Battery cell, battery and electrical apparatus

Abstract

The present application relates to a battery cell, a battery and an electrical apparatus. The battery cell comprises a casing, at least one electrode component and a thermal conduction structure; the casing is provided with a heat exchange casing wall, the heat exchange casing wall being used for transferring heat inside the battery cell to a heat exchange structure outside the casing; the thermal conduction structure and all of the electrode component are accommodated inside the casing, the thermal conduction structure being arranged between the electrode component and the heat exchange casing wall for heat transfer. In the technical solution of the present application, the casing is provided with the heat exchange casing wall in contact with the heat exchange structure outside, and the thermal conduction structure is provided between the electrode component and the heat exchange casing wall, so that the heat of the electrode component can be rapidly transferred to the heat exchange casing wall via the thermal conduction structure, and then is rapidly transferred to the heat exchange structure outside via the heat exchange casing wall so as to undergo a rapid heat exchange with the heat exchange structure, thereby improving the heat exchange efficiency of the battery cell and thus improving the reliability of a battery.

Description

Battery cells, batteries and electrical devices

[0001] Cross-references

[0002] This application refers to Chinese patent application No. 202321970108.4, filed on July 25, 2023, entitled “Battery Cell, Battery and Electrical Device,” which is incorporated herein by reference in its entirety. 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] A battery cell is the smallest unit in a battery that enables charge and discharge. Electric vehicles are increasingly demanding fast-charging of battery cells. The high overcurrent rate during fast-charging means the temperature rise is far higher than that caused by heating of conventional slow-charging battery cells. High temperatures can easily cause battery cell explosions, reducing battery reliability.

[0005] Summary of the Invention

[0006] In view of the above problems, the present application provides a battery cell, a battery, and an electrical device, which can improve the heat dissipation effect of the battery cell and thus enhance the reliability of the battery.

[0007] In a first aspect, the present application provides a battery cell comprising a housing, at least one electrode assembly, and a heat-conducting structure. The housing has a heat-exchange shell wall, which is used to transfer heat from the battery cell to the heat-exchange structure located outside the housing. The heat-conducting structure and all electrode assemblies are housed within the housing, and a heat-conducting structure is provided between the electrode assembly and the heat-exchange shell wall for heat conduction.

[0008] In the technical solution of the embodiment of the present application, the shell has a heat exchange shell wall in contact with the external heat exchange structure, and a heat-conducting structure is arranged between the electrode assembly and the heat exchange shell wall. The heat of the electrode assembly can be quickly transferred to the heat exchange shell wall through the heat-conducting structure, and then quickly transferred from the heat exchange shell wall to the external heat exchange structure, and then quickly exchange heat with the heat exchange structure. When the battery cell needs to dissipate heat and cool down, its heat dissipation efficiency is high, which helps to improve the reliability of the battery.

[0009] In some embodiments, the outer surface of at least one electrode assembly is positioned facing the heat exchange shell wall, and a heat-conducting structure is disposed between at least one set of these facing outer surfaces and the heat exchange shell wall. In this case, the heat-conducting structure disposed between at least one set of these facing outer surfaces and the heat exchange shell wall allows heat to be transferred directly from these outer surfaces to the heat exchange shell wall, shortening the heat transfer path, increasing heat transfer efficiency, and improving heat exchange efficiency among the battery cells.

[0010] In some embodiments, at least one outer surface of at least one electrode assembly in the height direction is a first heat dissipation surface, and the electrode tab of the electrode assembly is located at at least one end in the height direction. The heat exchange shell wall includes a first shell wall, and the first heat dissipation surface and the first shell wall are arranged opposite to each other in the height direction, and a heat conductive structure is provided between the two. Since the tab is arranged in the height direction of the electrode assembly, the outer surface serving as the first heat dissipation surface can expose the electrode pieces / insulators in the electrode assembly (each electrode piece is separated by an isolator), so that the heat conductive structure can contact the internal electrode pieces / insulators of the electrode assembly, making it easy to extract the internal heat of the electrode assembly, and the heat exchange efficiency of the electrode assembly is high.

[0011] In some embodiments, an electrode assembly includes a positive electrode sheet and a negative electrode sheet, each of which includes a current collecting substrate. In an electrode assembly having a first heat dissipation surface, the current collecting substrate of at least one of the positive electrode sheet and the negative electrode sheet includes a protrusion protruding from the first heat dissipation surface, and a heat conductive structure located between the first heat dissipation surface and the first shell wall is thermally connected to the protrusion. Because the protrusion is formed by protruding from the current collecting substrate, the current collecting substrate generally has good thermal conductivity. Such a protrusion has good thermal conductivity, and heat from the current collecting substrate can be directly and quickly conducted away through the protrusion, thereby helping to improve the heat exchange efficiency of the electrode assembly.

[0012] In some embodiments, in an electrode assembly with a first heat dissipation surface, the tab and the first heat dissipation surface are disposed opposite each other in the height direction of the electrode assembly. This separation of the protrusion and the tab allows for the use of a conventional housing structure to a large extent, reducing the cost of battery cell improvements.

[0013] In some embodiments, the thermally conductive structure includes a thermally conductive insulating layer disposed on the inner side of the first shell wall and connected between the first shell wall and the protrusion. Because the protrusion increases the height dimension of the electrode assembly, utilizing the thermally conductive insulating layer to thermally connect between the protrusion and the first shell wall helps reduce the height dimension of the battery cell and improve the energy density of the battery cell.

[0014] In some embodiments, the thickness of the thermally conductive insulating layer is L1, and the protruding height of the protruding portion is L2, satisfying the following conditions: L1 < 3 mm, and / or L2 < 6 mm. When L1 satisfies L1 < 3 mm, or L2 satisfies L2 < 6 mm, the energy density and processing cost of the battery cell are relatively moderate, while also achieving a certain degree of heat exchange efficiency.

[0015] In some embodiments, the thermally conductive insulating layer includes at least one of a polyimide layer, an epoxy resin layer, a phenolic resin layer, a urea-formaldehyde resin layer, a polyetheretherketone layer, a polybenzimidazole layer, an aluminum oxide layer, a boehmite layer, and a silicon carbide layer. In this case, the thermally conductive insulating layer has good thermal conductivity and insulation properties.

[0016] In some embodiments, L1 satisfies: 0.02 mm ≤ L1 ≤ 0.6 mm, and / or L2 satisfies: 1 mm ≤ L2 ≤ 4 mm. In this case, the energy density of the battery cell is better and has a certain heat exchange efficiency.

[0017] In some embodiments, at least one outer surface of at least one electrode assembly in the thickness direction serves as a second heat dissipation surface. The heat exchange shell includes the second shell wall. The second heat dissipation surface and the second shell wall are arranged opposite each other in the thickness direction, with a heat conductive structure disposed therebetween. In this case, the second heat dissipation surface, which has a larger surface area in the electrode assembly, is connected to the heat conductive structure, increasing the contact area between the electrode assembly and the second heat dissipation surface and improving heat exchange efficiency.

[0018] In some embodiments, multiple electrode assemblies are arranged sequentially along their thickness, with a through-space formed between each adjacent electrode assemblies. The thermally conductive structure includes a first thermally conductive insulating pad extending into each through-space and connected to the outer surface of each through-space. In this case, the same first thermally conductive insulating pad can be thermally connected to the thick-walled outer surfaces of two electrode assemblies, resulting in a higher thermal conductivity structure for the entire electrode assembly as a whole.

[0019] In some embodiments, the first thermally conductive insulating pad extends continuously, with each of the through-spaces sequentially arranged along the thickness of the electrode assembly located sequentially along the extension path of the first thermally conductive insulating pad, and the first thermally conductive insulating pad is disposed between the second heat dissipation surface and the second shell wall. In this case, the first thermally conductive insulating pad can make thermal contact with the outer surfaces of the plurality of electrode assemblies along the thickness direction along the extension path, thereby enhancing the heat exchange efficiency between the second shell wall and the electrode assembly.

[0020] In some embodiments, the thickness of the first thermally conductive insulating pad is L3, which satisfies: L3 < 4 mm. When L3 < 4 mm, the battery cell can achieve both high energy density of the battery cell and high thermal conductivity of the first thermally conductive insulating pad.

[0021] In some embodiments, L3 satisfies: 0.3 mm ≤ L3 ≤ 2 mm. In this case, the energy density and thermal conductivity of the battery cell are both good.

[0022] In some embodiments, one of the widthwise outer surfaces of each electrode assembly serves as a third heat dissipation surface, and the third heat dissipation surfaces of adjacent electrode assemblies are disposed opposite each other in the widthwise direction. The third heat dissipation surface is in surface contact with the first thermally conductive insulating pad. In this case, not only is the contact area between the first thermally conductive insulating pad and the electrode assembly increased, but the first thermally conductive insulating pad and electrode assembly are more tightly wound, thereby enhancing the positional stability of each electrode assembly.

[0023] In some embodiments, at least one outer surface of at least one electrode assembly in the width direction serves as a third heat dissipation surface. The housing includes a third housing wall, and the third heat dissipation surface and the third housing wall are disposed opposite each other, with a heat conductive structure disposed therebetween. In this case, by disposing the heat conductive structure between the third housing wall and the third heat dissipation surface, the transmission path for heat from the electrode assembly to be transferred to the housing can be increased, thereby improving the degree of heat exchange between the housing and the exterior, thereby facilitating heat dissipation from the battery cells.

[0024] In some embodiments, a plurality of electrode assemblies are arranged along the thickness direction of the electrode assemblies, and a through-space is formed between each adjacent electrode assemblies. The heat-conducting structure includes a second heat-conducting insulating pad, a portion of which extends into each through-space and is connected to the outer surface forming each through-space, and the remaining portion of the second heat-conducting insulating pad is arranged between all third heat dissipation surfaces and the third shell. In this case, the second heat-conducting insulating pad can extend into the through-space between the electrode assemblies and heat-conductingly connect adjacent electrode assemblies, which can improve the thermal conductivity between the electrode assemblies and the shell, and help improve the heat dissipation efficiency of the battery cell from the internal heat to the outside.

[0025] In a second aspect, the present application provides a battery, comprising a heat exchange structure and the above-mentioned battery cell, wherein the heat exchange structure is located outside the shell and contacts the heat exchange shell wall.

[0026] In some embodiments, the battery includes a housing, and multiple battery cells are arranged, all of which are supported side by side on the bottom inner wall of the housing. A heat exchange structure is arranged between adjacent battery cells, and / or between the bottom inner wall and the battery cells. In this case, a battery cell heat dissipation scheme that matches different heat exchange structure arrangements can be configured to shorten the heat exchange path between the heat exchange structure and the electrode assembly through the heat exchange shell wall and heat conductive structure, thereby improving the heat exchange efficiency of the heat exchange structure to the electrode assembly.

[0027] In a third aspect, the present application provides an electrical device, which includes the battery in the above embodiment, and the battery is used to provide electrical energy.

[0028] 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, it can be implemented in accordance with the contents of the specification. In order to make the above and 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

[0029] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following briefly introduces the drawings required for use in the embodiments of the present application. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on the drawings without inventive work. In the drawings:

[0030] FIG1 is a schematic structural diagram of a vehicle according to one or more embodiments.

[0031] FIG2 is a schematic structural diagram of a battery according to one or more embodiments.

[0032] FIG3 is an exploded schematic diagram of the battery shown in FIG2 .

[0033] FIG4 is an enlarged view of point A in FIG2 .

[0034] FIG5 is an exploded schematic diagram of a battery according to one or more further embodiments.

[0035] FIG6 is a schematic diagram illustrating the external appearance of a battery cell according to one or more embodiments.

[0036] FIG. 7 is a schematic diagram of an interlayer structure of an electrode assembly according to one or more embodiments.

[0037] FIG8 is a schematic diagram of the internal structure of the battery cell in the embodiment shown in FIG2 .

[0038] FIG. 9 is an exploded view of the battery cell in the embodiment shown in FIG. 8 .

[0039] FIG10 is a cross-sectional view of a battery cell in the embodiment shown in FIG2 .

[0040] FIG11 is a schematic diagram of a partial internal structure of a battery cell in the embodiment shown in FIG5 .

[0041] FIG12 is a cross-sectional view of the battery cell shown in FIG11 .

[0042] The reference numerals in the drawings in the specific embodiment are as follows: 1000, vehicle; 100, battery; 200, controller; 300, motor; 10, housing; 10a, bottom inner wall; 20, battery cell; 21, housing; 21a, heat exchange shell wall; a1, first shell wall; a2, second shell wall; a3, third shell wall; 22, electrode assembly; 22b, outer surface; b1, first heat dissipation surface; b2, second heat dissipation surface; k, through-space; b3, third heat dissipation surface; 22c, positive electrode sheet; 22d , negative electrode sheet; J, current collecting matrix; J1, electrode ear; J11, positive electrode ear; J12, negative electrode ear; J2, protrusion; X, thickness direction; Y, width direction; Z, height direction; 22e, separator; 22f, electrode terminal; 23, thermal conductive structure; 23a, first thermal conductive insulating pad; 23b, thermal conductive insulating layer; 23c, second thermal conductive insulating pad; c1, first thermal conductive insulating part; c2, second thermal conductive insulating part; 30, heat exchange structure. DETAILED DESCRIPTION

[0043] 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.

[0044] 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.

[0045] In the description of the embodiments of this application, the use of technical terms such as "first" and "second" is solely for distinguishing different objects and should not be understood as indicating or implying relative importance or implicitly indicating the quantity, specific order, or primary and secondary relationship of the technical features indicated. In the description of the embodiments of this application, the meaning of "plurality" is more than two, unless otherwise specifically defined.

[0046] 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.

[0047] In the description of the embodiments of this application, the term "and / or" is used to describe the association relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in this document, if it appears, generally indicates that the related objects are in an "or" relationship.

[0048] In the description of the embodiments of the present application, if it appears, 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).

[0049] In the description of the embodiments of the present application, if any, technical terms such as "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", and "circumferential" 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.

[0050] In the description of the embodiments of the present application, unless otherwise expressly specified or limited, technical terms such as "installed," "connected," "connected," and "fixed" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integration; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; internal connections between two components or interactions between two components. Those skilled in the art can understand the specific meanings of the above terms in the embodiments of the present application based on specific circumstances.

[0051] Currently, market developments indicate that power batteries are becoming increasingly widely used. They are not only used in energy storage systems such as hydropower, thermal power, wind power, and solar power plants, but are also widely used in electric vehicles such as electric bicycles, electric motorcycles, and electric vehicles. As the application of power batteries continues to expand, market demand is also growing.

[0052] A battery cell (also known as a battery cell) is the smallest unit in a battery that enables charge and discharge. Electric vehicles are increasingly demanding fast-charging of battery cells. The high overcurrent rate during fast-charging of a battery cell means the temperature rise is far higher than that caused by the heating of a conventional slow-charging battery cell. High temperatures can easily cause the battery cell to explode, reducing battery reliability.

[0053] A battery cell typically consists of a casing and an electrode assembly housed within it. The electrode assembly is the primary site for electrochemical reactions in the battery cell and the primary source of heat generated within it. To cool the battery cell, a heat exchange structure is commonly installed within the battery casing to dissipate heat. This heat exchange structure contacts the battery cell casing, dissipating heat from the cell. In conventional battery cell structures, a gap often exists between the electrode assembly and the casing, leading to inefficient heat transfer between the electrode assembly and the heat exchange structure, which in turn affects the heat dissipation efficiency of the battery cell.

[0054] Based on this, in order to improve the heat dissipation efficiency of the battery cell and improve the reliability of the battery, the embodiment of the present application designs a battery cell. The main concept is that a heat-conducting structure for conducting heat is set between the shell and the electrode assembly of the battery cell, and the heat-conducting structure is in contact with the heat exchange shell wall in the shell that directly / indirectly exchanges heat with the heat exchange structure. The heat of the electrode assembly can be heat-exchanged through the heat-conducting structure, the heat exchange shell wall and the heat exchange structure. The heat transfer efficiency between the electrode assembly and the heat exchange structure is high, the heat dissipation efficiency of the battery cell is good, and it helps to improve the reliability of the battery.

[0055] The battery disclosed in the embodiments of this application includes a heat exchange structure and the battery cells mentioned in the embodiments of this application. The battery disclosed in the embodiments of this application can be used, but is not limited to, in electrical devices such as vehicles, ships, or aircraft. The battery disclosed in this application can be used to form a power supply system for such an electrical device.

[0056] The present invention provides an electrical device that uses a battery as a power source. The electrical device may be, but is not limited to, a mobile phone, a tablet, a laptop computer, an electric toy, an electric tool, an electric vehicle, an electric car, a ship, a spacecraft, etc. For ease of description, the following embodiments are described using a vehicle as an example of an electrical device according to one embodiment of the present invention.

[0057] Please refer to Figure 1, which is a schematic structural diagram of a vehicle 1000 according to one or more embodiments. The vehicle 1000 can be a fuel vehicle, a gas vehicle or a new energy vehicle. The new energy vehicle can be a pure electric vehicle, a hybrid vehicle or an extended-range vehicle, etc. A battery 100 is provided inside the vehicle 1000, and the battery 100 can be provided at the bottom, head or tail of the vehicle 1000. The battery 100 can be used to power the vehicle 1000. For example, the battery 100 can serve as an operating power source for the vehicle 1000. The vehicle 1000 may also include a controller 200 and a motor 300. The controller 200 is used to control the battery 100 to power the motor 300, for example, for starting, navigating and driving the vehicle 1000.

[0058] Please refer to Figure 2, which is a schematic diagram of the structure of a battery 100 according to one or more embodiments. The battery 100 includes a case 10 and a battery cell 20, and the battery cell 20 is accommodated in the case 10. The case 10 is used to provide a storage space for the battery cell 20, and the case 10 can adopt a variety of structures. In some embodiments, the case 10 may include a first part and a second part, the first part and the second part covering each other, and the first part and the second part jointly define a storage space for accommodating the battery cell 20. The first part can be a hollow structure with an opening at one end, and the second part can be a plate-like structure, and the second part covers the open side of the first part, so that the first part and the second part jointly define a storage space. Of course, the case 10 formed by the first part and the second part can be a variety of shapes, such as a cylinder, a cuboid, etc.

[0059] In the battery 100, there may be multiple battery cells 20, which may be connected in series, in parallel, or in a hybrid connection. A hybrid connection refers to a combination of series and parallel connections among the multiple battery cells 20. Multiple battery cells 20 may be directly connected in series, in parallel, or in a hybrid connection, and the entire battery 100 structure may then be contained within the housing 10. Alternatively, the battery 100 may be constructed by first connecting multiple battery cells 20 in series, in parallel, or in a hybrid connection to form a battery 100 module. Multiple battery modules 100 may then be connected in series, in parallel, or in a hybrid connection to form a single unit, which is then contained within the housing 10. Each battery cell 20 may be a secondary battery 100 or a primary battery 100; it may also be a lithium-sulfur battery 100, a sodium-ion battery 100, or a magnesium-ion battery 100, but is not limited thereto. The battery cells 20 may be cylindrical, flat, rectangular, or have other shapes.

[0060] The battery cell provided in the embodiments of the present application is described in detail below in conjunction with the accompanying drawings.

[0061] Figure 3 is an exploded schematic diagram of the battery shown in Figure 2. Figure 4 is an enlarged view of point A in Figure 2.

[0062] According to one or more embodiments of the present application, referring to Figures 2, 3, and 4, a battery cell 20 provided in an embodiment of the present application includes a housing 21, at least one electrode assembly 22, and a heat-conducting structure 23. The housing 21 has a heat-exchange shell wall 21a, which is used to conduct heat from the interior of the battery cell 20 to the heat-exchange structure 30 located outside the housing 21. The heat-conducting structure 23 and all electrode assemblies 22 are accommodated within the housing 21, and the heat-conducting structure 23 is provided between the electrode assembly 22 and the heat-exchange shell wall 21a for heat conduction.

[0063] The housing 21 is a component that forms an internal environment of the battery cell 20 , and the internal environment can be used to accommodate the electrode assembly 22 , the heat-conducting structure 23 , the electrolyte, etc.

[0064] Typically, the shell 21 includes a shell body (not shown) and an end cover (not shown). The shell body encloses a housing cavity for the internal environment of the battery cell 20. The housing cavity is open on one or both sides, and the end cover covers the opening of the housing cavity. The shell body and the end cover can be connected by snap-fitting, welding, etc., and the two can be arranged as one piece or separately. Typically, the shell body and the end cover are assembled and connected in the height direction Z of the battery cell 20. In conventional application scenarios, the height direction Z of the battery cell 20 is roughly the same as the direction of gravity.

[0065] Figure 5 is an exploded schematic diagram of a battery according to one or more further embodiments. Referring to Figure 5 , electrode terminals 22f are typically provided on the end caps. These terminals are used to connect the electrode assembly 22 to an external circuit. The housing 21 can be made of plastic, ceramic, metal, or other materials. To improve the thermal conductivity of the battery cells 20, the housing 21 is typically constructed of a material with high thermal conductivity, such as aluminum alloy or copper alloy.

[0066] Of course, the battery cell 20 may also include other conventional components, such as a pressure relief valve and an adapter. Typically, the pressure relief valve is located on the end cap, connecting the inside and outside of the battery cell 20 when the pressure / temperature inside the battery cell 20 exceeds a threshold. The adapter can be used to electrically connect the electrode assembly 22 and the electrode terminal 22f. In some embodiments, a plastic component may also be provided on the end cap to isolate the electrical connection components within the housing from the end cap, thereby reducing the risk of short circuits.

[0067] The heat exchange structure 30 can be a component such as a heat exchange plate or a heat exchange tube for circulating a heat exchange medium. The heat exchange medium can be a gaseous medium such as Freon, a liquid medium such as water, a refrigerant, etc. Preferably, the heat exchange structure 30 is in the shape of a plate. The plate-shaped heat exchange structure 30 can make contact with the heat exchange shell wall 21a over a large area, and the heat exchange effect is better. It should be noted that a heat exchange medium with a temperature lower than the heat exchange shell wall 21a can circulate in the heat exchange structure 30 to cool the heat exchange shell wall 21a. In some cases, a heat exchange medium with a temperature higher than the heat exchange shell wall 21a can also circulate in the heat exchange structure 30 to heat the heat exchange shell wall 21a, so that the battery cell 20 of the embodiment of the present application can have a good heat exchange with the heat exchange structure 30 whether in cooling conditions or heating conditions.

[0068] The shell 21 has a heat exchange shell wall 21a. When in use, the heat exchange shell wall 21a is used to exchange heat with the heat exchange structure 30. Specifically, the heat exchange shell wall 21a can be arranged opposite to the heat exchange structure 30, and the two can be directly connected or there can be a certain gap between them. Generally, the heat exchange shell wall 21a is in direct contact with the heat exchange structure 30, and the heat exchange efficiency is higher. The heat exchange shell wall 21a is a structure that constitutes at least a part of the shell 21, and the heat exchange shell wall 21a participates in enclosing and forming the internal environment of the battery cell 20. Taking the cylindrical battery cell 20 as an example, the heat exchange shell wall 21a can include the circumferential side wall portion of the cylindrical shell 21, and can also include the bottom wall portion of the cylindrical shell 21. Taking the square battery cell 20 as an example, the heat exchange shell wall 21a can include the front and rear side walls, left and right side walls, bottom wall and other parts of the square shell 21. It can be understood that the heat exchange shell wall 21a has a certain thickness, and the thickness is usually thin.

[0069] The electrode assembly 22 is the component where the electrochemical reaction occurs in the battery cell 20. One or more electrode assemblies 22 may be contained within the housing 21. The electrode assembly 22 is mainly formed by winding or stacking a positive electrode sheet 22c and a negative electrode sheet 22d, and a separator 22e is usually provided between the positive electrode sheet 22c and the negative electrode sheet 22d. The portions of the positive electrode sheet 22c and the negative electrode sheet 22d containing active materials constitute the main body of the electrode assembly 22, and the portions of the positive electrode sheet 22c and the negative electrode sheet 22d without active materials each constitute a tab J1. The positive tab J1 and the negative tab J1 may be located together at one end of the main body or respectively at both ends of the main body. During the charge and discharge process of the battery 100, the positive electrode active material and the negative electrode active material react with the electrolyte, and the tab J1 is connected to the electrode terminal 22f to form a current circuit.

[0070] The thermally conductive structure 23 is a component with a heat-conducting function. Its specific structural form varies, including metal, carbon fiber, and the like. Typically, to reduce the leakage of high current from the electrode assembly 22 to the housing 21, the thermally conductive structure 23 may have a certain degree of insulation. For example, the thermally conductive structure 23 may be composed of a metal body and an insulating coating applied to the surface of the metal body. Alternatively, the thermally conductive structure 23 may be formed by curing a thermally conductive insulating adhesive. Alternatively, the thermally conductive structure 23 may be a ceramic structure.

[0071] A heat-conducting structure 23 is thermally connected between the electrode assembly 22 and the heat exchange shell 21a. Typically, but not exclusively, the heat-conducting structure 23 is in direct contact with both the heat exchange shell 21a and the electrode assembly 22. The larger the contact area, the better the heat conduction efficiency. As will be appreciated, the electrode assembly 22 is electrically charged during the electrochemical reaction. In addition to providing thermal conductivity, the heat-conducting structure 23 also provides insulation, reducing the likelihood of electrical leakage from the shell 21.

[0072] Within a battery cell 20, there can be one or more electrode assemblies 22. The greater the number of electrode assemblies 22, the greater the capacity and volume of the battery cell 20. A heat-conducting structure 23 can be thermally connected between the heat exchange shell wall 21a and one or more electrode assemblies 22.

[0073] The above-mentioned battery cell 20 and the shell 21 have a heat exchange shell wall 21a in contact with the external heat exchange structure 30. A heat-conducting structure 23 is arranged between the electrode assembly 22 and the heat exchange shell wall 21a. The heat of the electrode assembly 22 can be quickly transferred to the heat exchange shell wall 21a through the heat-conducting structure 23, and then quickly transferred from the heat exchange shell wall 21a to the external heat exchange structure 30, and then quickly exchange heat with the heat exchange structure 30. When the battery cell 20 needs to dissipate heat and cool down, its heat dissipation efficiency is high, which helps to improve the reliability of the battery 100.

[0074] In some embodiments, the outer surface 22b of at least one electrode assembly 22 is arranged facing the heat exchange shell wall 21a, and a heat conductive structure 23 is provided between at least one group of outer surfaces 22b and the heat exchange shell wall 21a.

[0075] The outer surface 22b of the electrode assembly 22 is the surface outside the electrode assembly 22. When the electrode assembly 22 has a cylindrical wound structure, the outer surface 22b of the electrode assembly 22 includes the circumferential side surfaces and axial end surfaces of the cylindrical wound structure. When the electrode assembly 22 has a square wound structure or a square laminated structure, the outer surface 22b of the electrode assembly 22 includes the front and rear side surfaces, the left and right side surfaces, and the top and bottom side surfaces.

[0076] Each electrode assembly 22 typically includes multiple outer surfaces 22b. Among all electrode assemblies 22, the outer surface 22b of at least one electrode assembly 22 is arranged opposite the heat exchange shell wall 21a. The outer surface 22b and heat exchange shell wall 21a being "arranged opposite each other" means that the outer surface 22b and the heat exchange shell wall 21a are arranged opposite each other, and no other outer surface 22b exists between them. When two or more outer surfaces 22b are arranged opposite the same heat exchange shell wall 21a, a heat-conducting structure 23 may be provided between one or more of the outer surfaces 22b and the heat exchange shell wall 21a. In other words, when the outer surface 22b and the heat exchange shell wall 21a are arranged opposite each other, a heat-conducting structure 23 may not be provided between them.

[0077] When multiple electrode assemblies 22 are stacked in a group within the housing 21, and the heat exchange shell wall 21a is located on one side of the stacking direction of the electrode assemblies 22, the outer surface 22b of one side of the stacking direction of the electrode assemblies 22 in the group is disposed opposite the heat exchange shell wall 21a. When multiple electrode assemblies 22 are located in the housing 21, and the heat exchange shell wall 21a is located on one side of the electrode assemblies 22 in the height direction Z, the bottom surface of each electrode assembly 22 in the height direction Z is disposed opposite the heat exchange shell wall 21a.

[0078] The heat-conducting structure 23 may be entirely or partially located between the outer surface 22 b and the heat exchange shell wall 21 a , which are arranged opposite to each other.

[0079] At this time, a heat-conducting structure 23 is set between at least one group of outer surfaces 22b and the heat exchange shell wall 21a arranged opposite to each other. Heat can be directly transferred from these outer surfaces 22b to the heat exchange shell wall 21a, the heat transfer path is shortened, the heat transfer efficiency is faster, and the heat exchange efficiency of the battery cell 20 is higher.

[0080] FIG6 is a schematic diagram illustrating the external appearance of a battery cell 20 according to one or more embodiments.

[0081] In some embodiments, referring to Figures 4 and 6 , at least one outer surface 22b of at least one electrode assembly 22 in the height direction Z serves as a first heat dissipation surface b1, and a tab J1 of the electrode assembly 22 is located at at least one end in the height direction Z. The heat exchange shell 21a includes a first shell wall a1, and the first heat dissipation surface b1 and the first shell wall a1 are arranged opposite to each other in the height direction Z, with a heat conductive structure 23 disposed therebetween.

[0082] In the embodiment of the present application, the height direction Z of the electrode assembly 22 is the direction in which the tab J1 is located. Generally, and without limitation, the height direction Z of the electrode assembly 22 corresponds to the height direction Z of the housing 21. In conventional applications, the height direction Z of the electrode assembly 22 corresponds to the direction of gravity. Of course, the height direction Z of the electrode assembly 22 can also correspond to the width direction Y, thickness direction X, etc. of the housing 21. The height direction Z does not limit the application of the electrode assembly 22 and the battery cell 20.

[0083] The first heat dissipation surface b1 is an outer surface 22b located in the height direction Z of the electrode assembly 22 and is directly thermally connected to the opposite first shell wall a1 via the heat conducting structure 23. The first shell wall a1 is the shell wall portion of the housing 21 located in the height direction Z of the electrode assembly 22.

[0084] Typically, each electrode assembly 22 has two outer surfaces 22b in its own height direction Z, at least one of the two outer surfaces 22b serves as the first heat dissipation surface b1, including the upper and lower surfaces of an electrode assembly 22 both serving as the first heat dissipation surface b1, including one or two of the upper and lower surfaces of some electrode assemblies 22 serving as the first heat dissipation surface b1, the upper and lower surfaces of other electrode assemblies 22 not serving as the first heat dissipation surface b1, and the bottom surfaces of all electrode assemblies 22 serving as the first heat dissipation surface b1.

[0085] Typically, the first heat dissipation surface b1 is the bottom surface of the electrode assembly 22. Of course, it can also be the top surface of the electrode assembly 22. The shell wall facing the first heat dissipation surface b1 is the heat exchange shell wall 21a, and this heat exchange shell wall 21a is referred to as the first shell wall a1. It is understood that there can be one or two first shell walls a1, as long as they are arranged facing the first heat dissipation surface b1 in the height direction Z.

[0086] Taking the example of a cylindrical electrode assembly 22, the height direction Z of the cylindrical structure generally corresponds to its axial direction. Therefore, the first heat dissipation surface b1 is generally its axial end surface, and the tab J1 is generally located at one or both axial ends of the cylindrical structure. Taking a jelly-rolled electrode assembly 22 as an example, when the tab J1 is oriented in its height direction Z, the tab J1 can be located at one or both ends in the height direction Z, with one or both outer surfaces 22b in the height direction Z serving as the first heat dissipation surface b1.

[0087] It is understandable that for the same first shell wall a1, when there are multiple first heat dissipation surfaces b1 arranged opposite to it, a heat conducting structure 23 is set between all the first heat dissipation surfaces b1 and the first shell wall a1. At this time, the heat conducting structure 23 can be set in one piece or in a separate piece.

[0088] Typically, the tab J1 is formed by the current collecting matrix J of the electrode sheet in the electrode assembly 22. The positive tab J1 is formed by the current collecting matrix J of the positive electrode sheet 22c, and the negative tab J1 is formed by the current collecting matrix J of the negative electrode sheet 22d. The current collecting matrix J is a thin sheet structure capable of carrying active material and conducting current. The current collecting matrix J can be a copper matrix, an aluminum matrix, a stainless steel matrix, or other composite matrix, and has electrical conductivity.

[0089] Since the tab J1 is arranged in the height direction Z of the electrode assembly 22, the outer surface 22b serving as the first heat dissipation surface b1 can expose the pole piece / insulator 22e in the electrode assembly 22 (each pole piece is separated by the insulating member 22e). In this way, the heat-conducting structure 23 can contact the internal pole piece / insulator 22e of the electrode assembly 22, making it easy to dissipate the internal heat of the electrode assembly 22, and the heat exchange efficiency of the electrode assembly 22 is high.

[0090] When the thermally conductive structure 23 is connected to the first heat dissipation surface b1, it can be connected to the positive electrode sheet 22c and / or the negative electrode sheet 22d. To reduce the risk of short circuiting the positive and negative electrode sheets 22c and 22d, the thermally conductive structure 23 typically has insulating properties. When the thermally conductive structure 23 is thermally conductively connected to the positive electrode sheet 22c or the negative electrode sheet 22d, it is typically thermally conductively connected to the current collecting substrate J of the positive electrode sheet 22c or the negative electrode sheet 22d. Of course, the thermally conductive structure 23 can also be thermally conductively connected to the separator 22e exposed on the first heat dissipation surface b1.

[0091] FIG. 7 is a schematic diagram illustrating the interlayer structure of the electrode assembly 22 according to one or more embodiments.

[0092] In some embodiments, in combination with Figures 4, 6 and 7, the electrode assembly 22 includes a positive electrode sheet 22c and a negative electrode sheet 22d, and the positive electrode sheet 22c and the negative electrode sheet 22d both include a current collecting matrix J. In the electrode assembly 22 having a first heat dissipation surface b1, the current collecting matrix J of at least one of the positive electrode sheet 22c and the negative electrode sheet 22d includes a protrusion J2 protruding from the first heat dissipation surface b1, and the heat conductive structure 23 located between the first heat dissipation surface b1 and the first shell wall a1 is thermally connected to the protrusion J2.

[0093] As mentioned above, the current collecting matrix J refers to a thin sheet structure that can be used to carry active materials and conduct current. The current collecting matrix J of the positive electrode sheet 22c is usually aluminum foil, and the current collecting matrix J of the negative electrode sheet 22d is usually copper foil.

[0094] As shown in FIG5 , the protrusion J2 is a structure protruding from the first heat dissipation surface b1 in the current collecting base J. It is a part of the current collecting base J and is usually integrally formed therewith, similar to the tab J1 formed by the current collecting base J. Generally, when the current collecting base J includes the protrusion J2, the tab J1 thereof can be located at opposite ends of the height direction Z of the electrode assembly 22 from the protrusion J2. In this case, the height direction Z of the electrode assembly 22 corresponds to the width direction Y of the current collecting base J.

[0095] One or both of the current collecting substrate J of the positive electrode sheet 22c and the current collecting substrate J of the negative electrode sheet 22d have a protrusion J2 protruding from the first heat dissipation surface b1. The protrusion J2 formed by the current collecting substrate J of the positive electrode sheet 22c (defined as the first protrusion J2) and the protrusion J2 formed by the current collecting substrate J of the negative electrode sheet 22d (defined as the second protrusion J2) should be insulated to prevent short circuits. The first protrusion J2 and the second protrusion J2 can be separated by a certain distance, and the first protrusion J2 and the second protrusion J2 can also be covered with an insulating member. Generally, in order to reduce the probability of a short circuit between the current collecting substrate J of the positive electrode sheet 22c and the current collecting substrate J of the negative electrode sheet 22d, only the current collecting substrate J of the positive electrode sheet 22c or only the current collecting substrate J of the negative electrode sheet 22d is formed with a protrusion J2, and processing and forming are simpler.

[0096] Typically, the protrusion J2 on the current collecting base J is provided separately from the tab J1. In some cases, the protrusion J2 on the current collecting base J and the tab J1 can also be provided as an integral whole, that is, the tab J1 can be directly used as the protrusion J2, as long as it does not affect the electrical transmission function of the tab J1. It is understandable that the protrusions J2 of the current collecting bases J of the same polarity can be combined into a whole and then connected to the heat conducting structure 23.

[0097] Since the protrusion J2 is formed by the protrusion of the current collecting substrate J, the current collecting substrate J usually has good thermal conductivity. Therefore, the protrusion J2 has good thermal conductivity and can directly and quickly conduct the heat of the current collecting substrate J through the protrusion J2, which helps to improve the heat exchange efficiency of the electrode assembly 22.

[0098] In some embodiments, with reference to FIG. 6 , in the electrode assembly 22 having the first heat dissipation surface b1 , the tab J1 and the first heat dissipation surface b1 are disposed opposite to each other in the height direction Z of the electrode assembly 22 .

[0099] That is, the electrode assembly 22 includes only a first heat dissipation surface b1, and the tab J1 is located at one end of the electrode assembly 22 that is opposite to the first heat dissipation surface b1 in the height direction Z, the protrusion J2 is located at one end of the electrode assembly 22 in the height direction Z, and the tab J1 is located at the other end of the electrode assembly 22 in the height direction Z. In this way, the protrusion J2 and the tab J1 are separately arranged, and the traditional shell 21 structure can be used to a large extent, thereby reducing the improvement cost of the battery cell 20.

[0100] Figure 8 is a schematic diagram of the internal structure of the battery cell 20 in the embodiment shown in Figure 2. Figure 9 is an exploded view of the battery cell 20 in the embodiment shown in Figure 8. Figure 10 is a cross-sectional view of the battery cell 20 in the embodiment shown in Figure 2.

[0101] 8 and 9 , in combination with FIG. 4 , the heat-conducting structure 23 includes a heat-conducting insulating layer 23 b , which is disposed on the inner side of the first shell wall a1 and connected between the first shell wall a1 and the protrusion J2 .

[0102] The heat-conducting insulating layer 23b can be formed by coating, sputtering, or other methods of heat-conducting insulating material on the inner side of the heat exchange shell 21a. The material of the heat-conducting insulating layer 23b can be selected conventionally.

[0103] In this case, the thermally conductive insulating layer 23b forms at least a portion of the thermally conductive structure 23, which is low-cost and easy to implement. Furthermore, since the protrusion J2 increases the height dimension of the electrode assembly 22 in the height direction Z, the thermally conductive insulating layer 23b is thermally connected between the protrusion J2 and the first shell wall a1, thereby helping to reduce the height dimension of the battery cell 20 and increase the energy density of the battery cell 20.

[0104] It can be understood that when the plurality of electrode assemblies 22 have the protrusions J2 , the thermally conductive insulating layers 23 b connected between the protrusions J2 and the first shell wall a1 can exist as a whole.

[0105] In some embodiments, referring to FIG. 4 , the thickness of the thermally conductive insulating layer 23 b is L1 , and the protruding height of the protruding portion J2 is L2 , satisfying the following conditions: L1 < 3 mm, and / or L2 < 6 mm.

[0106] The thickness L1 of the thermally conductive insulating layer 23b refers to the maximum dimension of the thermally conductive insulating layer 23b in the height direction Z of the electrode assembly 22. The protrusion height L2 of the protrusion J2 refers to the maximum dimension of the protrusion J2 in the height direction Z.

[0107] Generally, the smaller L1 and L2 are, the smaller the size of the battery cell 20 in the height direction Z is, and the higher the energy density of the battery cell 20 is. Of course, if L1 and L2 are too small, it will increase the processing difficulty and cost, and will not significantly improve the heat exchange efficiency.

[0108] When L1 satisfies L1<3 mm, or L2 satisfies L2<6 mm, the energy density and processing cost of the battery cell 20 are relatively moderate, while also taking into account a certain heat exchange efficiency.

[0109] In some embodiments, L1 satisfies 0.02mm≤L1≤0.6mm, and / or L2 satisfies 1mm≤L2≤4mm. Specifically, L1 can be selected from 0.02mm, 0.03mm, 0.04mm, 0.05mm, 0.06mm, and values ​​between any two adjacent values. Specifically, L2 can be selected from 1mm, 1.5mm, 2mm, 2.5mm, 3mm, 3.5mm, 4mm, and values ​​between any two adjacent values. In this case, the battery cell 20 has an excellent energy density and a certain heat exchange efficiency.

[0110] In some embodiments, the thermally conductive insulating layer 23b includes at least one of a polyimide layer, an epoxy resin layer, a phenolic resin layer, a urea-formaldehyde resin layer, a polyetheretherketone layer, a polybenzimidazole layer, an aluminum oxide layer, a boehmite layer, and a silicon carbide layer. In this case, the thermally conductive insulating layer has good thermal conductivity and insulation properties.

[0111] Fig. 11 is a schematic diagram of a partial internal structure of the battery cell 20 in the embodiment shown in Fig. 5. Fig. 12 is a cross-sectional view of the battery cell 20 shown in Fig. 11 .

[0112] In some embodiments, referring to Figures 11 and 12, and in combination with Figures 5 and 6, at least one outer surface 22b of at least one electrode assembly 22 in the thickness direction X is a second heat dissipation surface b2, the heat exchange shell wall 21a includes a second shell wall a2, the second heat dissipation surface b2 and the second shell wall a2 are arranged facing each other in the thickness direction X, and a heat conductive structure 23 is provided between the two.

[0113] The second heat dissipation surface b2 is an outer surface 22b of the electrode assembly 22 opposite to the second shell wall a2 and with the heat conducting structure 23 disposed therebetween, and located in the thickness direction X of the electrode assembly 22 .

[0114] The outer surface 22b located in the thickness direction X of the electrode assembly 22 is defined as the thick-outer surface. The thickness direction X of the electrode assembly 22 generally corresponds to the stacking direction of the positive electrode sheet 22c, the negative electrode sheet 22d, and the separator 22e. When the electrode assembly 22 is cylindrical, the thickness direction X of the electrode assembly 22 corresponds to its radial direction, and the thick-outer surface is the circumferential surface of the cylindrical structure. When the electrode assembly 22 is square, the thickness direction X of the electrode assembly 22 can correspond to the thickness direction X of the square structure, and there can be two thick-outer surfaces.

[0115] When the electrode assembly 22 includes multiple electrodes, the thick outward surfaces of some / all of the electrode assemblies 22 can be used as the second heat dissipation surface b2, as long as all the electrode assemblies 22 have at least one second heat dissipation surface b2.

[0116] The second shell wall a2 is a shell wall in the shell 21 located in the thickness direction X of the electrode assembly 22 , and the number of the second shell wall a2 may be one or two.

[0117] Taking the wound electrode assembly 22 to form a square battery cell 20 as an example, the area of ​​the thick outer surface of the wound electrode assembly 22 in the thickness direction X is larger than the area of ​​the outer surface 22b in other directions, which is usually referred to as the large surface of the electrode assembly 22. That is, under normal circumstances, the second heat dissipation surface b2 has a larger surface area than the other outer surfaces 22b of the electrode assembly 22.

[0118] At this time, the second heat dissipation surface b2 with a larger surface area in the electrode assembly 22 is connected to the heat conductive structure 23. The contact area between the electrode assembly 22 and the second heat dissipation surface b2 is large, and the heat exchange efficiency is higher.

[0119] In some embodiments, please refer to Figure 11, a plurality of electrode assemblies 22 are configured, and the plurality of electrode assemblies 22 are arranged in sequence along their own thickness direction X, and a penetration space k is formed between each adjacent two electrode assemblies 22, and the thermal conductive structure 23 includes a first thermal conductive insulating pad 23a, and the first thermal conductive insulating pad 23a extends into each penetration space k and is connected to the outer surface 22b forming each penetration space k.

[0120] Typically, multiple electrode assemblies 22 are configured within a battery cell 20 to provide the battery cell 20 with a larger capacity and voltage. When multiple electrode assemblies 22 are configured, the thickness directions X of the electrode assemblies 22 are arranged in parallel, and the electrode assemblies 22 are arranged in sequence along their own thickness directions X. Among the multiple electrode assemblies 22, some of the electrode assemblies 22 can be arranged side by side along the thickness direction X to form a row of structures, while other portions of the electrode assemblies 22 can be arranged side by side to form another row of structures. The rows of structures can be arranged in parallel in a direction roughly perpendicular to the thickness direction X (typically the width direction Y of the electrode assembly 22, the width direction Y of the electrode assembly 22 corresponds to the length direction of the battery cell 20, and the thickness direction X of the electrode assembly 22 can correspond to the width direction Y of the battery cell 20).

[0121] The first thermally conductive insulating pad 23a is a generally sheet-shaped structure made of a thermally conductive insulating material. In the two electrode assemblies 22 arranged side by side along the thickness direction X, a through-space k is formed between the two opposing thick-outer surfaces. The first thermally conductive insulating pad 23a extends into this through-space k and contacts the two thick-outer surfaces forming the through-space k. This means that the first thermally conductive insulating pad 23a is sandwiched between the two opposing thick-outer surfaces.

[0122] It should be noted that when there are multiple penetration spaces k, the first thermally conductive insulating pad 23a extends into each penetration space k. Specifically, the thermally conductive structure 23 may include a connecting portion and multiple first thermally conductive insulating pads 23a, each of which extends into a corresponding penetration space k, and all of the first thermally conductive insulating pads 23a are connected together by the connecting portion. The thermally conductive structure 23 is connected to the heat exchange shell wall 21a via the connecting portion.

[0123] At this time, the same first thermally conductive insulating pad 23 a can be thermally connected to the thick outer surfaces of the two electrode assemblies 22 , and the thermal conductive structure 23 has a higher thermal conductivity efficiency for all electrode assemblies 22 as a whole.

[0124] In some embodiments, in combination with Figures 11 and 12, the first thermally conductive insulating pad 23a is continuously extended, and the penetration spaces k arranged in sequence along the thickness direction X of the electrode assembly 22 are located in sequence on the extension path of the first thermally conductive insulating pad 23a, and the first thermally conductive insulating pad 23a is arranged between the second heat dissipation surface b2 and the second shell wall a2.

[0125] Referring to Figure 11 , the first thermally conductive insulating pad 23a extends in a generally S-shaped curve. During this extension, it adheres to at least one thick outer surface of each electrode assembly 22. In the embodiment shown in Figure 11 , there are three electrode assemblies 22. For ease of explanation, the three electrode assemblies 22 are referred to as the first electrode assembly 22, the second electrode assembly 22, and the third electrode assembly 22 along the arrangement direction. Each electrode assembly 22 includes two thick outer surfaces: a left second outer surface 22b and a right outer surface 22b. Of all the thick outer surfaces, the thick outer surfaces at both ends in the thickness direction X serve as second heat dissipation surfaces b2.

[0126] The starting end of the first thermally conductive insulating pad 23a is arranged between the left outer surface 22b of the first electrode assembly 22 (the second heat dissipation surface b2) and one of the second shell walls a2, and extends along the left outer surface 22b of the first electrode assembly 22 to the through-space k (defined as the first through-space k) formed by the right outer surface 22b of the first electrode assembly 22 and the left outer surface 22b of the second electrode assembly 22, and then extends to the through-space k (defined as the second through-space k) formed by the right outer surface 22b of the second electrode assembly 22 and the left outer surface 22b of the third electrode assembly 22, and then the tail end of the first thermally conductive insulating pad 23a extends to the right outer surface 22b of the third electrode assembly 22 (serving as the second heat dissipation surface b2) and contacts the other second shell wall a2.

[0127] In some examples, the first thermally conductive insulating pad 23a is flexible, making it easier to wrap around each electrode assembly 22 and providing a tighter connection. In some examples, the dimensions of the first thermally conductive insulating pad 23a in the height direction Z are comparable to the dimensions of the electrode assembly 22 in the height direction Z. This maximizes the contact area between the first thermally conductive insulating pad 23a and each second heat dissipation surface b2, resulting in a higher thermal conductivity efficiency per unit area of ​​the first thermally conductive insulating pad 23a.

[0128] At this time, the first thermally conductive insulating pad 23 a can be in thermal contact with the outer surfaces 22 b of the plurality of electrode assemblies 22 in the thickness direction X along the extension path, thereby enhancing the heat exchange efficiency between the second shell wall a2 and the electrode assemblies 22 .

[0129] In some embodiments, referring to FIG. 11 , the thickness of the first thermally conductive insulating pad 23 a is L3 , satisfying: L3 < 4 mm.

[0130] The thickness L3 of the first thermally conductive insulating pad 23a refers to a dimension in a direction perpendicular to its extending direction.

[0131] The smaller the thickness L3 of the first thermally conductive insulating pad 23a is, the smaller the space it occupies inside the battery cell 20 is, which is more conducive to improving the energy density of the battery cell 20. When L3 is too small, the heat transfer capability of the first thermally conductive insulating pad 23a is lower.

[0132] When L3 is less than 4 mm, the battery cell 20 can achieve both high energy density of the battery cell 20 and high thermal conductivity efficiency of the first thermally conductive insulating pad 23 a .

[0133] In some embodiments, 0.3 mm ≤ L3 ≤ 2 mm. Specifically, L3 can be selected from 0.3 mm, 0.5 mm, 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm, and any value between adjacent values. In this case, the energy density and thermal conductivity of the battery cell are both good.

[0134] In some embodiments, referring to Figures 6 and 11 , one outer surface 22b of each electrode assembly 22 in the width direction Y serves as a third heat dissipation surface b3, and the third heat dissipation surfaces b3 of adjacent electrode assemblies 22 are disposed opposite to each other in the width direction Y. The third heat dissipation surface b3 is in surface contact with the first thermally conductive insulating pad 23a.

[0135] The outer surface 22b of the electrode assembly 22 in the width direction Y is referred to as a widthwise outer surface. Typically, there are two widthwise outer surfaces. The width direction Y, thickness direction X, and height direction Z of the electrode assembly 22 are substantially perpendicular to each other. When the electrode assembly 22 is cylindrical, its width direction Y and thickness direction X may be two perpendicular radial directions.

[0136] The third heat dissipation surface b3 is not disposed opposite the heat exchange shell wall 21a, but is in surface contact with the first thermally conductive insulating pad 23a. Specifically, referring to FIG8 , when the first thermally conductive insulating pad 23a bends and extends into each penetration space k, the first thermally conductive insulating pad 23a can extend along a wide outer surface of the electrode assembly 22 and enter the penetration space k located downstream of the wide outer surface along the extension path.

[0137] At this time, not only the contact area between the first thermally conductive insulating pad 23a and the electrode assembly 22 is increased, but also the first thermally conductive insulating pad 23a and the electrode assembly 22 are more tightly wound. The first thermally conductive insulating pad 23a can enhance the position stability of each electrode assembly 22.

[0138] Of course, when the heat-conducting structure 23 adopts a structure other than the first heat-conducting insulating pad 23 a , the heat-conducting structure 23 can also be heat-conductingly connected to the third heat dissipation surface b3 at the same time.

[0139] In some embodiments, please refer to Figure 10, and in combination with Figures 8 and 9, at least one outer surface 22b of at least one electrode assembly 22 in the width direction Y is a third heat dissipation surface b3, and the shell 21 includes a third shell wall a3. The third heat dissipation surface b3 is arranged opposite to the third shell wall a3, and a heat-conducting structure 23 is arranged between the two.

[0140] The third heat dissipation surface b3 is an outer surface 22b of the electrode assembly 22 located in the width direction Y. It can be understood that each electrode assembly 22 includes two third heat dissipation surfaces b3 disposed opposite to each other. For a wound electrode assembly 22, the third heat dissipation surface b3 is usually a curved surface.

[0141] The third shell wall a3 is a shell wall structure of the housing 21 located in the width direction Y of the electrode assembly 22. The third shell wall a3 can serve as part of the heat exchange shell wall 21a and can exchange heat with the external heat exchange structure 30. The third shell wall a3 can also not serve as the heat exchange shell wall 21a.

[0142] Specifically, a heat-conducting structure 23 may be provided between each third heat-dissipating surface b3 and the third shell wall a3 of each electrode assembly 22. Alternatively, a heat-conducting structure 23 may be provided between all third heat-dissipating surfaces b3 and the third shell wall a3 of all electrode assemblies 22. In this case, the heat-conducting structure 23 may be connected as a whole between the third shell wall a3 and all third heat-dissipating surfaces b3.

[0143] In one example, the thermally conductive structure 23 matches the contour of the third heat dissipation surface b3 due to the contact area between the third heat dissipation surface b3 and the thermally conductive structure 23. For example, in the embodiments shown in Figures 8, 9, and 10, the surface where the thermally conductive structure 23 contacts the third heat dissipation surface b3 is a circular arc surface that matches the contour of the third heat dissipation surface b3.

[0144] At this time, by setting a heat-conducting structure 23 between the third shell wall a3 and the third heat dissipation surface b3, the transmission path of the heat of the electrode assembly 22 to the shell 21 can be increased, thereby improving the degree of heat exchange between the shell 21 and the outside, which is beneficial to the heat dissipation of the battery cell 20.

[0145] In some embodiments, referring to FIG. 9 , in conjunction with FIG. 8 and FIG. 10 , a plurality of electrode assemblies 22 are provided, arranged along the thickness direction X of the electrode assemblies 22, with each adjacent electrode assemblies 22 separated to form a through-space k. The thermally conductive structure 23 includes a second thermally conductive insulating pad 23 c, a portion of which extends into each through-space k and is connected to the outer surface 22 b forming each through-space k. The remaining portion of the second thermally conductive insulating pad 23 c is disposed between the entire third heat dissipation surface b3 and the third shell wall a3.

[0146] For more information about the through-spaces k, please refer to the above description. The second thermally conductive insulating pad 23c is made of a thermally conductive insulating material and includes a first thermally conductive insulating portion c1 and a second thermally conductive insulating portion c2. The first thermally conductive insulating portion c1 of the second thermally conductive insulating pad 23c extends into each through-space k and connects to the surface of the electrode assembly 22 forming that through-space k. The second thermally conductive insulating portion c2 is positioned between the third heat dissipation surface b3 and the third shell wall a3 of each electrode assembly 22.

[0147] Taking the embodiments shown in Figures 8 to 10 as an example, when the electrode assembly 22 includes two, a first thermally conductive insulating portion c1 extends into the through-space k between the two electrode assemblies 22, and the first thermally conductive insulating portion c1 of the second thermally conductive insulating pad 23c can achieve a large-surface connection between the electrode assemblies 22, and the conduction efficiency between the electrode assemblies 22 is relatively high. In addition, the two outer surfaces 22b of each electrode assembly in the width direction Y are both third heat dissipation surfaces b3, and the second thermally conductive insulating portion c2 of the second thermally conductive insulating pad 23c is provided between the third heat dissipation surface b3 and the third shell wall a3. Among them, the first thermally conductive insulating portion c and the second thermally conductive insulating portion c2 of the second thermally conductive insulating pad 23c are generally, but not limited to, an integrated arrangement. At this time, the second thermally conductive insulating pad 23c is roughly H-shaped.

[0148] At this time, the second thermally conductive insulating pad 23c can extend into the penetration space k between the electrode assemblies 22 and thermally connect the adjacent electrode assemblies 22, which can improve the thermal conductivity between the electrode assembly 22 and the shell 21, and help improve the heat dissipation efficiency of the battery cell 20 from the internal heat to the outside.

[0149] In some embodiments, referring to FIG8 , the second thermally conductive insulating pad 23c is connected to the thermally conductive insulating layer 23b. Specifically, the bottom of the second thermally conductive insulating pad 23c is supported on the thermally conductive insulating layer 23b. This allows heat from within the electrode assembly 22 to be transferred to the external heat exchange structure 30 through the second thermally conductive insulating pad 23c, the thermally conductive insulating layer 23b, and the first shell wall a1, thereby improving the heat exchange efficiency between the electrode assembly 22 and the heat exchange structure 30.

[0150] It is easy to understand that in the embodiment of the present application, when the shell 21 includes the first shell wall a1, the second shell wall a2 and the third shell wall a3, the three walls intersect with each other and are not coplanar.

[0151] In one embodiment of the present application, a battery cell 20 includes a housing 21, at least one electrode assembly 22, and a heat-conducting structure 23. The housing 21 has a heat-exchange wall 21a, which is used to contact the heat-exchange structure 30 located outside the housing 21. Each electrode assembly 22 has a protrusion J2 protruding from its bottom surface in the height direction Z, and the protrusion J2 contacts the first housing wall a1 through a heat-conducting insulating layer 23b. The first housing wall a1 is located in the height direction Z of the housing 21 in the electrode assembly 22, and the second housing wall a2 is located in the thickness direction X of the housing 21 in the electrode assembly 22. The heat-exchange wall 21a includes a first housing wall a1, and the heat-conducting structure 23 includes a heat-conducting insulating layer 23b, which is disposed on the inner side of the first housing wall a1.

[0152] The heat exchange shell wall 21a further includes a second shell wall a2, and the heat conductive structure 23 further includes a first heat conductive insulating pad 23a, which is wound in an S-shape and extends between adjacent electrode assemblies 22, and contacts the outer surface of each electrode assembly 22 in two thickness directions and contacts the second shell wall a2; or,

[0153] The shell 21 also includes a third shell wall a3, and the heat-conducting structure 23 also includes a second heat-conducting insulating pad 23c. The second heat-conducting insulating pad 23c extends between adjacent electrode assemblies 22 and contacts the outer surfaces of each electrode assembly 22 in two width directions and contacts the third shell wall a3.

[0154] In addition, an embodiment of the present application further provides a battery 100, as shown in Figures 2 to 5 . The battery 100 includes a heat exchange structure 30 and the aforementioned battery cell 20. The heat exchange structure 30 is located outside the housing 21 and contacts the heat exchange shell wall 21a. For details about the heat exchange structure 30 and the battery cell 20, please refer to the above description and will not be repeated here. This battery 100 has all the beneficial effects of the aforementioned embodiments.

[0155] 2 , 4 , and 5 , a battery 100 includes a housing 10, a plurality of battery cells 20, and all of the battery cells 20 are supported side by side on the bottom inner wall 10a of the housing 10. A heat exchange structure 30 is disposed between adjacent battery cells 20, and / or between the bottom inner wall 10a and the battery cells 20.

[0156] The housing 10 is a component of the internal space of the battery 100 and can be made of plastic, metal or other composite materials. For an introduction to the housing 10 , please refer to the above description.

[0157] Multiple battery cells 20 can be arranged in a matrix and disposed on the bottom inner wall 10a of the housing 10. Typically, the bottom inner wall 10a of the housing 10 is located in the height direction Z of the electrode assembly 22 in the battery cells 20. When the heat exchange structure 30 is arranged between adjacent battery cells 20, specifically, between the second shell walls a2 of adjacent battery cells 20, the same heat exchange structure 30 can be used to exchange heat with the second shell walls a2 of different battery cells 20. The heat exchange path between the electrode assembly 22 and the heat exchange structure 30 is shortened by utilizing the second shell walls a2, the heat conductive structure 23 (specifically, the first thermally conductive insulating pad 23a), and the second heat dissipation surface b2.

[0158] When the heat exchange structure 30 is arranged between the bottom inner wall 10a and the bottom of all or part of the battery cell 20, the first shell wall a1 of the battery cell 20, the heat conductive structure 23 (specifically the heat conductive insulation layer 23b) and the first heat dissipation surface b1 can be used to shorten the heat exchange path between the electrode assembly 22 and the heat exchange structure 30.

[0159] At this time, a heat dissipation scheme of the battery cell 20 that matches the different heat exchange structure 30 layout schemes can be configured, and the heat exchange path between the heat exchange structure 30 and the electrode assembly 22 can be shortened through the heat exchange shell wall 21a and the heat conductive structure 23, thereby improving the heat exchange efficiency of the heat exchange structure 30 to the electrode assembly 22.

[0160] In addition, the embodiment of the present application further provides an electric device, including the battery 100, for providing electric energy. The electric device includes all the above-mentioned beneficial effects, which will not be described in detail here.

[0161] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0162] The above-described embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that a person of ordinary skill in the art may make various modifications and improvements without departing from the spirit of the present application, and these modifications and improvements fall within the scope of protection of the present application. Therefore, the scope of protection of the present patent application shall be determined by the appended claims.

Claims

1. A battery cell (20), comprising: A shell (21), the shell (21) having a heat exchange shell wall (21a), the heat exchange shell wall (21a) being used to conduct heat inside the battery cell (20) to a heat exchange structure (30) located outside the shell (21); at least one electrode assembly (22); and A heat-conducting structure (23) is contained in the shell (21), and is disposed between the electrode assembly (22) and the heat exchange shell wall (21a) for heat conduction.

2. The battery cell (20) according to claim 1, wherein: The outer surface (22b) of at least one of the electrode assemblies (22) is arranged facing the heat exchange shell wall (21a); The heat-conducting structure (23) is provided between at least one group of the outer surfaces (22b) and the heat exchange shell wall (21a) that are arranged facing each other.

3. The battery cell (20) according to claim 1 or 2, wherein: At least one outer surface (22b) of at least one electrode assembly (22) in the height direction (Z) is a first heat dissipation surface (b1), and a pole ear (J1) of the electrode assembly (22) is located at at least one end in the height direction (Z); The heat exchange shell wall (21a) comprises a first shell wall (a1), the first heat dissipation surface (b1) and the first shell wall (a1) are arranged facing each other in the height direction (Z), and the heat conduction structure (23) is arranged between the two.

4. The battery cell (20) according to claim 3, wherein: The electrode assembly (22) comprises a positive electrode sheet (22c) and a negative electrode sheet (22d), and the positive electrode sheet (22c) and the negative electrode sheet (22d) both comprise a current collecting matrix (J); In the electrode assembly (22) having the first heat dissipation surface (b1), the current collecting matrix (J) of at least one of the positive electrode sheet (22c) and the negative electrode sheet (22d) comprises a protrusion (J2) protruding from the first heat dissipation surface (b1); The heat-conducting structure (23) located between the first heat dissipation surface (b1) and the first shell wall (a1) is heat-conductingly connected to the protrusion (J2).

5. The battery cell (20) according to claim 4, wherein: In the electrode assembly (22) having the first heat dissipation surface (b1), the electrode tab (J1) and the first heat dissipation surface (b1) are arranged opposite to each other in the height direction (Z) of the electrode assembly (22).

6. The battery cell (20) according to claim 4, wherein: The heat-conducting structure (23) comprises a heat-conducting insulating layer (23b), which is arranged on the inner side surface of the first shell wall (a1) and connected between the first shell wall (a1) and the protruding portion (J2).

7. The battery cell (20) according to claim 6, wherein: The thickness of the heat-conducting insulating layer (23b) is L1, and the protruding height of the protruding portion (J2) is L2, satisfying: L1<3 mm, and / or, L2<6 mm.

8. The battery cell (20) according to claim 7, wherein: The L1 satisfies: 0.02mm≤L1≤0.6mm; and / or, the L2 satisfies: 1mm≤L2≤4mm.

9. The battery cell (20) according to claim 6, 7 or 8, wherein: The thermally conductive insulating layer (23b) comprises at least one of a polyimide layer, an epoxy resin layer, a phenolic resin layer, a urea-formaldehyde resin layer, a polyetheretherketone layer, a polybenzimidazole layer, an aluminum oxide layer, a boehmite layer, and a silicon carbide layer.

10. The battery cell (20) according to any one of claims 1 to 9, wherein: At least one outer surface (22b) of at least one of the electrode assemblies (22) in the thickness direction (X) is a second heat dissipation surface (b2); The heat exchange shell wall (21a) comprises a second shell wall (a1), the second heat dissipation surface (b2) and the second shell wall (a1) are arranged facing each other in the thickness direction (X), and the heat conduction structure (23) is arranged between the two.

11. The battery cell (20) according to claim 10, wherein: The electrode assemblies (22) are arranged in plurality; the plurality of electrode assemblies (22) are arranged along their thickness direction (X), and each two adjacent electrode assemblies (22) are spaced to form a penetration space (k); The heat-conducting structure (23) comprises a first heat-conducting insulating pad (23a), wherein the first heat-conducting insulating pad (23a) extends into each of the penetration spaces (k) and is surface-connected to the outer surface (22b) forming each of the penetration spaces (k).

12. The battery cell (20) according to claim 11, wherein: The first thermally conductive insulating pad (23a) is continuously extended, and the penetration spaces (k) arranged in sequence along the thickness direction (X) of the electrode assembly (22) are sequentially located on the extension path of the first thermally conductive insulating pad (23a); The first thermally conductive insulating pad (23a) is arranged between the second heat dissipation surface (b2) and the second shell wall (a1).

13. The battery cell (20) according to claim 11 or 12, wherein: The thickness of the first thermally conductive insulating pad (23a) is L3, satisfying: L3<4mm.

14. The battery cell (20) according to claim 13, wherein: The L3 satisfies: 0.3mm≤L3≤2mm.

15. The battery cell (20) according to any one of claims 11 to 14, wherein: One of the outer surfaces (22b) of each electrode assembly (22) in the width direction (Y) is a third heat dissipation surface (b3), and the third heat dissipation surfaces (b3) of adjacent electrode assemblies (22) are arranged opposite to each other in the width direction (Y); The third heat dissipation surface (b3) is in surface contact with the first thermally conductive insulating pad (23a).

16. The battery cell (20) according to any one of claims 1 to 15, wherein: At least one outer surface (22b) of at least one of the electrode assemblies (22) in the width direction (Y) is a third heat dissipation surface (b3); The housing (21) comprises a third housing wall (a3); the third heat dissipation surface (b3) and the third housing wall (a3) ​​are arranged facing each other, and the heat conduction structure (23) is arranged between the two.

17. The battery cell (20) according to claim 16, wherein: The electrode assemblies (22) are arranged in plurality; the plurality of electrode assemblies (22) are arranged along their thickness direction (X), and each two adjacent electrode assemblies (22) are spaced to form a penetration space (k); The heat-conducting structure (23) comprises a second heat-conducting insulating pad (23c), a portion of which extends into each of the penetration spaces (k) and is connected to the outer surface (22b) forming each of the penetration spaces (k); The remaining part of the second thermally conductive insulating pad (23c) is arranged between the third heat dissipation surface (b3) and the third shell wall (a3). between.

18. A battery (100), wherein: include: Heat exchange structure (30); and According to the battery cell (20) according to any one of claims 1 to 17, the heat exchange structure (30) is located outside the shell (21) and is in contact with the heat exchange shell wall (21a).

19. The battery (100) according to claim 18, wherein: The battery (100) further comprises a box (10), a plurality of battery cells (20) are arranged, and all of the battery cells (20) are supported side by side on the bottom inner wall (10a) of the box (10); A heat exchange structure (30) is arranged between adjacent battery cells (20), and / or the heat exchange structure (30) is arranged between the bottom inner wall (10a) and the battery cells (20).

20. An electrical device, wherein: The invention comprises a battery (100) as claimed in claim 18 or 19, wherein the battery (100) is used to provide electrical energy.

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