Battery cell, battery, and electrical device

Abstract

A battery cell (12), a battery (100), and an electrical device. The battery cell (12) comprises a casing (121), pressure relief mechanisms (123), and an electrode assembly (122). The casing (121) has a first end wall (1211) and a side wall (1212), and the side wall (1212) surrounds the first end wall (1211); the first end wall (1211) comprises a body (12111) and protruding portions (12112), and the protruding portions (12112) protrude from the inner surface of the body (12111); the pressure relief mechanisms (123) are arranged on the body (12111); the electrode assembly (122) is accommodated in the casing (121); the electrode assembly (122) comprises a main body (1221) and a first tab (1222), and the first tab (1222) is arranged on one end of the main body (1221); a first gap (124) is formed between the outer peripheral surface of the main body (1221) and the inner surface of the side wall (1212); the first current collector (125) is located between the first end wall (1211) and the electrode assembly (122), the protruding portions (12112) are connected to the first current collector (125), a second gap (126) is formed between the body (12111) and the first current collector (125) in the thickness direction of the first end wall (1211), and the first gap (124) is in communication with the second gap (126). The pressure relief mechanisms (123) can maintain an unobstructed connection with the first gap (124), such that when the battery cell (12) undergoes thermal runaway, the gas inside the battery cell (12) can promptly reach the pressure relief mechanisms (123) and be discharged, thereby improving the reliability of the battery cell (12).

Description

Battery cells, batteries and electrical equipment

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to Chinese patent application No. 202410039681.6, filed on January 10, 2024, entitled “Battery Cell, Battery and Electrical Equipment,” the entire contents of which are incorporated herein by reference. Technical Field

[0003] The present application relates to the field of battery technology, and in particular to a battery cell, a battery, and an electrical device. Background Art

[0004] Energy conservation and emission reduction are key to the sustainable development of the automotive industry. Electric vehicles, due to their energy-saving and environmentally friendly advantages, have become an important component of the sustainable development of the automotive industry. For electric vehicles, battery technology is a key factor in their development.

[0005] How to improve the reliability of battery cells is an urgent problem to be solved in battery technology.

[0006] Summary of the Invention

[0007] In view of the above problems, the present application provides a battery cell, a battery and an electrical device, which can improve the reliability of the battery cell.

[0008] In a first aspect, the present application provides a battery cell, which includes a shell, a pressure relief mechanism and an electrode assembly. The shell has a first end wall and a side wall, and the side wall is arranged around the first end wall. The first end wall includes a main body and a protrusion, and the protrusion protrudes from the inner surface of the main body. The pressure relief mechanism is arranged in the main body. The electrode assembly is accommodated in the shell. The electrode assembly includes a main body and a first pole ear, and the first pole ear is arranged at one end of the main body. A first gap is formed between the outer peripheral surface of the main body and the inner surface of the side wall. The first current collector is located between the first end wall and the electrode assembly. The protrusion is connected to the first current collector. In the thickness direction of the first end wall, a second gap is formed between the main body and the first current collector. The first gap and the second gap are connected.

[0009] In the technical solution of the embodiment of the present application, a protrusion is provided on the first end wall so that a second gap connected to the first gap is formed between the main body of the first end wall and the first current collector. The pressure relief mechanism is provided on the main body so that the pressure relief mechanism can remain unobstructed with the first gap. Therefore, when the battery cell thermally runs away, the gas inside the battery cell can reach the pressure relief mechanism in time and be discharged from the pressure relief mechanism, thereby improving the reliability of the battery cell.

[0010] In one or more embodiments of the first aspect, a recessed portion is formed on the outer surface of the first end wall at a position corresponding to the raised portion.

[0011] In the above solution, providing a recess corresponding to the protrusion substantially does not increase the overall weight of the first end wall, thereby facilitating a higher mass energy density for the battery cell. When the protrusion is welded to the first current collector, the provision of the recess prevents the weld mark from extending beyond the outer surface of the first end wall, thereby reducing the height dimension of the battery cell in the thickness direction of the first end wall and improving the energy density of the battery cell.

[0012] In one or more embodiments of the first aspect, along the thickness direction of the first end wall, a projection of the pressure relief mechanism does not overlap with a projection of the protrusion.

[0013] In the above solution, since the projection of the pressure relief mechanism does not overlap with the projection of the convex portion, the pressure relief mechanism will not be blocked by the convex portion, thereby improving the smoothness of the exhaust.

[0014] In one or more embodiments of the first aspect, a plurality of protrusions are provided, and the plurality of protrusions are distributed at intervals along the circumference of the first end wall.

[0015] In the above solution, by providing a plurality of convex portions spaced apart along the circumferential direction of the first end wall, the connection stability between the first end wall and the first current collector can be improved.

[0016] In one or more embodiments of the first aspect, a plurality of pressure relief mechanisms are provided, and a pressure relief mechanism is provided between every two adjacent protrusions.

[0017] In the above solution, multiple pressure relief mechanisms are provided, which helps to increase the pressure relief area of ​​the battery cell. After the pressure relief mechanism is opened, since the pressure relief mechanism is arranged between two adjacent protrusions, most of the open area of ​​each pressure relief mechanism will be connected to the second gap, which helps to further improve the pressure relief efficiency of the battery cell.

[0018] In one or more embodiments of the first aspect, the electrode assembly has a winding center hole, the first end wall has a central area corresponding to the winding center hole, and multiple pressure relief mechanisms are provided, and the multiple pressure relief mechanisms are spaced around the central area.

[0019] In the above scheme, multiple pressure relief mechanisms are arranged at intervals around the central area, which means that the pressure relief mechanisms are close to the area where gas production of the electrode assembly is concentrated, so that when the battery cell thermal runaway occurs, the gas can reach the pressure relief mechanism in time and be discharged from the pressure relief mechanism, thereby improving the reliability of the battery cell.

[0020] In one or more embodiments of the first aspect, the plurality of pressure relief mechanisms are distributed in an annular array around the center of the first end wall.

[0021] In the above solution, multiple pressure relief mechanisms are distributed in a circular array around the center of the first end wall, which means that the difficulty of opening the multiple pressure relief mechanisms is basically the same, which is conducive to timely opening of the multiple pressure relief mechanisms and further improving the pressure relief efficiency of the battery cell.

[0022] In one or more embodiments of the first aspect, a width of the protrusion in the circumferential direction of the first end wall gradually increases in a direction away from the center of the first end wall.

[0023] In the above solution, the width of the protrusion in the circumferential direction of the first end wall gradually increases, which can make the battery cell have higher structural stability.

[0024] In one or more embodiments of the first aspect, the first current collector is provided with a first through hole penetrating along a thickness direction thereof, and the first through hole is communicated with the second gap.

[0025] In the above solution, the first current collector is provided with a first through-hole connected to the second gap. On the one hand, in the event of thermal runaway of the battery cell, some emissions can flow directly through the first through-hole into the second gap, and then more quickly flow to the pressure relief mechanism, thereby improving the pressure relief efficiency of the battery cell. On the other hand, the provision of the first through-hole also helps improve the wettability of the electrode assembly.

[0026] In one or more embodiments of the first aspect, the electrode assembly has a winding center hole, a second through hole is provided at a position of the first current collector corresponding to the winding center hole, a plurality of first through holes are provided, and the plurality of first through holes are spaced around the second through hole.

[0027] In the above solution, a plurality of first through holes are provided, which can further improve the pressure relief efficiency of the battery cell when the battery cell experiences thermal runaway, and can further improve the wettability of the electrode assembly.

[0028] In one or more embodiments of the first aspect, the battery cell further includes a second current collector. The second current collector is positioned between the first current collector and the electrode assembly. The first current collector is connected to the first end wall. The second current collector is connected to the first electrode tab. The first current collector and the second current collector are connected. The first current collector is made of the same material as the first end wall, and the second current collector is made of the same material as the first electrode tab.

[0029] In the above solution, after the first current collector and the first end wall, made of the same material, are connected, the probability of defects at the connection is low, and the battery cell's sealing is improved. After the second current collector and the first tab, made of the same material, are connected, the probability of defects at the connection is low, and the flow of current is more stable.

[0030] In one or more embodiments of the first aspect, the first current collector is connected to the first end wall to form a first connecting portion. The second current collector is connected to the first tab to form a second connecting portion. The first current collector and the second current collector are connected to form a third connecting portion. Along the thickness direction of the first end wall, the projections of the first connecting portion, the second connecting portion, and the third connecting portion do not overlap.

[0031] In the above solution, since the projections of the first connection portion, the second connection portion, and the third connection portion do not overlap, when forming different connection portions, the possibility of mutual influence between different connection portions in the battery cell is low, and the reliability of the battery cell is high.

[0032] In one or more embodiments of the first aspect, the first current collector is provided with a first through hole extending through its thickness direction, and the second current collector is provided with a third through hole extending through its thickness direction, and both the first through hole and the third through hole are connected to the second gap.

[0033] In the above scheme, the first current collector is provided with a first through hole connected to the second gap, and the second current collector is provided with a third through hole connected to the second gap. On the one hand, when the battery cell is thermally runaway, part of the emissions can directly pass through the third through hole and the first through hole and flow into the second gap, and then flow to the pressure relief mechanism faster, which can improve the pressure relief efficiency of the battery cell; on the other hand, the setting of the third through hole is also conducive to improving the wetting performance of the electrode assembly.

[0034] In one or more embodiments of the first aspect, the electrode assembly has a winding center hole. A second through hole is provided at a position corresponding to the winding center hole in the first current collector. A fourth through hole is provided at a position corresponding to the winding center hole in the second current collector. A plurality of first through holes are provided. The plurality of first through holes are spaced around the second through hole. A plurality of third through holes are provided. The plurality of third through holes are spaced around the fourth through hole.

[0035] In the above solution, multiple third through holes are provided. On the one hand, the pressure relief efficiency of the battery cell can be further improved when the battery cell is in thermal runaway; on the other hand, multiple third through holes can be provided to further improve the wettability of the electrode assembly.

[0036] In one or more embodiments of the first aspect, the housing includes an end cap and a shell, the shell having an opening, and the end cap sealing the opening. The shell includes a bottom wall and side walls, the side walls surrounding the bottom wall, and connecting the bottom wall and the end cap. The end cap is a first end wall.

[0037] In the above solution, the end cover is set as the first end wall, which can reduce the difficulty of processing the protrusion.

[0038] In one or more embodiments of the first aspect, along the radial direction of the first end wall, the protrusion abuts against the inner surface of the side wall.

[0039] In the above solution, since the protrusion abuts against the inner surface of the side wall, during the assembly of the battery cell, the protrusion can facilitate the positioning of the end cover in the radial direction, thereby reducing the assembly difficulty and improving the assembly efficiency.

[0040] In one or more embodiments of the first aspect, the protrusion has a first side surface abutting against the inner surface of the side wall and a second side surface facing the first current collector, and the first side surface and the second side surface have a rounded transition.

[0041] In the above scheme, the first side and the second side are transitioned through rounded corners, which, on the one hand, can make it easier for the protrusion to enter the shell, reducing the difficulty of assembling the end cover and the shell; on the other hand, it can reduce the risk of the protrusion scratching the inner surface of the shell during the assembly of the end cover, thereby reducing the possibility of sealing failure between the end cover and the shell.

[0042] In one or more embodiments of the first aspect, the electrode assembly further includes a second electrode tab. The first electrode tab and the second electrode tab are disposed at opposite ends of the battery cell. The battery cell further includes a third current collector and an electrode terminal. The electrode terminal is disposed on the bottom wall. The third current collector is located between the electrode assembly and the bottom wall. The third current collector connects the second electrode tab and the electrode terminal.

[0043] In the above scheme, on the one hand, the second pole tab and the electrode terminal are connected through the third current collector, which can reduce the difficulty of electrical connection between the second pole tab and the electrode terminal, so that the battery cell has a more stable current capacity; on the other hand, the electrode terminal and the end cover are respectively arranged at the opposite ends of the main body, which can reduce the risk of the setting position of the pressure relief mechanism and the electrode terminal being mutually restricted, and is conducive to the arrangement of larger or more pressure relief mechanisms to improve the pressure relief efficiency.

[0044] In one or more embodiments of the first aspect, the electrode assembly has a winding center hole, and the electrode terminal is provided with a liquid injection hole, and the liquid injection hole corresponds to the position of the winding center hole.

[0045] In the above solution, the injection hole corresponds to the winding center hole. This not only facilitates the positioning of the injection equipment and improves injection efficiency, but also improves the uniformity of the injection process, reducing the risk of electrolyte injected into the battery cell impacting the electrode assembly and damaging it. This also facilitates the full infiltration of the electrode assembly.

[0046] In a second aspect, the present application provides a battery comprising the battery cell in the above embodiment.

[0047] In the above solution, since the battery cells in one or more of the above embodiments have high reliability, the battery including the battery cells in one or more of the above embodiments also has high reliability.

[0048] In a third aspect, the present application provides an electrical device, which includes the battery cell in the above embodiment, and the battery cell is used to provide electrical energy; or, the electrical device includes the battery in the above embodiment, and the battery is used to provide electrical energy.

[0049] In the above solutions, in some embodiments, because the battery cells in one or more of the above embodiments have high reliability, the electrical equipment including the battery cells in one or more of the above embodiments also has high reliability; in other embodiments, because the batteries in one or more of the above embodiments have high reliability, the electrical equipment including the batteries in one or more of the above embodiments also has high reliability;

[0050] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, which can be implemented in accordance with the contents of the specification, and to make other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Various other advantages and benefits will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiment below. The accompanying drawings are for illustration purposes only and are not to be considered as limiting the present application. The same reference numerals are used throughout the drawings to represent the same components. In the drawings:

[0052] FIG1 is a schematic structural diagram of a vehicle according to some embodiments of the present application;

[0053] FIG2 is an exploded view of a battery according to some embodiments of the present application;

[0054] FIG3 is an exploded view of a battery cell according to some embodiments of the present application;

[0055] FIG4 is a cross-sectional view of a portion of a battery cell according to some embodiments of the present application;

[0056] FIG5 is an exploded view of a battery cell according to some other embodiments of the present application;

[0057] FIG6 is a cross-sectional view of a portion of a battery cell according to some other embodiments of the present application;

[0058] FIG7 is a partial enlarged view of point A in FIG6;

[0059] FIG8 is a partial enlarged view of point B in FIG6;

[0060] FIG9 is an axonometric view of a first end wall according to some embodiments of the present application;

[0061] FIG10 is a top view of a first end wall according to some other embodiments of the present application;

[0062] FIG11 is a cross-sectional view of a battery cell according to some other embodiments of the present application.

[0063] The accompanying drawings in the specific implementation manner are as follows:

[0064] 1000 - vehicle; 200 - controller; 300 - motor; 100 - battery; 11 - housing; 111 - first portion; 112 - second portion; 12 - battery cell; 121 - housing; 1211 - first end wall; 12110 - center area; 12111 - body; 12112 - convex portion; 12112a - first side surface; 12112b - second side surface; 12113 - concave portion; 1200 - electrode terminal; 1201 - end cap; 1202 - housing; 12021 - bottom wall; 12001 - injection hole; 12002-third current collector; 1212-side wall; 122-electrode assembly; 1221-main body; 1222-first electrode tab; 1223-winding center hole; 1224-second electrode tab; 123-pressure relief mechanism; 124-first gap; 125-first current collector; 1251-first through hole; 1252-second through hole; 126-second gap; 127-second current collector; 1271-third through hole; 1272-fourth through hole; 128-first connecting portion; 129-second connecting portion; 1210-third connecting portion. DETAILED DESCRIPTION

[0065] The following embodiments of the technical solution of the present application will be described in detail with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present application and are therefore only examples and are not intended to limit the scope of protection of the present application.

[0066] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned figure descriptions are intended to cover non-exclusive inclusions.

[0067] In the description of the embodiments of this application, the technical terms "first" and "second" are used only to distinguish different objects and should not be understood to indicate or imply relative importance or implicitly specify the quantity, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, the meaning of "plurality" is more than two, unless otherwise clearly and specifically defined.

[0068] References herein to "embodiments" mean that a particular feature, structure, or characteristic described in connection with the embodiments may be included in at least one embodiment of the present 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 herein may be combined with other embodiments.

[0069] In the description of the embodiments of the present application, the term "multiple" refers to more than two (including two). Similarly, "multiple groups" refers to more than two groups (including two groups), and "multiple pieces" refers to more than two pieces (including two pieces).

[0070] In the description of the embodiments of the present application, the technical terms "center", "height", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "top", "bottom", "inside", "outside", "axial", "radial", "circumferential", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the embodiments of the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they should not be understood as limitations on the embodiments of the present application.

[0071] 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. The shape of a battery cell may include, but is not limited to, a cylinder, a flat body, a rectangular parallelepiped, or other shapes. Battery cells, depending on the packaging method, may include, but are not limited to, cylindrical battery cells, prismatic battery cells, soft-pack battery cells, and blade battery cells.

[0072] In some high-power applications such as electric vehicles, the application of batteries includes three levels: battery cells, battery modules and batteries. The battery module is formed by electrically connecting a certain number of battery cells together and placing them in a frame in order to protect the battery cells from external impact, heat, vibration, etc. The battery refers to the final state of the battery system installed in the electric vehicle. The battery mentioned in the embodiments of the present application refers to a single physical module that includes one or more battery cells to provide higher voltage and capacity. The battery generally includes a box for encapsulating one or more battery cells. The box can reduce the risk of liquid or other foreign matter affecting the charging or discharging of the battery cells.

[0073] The following will mainly focus on cylindrical battery cells. It should be understood that the embodiments described below are also applicable to rectangular battery cells, soft-pack battery cells, or blade battery cells in some aspects.

[0074] In a typical battery cell structure, the battery cell includes a housing, an electrode assembly, and an electrolyte. The housing includes an end cap and a shell, wherein the end cap closes an opening of the shell to define a receiving space for receiving the electrode assembly.

[0075] The electrode assembly is housed in the housing. It includes a positive electrode sheet, a negative electrode sheet, and a separator. Battery cells primarily operate by the movement of metal ions between the positive and negative electrode sheets. The positive electrode sheet includes a positive current collector and a positive active material layer. The positive active material layer is coated on the surface of the positive electrode collector. The uncoated positive electrode collector protrudes from the coated positive electrode collector, serving as the positive electrode tab. For lithium-ion batteries, for example, the positive electrode collector can be made of aluminum, and the positive electrode active material can be lithium cobalt oxide, lithium iron phosphate, ternary lithium, or lithium manganese oxide. The negative electrode sheet includes a negative current collector and a negative active material layer. The negative active material layer is coated on the surface of the negative electrode collector. The uncoated negative electrode collector protrudes from the coated negative electrode collector, serving as the negative electrode tab. The negative electrode collector can be made of copper, and the negative electrode active material can be carbon, silicon, or other materials. To ensure high current flow without melting, multiple positive electrode tabs are stacked together, and multiple negative electrode tabs are stacked together. Furthermore, electrode assemblies can be formed using methods including, but not limited to, wound or laminated electrode assemblies. The following discussion will primarily focus on wound electrode assemblies, but it should be understood that the embodiments described below are also applicable to laminated electrode assemblies in some respects.

[0076] The tab generally draws electrical energy from the electrode assembly by being electrically connected to a conductive member. In some cases, the conductive member is a current collector connecting the tab and the electrode terminal. In other cases, the conductive member is the electrode terminal.

[0077] Electrode terminals generally include positive and negative electrode terminals. For cylindrical battery cells, electrode terminals are typically located in the end caps. In some other cases, electrode terminals may also be located in the housing. Multiple battery cells can be connected in series and / or in parallel via the electrode terminals for various applications.

[0078] For battery cells, there are generally at least three layers of protection measures, specifically including at least switching elements, appropriate isolation membrane materials, and pressure relief mechanisms.

[0079] A pressure relief mechanism refers to an element or component that is activated to release the internal pressure or temperature when the internal pressure or temperature or other conditions of a battery cell reaches a predetermined threshold. The threshold design varies according to different design requirements. The threshold may depend on the material of one or more of the positive electrode plate, negative electrode plate, electrolyte and separator in the battery cell. The pressure relief mechanism can take the form of an explosion-proof valve, an air valve, a pressure relief valve or a safety valve, and can specifically adopt a pressure-sensitive or temperature-sensitive element or structure, that is, when the internal pressure or temperature or other conditions of the battery cell reaches a predetermined threshold, the pressure relief mechanism executes an action or the weak structure provided in the pressure relief mechanism is destroyed, thereby forming an opening or channel for the internal pressure or temperature to be released. Generally, the melting point and / or thickness of the weak structure is lower than that of other areas of the pressure relief mechanism. For example, the weak structure can be a notched groove provided on the surface of the pressure relief mechanism.

[0080] The action of activating the pressure relief mechanism may include, but is not limited to, rupturing, breaking, tearing, or opening at least a portion of the pressure relief mechanism. Activating the pressure relief mechanism is also referred to as actuating the pressure relief mechanism. When the pressure relief mechanism is actuated, high-temperature, high-pressure substances within the battery cell are discharged from the actuated portion as exhaust. This allows pressure and temperature relief to occur within the battery cell under controlled pressure or temperature, thereby reducing the likelihood of potentially more serious accidents.

[0081] The emissions from battery cells mentioned in this application include but are not limited to: electrolyte, dissolved or split positive and negative electrode plates, fragments of separators, high-temperature and high-pressure gases generated by the reaction, flames, etc.

[0082] The pressure relief mechanism is typically located on the end cap. In the event of thermal runaway of a battery cell, high-temperature, high-pressure emissions are discharged in the direction of the pressure relief mechanism, and more specifically, toward the area where the pressure relief mechanism is activated. These emissions can be extremely powerful and destructive, potentially even enough to breach one or more structures in that direction. In embodiments where the weak structure is a scored groove, the scored groove will rupture during thermal runaway, forming an opening through which the emissions can pass.

[0083] The development of battery technology must take into account multiple design factors at the same time, such as battery energy density, cycle life, discharge capacity, charge and discharge rate and other performance parameters. In addition, the reliability of battery cells must also be considered.

[0084] In a battery cell, to extract electrical energy from the electrode assembly, the end cap is welded to the tab circumference. After the end cap is welded to the tab circumference, the housing space is divided into multiple independent subspaces, and the pressure relief mechanism located on the shell wall can only correspond to one of these subspaces. In the event of thermal runaway, even if the internal pressure, temperature, or other conditions of the battery cell have reached a predetermined threshold, the discharge from some of these subspaces cannot flow to the vicinity of the pressure relief mechanism in a timely manner, potentially preventing the pressure relief mechanism from opening in time and deteriorating the reliability of the battery cell.

[0085] In view of this, the present application provides a battery cell, which includes a shell, a pressure relief mechanism and an electrode assembly. The shell has a first end wall and a side wall, and the side wall is arranged around the first end wall. The first end wall includes a main body and a protrusion, and the protrusion protrudes from the inner surface of the main body. The pressure relief mechanism is arranged in the main body. The electrode assembly is accommodated in the shell. The electrode assembly includes a main body and a first electrode tab, and the first electrode tab is arranged at one end of the main body. A first gap is formed between the outer peripheral surface of the main body and the inner surface of the side wall. The first current collector is located between the first end wall and the electrode assembly. The protrusion is connected to the first current collector. In the thickness direction of the first end wall, a second gap is formed between the main body and the first current collector. The first gap and the second gap are connected. By arranging the pressure relief mechanism in the main body, the pressure relief mechanism can maintain unobstructed communication with the first gap, so that when the battery cell thermal runaway occurs, the gas inside the battery cell can reach the pressure relief mechanism and be discharged from the pressure relief mechanism in a timely manner, thereby improving the reliability of the battery cell.

[0086] The technical solutions described in the embodiments of the present application are applicable to battery cells, batteries, and electrical equipment using batteries.

[0087] Electrical equipment includes, but is not limited to, battery vehicles, electric vehicles, ships, and spacecraft, etc. For example, spacecraft include airplanes, rockets, space shuttles, and spacecraft, etc.

[0088] For the convenience of description, the following embodiments are described by taking a vehicle as an example of an electrical device in an embodiment of the present application.

[0089] For example, FIG1 is a schematic diagram of the structure of a vehicle 1000 according to 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. A motor 300, a controller 200, and a battery 100 may be provided inside the vehicle 1000. The controller 200 is used to control the battery 100 to power the motor 300. For example, the battery 100 may be provided at the bottom, front, or rear of the vehicle 1000. The battery 100 may be used to power the vehicle 1000. For example, the battery 100 may serve as the operating power source of the vehicle 1000 and may be used for the circuit system of the vehicle 1000, such as for the starting, navigation, and operation power requirements of the vehicle 1000. In another embodiment of the present application, the battery 100 may serve not only as the operating power source of the vehicle 1000, but also as the driving power source of the vehicle 1000, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000.

[0090] To meet different power requirements, the battery 100 may include multiple battery cells 12, wherein the multiple battery cells 12 can be connected in series, in parallel, or in a hybrid connection. Hybrid connection refers to a mixture of series and parallel connections. The battery 100 may also be referred to as a battery pack. Optionally, multiple battery cells 12 may first be connected in series, in parallel, or in a hybrid connection to form a battery module, and multiple battery modules may then be connected in series, in parallel, or in a hybrid connection to form the battery 100. In other words, multiple battery cells 12 may directly form the battery 100, or they may first form battery modules, which may then form the battery 100.

[0091] For example, referring to FIG. 2 , FIG. 2 is an exploded view of a battery 100 according to some embodiments of the present application. The battery 100 may include a plurality of battery cells 12. The battery 100 may also include a housing 11 having a hollow interior, and the plurality of battery cells 12 are housed within the housing 11. As shown in FIG. 2 , these are referred to herein as a first portion 111 and a second portion 112, respectively. The first portion 111 and the second portion 112 are fastened together. The shapes of the first portion 111 and the second portion 112 may be determined based on the combined shape of the plurality of battery cells 12. The first portion 111 and the second portion 112 may each have a single opening. For example, the first portion 111 and the second portion 112 may each be a hollow rectangular parallelepiped, each with only one open face. The opening of the first portion 111 and the opening of the second portion 112 are arranged opposite each other, and the first portion 111 and the second portion 112 are fastened together to form the housing 11 having a closed chamber. The plurality of battery cells 12 are then arranged in parallel, in series, or in a mixed configuration and then placed within the housing 11 formed by the fastening of the first portion 111 and the second portion 112.

[0092] Optionally, the battery 100 may also include other structures, which will not be described in detail here. For example, the battery 100 may also include a busbar component, which is used to achieve electrical connection between multiple battery cells 12, such as parallel connection, series connection, or mixed connection. Specifically, the busbar component can achieve electrical connection between the battery cells 12 by connecting the electrode terminals 1200 of the battery cells 12. Furthermore, the busbar component can be fixed to the electrode terminals 1200 of the battery cells 12 by welding. The electrical energy of the multiple battery cells 12 can be further led out through the box 11 through the conductive mechanism.

[0093] The number of battery cells 12 can be set to any value according to different power requirements. Multiple battery cells 12 can be connected in series, parallel, or in a hybrid manner to achieve a larger capacity or power. Since the number of battery cells 12 included in each battery 100 may be large, for ease of installation, the battery cells 12 can be grouped, and each group of battery cells 12 constitutes a battery module. The number of battery cells 12 included in a battery module is not limited and can be set according to requirements. The battery 100 may include multiple battery modules, which can be connected in series, parallel, or in a hybrid manner.

[0094] Please refer to Figure 3, which is an exploded view of a battery cell 12 in some embodiments of the present application. The battery cell 12 includes one or more electrode assemblies 122 and a shell 121. The shell 121 may include a housing 1202. The multiple walls of the housing 1202, i.e., the multiple walls of the housing 121, form a cavity, which can be used to accommodate the electrode assembly 122. The housing 1202 is determined according to the shape of the one or more electrode assemblies 122 after being combined. For example, the housing 1202 can be a hollow cylinder, and one of the surfaces of the housing 1202 has an opening so that one or more electrode assemblies 122 can be placed in the housing 1202. The housing 1202 is filled with an electrolyte, such as an electrolyte solution.

[0095] The battery cell 12 may also include an electrode terminal 1200, which is disposed on the end cap 1201 or on the wall of the housing 1202 opposite the end cap 1201. In this battery cell 12, the housing 1202 itself may serve as the output terminal of the battery cell 12. For example, the electrode terminal 1200 is the positive electrode terminal, electrically connected to the positive tab, while the housing 1202 is the negative electrode of the battery cell 12, electrically connected to the negative tab. In other embodiments, the battery cell 12 may include two electrode terminals 1200: one electrode terminal 1200 may be disposed on the end cap 1201, and the other electrode terminal 1200 may be disposed on the wall of the housing 1202 opposite the end cap 1201. The two electrode terminals 1200 serve as the positive electrode terminal and the negative electrode terminal, respectively. In this battery cell 12, the electrode assembly 122 may be provided as a single electrode assembly or as multiple electrodes, depending on actual usage requirements. Multiple independent electrode assemblies 122 may be provided within the battery cell 12.

[0096] According to some embodiments of the present application, referring to FIG3 and FIG4 , the present application provides a battery cell 12, comprising a housing 121, a pressure relief mechanism 123, and an electrode assembly 122. The housing 121 has a first end wall 1211 and a side wall 1212. The side wall 1212 is disposed around the first end wall 1211. The first end wall 1211 comprises a main body 12111 and a protrusion 12112, the protrusion 12112 protruding from the inner surface of the main body 12111. The pressure relief mechanism 123 is disposed on the main body 12111. The electrode assembly 122 is housed within the housing 121. The electrode assembly 122 comprises a main body 1221 and a first tab 1222. The first tab 1222 is disposed at one end of the main body 1221. A first gap 124 is formed between the outer circumferential surface of the main body 1221 and the inner surface of the side wall 1212. The first current collector 125 is located between the first end wall 1211 and the electrode assembly 122. The protrusion 12112 is connected to the first current collector 125. In the thickness direction of the first end wall 1211, a second gap 126 is formed between the body 12111 and the first current collector 125. The first gap 124 and the second gap 126 are in communication.

[0097] The housing 121 may include multiple walls that together define a receiving space in which the electrode assembly 122 is received. Hereinafter, "inside" refers to the side facing the receiving space, and "outside" refers to the side facing away from the receiving space.

[0098] The housing 121 itself can serve as the output terminal of the battery cell 12. For example, in some embodiments, the housing 121 can serve as the negative electrode of the battery cell 12. The material of the housing 121 can include but is not limited to metal. In embodiments where the housing 121 is metal, the material of the housing 121 can be low-carbon steel.

[0099] During use of the battery cell 12, the electrode assembly 122 will expand and deform. Gas will also be generated within the battery cell 12. To allow for expansion and temporary storage of gas, a gap, i.e., a first gap 124, is provided between the outer circumference of the electrode assembly 122 and the sidewall 1212 of the housing 121. In some embodiments, the electrode assembly 122 is a wound electrode assembly, and the outer surface of the electrode assembly 122 surrounding the winding axis is the outer circumference.

[0100] When the pressure relief mechanism 123 is turned on, it means that the pressure inside the battery cell 12 reaches a preset pressure or temperature or other predetermined threshold value and the internal pressure or temperature needs to be released. The shape of the pressure relief mechanism 123 may include but is not limited to a circle, an ellipse, a polygon, a waist shape, etc. The shape of the pressure relief mechanism 123 may be a shape with a certain degree of symmetry or an asymmetric shape. The pressure relief mechanism 123 may be a pressure relief notch, and the pressure relief notch may refer to a portion of the pressure relief mechanism 123 whose thickness and / or melting point is lower than the thickness of other areas of the pressure relief mechanism 123 excluding the pressure relief notch, for example, a notch groove or a pressure relief groove, that is, a groove is opened on the surface of the pressure relief mechanism 123, which is equivalent to thinning the thickness of the pressure relief mechanism 123 at the location where the pressure relief notch is set. The pressure relief notch can be formed by machining, etching, stamping, etc. The shape of the pressure relief notch may be an arc, a broken line, etc. The pressure relief notch may include multiple segments, for example, at least one arc segment and at least one straight line segment. Referring to FIG9 , the pressure relief score may include two straight segments spaced circumferentially along first end wall 1211. The widths of the two straight segments gradually increase as they move away from the center of first end wall 1211. In the radial direction of first end wall 1211, the ends of the two straight segments near the center of first end wall 1211 are connected by a circular arc segment, while the ends of the two straight segments away from the center of first end wall 1211 are connected by another circular arc segment. Referring to FIG10 , in some embodiments, the pressure relief score may be a circular score.

[0101] The number of the pressure relief mechanism 123 can be multiple or one. In some embodiments, the number of the pressure relief mechanism 123 is one, and the pressure relief mechanism 123 is located at the center of the body 12111.

[0102] The electrode assembly 122 includes a main body 1221 and a first tab 1222. The material of the first tab 1222 can be the same as or different from that of the main body 1221. The main body 1221 is the portion of the positive electrode current collector coated with the positive electrode active material layer, the separator, and the portion of the negative electrode current collector coated with the negative electrode active material layer. In some embodiments, the first tab 1222 is the portion of the positive electrode current collector not coated with the active material layer, i.e., the positive tab. In other embodiments, the first tab 1222 can also be the negative tab.

[0103] In some embodiments, the electrode assembly 122 is a wound electrode assembly. After winding, gaps exist between adjacent tabs. To reduce the risk of defects when connecting the first tab 1222 to the first current collector 125, the first tab 1222 may be treated to reduce gaps between the layers, facilitating connection between the first tab 1222 and the current collecting member. For example, the first tab 1222 may be flattened to gather and bring together the end regions of the first tab 1222 distal from the main body 1221. This flattening creates a dense end surface at the end of the first tab 1222 distal from the main body 1221, reducing gaps between the tabs and facilitating connection between the first tab 1222 and the current collecting member. Optionally, conductive material may be filled between adjacent tabs to reduce gaps between the tabs. In other words, generally, it is understood that there are no gaps between adjacent tabs of the same polarity that could allow emissions to pass through.

[0104] The first current collector 125 is located between the first end wall 1211 and the electrode assembly 122, meaning that the first current collector 125 is located inside the housing 121. Compared to a direct connection between the first end wall 1211 and the first electrode tab 1222, connecting the first end wall 1211 and the first electrode tab 1222 via the first current collector 125 inside the battery cell 12 reduces the risk of defects, such as microcracks, forming at the connection between the first electrode tab 1222 and the first end wall 1211, which could lead to sealing failure of the first end wall 1211.

[0105] The first end wall 1211 includes a main body 12111 and a protrusion 12112. The main body 12111 is the portion of the first end wall 1211 excluding the protrusion 12112. In the thickness direction of the first end wall 1211, the protrusion 12112 will extend beyond the inner surface of the main body 12111. The protrusion 12112 and the first current collector 125 can be connected by welding, conductive fasteners, or crimping. Referring to Figures 3 and 4, after the surface of the protrusion 12112 is connected to the surface of the first current collector 125, the protrusion 12112 will extend beyond the inner surface of the main body 12111 in the thickness direction of the first end wall 1211. A second gap 126 is formed between the inner surface of the main body 12111 and the first current collector 125.

[0106] The first current collector 125 and the first end wall 1211 may be made of the same material or different materials. In some embodiments, the first current collector 125 and the first end wall 1211 are made of the same material and are both steel, such as low-carbon steel.

[0107] The materials of the first current collector 125 and the first electrode tab 1222 can be the same or different.

[0108] Referring to the dotted arrows in FIG4 , the exhaust can flow from the interlayer gaps between the electrode sheets of the electrode assembly 122 to the second gap 126, from the first gap 124 to the second gap 126, or from the winding center hole 1223 to the second gap 126. This design allows the exhaust to flow freely within the housing 121, allowing the pressure relief mechanism 123 to activate promptly in the event of thermal runaway of the battery cell 12.

[0109] In the technical solution of the embodiment of the present application, a protrusion 12112 is provided on the first end wall 1211, so that a second gap 126 connected to the first gap 124 is formed between the main body 12111 of the first end wall 1211 and the first current collector 125. By providing the pressure relief mechanism 123 on the main body 12111, the pressure relief mechanism 123 can remain unobstructed with the first gap 124, so that when the battery cell 12 thermally runs away, the gas inside the battery cell 12 can reach the pressure relief mechanism 123 in time and be discharged from the pressure relief mechanism 123, thereby improving the reliability of the battery cell 12.

[0110] According to some embodiments of the present application, referring to FIG. 3 and FIG. 6 to FIG. 8 , a recess 12113 is formed on the outer surface of the first end wall 1211 at a position corresponding to the protrusion 12112 .

[0111] The recessed portion 12113 can be formed by machining, stamping, or the like. In some embodiments, the first end wall 1211 can be stamped to simultaneously form the convex portion 12112 and the concave portion 12113 corresponding to the convex portion 12112. The convex portion 12112 and the concave portion 12113 can be formed in one step by stamping, which improves processing efficiency and reduces costs.

[0112] The energy density of a battery cell 12 refers to the electrical energy released per unit volume or mass of the battery cell 12 on average. The greater the energy density of the battery cell 12, the more energy is stored per unit volume or weight. For example, under the premise that the total space occupied by the battery cell 12 remains unchanged, the larger the internal space of the battery cell 12 used to accommodate the electrode assembly 122, the greater the volume energy density of the battery cell 12. For example, under the premise that the internal space of the battery cell 12 used to accommodate the electrode assembly 122 remains unchanged, the smaller the total space occupied by the battery cell 12, the greater the volume energy density of the battery cell 12. For example, under the premise that the total mass of the battery cell 12 remains unchanged, the greater the mass of the electrode assembly 122 and the electrolyte, the greater the mass energy density of the battery cell 12. For example, under the premise that the mass of the electrode assembly 122 and the electrolyte remains unchanged, the smaller the total mass of the battery cell 12, the greater the mass energy density of the battery cell 12.

[0113] In the embodiment of the present application, the protrusion 12112 is connected to the first current collector 125. Referring to FIG3 , the connection between the protrusion 12112 (first end wall 1211) and the first current collector 125 forms a first connecting portion 128. Taking the method of forming the first connecting portion 128 by welding as an example, after the first connecting portion 128, i.e., the weld, is formed, the presence of the recess 12113 reduces the risk of the weld height exceeding the outer surface of the body 12111 (the outer surface of the first end wall 1211), thereby facilitating the battery cell 12 to have a higher volumetric energy density.

[0114] Since the recess 12113 is provided at the position where the convex portion 12112 is provided on the first end wall 1211 , the total mass of the material of the first end wall 1211 remains substantially unchanged, which is beneficial for the battery cell 12 to have a higher mass energy density.

[0115] In the above solution, the provision of recessed portion 12113 corresponding to protrusion 12112 substantially does not increase the overall weight of first end wall 1211, thereby facilitating a higher mass energy density for battery cell 12. When protrusion 12112 is welded to first current collector 125, the provision of recessed portion 12113 prevents the weld mark from extending beyond the outer surface of first end wall 1211, thereby reducing the height dimension of battery cell 12 in the thickness direction of first end wall 1211 and improving the energy density of battery cell 12.

[0116] According to some embodiments of the present application, referring to FIG. 3 and FIG. 4 , along the thickness direction of the first end wall 1211 , the projection of the pressure relief mechanism 123 does not overlap with the projection of the protrusion 12112 .

[0117] The protrusion 12112 is connected to the first current collector 125 , and along the thickness direction of the first end wall 1211 , the projection of the pressure relief mechanism 123 does not overlap with the projection of the protrusion 12112 , which means that the pressure relief mechanism 123 is not blocked by the protrusion 12112 .

[0118] In the above solution, since the projection of the pressure relief mechanism 123 does not overlap with the projection of the convex portion 12112 , the pressure relief mechanism 123 will not be blocked by the convex portion 12112 , thereby improving the smoothness of the exhaust.

[0119] According to some embodiments of the present application, referring to FIG3 and FIG4 , a plurality of protrusions 12112 are provided. The plurality of protrusions 12112 are distributed along the circumference of the first end wall 1211 at intervals.

[0120] There are multiple protrusions 12112 , which means, referring to FIG. 3 , the first end wall 1211 and the first current collector 125 will form first connecting portions 128 at multiple locations, making the connection between the first end wall 1211 and the first current collector 125 more stable.

[0121] In the above solution, by providing a plurality of convex portions 12112 spaced apart along the circumference of the first end wall 1211 , the connection stability between the first end wall 1211 and the first current collector 125 can be improved.

[0122] According to some embodiments of the present application, referring to Figures 3, 4 and 10, a plurality of pressure relief mechanisms 123 are provided, and a pressure relief mechanism 123 is provided between every two adjacent protrusions 12112.

[0123] A pressure relief mechanism 123 is provided between each two adjacent protrusions 12112. This means that, given that the multiple protrusions 12112 are spaced apart circumferentially along the first end wall 1211, the multiple pressure relief mechanisms 123 are also spaced apart circumferentially along the first end wall 1211. In the event of thermal runaway of a battery cell 12, exhaust from the battery cell 12 has multiple outlets circumferentially along the first end wall 1211, which helps improve the pressure relief efficiency of the battery cell 12.

[0124] In the above embodiment, multiple pressure relief mechanisms 123 are provided, which helps to increase the pressure relief area of ​​the battery cell 12. After the pressure relief mechanism 123 is opened, since the pressure relief mechanism 123 is provided between two adjacent protrusions 12112, most of the open area of ​​each pressure relief mechanism 123 will be connected to the second gap 126, which helps to further improve the pressure relief efficiency of the battery cell 12.

[0125] According to some embodiments of the present application, please refer to Figures 3, 5, 9 and 10, the electrode assembly 122 has a winding center hole 1223, the first end wall 1211 has a central area 12110 corresponding to the winding center hole 1223, and a plurality of pressure relief mechanisms 123 are provided, and the plurality of pressure relief mechanisms 123 are spaced apart around the central area 12110.

[0126] The central area 12110 of the first end wall 1211 corresponds to the winding center hole 1223 , and the remaining area of ​​the first end wall 1211 corresponds to the pole piece area of ​​the electrode assembly 122 , which is the area where the pole pieces are stacked.

[0127] Generally, gas generation is concentrated in the gaps between the electrode pieces of the electrode assembly 122. Because the electrode assembly 122 is a wound structure, the location of the winding center hole 1223 generates less gas than the rest of the electrode assembly 122. Similarly, in the event of thermal runaway of the battery cell 12, the presence of multiple pressure relief mechanisms 123 surrounding the central area 12110 means that the gas concentration area is closer to the pressure relief mechanisms 123, allowing the concentrated gas to be promptly discharged by the pressure relief mechanisms 123.

[0128] In the above scheme, multiple pressure relief mechanisms 123 are arranged at intervals around the central area 12110, which means that the pressure relief mechanism 123 is close to the area where gas production of the electrode assembly 122 is concentrated, so that when the battery cell 12 thermally runs away, the gas can reach the pressure relief mechanism 123 in time and be discharged from the pressure relief mechanism 123, thereby improving the reliability of the battery cell 12.

[0129] According to some embodiments of the present application, referring to FIG. 3 , FIG. 5 , FIG. 9 and FIG. 10 , a plurality of pressure relief mechanisms 123 are distributed in a circular array around the center of the first end wall 1211 .

[0130] The multiple pressure relief mechanisms 123 are distributed in a circular array around the center of the first end wall 1211 , which means that the multiple pressure relief mechanisms 123 have the same shape and are substantially the same in terms of difficulty in opening.

[0131] In the above solution, the difficulty of opening the multiple pressure relief mechanisms 123 is basically the same, which is conducive to timely opening of the multiple pressure relief mechanisms 123 and further improving the pressure relief efficiency of the battery cell 12.

[0132] According to some embodiments of the present application, referring to FIG. 3 , FIG. 5 and FIG. 9 , the width of the protrusion 12112 in the circumferential direction of the first end wall 1211 gradually increases in a direction away from the center of the first end wall 1211 .

[0133] After the protrusion 12112 is connected to the first current collector 125 , the width of the protrusion 12112 in the circumferential direction of the first end wall 1211 gradually increases in a direction away from the center of the first end wall 1211 , which can better disperse stress and make the structural stability of the battery cell 12 higher.

[0134] In the above solution, the width of the protrusion 12112 in the circumferential direction of the first end wall 1211 gradually increases, which can make the battery cell 12 have higher structural stability.

[0135] According to some embodiments of the present application, referring to FIG. 3 and FIG. 4 , the first current collector 125 is provided with a first through hole 1251 penetrating along a thickness direction thereof, and the first through hole 1251 is communicated with the second gap 126 .

[0136] The shape of the first through hole 1251 may include, but is not limited to, a circle, an ellipse, a polygon, and the like.

[0137] The first through holes 1251 can be formed by machining or other methods after the first current collector 125 is machined. Alternatively, the first through holes 1251 can be formed simultaneously with the machining of the first current collector 125. For example, the first through holes 1251 can be formed simultaneously with the machining of the first current collector 125 by casting, 3D printing, or other methods.

[0138] The first through hole 1251 is connected to the second gap 126 , which means that the first through hole 1251 is not blocked by the protrusion 12112 .

[0139] In the above solution, the first current collector 125 is provided with a first through hole 1251 that communicates with the second gap 126. On the one hand, when the battery cell 12 experiences thermal runaway, some emissions can flow directly through the first through hole 1251 into the second gap 126, and then flow more quickly to the pressure relief mechanism 123, thereby improving the pressure relief efficiency of the battery cell 12. On the other hand, the provision of the first through hole 1251 also helps improve the wettability of the electrode assembly 122.

[0140] According to some embodiments of the present application, referring to FIG3 and FIG4 , the electrode assembly 122 has a winding center hole 1223. The first current collector 125 is provided with a second through hole 1252 at a position corresponding to the winding center hole 1223. A plurality of first through holes 1251 are provided. The plurality of first through holes 1251 are spaced apart around the second through hole 1252.

[0141] On the premise that the projection of the protrusion 12112 does not overlap with the first through hole 1251 , providing a plurality of first through holes 1251 can increase the channels through which the electrolyte and gas can flow.

[0142] In the above solution, a plurality of first through holes 1251 are provided. On the one hand, the pressure relief efficiency of the battery cell 12 can be further improved when the battery cell 12 is in thermal runaway; on the other hand, the wettability of the electrode assembly 122 can be further improved.

[0143] According to some embodiments of the present application, referring to Figures 5-8, the battery cell 12 further includes a second current collector 127. The second current collector 127 is located between the first current collector 125 and the electrode assembly 122. The first current collector 125 is connected to the first end wall 1211. The second current collector 127 is connected to the first electrode tab 1222. The first current collector 125 and the second current collector 127 are connected. The material of the first current collector 125 is the same as that of the first end wall 1211, and the material of the second current collector 127 is the same as that of the first electrode tab 1222.

[0144] The materials of the first current collector 125 and the second current collector 127 may be the same or different.

[0145] The second current collector 127 is located between the first current collector 125 and the electrode assembly 122 , which means that the second current collector 127 is located inside the first end wall 1211 . Even if there is a defect at the connection position between the second current collector 127 and the first current collector 125 , it will not affect the sealing of the battery cell 12 .

[0146] In some embodiments, the second current collector 127 and the first tab 1222 are made of the same material, namely copper.

[0147] In some embodiments, the first current collector 125 and the first end wall 1211 are made of the same material, namely, low-carbon steel.

[0148] In some embodiments, the second current collector 127 is connected to the first electrode tab 1222 by welding, and the first current collector 125 is connected to the first end wall 1211 by welding. Because the material of the first current collector 125 is the same as that of the first end wall 1211, and the material of the second current collector 127 is the same as that of the first electrode tab 1222, the risk of welding defects between the first current collector 125 and the first end wall 1211 is low, and the welding quality rate is high. The risk of welding defects between the material of the second current collector 127 and the first electrode tab 1222 is low, and the welding quality rate is high.

[0149] In the above embodiment, after the first current collector 125 and the first end wall 1211, which are made of the same material, are connected, the probability of defects at the connection point between the two is low, and the sealing of the battery cell 12 is improved. After the second current collector 127 and the first tab 1222, which are made of the same material, are connected, the probability of defects at the connection point between the two is low, and the flow of current is more stable.

[0150] According to some embodiments of the present application, referring to Figures 5 to 8, first current collector 125 is connected to first end wall 1211 to form first connecting portion 128. Second current collector 127 is connected to first tab 1222 to form second connecting portion 129. First current collector 125 and second current collector 127 are connected to form third connecting portion 1210. Along the thickness direction of first end wall 1211, the projections of first connecting portion 128, second connecting portion 129, and third connecting portion 1210 do not overlap.

[0151] In some embodiments, the first connecting portion 128, the second connecting portion 129, and the third connecting portion 1210 may be welds formed by welding. In other embodiments, the first connecting portion 128, the second connecting portion 129, and the third connecting portion 1210 may be formed by applying pressure to form a physical connection between the corresponding two connecting components. The first connecting portion 128, the second connecting portion 129, and the third connecting portion 1210 are the parts that form a mechanical engagement between the corresponding two connecting components.

[0152] The projection of the first connection part 128, the projection of the second connection part 129 and the projection of the third connection part 1210 do not overlap with each other, which means that when the first connection part 128, the second connection part 129 and the third connection part 1210 are formed, the risk of mutual influence between different connection parts is low, for example, the risk of overlap of heat-affected zones between different welds is low.

[0153] In the above solution, since the projections of the first connection portion 128, the second connection portion 129, and the third connection portion 1210 do not overlap, when different connection portions are formed, the possibility of mutual influence between different connection portions in the battery cell 12 is low, and the reliability of the battery cell 12 is high.

[0154] According to some embodiments of the present application, referring to Figures 5-8 , the first current collector 125 is provided with a first through hole 1251 extending through its thickness. The second current collector 127 is provided with a third through hole 1271 extending through its thickness. Both the first through hole 1251 and the third through hole 1271 are connected to the second gap 126 .

[0155] The shape of the third through hole 1271 may include, but is not limited to, a circle, an ellipse, a polygon, and the like.

[0156] The third through holes 1271 can be formed by machining or other methods after first machining the second current collector 127. Alternatively, the third through holes 1271 can be formed simultaneously with the machining of the second current collector 127. For example, the third through holes 1271 can be formed simultaneously with the machining of the second current collector 127 by casting, 3D printing, or other methods.

[0157] The first through hole 1251 and the third through hole 1271 are both connected to the second gap 126 , which means that the first through hole 1251 and the third through hole 1271 are not blocked by the protrusion 12112 .

[0158] In the above scheme, the first current collector 125 is provided with a first through hole 1251 connected to the second gap 126, and the second current collector 127 is provided with a third through hole 1271 connected to the second gap 126. On the one hand, when the battery cell 12 thermally runs away, part of the emissions can directly pass through the third through hole 1271 and the first through hole 1251 and flow into the second gap 126, and then flow to the pressure relief mechanism 123 faster, which can improve the pressure relief efficiency of the battery cell 12; on the other hand, the setting of the third through hole 1271 is also conducive to improving the wetting performance of the electrode assembly 122.

[0159] According to some embodiments of the present application, referring to Figures 5-8 , the electrode assembly 122 has a winding center hole 1223. The first current collector 125 has a second through hole 1252 disposed at a position corresponding to the winding center hole 1223. The second current collector 127 has a fourth through hole 1272 disposed at a position corresponding to the winding center hole 1223. A plurality of first through holes 1251 are provided. The plurality of first through holes 1251 are spaced apart around the second through hole 1252. A plurality of third through holes 1271 are provided. The plurality of third through holes 1271 are spaced apart around the fourth through hole 1272.

[0160] On the premise that the projection of the protrusion 12112 does not overlap with the first through hole 1251 and the third through hole 1271 , providing a plurality of third through holes 1271 can increase the channels through which the electrolyte and gas can flow.

[0161] In the above solution, multiple third through holes 1271 are provided. On the one hand, the pressure relief efficiency of the battery cell 12 can be further improved when the battery cell 12 is in thermal runaway; on the other hand, multiple third through holes 1271 can be provided to further improve the wettability of the electrode assembly 122 .

[0162] According to some embodiments of the present application, referring to Figures 5-8 , housing 121 includes an end cap 1201 and a shell 1202. Shell 1202 has an opening, and end cap 1201 closes the opening. Shell 1202 includes a bottom wall 12021 and side walls 1212. Side walls 1212 are disposed around bottom wall 12021 and connect bottom wall 12021 and end cap 1201. End cap 1201 serves as a first end wall 1211.

[0163] The bottom wall 12021 and the side wall 1212 can be integrally formed or separately formed.

[0164] Since the end cover 1201 and the shell 1202 are generally processed separately, the end cover 1201 is generally a plate, and the positioning tooling required for processing the protrusion 12112 on the end cover 1201 is relatively simple, and the processing difficulty is relatively low.

[0165] In the above solution, the end cover 1201 is set as the first end wall 1211 , which can reduce the difficulty of processing the protrusion 12112 .

[0166] According to some embodiments of the present application, referring to FIG. 5 to FIG. 8 , along the radial direction of the first end wall 1211 , the protrusion 12112 abuts against the inner surface of the side wall 1212 .

[0167] 8 and 9 , along the radial direction of the first end wall 1211 , the protrusion 12112 abuts against the inner surface of the side surface, which means that the first end wall 1211 can be positioned in its radial direction by the protrusion 12112 .

[0168] In the above solution, since the protrusion 12112 abuts against the inner surface of the side wall 1212 , during the assembly of the battery cell 12 , the protrusion 12112 can facilitate the radial positioning of the end cover 1201 , thereby reducing assembly difficulty and improving assembly efficiency.

[0169] According to some embodiments of the present application, referring to Figures 5 to 8, the protrusion 12112 has a first side surface 12112a abutting the inner surface of the side wall 1212 and a second side surface 12112b facing the first current collector 125, and the first side surface 12112a and the second side surface 12112b have a rounded transition.

[0170] 8 , the first side surface 12112 a is the circumferential surface of the end cover 1201 , and the second side surface 12112 b is the upper surface of the end cover 1201 .

[0171] In the above scheme, the first side surface 12112a where the protrusion 12112 abuts against the inner surface of the side wall 1212 is set as a chamfered surface. On the one hand, it can make it easier for the protrusion 12112 to enter the shell 1202, reducing the difficulty of assembling the end cover 1201 and the shell 1202; on the other hand, it can reduce the risk of the protrusion 12112 scratching the inner surface of the shell 1202 during the assembly of the end cover 1201, thereby reducing the possibility of sealing failure between the end cover 1201 and the shell 1202.

[0172] According to some embodiments of the present application, referring to Figures 5 to 8 , the electrode assembly 122 further includes a second electrode tab 1224. The first electrode tab 1222 and the second electrode tab 1224 are respectively disposed at opposite ends of the body 1221. The battery cell 12 further includes a third current collector 12002 and an electrode terminal 1200. The electrode terminal 1200 is disposed on the bottom wall 12021. The third current collector 12002 is located between the electrode assembly 122 and the bottom wall 12021. The third current collector 12002 connects the second electrode tab 1224 and the electrode terminal 1200.

[0173] The third current collector 12002 is located between the electrode assembly 122 and the bottom wall 12021 , which means that the third current collector 12002 is located inside the bottom wall 12021 .

[0174] In some embodiments, the second tab 1224 is made of aluminum.

[0175] In some embodiments, electrode terminal 1200 is a positive electrode terminal.

[0176] Connecting the second electrode tab 1224 and the electrode terminal 1200 through the third current collector 12002 allows the electrode terminal 1200 to fit tightly with the third current collector 12002 , reducing the risk of defects when connecting the electrode terminal 1200 and the second electrode tab 1224 .

[0177] The pressure relief mechanism 123 is disposed on the first end wall 1211 , and the electrode terminal 1200 is disposed on the bottom wall 12021 , which means that the position of the pressure relief mechanism 123 does not conflict with the position of the electrode terminal 1200 .

[0178] In the above scheme, on the one hand, the second pole tab 1224 and the electrode terminal 1200 are connected through the third current collector 12002, which can reduce the difficulty of electrical connection between the second pole tab 1224 and the electrode terminal 1200, so that the battery cell 12 has a more stable current flow capacity; on the other hand, the electrode terminal 1200 and the end cover 1201 are respectively arranged at the opposite ends of the main body 1221, which can reduce the risk of the setting position of the pressure relief mechanism 123 and the electrode terminal 1200 being mutually restricted, which is conducive to the arrangement of larger or more pressure relief mechanisms 123 to improve the pressure relief efficiency.

[0179] According to some embodiments of the present application, referring to FIG. 11 , the electrode assembly 122 has a winding center hole 1223 , and the electrode terminal 1200 is provided with a liquid injection hole 12001 , which corresponds to the position of the winding center hole 1223 .

[0180] Electrolyte can be injected into the battery cell 12 through the injection hole 12001 .

[0181] In the above solution, the injection hole 12001 corresponds to the winding center hole 1223. This not only facilitates the positioning of the injection equipment and improves injection efficiency, but also improves the uniformity of the injection process, reducing the risk of the electrolyte injected into the battery cell 12 impacting the electrode assembly 122 and damaging the electrode assembly 122 during the injection process. This also helps ensure that the electrode assembly 122 is fully wetted.

[0182] According to some embodiments of the present application, the present application provides a battery 100 including the battery cell 12 described in any of the above solutions.

[0183] In the above solution, since the battery cells 12 in one or more of the above embodiments have high reliability, the battery 100 including the battery cells 12 in one or more of the above embodiments also has high reliability.

[0184] According to some embodiments of the present application, the present application provides an electrical device, which includes the battery cell 12 described in any of the above schemes, and the battery cell 12 is used to provide electrical energy; or, the electrical device includes the battery 100 in the above embodiments, and the battery 100 is used to provide electrical energy.

[0185] According to some embodiments of the present application, with reference to Figures 5-9 and 11, the present application provides a battery cell 12, which includes a housing 121, multiple pressure relief mechanisms 123, an electrode assembly 122, a first current collector 125, a second current collector 127, a third current collector 12002, and an electrode terminal 1200. The electrode assembly 122 is a wound electrode assembly. The housing 121 includes an end cap 1201 and a shell 1202. The shell 1202 has an opening, and the end cap 1201 closes the opening. The shell 1202 includes a bottom wall 12021 and a side wall 1212. The side wall 1212 is arranged around the bottom wall 12021 and connects the bottom wall 12021 and the end cap 1201. The end cap 1201 includes a main body 12111 and multiple protrusions 12112. The protrusions 12112 protrude from the inner surface of the main body 12111 and are spaced apart along the circumference of the end cap 1201. The width of the protrusions 12112 increases gradually as they move away from the center of the end cap 1201. A pressure relief mechanism 123 is provided on the main body 12111. A pressure relief mechanism 123 is provided between each two adjacent protrusions 12112. Along the thickness of the end cap 1201, the projection of the pressure relief mechanism 123 does not overlap with the projection of the protrusions 12112. The multiple pressure relief mechanisms 123 are arranged in a circular array centered on the first end wall 1211. The electrode assembly 122 is housed within the housing 121. The electrode assembly 122 includes a main body 1221 and a first tab 1222. The first tab 1222 is provided at one end of the main body 1221. A first gap 124 is formed between the outer circumferential surface of the main body 1221 and the inner surface of the side wall 1212. The first current collector 125 is located between the end cap 1201 and the electrode assembly 122. The plurality of protrusions 12112 are all connected to the first current collector 125. In the thickness direction of the end cap 1201, a second gap 126 is formed between the main body 12111 and the first current collector 125. The first gap 124 and the second gap 126 are connected. A recess 12113 is stamped into the outer surface of the end cap 1201 at a position corresponding to the protrusion 12112. The second current collector 127 is located between the first current collector 125 and the electrode assembly 122. The first current collector 125 is connected to the end cap 1201. The second current collector 127 is connected to the first electrode tab 1222. The first current collector 125 and the second current collector 127 are connected. The first current collector 125 is made of the same material as the end cap 1201, and the second current collector 127 is made of the same material as the first electrode tab 1222. The electrode assembly 122 has a winding center hole 1223, and the electrode terminal 1200 is provided with a liquid injection hole 12001, which corresponds to the position of the winding center hole 1223. The first current collector 125 has a first through hole 1251. The second current collector 127 has a third through hole 1271. Both the first through hole 1251 and the third through hole 1271 are connected to the second gap 126.A second through-hole 1252 is provided at a position corresponding to the winding center hole 1223 of the first current collector 125, and a fourth through-hole 1272 is provided at a position corresponding to the winding center hole 1223 of the second current collector 127. Multiple first through-holes 1251 are provided. Multiple first through-holes 1251 are spaced around the second through-hole 1252. Multiple third through-holes 1271 are provided. Multiple third through-holes 1271 are spaced around the fourth through-hole 1272. Along the radial direction of the end cap 1201, the protrusion 12112 abuts the inner surface of the sidewall 1212. The protrusion 12112 has a first side surface 12112a abutting the inner surface of the sidewall 1212, and a second side surface 12112b facing the first current collector 125. The first side surface 12112a and the second side surface 12112b have rounded corners. The electrode assembly 122 also includes a second electrode tab 1224. The first electrode tab 1222 and the second electrode tab 1224 are respectively disposed at opposite ends of the body 1221. The battery cell 12 also includes a third current collector 12002 and an electrode terminal 1200. The electrode terminal 1200 is disposed on the bottom wall 12021. The third current collector 12002 is located between the electrode assembly 122 and the bottom wall 12021. The third current collector 12002 connects the second electrode tab 1224 and the electrode terminal 1200. By providing a protrusion 12112 on the first end wall 1211, a second gap 126 communicating with the first gap 124 is formed between the body 12111 of the first end wall 1211 and the first current collector 125. By providing the pressure relief mechanism 123 on the body 12111, the pressure relief mechanism 123 maintains unobstructed contact with the first gap 124. This allows the gas within the battery cell 12 to reach and be discharged from the pressure relief mechanism 123 in a timely manner in the event of thermal runaway of the battery cell 12, thereby improving the reliability of the battery cell 12. The protrusion 12112 can not only be used to form the second gap 126 with the first current collector 125 , but also be used to position the end cap 1201 with the housing 1202 .

[0186] 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, Comprising: A housing having a first end wall and a side wall, the side wall surrounding the first end wall, the first end wall including a body and a convex portion, the convex portion protruding from the inner surface of the body; A pressure relief mechanism disposed on the body; An electrode assembly received in the housing, the electrode assembly including a main body and a first tab, the first tab being disposed at one end of the main body, a first gap being formed between the outer peripheral surface of the main body and the inner surface of the side wall; A first current collector located between the first end wall and the electrode assembly, the convex portion being connected to the first current collector, a second gap being formed between the body and the first current collector in the thickness direction of the first end wall, the first gap and the second gap being in communication.

2. The battery cell according to claim 1, wherein A concave portion is formed at a position on the outer surface of the first end wall corresponding to the convex portion.

3. The battery cell according to claim 1 or 2, characterized in that, In the thickness direction of the first end wall, the projection of the pressure relief mechanism does not overlap with the projection of the convex portion.

4. The battery cell according to any one of claims 1 to 3, characterized in that, A plurality of the convex portions are provided, and the plurality of convex portions are spaced apart from each other in the circumferential direction of the first end wall.

5. The battery cell according to claim 4, characterized in that, A plurality of the pressure relief mechanisms are provided, and the pressure relief mechanism is provided between every two adjacent convex portions.

6. The battery cell according to any one of claims 1-5, characterized in that, The electrode assembly has a winding central hole, the first end wall has a central region corresponding to the winding central hole, a plurality of the pressure relief mechanisms are provided, and the plurality of pressure relief mechanisms are spaced apart around the central region.

7. The battery cell according to claim 6, wherein The plurality of pressure relief mechanisms are distributed in an annular array centered on the center of the first end wall.

8. The battery cell according to any one of claims 1-7, characterized in that, In a direction away from the center of the first end wall, the width of the convex portion in the circumferential direction of the first end wall gradually increases.

9. The battery cell according to any one of claims 1-8, characterized in that, The first current collector is provided with a first through hole penetrating in its thickness direction, and the first through hole is in communication with the second gap.

10. The battery cell according to claim 9, wherein, The electrode assembly has a winding central hole, a second through hole is provided at a position of the first current collector corresponding to the winding central hole, a plurality of the first through holes are provided, and the plurality of first through holes are spaced apart around the second through hole.

11. The battery cell according to any one of claims 1-10, characterized in that, The battery cell further includes a second current collector, the second current collector being located between the first current collector and the electrode assembly, the first current collector being connected to the first end wall, the second current collector being connected to the first tab, and the first current collector and the second current collector being connected; The material of the first current collector is the same as that of the first end wall, and the material of the second current collector is the same as that of the first tab.

12. The battery cell according to claim 11, wherein, The first current collector and the first end wall are connected to form a first connection portion, the second current collector and the first tab are connected to form a second connection portion, the first current collector and the second current collector are connected to form a third connection portion, and in the thickness direction of the first end wall, the projections of the first connection portion, the second connection portion, and the third connection portion do not overlap each other.

13. The battery cell according to claim 12, characterized in that, The first current collector is provided with a first through hole penetrating in its thickness direction, the second current collector is provided with a third through hole penetrating in its thickness direction, and both the first through hole and the third through hole are in communication with the second gap.

14. The battery cell according to claim 13, wherein, The electrode assembly has a winding center hole, a second through hole is provided at a position corresponding to the winding center hole on the first current collector, a fourth through hole is provided at a position corresponding to the winding center hole on the second current collector, a plurality of first through holes are provided, and the plurality of first through holes are spaced around the second through hole; A plurality of third through holes are provided, and the plurality of third through holes are spaced around the fourth through hole.

15. The battery cell according to any one of claims 1-14, characterized in that, The housing includes an end cap and a housing body. The housing body has an opening, and the end cap closes the opening. The housing body includes a bottom wall and a side wall. The side wall surrounds the bottom wall, and the side wall connects the bottom wall and the end cap; Wherein, the end cap is the first end wall.

16. The battery cell according to claim 15, wherein, Along the radial direction of the first end wall, the convex portion abuts against the inner surface of the side wall.

17. The battery cell according to claim 16, wherein The convex portion has a first side surface abutting against the inner surface of the side wall and a second side surface facing the first current collector, and the first side surface and the second side surface are rounded.

18. The battery cell according to claim 16 or 17, characterized in that, The electrode assembly further includes a second tab, and the first tab and the second tab are respectively arranged at opposite ends of the main body; The battery cell further includes a third current collector and an electrode terminal. The electrode terminal is arranged on the bottom wall. The third current collector is located between the electrode assembly and the bottom wall, and the third current collector connects the second tab and the electrode terminal.

19. The battery cell according to claim 18, wherein, The electrode assembly has a winding center hole, and the electrode terminal is provided with a liquid injection hole, and the liquid injection hole corresponds to the position of the winding center hole.

20. A battery, characterized in that, Including the battery cell according to any one of claims 1-19.

21. An electrical device, characterized in that, The electrical device includes the battery cell according to any one of claims 1-19, and the battery cell is used to provide electric energy; Or, the electrical device includes the battery according to claim 20, and the battery is used to provide electric energy.

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