Battery cell, battery, electrical apparatus, and energy storage apparatus

Abstract

A battery cell, a battery, an electrical apparatus, and an energy storage apparatus. The battery cell comprises: an electrode assembly, which comprises at least two layers of stacked electrode sheets; a casing, an accommodating space being formed in the interior of the casing, the electrode assembly being located in the accommodating space, the casing comprising a first side wall and a second side wall, the first side wall being located on one side of the electrode assembly in the layer thickness direction, the plane on which the first side wall is located intersecting the plane on which the second side wall is located, and the first side wall being connected to the second side wall by means of a transition portion; and an elastic pad, which is located between the electrode assembly and the first side wall. The elastic pad is arranged between the electrode assembly and the first side wall, the electrode assembly can avoid the transition portion during expansion of the electrode assembly, and the elastic pad can also absorb a compressive force during the expansion of the electrode assembly. As a result, the risk of active material detachment caused by mutual compression and abrasion between the electrode assembly and the transition portion of the casing is more effectively reduced, thereby mitigating the phenomenon of lithium plating and prolonging the service life of a battery.

Description

Battery cells, batteries, electrical devices and energy storage devices

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] The present disclosure is based on the Chinese patent application with application number 202410255445.8, application date March 6, 2024, and invention name “Battery Cell, Battery, Electrical Device and Energy Storage Device”, and claims the priority of the Chinese patent application. The entire content of the Chinese patent application is hereby incorporated into the present disclosure as a reference. Technical Field

[0003] The present disclosure relates to the field of battery technology, and in particular to battery cells, batteries, electrical devices, and energy storage devices. Background Art

[0004] New energy batteries are being used more and more widely in life and industry. For example, new energy vehicles equipped with batteries have been widely used. In addition, batteries are also being increasingly used in energy storage fields.

[0005] In new energy vehicles equipped with batteries, they can provide full or partial propulsion. In energy storage, batteries can be installed in energy storage boxes or directly at the user's side. Extending battery life in these applications is a current research topic.

[0006] Summary of the Invention

[0007] In order to solve the above technical problems, the present disclosure provides a battery cell, a battery, an electrical device and an energy storage device capable of extending the service life.

[0008] The present disclosure is achieved through the following technical solutions.

[0009] A first aspect of the present disclosure provides a battery cell, comprising: an electrode assembly, comprising at least two layers of electrode sheets, which are stacked; a shell, forming an accommodation space inside, and the electrode assembly is located in the accommodation space, the shell comprising a first side wall and a second side wall, the first side wall being located on one side of the electrode assembly in a layer thickness direction, the plane where the first side wall is located intersecting with the plane where the second side wall is located, and the first side wall being connected to the second side wall through a transition portion; and an elastic pad being located between the electrode assembly and the first side wall.

[0010] By using the elastic pad located between the electrode assembly and the first side wall, the distance between the electrode assembly and the shell can be increased, providing the space required for the motor assembly to expand, thereby avoiding the transition part, and absorbing the extrusion force during the expansion of the electrode assembly, thereby reducing the risk of wear and tear caused by mutual extrusion between the transition part of the electrode assembly and the shell, resulting in the shedding of active materials, reducing lithium plating, and extending the service life of the battery.

[0011] In some embodiments, the transition portion has a transition fillet, and the thickness of the elastic pad is greater than the radius of the transition fillet.

[0012] By making the thickness of the elastic pad greater than the radius of the transition fillet, more space can be provided for the expansion of the electrode assembly, more effectively reducing the risk of active material falling off due to mutual squeezing and wear between the transition part of the electrode assembly and the shell, reducing lithium plating and extending the service life of the battery.

[0013] In some embodiments, the shell includes two first side walls opposite to each other along the layer thickness direction, the two first side walls are respectively located on opposite sides of the electrode assembly along the layer thickness direction, and an elastic pad is provided between each first side wall and the electrode assembly.

[0014] This allows both transition sections to be avoided simultaneously, and the respective elastic pads can absorb the expansion of the electrode assembly along the thickness direction, thereby more effectively reducing the risk of active material shedding due to mutual compression and wear between the transition section of the electrode assembly and the housing, reducing lithium deposition, and extending the battery life. In some embodiments, the housing is a flexible housing, and the elastic pad completely covers the surface of the electrode assembly facing the first side wall.

[0015] In some embodiments, the shell is a flexible shell, and the elastic pad completely covers the surface of the electrode assembly facing the first side wall.

[0016] Since the shell is a flexible shell, the flexible shell wraps the electrode assembly inside, so each adjacent side wall of the flexible shell may be connected by a transition part. The elastic pad completely covers the surface of the electrode assembly facing the first side wall, which can effectively avoid each transition part, reduce the risk of wear caused by mutual compression between the transition part of the electrode assembly and the shell, reduce lithium plating, and extend the service life of the battery.

[0017] In some embodiments, the shell is a rigid shell, and the elastic pad partially or completely covers the surface of the electrode assembly facing the first side wall.

[0018] Because the housing is rigid, the elastic pad located between the first sidewall and the electrode assembly partially covers the surface of the electrode assembly facing the first sidewall, thereby avoiding the transition portion while saving material and reducing costs. By fully covering the surface of the electrode assembly facing the first sidewall, the elastic pad can more evenly absorb the compressive force during the electrode assembly's expansion.

[0019] In some embodiments, the plane where the second side wall is located is perpendicular to the layer thickness direction, the electrode assembly is configured as a winding structure, and the electrode assembly includes a flat portion and a bent portion connected to each other, and an elastic pad is provided between the flat portion and the first side wall.

[0020] During the expansion process of the electrode assembly, the flat part is more likely to interfere and squeeze with the transition part than the bent part. Therefore, an elastic pad is provided between the flat part and the first side wall, which can effectively reduce the risk of wear caused by mutual squeezing between the electrode assembly and the transition part of the shell, reduce lithium plating, extend the service life of the battery, and at the same time reduce the number of elastic pads used and reduce costs.

[0021] In some embodiments, the electrode assembly is constructed as a laminate structure.

[0022] In some embodiments, the elastic pad is configured to be compressible along the layer thickness direction. The thickness of the elastic pad when uncompressed is T, and the thickness compressed with a surface stress of 2 MPa is T1, wherein T is greater than the radius of the transition fillet, and (T-T1) / T≥30%.

[0023] The elastic pad has a suitable compressibility ratio and thus has suitable compressibility, so that the elastic pad can absorb more of the extrusion force during the expansion of the electrode assembly, thereby more effectively reducing the risk of active material shedding caused by mutual extrusion and wear between the transition part of the electrode assembly and the shell, reducing lithium plating and extending the service life of the battery.

[0024] In some embodiments, the electrode assembly includes a tab connected to the electrode sheet, with one end of the tab extending outside the housing, thereby forming a soft-pack battery cell.

[0025] In some embodiments, one end of the shell has an opening, and the battery cell further includes: an end cover disposed at the opening, and the end cover is provided with an electrode terminal; the electrode assembly includes a tab connected to the electrode sheet, and the tab is connected to the electrode terminal.

[0026] A second aspect of the present disclosure provides a battery, comprising: a box body and a battery cell according to any one of the above embodiments, wherein the battery cell is accommodated in the box body.

[0027] A third aspect of the present disclosure provides an electrical device, which includes a battery cell or a battery according to any one of the above embodiments for providing electrical energy.

[0028] A fourth aspect of the present disclosure provides an energy storage device, comprising a battery cell or a battery according to any one of the above embodiments, wherein the battery is capable of storing electrical energy and providing electrical energy.

[0029] In the technical solution of the embodiment of the present disclosure, since an elastic pad is provided between the electrode assembly and the first side wall, the transition portion can be avoided during the expansion of the electrode assembly, and the elastic pad can also absorb the extrusion force during the expansion of the electrode assembly, thereby extending the service life of the battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] 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 disclosure. The same reference numerals are used throughout the drawings to denote the same components. In the drawings:

[0031] FIG1 is a schematic structural diagram of a vehicle provided by some embodiments of the present disclosure;

[0032] FIG2 is an exploded schematic diagram of a battery provided by some embodiments of the present disclosure;

[0033] FIG3 is an exploded schematic diagram of a battery cell provided by some embodiments of the present disclosure;

[0034] FIG4 is a schematic cross-sectional view of a battery cell provided by some embodiments of the present disclosure, wherein the elastic pad is in an uncompressed state;

[0035] FIG5 is a schematic cross-sectional view of a battery cell provided by some embodiments of the present disclosure, wherein the elastic pad is in a compressed state;

[0036] FIG6 is a schematic structural diagram of a battery cell provided by other embodiments of the present disclosure;

[0037] FIG7 is a schematic cross-sectional view of the battery cell taken along line AA in FIG6 according to some embodiments of the present disclosure;

[0038] FIG8 is a partial enlarged schematic diagram of B in FIG7 provided in some embodiments of the present disclosure;

[0039] FIG9 is an exploded schematic diagram of a battery cell with its housing removed provided by some embodiments of the present disclosure;

[0040] FIG10 is a cross-sectional view of an electrode assembly provided in accordance with some embodiments of the present disclosure.

[0041] Description of reference numerals:

[0042] 1000 vehicles; 100 batteries; 200 controllers; 300 motors;

[0043] 1 bottom plate; 2 cover; 3 vertical plate;

[0044] 10 battery cells;

[0045] 11 electrode assembly; 111 flat portion; 112 bent portion; 113 pole piece; 113a positive pole piece; 113b negative pole piece; 114 separator; 115 pole tab; 115a positive pole tab; 115b negative pole tab;

[0046] 12 housing; 121 first side wall; 122 second side wall; 123 third side wall; 12a transition portion; 12b accommodating space;

[0047] 13 end cap;

[0048] 14 electrode terminals;

[0049] 15 pressure relief valve;

[0050] 16 elastic pads;

[0051] C layer thickness direction; T, T1 thickness; R radius. DETAILED DESCRIPTION

[0052] The following embodiments of the technical solution of the present disclosure are 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 disclosure and are therefore only examples and are not intended to limit the scope of protection of the present disclosure.

[0053] 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 the present disclosure belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the present disclosure; the terms "including" and "having" and any variations thereof in the specification and claims of the present disclosure and the above-mentioned figure descriptions are intended to cover non-exclusive inclusions.

[0054] In the description of the embodiments of the present disclosure, technical terms such as "first," "second," and "third" are used solely to distinguish different objects and should not be understood to indicate or imply relative importance or to implicitly specify the quantity, specific order, or primary and secondary relationship of the technical features indicated. In the description of the embodiments of the present disclosure, "plurality" means more than two, unless otherwise specifically defined.

[0055] 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 disclosure. 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.

[0056] In the description of the embodiments of the present disclosure, the term "and / or" is simply a description of the association relationship between associated objects, indicating that three relationships can exist. For example, A and / or B can represent three situations: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in this document generally indicates that the associated objects are in an "or" relationship.

[0057] In the description of the embodiments of the present disclosure, the orientations or positional relationships indicated by technical terms such as "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", and "circumferential" are 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 disclosure and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed, operated or used in a specific orientation. Therefore, they should not be understood as limiting the embodiments of the present disclosure.

[0058] In the description of the embodiments of the present disclosure, unless otherwise expressly specified or limited, technical terms such as "installed," "connected," "connect," 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; and can refer to internal connectivity between two components or interaction between two components. Those skilled in the art can understand the specific meanings of the above terms in the embodiments of the present disclosure based on specific circumstances.

[0059] In the description of the embodiments of the present disclosure, unless otherwise clearly specified and limited, the technical term "contact" should be understood in a broad sense, and can be direct contact, contact through an intermediate medium layer, contact with essentially no interaction force between the two contacting parties, or contact with interaction force between the two contacting parties.

[0060] Hereinafter, the present disclosure will be described in detail.

[0061] Currently, new energy batteries are increasingly being used in everyday life and industry. 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 like electric bicycles, electric motorcycles, and electric cars, as well as in a variety of fields such as aerospace. As the application of power batteries continues to expand, market demand is also growing.

[0062] During the battery cycle, the volume of the battery will change. The greater the volume change of the battery, the greater the squeezing force between the battery shells or between the battery shells and the box. By adding compressible soft pads such as insulation pads or buffer pads between the battery shells or between the battery shells and the box to provide the space required for the battery volume change, the mutual squeezing between the batteries can be effectively alleviated, and the risk of thermal runaway caused by squeezing and wear of the battery can be reduced, thereby extending the battery life.

[0063] Research has found that the volume change of the battery during the cycle is mainly caused by the expansion of the electrode assembly in the shell along its thickness direction. During the expansion of the electrode assembly, the electrode assembly is easily worn due to mutual squeezing with the shell, and the active material layer at the worn part is easy to fall off, which may cause lithium precipitation. The lithium precipitation phenomenon has an adverse effect on the service life of the battery. Further research has found that the transition part (which can be called a corner) connecting the two side walls of the shell is usually a rounded transition or a chamfered transition. Because the space at the transition part is relatively cramped, the distance between the electrode assembly and the transition part is smaller. Therefore, during the expansion of the electrode assembly, it is more likely to be squeezed with the transition part to cause wear, which in turn causes the active material to fall off, causing lithium precipitation, and ultimately having an adverse effect on the service life of the battery. In a soft-pack battery whose shell is a flexible material, the shell can be formed by two flexible sheets close to each other. Therefore, there is also a risk of interference with the internal electrode assembly (especially the corner of the electrode assembly) at the bent part of the flexible sheet.

[0064] To this end, the present invention provides an elastic pad between the shell and the electrode assembly, and increases the distance between the electrode assembly and the side wall of the shell through the elastic pad, avoiding the transition part, providing the electrode assembly with the space required for expansion. At the same time, the elastic pad absorbs the expansion of the electrode assembly, thereby reducing the risk of active material falling off due to mutual compression and wear between the electrode assembly and the shell, reducing lithium plating, and extending the service life of the battery.

[0065] Based on such a design concept, the present disclosure provides a battery cell, including an electrode assembly, including at least two layers of electrode sheets, which are stacked; a shell, which forms an accommodation space inside, and the electrode assembly is located in the accommodation space, the shell includes a first side wall and a second side wall, the first side wall is located on one side of the electrode assembly in the layer thickness direction, the plane where the first side wall is located intersects with the plane where the second side wall is located, and the first side wall is connected to the second side wall through a transition portion; an elastic pad, located between the electrode assembly and the first side wall.

[0066] The elastic pad located between the electrode assembly and the first side wall can not only increase the distance between the electrode assembly and the shell, avoiding the transition part to provide the space required for the expansion of the motor assembly, but also absorb the expansion of the electrode assembly, thereby reducing the risk of active material falling off due to mutual compression and wear between the transition part of the electrode assembly and the shell, reducing lithium plating, and extending the service life of the battery.

[0067] The present disclosure also provides a battery comprising one or more battery cells. The battery can reduce the risk of active material shedding due to mutual compression and wear between the transition portion of the electrode assembly and the housing, thereby reducing lithium plating and extending the battery life.

[0068] In the embodiment of the present disclosure, the battery cell may be a secondary battery. A secondary battery refers to a battery cell that can be continuously used by activating active materials by charging after the battery cell is discharged.

[0069] The battery cells may be lithium-ion batteries, sodium-ion batteries, sodium-lithium-ion batteries, lithium metal batteries, sodium metal batteries, lithium-sulfur batteries, magnesium-ion batteries, nickel-hydrogen batteries, nickel-cadmium batteries, lead-acid batteries, etc., which are not limited in the embodiments of the present disclosure.

[0070] A battery cell typically includes an electrode assembly. This assembly includes a positive electrode, a negative electrode, and a separator. During the charge and discharge process of a battery cell, active ions (such as lithium ions) are inserted and removed between the positive and negative electrodes. The separator, placed between the positive and negative electrodes, prevents short circuits between the positive and negative electrodes while allowing the active ions to pass through.

[0071] In some embodiments, the positive electrode may be a positive electrode sheet, which may include a positive electrode current collector and a positive electrode active material disposed on at least one surface of the positive electrode current collector.

[0072] As an example, the positive electrode current collector has two surfaces facing each other in its thickness direction, and the positive electrode active material is provided on either or both of the two facing surfaces of the positive electrode current collector.

[0073] As an example, the positive electrode current collector may be a metal foil or a composite current collector. For example, as the metal foil, aluminum or stainless steel with a silver surface treatment, stainless steel, copper, aluminum, nickel, carbon electrode, carbon, nickel or titanium, etc. may be used. The composite current collector may include a polymer material base layer and a metal layer. The composite current collector may be formed by forming a metal material (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0074] As an example, the positive electrode active material may include at least one of the following materials: lithium-containing phosphates, lithium transition metal oxides, and their respective modified compounds. However, the present disclosure is not limited to these materials, and other traditional materials that can be used as battery positive electrode active materials may also be used. These positive electrode active materials may be used alone or in combination of two or more. Examples of lithium-containing phosphates may include, but are not limited to, at least one of lithium iron phosphate (such as LiFePO4 (also referred to as LFP)), a composite material of lithium iron phosphate and carbon, lithium manganese phosphate (such as LiMnPO4), a composite material of lithium manganese phosphate and carbon, lithium iron manganese phosphate, and a composite material of lithium iron manganese phosphate and carbon.

[0075] In some embodiments, a positive electrode may be a metal foam. The metal foam may be nickel foam, copper foam, aluminum foam, alloy foam, or carbon foam, among others. When a metal foam is used as the positive electrode, the surface of the metal foam may or may not be provided with a positive electrode active material. For example, a lithium source material, potassium metal, or sodium metal may be filled and / or deposited within the metal foam, where the lithium source material is lithium metal and / or a lithium-rich material.

[0076] In some embodiments, the negative electrode may be a negative electrode sheet, and the negative electrode sheet may include a negative electrode current collector.

[0077] As an example, the negative electrode current collector may be a metal foil, a metal foam, or a composite current collector. For example, as the metal foil, aluminum or stainless steel treated with silver, stainless steel, copper, aluminum, nickel, carbon electrode, carbon, nickel, or titanium, etc. may be used. The composite current collector may include a polymer material base layer and a metal layer. The metal foam may be nickel foam, copper foam, aluminum foam, alloy foam, or carbon foam, etc. The composite current collector may be formed by forming a metal material (copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.). In some embodiments, the material of the positive electrode current collector may be aluminum, and the material of the negative electrode current collector may be copper.

[0078] In some embodiments, the electrode assembly further includes a separator disposed between the positive electrode and the negative electrode.

[0079] In some embodiments, the separator is a separator. The present disclosure has no particular limitation on the type of separator, and any known separator with a porous structure having good chemical stability and mechanical stability can be selected.

[0080] As an example, the main material of the isolation membrane can be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene, polyvinylidene fluoride, and ceramics.

[0081] In some embodiments, the separator is a solid electrolyte, which is disposed between the positive electrode and the negative electrode and serves to transport ions and isolate the positive and negative electrodes.

[0082] In some embodiments, the battery cell further includes an electrolyte, which acts as a conductor of ions between the positive and negative electrodes. This disclosure does not specifically limit the type of electrolyte, and the electrolyte may be selected based on needs. The electrolyte may be liquid, gel, or solid.

[0083] In some embodiments, the electrode assembly is a wound structure, wherein the positive electrode sheet and the negative electrode sheet are wound into the wound structure.

[0084] In some embodiments, the electrode assembly is a laminate structure.

[0085] As an example, multiple positive electrode sheets and multiple negative electrode sheets can be provided respectively, and the multiple positive electrode sheets and the multiple negative electrode sheets can be alternately stacked.

[0086] As an example, a plurality of positive electrode sheets may be provided, and the negative electrode sheet may be folded to form a plurality of stacked folded segments, with a positive electrode sheet being sandwiched between adjacent folded segments.

[0087] As an example, both the positive electrode sheet and the negative electrode sheet are folded to form a plurality of stacked folded segments.

[0088] As an example, a plurality of separators may be provided, each of which is disposed between any adjacent positive electrode sheets or negative electrode sheets.

[0089] As an example, the separator may be provided continuously, and may be provided between any adjacent positive electrode sheets or negative electrode sheets by folding or winding.

[0090] In some embodiments, the shape of the electrode assembly can be cylindrical, flat, or polygonal.

[0091] In some embodiments, the electrode assembly is provided with tabs that can conduct current from the electrode assembly. The tabs include a positive tab and a negative tab.

[0092] In some embodiments, a battery cell may include a housing. The housing is used to encapsulate components such as the electrode assembly and the electrolyte. The housing may be a steel housing, an aluminum housing, a plastic housing (e.g., polypropylene), a composite metal housing (e.g., a copper-aluminum composite housing), or an aluminum-plastic film.

[0093] As an example, the battery cell can be a cylindrical battery cell, a prismatic battery cell, a soft-pack battery cell or a battery cell of other shapes. The prismatic battery cell includes a square-shell battery cell, a blade-shaped battery cell, a polygonal battery, such as a hexagonal battery, etc. There is no special limitation in the present disclosure.

[0094] In some embodiments, the housing includes an end cap and a shell. The shell has an opening, and the end cap closes the opening to form a sealed space for accommodating the electrode assembly, electrolyte, and other substances. The shell may have one or more openings. One or more end caps may also be provided.

[0095] In some embodiments, the housing is provided with at least one electrode terminal, which is electrically connected to the tab. The electrode terminal may be directly connected to the tab or indirectly connected to the tab via an adapter component. The electrode terminal may be provided on the end cap or on the housing.

[0096] In some embodiments, the housing is provided with a pressure relief mechanism for releasing the internal pressure of the battery cell.

[0097] The battery mentioned in the embodiments of the present disclosure may include one or more battery cells to provide a single physical module with higher voltage and capacity. When there are multiple battery cells, the multiple battery cells are connected in series, in parallel or in hybrid through a busbar.

[0098] In some embodiments, the battery may be a battery module. When there are multiple battery cells, the multiple battery cells are arranged and fixed to form a battery module.

[0099] In some embodiments, the battery may be a battery pack, which includes a case and battery cells, wherein the battery cells or battery modules are housed in the case.

[0100] In some embodiments, the box body can be used as a part of the chassis structure of the vehicle. For example, part of the box body can become at least a part of the floor of the vehicle, or part of the box body can become at least a part of the cross beam and longitudinal beam of the vehicle.

[0101] In some embodiments, the battery may be an energy storage device, including an energy storage container, an energy storage cabinet, and the like.

[0102] The battery provided by the embodiments of the present disclosure can be used, but is not limited to, in electrical devices such as energy storage devices, vehicles, ships, or aircraft. Because the battery provided by the embodiments of the present disclosure can reduce the risk of active material shedding due to mutual compression and wear between the transition portion of the electrode assembly and the housing, and thus reduce lithium deposition, it can extend the service life of electrical devices such as energy storage devices, vehicles, ships, or aircraft.

[0103] The embodiments of the present disclosure provide an electrical device including the above-mentioned battery or battery pack for providing electrical energy. The electrical device may be, but is not limited to, a mobile phone, a tablet, a laptop computer, an electric toy, an electric tool, a battery-powered vehicle, an electric car, a ship, a spacecraft, etc. The electric toy may include a fixed or mobile electric toy, such as a game console, an electric car toy, an electric ship toy, and an electric airplane toy, etc. The spacecraft may include an airplane, a rocket, a space shuttle, and a spacecraft, etc.

[0104] In the following embodiments, for the convenience of description, the electric device of one embodiment of the present disclosure is taken as an example of a vehicle 1000. The following description is made with reference to the accompanying drawings.

[0105] FIG1 is a schematic structural diagram of a vehicle 1000 provided in some embodiments of the present disclosure. The vehicle 1000 may be a fuel vehicle, a gas vehicle or a new energy vehicle. The new energy vehicle may be a pure electric vehicle, a hybrid vehicle or an extended-range vehicle, etc. As shown in FIG1 , a battery 100 is provided inside the vehicle 1000. The battery 100 may be provided at the bottom, head or tail of the vehicle 1000. The battery 100 may be used to power the vehicle 1000. For example, the battery 100 may serve as an operating power source for the vehicle 1000. The vehicle 1000 may further include a controller 200 and a motor 300. The controller 200 is used to control the battery 100 to power the motor 300, for example, for starting, navigating and operating power requirements of the vehicle 1000 during driving.

[0106] In some embodiments of the present disclosure, the battery 100 can serve not only as an operating power source for the vehicle 1000 , but also as a driving power source for the vehicle 1000 , replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000 .

[0107] Figure 2 is a schematic exploded perspective view of a battery 100 according to an embodiment of the present disclosure. As shown in Figure 2, battery 100 comprises a base plate 1, a cover 2, a vertical plate 3, and at least one battery cell 10. The cover 2 covers the base plate 1, thereby forming a space between the base plate 1 and the cover 2 to accommodate the battery cell 10.

[0108] In the battery 100, there may be multiple battery cells 10, and the multiple battery cells 10 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 10. The multiple battery cells 10 may be directly connected in series, in parallel, or in a hybrid connection, and then the entire battery cell 10 may be placed in the storage space formed by the base plate 1 and the cover 2. Of course, the battery 100 may also be a battery module formed by first connecting multiple battery cells 10 in series, in parallel, or in a hybrid connection, and then the multiple battery modules are further connected in series, in parallel, or in a hybrid connection to form an entire battery cell, which is then stored in the storage space formed by the base plate 1 and the cover 2. The battery 100 may also include other structures. For example, the battery 100 may also include a busbar component for electrically connecting the multiple battery cells 10.

[0109] In the embodiment of the present disclosure, the battery cell may be a secondary battery. A secondary battery refers to a battery cell that can be continuously used by activating active materials by charging after the battery cell is discharged.

[0110] The battery cells may be lithium-ion batteries, sodium-ion batteries, sodium-lithium-ion batteries, lithium metal batteries, sodium metal batteries, lithium-sulfur batteries, magnesium-ion batteries, nickel-hydrogen batteries, nickel-cadmium batteries, lead-acid batteries, etc., which are not limited in the embodiments of the present disclosure.

[0111] Hereinafter, some embodiments of the present disclosure will be described in detail with reference to FIG. 3 to FIG. 10 .

[0112] Figure 3 is a schematic diagram of the decomposition of a battery cell provided in some embodiments of the present disclosure; Figure 4 is a schematic diagram of the cross-section of a battery cell provided in some embodiments of the present disclosure, wherein the elastic pad is in an uncompressed state; Figure 5 is a schematic diagram of the cross-section of a battery cell provided in some embodiments of the present disclosure, wherein the elastic pad is in a compressed state; Figure 6 is a schematic diagram of the structure of a battery cell provided in other embodiments of the present disclosure; Figure 7 is a schematic diagram of the AA cross-section of the battery cell in Figure 6 provided in some embodiments of the present disclosure; Figure 8 is a schematic diagram of the enlarged part B in Figure 7 provided in some embodiments of the present disclosure; Figure 9 is a schematic diagram of the decomposition of a battery cell with the shell removed provided in some embodiments of the present disclosure; Figure 10 is a cross-sectional view of the electrode assembly provided in some embodiments of the present disclosure.

[0113] The present disclosure provides a battery cell 10, comprising an electrode assembly 11, a housing 12, and an elastic pad 16. The electrode assembly 11 includes at least two layers of electrode sheets 113, which are stacked. The housing 12 defines an interior accommodation space 12b, within which the electrode assembly 11 is located. The housing 12 includes a first sidewall 121 and a second sidewall 122. The first sidewall 121 is located on one side of the electrode assembly 11 in a thickness direction C. The plane of the first sidewall 121 intersects the plane of the second sidewall 122, and the first sidewall 121 is connected to the second sidewall 122 via a transition portion 12a. The elastic pad 16 is located between the electrode assembly 11 and the first sidewall 121.

[0114] 3 and 10 , the electrode assembly 11 may include a multi-layer electrode sheet 113 , wherein the multi-layer electrode sheet 113 includes a positive electrode sheet 113 a and a negative electrode sheet 113 b .

[0115] The electrode assembly 11 further includes tabs 115 connected to the electrode sheet 113. The tabs 115 include a positive tab 115a and a negative tab 115b.

[0116] At least two electrode sheets (positive electrode sheet 113a and negative electrode sheet 113b) of the electrode assembly 11 are stacked together to form a stacked structure with a certain thickness. The stacked structure can be a wound stacked structure or a laminated stacked structure. The wound stacked structure includes a flat portion 111 and a bent portion 112.

[0117] The housing 12 includes a storage space for accommodating the electrode assembly 11. The housing 12 can be of various structural forms. In some embodiments, the housing 12 can be a rigid housing, such as a steel shell, an aluminum shell, a plastic shell (such as polypropylene), a composite metal shell (such as a copper-aluminum composite shell), etc. In other embodiments, the housing 12 can be a soft housing, such as an aluminum-plastic shell (aluminum-plastic film). Regardless of whether the housing 12 is a rigid shell or a soft shell, the electrode assembly 11 therein can be a wound laminated structure or a laminated laminated structure.

[0118] When the housing 12 is a rigid housing, the housing 12 may be a hollow structure with one side open, and the end cap 13 is fitted over the opening of the housing 12 to form a sealed connection, thereby forming a sealed accommodation space for accommodating the electrode assembly 11 and the electrolyte. Of course, the housing 12 may also be a hollow structure with two sides open, with an end cap 13 fitted over each opening to form a sealed connection, thereby forming a sealed accommodation space for accommodating the electrode assembly 11 and the electrolyte.

[0119] When the shell 12 is a soft shell, the electrode assembly 11 can be encapsulated in the accommodating space by an aluminum-plastic film, thereby forming a soft-pack battery.

[0120] The shell 12 may be in various shapes, which may be determined according to the specific shape of the electrode assembly 11. For example, a cylinder, a prism, and the prism may include a cube, a cuboid, a polygon, and the like.

[0121] The housing 12 may include a plurality of walls, including a first sidewall 121 and a second sidewall 122. The first sidewall 121 is located on one side of the electrode assembly 11 in the thickness direction C. For example, the first sidewall 121 faces the side of the electrode assembly 11 in the thickness direction.

[0122] The plane of the first side wall 121 intersects the plane of the second side wall 122, which can be understood as an angle between the first side wall 121 and the second side wall 122. For example, the plane of the first side wall 121 and the plane of the second side wall 122 are perpendicular to each other.

[0123] The first side wall 121 is connected to the second side wall 122 via the transition portion 12a, which can be understood as the first side wall 121 and the second side wall 122 being adjacent to each other and connected via the transition portion 12a. The transition portion 12a can be rounded or chamfered.

[0124] Since the distance between the electrode assembly 11 located in the shell 12 and the transition portion 12a is small, during the expansion process of the electrode assembly 11, the edge of the electrode assembly 11 adjacent to the transition portion 12a will interfere, squeeze and wear with the transition portion 12a, causing the active material layer on the electrode assembly 11 to fall off, making lithium deposition likely to occur, and ultimately having an adverse effect on the service life of the battery.

[0125] Through the elastic pad 16 located between the electrode assembly 11 and the first side wall 121, the elastic pad 16 can increase the distance between the electrode assembly and the shell, providing the space required for the electrode assembly 11 to expand, thereby avoiding the transition portion 12a, and the elastic pad can also absorb the expansion of the electrode assembly, thereby reducing the risk of wear caused by mutual compression between the transition portion of the electrode assembly and the shell, reducing lithium plating, and extending the service life of the battery.

[0126] In some embodiments, the elastic pad 16 may be made of a material that is chemically resistant, insulating, and elastic, such as rubber.

[0127] In some embodiments, referring to FIG. 4 and FIG. 8 , the transition portion 12 a has a transition fillet, and the thickness T of the elastic pad 16 is greater than the radius R of the transition fillet.

[0128] The elastic pad 16 has a certain degree of compressibility when squeezed, and the thickness of the elastic pad 16 can be understood as the thickness T of the elastic pad 16 when it is not compressed.

[0129] By making the thickness T of the elastic pad 16 greater than the radius of the transition fillet, the elastic pad 16 can provide a larger avoidance space for the expansion of the electrode assembly to avoid the transition part, so that the elastic pad can absorb more of the extrusion force during the expansion of the electrode assembly, thereby more effectively reducing the risk of active material falling off due to mutual extrusion and wear between the transition part of the electrode assembly and the shell, reducing lithium plating, and extending the service life of the battery.

[0130] In some embodiments, referring to Figures 4 and 5, the elastic pad 16 is configured to be compressible along the layer thickness direction C, the thickness of the elastic pad 16 when uncompressed is T (shown in Figure 4), and the thickness compressed with a surface stress of 2 MPa is T1 (shown in Figure 5), wherein T is greater than the radius R of the transition fillet, and (T-T1) / T≥30%.

[0131] By ensuring that (T-T1) / T is ≥ 30%, the elastic pad 16 has a suitable compressibility ratio, so that the elastic pad 16 can absorb more of the extrusion force during the expansion of the electrode assembly 11, thereby more effectively reducing the risk of active material falling off due to mutual extrusion and wear between the transition part of the electrode assembly and the shell, reducing lithium plating, and extending the service life of the battery.

[0132] In some embodiments, the shell 12 includes two first side walls 121 opposite to each other along the layer thickness direction C. The two first side walls 121 are respectively located on opposite sides of the electrode assembly 11 along the layer thickness direction C, and an elastic pad 16 is arranged between each first side wall 121 and the electrode assembly 11.

[0133] It can be understood that each first side wall 121 is transitionally connected to the second side wall 122 via a transition portion 12a. The two first side walls 121 face two side surfaces of the electrode assembly 11 along the layer thickness direction respectively.

[0134] Since the electrode assembly 11 mainly expands along its layer thickness direction C, elastic pads 16 are respectively provided between the two first side walls 121 on opposite sides of the layer thickness direction of the electrode assembly 11 and the electrode assembly 11, which can avoid the two transition parts 12a at the same time, and absorb the expansion of the electrode assembly 11 along the layer thickness direction through their respective elastic pads 16, thereby more effectively reducing the risk of active material falling off due to mutual extrusion and wear between the transition parts of the electrode assembly and the shell, reducing lithium plating, and extending the service life of the battery.

[0135] As an example, referring to Figures 3 and 4, the shell 12 is a square rigid shell. The shell 12 includes two first side walls 121 opposite to each other along the thickness direction C of the electrode assembly 11, two third side walls 123 adjacent to and perpendicular to each first side wall 121, and a second side wall 122 (also referred to as a bottom wall) adjacent to and connected to the two first side walls 121. The two first side walls 121, one second side wall 122, and two third side walls 123 together constitute an accommodating space 12b with an opening. Among the side walls of the shell 12, at least two first side walls 121 are respectively connected to the second side wall 122 through a transition portion 12a. For example, each first side wall 121 is respectively connected to the second side wall 122 through a transition portion 12a, and each first side wall 121 is respectively connected to the third side wall 123 through a transition portion 12a.

[0136] In some embodiments, the first side wall 121 may be the wall with the largest area among the side walls of the housing 12 .

[0137] The electrode assembly 11 can be formed into a wound stack structure by one or more windings, and the electrode assembly 11 is accommodated in the accommodation space 12b. The electrode assembly 11 includes two side surfaces located on opposite sides along the layer thickness direction, one of which faces one first sidewall 121, and the other faces the other first sidewall 121. In some embodiments, the side of the electrode assembly 11 facing the first sidewall 121 is the side with the largest area among the side surfaces of the electrode assembly 11.

[0138] Elastic pads 16 are respectively provided between each first side wall 121 and the side surface of the electrode assembly 11 so as to avoid the two transition portions 12 a respectively, and the respective elastic pads 16 absorb the squeezing force during the expansion process of the electrode assembly 11 along the layer thickness direction.

[0139] In some embodiments, the plane where the second side wall 122 is located is perpendicular to the layer thickness direction C, the electrode assembly 11 is configured as a winding structure, and the electrode assembly 11 includes a flat portion 111 and a bent portion 112 connected to each other, and an elastic pad 16 is provided between the flat portion 111 and the first side wall.

[0140] During the expansion process of the electrode assembly 11, the flat portion 111 is more likely to interfere with and squeeze the transition portion 12a than the bent portion 112. Therefore, an elastic pad 16 is provided between the flat portion 111 and the first side wall 121, which can effectively reduce the risk of wear caused by mutual squeezing between the electrode assembly and the transition portion of the shell, reduce lithium plating, extend the service life of the battery, and at the same time reduce the number of elastic pads 16 used and reduce costs.

[0141] In some embodiments, the housing 12 is a rigid housing, and the elastic pad 16 partially or completely covers the surface of the electrode assembly 11 facing the first sidewall 121. The rigid housing can be, for example, a steel housing, an aluminum housing, a plastic housing (such as polypropylene), a composite metal housing (such as a copper-aluminum composite housing), etc.

[0142] The elastic pad 16 partially covers the surface of the electrode assembly 11 facing the first sidewall 121. The elastic pad 16 may be located at any position on the surface of the electrode assembly 11 facing the first sidewall 121, for example, in the central area or near the central area of ​​the surface of the electrode assembly 11 facing the first sidewall 121. The number of elastic pads 16 may be one or more, for example, one elastic pad 16 covers the central area of ​​the surface of the electrode assembly 11 facing the first sidewall 121, or a plurality of elastic pads 16 may cover the central area of ​​the surface of the electrode assembly 11 facing the first sidewall 121.

[0143] The elastic pad 16 completely covers the surface of the electrode assembly 11 facing the first side wall 121 , and the edge of the elastic pad 16 is flush with the edge of the surface of the electrode assembly 11 facing the first side wall 121 , or the edge of the elastic pad 16 exceeds the edge of the surface of the electrode assembly 11 facing the first side wall 121 .

[0144] Because the housing 12 is rigid, the elastic pad 16 located between the first sidewall 121 and the electrode assembly 11 can avoid the transition portion 12a. The elastic pad 16 partially covers the surface of the electrode assembly 11 facing the first sidewall 121, saving material and reducing costs. By fully covering the surface of the electrode assembly 11 facing the first sidewall 121, the elastic pad 16 can more evenly absorb the compressive force during the electrode assembly's expansion.

[0145] In some embodiments, referring to Figures 3 and 10, one end of the shell 12 has an opening, and the battery cell further includes: an end cover 13, which is arranged at the opening, and the end cover 13 is provided with an electrode terminal 14; the electrode assembly 11 includes a tab 115 connected to the electrode sheet 113, and the tab is connected to the electrode terminal 14.

[0146] The tabs 115 include a positive tab 115a and a negative tab 115b. The electrode terminal 14 includes a positive terminal and a negative terminal. The positive terminal is connected to the positive tab 115a, and the negative terminal is connected to the negative tab 115b. The end cap 13 may also be provided with a pressure relief valve 15.

[0147] 6-9 , the housing 12 is a flexible housing, and the elastic pad 16 completely covers the surface of the electrode assembly 11 facing the first sidewall 121. The flexible housing can be made of a soft material capable of wrapping the electrode assembly 11, such as an aluminum-plastic film.

[0148] The elastic pad 16 completely covers the surface of the electrode assembly 11 facing the first side wall 121 , and the edge of the elastic pad 16 is flush with the edge of the surface of the electrode assembly 11 facing the first side wall 121 , or the edge of the elastic pad 16 exceeds the edge of the surface of the electrode assembly 11 facing the first side wall 121 .

[0149] Since the shell 12 is a flexible shell, the flexible shell wraps the electrode assembly 11 inside, so each adjacent side wall of the flexible shell may be connected by a transition portion 12a. The elastic pad 16 completely covers the surface of the electrode assembly 11 facing the first side wall 121, which can effectively avoid each transition portion 12a, reduce the risk of wear caused by mutual compression between the transition portion of the electrode assembly and the shell, reduce lithium plating, and extend the service life of the battery.

[0150] In some embodiments, referring to Figures 6 and 9 , the electrode assembly 11 includes a tab 115 connected to the electrode sheet 113 (shown in Figure 9 ). One end of the tab 115 extends outside the housing 12 , thereby constituting the battery cell 10 as a pouch cell. The tabs 115 include a positive tab 115a and a negative tab 115b.

[0151] A specific example of the embodiment of the present disclosure will be described below. As shown in FIG. 5 to FIG. 8 , the battery cell 10 is a soft-pack battery cell, including an electrode assembly 11 , a shell 12 and an elastic pad 16 .

[0152] The electrode assembly 11 includes at least two layers of electrode sheets, which are stacked. The electrode assembly 11 can be a rectangular parallelepiped with a wound stacking structure or a laminated stacking structure.

[0153] The housing 12 defines a housing space 12b. The housing 12 may be made of an aluminum-plastic film to encapsulate the electrode assembly 11 within the housing space 12b. The housing 12 may be rectangular and include two opposing first side walls 121, two opposing second side walls 122, and two opposing third side walls (not shown). The first side walls 121, the second side walls 122, and the third side walls are substantially perpendicular to each other and connected by respective transition portions 12a.

[0154] The electrode assembly 11 includes two opposing side surfaces along the layer thickness direction C. These side surfaces may be the largest of the side surfaces of the electrode assembly 11. The first side walls 121 face the two side surfaces, respectively. An elastic pad 16 is disposed between each first side wall 121 and the side surface of the electrode assembly 11, wherein the elastic pad 16 completely covers the side surface. Completely covering the side surface means that the outer contour of the elastic pad 16 is not smaller than the outer contour of the side surface.

[0155] The transition portion 12a has rounded corners, and the thickness T of the elastic pad 16 when uncompressed is greater than the radius R of the rounded corners. The elastic pad 16 can simultaneously possess the following properties: electrolyte resistance; insulation; and a compressibility of no less than 30% under a large surface stress of 2 MPa. The compressibility ratio refers to the ratio of the amount of compression of the elastic pad 16 (the difference between the uncompressed thickness T and the compressed thickness T1 under a large surface stress of 2 MPa) to the uncompressed thickness T.

[0156] Through the elastic pad 16 located between the electrode assembly 11 and the first side wall, the elastic pad 16 can increase the distance between the electrode assembly 11 and the shell 12, providing the space required for the electrode assembly 11 to expand, thereby avoiding the transition portion 12a, and the elastic pad can also absorb the expansion of the electrode assembly, thereby reducing the risk of wear caused by mutual compression between the transition portion of the electrode assembly and the shell, reducing lithium plating, and extending the service life of the battery.

[0157] The embodiment of the present disclosure further provides a battery 100 , comprising: a box body and a battery cell 10 as mentioned in any of the above embodiments, wherein the battery cell 10 is accommodated in the box body.

[0158] The embodiments of the present disclosure further provide an electrical device, comprising a battery cell 10 or a battery 100 as mentioned in any of the above embodiments for providing electrical energy.

[0159] An embodiment of the present disclosure further provides an energy storage device, comprising a battery cell or a battery as provided above, wherein the battery is capable of storing electrical energy and providing electrical energy.

[0160] The above embodiments are only used to illustrate the technical solutions of the present disclosure, rather than to limit them. Although the present disclosure 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 disclosure, and they should all be included in the scope of the claims and description of the present disclosure. 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 disclosure 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, comprising: The electrode assembly comprises at least two layers of electrode sheets, wherein the at least two layers of electrode sheets are stacked; a shell, forming an accommodation space therein, the electrode assembly being located in the accommodation space, the shell comprising a first side wall and a second side wall, the first side wall being located on one side of the electrode assembly in a thickness direction, the plane where the first side wall is located intersecting with the plane where the second side wall is located, and the first side wall being connected to the second side wall via a transition portion; An elastic pad is located between the electrode assembly and the first side wall.

2. The battery cell according to claim 1, wherein: The transition portion has a transition fillet, and the thickness of the elastic pad is greater than the radius of the transition fillet.

3. The battery cell according to claim 1 or 2, wherein: The shell includes two first side walls that are opposite to each other along the layer thickness direction, and the two first side walls are respectively located on two opposite sides of the electrode assembly along the layer thickness direction. The elastic pad is disposed between each of the first side walls and the electrode assembly.

4. The battery cell according to any one of claims 1 to 3, wherein: The shell is a flexible shell, and the elastic pad completely covers the surface of the electrode assembly facing the first side wall.

5. The battery cell according to any one of claims 1 to 3, wherein: The shell is a rigid shell, and the elastic pad partially or completely covers the surface of the electrode assembly facing the first side wall.

6. The battery cell according to any one of claims 1 to 5, wherein: The plane where the second side wall is located is perpendicular to the layer thickness direction, The electrode assembly is configured as a wound stacked structure. The electrode assembly includes a flat portion and a bent portion connected to each other. The elastic pad is provided between the flat portion and the first side wall.

7. The battery cell according to any one of claims 1 to 5, wherein: The electrode assembly is constructed as a laminated structure.

8. The battery cell according to any one of claims 2 to 7, wherein: The elastic pad is configured to be compressible along the layer thickness direction. The thickness of the elastic pad when uncompressed is T, and the thickness compressed with a surface stress of 2 MPa is T1, wherein T is greater than the radius of the transition fillet, and (T-T1) / T≥30%.

9. The battery cell according to claim 4, wherein: The electrode assembly includes a tab connected to the electrode sheet, and one end of the tab extends out of the shell.

10. The battery cell according to claim 5, wherein One end of the housing has an opening, The battery cell further comprises: an end cap, disposed at the opening, wherein the end cap is provided with an electrode terminal; The electrode assembly includes a tab connected to the electrode sheet, and the tab is connected to the electrode terminal.

11. A battery comprising: A box body and a battery cell according to any one of claims 1 to 10, wherein the battery cell is accommodated in the box body. 12 . An electrical device comprising the battery cell according to claim 1 or the battery according to claim 11 for providing electrical energy. 13 . An energy storage device comprising the battery cell according to claim 1 or the battery according to claim 11 , wherein the battery is capable of storing and providing electrical energy.

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