Battery monomer, battery and electric device

Abstract

The embodiment of the utility model provides a battery monomer, a battery and a power utilization device, and the battery monomer comprises a shell (1) which comprises a first wall (12), and the first wall (12) is provided with a pressure relief component (2); an electrode terminal (6) insulated from the housing (1); the electrode assembly (3) is arranged in the shell (1), the electrode assembly (3) comprises an electrode main body (31) and a first tab (32), and the first tab (32) is led out from one end of the electrode main body (31); and the first current collecting piece (4) is configured to electrically connect the first tab (32) with the shell (1), at least part of the first current collecting piece (4) is located between the first tab (32) and the pressure relief component (2), at least one ventilation part (41) and at least one guide part (42) are arranged on the first current collecting piece (4), the ventilation part (41) penetrates through the first current collecting piece (4) in the thickness direction of the first wall (12), and the guide part (42) is arranged in the peripheral area of the ventilation part (41).

Description

Technical Field

[0001] This application relates to the technical field of batteries, and particularly to a battery cell, a battery, and an electrical device. Background Art

[0002] In recent years, new energy vehicles have achieved leapfrog development. In the field of electric vehicles, power batteries, as the power source of electric vehicles, play an irreplaceable role. With the strong promotion of new energy vehicles, the demand for power battery products is also increasing day by day. As the core component of new energy vehicles, batteries have high requirements for use safety.

[0003] However, how to improve the safety of batteries during use has always been a difficult problem in the industry. Summary of the Utility Model

[0004] The purpose of this application is to improve the working safety of batteries.

[0005] According to the first aspect of this application, a battery cell is provided, including:

[0006] A housing, including a first wall, and the first wall is provided with a pressure relief component;

[0007] An electrode terminal, which is insulated and arranged on the housing;

[0008] An electrode assembly, arranged inside the housing, the electrode assembly includes an electrode body and a first tab, and the first tab extends from one end of the electrode body; and

[0009] A first current collector, configured to electrically connect the first tab and the housing, and at least part of the first current collector is located between the first tab and the pressure relief component. At least one ventilation portion and at least one guiding portion are provided on the first current collector. The ventilation portion penetrates the first current collector along the thickness direction of the first wall, and the guiding portion is arranged in the outer peripheral area of the ventilation portion.

[0010] In this embodiment, by providing a ventilation portion and a guiding portion on the first current collector close to the pressure relief component, during pressure relief, the guiding portion weakens the structural strength of the first current collector. When the air pressure is relatively high, it can guide the first current collector to crack along a preset path to deform or break, increasing the exhaust area. The ventilation portion and the guiding portion can exhaust gas simultaneously, increasing the ventilation area for the gas in the electrode assembly to reach the pressure relief component, preventing blockage during pressure relief, enabling the gas to reach the pressure relief component more smoothly to be discharged outside the battery cell, balancing the air pressure inside and outside the battery cell, and discharging heat in a timely manner, thereby improving the safety of the battery cell during use.

[0011] In some embodiments, the guiding portion includes at least one of a through hole or a notch.

[0012] In this embodiment, the guiding part is set as a through hole. In the case of thermal runaway, gas can more easily enter the through hole directly from the venting part, so as to quickly diffuse to the surrounding area, which is beneficial to improving the exhaust speed. The through hole can also play a full role when the internal air pressure of the battery cell is relatively small, enabling the gas to reach the pressure relief component more smoothly and be discharged, so that the internal and external air pressures of the battery cell are balanced, thereby improving the safety during the use of the battery cell.

[0013] Alternatively, the guiding part is set as a notch, which can reduce the weakening of the strength of the first current collector, facilitating the guarantee of the strength of the first current collector. And in the case of thermal runaway, a strength-weakened area is formed at the notch, and the first current collector can crack along the notch, or further deform at the notch. For example, the two sides of the notch are at different heights, which can effectively increase the exhaust area, enabling the gas to reach the pressure relief component more smoothly and be discharged, so that the internal and external air pressures of the battery cell are balanced, thereby improving the safety during the use of the battery cell.

[0014] In some embodiments, the guiding part extends along the radial direction of the first current collector.

[0015] In this embodiment, the guiding part extends along the radial direction of the first current collector, which is beneficial to guiding the gas from the central area of the first current collector to the periphery, quickly evacuating the gas to prevent aggregation, reducing the gas pressure near the venting part, and increasing the exhaust speed, enabling the gas to reach the pressure relief component more smoothly to be discharged outside the battery cell, so that the internal and external air pressures of the battery cell are balanced, thereby improving the safety during the use of the battery cell.

[0016] Moreover, for a wound electrode assembly, the first tab is a multi-layer structure. To ensure reliable welding of each layer of tab, at least part of the weld marks are arranged along the radial direction, and such a guiding part facilitates the setting of weld marks on the first current collector.

[0017] In some embodiments, at least one guiding part includes a first guiding part, and the first end of the first guiding part close to the venting part is communicated with the venting part.

[0018] In this embodiment, after the gas reaches the venting part from the central hole of the electrode assembly, the gas directly acts on the first end of the guiding part, which is beneficial to deforming or cracking the first current collector under the guidance of the guiding part. The gas directly enters the guiding part along the communication position between the guiding part and the venting part, basically realizing simultaneous exhaust of the venting part and the guiding part communicated with it, and can improve the exhaust speed.

[0019] In some embodiments, two first guiding parts are located on the same straight line, and the first ends of the two first guiding parts close to the venting part are both communicated with the venting part.

[0020] In this embodiment, the two first guiding parts are located on the same straight line. After the gas reaches the ventilation part from the central hole of the electrode assembly, the areas for exhausting gas by deformation or cracking on the first current collector are made symmetrical, so that the gas distribution along the circumference of the first current collector is balanced, preventing gas from accumulating on the same side and causing pressure to rise, enabling the gas to reach the pressure relief component more smoothly and be discharged, and balancing the air pressure inside and outside the battery cell.

[0021] In some embodiments, at least one guiding part includes a second guiding part, and a preset spacing part is provided between the first end of the second guiding part close to the ventilation part and the side wall of the ventilation part.

[0022] Based on the setting of the guiding part to increase the exhaust area, this embodiment is conducive to improving the structural strength of the first current collector by providing a preset spacing part between the second guiding part and the ventilation part.

[0023] In some embodiments, the two second guiding parts are located on the same straight line, and a preset spacing part is provided between the first ends of the two second guiding parts and the side wall of the ventilation part.

[0024] In this embodiment, the two second guiding parts are located on the same straight line, and preset spacing parts are provided at positions opposite to the ventilation part, which can improve the structural symmetry of the first current collector, make its strength distribution more balanced, be conducive to ensuring the structural strength of the first current collector during the normal operation of the battery cell, and improve the reliability of the electrical connection between the first current collector and the first tab.

[0025] In some embodiments, the preset spacing part is configured to be damaged when the air pressure in the outer shell exceeds a preset threshold.

[0026] The second guiding part of this embodiment is conducive to ensuring the structural strength of the first current collector during the normal operation of the battery cell, and can also cause the preset spacing part to be damaged when the battery cell undergoes thermal runaway, enabling the gas to more easily reach the second guiding part from the ventilation part, thereby increasing the exhaust area and facilitating the smooth discharge of the internal gas.

[0027] In some embodiments, the length of the preset spacing part is less than 15 mm, and the thickness of the preset spacing part is less than 2 mm.

[0028] By limiting the length and thickness of the preset spacing part, this embodiment can ensure that it reliably cracks when the battery cell undergoes thermal runaway. After the gas reaches the ventilation part from the central hole of the electrode assembly, it can smoothly enter the second guiding part, thereby increasing the ventilation area, enabling the gas to reach the pressure relief component more quickly and be discharged, balancing the air pressure inside and outside the battery cell, and improving the safety of the battery cell during thermal runaway.

[0029] In some embodiments, multiple guiding parts are arranged at intervals along the circumference of the first current collector.

[0030] In this embodiment, a plurality of guiding portions are circumferentially spaced on the first current collector, which can improve the uniformity of gas discharge in the entire circumference of the first current collector, make full use of exhaust at different circumferential positions, increase the exhaust speed, and enable the gas to reach the pressure relief component more smoothly to discharge outside the battery cell.

[0031] In some embodiments, the plurality of guiding portions are arranged centrosymmetrically with respect to the center of the first current collector.

[0032] This embodiment can make the distribution of the plurality of guiding portions on the first current collector more uniform, which can not only make the structural strength of each part of the first current collector uniform, but also make the exhaust area distribution uniform, while ensuring the reliability of the electrical connection between the first current collector and the first tab and the exhaust uniformity.

[0033] In some embodiments, the distance between the second ends of two guiding portions located on the same straight line, each away from the vent portion, is L, and the maximum radial dimension of the first current collector is D, where L = 0.1D to 0.8D.

[0034] This embodiment designs the length of the guiding portion according to the diameter of the first current collector, so that the guiding portion can not only meet the exhaust speed requirement, but also ensure the structural strength of the first current collector.

[0035] In some embodiments, the thickness of the region of the first current collector where the guiding portion is provided is, and the width of the guiding portion is W, where W = T to 5T.

[0036] This embodiment designs the width of the guiding portion according to the thickness of the region of the first current collector where the guiding portion is provided, so that the width of the guiding portion is not less than the thickness, which can ensure that the guiding portion is easily cracked during pressure relief and effectively increase the ventilation area, and the width of the guiding portion is not greater than 5 times the thickness, which can ensure the structural strength of the first current collector.

[0037] In some embodiments, the first current collector is provided with a positioning hole at the second end away from the vent portion.

[0038] In this embodiment, by providing the positioning hole, not only can the exhaust area be further increased, but also it plays a positioning role during the stacking process after the first current collector is processed, preventing deflection. During the assembly process of the battery cell, when the automated picking device acquires the first current collector and places it on the end of the first tab, for example, by sucking the first current collector with a negative pressure suction nozzle, the guiding portions of each first current collector can be in the same circumferential position. Thus, each battery cell can weld the first current collector and the first tab according to the preset welding trajectory without readjusting the welding trajectory, which can improve the assembly efficiency of the battery cell.

[0039] Moreover, positioning through the positioning holes can improve the positioning accuracy because, compared with the method of positioning through the outer periphery of the first current collector, the positioning holes are smaller in size, making it easier to ensure machining accuracy. In addition, by arranging the positioning holes at the second end of the guiding portion, which is farther from the center, the positioning effect can be improved.

[0040] In some embodiments, at least one guiding portion includes a plurality of guiding portions extending radially along the first current collector, and two of the plurality of guiding portions are located on the same straight line. There are two positioning holes, which are respectively arranged at the second ends of the two guiding portions on the same straight line.

[0041] In this embodiment, positioning holes are only arranged at the second ends of the two guiding portions on the same straight line, which can create a difference between the plurality of guiding portions, thereby better playing a positioning role and preventing deflection. Moreover, it can also reduce the weakening effect of arranging the positioning holes on the strength of the first current collector.

[0042] In some embodiments, the positioning hole is a circular hole, the thickness of the region of the first current collector where the guiding portion is arranged is T, and the diameter of the circular hole is d, where d = 4T - 10T.

[0043] In this embodiment, the diameter of the positioning hole is designed according to the thickness of the region of the first current collector where the guiding portion is arranged, such that the diameter of the positioning hole is not less than 4 times the thickness of the first current collector to ensure that the size of the positioning hole is convenient for positioning, and the diameter of the positioning hole is not greater than 10 times the thickness of the first current collector to ensure the structural strength of the first current collector 4.

[0044] In some embodiments, the ventilation portion is polygonal, and the first end of the guiding portion close to the ventilation portion is aligned with the corner region of the ventilation portion.

[0045] In this embodiment, when the battery cell undergoes thermal runaway and releases internal gas, the acting force on the first current collector can cause stress concentration in the corner region of the ventilation portion, so as to tear the first current collector from the corner of the ventilation portion. By aligning the first end of the guiding portion close to the ventilation portion with the corner region of the ventilation portion, the acting force generated by cracking the corner region can be further transmitted to the first end of the guiding portion, causing the first current collector to deform or crack in the guiding portion region, increasing the ventilation area of the first current collector during thermal runaway, reducing the blockage of gas, improving the exhaust smoothness and exhaust efficiency, reducing the risks such as fire and explosion caused by unsmooth pressure relief of the battery cell, and improving the safety of using the battery cell.

[0046] In some embodiments, there are a plurality of guiding portions, and the number of guiding portions is the same as the number of corners of the polygon, and the plurality of guiding portions are arranged in one-to-one correspondence with the plurality of corners of the polygon.

[0047] In this embodiment, a guiding portion is provided at a position corresponding to each fold angle of the ventilation portion, which can make full use of the stress concentration generated at each fold angle to further deform or crack the first current collector along the guiding portion, and increase the ventilation area of the first current collector during thermal runaway as much as possible, making the exhaust smoother.

[0048] In some embodiments, the first current collector includes a housing connection portion and a tab connection portion made of different base materials. The housing connection portion has the same base material as the first wall, and the tab connection portion has the same base material as the first tab. The ventilation portion and the guiding portion are provided on the tab connection portion.

[0049] After welding the first wall and the first current collector in this embodiment, since the difference in the thermal expansion coefficients of the materials of the housing connection portion and the first wall does not exceed a preset threshold, it is easy to generate welding cracks due to the inconsistent shrinkage of the two materials during cooling, which can prevent liquid leakage problems and improve the reliability of the battery cell operation.

[0050] In some embodiments, the tab connection portion is welded to the first tab to form a welding mark, and the welding mark and the guiding portion are arranged at intervals in the circumferential direction.

[0051] In this embodiment, the welding mark and the guiding portion are arranged at intervals in the circumferential direction, which can prevent the heat generated during the welding process from damaging the guiding portion to ensure the structural strength of the first current collector during normal use.

[0052] In some embodiments, the ventilation portion is provided in the central region of the first current collector.

[0053] In this embodiment, the ventilation portion is provided in the central region of the first current collector, which can enable some of the gas discharged along the central hole of the electrode assembly to directly pass through the ventilation portion to reach the pressure relief component, reducing the pressure relief resistance during thermal runaway of the battery cell and improving the exhaust efficiency. Moreover, the ventilation portion provided in the central region is conducive to causing the guiding portion located in the outer peripheral region to crack and deform or break when discharging gas, so that the ventilation portion and the guiding portion jointly achieve a better pressure relief effect. In some embodiments, the housing includes a shell and an end cap. The shell has an opening, and the end cap closes the opening. The first wall is the end cap or the bottom wall of the shell.

[0054] In this embodiment, the shell and the end cap are connected to form the housing, which can facilitate the installation of the internal structure.

[0055] In some embodiments, the first wall is the end cap, and an electrode terminal is provided on the bottom wall. The electrode terminal is insulated from the bottom wall; the electrode assembly further includes a second tab, the second tab is led out from the other end of the electrode body, the second tab has the opposite polarity to the first tab, and the battery cell further includes a second current collector configured to electrically connect the second tab and the electrode terminal.

[0056] The battery cell of this embodiment has the electrode terminal located at one end far from the pressure relief component. When thermal runaway occurs, the discharged substances will spray out from the end where the pressure relief component is located, far from the electrode terminal, and thus far from the bus bar used to electrically connect multiple battery cells, which can reduce the impact on the electrical connection of the battery cells during thermal runaway.

[0057] According to the second aspect of the present application, a battery is provided, including the battery cell of the above embodiment.

[0058] According to the third aspect of the present application, an electrical device is provided, including the battery cell and / or battery of the above embodiment, for providing electrical energy for the electrical device. Description of the Drawings

[0059] To more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments of the present application will be briefly introduced below. Obviously, the following described drawings are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained according to the drawings without creative efforts.

[0060] Figure 1 It is a schematic structural diagram of some embodiments of installing the battery in a vehicle according to the present application.

[0061] Figure 2 It is an exploded view of the first embodiment of the battery according to the present application.

[0062] Figure 3 It is an exploded view of some embodiments of the battery cell according to the present application.

[0063] Figure 4 It is a front view of some embodiments of the first current collector in the battery cell according to the present application.

[0064] Figure 5 It is Figure 4 A - A cross-sectional view of

[0065] Figure 6 It is Figure 4 A schematic structural diagram of a variant of

[0066] Figure 7 It is Figure 4 A schematic structural diagram of another variant of

[0067] In the drawings, the drawings are not drawn to actual scale.

[0068] Marking Explanation:

[0069] 100. Battery cell;

[0070] 1. Outer shell; 10. Housing; 11. Side wall; 12. First wall; 12'. End cap; 13. Bottom wall;

[0071] 2. Pressure relief component;

[0072] 3. Electrode assembly; 31. Electrode body; 32. First tab; 33. Second tab; 34. Central hole;

[0073] 4. First current collector; 41. Ventilation part; 42. Guide part; 421. First guide part; 422. Second guide part; 42A. Through hole; 42B. Notch; 423. Preset spacing part; 424. Positioning hole; 43. Tab connection part; 44. Outer shell connection part;

[0074] 5. Second current collector;

[0075] 6. Electrode terminal;

[0076] 200. Battery; 201. Box assembly; 201A. Box; 201B. First cover; 201C. Second cover;

[0077] 300. Vehicle; 301. Axle; 302. Wheel; 303. Motor; 304. Controller. Detailed implementation manners

[0078] The following further describes the implementation manners of the present application in detail in conjunction with the drawings and embodiments. The following detailed description of the embodiments and the drawings are used to exemplarily illustrate the principle of the present application, but cannot be used to limit the scope of the present application, that is, the present application is not limited to the described embodiments.

[0079] In the description of the embodiments of the present application, the term "plural" refers to two or more (including two). Similarly, "multiple groups" refers to two or more groups (including two groups), and "multiple pieces" refers to two or more pieces (including two pieces).

[0080] The present application uses descriptions of orientation or positional relationships indicated by "upper", "lower", "top", "bottom", "front", "rear", "inner" and "outer", etc. This is only for the convenience of describing the present application, rather than indicating or implying that the device referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the protection scope of the present application.

[0081] In addition, the terms "first", "second", "third", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance. "Vertical" is not strictly vertical, but within the allowable error range. "Parallel" is not strictly parallel, but within the allowable error range. The orientation words appearing in the following description are all the directions shown in the drawings and do not limit the specific structure of the present application.

[0082] In the description of the present application, it should also be noted that, unless otherwise clearly specified and defined, the terms "installed", "connected", and "coupled" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected, or indirectly connected through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific circumstances.

[0083] Reference to "an embodiment" herein means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least some embodiments of the present application. The phrase appears in various places in the specification and does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive of other embodiments. Those skilled in the art will explicitly and implicitly understand that the embodiments described herein can be combined with other embodiments.

[0084] Current battery cells generally include a housing and an electrode assembly accommodated within the housing, and an electrolyte is filled within the housing. The electrode assembly is mainly formed by laminating or winding a first electrode tab and a second electrode tab with opposite polarities, and an insulating member, such as a separator, is usually provided between the first electrode tab and the second electrode tab. The portions of the first electrode tab and the second electrode tab coated with the active material constitute the main body of the electrode assembly, and the portions of the first electrode tab and the second electrode tab not coated with the active material respectively constitute a first electrode ear and a second electrode ear. In the battery cell, the first electrode tab may be a positive electrode tab, including a positive current collector and positive active material layers provided on both sides of the positive current collector. The positive current collector may be a metal foil or a composite current collector. For example, as the metal foil, aluminum or stainless steel with a silver surface treatment, stainless steel, copper, aluminum, nickel, carbon electrode, carbon, nickel, or titanium, etc. may be used. The composite current collector may include a polymer material base layer and a metal layer. The composite current collector may be formed by forming a metal material (such as aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy, etc.) on a polymer material substrate (such as substrates of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.). The positive active material layer may include at least one of the following materials: lithium-containing phosphate, lithium transition metal oxide, and their respective modified compounds. However, the present application is not limited to these materials, and other conventional materials that can be used as battery positive active materials may also be used. These positive active materials may be used alone or in combination of two or more. The second electrode tab may be a negative electrode tab, including a negative current collector and negative active material layers provided on both sides of the negative current collector. The negative current collector may be a metal foil or a composite current collector. For example, as the metal foil, aluminum or stainless steel with a silver surface treatment, stainless steel, copper, aluminum, nickel, carbon electrode, carbon, nickel, or titanium, etc. may be used. The composite current collector may include a polymer material base layer and a metal layer. The composite current collector may be formed by forming a metal material (such as copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy, etc.) on a polymer material substrate (such as substrates of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.). The negative active material layer may use negative active materials for batteries well-known in the art. As an example, the negative 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. Optionally, the first electrode tab may also be a negative electrode tab, and correspondingly, the second electrode tab is a positive electrode tab. The first electrode ear and the second electrode ear may be located together at one end of the main body or separately at both ends of the main body. During the charging and discharging process of the battery cell, the positive active material and the negative active material react with the electrolyte, and the electrode ears are connected to the electrode terminals to form a current loop.

[0085] At present, during the use of cylindrical battery cells, problems with relatively poor safety still occur. Through research, it is found that the main reason for the relatively poor safety of battery cells is that after thermal runaway occurs, the high-temperature flue gas and active substances generated in the electrode assembly will flow towards the pressure relief component through the through-hole in the center of the current collector, and be discharged through the pressure relief component at the end of the outer casing. However, due to the relatively small through-hole in the center of the current collector, when the internal pressure of the battery cell is too high, it will cause poor exhaust, and a relatively high pressure will accumulate inside the battery cell and cannot be relieved in time, thus affecting the safety of the battery cell during operation.

[0086] Based on the disadvantages of the above solutions, the present application proposes a battery cell, including: an outer casing, including a first wall, and the first wall is provided with a pressure relief component; an electrode terminal, insulated and disposed on the outer casing; an electrode assembly, disposed inside the outer casing, the electrode assembly includes an electrode body and a first tab, and the first tab extends from one end of the electrode body; and a first current collector, configured to electrically connect the first tab and the outer casing, and at least part of the first current collector is located between the first tab and the pressure relief component, and at least one ventilation portion and at least one guiding portion are provided on the first current collector, the ventilation portion penetrates the first current collector along the thickness direction of the first wall, and the guiding portion is disposed in the outer peripheral region of the ventilation portion.

[0087] In the battery cell of this embodiment, by providing a ventilation portion and a guiding portion on the first current collector close to the pressure relief component, during pressure relief, the guiding portion weakens the structural strength of the first current collector. When the air pressure is relatively high, it can guide the first current collector to crack and deform or break along a preset path, increasing the exhaust area. The ventilation portion and the guiding portion can exhaust simultaneously, increasing the ventilation area for the gas in the electrode assembly to reach the pressure relief component, preventing blockage during pressure relief, enabling the gas to reach the pressure relief component more smoothly to be discharged outside the battery cell, balancing the internal and external air pressures of the battery cell, and discharging heat in time, thereby improving the safety during the use of the battery cell.

[0088] The battery cell of the embodiment of the present application is applicable to batteries and electrical devices using such battery cells, and the battery is also applicable to electrical devices.

[0089] The battery of the embodiment of the present application can be used in electrical devices. The electrical device can be an electric vehicle, an electric car, a ship, a spacecraft, etc. For example, the spacecraft includes an airplane, a rocket, a space shuttle, a spaceship, etc.

[0090] Such as Figure 1As shown, the electrical device can be a vehicle 300, such as a new energy vehicle. The new energy vehicle can be a pure electric vehicle, a hybrid vehicle, an extended-range vehicle, etc.; or the electrical device can also be a drone or a ship, etc. Specifically, the vehicle 300 can include an axle 301, wheels 302 connected to the axle 301, a motor 303, a controller 304, and a battery 200. The motor 303 is used to drive the axle 301 to rotate, the controller 304 is used to control the operation of the motor 303, and the battery 200 can be arranged at the bottom, head, or tail of the vehicle 300 to provide electrical energy for the operation of the motor 303 and other components in the vehicle.

[0091] As Figure 2 shown, the battery 200 includes a box body assembly 201 and battery cells 100. In the battery 200, the number of battery cells 100 can be one or more. If there are multiple battery cells 100, the multiple battery cells 100 can be connected in series, parallel, or in a combination of series and parallel. A combination of series and parallel means that there are both series and parallel connections among the multiple battery cells 100. It can be that multiple battery cells 100 are first connected in series, parallel, or in a combination of series and parallel to form a battery module, and then multiple battery modules are connected in series, parallel, or in a combination of series and parallel to form a whole and are accommodated in the box body assembly 201. It can also be that all the battery cells 100 are directly connected in series, parallel, or in a combination of series and parallel together, and then the whole formed by all the battery cells 100 is accommodated in the box body assembly 201.

[0092] Among them, the box body assembly 201 can be either a part of the battery pack and is detachably installed on the electrical device; or the box body assembly 201 can also be a space formed by a structural member in the electrical device for accommodating the battery cells 100. For example, when the battery cells 100 are used in the vehicle 300, the box body assembly 201 is a space formed by the vehicle frame for accommodating the battery cells 100.

[0093] The interior of the box body assembly 201 is hollow for accommodating one or more battery cells 100. According to the shape, quantity, combination method, and other requirements of the accommodated battery cells 100, the box body assembly 201 can also have different shapes and sizes. For example, the box body assembly 201 can include: a box body 201A, a first cover 201B, and a second cover 201C. Both ends of the box body 201A have openings, and the first cover 201B and the second cover 201C are used to close the openings at both ends of the box body 201A. Figure 2 Among them, according to the arrangement of multiple battery cells 100, the box body 201A has a rectangular cylindrical structure. To facilitate the maintenance of the battery 200, the box body assembly 201 is detachably installed on the electrical device.

[0094] The battery cell 100 can be a secondary battery, which means that after the battery cell 100 discharges, it can be activated by charging and continue to be used.

[0095] The battery cell 100 can be a lithium-ion battery, a sodium-ion battery, a sodium-lithium-ion battery, a lithium metal battery, a sodium metal battery, a lithium-sulfur battery, a magnesium-ion battery, a nickel-metal hydride battery, a nickel-cadmium battery, a lead-acid battery, etc., and the embodiments of the present application are not limited thereto.

[0096] As an example, the battery cell 100 can be a cylindrical battery cell, a prismatic battery cell, a pouch battery cell or a battery cell of other shapes. The prismatic battery cell includes a square shell battery cell, a blade-shaped battery cell, a multi-prismatic battery, and the multi-prismatic battery is, for example, a hexagonal prism battery, etc., and the present application has no special limitation.

[0097] In the following description, the cylindrical battery cell 100 is taken as an example for illustration, but it is also applicable to battery cells of other shapes. A plurality of battery cells 100 can be arranged in the xoy plane perpendicular to the first direction z, and a plurality of battery cells 100 can be arranged in a rectangular array along the second direction x and the third direction y, and the second direction x is perpendicular to the third direction y.

[0098] Figure 3 It is an exploded view of some embodiments of the battery cell of the present application. Figure 4 It is a schematic structural diagram of some embodiments of the first current collector. In some embodiments, the battery cell 100 includes: a housing 1 including a first wall 12, and a pressure relief member 2 is provided on the first wall 12; an electrode terminal 6 is insulatingly provided on the housing 1; an electrode assembly 3 is provided in the housing 1, the electrode assembly 3 includes an electrode main body 31 and a first tab 32, and the first tab 32 extends from one end of the electrode main body 31; and a first current collector 4 configured to electrically connect the first tab 32 and the housing 1, and at least a part of the first current collector 4 is located between the first tab 32 and the pressure relief member 2. At least one ventilation portion 41 and at least one guiding portion 42 are provided on the first current collector 4. The ventilation portion 41 penetrates the first current collector 4 along the thickness direction of the first wall 12, and the guiding portion 42 is provided in the outer peripheral region of the ventilation portion 41.

[0099] Among them, the housing 1 adopts a thin-walled hollow structure for accommodating the electrode assembly 3 and the electrolyte. The housing 1 can be a steel shell, an aluminum shell, a composite metal shell (such as a copper-aluminum composite shell) or an aluminum plastic film, etc. The housing 1 can be cylindrical, including a first wall 12, a second wall and a side wall 11. The first wall 12 and the second wall are oppositely arranged, and the side wall 11 is connected between the first wall 12 and the second wall.

[0100] The pressure relief member 2 is provided on the first wall 12. The pressure relief member 2 and the first wall 12 can be integrally formed. For example, a notch is provided on the inner surface or the outer surface of the first wall 12 to form the pressure relief member 2; or the pressure relief member 2 and the first wall 12 adopt a split structure, and the pressure relief member 2 is pre-processed separately and then fixed to the first wall 12 by welding or other means.

[0101] The pressure relief component 2 refers to an element or component that is actuated to release the internal pressure or temperature when the internal pressure or temperature of the battery cell 100 reaches a predetermined threshold. This threshold design varies according to different design requirements. The threshold may depend on one or several of the materials of the positive electrode tab, negative electrode tab, electrolyte, and separator in the battery cell. The pressure relief component 2 can be in the form of, for example, an explosion-proof valve, gas valve, pressure relief valve, or safety valve, and can specifically adopt a pressure-sensitive or temperature-sensitive element or structure, that is, when the internal pressure or temperature of the battery cell 100 reaches a predetermined threshold, the pressure relief component 2 performs an action or a weak structure provided in the pressure relief component 2 is damaged, thereby forming an opening or channel for the release of the internal pressure or temperature of the battery cell 100.

[0102] The "actuation" mentioned here refers to the pressure relief component 2 generating an action or being activated to a certain state, so that the internal pressure and temperature of the battery cell 100 can be released. The actions generated by the pressure relief component 2 can include, but are not limited to: at least a part of the pressure relief component 2 rupturing, breaking, being torn, or opening, etc. When the pressure relief component 2 is actuated, the internal discharge of the battery cell 100 will discharge outward from the actuated part. In this way, the battery cell 100 can be pressure-relieved and temperature-relieved under a controllable pressure or temperature, thereby avoiding potential more serious accidents. The discharges from the battery cell 100 mentioned here include, but are not limited to: electrolyte, dissolved or split positive and negative electrode tabs, fragments of the separator, high-temperature and high-pressure gases generated by the reaction (such as combustible gases such as CH4, CO), flames, etc.

[0103] The electrode assembly 3 is formed by winding a first electrode tab and a second electrode tab with opposite polarities around a winding axis K. The winding axis K is consistent with the first direction z, and usually a separator, such as a diaphragm, is provided between the first electrode tab and the second electrode tab. For a cylindrical battery cell 100, the wound electrode assembly 3 can be cylindrical; for a cuboid-shaped battery cell 100, the wound electrode assembly 3 can be flat.

[0104] The parts of the first electrode tab and the second electrode tab coated with the active material constitute the electrode body 31. The electrode body 31 is provided with a central hole 34 extending along the winding axis K for accommodating the electrolyte or serving as an exhaust channel during pressure relief. The parts of the first electrode tab and the second electrode tab not coated with the active material respectively constitute a first electrode lug 32 and a second electrode lug 33. One of the first electrode lug 32 and the second electrode lug 33 is a negative electrode lug, and the other is a positive electrode lug. The first electrode lug 32 and the second electrode lug 33 are respectively led out from both ends of the electrode body 31.

[0105] The first current collector 4 is configured to electrically connect the first tab 32 and the first wall 12, and the first current collector 4 is located between the first tab 32 and the first wall 12. Herein, the "electrical connection" mentioned can be achieved by welding, such as laser welding. The first current collector 4 can adopt a thin plate structure, for example, a thin plate with a uniform thickness, or there are concave-convex or bent structures in a local area of the thin plate. For the cylindrical battery cell 100, the first current collector 4 can be disc-shaped.

[0106] The first current collector 4 is provided with a vent portion 41 and a guiding portion 42. The vent portion 41 penetrates in the thickness direction of the first current collector 4 and is used to form a channel for the gas in the electrode assembly 3 to be discharged to the pressure relief component 2. The vent portion 41 can be circular, oval, polygonal or other shapes. The vent portion 41 can be one or more.

[0107] The guiding portion 42 is arranged in the outer peripheral area of the vent portion 41. The guiding portion 42 can be arranged at an interval from the vent portion 41 or communicated with the vent portion 41. Its shape can be designed according to the goal of facilitating the gas to reach the pressure relief component 2. The guiding portion 42 is used to make the first current collector 4 form a weakened strength area, so as to guide the first current collector 4 to crack during the pressure relief process to increase the exhaust area and exhaust gas together with the vent portion 41. When a plurality of guiding portions 42 are arranged, they can be evenly distributed on the first current collector 4 to make the strength uniform everywhere and facilitate guiding the gas from the central area to the periphery. For example, the guiding portion 42 can be circular, oval, polygonal or other shapes, or in an elongated shape extending along a straight line or a curve.

[0108] In this embodiment, by providing the vent portion 41 and the guiding portion 42 on the first current collector 4 close to the pressure relief component 2, during pressure relief, the guiding portion 42 weakens the structural strength of the first current collector 4. When the air pressure is relatively high, it can guide the first current collector 4 to crack along a preset path to deform or break, increasing the exhaust area. The vent portion 41 and the guiding portion 42 can exhaust gas at the same time, increasing the ventilation area for the gas in the electrode assembly 3 to reach the pressure relief component 2, preventing blockage during pressure relief, enabling the gas to reach the pressure relief component 2 more smoothly to be discharged outside the battery cell 100, balancing the air pressure inside and outside the battery cell 100, and discharging heat in time, thereby improving the safety of the battery cell 100 during use.

[0109] In some embodiments, the vent portion 41 is arranged in the central area of the first current collector 4.

[0110] Among them, one or more vents 41 are provided in the central area of ​​the first current collector 4, and the vents 41 can be aligned with the central hole 34 of the electrode assembly 3, and the area of ​​at least one vent 41 can be close to the area of ​​the central hole 34. The "central area" mentioned here is not limited to the exact center, for example, the vent 41 deviates from the exact center due to machining errors, or multiple vents 41 are provided, and the multiple vents 41 are distributed in a certain range of the central area, but the exact center is not necessarily provided with a vent 41, such as multiple vents 41 are arranged along annular intervals, or on this basis, a vent 41 is added in the exact center.

[0111] In this embodiment, the vent 41 is arranged in the central area of ​​the first current collector 4, so that part of the gas discharged along the central hole 34 of the electrode assembly 3 can directly pass through the vent 41 to reach the pressure relief component 2, reducing the pressure relief resistance when the battery cell 100 is in thermal runaway, and improving the exhaust efficiency. In addition, the vent 41 arranged in the central area is conducive to causing the guide part 42 located in the peripheral area to crack and deform or damage when the gas is discharged, so that the vent 41 and the guide part 42 can achieve a better pressure relief effect together.

[0112] In some embodiments, Figure 5 As shown, the guide portion 42 includes at least one of a through hole 42A or a notch 42B.

[0113] Among them, Figure 5 As shown, the guide portion 42 includes a through hole 42A, which passes through the first current collecting member 4 in the thickness direction. The through hole 42A is an elongated shape extending in a straight line or a curved trajectory. Extending along a straight line can reduce the resistance during gas flow and facilitate processing. Alternatively, it can be a circular, elliptical, polygonal or other special-shaped structure.

[0114] Setting the guide portion 42 to be elongated has the following advantages: on the basis of guiding the first current collector 4 to split and increase the exhaust area, since the width of the guide portion 42 perpendicular to its extension direction is small, under normal use, it is easier to ensure the structural strength of the first current collector 4, and it is not easy to deform, which can improve the reliability of the electrical connection between the first pole tab 32 and the first current collector 4. Moreover, when the first pole tab 32 and the first current collector 4 are electrically connected by welding, the influence on the welding area can be reduced. If the welding track avoids the guide portion 42, the area and uniformity of the welding track on the end surface of the first pole tab 32 can also be ensured, which can improve the reliability of the electrical connection between the first pole tab 32 and the first current collector 4.

[0115] like Figure 6As shown, the guiding portion 42 includes a notch 42B. The notch 42B can be provided on one side of the first current collector 4 close to the first wall 12 or on one side of the first current collector 4 close to the first tab 32. The notch 42B is provided at a partial thickness of the first current collector 4 and does not penetrate the entire thickness. By providing the notch 42B, a thickness reduction portion is formed. The notch 42B can be an elongated shape extending along a straight or curved trajectory.

[0116] As Figure 7 shown, Figure 5 and Figure 6 the guiding portion 42 of Figure 7 extends along a continuous trajectory. The difference of Figure 7 is that the guiding portion 42 extends along a discontinuous trajectory to form a dotted line. The guiding portion 42 is formed by the through hole 42A or the notch 42B, or is formed by a combination of the through hole 42A and the notch 42B.

[0117] In the same first current collector 4, only one type of guiding portion 42 can be provided, or a combination of two or more types of guiding portions 42 can be provided.

[0118] In this embodiment, the guiding portion 42 is set as the through hole 42A. In the case of thermal runaway, gas can more easily enter the through hole 42A directly from the venting portion 41, so as to quickly diffuse to the surrounding area, which is beneficial to improving the exhaust speed. The through hole 42A can also fully play its role when the internal air pressure of the battery cell 100 is relatively small, enabling the gas to reach the pressure relief component 2 more smoothly and discharged, so that the internal and external air pressures of the battery cell 100 are balanced, thereby improving the safety of the battery cell 100 during use.

[0119] Or the guiding portion 42 is set as the notch 42B, which can reduce the weakening of the strength of the first current collector 4, facilitating the guarantee of the strength of the first current collector 4. And in the case of thermal runaway, a strength weakening area is formed at the notch 42B. The first current collector 4 can crack along the notch 42B, or further deform at the notch 42B. For example, the two sides of the notch 42B are at different heights, which can effectively increase the exhaust area, enable the gas to reach the pressure relief component 2 more smoothly and discharged, so that the internal and external air pressures of the battery cell 100 are balanced, thereby improving the safety of the battery cell 100 during use.

[0120] In some embodiments, as Figure 4 shown, the guiding portion 42 extends along the radial direction of the first current collector 4.

[0121] When multiple guiding portions 42 are provided, the multiple guiding portions 42 can form a radial shape.

[0122] Optionally, the guiding part 42 can also extend along the circumferential direction of the first current collector 4, or extend in other directions. For example, multiple guiding parts 42 all extend along the circumferential direction and are distributed at different radial positions. The guiding parts 42 at adjacent radial positions can be staggeredly arranged, and one or more guiding parts 42 can be arranged at the same radial position.

[0123] In this embodiment, the guiding part 42 extends along the radial direction of the first current collector 4, which is beneficial to guiding the gas from the central region of the first current collector 4 to the periphery, can quickly evacuate the gas to prevent aggregation, can reduce the gas pressure near the gas vent part 41, and increase the exhaust speed, so that the gas can reach the pressure relief component 2 more smoothly to be discharged outside the battery cell 100, and balance the internal and external air pressures of the battery cell 100, thereby improving the safety of the battery cell 100 during use.

[0124] Moreover, for the wound electrode assembly 3, the first tab 32 is a multi-layer structure. In order to ensure reliable welding of each layer of tab, at least part of the welding marks are arranged along the radial direction, and such guiding parts 42 facilitate the arrangement of welding marks on the first current collector 4.

[0125] In some embodiments, as Figure 4 shown, at least one guiding part 42 includes a first guiding part 421, and the first end of the first guiding part 421 close to the gas vent part 41 is communicated with the gas vent part 41.

[0126] Among them, the first end of the guiding part 42 is communicated with the gas vent part 41, and the second end of the guiding part 42 has a preset interval from the outer edge of the first current collector 4.

[0127] In this embodiment, after the gas reaches the gas vent part 41 from the central hole 34 of the electrode assembly 3, the gas directly acts on the first end of the guiding part 42, which is beneficial to deforming or cracking the first current collector 4 under the guidance of the guiding part 42. The gas directly enters the guiding part 42 along the communication position between the guiding part 42 and the gas vent part 41, and basically realizes simultaneous exhaust of the gas vent part 41 and the guiding part 42 communicated with it, which can improve the exhaust speed.

[0128] In some embodiments, two first guiding parts 421 are located on the same straight line, and the first ends of the two first guiding parts 421 close to the gas vent part 41 are both communicated with the gas vent part 41.

[0129] Among them, at least one guiding part 42 can only include two first guiding parts 421 located on the same straight line, or at least one guiding part 42 includes four or six or other even numbers of first guiding parts 421, and each pair of first guiding parts 421 is located on the same straight line.

[0130] In this embodiment, two first guiding parts 421 are located on the same straight line. After the gas reaches the ventilation part 41 from the central hole 34 of the electrode assembly 3, the regions for exhausting gas by deformation or cracking on the first current collector 4 are symmetric, so that the gas distribution along the circumference of the first current collector 4 is balanced, preventing the gas from gathering on the same side and causing pressure increase, enabling the gas to reach the pressure relief component 2 more smoothly for discharge, and balancing the air pressure inside and outside the battery cell 100.

[0131] In some embodiments, as Figure 4 shown, at least one guiding part 42 includes a second guiding part 422. A preset interval part 423 is provided between the first end of the second guiding part 422 close to the ventilation part 41 and the side wall of the ventilation part 41, that is, the first end of the second guiding part 422 is not connected to the ventilation part 41.

[0132] Based on the setting of the guiding part 42 to increase the exhaust area, this embodiment is conducive to improving the structural strength of the first current collector 4 by providing a preset interval part 423 between the second guiding part 422 and the ventilation part 41.

[0133] In some embodiments, two second guiding parts 422 are located on the same straight line, and preset interval parts 423 are provided between the first ends of the two second guiding parts 422 and the side wall of the ventilation part 41.

[0134] Among them, the lengths X of the preset interval parts 423 corresponding to the two second guiding parts 422 located on the same straight line can be the same, forming a symmetric structure, or the two preset interval parts 423 have different lengths X.

[0135] As Figure 4 shown, multiple guiding parts 42 include both first guiding parts 421 and second guiding parts 422 at the same time, and the first guiding parts 421 and the second guiding parts 422 can both extend radially. For example, two first guiding parts 421 and two second guiding parts 422 are arranged at equal intervals along the circumference on the first current collector 4. The ventilation part 41 is square. The first ends of the two first guiding parts 421 are respectively connected to the left and right vertices of the ventilation part 41, and preset interval parts 423 are provided between the first ends of the two second guiding parts 422 and the upper and lower vertices of the ventilation part 41. Thus, the first guiding parts 421 and the second guiding parts 422 are alternately arranged in the circumferential direction, which can make the strength distribution of the first current collector 4 uniform in the circumferential direction.

[0136] In this structure, the first guiding portion 421 among the multiple guiding portions 42 is communicated with the ventilation portion 41. After the gas reaches the ventilation portion 41 from the central hole 34 of the electrode assembly 3, it can directly enter the first guiding portion 421 along the communication position between the guiding portion 42 and the ventilation portion 41, which can improve the exhaust speed. There is a preset interval portion 423 between the first end of the second guiding portion 422 and the side wall of the ventilation portion 41, which is beneficial to ensuring the structural strength of the first current collector 4 when the battery cell 100 is working normally and improving the reliability of the electrical connection between the first current collector 4 and the first pole ear 32. Thus, this structure takes into account both the exhaust speed and the structural strength of the first current collector 4, and can improve the safety and reliability of the battery cell 100 during operation at the same time.

[0137] In this embodiment, the two second guiding portions 422 are located on the same straight line, and preset interval portions 423 are provided at opposite positions of the ventilation portion 41, which can improve the structural symmetry of the first current collector 4, make its strength distribution more balanced, be beneficial to ensuring the structural strength of the first current collector 4 when the battery cell 100 is working normally, and improve the reliability of the electrical connection between the first current collector 4 and the first pole ear 32.

[0138] In some embodiments, the preset interval portion 423 is configured to be damaged when the air pressure in the housing 1 exceeds a preset threshold.

[0139] Among them, in the normal working state of the battery cell 100, the second guiding portion 422 is connected to the ventilation portion 41 through the preset interval portion 423; in the case of thermal runaway, the connecting material between the second guiding portion 422 and the ventilation portion 41 is damaged under the action of gas pressure and high temperature. The "damage" mentioned here may refer to the fracture, torsion or detachment of the preset interval portion 423, etc.

[0140] The second guiding portion 422 of this embodiment is beneficial to ensuring the structural strength of the first current collector 4 when the battery cell 100 is working normally, and can also cause the preset interval portion 423 to be damaged when the battery cell 100 undergoes thermal runaway, making it easier for the gas to reach the second guiding portion 422 from the ventilation portion 41, thereby increasing the exhaust area and facilitating the smooth discharge of the internal gas.

[0141] In some embodiments, the length X of the preset interval portion 423 is less than 15 mm, and the thickness of the preset interval portion 423 is less than 2 mm.

[0142] In this embodiment, by restricting the length X and thickness of the preset spacing portion 423, it can be ensured that it reliably cracks in the case of thermal runaway of the battery cell 100. After the gas reaches the ventilation portion 41 from the central hole 34 of the electrode assembly 3, it can smoothly enter the second guiding portion 422, thereby increasing the ventilation area, enabling the gas to reach the pressure relief component 2 more quickly and be discharged, balancing the internal and external pressures of the battery cell 100, and improving the safety of the battery cell 100 during thermal runaway.

[0143] In some embodiments, there are multiple guiding portions 42, and the multiple guiding portions 42 are arranged at intervals along the circumferential direction of the first current collector 4.

[0144] Among them, the multiple guiding portions 42 are evenly spaced along the circumferential direction of the first current collector 4. The number of the guiding portions 42 is selected to ensure the structural strength of the first current collector 4 under normal use conditions and not affect the reliable electrical connection between the first current collector 4 and the first tab 32, and also ensure that there is sufficient ventilation area for the gas to be discharged smoothly. For example, two, three, four or more guiding portions 42 can be provided.

[0145] For example, the multiple guiding portions 42 all extend along the radial direction and are evenly spaced along the circumferential direction of the first current collector 4, forming a radial shape.

[0146] In this embodiment, multiple guiding portions 42 are arranged at intervals along the circumferential direction of the first current collector 4, which can improve the uniformity of gas discharge in the entire circumferential direction of the first current collector 4, make full use of exhaust at different circumferential positions, increase the exhaust speed, and enable the gas to reach the pressure relief component 2 more smoothly to be discharged outside the battery cell 100.

[0147] In some embodiments, the multiple guiding portions 42 are arranged in central symmetry with respect to the center of the first current collector 4.

[0148] This embodiment can make the distribution of the multiple guiding portions 42 on the first current collector 4 more uniform, which can not only make the structural strength of each part of the first current collector 4 uniform, but also make the distribution of the exhaust area uniform, while ensuring the reliability of the electrical connection between the first current collector 4 and the first tab 32 and the exhaust uniformity.

[0149] In some embodiments, the distance between the second ends of two guiding portions 42 located on the same straight line and away from the ventilation portion 41 is L, and the maximum radial dimension of the first current collector 4 is D, where L = 0.1D to 0.8D.

[0150] This embodiment designs the length of the guiding portion 42 according to the diameter D of the first current collector 4, so that the guiding portion 42 can not only meet the exhaust speed requirements but also ensure the structural strength of the first current collector 4.

[0151] In some embodiments, the thickness of the region where the guiding portion 42 is provided on the first current collector 4 is T, the width of the guiding portion 42 is W, and W = T to 5T.

[0152] Among them, as Figure 5 shown, the first current collector 4 includes a housing connection portion 44 and an ear connection portion 43 stacked in the thickness direction, and the guiding portion 42 is provided on the ear connection portion 43, that is, the thickness of the ear connection portion 43 is T.

[0153] In this embodiment, the width W of the guiding portion 42 is designed according to the thickness T of the region where the guiding portion 42 is provided on the first current collector 4, so that the width W of the guiding portion 42 is not less than the thickness T, which can ensure that the guiding portion 42 is easily cracked during pressure relief and effectively increase the ventilation area. The width W of the guiding portion 42 is not greater than 5 times the thickness T, which can ensure the structural strength of the first current collector 4.

[0154] In some embodiments, as Figure 4 shown, a positioning hole 424 is provided at the second end of the guiding portion 42 away from the ventilation portion 41.

[0155] For example, the positioning hole 424 can be set as a round hole, an oval hole, a polygonal hole, etc. The positioning hole 424 communicates with the second end of the guiding portion 42. The positioning hole 424 plays a positioning role when the first current collectors 4 are stacked. For example, positioning posts can be provided, and the positioning hole 424 passes through the positioning posts each time the first current collectors 4 are stacked.

[0156] In this embodiment, by providing the positioning hole 424, not only can the exhaust area be further increased, but also it plays a positioning role during the stacking process after the first current collectors 4 are processed, preventing deflection. During the assembly process of the battery cell 100, when the automated picking device acquires the first current collector 4 and places it on the end of the first ear 32, for example, the first current collector 4 is sucked by a negative pressure suction nozzle, and the guiding portion 42 of each first current collector 4 can be in the same circumferential position. Thus, each battery cell 100 can weld the first current collector 4 and the first ear 32 according to the pre-set welding trajectory without readjusting the welding trajectory, which can improve the assembly efficiency of the battery cell 100.

[0157] Moreover, by positioning through the positioning hole 424, compared with the method of positioning through the outer periphery of the first current collector 4, since the size of the positioning hole 424 is small, it is easy to ensure the machining accuracy and can improve the positioning accuracy. In addition, by providing the positioning hole 424 at the second end of the guiding portion 42, its distance from the center is far, which can improve the positioning effect.

[0158] In some embodiments, at least one guiding portion 42 includes a plurality of guiding portions 42 extending radially along the first current collector 4. Two of the plurality of guiding portions 42 are located on the same straight line. There are two positioning holes 424, and the two positioning holes 424 are respectively provided at the second ends of the two guiding portions 42 on the same straight line.

[0159] As Figure 4 shown, positioning holes 424 are provided at the second ends of two opposite guiding portions 42, and the second ends of the other two guiding portions 42 are not provided with positioning holes 424.

[0160] In this embodiment, positioning holes 424 are only provided at the second ends of the two guiding portions 42 on the same straight line, which can make a difference between the plurality of guiding portions 42, thereby better playing a positioning role and preventing deflection. Moreover, it can also reduce the influence of setting the positioning holes 424 on the strength of the first current collector 4.

[0161] Optionally, if positioning holes 424 are provided at the second ends of all guiding portions 42, or positioning holes 424 are not required to be provided at the second ends of all guiding portions 42. For such a structure, since there is no positioning structure on the first current collector 4, the picking device includes a base body, a turntable, a photographing component and a driving component. The turntable is rotatably mounted on the base body, and the photographing component and the driving component are both mounted on the base body. During the assembly of the battery cell 100, the photographing component is used to photograph an image of the first current collector 4 to determine the deflection angle of the first current collector 4 relative to the standard angular position, and the driving component is used to drive the turntable to rotate so that the first current collector 4 rotates to the standard angular position. After that, the picking device places the first current collector 4 on the end of the first tab 32. At this time, the battery cell 100 can weld the first current collector 4 and the first tab 32 according to a preset welding track. For example, the picking device can be a wire suction nozzle.

[0162] In some embodiments, the positioning hole 424 is a circular hole. The thickness of the region of the first current collector 4 where the guiding portion 42 is provided is T, and the diameter of the circular hole is d, and d = 4T to 10T.

[0163] In this embodiment, the diameter d of the positioning hole 424 is designed according to the thickness T of the region of the first current collector 4 where the guiding portion 42 is provided, so that the diameter d of the positioning hole 424 is not less than 4 times the thickness T of the first current collector 4, which can ensure that the size of the positioning hole 424 is convenient for positioning, and the diameter d of the positioning hole 424 is not greater than 10 times the thickness T of the first current collector 4, which can ensure the structural strength of the first current collector 4.

[0164] In some embodiments, the ventilation portion 41 is polygonal, and the first end of the guiding portion 42 close to the ventilation portion 41 is aligned with the corner region of the ventilation portion 41.

[0165] The vent portion 41 may be in a triangular shape, a quadrilateral shape, etc. The corner region of the vent portion 41 is formed by the adjacent inner walls of the vent portion 41 , and the corner is convex outward away from the vent portion 41 .

[0166] In this embodiment, when the battery cell 100 has thermal runaway and releases internal gas, the force acting on the first current collector 4 can generate stress concentration in the corner area of ​​the vent portion 41, so as to tear the first current collector 4 from the corner of the vent portion 41, so that the first end of the guide portion 42 close to the vent portion 41 is aligned with the corner area of ​​the vent portion 41, and the force generated by the cracking of the corner area can be further transmitted to the first end of the guide portion 42, so that the first current collector 4 is deformed or cracked in the guide portion 42 area, which can increase the ventilation area of ​​the first current collector 4 during thermal runaway, reduce gas obstruction, improve exhaust smoothness and exhaust efficiency, reduce the risk of fire and explosion of the battery cell 100 due to poor pressure relief, and improve the safety of the battery cell 100.

[0167] In some embodiments, a plurality of guide portions 42 are provided, and the number of guide portions 42 is consistent with the number of corners of the polygon, and the plurality of guide portions 42 are provided in a one-to-one correspondence with the plurality of corners of the polygon.

[0168] like Figure 4 As shown, the vent portion 41 is a quadrilateral, and four guide portions 42 are provided and all extend radially, and the first ends of the four guide portions 42 respectively correspond to the four corners of the quadrilateral one by one.

[0169] This embodiment provides a guide portion 42 at a position corresponding to each corner of the vent portion 41, which can fully utilize the stress concentration effect generated at each corner to cause the first current collecting member 4 to further deform or crack along the guide portion 42, thereby increasing the ventilation area of ​​the first current collecting member 4 during thermal runaway as much as possible and making the exhaust smoother.

[0170] In some embodiments, Figure 5 As shown, the first current collecting member 4 includes a shell connecting portion 44 and a pole tab connecting portion 43 with different base materials. The shell connecting portion 44 is made of the same base material as the first wall 12, the pole tab connecting portion 43 is made of the same base material as the first pole tab 32, and the vent 41 and the guide portion 42 are arranged on the pole tab connecting portion 43.

[0171] Among them, the shell connecting part 44 is connected to the outer periphery of the pole ear connecting part 43, the pole ear connecting part 43 is electrically connected to the first pole ear 32, the shell connecting part 44 is electrically connected to the shell 1, and the difference in thermal expansion coefficient between the material of the shell connecting part 44 and the material of the shell 1 does not exceed a preset threshold; wherein, the ventilation part 41 and the guide part 42 are both arranged on the pole ear connecting part 43.

[0172] For example, the first wall 12 is made of steel, and the first tab 32 is made of copper. If the first current collector 4 is entirely made of copper, after welding the first wall 12 and the first current collector 4, due to the significant difference in the thermal expansion coefficients of the first wall 12 and the first current collector 4, the two materials shrink inconsistently during cooling, which easily generates welding cracks and causes a liquid leakage problem, affecting the reliability of the operation of the battery cell 100.

[0173] In this application, the tab connection portion 43 can be made of copper, and the housing connection portion 44 can be made of at least one of steel and nickel. To prevent rusting, both the tab connection portion 43 and the housing connection portion 44 made of steel can be nickel-plated. In this way, the difference in the thermal expansion coefficients between the tab connection portion and the housing 1 is small, and cracks are not easily generated.

[0174] As Figure 5 shown, the tab connection portion 43 and the housing connection portion 44 can be butt-jointed in the radial direction and fixed by welding. Alternatively, as Figure 5 shown, the tab connection portion 43 and the housing connection portion 44 are stacked in the thickness direction. The tab connection portion 43 is disc-shaped, and the housing connection portion 44 is annular. In the height direction of the battery cell 100, the housing connection portion 44 is located on the side of the tab connection portion 43 close to the pressure relief component 2, and the outer radial end of the housing connection portion 44 extends beyond the outer edge of the tab connection portion 43. The ventilation portion 41 and the guiding portion 42 are both provided on the tab connection portion 43, and the guiding portion 42 is located radially inside the inner edge of the housing connection portion 44. The thicknesses of the tab connection portion 43 and the housing connection portion 44 can be kept consistent, which is convenient for welding.

[0175] In this embodiment, after welding the first wall 12 and the first current collector 4, since the difference in the thermal expansion coefficients between the material of the housing connection portion 44 and the material of the first wall 12 does not exceed the preset threshold, the two materials do not shrink inconsistently during cooling, which easily generates welding cracks, and a liquid leakage problem can be prevented, improving the reliability of the operation of the battery cell 100.

[0176] In some embodiments, the tab connection portion 43 is welded to the first tab 32 to form a weld mark, and the weld mark and the guiding portion 42 are circumferentially spaced apart.

[0177] Among them, the weld mark can be formed by laser welding. For the wound electrode assembly 3, the first tab 32 is a multi-layer tab. To reliably weld each layer of the tab, at least part of the weld mark can extend along the radial direction of the first current collector 4. The first current collector 4 can be provided with a plurality of weld marks circumferentially spaced apart, and the weld mark and the guiding portion 42 are circumferentially spaced apart.

[0178] In this embodiment, the weld mark and the guiding portion 42 are circumferentially spaced apart, which can prevent the heat generated during the welding process from damaging the guiding portion 42, so as to ensure the structural strength of the first current collector 4 during normal use.

[0179] In some embodiments, such as Figure 3 shown, the housing 1 includes a housing body 10 and an end cap 12', the housing body 10 has an opening, the end cap 12' closes the opening, and the first wall 12 is the end cap 12' or the bottom wall 13 of the housing body 10.

[0180] Among them, in Figure 3 , the side wall 11 and the bottom wall 13 can be integrally formed. One end of the side wall 11 away from the bottom wall 13 has an opening, the first wall 12 is the end cap 12', and the end cap 12' is connected to the side wall 11 by means such as welding. The pressure relief component 2 is provided on the end cap 12'. Optionally, the pressure relief component 2 is provided on the bottom wall 13 of the housing body 10.

[0181] In this embodiment, the housing 1 is formed by connecting the housing body 10 and the end cap 12', which facilitates the installation of the internal structure.

[0182] In some embodiments, the first wall 12 is the end cap 12', the bottom wall 13 is provided with an electrode terminal 6, and the electrode terminal 6 is insulated from the bottom wall 13; the electrode assembly 3 further includes a second tab 33, the second tab 33 extends from the other end of the electrode body 31, the second tab 33 has the opposite polarity to the first tab 32, and the battery cell 100 further includes a second current collector 5, and the second current collector 5 is configured to electrically connect the second tab 33 and the electrode terminal 6.

[0183] Among them, the end cap 12' can be used as the first electrode lead-out part, the electrode terminal 6 can protrude from the bottom wall 13, which serves as the second electrode lead-out part, and the first electrode lead-out part and the second electrode lead-out part have opposite polarities. Generally, the electrode terminal 6 is the positive electrode and the end cap 12' is the negative electrode.

[0184] The second current collector 5 is located between the second tab 33 and the electrode terminal 6, that is, the second current collector 5 is located between the second tab 33 and the bottom wall 13. The "electrical connection" mentioned here can be achieved by welding, such as laser welding. The second current collector 5 can also adopt a thin plate structure, for example, a thin plate with a uniform thickness, or there are concavities, convexities or bends and other structures in the local area of the thin plate. For the cylindrical battery cell 100, the second current collector 5 can be disc-shaped.

[0185] In this embodiment of the battery cell 100, the electrode terminal 6 is provided at one end away from the pressure relief component 2. When thermal runaway occurs, the discharged substances will spray out from the end where the pressure relief component 2 is located, away from the electrode terminal 6, and thus away from the bus bar for electrically connecting multiple battery cells 100, which can reduce the impact on the electrical connection of the battery cell 100 during thermal runaway.

[0186] In some specific embodiments, such as Figures 1 to 5As shown, the battery cell 100 includes: a housing 1, an electrode assembly 3, a first current collector 4, a second current collector 5, and electrode terminals. The housing 1 includes a housing body 10 and an end cap 12', and the end cap 12' is used to close the opening of the housing body 10. The housing body 10 includes a side wall 11 and a bottom wall 13, and the bottom wall 13 is located at one end away from the end cap 12'. The end cap 12' serves as the first wall 12, and a pressure relief component 2 is provided thereon; an electrode terminal 6 is provided on the bottom wall 13. The end cap 12' serves as the first electrode lead-out portion, and the electrode terminal 6 serves as the second electrode lead-out portion, and is insulated from the bottom wall 13.

[0187] The electrode assembly 3 is arranged inside the housing 1. The electrode assembly 3 includes an electrode body 31, a first tab 32, and a second tab 33. The first tab 32 and the second tab 33 are respectively led out from both ends of the electrode body 31. The first current collector 4 is configured to electrically connect the first tab 32 and the first wall 12, and the first current collector 4 is located between the first tab 32 and the first wall 12; the second current collector 5 is configured to electrically connect the second tab 33 and the electrode terminal 6, and the second current collector 5 is located between the second tab 33 and the bottom wall 13.

[0188] The first current collector 4 includes a tab connection portion 43 and a housing connection portion 44 that are stacked in the thickness direction. The tab connection portion 43 is disc-shaped, and the housing connection portion 44 is annular. The housing connection portion 44 is located on the side of the tab connection portion 43 close to the pressure relief component 2, and the outer radial end of the housing connection portion 44 extends beyond the outer edge of the tab connection portion 43. An air vent portion 41 and a guiding portion 42 are both provided on the tab connection portion 43. The air vent portion 41 is provided in the central region of the first current collector 4. At least one guiding portion 42 includes a plurality of guiding portions 42 arranged uniformly in the circumferential direction. Each guiding portion 42 extends radially. For example, four guiding portions 42 are provided. Positioning holes 424 are provided at the second ends of the two opposite second guiding portions 422 respectively, and a preset spacing portion 423 is provided between the first ends of the two second guiding portions 422 and the side wall of the air vent portion 41; the first ends of the two opposite first guiding portions 421 are both communicated with the air vent portion 41, and positioning holes 424 are not provided at the second ends. The length of the second guiding portion 422 can be less than the length of the first guiding portion 421.

[0189] Although the present application has been described with reference to the preferred embodiments, various improvements can be made thereto and components therein can be replaced with equivalents without departing from the scope of the present application. In particular, as long as there is no structural conflict, the technical features mentioned in each embodiment can be combined in any way. The present application is not limited to the specific embodiments disclosed in the text, but includes all technical solutions falling within the scope of the claims.

Claims

1. A battery cell, characterized in that: include: The housing (1) comprises a first wall (12), wherein the first wall (12) is provided with a pressure relief component (2); An electrode terminal (6) is insulated and arranged on the housing (1); An electrode assembly (3) is arranged in the housing (1), the electrode assembly (3) comprising an electrode body (31) and a first electrode tab (32), the first electrode tab (32) being led out from one end of the electrode body (31); and The first current collecting member (4) is configured to electrically connect the first pole lug (32) and the housing (1), and the first current collecting member (4) is at least partially located between the first pole lug (32) and the pressure relief component (2). The first current collecting member (4) is provided with at least one vent (41) and at least one guide portion (42), the vent (41) penetrates the first current collecting member (4) along the thickness direction of the first wall (12), and the guide portion (42) is provided in the peripheral area of ​​the vent (41).

2. The battery cell according to claim 1, characterized in that: The guide portion (42) includes at least one of a through hole (42A) or a notch (42B).

3. The battery cell according to claim 1, characterized in that: The guide portion (42) extends in a radial direction of the first current collecting member (4).

4. The battery cell according to claim 1, characterized in that: The at least one guide portion (42) comprises a first guide portion (421), and the first guide portion (421) is connected to the vent portion (41) near a first end of the vent portion (41).

5. The battery cell according to claim 4, characterized in that: The two first guide portions (421) are located on the same straight line, and the first ends of the two first guide portions (421) close to the ventilating portion (41) are both in communication with the ventilating portion (41).

6. The battery cell according to claim 1, characterized in that: The at least one guide portion (42) comprises a second guide portion (422), and a preset spacing portion (423) is provided between the first end of the second guide portion (422) close to the vent portion (41) and the side wall of the vent portion (41).

7. The battery cell according to claim 6, characterized in that: The two second guide portions (422) are located on the same straight line, and a preset spacing portion (423) is provided between the first ends of the two second guide portions (422) and the side wall of the ventilating portion (41).

8. The battery cell according to claim 6, characterized in that: The preset spacer (423) is configured to be destroyed when the air pressure in the housing (1) exceeds a preset threshold.

9. The battery cell according to claim 6, characterized in that: The length (X) of the preset spacer (423) is less than 15 mm, and the thickness of the preset spacer (423) is less than 2 mm.

10. The battery cell according to claim 1, characterized in that: A plurality of guide portions (42) are arranged at intervals along the circumferential direction of the first current collecting member (4).

11. The battery cell according to claim 10, characterized in that: The plurality of guide portions (42) are arranged in a centrally symmetrical manner relative to the center of the first current collecting member (4).

12. The battery cell according to claim 11, characterized in that: The distance between the second ends of the two guide portions (42) located on the same straight line and away from the ventilation portion (41) is L, and the maximum radial dimension of the first current collecting member (4) is D, where L=0.1D-0.8D.

13. The battery cell according to claim 12, characterized in that: The thickness of the region of the first current collecting member (4) where the guide portion (42) is located is T, and the width of the guide portion (42) is W, where W=T-5T.

14. The battery cell according to claim 1, characterized in that: The first current collecting member (4) is provided with a positioning hole (424) at a second end away from the ventilating portion (41).

15. The battery cell according to claim 14, characterized in that: The at least one guide portion (42) comprises a plurality of guide portions (42) extending radially along the first current collecting member (4), two of the plurality of guide portions (42) being located on the same straight line, two positioning holes (424) being provided, and the two positioning holes (424) being respectively provided at the second ends of the two guide portions (42) being located on the same straight line.

16. The battery cell according to claim 15, characterized in that: The positioning hole (424) is a circular hole, the thickness of the region of the first current collecting member (4) where the guide portion (42) is located is T, the diameter of the circular hole is d, and d=4T-10T.

17. The battery cell according to any one of claims 1 to 16, characterized in that: The vent portion (41) is polygonal, and the guide portion (42) is close to the first end of the vent portion (41) and is aligned with the corner area of ​​the vent portion (41).

18. The battery cell according to claim 17, characterized in that: A plurality of the guide parts (42) are provided, and the number of the guide parts (42) is consistent with the number of the folded corners of the polygon. The plurality of guide parts (42) are arranged in one-to-one correspondence with the plurality of folded corners of the polygon.

19. The battery cell according to any one of claims 1 to 16, characterized in that: The first current collector (4) comprises a shell connecting portion (44) and a pole lug connecting portion (43) having different base materials, the shell connecting portion (44) having the same base material as the first wall (12), the pole lug connecting portion (43) having the same base material as the first pole lug (32), and the venting portion (41) and the guiding portion (42) being arranged on the pole lug connecting portion (43).

20. The battery cell according to claim 19, characterized in that: The pole lug connecting portion (43) and the first pole lug (32) are welded to form a weld mark, and the weld mark and the guide portion (42) are arranged at intervals in the circumferential direction.

21. The battery cell according to any one of claims 1 to 16, characterized in that: The vent (41) is arranged in a central area of ​​the first current collecting member (4).

22. The battery cell according to any one of claims 1 to 16, characterized in that: The housing (1) comprises a shell (10) and an end cover (12'), the shell (10) having an opening, the end cover (12') closing the opening, and the first wall (12) being the end cover (12') or a bottom wall (13) of the shell (10).

23. The battery cell according to claim 22, characterized in that: The first wall (12) is an end cover (12'); the bottom wall (13) is provided with the electrode terminal (6), and the electrode terminal (6) is insulated from the bottom wall (13); the electrode assembly (3) further comprises a second pole lug (33), the second pole lug (33) is led out from the other end of the electrode body (31), the second pole lug (33) has an opposite polarity to the first pole lug (32); the battery cell (100) further comprises a second current collector (5), the second current collector (5) is configured to electrically connect the second pole lug (33) and the electrode terminal (6).

24. A battery, characterized in that: A battery cell (100) comprising any one of claims 1 to 23.

25. An electrical device, characterized in that: It comprises the battery cell (100) according to any one of claims 1 to 23 and / or the battery (200) according to claim 24, and is used to provide electrical energy to the electrical device.

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