Battery cell, battery device and electric device

Abstract

The utility model discloses a battery monomer, a battery device and a power utilization device. Each single battery comprises an electrode assembly, a current collecting disc, a shell and a sealing piece, and the electrode assembly is provided with a tab; the collector plate is welded with the tab; the electrode assembly and the current collecting disc are located in the shell, the shell is provided with a first step and a second step in the height direction of the single battery, the second step is located on the side, away from the electrode assembly, of the first step, and the current collecting disc is welded to the first step; the sealing piece is connected with the second step, and the sealing piece covers a first welding area of the flow collecting disc and the first step. According to the invention, the probability of exposure of the welding mark of the first welding area is reduced, so that the liquid leakage risk of the battery monomer is reduced, and the reliability of the battery monomer is improved.

Description

Technical Field

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

[0002] Battery cells are widely used in electronic devices such as mobile phones, laptops, electric bicycles, electric cars, electric airplanes, electric boats, electric toy cars, electric toy boats, electric toy airplanes, and power tools. Battery cells can include nickel-cadmium battery cells, nickel-metal hydride battery cells, lithium-ion battery cells, and secondary alkaline zinc-manganese battery cells.

[0003] In the development of battery technology, how to improve the reliability of battery devices is an important research direction in battery technology. Utility Model Content

[0004] Embodiments of the present application provide a battery cell, a battery device, and an electrical device, which can improve the reliability of the battery device.

[0005] In the first aspect, an embodiment of the present application provides a battery cell, which includes an electrode assembly, a current collecting plate, a shell and a seal, wherein the electrode assembly is provided with a pole tab; the current collecting plate is welded to the pole tab; the electrode assembly and the current collecting plate are located inside the shell, and along the height direction of the battery cell, the shell is provided with a first step and a second step, the second step is located on the side of the first step away from the electrode assembly, and the current collecting plate is welded to the first step; the seal is connected to the second step, and the seal covers the first welding area between the current collecting plate and the first step.

[0006] In the above solution, by arranging the first step and the second step on the shell, the seal is connected to the second step and covers the first welding area between the collecting plate and the first step, thereby reducing the probability of the weld mark of the first welding area being exposed, thereby reducing the risk of leakage of the battery cell and improving the reliability of the battery cell.

[0007] In some embodiments, the second step includes a first sidewall facing the seal, and the first sidewall is welded to the outer periphery of the seal.

[0008] In the above solution, by welding the first side wall of the second step to the sealing member, the overall welding area can be reduced, thereby reducing the possibility of welding defects.

[0009] In some embodiments, the battery cell further includes a third step, and the third step is disposed on a side of the second step facing away from the first step.

[0010] In the above solution, by providing the third step, it is possible to prevent the molten pool after welding the seal to the second step from protruding higher than the outer surface of the shell to a certain extent, thereby improving the flatness of the outer surface of the shell.

[0011] In some embodiments, the seal includes a main body and an abutment portion, and there is a gap between the main body and the first step; the abutment portion is arranged along the outer periphery of the main body, the abutment portion contacts the first step toward the side of the electrode assembly, and the abutment portion is connected to the second step.

[0012] In the above solution, by setting a certain gap between the first step and the main body of the seal, space can be provided for the thickness change caused by welding the collecting plate and the first step, which can prevent the main body from being squeezed and deformed outward after welding to a certain extent.

[0013] In some embodiments, in the height direction, a projection of the first welding area is within a projection range of the main body.

[0014] In the above solution, by limiting the first welding area within the range of the main body, it is possible to prevent thickness changes after welding the collecting plate and the first step, which would squeeze the abutting portion outward and cause the surface of the abutting portion to be uneven.

[0015] In some embodiments, the shell is provided with a liquid injection hole that passes through the first step and the second step in sequence, and the sealing member seals the liquid injection hole.

[0016] In the above solution, the liquid injection hole and the first welding area are sealed simultaneously by the sealing member, which simplifies the structure and improves the integration of the battery cell.

[0017] In some embodiments, a through hole corresponding to the liquid injection hole is opened on the collecting plate, and in the height direction, the projected area of the liquid injection hole is smaller than the projected area of the through hole.

[0018] In the above solution, by setting the projected area of the injection hole to be smaller than the projected area of the collecting plate through hole, the phenomenon of the collecting plate covering the injection hole due to assembly error can be prevented to a certain extent when assembling the electrode assembly and the shell.

[0019] In some embodiments, the battery cell further includes a pressure relief mechanism, which is disposed on a side of the seal away from the electrode assembly, thereby simplifying the mechanism and improving the integration of the battery cell.

[0020] In some embodiments, the material of the seal is the same as that of the housing, which can facilitate the preparation of the battery cell and save costs.

[0021] In a second aspect, an embodiment of the present application further provides a battery device comprising a battery cell according to any of the above embodiments.

[0022] In a third aspect, an embodiment of the present application further provides an electrical device comprising the above-mentioned battery device.

[0023] The above description is only an overview of the technical solution of this application. In order to more clearly understand the technical means of this application, it can be implemented in accordance with the contents of the specification. In order to make the features and advantages of this application more obvious and easy to understand, the specific implementation methods of this application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following briefly introduces the drawings required for use in the embodiments of the present application. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0025] Figure 1 A schematic structural diagram of a vehicle according to some embodiments of the present application;

[0026] Figure 2 This is a schematic structural diagram of a battery device according to some embodiments of the present application;

[0027] Figure 3 This is a schematic structural diagram of a battery module according to some embodiments of the present application;

[0028] Figure 4 This is a schematic structural diagram of a battery cell in some embodiments of the present application;

[0029] Figure 5 Schematic cross-sectional view of a battery cell according to some embodiments of the present application;

[0030] Figure 6 for Figure 5 A magnified schematic diagram of point A;

[0031] Figure 7 This is a partial cross-sectional schematic diagram of a battery cell according to some embodiments of the present application.

[0032] Description of Figure Numbers:

[0033] 1000, vehicle; 100, battery device; 200, controller; 300, motor; 10, upper cover; 30, housing; 400, battery module; 20, battery cell; 22, housing; 221, first step; 222, second step; 223, third step; 224, first side wall; 225, injection hole; 21, end cover; 23, electrode assembly; 231, tab; 26, electrode terminal; 27, collecting plate; 271, through hole; 28, seal; 281, main body; 282, abutment portion; S1, first welding area; S2, second welding area; 29, pressure relief mechanism; X, height direction. DETAILED DESCRIPTION

[0034] The following detailed description of the embodiments of the present application is provided in conjunction with the accompanying drawings and examples. The following detailed description of the embodiments and the accompanying drawings are used to illustrate the principles of the present application, but are not intended to limit the scope of the present application, that is, the present application is not limited to the described embodiments.

[0035] In the description of this application, it should be noted that, unless otherwise specified, "multiple" means more than two; the terms "upper", "lower", "left", "right", "inside", "outside", etc., indicating directions or positional relationships, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation on this application. In addition, the terms "first", "second", "third", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance. "Vertical" is not strictly perpendicular, but is within the allowable error range. "Parallel" is not strictly parallel, but is within the allowable error range.

[0036] References to "embodiments" in this application mean that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described in this application may be combined with other embodiments.

[0037] The directional words appearing in the following description are all directions shown in the figures, and do not limit the specific structure of this application. In the description of this application, it should also be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected or indirectly connected through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to the specific circumstances.

[0038] In this application, battery cells may include, but are not limited to, lithium-ion secondary batteries, lithium-ion primary batteries, lithium-sulfur batteries, sodium-lithium-ion batteries, sodium-ion batteries, or magnesium-ion batteries. Battery cells may be cylindrical, flat, rectangular, or other shapes. Battery cells are generally categorized into three types based on packaging: cylindrical, prismatic, and pouch-type.

[0039] The battery device mentioned in the embodiments of the present application may include one or more battery cell assemblies for providing voltage and capacity. The battery cell assembly may include multiple battery cells, which are connected in series, parallel, or hybrid via a busbar.

[0040] In some embodiments, a battery cell assembly is typically formed by arranging multiple battery cells. For example, the battery cell assembly may be a battery module, which is formed by arranging and securing multiple battery cells to form a single module. For example, a battery module may be formed by bundling multiple battery cells using cable ties.

[0041] In some embodiments, the battery device may be a battery pack, which includes a case and one or more battery cell assemblies, wherein the battery cell assemblies are housed in the case.

[0042] As an example, the battery cell assembly may be a battery module, and the battery cell assembly may be accommodated in the box by fixing the battery module in the box.

[0043] As an example, the battery cell assembly may also be housed in the box by directly fixing the plurality of battery cells to the box.

[0044] A battery cell includes an electrode assembly and an electrolyte. The electrode assembly consists of a positive electrode sheet, a negative electrode sheet, and a separator. A battery cell primarily operates by the movement of metal ions between the positive and negative electrode sheets. The positive electrode sheet comprises a positive current collector and a positive active material layer. The positive active material layer is coated on the surface of the positive current collector. The current collector uncoated with the positive active material layer protrudes from the current collector coated with the positive active material layer. The current collectors uncoated with the positive active material layer, when stacked, serve as the positive electrode tabs. For lithium-ion batteries, for example, the positive current collector can be made of aluminum, and the positive active material can be lithium cobalt oxide, lithium iron phosphate, ternary lithium, or lithium manganese oxide. The negative electrode sheet comprises a negative current collector and a negative active material layer. The negative active material layer is coated on the surface of the negative current collector. The current collector uncoated with the negative active material layer protrudes from the current collector coated with the negative active material layer. The current collectors uncoated with the negative active material layer, when stacked, serve as the negative electrode tabs. The negative current collector can be made of copper, and the negative active material can be carbon, silicon, or other materials. The material of the isolation film may be PP (polypropylene) or PE (polyethylene), etc. In addition, the electrode assembly may be a wound structure or a laminated structure, but the embodiments of the present application are not limited thereto.

[0045] The present invention provides an electrical device that uses a battery device as a power source. The electrical device may include, but is not limited to, a mobile phone, a tablet, a laptop computer, an electric toy, an electric tool, a battery-powered vehicle, an electric car, a ship, a spacecraft, and the like. The electric toy may include a fixed or mobile electric toy, such as a game console, an electric car toy, an electric ship toy, and an electric airplane toy. The spacecraft may include an airplane, a rocket, a space shuttle, and a spacecraft.

[0046] For cylindrical battery cells, the bottom of the shell is generally used as the negative electrode. After welding the negative electrode tab of the electrode assembly to the current collecting plate, the electrode assembly and the current collecting plate are placed in the shell. From the outside of the bottom of the shell, the bottom of the shell and the current collecting plate are welded by penetration welding. The welding marks are exposed to the outside. If there are welding defects, it is easy to cause the risk of electrolyte leakage, which reduces the reliability of the battery cell.

[0047] In order to solve the above technical problems, an embodiment of the present application provides a battery cell, which includes an electrode assembly, a current collecting plate, a shell and a seal, and the electrode assembly is provided with a pole ear; the current collecting plate is welded to the pole ear; the electrode assembly and the current collecting plate are located inside the shell, and along the height direction X of the battery cell, the shell is provided with a first step and a second step, the second step is located on the side of the first step away from the electrode assembly, and the current collecting plate is welded to the first step; the seal is connected to the second step, and the seal covers the first welding area between the current collecting plate and the first step, reducing the probability of the weld mark of the first welding area being exposed, thereby reducing the risk of leakage of the battery cell and improving the reliability of the battery cell.

[0048] The present invention provides an electric device that uses a battery as a power source. The electric device may be, but is not limited to, a mobile phone, a tablet, a laptop computer, an electric toy, an electric tool, a battery-powered vehicle, an electric car, a ship, a spacecraft, etc. The electric toy may include a fixed or mobile electric toy, such as a game console, an electric car toy, an electric ship toy, and an electric airplane toy, etc. The spacecraft may include an airplane, a rocket, a space shuttle, and a spacecraft, etc.

[0049] For the convenience of description, the following embodiments are described by taking a vehicle 1000 as an example of an electrical device according to an embodiment of the present application.

[0050] Please refer to Figure 1 , Figure 1 A schematic structural diagram of a vehicle 1000 provided for some embodiments of the present application. The vehicle 1000 may be a fuel vehicle, a gas vehicle or a new energy vehicle. The new energy vehicle may be a pure electric vehicle, a hybrid vehicle or an extended-range vehicle, etc. A battery device 100 is provided inside the vehicle 1000. The battery device 100 may be provided at the bottom, head or tail of the vehicle 1000. The battery device 100 may be used to power the vehicle 1000. For example, the battery device 100 may serve as an operating power source for the vehicle 1000. The vehicle 1000 may further include a controller 200 and a motor 300. The controller 200 is used to control the battery device 100 to power the motor 300, for example, for starting, navigating and operating power requirements of the vehicle 1000 during driving.

[0051] In some embodiments of the present application, the battery device 100 can serve not only as an operating power source for the vehicle 1000 , but also as a driving power source for the vehicle 1000 , replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000 .

[0052] Please refer to Figure 2 , Figure 2 Schematic diagram of the structure of a battery device provided in some embodiments of the present application. The battery device 100 includes a battery box and a battery cell 20. In some embodiments, the battery box may include an upper cover 10a and a box body 10b, the upper cover 10a and the box body 10b covering each other, and the upper cover 10a and the box body 10b together define a storage space for accommodating the battery cell 20. The box body 10b may be a hollow structure with one end open, and the upper cover 10a may be a plate-like structure, and the upper cover 10a covers the open side of the box body 10b, so that the upper cover 10a and the box body 10b together define a storage space; the upper cover 10a and the box body 10b may also be hollow structures with one side open, and the open side of the upper cover 10a covers the open side of the box body 10b. Of course, the box body 10 formed by the upper cover 10a and the box body 10b can be of various shapes, such as a cylinder, a rectangular parallelepiped, etc.

[0053] Figure 3 A schematic structural diagram of a battery module 400 provided for some embodiments of the present application. In the battery device 100, there may be multiple battery cells 20, and the multiple battery cells 20 may be connected in series, in parallel, or in mixed connection. Mixed connection means that the multiple battery cells 20 are both connected in series and in parallel. The multiple battery cells 20 may be directly connected in series, in parallel, or in mixed connection, and then the whole formed by the multiple battery cells 20 may be accommodated in the case 10; of course, the battery device 100 may also be in the form of a battery module 400 in which multiple battery cells 20 are first connected in series, in parallel, or in mixed connection, and the multiple battery modules 400 are then connected in series, in parallel, or in mixed connection to form a whole, and accommodated in the case 10. The battery device 100 may also include other structures. For example, the battery device 100 may also include a busbar component for realizing electrical connection between the multiple battery cells 20.

[0054] Each battery cell 20 may be a secondary battery or a primary battery; it may also be a lithium-sulfur battery, a sodium-ion battery or a magnesium-ion battery, but is not limited thereto.

[0055] Please refer to Figure 4 , Figure 4 The following is a schematic diagram of the decomposition structure of a battery cell 20 provided in some embodiments of the present application. A battery cell 20 is the smallest unit that makes up a battery. Figure 3 The battery cell 20 includes an end cap 21, a shell 22, an electrode assembly 23 and other functional components.

[0056] The end cap 21 is a component that covers the opening of the housing 22 to isolate the internal environment of the battery cell 20 from the external environment. The shape of the end cap 21 can be adapted to the shape of the housing 22 to fit the housing 22. Optionally, the end cap 21 can be made of a material with a certain hardness and strength (such as an aluminum alloy). This prevents the end cap 21 from deforming when subjected to compression or collision, thereby providing the battery cell 20 with greater structural strength and improved safety. Functional components such as electrode terminals 26 can be provided on the end cap 21. The electrode terminals 26 can be used to electrically connect to the electrode assembly 23 to output or input electrical energy to the battery cell 20. In some embodiments, the end cap 21 can also be provided with a pressure relief mechanism for relieving internal pressure when the internal pressure or temperature of the battery cell 20 reaches a threshold. The end cap 21 can also be made of a variety of materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., and this embodiment of the present application does not impose any specific limitations on this. In some embodiments, an insulating member may be provided inside the end cap 21 to isolate the electrical connection components in the housing 22 from the end cap 21 to reduce the risk of short circuit. For example, the insulating member may be made of plastic, rubber, or the like.

[0057] The shell 22 is a component used to cooperate with the end cap 21 to form the internal environment of the battery cell 20. The internal environment formed can be used to accommodate the electrode assembly 23, electrolyte and other components. The shell 22 and the end cap 21 can be independent components. An opening can be set on the shell 22, and the internal environment of the battery cell 20 is formed by covering the opening with the end cap 21. In some examples, the shell 22 is a hollow structure with an opening on one side, and the end cap 21 is a single end cap that covers the opening of the shell 22. In other examples, the shell 22 is a hollow structure with openings on both sides, and there are two end caps 21, and the two end caps 21 respectively cover the two openings of the shell 22. Without limitation, the end cap 21 and the shell 22 can also be integrated. Specifically, the end cap 21 and the shell 22 can form a common connection surface before other components are inserted into the shell. When the interior of the shell 22 needs to be encapsulated, the end cap 21 is then covered with the shell 22. Specifically, the shell 22 is cylindrical and can be made of a variety of materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., and the embodiment of the present application does not impose any special restrictions on this.

[0058] The electrode assembly 23 is a component in the battery cell 20 where electrochemical reactions occur. One or more electrode assemblies 23 may be contained in the housing 22. The electrode assembly 23 is mainly formed by winding a positive electrode sheet and a negative electrode sheet, and a separator is usually provided between the positive electrode sheet and the negative electrode sheet. The parts of the positive electrode sheet and the negative electrode sheet with active materials constitute the main body of the electrode assembly 23, and the parts of the positive electrode sheet and the negative electrode sheet without active materials each constitute a tab. The positive electrode tab and the negative electrode tab may be located together at one end of the main body or respectively at both ends of the main body. During the charge and discharge process of the battery, the positive electrode active material and the negative electrode active material react with the electrolyte, and the tabs are connected to the electrode terminals 26 to form a current loop.

[0059] Figure 5 Schematic cross-sectional view of a battery cell according to some embodiments of the present application; Figure 6 for Figure 5 A magnified schematic diagram of .

[0060] Please refer to Figure 5 and Figure 6 In the first aspect, an embodiment of the present application provides a battery cell 20, which includes an electrode assembly 23, a current collecting plate 27, a shell 22 and a seal 28. The electrode assembly 23 is provided with a pole ear 231; the current collecting plate 27 is welded to the pole ear 231; the electrode assembly 23 and the current collecting plate 27 are located inside the shell 22, and in the height direction X along the battery cell 20, the shell 22 is provided with a first step 221 and a second step 222, the second step 222 is located on the side of the first step 221 away from the electrode assembly 23, and the current collecting plate 27 is welded to the first step 221; the seal 28 is connected to the second step 222, and the seal 28 covers the first welding area S1 between the current collecting plate 27 and the first step 221.

[0061] The current collecting plate 27 refers to a conductive structure that connects the shell 22 and the tab 231 to achieve current flow between the shell 22 and the tab 231. The tab 231 is provided at the end of the electrode assembly 23. During assembly, the tab 231 is first welded to the current collecting plate 27, and then the electrode assembly 23 and the current collecting plate 27 are placed inside the shell 22. Then, the first step 221 of the shell 22 is welded to the current collecting plate 27 from the outside of the shell 22. For example, when the shell 22 serves as the negative electrode of the battery cell 20, the tab 231 is the negative electrode tab 231. Of course, it is not ruled out that some battery cells 20 use the shell 22 as the positive electrode, in which case the tab 231 is the positive electrode tab 231.

[0062] The housing 22 can be formed of materials such as aluminum alloy and steel. The housing 22 can include a bottom wall and a side wall surrounding the bottom wall. A first step 221 and a second step 222 are provided on the bottom wall of the housing 22. The second step 222 is provided to protrude outward from the housing 22 relative to the first step 221.

[0063] The seal 28 can be connected to the second step 222 by welding, bolts, clamping, etc. The seal 28 can be made of the same material as the housing 22, such as aluminum alloy, steel, etc., or can be made of other materials different from the housing 22.

[0064] The first weld area S1 is the area where the weld mark is formed between the current collecting plate 27 and the first step 221. The seal 28 covers the first weld area S1, meaning that the projection of the first weld area S1 along the height direction X of the battery cell 20 is within the projection range of the seal 28, preventing the first weld area S1 from leaking out and sealing and protecting the first weld area S1 within the seal 28.

[0065] In the above solution, by setting the first step 221 and the second step 222 on the shell 22, the seal 28 is connected to the second step 222, and covers the first welding area S1 between the collecting plate 27 and the first step 221, thereby reducing the probability of the weld mark of the first welding area S1 being exposed, thereby reducing the risk of leakage of the battery cell 20 and improving the reliability of the battery cell 20.

[0066] In some embodiments, in the height direction X along the battery cell 20 , the thickness D1 of the first step 221 satisfies: 0.3 mm≦D1≦0.8 mm.

[0067] Optionally, the thickness D1 of the first step 221 may be any value between 0.3 mm and 0.8 mm. For example, D1 may be 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, or 0.8 mm.

[0068] The thickness of the first step 221 in the embodiment of the present application is within a moderate range, which can not only facilitate the welding of the two, but also ensure the welding strength between the first step 221 and the current collecting plate 27 to a certain extent.

[0069] Preferably, in the height direction X along the battery cell 20 , the thickness D1 of the first step 221 satisfies 0.3 mm ≤ D1 ≤ 0.5 mm.

[0070] Optionally, the thickness D1 of the first step 221 may be any value between 0.3 mm and 0.5 mm. For example, D1 may be 0.3 mm, 0.35 mm, 0.4 mm, 0.42 mm, 0.48 mm, or 0.5 mm.

[0071] The embodiment of the present application further facilitates the welding of the two and can ensure the welding strength between the first step 221 and the current collecting plate 27 to a certain extent.

[0072] Figure 7 This is a partial cross-sectional schematic diagram of a battery cell according to some embodiments of the present application.

[0073] like Figure 7 As shown, in some embodiments, the second step 222 includes a first side wall 224 facing the seal 28 , and the first side wall 224 is welded to the outer periphery of the seal 28 .

[0074] The second step 222 is retracted inward relative to the first step 221 , so that the second step 222 is shorter than the first step 221 , forming an accommodating space for accommodating the sealing member 28 .

[0075] The first side wall 224 faces the outer periphery of the seal 28, and the first side wall 224 of the second step 222 is welded to the seal 28 to form a second welding area S2. The second welding area S2 has the same shape as the outer periphery of the seal 28, and can be circular, elongated or square.

[0076] Compared with the prior art method of welding the tab 231 to the collecting plate 27 and then welding the shell 22 to the collecting plate 27 over a large area, the area of the second welding region S2 is significantly smaller, and even if leakage occurs, welding defects are relatively less.

[0077] In the above solution, by welding the first side wall 224 of the second step 222 to the sealing member 28 , the overall welding area can be reduced, thereby reducing the possibility of welding defects.

[0078] In some embodiments, the battery cell 20 further includes a third step 223 , which is disposed on a side of the second step 222 away from the first step 221 .

[0079] After welding the first sidewall 224 of the second step 222 to the seal 28, a molten pool protrusion may form in the second weld region S2. This molten pool protrusion is a raised shape on the surface of the molten pool. While this type of molten pool can ensure a more complete weld fill, it can also easily lead to weld protrusions and slag inclusions. Without the third step 223, the location of the molten pool protrusion would result in an uneven outer surface of the housing 22.

[0080] In the above solution, by providing the third step 223 , the molten pool after welding the seal 28 and the second step 222 can be prevented from protruding higher than the outer surface of the shell 22 to a certain extent, thereby improving the flatness of the outer surface of the shell 22 .

[0081] In some embodiments, the seal 28 includes a main body portion 281 and an abutment portion 282, and there is a gap between the main body portion 281 and the first step 221; the abutment portion 282 is arranged along the outer periphery of the main body portion 281, and the abutment portion 282 contacts the first step 221 toward one side of the electrode assembly 23, and the abutment portion 282 is connected to the second step 222.

[0082] Along the height direction X of the battery cell 20, the cross-section of the seal 28 is concave, with the main portion 281 recessed downward relative to the abutment portion 282, creating a gap, or space, between the main portion 281 and the first step 221. The current collecting plate 27 may become thicker after being welded to the first step 221, and this gap accommodates this increased thickness.

[0083] In the above solution, by setting a certain gap between the first step 221 and the main body 281 of the seal 28, space can be provided for the thickness change caused by welding the collecting plate 27 and the first step 221, which can prevent the main body 281 from being squeezed and deformed outward after welding to a certain extent.

[0084] In some embodiments, along the height direction X, the projection of the first welding region S1 is within the projection range of the main body portion 281 .

[0085] In the above solution, by limiting the first welding area S1 within the range of the main body 281, it can be prevented to a certain extent that the thickness change of the collecting plate 27 and the first step 221 after welding will not squeeze the abutting portion 282 outward, resulting in an uneven surface of the abutting portion 282.

[0086] In some embodiments, the housing 22 is provided with a liquid injection hole 225 that sequentially passes through the first step 221 and the second step 222 , and the sealing member 28 seals the liquid injection hole 225 .

[0087] The electrolyte is an important component of the battery cell 20. The electrolyte is generally injected into the housing 22 through the injection hole 225, so that the electrolyte penetrates into the electrode, participates in the chemical reaction, and realizes the conversion of chemical energy into electrical energy.

[0088] In the above solution, the sealing member 28 seals the liquid injection hole 225 and the first welding area S1 at the same time, which simplifies the structure and improves the integration of the battery cell 20.

[0089] In some embodiments, a through hole 271 corresponding to the liquid injection hole 225 is formed on the collecting plate 27 . In the height direction X, the projected area of the liquid injection hole 225 is smaller than the projected area of the through hole 271 .

[0090] That is, the size of the through hole 271 is larger than the size of the injection hole 225. For example, if the injection hole 225 and the through hole 271 are both circular and coaxial, the diameter of the injection hole 225 is smaller than the diameter of the through hole 271. Of course, the injection hole 225 and the through hole 271 can also be elliptical, rectangular, square, or other shapes.

[0091] In the above scheme, by setting the projected area of the injection hole 225 to be smaller than the projected area of the through hole 271 of the collecting plate 27, when assembling the electrode assembly 23 and the shell 22, the phenomenon of the collecting plate 27 covering the injection hole 225 due to assembly errors can be prevented to a certain extent.

[0092] In some embodiments, the battery cell 20 further includes a pressure relief mechanism 29 , which is disposed on a side of the seal 28 facing away from the electrode assembly 23 .

[0093] When the internal pressure or temperature of the battery cell 20 reaches a threshold, the internal gas of the battery cell 20 can pass through the through-hole 271 of the collecting plate 27 and the liquid injection hole 225 of the housing 22, and the internal pressure is released by the pressure relief mechanism 29. The surface of the pressure relief mechanism 29 can be flush with the surface of the third step 223. The pressure relief mechanism 29 can be connected to the seal 28 by means of a snap connection or bolts.

[0094] In the above solution, by arranging the pressure relief mechanism 29 on the side of the sealing member 28 away from the electrode assembly 23 , the mechanism is simplified and the integration of the battery cell 20 is improved.

[0095] In some embodiments, the material of the seal 28 is the same as that of the housing 22 , which can facilitate the preparation of the battery cell 20 and save costs.

[0096] In a second aspect, an embodiment of the present application further provides a battery device 100 , comprising a battery cell 20 according to any of the above embodiments.

[0097] In a third aspect, an embodiment of the present application further provides an electrical device, comprising the above-mentioned battery device 100 .

[0098] According to some embodiments of the present application, a battery cell 20 is provided. The battery cell 20 includes an electrode assembly 23, a current collecting plate 27, a housing 22, and a seal 28. The electrode assembly 23 is provided with a tab 231. The current collecting plate 27 is welded to the tab 231. The electrode assembly 23 and the current collecting plate 27 are located within the housing 22. In the height direction X of the battery cell 20, the housing 22 is provided with a first step 221 and a second step 222. The second step 222 is located on a side of the first step 221 facing away from the electrode assembly 23. The current collecting plate 27 is welded to the first step 221. The seal 28 is connected to the second step 222 and covers a first weld region S1 between the current collecting plate 27 and the first step 221. The battery cell 20 also includes a third step 223. The third step 223 is located on a side of the second step 222 facing away from the first step 221.

[0099] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some or all of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application, and they should all be included in the scope of the claims and specification of the present application. In particular, as long as there is no structural conflict, the various technical features mentioned in the various embodiments can be combined in any way. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions that fall within the scope of the claims.

Claims

1. A battery cell, characterized in that: include: An electrode assembly, wherein the electrode assembly is provided with a tab; A current collecting plate, welded to the tab; The housing includes a first step and a second step located on a side of the first step away from the electrode assembly, and the current collecting plate is welded to the first step. A sealing member is connected to the second step, and covers a first welding area between the collecting plate and the first step.

2. The battery cell according to claim 1, wherein: The second step includes a first side wall facing the sealing member, and the first side wall is welded to the outer periphery of the sealing member.

3. The battery cell according to claim 2, characterized in that: The battery cell further includes a third step, and the third step is disposed on a side of the second step away from the first step.

4. The battery cell according to claim 1, wherein: The sealing member comprises: a main body portion, wherein a gap is formed between the main body portion and the first step; The abutting portion is provided along the outer periphery of the main body portion, the abutting portion contacts the first step on a side facing the electrode assembly, and the abutting portion is connected to the second step.

5. The battery cell according to claim 4, characterized in that In the height direction, a projection of the first welding area is within a projection range of the main body portion.

6. The battery cell according to claim 1, characterized in that The shell is provided with a liquid injection hole which passes through the first step and the second step in sequence, and the sealing member seals the liquid injection hole.

7. The battery cell according to claim 6, characterized in that The collecting plate is provided with a through hole corresponding to the liquid injection hole, and along the height direction, the projected area of the liquid injection hole is smaller than the projected area of the through hole.

8. The battery cell according to claim 1, wherein: The battery cell further includes a pressure relief mechanism, which is disposed on a side of the seal away from the electrode assembly.

9. The battery cell according to claim 1, characterized in that The material of the sealing member is the same as that of the housing.

10. A battery device, characterized in that: The invention comprises a battery cell according to any one of claims 1 to 9.

11. An electrical device, characterized in that: A battery device comprising the battery device of claim 10.

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