Battery monomer, battery and electric device

Abstract

The embodiment of the invention 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); 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

Battery cell, battery and electric device TECHNICAL FIELD

[0001] The present application relates to the technical field of batteries, in particular to a battery cell, a battery and an electric device. BACKGROUND

[0002] In recent years, new energy vehicles have made a great leap in development. In the field of electric vehicles, power batteries, as the power source of electric vehicles, play an irreplaceable role. With the vigorous promotion of new energy vehicles, the demand for power battery products is also increasing. As a core component of new energy vehicles, batteries have high requirements in terms of use safety.

[0003] However, how to improve the safety of the battery during use has always been a problem in the industry.

[0004] SUMMARY

[0005] The purpose of the present application is to improve the working safety of the battery.

[0006] According to a first aspect of the present application, a battery cell is provided, comprising:

[0007] a housing comprising a first wall, the first wall being provided with a pressure relief component;

[0008] an electrode assembly arranged in the housing, the electrode assembly comprising an electrode body and a first tab, the first tab being led out from one end of the electrode body; and

[0009] a first current collector configured to electrically connect the first tab and the housing, the first current collector being at least partially located between the first tab and the pressure relief component, the first current collector being provided with at least one vent and at least one guide, the vent penetrating through the first current collector along the thickness direction of the first wall, and the guide being arranged at the outer peripheral region of the vent.

[0010] The embodiment provides the vent and the guide on the first current collector close to the pressure relief component. When the pressure is relieved, the guide weakens the structural strength of the first current collector. When the air pressure is large, the first current collector can be guided to crack along a preset path to deform or break, the exhaust area is increased, the vent and the guide can exhaust at the same time, the venting area of the gas in the electrode assembly to the pressure relief component is increased, the blockage during pressure relief is prevented, the gas can flow more smoothly to the pressure relief component to be discharged outside the battery cell, the air pressure inside and outside the battery cell is balanced, and the heat is discharged in time, thereby improving the safety of the battery cell during use.

[0011] In some embodiments, the guide comprises at least one of a through hole or a notch.

[0012] The guiding part is arranged as a through hole, in the case of thermal runaway, the gas is more likely to directly enter the through hole from the venting part, so as to rapidly diffuse to the surrounding area, which is beneficial to improve the exhaust speed, and the through hole can fully play a role when the gas pressure in the battery monomer is relatively small, so that the gas can more smoothly reach the pressure relief component to be discharged, and the gas pressure inside and outside the battery monomer is balanced, thereby improving the safety of the battery monomer during use.

[0013] Or the guiding part is arranged as a notch, which can reduce the weakening of the strength of the first current collecting member, and is beneficial to ensure the strength of the first current collecting member, and in the case of thermal runaway, the notch forms a strength weakening area, the first current collecting member can be cracked along the notch, or further deformed at the notch, for example, the two sides of the notch are at different heights, which can effectively increase the exhaust area, so that the gas can more smoothly reach the pressure relief component to be discharged, and the gas pressure inside and outside the battery monomer is balanced, thereby improving the safety of the battery monomer during use.

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

[0015] This embodiment makes the guiding part extend along the radial direction of the first current collecting member, which is beneficial to guide the gas from the central area of the first current collecting member to the periphery, can quickly disperse the gas to prevent aggregation, can reduce the gas pressure near the venting part, and increase the exhaust speed, so that the gas can more smoothly reach the pressure relief component to be discharged to the outside of the battery monomer, and the gas pressure inside and outside the battery monomer is balanced, thereby improving the safety of the battery monomer during use.

[0016] Moreover, for the electrode assembly of the winding type, the first tab is a multi-layer structure, in order to ensure that each layer of the tab can be reliably welded, at least part of the welding mark is arranged along the radial direction, and such a guiding part is convenient for arranging the welding mark on the first current collecting member.

[0017] In some embodiments, the 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 in communication with the venting part.

[0018] This embodiment can make the gas directly act on the first end of the guiding part after reaching the venting part from the central hole of the electrode assembly, which is beneficial to make the first current collecting member deform or crack under the guidance of the guiding part, and the gas directly enters the guiding part along the communication position of the guiding part and the venting part, which can basically realize the simultaneous exhaust of the venting part and the guiding part in communication therewith, and can improve the exhaust speed.

[0019] In some embodiments, the two first guiding parts are located on the same straight line, and the first end of each of the two first guiding parts close to the venting part is in communication with the venting part.

[0020] The embodiment makes the two first guide parts located on the same straight line, and after the gas reaches the venting part from the center hole of the electrode assembly, the deformation or cracking of the area on the first current collector for exhaust is symmetrical, so that the gas distribution of the first current collector is balanced in the circumferential direction, the gas is prevented from gathering on the same side to cause pressure rise, the gas can more smoothly reach the pressure relief component for exhaust, and the internal and external air pressures of the battery monomer are balanced.

[0021] In some embodiments, the at least one guide part includes a second guide part, and the second guide part is provided with a preset interval part between the first end of the venting part and the side wall of the venting part.

[0022] The embodiment is based on the increase of the exhaust area by the arrangement of the guide part, and the preset interval part between the second guide part and the venting part is beneficial to improve the structural strength of the first current collector.

[0023] In some embodiments, the two second guide parts are located on the same straight line, and the preset interval part is arranged between the first end of the two second guide parts and the side wall of the venting part.

[0024] The embodiment makes the two second guide parts located on the same straight line, and the preset interval part is arranged at the opposite positions of the venting part, which can improve the structural symmetry of the first current collector, make the strength distribution more balanced, is beneficial to ensure the structural strength of the first current collector under the normal working condition of the battery monomer, and improve the reliability of the electrical connection between the first current collector and the first tab.

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

[0026] The second guide part of the embodiment is beneficial to ensure the structural strength of the first current collector under the normal working condition of the battery monomer, and can also damage the preset interval part when the battery monomer is in thermal runaway, so that the gas is more easily from the venting part to the second guide part, thereby increasing the exhaust area and facilitating the smooth exhaust of the internal gas.

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

[0028] The embodiment limits the length and thickness of the preset interval part, which can ensure that it reliably cracks when the battery monomer is in thermal runaway, and after the gas reaches the venting part from the center hole of the electrode assembly, it can smoothly enter the second guide part, thereby increasing the venting area, so that the gas can be more quickly exhausted by the pressure relief component, the internal and external air pressures of the battery monomer are balanced, and the safety of the battery monomer in thermal runaway is improved.

[0029] In some embodiments, the plurality of guide parts are arranged at intervals along the circumferential direction of the first current collector.

[0030] The embodiment is provided with a plurality of guide portions at a circumferential interval of the first current collector, which can improve the uniformity of gas discharge at the entire circumference of the first current collector, fully utilize the exhaust gas at different circumferential positions, increase the exhaust gas speed, and make the gas more smoothly reach the pressure relief component to be discharged out of the battery monomer.

[0031] In some embodiments, the plurality of guide portions are centrally symmetrically arranged relative to the center of the first current collector.

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

[0033] In some embodiments, the distance between the two guide portions located on the same straight line and away from the second end of the venting portion is L, the maximum radial dimension of the first current collector is D, and L = 0.1D-0.8D.

[0034] The embodiment designs the length of the guide portion according to the diameter of the first current collector, so that the guide portion can meet the requirement of the exhaust gas speed and 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 guide portion is arranged is T, and the width of the guide portion is W, and W = T-5T.

[0036] The embodiment designs the width of the guide portion according to the thickness of the region of the first current collector where the guide portion is arranged, so that the width of the guide portion is not less than the thickness, which can ensure that the guide portion is easy to crack when pressure relief and effectively increase the venting area, and the width of the guide portion is not more 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 venting portion.

[0038] The embodiment can further increase the exhaust gas area by arranging the positioning hole, and the positioning hole can play a positioning role in the stacking process after the first current collector is processed, so as to prevent deflection. In the process of assembling the battery monomer, when the automatic pickup device obtains the first current collector and places it on the end of the first tab, for example, the first current collector is sucked by a negative pressure suction nozzle, the guide portion of each first current collector can be at the same circumferential position, so that each battery monomer can be welded with the first current collector and the first tab according to the pre-set welding track, without the need to re-adjust the welding track, which can improve the assembly efficiency of the battery monomer.

[0039] Moreover, the positioning hole is smaller in size than the outer periphery of the first current collector, so the machining precision is easy to guarantee, and the positioning precision is improved. In addition, the positioning hole is arranged at the second end of the guide portion, which is far from the center, so the positioning effect is improved.

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

[0041] In this embodiment, the positioning hole is arranged only at the second end of each of the two guide portions on the same straight line, so that the plurality of guide portions have differences, thereby better playing a positioning role, preventing deflection, and reducing the weakening effect of the positioning hole on the strength of the first current collector.

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

[0043] In this embodiment, the diameter of the positioning hole is designed according to the thickness of the region where the guide portion is arranged on the first current collector, so that the diameter of the positioning hole is not less than 4 times the thickness of the first current collector, the size of the positioning hole is convenient for positioning, and the diameter of the positioning hole is not more than 10 times the thickness of the first current collector, so as to guarantee the structural strength of the first current collector.

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

[0045] In this embodiment, when the battery monomer is in thermal runaway and releases internal gas, the force acting on the first current collector can cause stress concentration at the corner region of the ventilation portion, so as to tear the first current collector from the corner of the ventilation portion. The first end of the guide portion close to the ventilation portion is aligned with the corner region of the ventilation portion, so that the force generated by the tearing of the corner region is further transmitted to the first end of the guide portion, so that the first current collector is deformed or torn in the guide portion region. The area of the first current collector can be increased when the thermal runaway occurs, the gas can be reduced, the exhaust smoothness and exhaust efficiency can be improved, the risk of fire and explosion caused by uneven pressure relief of the battery monomer can be reduced, and the safety of the battery monomer can be improved.

[0046] In some embodiments, a plurality of guide portions are arranged, and the number of guide portions is consistent with the number of corners of the polygon, and the plurality of guide portions are arranged one by one corresponding to the plurality of corners of the polygon.

[0047] The embodiment is provided with a guide part at the position corresponding to each of the folding angles of the ventilation part, and the stress concentration at each of the folding angles can be fully utilized to promote the first current collector to deform or crack further along the guide part, so as to increase the ventilation area of the first current collector in the thermal runaway as much as possible, and make the exhaust more smooth.

[0048] In some embodiments, the first current collector includes a shell connecting part and a tab connecting part with different base materials, the shell connecting part has the same base material as the first wall, the tab connecting part has the same base material as the first tab, and the ventilation part and the guide part are arranged on the tab connecting part.

[0049] In the embodiment, after the first wall and the first current collector are welded, the difference between the thermal expansion coefficients of the materials of the shell connecting part and the first wall does not exceed a preset threshold, and the two materials shrink to different degrees when cooled, which is easy to cause welding cracks, so that the liquid leakage problem can be prevented, and the reliability of the battery monomer in operation is improved.

[0050] In some embodiments, the tab connecting part is welded with the first tab to form a welding mark, and the welding mark and the guide part are arranged at intervals in the circumferential direction.

[0051] In the embodiment, the welding mark and the guide part are arranged at intervals in the circumferential direction, so that the heat generated in the welding process can be prevented from damaging the guide part, so as to ensure the structural strength of the first current collector in normal use.

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

[0053] In the embodiment, the ventilation part is arranged in the central region of the first current collector, so that part of the gas discharged along the central hole of the electrode assembly can directly pass through the ventilation part to reach the pressure relief part, the pressure relief resistance of the battery monomer in the thermal runaway is reduced, and the exhaust efficiency is improved. Moreover, the ventilation part arranged in the central region is conducive to promoting the guide part located in the peripheral region to crack to deform or damage when discharging the gas, so that the ventilation part and the guide part jointly achieve a better pressure relief effect. In some embodiments, the shell includes a shell body and an end cover, the shell body has an opening, the end cover closes the opening, and the first wall is a bottom wall of the end cover or the shell body.

[0054] In the embodiment, the shell is formed by connecting the shell body and the end cover, so that the installation of the internal structure can be conveniently performed.

[0055] In some embodiments, the first wall is the end cover, the bottom wall is provided with an electrode terminal, 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 main body, the second tab has an opposite polarity to the first tab, and the battery monomer further includes a second current collector configured to electrically connect the second tab and the electrode terminal.

[0056] The battery cell of the embodiment has the electrode terminal arranged at the end far from the pressure relief component. When thermal runaway occurs, the discharge will be ejected from the end where the pressure relief component is arranged, far from the electrode terminal, thereby far from the busbar for electrically connecting the plurality of battery cells, so as to reduce the influence on the electrical connection of the battery cell when thermal runaway occurs.

[0057] According to a second aspect of the present application, a battery is provided, comprising the battery cell of the above-mentioned embodiments.

[0058] According to a third aspect of the present application, a use electric device is provided, comprising the battery cell and / or the battery of the above-mentioned embodiments, for providing electric energy for the use electric device. BRIEF DESCRIPTION OF DRAWINGS

[0059] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed to be used in the embodiments of the present application will be briefly introduced as follows. Obviously, the drawings described below are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor on the basis of the drawings.

[0060] FIG. 1 is a structural schematic diagram of some embodiments of the present application in which the battery is installed in a vehicle.

[0061] FIG. 2 is an exploded view of a first embodiment of the battery of the present application.

[0062] FIG. 3 is an exploded view of some embodiments of the battery cell of the present application.

[0063] FIG. 4 is a front view of some embodiments of the first busbar in the battery cell of the present application.

[0064] FIG. 5 is an A-A sectional view of FIG. 4.

[0065] FIG. 6 is a structural schematic diagram of a variant of FIG. 4.

[0066] FIG. 7 is a structural schematic diagram of another variant of FIG. 4.

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

[0068] Label description: 100, battery monomer; 1, shell; 10, shell; 11, side wall; 12, first wall; 12', end cover; 13, bottom wall; 2, pressure relief component; 3, electrode assembly; 31, electrode body; 32, first tab; 33, second tab; 34, center hole; 4, first current collector; 41, air passage; 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 connecting part; 44, shell connecting part; 5, second current collector; 6, electrode terminal; 200, battery; 201, box assembly; 201A, box; 201B, first cover; 201C, second cover; 300, vehicle; 301, axle; 302, wheel; 303, motor; 304, controller. DETAILED DESCRIPTION

[0069] The embodiments of the present application will be further described in details below with reference to the drawings and examples. The detailed description and drawings of the following examples are used to exemplarily illustrate the principles of the present application, but cannot be used to limit the scope of the present application, i.e., the present application is not limited to the described examples.

[0070] In the description of the embodiments of the present application, the term "a plurality of" refers to two or more (including two), and similarly, "a plurality of groups" refers to two or more groups (including two groups), and "a plurality of pieces" refers to two or more pieces (including two pieces).

[0071] The present application uses the description of the orientation or position relationship indicated by "upper", "lower", "top", "bottom", "front", "rear", "inner" and "outer" and the like. This is only for the convenience of describing the present application, and is not intended to indicate or imply that the device referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the scope of protection of the present application.

[0072] In addition, the terms "first", "second", "third" and the like are only for descriptive purposes and cannot be understood as indicating or implying relative importance. "Vertical" is not strictly vertical, but within the allowable range of error. "Parallel" is not strictly parallel, but within the allowable range of error. The orientation words appearing in the following description are the directions shown in the drawings, and are not limited to the specific structure of the present application.

[0073] In the description of the present application, it should be further pointed out that, unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connection" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be directly connected, or indirectly connected through an intermediate medium. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0074] Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least some embodiments of the application. The appearances of the phrase "in one embodiment" in various places in the specification are not necessarily all referring to the same embodiment, nor are they necessarily all

[0075] A conventional battery cell generally includes a case and an electrode assembly received in the case, and is filled with an electrolyte in the case. The electrode assembly is mainly formed by stacking or winding a first electrode sheet and a second electrode sheet having opposite polarities, and an insulating member such as a separator is generally provided between the first electrode sheet and the second electrode sheet. The portions of the first electrode sheet and the second electrode sheet to which active materials are applied constitute a main body of the electrode assembly, and the portions of the first electrode sheet and the second electrode sheet to which the active materials are not applied each constitute a first tab and a second tab. In the battery cell, the first electrode sheet can be a positive electrode sheet including a positive electrode current collector and positive electrode active material layers provided on both sides of the positive electrode current collector, and the positive electrode current collector can be a metal foil or a composite current collector. For example, as the metal foil, silver-surface-treated aluminum or stainless steel, stainless steel, copper, aluminum, nickel, a carbon electrode, carbon, nickel, or titanium, or the like can be used. The composite current collector can include a polymer material base layer and a metal layer. The composite current collector can be formed by forming a metal material (aluminum, an aluminum alloy, nickel, a nickel alloy, titanium, a titanium alloy, silver, and a silver alloy, or the like) on a polymer material base material (such as a base material of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, or the like). The positive electrode active material layer can include at least one of lithium-containing phosphates, lithium transition metal oxides, and modified compounds of each thereof. However, the present application is not limited to these materials, and other conventional materials that can be used as a positive electrode active material for a battery can also be used. These positive electrode active materials can be used alone or in combination of two or more. The second electrode sheet can be a negative electrode sheet including a negative electrode current collector and negative electrode active material layers provided on both sides of the negative electrode current collector, and the negative electrode current collector can be a metal foil or a composite current collector. For example, as the metal foil, silver-surface-treated aluminum or stainless steel, stainless steel, copper, aluminum, nickel, a carbon electrode, carbon, nickel, or titanium, or the like can be used. The composite current collector can include a polymer material base layer and a metal layer. The composite current collector can be formed by forming a metal material (copper, a copper alloy, nickel, a nickel alloy, titanium, a titanium alloy, silver, and a silver alloy, or the like) on a polymer material base material (such as a base material of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, or the like). The negative electrode active material layer can use a negative electrode active material for a battery known in the art. As an example, the negative electrode active material can include at least one of artificial graphite, natural graphite, soft carbon, hard carbon, a silicon-based material, a tin-based material, lithium titanate, or the like. Alternatively, the first electrode sheet can also be a negative electrode sheet, and the second electrode sheet can be a positive electrode sheet accordingly. The first tab and the second tab can be located at one end of the main body or at both ends of the main body, respectively. During charging and discharging of the battery cell, the positive electrode active material and the negative electrode active material react with the electrolyte, and the tabs connect electrode terminals to form a current loop.

[0076] At present, the cylindrical battery cell still has poor safety in use. It is found through research that the main reason for the poor safety of the battery cell is that, after thermal runaway occurs, the high-temperature flue gas and active substances generated in the electrode assembly flow towards the pressure relief component through the through hole in the center of the current collector, and are discharged through the pressure relief component at the end of the shell. However, since the through hole in the center of the current collector is small, when the internal pressure of the battery cell is too large, the exhaust will not be smooth, the high pressure in the battery cell cannot be relieved in time, and thus the safety of the battery cell in operation is affected.

[0077] Based on the shortcomings of the above solutions, the battery cell provided in the present application includes: a shell including a first wall, the first wall being provided with a pressure relief component; an electrode assembly arranged in the shell, the electrode assembly including an electrode body and a first tab, the first tab being led out from one end of the electrode body; and a first current collector configured to electrically connect the first tab and the shell, and the first current collector being at least partially located between the first tab and the pressure relief component, the first current collector being provided with at least one ventilation part and at least one guide part, the ventilation part penetrating through the first current collector along the thickness direction of the first wall, and the guide part being arranged at the outer peripheral region of the ventilation part.

[0078] The battery cell of the embodiment is provided with the ventilation part and the guide part on the first current collector close to the pressure relief component. When the pressure is relieved, the guide part weakens the structural strength of the first current collector, and when the pressure is large, the first current collector can be guided to crack and deform or break along a preset path, the exhaust area is increased, the exhaust can be performed simultaneously through the ventilation part and the guide part, the ventilation area of the gas in the electrode assembly to the pressure relief component is increased, the blockage during pressure relief is prevented, the gas can flow more smoothly to the pressure relief component to be discharged outside the battery cell, the internal and external pressures of the battery cell are balanced, and the heat is discharged in time, thereby improving the safety of the battery cell in use.

[0079] The battery cell of the embodiment of the present application is suitable for a battery and an electric device using such a battery cell, and the battery is also suitable for an electric device.

[0080] The battery of the embodiment of the present application can be used in an electric device. The electric device can be a battery car, an electric vehicle, a ship or a spacecraft, etc., for example, the spacecraft includes an airplane, a rocket, a space shuttle and a spaceship, etc.

[0081] As shown in FIG. 1, the power consuming device can be a vehicle 300, for example, a new energy vehicle, which can be a pure electric vehicle, a hybrid vehicle or a range extended vehicle, etc.; or the power consuming device can also be a drone or a ship, etc. Specifically, the vehicle 300 can include an axle 301, a wheel 302 connected to the axle 301, a motor 303 for driving the axle 301 to rotate, a controller 304 for controlling the motor 303 to work, and a battery 200 which can be arranged at the bottom, head or tail of the vehicle 300 and is used to provide electric energy for the motor 303 and other components in the vehicle to work.

[0082] As shown in FIG. 2, the battery 200 includes a box assembly 201 and a battery cell 100. In the battery 200, the battery cell 100 can be one or multiple. If the battery cell 100 is multiple, the multiple battery cells 100 can be connected in series, in parallel or in a mixed manner. The mixed manner means that the multiple battery cells 100 are connected in series and in parallel. The multiple battery cells 100 can be connected in series, in parallel or in a mixed manner to form a battery module, and the multiple battery modules are connected in series, in parallel or in a mixed manner to form a whole which is accommodated in the box assembly 201. Alternatively, all the battery cells 100 can be directly connected in series, in parallel or in a mixed manner, and the whole formed by the battery cells 100 is accommodated in the box assembly 201.

[0083] The box assembly 201 can be a part of a battery pack and is detachably mounted on the power consuming device. Alternatively, the box assembly 201 can be a space formed by a structural member in the power consuming device for accommodating the battery cell 100. For example, when the battery cell 100 is used in the vehicle 300, the box assembly 201 is a space formed by a vehicle frame for accommodating the battery cell 100.

[0084] The box assembly 201 is hollow inside and is used to accommodate one or multiple battery cells 100. According to the shape, number, combination manner and other requirements of the battery cells 100 to be accommodated, the box assembly 201 can have different sizes and shapes. For example, the box assembly 201 can include a box 201A, a first cover 201B and a second cover 201C. The box 201A has openings at both ends, and the first cover 201B and the second cover 201C are used to close the openings at both ends of the box 201A. In FIG. 2, according to the arrangement manner of the multiple battery cells 100, the box 201A has a rectangular cylindrical structure. In order to facilitate the maintenance of the battery 200, the box assembly 201 is detachably mounted on the power consuming device.

[0085] The battery cell 100 can be a secondary battery, which means that the battery cell 100 can be activated by charging after discharging and can continue to be used.

[0086] 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-hydrogen battery, a nickel-cadmium battery, a lead-acid battery, etc., and the present application is not limited thereto.

[0087] As an example, the battery cell 100 can be a cylindrical battery cell, a prismatic battery cell, a soft-pack battery cell, or a battery cell of other shapes, and the prismatic battery cell includes a square battery cell, a blade battery cell, a multi-prismatic battery cell, such as a hexagonal battery cell, etc., and the present application is not particularly limited.

[0088] The subsequent description is described by taking the cylindrical battery cell 100 as an example, 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 the 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.

[0089] FIG. 3 is an exploded view of some embodiments of the battery cell of the present application, and FIG. 4 is a structural schematic view of some embodiments of the first current collector. In some embodiments, the battery cell 100 includes: a shell 1 including a first wall 12, the first wall 12 being provided with a pressure relief component 2; an electrode assembly 3 arranged in the shell 1, the electrode assembly 3 including an electrode body 31 and a first tab 32, the first tab 32 being led out from one end of the electrode body 31; and a first current collector 4 configured to electrically connect the first tab 32 and the shell 1, and the first current collector 4 is at least partially located between the first tab 32 and the pressure relief component 2, and the first current collector 4 is provided with at least one vent 41 and at least one guide 42, the vent 41 penetrating the first current collector 4 along the thickness direction of the first wall 12, and the guide 42 is arranged at the outer peripheral region of the vent 41.

[0090] The shell 1 adopts a thin-walled hollow structure for accommodating the electrode assembly 3 and the electrolyte, and the shell 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 shell 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 being oppositely arranged, and the side wall 11 being connected between the first wall 12 and the second wall.

[0091] The pressure relief component 2 is arranged on the first wall 12, and the pressure relief component 2 can be integrally formed with the first wall 12, such as being arranged on the inner surface or the outer surface of the first wall 12 to form the pressure relief component 2; or the pressure relief component 2 and the first wall 12 adopt a split structure, the pressure relief component 2 is separately processed in advance, and then is fixed to the first wall 12 by welding or other means.

[0092] The pressure relief component 2 refers to an element or component that is actuated to release the internal pressure or temperature of the battery cell 100 when the internal pressure or temperature reaches a predetermined threshold. The threshold is designed differently according to the design requirements. The threshold can depend on the material of one or several of the positive electrode tab, the negative electrode tab, the electrolyte, and the separator in the battery cell. The pressure relief component 2 can take the form of, for example, a pressure relief valve, a gas valve, a pressure relief valve, or a safety valve, and can specifically take the form of a pressure-sensitive or temperature-sensitive element or structure, i.e., 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 broken, thereby forming an opening or passage for the internal pressure or temperature of the battery cell 100 to be released.

[0093] The "actuation" referred to herein means that the pressure relief component 2 generates an action or is activated to a certain state, so that the internal pressure and temperature of the battery cell 100 can be released. The action generated by the pressure relief component 2 can include, but is not limited to, at least one of the following: the pressure relief component 2 is broken, cracked, torn, or opened, etc. When the pressure relief component 2 is actuated, the internal discharge of the battery cell 100 is discharged outward from the actuated part. In this way, the battery cell 100 can be relieved of pressure and temperature in a controllable manner, thereby avoiding potential more serious accidents. The discharge from the battery cell 100 referred to herein includes, but is 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 CH4, CO, and other flammable gases), flames, etc.

[0094] The electrode assembly 3 is formed by winding the first and second electrode tabs of opposite polarity around a winding axis K, which is aligned with the first direction z, and a separator, such as a separator film, is usually provided between the first and second electrode tabs. For a cylindrical battery cell 100, the electrode assembly 3 after winding can be in a cylindrical shape; for a cuboid battery cell 100, the electrode assembly 3 after winding can be in a flat shape.

[0095] The part of the first and second electrode tabs coated with active material constitutes an electrode body 31, which is provided with a central hole 34 extending along the winding axis K for accommodating electrolyte or serving as an exhaust passage when pressure relief. The part of the first and second electrode tabs not coated with active material each constitutes a first and second tab 32 and 33, one of which is a negative electrode tab and the other of which is a positive electrode tab. The first and second tabs 32 and 33 are respectively led out from both ends of the electrode body 31.

[0096] The first current collector 4 is configured to electrically connect the first tab 32 and the first wall 12, and is located between the first tab 32 and the first wall 12. The electrical connection mentioned herein can be achieved by welding, for example, laser welding. The first current collector 4 can have a thin plate structure, for example, a thin plate with uniform thickness, or a structure with concave-convex or bending in a local part of the thin plate. For a cylindrical battery cell 100, the first current collector 4 can be disc-shaped.

[0097] The first current collector 4 is provided with a venting portion 41 and a guiding portion 42. The venting portion 41 penetrates in the thickness direction of the first current collector 4, and is used to form a channel for discharging gas in the electrode assembly 3 to the pressure relief component 2. The venting portion 41 can have a circular, elliptical, polygonal, or other shape. There can be one or more venting portions 41.

[0098] The guiding portion 42 is provided in the outer peripheral region of the venting portion 41. The guiding portion 42 can be spaced apart from the venting portion 41, or can be in communication with the venting portion 41. The shape of the guiding portion 42 can be designed to facilitate the gas reaching the pressure relief component 2. The guiding portion 42 is used to weaken the strength of the first current collector 4 to guide the first current collector 4 to crack and increase the gas discharge area during the pressure relief process, and to discharge gas together with the venting portion 41. When multiple guiding portions 42 are provided, they can be uniformly distributed on the first current collector 4 to make the strength uniform and facilitate the guiding of gas from the central region to the periphery. For example, the guiding portion 42 can have a circular, elliptical, polygonal, or other shape, or an elongated shape extending in a straight line or a curve.

[0099] This embodiment provides the first current collector 4 with the venting portion 41 and the guiding portion 42 near the pressure relief component 2. During pressure relief, the guiding portion 42 weakens the structural strength of the first current collector 4, and when the gas pressure is large, it can guide the first current collector 4 to crack according to a preset path to deform or break, increase the gas discharge area, and discharge gas through the venting portion 41 and the guiding portion 42 at the same time, thereby increasing the venting area of the gas in the electrode assembly 3 to the pressure relief component 2, preventing blockage during pressure relief, and making the gas flow more smoothly to the pressure relief component 2 to discharge the battery cell 100, balancing the gas pressure inside and outside the battery cell 100, and timely discharging heat, thereby improving the safety of the battery cell 100 during use.

[0100] In some embodiments, the venting portion 41 is provided in the central region of the first current collector 4.

[0101] The central region of the first current collector 4 is provided with one or more venting portions 41, which can be aligned with the central hole 34 of the electrode assembly 3, and the area of at least one of the venting portions 41 can be close to that of the central hole 34. The term "central region" as used herein is not limited to the exact center, for example, the venting portion 41 can be offset from the exact center due to machining errors, or there can be multiple venting portions 41 distributed within a certain range of the central region, but the exact center can not be provided with a venting portion 41, for example, the multiple venting portions 41 are arranged in a ring shape, or on this basis, a venting portion 41 is additionally provided at the exact center.

[0102] The embodiment provides the venting portion 41 at the central region 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 venting portion 41 to the pressure relief component 2, reducing the pressure relief resistance when the battery monomer 100 is in thermal runaway, and improving the exhaust efficiency. Moreover, the venting portion 41 provided at the central region is conducive to promoting the deformation or destruction of the guide portion 42 located at the peripheral region when the gas is discharged, so that the venting portion 41 and the guide portion 42 together achieve a more optimal pressure relief effect.

[0103] In some embodiments, as shown in FIG. 5, the guide portion 42 includes at least one of a through hole 42A or a notch 42B.

[0104] As shown in FIG. 5, the guide portion 42 includes the through hole 42A, which penetrates through the thickness direction of the first current collector 4, and the through hole 42A extends in an elongated shape with a straight or curved trajectory. The straight extension can reduce the resistance when the gas flows, and is conducive to processing, or can also be circular, elliptical, polygonal or other special-shaped structures.

[0105] Providing the guide portion 42 in an elongated shape has the following advantages: on the basis of guiding the first current collector 4 to crack and increase the exhaust area, since the width dimension of the guide portion 42 perpendicular to the extension direction is small, the structural strength of the first current collector 4 can be more easily ensured under normal use conditions, and deformation is less likely to occur, which can improve the reliability of the electrical connection between the first tab 32 and the first current collector 4. Moreover, when the first tab 32 and the first current collector 4 are electrically connected by welding, the influence on the welding area can be reduced, and if the welding trajectory avoids the guide portion 42, the area and uniformity of the welding trajectory distributed on the end surface of the first tab 32 can also be ensured, which can improve the reliability of the electrical connection between the first tab 32 and the first current collector 4.

[0106] As shown in FIG. 6, the guide portion 42 includes a notch 42B, which can be provided on the side of the first current collector 4 close to the first wall 12 or on the side of the first current collector 4 close to the first tab 32. The notch 42B is provided in a partial thickness of the first current collector 4 and does not penetrate the entire thickness. By providing the notch 42B, a thickness-reduced portion is formed. The notch 42B can be in an elongated shape extending in a straight or curved trajectory.

[0107] As shown in FIG. 7, the guide portion 42 of FIGS. 5 and 6 extends in a continuous trajectory. The difference of FIG. 7 is that the guide portion 42 extends in an intermittent trajectory to form a broken line. The guide portion 42 is formed by the through hole 42A or the notch 42B or a combination of the through hole 42A and the notch 42B.

[0108] In the same first current collector 4, only one kind of guide portion 42 can be provided, or two or more kinds of guide portions 42 can be provided in combination.

[0109] In this embodiment, the guide portion 42 is provided as the through hole 42A. In the case of thermal runaway, the gas is more likely to directly enter the through hole 42A from the vent portion 41 so as to rapidly diffuse to the surrounding area, which is conducive to improving the exhaust speed. The through hole 42A can fully play a role when the gas pressure inside the battery monomer 100 is relatively small, so that the gas can more smoothly reach the pressure relief component 2 for discharge, the gas pressure inside and outside the battery monomer 100 is balanced, and thus the safety during use of the battery monomer 100 is improved.

[0110] Alternatively, the guide portion 42 is provided as the notch 42B, which can reduce the weakening of the strength of the first current collector 4 and is conducive to ensuring the strength of the first current collector 4. In the case of thermal runaway, a strength-weakened 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, so that the gas can more smoothly reach the pressure relief component 2 for discharge, the gas pressure inside and outside the battery monomer 100 is balanced, and thus the safety during use of the battery monomer 100 is improved.

[0111] In some embodiments, as shown in FIG. 4, the guide portion 42 extends along the radial direction of the first current collector 4.

[0112] When a plurality of guide portions 42 are provided, the plurality of guide portions 42 can form a radial pattern.

[0113] Alternatively, the guide portion 42 can also extend along the circumferential direction of the first current collector 4 or extend in other directions. For example, a plurality of guide portions 42 all extend along the circumferential direction and are distributed at different radial positions. The guide portions 42 at adjacent radial positions can be staggered, and one or more guide portions 42 can be provided at the same radial position.

[0114] The embodiment makes the guide portion 42 extend along the radial direction of the first current collector 4, which is conducive to guiding the gas from the central region of the first current collector 4 to the periphery, quickly dispersing the gas to prevent the gas from gathering, reducing the gas pressure near the venting portion 41, increasing the exhaust speed, and making the gas more smoothly reach the pressure relief component 2 to be discharged to the outside of the battery monomer 100, balancing the gas pressure inside and outside the battery monomer 100, thereby improving the safety of the battery monomer 100 during use.

[0115] Moreover, for the wound electrode assembly 3, the first tab 32 has a multi-layer structure, and in order to ensure that each layer of the tab can be reliably welded, at least part of the welding marks are arranged in the radial direction, and the guide portion 42 facilitates the arrangement of the welding marks on the first current collector 4.

[0116] In some embodiments, as shown in FIG. 4, the at least one guide portion 42 includes a first guide portion 421, and the first guide portion 421 is in communication with the venting portion 41 near the first end of the venting portion 41.

[0117] In some embodiments, the first end of the guide portion 42 is in communication with the venting portion 41, and the second end of the guide portion 42 has a preset interval from the outer edge of the first current collector 4.

[0118] The embodiment can make the gas, after reaching the venting portion 41 from the central hole 34 of the electrode assembly 3, directly act on the first end of the guide portion 42, which is conducive to deforming or cracking the first current collector 4 under the guidance of the guide portion 42, and the gas directly enters the guide portion 42 along the communication position between the guide portion 42 and the venting portion 41, which basically realizes the simultaneous exhaust of the venting portion 41 and the guide portion 42 in communication therewith, and improves the exhaust speed.

[0119] In some embodiments, the two first guide portions 421 are located on the same straight line, and the two first guide portions 421 are in communication with the venting portion 41 near the first end of the venting portion 41.

[0120] In some embodiments, the at least one guide portion 42 can include only two first guide portions 421 located on the same straight line, or the at least one guide portion 42 includes four or six or an even number of first guide portions 421, and each pair of first guide portions 421 is located on the same straight line.

[0121] The embodiment makes the two first guide portions 421 located on the same straight line, and after the gas reaches the venting portion 41 from the central hole 34 of the electrode assembly 3, the deformed or cracked region of the first current collector 4 for exhaust is symmetrical, thereby making the gas distribution of the first current collector 4 along the circumferential direction balanced, preventing the gas from gathering on the same side to cause the pressure to rise, making the gas more smoothly reach the pressure relief component 2 to be discharged, and balancing the gas pressure inside and outside the battery monomer 100.

[0122] In some embodiments, as shown in FIG. 4, the at least one guide portion 42 includes a second guide portion 422, and a preset interval portion 423 is arranged between the first end of the second guide portion 422 and the sidewall of the vent portion 41, i.e., the first end of the second guide portion 422 is not in communication with the vent portion 41.

[0123] This embodiment, on the basis of increasing the exhaust area by arranging the guide portion 42, improves the structural strength of the first current collector 4 by arranging the preset interval portion 423 between the second guide portion 422 and the vent portion 41.

[0124] In some embodiments, the two second guide portions 422 are located on the same straight line, and the preset interval portion 423 is arranged between the first end of each of the two second guide portions 422 and the sidewall of the vent portion 41.

[0125] In this case, the lengths X of the preset interval portions 423 corresponding to the two second guide portions 422 located on the same straight line can be the same, forming a symmetrical structure, or the lengths X of the two preset interval portions 423 are different.

[0126] As shown in FIG. 4, the plurality of guide portions 42 simultaneously include the first guide portion 421 and the second guide portion 422, and the first guide portion 421 and the second guide portion 422 can both extend in the radial direction. For example, two first guide portions 421 and two second guide portions 422 are uniformly and circumferentially arranged on the first current collector 4, the vent portion 41 is square, the first end of each of the two first guide portions 421 is in communication with the left and right top vertices of the vent portion 41, respectively, and the first end of each of the two second guide portions 422 is provided with a preset interval portion 423 between the upper and lower top vertices of the vent portion 41. In this way, the first guide portion 421 and the second guide portion 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.

[0127] In this structure, the first guide portion 421 of the plurality of guide portions 42 is in communication with the vent portion 41, which can make the gas directly enter the first guide portion 421 along the communication position between the guide portion 42 and the vent portion 41 after reaching the vent portion 41 from the center hole 34 of the electrode assembly 3, thereby improving the exhaust speed; the first end of the second guide portion 422 has the preset interval portion 423 with the sidewall of the vent portion 41, which is beneficial to ensuring the structural strength of the first current collector 4 under the normal working condition of the battery monomer 100 and improving the reliability of the electrical connection between the first current collector 4 and the first tab 32. In this way, this structure takes into account the exhaust speed and structural strength of the first current collector 4, and can simultaneously improve the safety and reliability of the battery monomer 100 in operation.

[0128] The embodiment makes two second guide portions 422 located on the same straight line, and the preset interval portions 423 are arranged at opposite positions of the venting portion 41, which can improve the structural symmetry of the first current collector 4, make the strength distribution more balanced, and be beneficial to guarantee the structural strength of the first current collector 4 in the normal working condition of the battery monomer 100, and improve the reliability of the electrical connection between the first current collector 4 and the first tab 32.

[0129] In some embodiments, the preset interval portion 423 is configured to be damaged when the air pressure in the shell 1 exceeds a preset threshold.

[0130] In the normal working condition of the battery monomer 100, the second guide portion 422 and the venting portion 41 are connected through the preset interval portion 423; in the case of thermal runaway, the connecting material between the second guide portion 422 and the venting portion 41 is damaged under the action of gas pressure and high temperature. The "damage" mentioned here can refer to the fracture, torsion or shedding of the preset interval portion 423.

[0131] The second guide portion 422 of the embodiment is beneficial to guarantee the structural strength of the first current collector 4 in the normal working condition of the battery monomer 100, and can also make the preset interval portion 423 damaged in the case of thermal runaway of the battery monomer 100, so that the gas is more easily from the venting portion 41 to the second guide portion 422, thereby increasing the exhaust area and being beneficial to the smooth discharge of the internal gas.

[0132] 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.

[0133] By limiting the length X and the thickness of the preset interval portion 423, it can be guaranteed that it can be reliably cracked in the case of thermal runaway of the battery monomer 100, and after the gas reaches the venting portion 41 from the center hole 34 of the electrode assembly 3, it can smoothly enter the second guide portion 422, thereby increasing the venting area, enabling the gas to be discharged more quickly by the pressure relief component 2, balancing the air pressure inside and outside the battery monomer 100, and improving the safety of the battery monomer 100 in the case of thermal runaway.

[0134] In some embodiments, the guide portion 42 is provided with a plurality of guide portions 42, and the plurality of guide portions 42 are arranged at intervals along the circumference of the first current collector 4.

[0135] The plurality of guide portions 42 are uniformly arranged at intervals along the circumference of the first current collector 4. The number of guide portions 42 is selected to not only guarantee the structural strength of the first current collector 4 in the normal use condition, and not to affect the reliable electrical connection between the first current collector 4 and the first tab 32, but also to guarantee sufficient venting area for the smooth discharge of the gas. For example, the guide portion 42 can be provided with two, three, four or more.

[0136] For example, the plurality of guide portions 42 each extend along a radial direction and are uniformly spaced along a circumferential direction of the first current collector 4, forming a radial pattern.

[0137] The plurality of guide portions 42 are spaced along a circumferential direction of the first current collector 4, which can improve the uniformity of gas discharge along the entire circumferential direction of the first current collector 4, fully utilize gas discharge at different positions along the circumferential direction, and increase the gas discharge speed, so that the gas can more smoothly reach the pressure relief component 2 to be discharged out of the battery monomer 100.

[0138] In some embodiments, the plurality of guide portions 42 are centrally symmetric with respect to the center of the first current collector 4.

[0139] This embodiment can make the distribution of the plurality of guide portions 42 on the first current collector 4 more uniform, which can not only make the structural strength of the first current collector 4 uniform, but also make the distribution of the gas discharge area uniform, while ensuring the reliability of the electrical connection between the first current collector 4 and the first tab 32 and the uniformity of gas discharge.

[0140] In some embodiments, the distance between the second ends of the two guide portions 42 located on the same straight line is L, the maximum radial dimension of the first current collector 4 is D, and L = 0.1D-0.8D.

[0141] This embodiment designs the length of the guide portion 42 according to the diameter D of the first current collector 4, so that the guide portion 42 can not only meet the requirement of gas discharge speed, but also ensure the structural strength of the first current collector 4.

[0142] In some embodiments, the thickness of the region of the first current collector 4 where the guide portion 42 is located is T, and the width of the guide portion 42 is W, W = T-5T.

[0143] As shown in FIG. 5, the first current collector 4 includes a shell connecting portion 44 and a tab connecting portion 43 stacked in the thickness direction, and the guide portion 42 is arranged on the tab connecting portion 43, i.e., the thickness of the tab connecting portion 43 is T.

[0144] This embodiment designs the width W of the guide portion 42 according to the thickness T of the region of the first current collector 4 where the guide portion 42 is located, so that the width W of the guide portion 42 is not less than the thickness T, which can ensure that the guide portion 42 is easy to crack when pressure relief and effectively increase the ventilation area, and the width W of the guide portion 42 is not more than 5 times the thickness T, which can ensure the structural strength of the first current collector 4.

[0145] In some embodiments, as shown in FIG. 4, the second end of the guide portion 42 away from the ventilation portion 41 is provided with a positioning hole 424.

[0146] For example, the positioning hole 424 can be a round hole, an oval hole, a polygonal hole, or the like. The positioning hole 424 is in communication with the second end of the guide portion 42. The positioning hole 424 plays a positioning role when the first current collector 4 is stacked, for example, a positioning column can be provided, and the positioning hole 424 passes through the positioning column each time the first current collector 4 is stacked.

[0147] This embodiment, by providing the positioning hole 424, not only further increases the exhaust area, but also plays a positioning role in the stacking process after the first current collector 4 is processed, preventing deflection. During the assembly of the battery monomer 100, when the automatic pickup device acquires the first current collector 4 and places it on the end of the first tab 32, for example, by a negative pressure suction nozzle to suck the first current collector 4, the guide portion 42 of each first current collector 4 can be at the same circumferential position, so that each battery monomer 100 can weld the first current collector 4 and the first tab 32 according to the pre-set welding track, without the need to adjust the welding track, which can improve the assembly efficiency of the battery monomer 100.

[0148] Moreover, positioning through the positioning hole 424, compared with positioning through the outer periphery of the first current collector 4, since the positioning hole 424 is small in size, it is easy to ensure the machining precision, and the positioning precision can be improved. In addition, the positioning hole 424 is arranged at the second end of the guide portion 42, which is far away from the center, and the positioning effect can be improved.

[0149] In some embodiments, the at least one guide portion 42 includes a plurality of guide portions 42 extending in the radial direction of the first current collector 4, two guide portions 42 of the plurality of guide portions 42 are located on the same straight line, and the positioning hole 424 is provided with two positioning holes 424, and the two positioning holes 424 are respectively arranged at the second ends of the two guide portions 42 on the same straight line.

[0150] As shown in FIG. 4, the second ends of the two opposite guide portions 42 are provided with the positioning hole 424, and the second ends of the remaining two guide portions 42 are not provided with the positioning hole 424.

[0151] This embodiment only provides the positioning hole 424 at the second end of each of the two guide portions 42 on the same straight line, so that there is a difference between the plurality of guide portions 42, which can better play a positioning role and prevent deflection, and can also reduce the weakening effect of the positioning hole 424 on the strength of the first current collector 4.

[0152] Optionally, if all the second ends of the guide portions 42 are provided with the positioning holes 424, or if all the second ends of the guide portions 42 are not provided with the positioning holes 424. For this structure, since there is no positioning structure on the first current collector 4, the pickup device includes a base, a rotating disc, a shooting component, and a driving component. The rotating disc is rotatably installed on the base, and the shooting component and the driving component are both installed on the base. During the assembly of the battery monomer 100, the shooting component is used to shoot 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 rotating disc to rotate so as to rotate the first current collector 4 to the standard angular position. Then, the pickup device places the first current collector 4 on the end of the first tab 32, at which time the battery monomer 100 can weld the first current collector 4 and the first tab 32 according to the pre-set welding track. For example, the pickup device can be a wire suction nozzle.

[0153] In some embodiments, the positioning hole 424 is a circular hole, the thickness of the region where the first current collector 4 is provided with the guide portion 42 is T, the diameter of the circular hole is d, and d = 4T-10T.

[0154] This embodiment designs the diameter d of the positioning hole 424 according to the thickness T of the region where the first current collector 4 is provided with the guide portion 42, 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.

[0155] In some embodiments, the ventilation portion 41 is a polygon, and the first end of the guide portion 42 close to the ventilation portion 41 is aligned with the corner region of the ventilation portion 41.

[0156] The ventilation portion 41 can be a triangle, a quadrilateral, etc. The corner region of the ventilation portion 41 is formed by the adjacent inner walls of the ventilation portion 41, and the corner region protrudes outward away from the ventilation portion 41.

[0157] This embodiment can cause stress concentration at the corner region of the ventilation portion 41 when the force acting on the first current collector 4 during thermal runaway of the battery monomer 100 and the release of internal gas, so as to tear the first current collector 4 from the corner region of the ventilation portion 41. The first end of the guide portion 42 close to the ventilation portion 41 is aligned with the corner region of the ventilation portion 41, so that the force generated by the tearing of the corner region can be further transmitted to the first end of the guide portion 42, so as to cause the first current collector 4 to deform or tear in the region of the guide portion 42. This can increase the ventilation area of the first current collector 4 during thermal runaway, reduce the blockage of the gas, improve the smoothness and efficiency of the exhaust, reduce the risk of fire and explosion caused by the incoordination of the pressure relief of the battery monomer 100, and improve the safety of the use of the battery monomer 100.

[0158] In some embodiments, the 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 one-to-one correspondence with the plurality of corners of the polygon.

[0159] As shown in FIG. 4, the vent portion 41 is a quadrilateral, and the guide portions 42 are provided in four and extend in the radial direction, and the first ends of the four guide portions 42 respectively correspond to the four corners of the quadrilateral.

[0160] In this embodiment, the guide portion 42 is provided at a position corresponding to each corner of the vent portion 41, and the stress concentration effect at each corner can be fully utilized to promote the further deformation or cracking of the first current collector 4 along the guide portion 42, thereby increasing the venting area of the first current collector 4 during thermal runaway and making the exhaust more smooth.

[0161] In some embodiments, as shown in FIG. 5, the first current collector 4 includes a shell connecting portion 44 and a tab connecting portion 43 having different base materials, the shell connecting portion 44 has the same base material as the first wall 12, the tab connecting portion 43 has the same base material as the first tab 32, and the vent portion 41 and the guide portion 42 are provided on the tab connecting portion 43.

[0162] The shell connecting portion 44 is connected around the outer periphery of the tab connecting portion 43, the tab connecting portion 43 is electrically connected to the first tab 32, the shell connecting portion 44 is electrically connected to the shell 1, the difference between the thermal expansion coefficients of the materials of the shell connecting portion 44 and the shell 1 does not exceed a preset threshold value, and the vent portion 41 and the guide portion 42 are both provided on the tab connecting portion 43.

[0163] For example, the first wall 12 includes a steel material, and the first tab 32 includes a copper material. If the first current collector 4 is made of copper material as a whole, after the first wall 12 is welded to the first current collector 4, the contraction degrees of the two materials are inconsistent due to the large difference between the thermal expansion coefficients of the first wall 12 and the first current collector 4 when cooled, which can easily cause welding cracks and liquid leakage problems, affecting the reliability of the battery monomer 100.

[0164] In this application, the tab connecting portion 43 can include a copper material, and the shell connecting portion 44 can include at least one of a steel material and a nickel material. In order to prevent rust, the tab connecting portion 43 and the shell connecting portion 44 made of steel material can be nickel-plated. In this way, the difference between the thermal expansion coefficients of the tab connecting portion and the shell 1 is small, and cracks are not easily generated.

[0165] As shown in FIG. 5, the tab connecting portion 43 and the shell connecting portion 44 can be butted in the radial direction and fixed by welding. Alternatively, as shown in FIG. 5, the tab connecting portion 43 and the shell connecting portion 44 are stacked in the thickness direction, the tab connecting portion 43 is disc-shaped, the shell connecting portion 44 is ring-shaped, in the height direction of the battery monomer 100, the shell connecting portion 44 is located on the side of the tab connecting portion 43 close to the pressure relief component 2, and the radial outer end of the shell connecting portion 44 exceeds the outer edge of the tab connecting portion 43. The vent portion 41 and the guide portion 42 are both arranged on the tab connecting portion 43, and the guide portion 42 is located radially inward of the inner edge of the shell connecting portion 44. The thickness of the tab connecting portion 43 and the shell connecting portion 44 can be kept consistent, facilitating welding.

[0166] In this embodiment, after the first wall 12 is welded with the first current collector 4, since the difference between the thermal expansion coefficients of the material of the shell connecting portion 44 and the material of the first wall 12 does not exceed the preset threshold, the two materials do not shrink to the same extent when cooled, which is likely to cause welding cracks, and can prevent liquid leakage and improve the reliability of the battery monomer 100 in operation.

[0167] In some embodiments, the tab connecting portion 43 is welded with the first tab 32 to form a welding mark, and the welding mark and the guide portion 42 are circumferentially spaced apart.

[0168] In this embodiment, the welding mark can be formed by laser welding. For a wound electrode assembly 3, the first tab 32 is a multi-layer tab. In order to reliably weld each layer of the tab, at least part of the welding mark can extend in the radial direction of the first current collector 4. The first current collector 4 can be circumferentially spaced apart by multiple welding marks, and the welding marks and the guide portion 42 are circumferentially spaced apart.

[0169] In this embodiment, the welding mark and the guide portion 42 are circumferentially spaced apart, which can prevent heat generated during welding from damaging the guide portion 42, so as to ensure the structural strength of the first current collector 4 in normal use.

[0170] In some embodiments, as shown in FIG. 3, the shell 1 includes a shell body 10 and an end cover 12', the shell body 10 has an opening, the end cover 12' closes the opening, and the first wall 12 is the end cover 12' or a bottom wall 13 of the shell body 10.

[0171] In FIG. 3, the side wall 11 and the bottom wall 13 can be integrally formed, the end of the side wall 11 away from the bottom wall 13 has an opening, the first wall 12 is the end cover 12', the end cover 12' is connected to the side wall 11 by welding or the like, and the pressure relief component 2 is arranged on the end cover 12'. Alternatively, the pressure relief component 2 is arranged on the bottom wall 13 of the shell body 10.

[0172] In this embodiment, the shell 1 is formed by connecting the shell body 10 and the end cover 12', which can facilitate the installation of the internal structure.

[0173] In some embodiments, the first wall 12 is an end cover 12', the bottom wall 13 is provided with an electrode terminal 6, the electrode terminal 6 is insulated from the bottom wall 13; the electrode assembly 3 further comprises a second tab 33, the second tab 33 is led out from the other end of the electrode body 31, the second tab 33 is opposite in polarity to the first tab 32, the battery monomer 100 further comprises a second current collector 5, the second current collector 5 is configured to electrically connect the second tab 33 and the electrode terminal 6.

[0174] The end cover 12' can serve as a first electrode lead-out part, and the electrode terminal 6 can protrude from the bottom wall 13, which serves as a second electrode lead-out part. The first electrode lead-out part and the second electrode lead-out part are opposite in polarity. Generally, the electrode terminal 6 is positive, and the end cover 12' is negative.

[0175] 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 "electrically connected" mentioned here can be achieved by welding, such as laser welding. The second current collector 5 can also adopt a sheet structure, for example, a sheet with uniform thickness, or a sheet with concave-convex or bending structures on part of the sheet. For a cylindrical battery monomer 100, the second current collector 5 can be disc-shaped.

[0176] The battery monomer 100 of this embodiment has the electrode terminal 6 arranged at the end away from the pressure relief component 2. When thermal runaway occurs, the discharge will be sprayed from the end where the pressure relief component 2 is located, away from the electrode terminal 6, and thus away from the busbar for electrically connecting the plurality of battery monomers 100, thereby reducing the impact on the electrical connection of the battery monomers 100 when thermal runaway occurs.

[0177] In some specific embodiments, as shown in FIGS. 1-5, the battery monomer 100 comprises an outer shell 1, an electrode assembly 3, a first current collector 4, a second current collector 5, and an electrode terminal. The outer shell 1 comprises a shell 10 and an end cover 12', the end cover 12' is used to close the opening of the shell 10, the shell 10 comprises a side wall 11 and a bottom wall 13, the bottom wall 13 is located at the end away from the end cover 12', the end cover 12' serves as the first wall 12, and the pressure relief component 2 is arranged on the end cover 12'; the electrode terminal 6 is arranged on the bottom wall 13. The end cover 12' serves as a first electrode lead-out part, and the electrode terminal 6 serves as a second electrode lead-out part and is insulated from the bottom wall 13.

[0178] The electrode assembly 3 is arranged in the outer shell 1, the electrode assembly 3 comprises an electrode body 31 and a first tab 32 and a second tab 33, the first tab 32 and the second tab 33 are led out from two ends of the electrode body 31 respectively, 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.

[0179] The first current collector 4 includes a tab connecting portion 43 and a case connecting portion 44 which are stacked in the thickness direction, the tab connecting portion 43 is in a disc shape, the case connecting portion 44 is in a ring shape, the case connecting portion 44 is located on the side of the tab connecting portion 43 close to the pressure relief component 2, and the radially outer end of the case connecting portion 44 exceeds the outer edge of the tab connecting portion 43. The vent portion 41 and the guide portion 42 are both provided on the tab connecting portion 43, the vent portion 41 is provided in the central region of the first current collector 4, and the at least one guide portion 42 includes a plurality of guide portions 42 which are uniformly arranged in the circumferential direction, each of the guide portions 42 extends in the radial direction, for example, four guide portions 42 are provided, the second end of each of the two opposite second guide portions 422 is provided with a positioning hole 424, and the first end of each of the two second guide portions 422 has a predetermined spacing portion 423 with the side wall of the vent portion 41; the first end of each of the two opposite first guide portions 421 is in communication with the vent portion 41, and the second end is not provided with a positioning hole 424. The length of the second guide portion 422 can be less than the length of the first guide portion 421.

[0180] Although the present application has been described with reference to the preferred embodiments, various modifications can be made to it without departing from the scope of the application, and equivalent components can be substituted therefor. In particular, the technical features mentioned in each of the embodiments can be combined in any manner as long as there is no structural conflict. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A battery cell, characterized by, The application relates to a battery, comprising: a housing (1) comprising a first wall (12) provided with a pressure relief component (2); an electrode assembly (3) provided in the housing (1), the electrode assembly (3) comprising an electrode body (31) and a first tab (32) extending from one end of the electrode body (31); and a first current collector (4) configured to electrically connect the first tab (32) and the housing (1), the first current collector (4) being at least partially located between the first tab (32) and the pressure relief component (2), the first current collector (4) being provided with at least one vent (41) and at least one guide (42), the vent (41) penetrating the first current collector (4) along the thickness direction of the first wall (12), and the guide (42) being provided in the peripheral region of the vent (41). The guide (42) comprises at least one of a through hole (42A) or a notch (42B).

2. The battery cell of claim 1, wherein, The guide (42) extends along the radial direction of the first current collector (4).

3. The battery cell according to claim 1 or 2, characterized in that, The at least one guide (42) comprises a first guide (421) in communication with the vent (41) near the first end of the vent (41).

4. The battery cell according to any one of claims 1 to 3, characterized in that Two first guides (421) are located on the same straight line, and both of the two first guides (421) are in communication with the vent (41) near the first end of the vent (41).

5. The battery cell of claim 4, wherein, The at least one guide (42) comprises a second guide (422), and a preset interval (423) is provided between the second guide (422) and the side wall of the vent (41) near the first end of the vent (41).

6. The battery cell according to any one of claims 1 to 5, characterized in that Two second guides (422) are located on the same straight line, and both of the two second guides (422) are provided with a preset interval (423) between the first end and the side wall of the vent (41).

7. The battery cell of claim 6, wherein, The preset interval (423) is configured to be damaged when the air pressure in the housing (1) exceeds a preset threshold.

8. The battery cell according to claim 6 or 7, characterized in that The length (X) of the preset interval (423) is less than 15 mm, and the thickness of the preset interval (423) is less than 2 mm.

9. The battery cell according to any one of claims 6 to 8, characterized in that A plurality of guides (42) are arranged at intervals in the circumferential direction of the first current collector (4).

10. The battery cell according to any one of claims 1 to 9, characterized in that A plurality of guides (42) are arranged in a central symmetry with respect to the center of the first current collector (4).

11. The battery cell of claim 10, wherein, The distance between the second ends of two guides (42) located on the same straight line away from the vent (41) is L, the maximum radial dimension of the first current collector (4) is D, and L=0.1D-0.8D.

12. The battery cell of claim 11, wherein, The thickness of the region of the first current collector (4) where the guide (42) is located is T, and the width of the guide (42) is W, W=T-5T.

13. The battery cell of claim 12, wherein, The first current collector (4) is provided with a positioning hole (424) at the second end away from the vent (41).

14. The battery cell according to any one of claims 1 to 13, characterized in that ​ 15. The battery cell of claim 14, wherein, The at least one guide portion (42) comprises a plurality of guide portions (42) extending along the radial direction of the first current collector (4), two of the plurality of guide portions (42) are located on the same straight line, and the positioning hole (424) is provided in two, and the two positioning holes (424) are respectively arranged at the second ends of the two guide portions (42) on the same straight line.

16. The battery cell of claim 15, wherein, The positioning hole (424) is a circular hole, the thickness of the area where the guide portion (42) is arranged on the first current collector (4) is T, and the diameter of the circular hole is d, d=4T~10T.

17. The battery cell of any one of claims 1-16, wherein, The vent portion (41) is a polygon, and 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).

18. The battery cell of claim 17, wherein, The guide portion (42) is provided in a plurality, and the number of the guide portion (42) is consistent with the number of the corners of the polygon, and the plurality of guide portions (42) are arranged one by one corresponding to the plurality of corners of the polygon.

19. The battery cell of any one of claims 1-18, wherein, The first current collector (4) comprises a shell connecting portion (44) and a tab connecting portion (43) with different base materials, the shell connecting portion (44) has the same base material as the first wall (12), the tab connecting portion (43) has the same base material as the first tab (32), and the vent portion (41) and the guide portion (42) are arranged on the tab connecting portion (43).

20. The battery cell of any one of claims 1-19, wherein, The tab connecting portion (43) is welded with the first tab (32) to form a welding mark, and the welding mark is arranged in a circumferential direction with the guide portion (42).

21. The battery cell of any one of claims 1-20, wherein, The vent portion (41) is arranged in the central area of the first current collector (4).

22. The battery cell of any one of claims 1-21, wherein, The shell (1) comprises a shell body (10) and an end cover (12'), the shell body (10) has an opening, the end cover (12') closes the opening, and the first wall (12) is the end cover (12') or the bottom wall (13) of the shell body (10).

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

24. A battery comprising the battery monomer (100) of any one of claims 1-23.

25. A power consuming device comprising the battery monomer (100) of any one of claims 1-23 and / or the battery (200) of claim 24, for providing electric energy for the power consuming device.

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