum of its two lengths L and two widths W, i.e., K = 2*(L + W).

[0170] The perimeter K of the outer casing 32 ranges from 320mm to 1100mm. For example, the perimeter K of the outer casing 32 can be 320mm, 350mm, 380mm, 400mm, 450mm, 500mm, 550mm, 600mm, 650mm, 700mm, 750mm, 800mm, 850mm, 900mm, 950mm, 1000mm, 1050mm, 1100mm, etc.

[0171] By setting the perimeter of the outer casing 32 to a range of 320mm-1100mm, the length and width of the battery cell 300 can be set to be larger, thereby increasing the capacity of the battery cell 300 and improving its energy density. Furthermore, the minimum path length for gas from any position on the channel 301 to reach the pressure relief section 351 for pressure relief can be less than or equal to 550mm, which facilitates the discharge of gas generated by thermal runaway, ensuring smooth exhaust and improving the safety of the battery cell 300.

[0172] In some embodiments, please refer to Figures 3 and 4, the size of the housing 32 along the length direction X ranges from 100mm to 300mm.

[0173] The dimension of the outer casing 32 along the length direction X also refers to the length L of the outer casing 32. The dimension of the outer casing 32 along the length direction X ranges from 100mm to 400mm, such as the length L of the outer casing 32 being 100mm, 120mm, 150mm, 180mm, 200mm, 220mm, 250mm, 280mm, 300mm, etc.

[0174] By setting the size of the outer casing 32 along the length direction X to 100mm-300mm, the capacity of the battery cell 300 can be made larger, while the size of the channel 301 along the length direction X can be made smaller, so that the channel 301 can be kept unobstructed, so as to facilitate good exhaust in the event of thermal runaway.

[0175] In some embodiments, please refer to Figures 3 and 4, the size of the housing 32 along the width direction Z ranges from 60mm to 150mm.

[0176] The dimension of the outer casing 32 along the width direction Z also refers to the width W of the outer casing 32. The dimension of the outer casing 32 along the width direction Z ranges from 60mm to 150mm, such as the length W of the outer casing 32, which can be 60mm, 80mm, 90mm, 100mm, 120mm, 120mm, 150mm, etc. Since the electrode assembly 31 has tabs 312 led out from its end along the length direction X, and correspondingly, the tabs 312 are located at the end of the outer casing 32 along the length direction X, a receiving space is provided at the end of the outer casing 32 along the length direction X to accommodate the tabs 312. The size of this receiving space is positively correlated with the width and thickness of the outer casing 32. That is, the larger the width of the outer casing 32, the larger the size of this receiving space, and correspondingly, the larger the space occupied inside the outer casing 32. Setting the dimension of the outer casing 32 along the width direction Z to 60mm-150mm can balance the capacity of the battery cell 300 and the area size of the end of the battery cell 300 along the length direction X, so that the battery cell 300 has a higher volumetric energy density.

[0177] In some embodiments, as shown in Figures 3 and 4, the size of the housing 32 along the thickness direction Y ranges from 15 mm to 80 mm.

[0178] The dimension of the outer casing 32 along the thickness direction Y also refers to the thickness T of the outer casing 32. The dimension of the outer casing 32 along the thickness direction Y ranges from 20mm to 80mm, such as the thickness T of the outer casing 32 can be 15mm, 20mm, 25mm, 30mm, 35mm, 40mm, 50mm, 60mm, 70mm, 80mm, etc. Because a receiving space is provided at the end of the outer casing 32 along the length direction X to accommodate the tab 312, the size of this receiving space is directly related to the width and thickness of the outer casing 32. That is, the greater the thickness of the outer casing 32, the larger the size of this receiving space, and correspondingly, the larger the space occupied inside the outer casing 32.

[0179] Setting the outer casing 32 to a thickness Y dimension of 15mm-80mm can balance the structural strength of the battery cell 300, the capacity of the battery cell 300, and the area of ​​the battery cell 300 at its length X end, so that the battery cell 300 has a high volumetric energy density and good structural strength.

[0180] In some embodiments, as shown in Figures 3 and 4, the peripheral sidewall 3202 is provided with a pressure relief mechanism 35 on at least one side along the width direction Z.

[0181] At least one side of the peripheral sidewall 3202 along the width direction Z refers to one or both of the two sidewalls located at both ends of the width direction Z on the peripheral side portion. When the peripheral sidewall 3202 includes a second sidewall 322, at least one side of the peripheral sidewall 3202 along the width direction Z refers to one second sidewall 322, or it may be two second sidewalls 322.

[0182] The provision of a pressure relief mechanism 35 on at least one side of the peripheral sidewall 3202 along the width direction Z means that a pressure relief mechanism 35 is provided on one side of the peripheral sidewall 3202 along the width direction Z or on the two sidewalls at both ends of the peripheral sidewall 3202 along the width direction Z.

[0183] A pressure relief mechanism 35 is provided on the side of the peripheral wall 3202 along the width direction Z, which does not require occupying the size of the end of the housing 32. This allows the tab 312 to be made larger along the width direction Z, thereby improving the charging and discharging performance of the battery cell 300.

[0184] In some embodiments, please refer to Figures 3 and 4, a plurality of pressure relief mechanisms 35 are provided on the peripheral sidewall 3202.

[0185] "Multiple" refers to two or more.

[0186] Multiple pressure relief mechanisms 35 are provided so that the battery cell 300 can vent more quickly in the event of thermal runaway, thereby improving the thermal runaway venting performance of the battery cell 300 and thus enhancing the safety of the battery cell 300.

[0187] In some embodiments, please refer to Figures 3 and 4, a pressure relief mechanism 35 may be provided on the second sidewall 322, or two, three or more pressure relief mechanisms 35 may be provided.

[0188] In some embodiments, referring to Figures 3 and 4, the battery cell 300 further includes a tray 36, which is mounted in the housing 32 to position the electrode assembly 31. The tray 36 allows for better positioning of the electrode assembly 31 and reduces deformation of the electrode assembly 31's edges caused by the rounded corners of the housing 32. The tray 36 can be made of materials such as ceramic, plastic, or silicone.

[0189] In some embodiments, the electrode assembly 31 is provided with a support plate 36 at at least one end along the width direction Z to position the electrode assembly 31.

[0190] In some embodiments, the tray 36 is provided with a notch 361 at the position corresponding to the pressure relief part 351, so that in the event of thermal runaway of the battery cell 300 and generation of gas, the notch 361 on the tray 36 can be broken through, so that the gas can reach the pressure relief part 351 and be discharged from the pressure relief part 351, thereby reducing the risk of the tray 36 blocking or blocking the pressure relief part 351.

[0191] According to some embodiments of this application, a battery cell 300 is provided, including a housing 32 and an electrode assembly 31. The housing 32 has a length direction X, a width direction Z, and a thickness direction Y. The length L of the housing 32 is greater than or equal to the width W of the housing 32, and the width W of the housing 32 is greater than or equal to the thickness T of the housing 32. The housing 32 includes two first sidewalls 321 located at opposite ends in the thickness direction Y and a peripheral sidewall 3202 connecting the two first sidewalls 321. The peripheral sidewall 3202 is divided into two sides along the thickness direction Y. Two first sidewalls 321 are connected. An electrode assembly 31 is disposed within the housing 32. The electrode assembly 31 includes a main body 311, with an electrode tab 312 at one end along the length direction X. A channel 301 is provided between the main body 311 and the peripheral sidewall 3202. A pressure relief mechanism 35 is provided on the peripheral sidewall 3202, including a pressure relief part 351 connected to the channel 301. The shortest path from any position of the channel 301 along its extension direction to the pressure relief part 351 is less than or equal to 550 mm. The peripheral sidewall 3202 includes second sidewalls 322 located at opposite ends in the width direction Z of the housing 32 and end caps 323 located at opposite ends in the length direction X of the housing 32. The distance between the two second sidewalls 322 of the peripheral sidewall 3202 is W1, and the dimension of the electrode assembly 31 along the width direction Z is W2, where 0.01 mm ≤ W1 - W2 ≤ 8.75 mm. Channel 301 includes a sub-channel 302 extending along the length direction X. The cross-sectional area of ​​sub-channel 302 perpendicular to the length direction X is S. The capacity of the battery cell 300 is C, and the thickness is 0.05 mm. 2 / Ah≤S / C≤0.7mm 2 / Ah. The capacity C of the battery cell 300 ranges from 5Ah to 250Ah. The inner surface of the end cap 323 is provided with a separator 325, and the separator 325 has a vent 3251 along the width direction Z. The cross-sectional area of ​​the vent 3251 along the width direction Z is greater than or equal to the cross-sectional area of ​​the sub-channel 302 along the length direction X.

[0192] With the above structure, gas generated by thermal runaway at any location on the electrode assembly 31 is discharged to channel 301, and the minimum path from channel 301 along its extension direction to the pressure relief section 351 is less than or equal to 550 mm. This short exhaust path facilitates the discharge of gas generated by thermal runaway, ensuring smooth exhaust and improving the safety of the battery cell 300. Setting W1-W2 to the range of 0.01 mm to 8.75 mm allows for good exhaust in the sub-channel 302, resulting in a larger Z-area of ​​the electrode assembly 31 in the housing 32 along the width direction, thus increasing the volumetric energy density. This allows the sub-channel 302 to discharge gas generated by thermal runaway from the electrode assembly 31 more quickly and effectively, improving the safety of the battery cell 300. The ratio of the cross-sectional area of ​​the sub-channel 302 to the battery cell 300 is within the range of mm. 2 / Ah≤S / C≤0.7mm 2 / Ah, and keep the capacity of the battery cell 300 in the range of 5Ah-250Ah, so that the gas generated by the thermal runaway of the electrode assembly 31 can flow to the pressure relief section 351 in a timely and efficient manner to discharge the gas generated by the thermal runaway of the electrode assembly 31 and improve the safety of the battery cell 300.

[0193] According to some embodiments of this application, this application also provides a battery device, including a battery cell 300 as described in the above embodiments.

[0194] According to some embodiments of this application, this application also provides an electrical device, including a battery cell 300 as described in the above embodiments or a battery device as described in the above embodiments, wherein the battery cell 300 or the battery device is used to store or provide electrical energy.

[0195] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and not to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application, and they should all be covered within the scope of the claims and specification of this application. In particular, as long as there is no structural conflict, the various technical features mentioned in the embodiments can be combined in any way. This application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

A battery cell, characterized in that, include: The outer shell has a length direction, a width direction and a thickness direction, the length of the outer shell is greater than or equal to the width of the outer shell, the width of the outer shell is greater than or equal to the thickness of the outer shell, the outer shell includes two first sidewalls located at opposite ends in the thickness direction and a peripheral sidewall connected between the two first sidewalls, the peripheral sidewall being connected to the two first sidewalls on both sides along the thickness direction respectively; An electrode assembly is disposed in the housing. The electrode assembly includes a main body, an electrode tab is provided at the end of the main body along the length direction, and a channel is provided between the main body and the peripheral sidewall. The peripheral sidewall is provided with a pressure relief mechanism, which includes a pressure relief part that is connected to the channel. The shortest path from any position of the channel along the extension direction of the channel to the pressure relief part is less than or equal to 550 mm. The battery cell as described in claim 1, characterized in that, The peripheral sidewall includes two second sidewalls located at opposite ends in the width direction, the distance between the two second sidewalls is W1, and the dimension of the electrode assembly along the width direction is W2, 0.01mm≤W1-W2≤8.75mm. The battery cell as described in any one of claims 1-2 is characterized in that, The channel includes sub-channels extending along the length direction, the sub-channels having a cross-sectional area S perpendicular to the length direction, the battery cell having a capacity C, and 0.05 mm². 2 / Ah≤S / C≤0.7mm 2 / Ah. The battery cell as described in claim 3, characterized in that, The sub-channel has a first dimension L01 along the thickness direction and a second dimension L02 along the width direction, S = L01 * L02, the dimension of L01 ranges from 15mm to 80mm, and the dimension of L02 ranges from 1mm to 10mm. The battery cell as described in claim 3, characterized in that, The capacity C of the battery cell ranges from 5Ah to 250Ah. The battery cell as described in any one of claims 1-5 is characterized in that, The outer casing includes a housing and an end cap. The housing has an opening at one end along its length, and the end cap covers the opening. The inner surface of the end cap has an isolation element, and the isolation element has a vent hole along its width. The battery cell as described in claim 6, characterized in that, The channel includes a sub-channel extending along the length direction, and the sub-channel is in communication with the vent. The battery cell as described in claim 7, characterized in that, The cross-sectional area of ​​the vent along the direction perpendicular to the width is greater than or equal to the cross-sectional area of ​​the sub-channel along the direction perpendicular to the length. The battery cell as described in any one of claims 1-8 is characterized in that, The outer shell is made of aluminum, steel, or titanium. The battery cell as described in any one of claims 1-9 is characterized in that, The outer casing has a length range of 100mm-300mm; and / or, a width range of 60mm-150mm; and / or, a thickness range of 15mm-80mm. The battery cell as described in any one of claims 1-10 is characterized in that, The pressure relief mechanism is provided on at least one side of the peripheral sidewall along the width direction. A battery device, characterized in that, Includes the battery cell as described in any one of claims 1-11. An electrical device, characterized in that, Includes a battery cell as described in any one of claims 1-11 or a battery device as described in claim 12, wherein the battery cell or the battery device is used to store or provide electrical energy.

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