Battery cell, battery device, and electric device

Abstract

The present application provides a battery cell, a battery device, and an electric device. The battery cell comprises a casing, an electrode assembly, and a spacer. The casing comprises a first wall and a second wall arranged opposite to each other in a first direction. The electrode assembly is accommodated in the casing and carried on the first wall. The electrode assembly comprises an electrode sheet. The spacer is accommodated in the casing and arranged in a second direction with the electrode assembly, the second direction is parallel to the thickness direction of the electrode sheet, the first direction intersects the second direction, the spacer is configured to be elastically deformable under the action of an external force, the spacer is provided with at least one channel, two ends of the channel in the extension direction thereof respectively form a first port and a second port on the surface of the spacer, and the first port and the second port are spaced apart by a preset distance in the first direction.

Description

Battery cells, battery packs and electrical devices Technical Field

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

[0002] With the development of new energy technologies, batteries are being used more and more widely, for example in mobile phones, laptops, electric vehicles, electric cars, electric airplanes, electric ships, electric toy cars, electric toy ships, electric toy airplanes, and power tools.

[0003] In the development of battery technology, improving the performance of individual battery cells is a continuous research direction. Summary of the Invention

[0004] In view of the above problems, this application provides a battery cell, a battery device, and an electrical device that can effectively improve the performance of the battery cell.

[0005] In a first aspect, embodiments of this application provide a battery cell, which includes a housing, an electrode assembly, and a spacer. The housing includes a first wall and a second wall disposed opposite to each other along a first direction. The electrode assembly is housed within the housing and supported by the first wall, and includes electrode sheets. The spacer is housed within the housing and disposed with respect to the electrode assembly along a second direction, which is parallel to the thickness direction of the electrode sheets. The first direction intersects the second direction. The spacer is configured to elastically deform under external force. The spacer has at least one channel, and the two ends of the channel along its extension direction respectively form a first port and a second port on the surface of the spacer. The first port and the second port have a predetermined distance between them in the first direction.

[0006] The aforementioned technical solution utilizes a capillary effect in its channel, allowing the electrolyte to be drawn into the channel. As the electrode assembly expands and compresses the spacer, the spacer deforms, discharging the electrolyte from the channel. Furthermore, the first and second ports have a predetermined distance in the first direction, enabling the channel to transport the electrolyte in that direction, increasing the electrolyte's wetting range and reducing the impact of insufficient electrolyte wetting on the electrode assembly. This effectively improves the performance of the individual battery cells.

[0007] In some embodiments of the first aspect, the area S1 of the cross-section of the channel perpendicular to the extension direction satisfies the relationship: 0.2 mm. 2 ≤S1≤180mm 2 .

[0008] The above technical solution, by setting the area S1 of the cross-section of the channel perpendicular to the extension direction within the above range, can meet the requirements of the capillary effect of the channel while reducing the difficulty of channel fabrication to a certain extent.

[0009] In some embodiments of the first aspect, the area S1 satisfies the relationship: 0.8 mm 2 ≤S1≤28mm 2 .

[0010] This can further improve the channel's ability to adsorb electrolyte while also mitigating the difficulty of preparation.

[0011] In some embodiments of the first aspect, the second port is located on one end face of the spacer along the first direction near the second wall.

[0012] This allows the electrolyte to more easily reach the portion of the electrode assembly near the second wall, further improving the wetting effect of the electrolyte on this portion of the electrode assembly near the second wall.

[0013] In some embodiments of the first aspect, the first port is located on one end face of the spacer along a first direction near the first wall.

[0014] The above technical solution can improve the smoothness of the channel's electrolyte intake process, thereby significantly reducing the potential risk that the channel cannot obtain sufficient electrolyte.

[0015] In some embodiments of the first aspect, the channel extends in a straight line along a first direction.

[0016] This allows for a reduction in flow path and flow resistance while maintaining the same wetting range of the electrolyte in the first direction, thereby improving the electrolyte delivery efficiency.

[0017] In some embodiments of the first aspect, the number of channels is at least two, and the at least two channels are spaced apart along a direction intersecting the extension direction.

[0018] By further increasing the number of channels, the electrolyte delivery efficiency can be further improved, which in turn helps to further improve the performance of the battery cells.

[0019] In some embodiments of the first aspect, the cross-section of the channel perpendicular to its own extension direction is circular.

[0020] The circular cross-section minimizes energy loss during electrolyte flow, allowing for smooth and rapid electrolyte transport within the channel. Furthermore, the circular cross-section design reduces the formation of sharp corners or dead zones, minimizing the risk of electrolyte stagnation or impaired flow, thus further improving electrolyte transport efficiency.

[0021] In some embodiments of the first aspect, the electrode assembly includes at least two electrodes, each including a first electrode and a second electrode, the first and second electrodes having opposite polarities. The second electrode covers the first electrode along its thickness direction, and a spacer covers the second electrode along a second direction.

[0022] When the electrode assembly expands, it presses against the spacer, and the spacer exerts a reaction force on the electrode assembly. The spacer covers the second electrode along the second direction, preventing the edges of the spacer from pressing against the electrode. This reduces the risk of stress concentration and damage to the electrode caused by pressure exerted by the spacer edges, thereby further improving the reliability of the battery cell.

[0023] In some embodiments of the first aspect, the elastic modulus of the spacer is 0.1 MPa-10 MPa.

[0024] The above technical solution, by setting the elastic modulus of the spacer within the aforementioned range, enables the spacer to meet the requirements for buffering the expansion of the electrode assembly while improving the structural stability of the spacer to a certain extent.

[0025] In some embodiments of the first aspect, the elastic modulus of the spacer is 0.2 MPa-5 MPa.

[0026] It can further improve the buffering effect of the spacer on the expansion of the electrode assembly and the balance between the structural stability of the spacer.

[0027] In some embodiments of the first aspect, a spacer is disposed between the electrode assembly and the housing.

[0028] Placing the spacer between the electrode assembly and the housing facilitates installation and directly reduces the stress on the housing when the electrode assembly expands, effectively reducing the risk of housing deformation.

[0029] In some embodiments of the first aspect, the number of electrode assemblies is at least two, the at least two electrode assemblies are arranged along the second direction, and a spacer is disposed between two adjacent electrode assemblies.

[0030] When a spacer is placed between two adjacent electrode assemblies, it can both support and buffer the two adjacent electrode assemblies, and also separate them, effectively preventing them from squeezing each other after expansion, thus improving the reliability of the battery cell. In addition, it can reduce the impact on heat conduction between the electrode assembly and the casing, helping to improve the heat exchange efficiency of the battery cell.

[0031] In some embodiments of the first aspect, the spacer is further provided with a through hole that penetrates the spacer along the second direction.

[0032] This allows the electrolyte to directly contact the electrode assembly through the through-holes, thereby increasing the area of ​​the direct contact interface between the electrolyte and the electrode assembly and thus helping to further improve the performance of the battery cell.

[0033] In some embodiments of the first aspect, the through holes and channels are spaced apart from each other. This not only reduces the impact of the introduction of through holes on the capillary effect of the channels, but also reduces the overall fabrication difficulty of the spacers, thus helping to reduce costs.

[0034] In some embodiments of the first aspect, the dimension d1 of the spacer along the second direction satisfies the relationship: 1mm≤d1≤20mm.

[0035] The above technical solution, by setting the dimension d1 of the spacer along the second direction within the above range, enables the spacer to meet the requirements for the expansion absorption effect of the electrode assembly, while reducing the internal space occupied by the spacer in the battery cell and improving the energy density of the battery cell.

[0036] In some embodiments of the first aspect, the dimension d1 satisfies the relationship: 2mm≤d1≤8mm.

[0037] It can further improve the balance between the expansion absorption of the electrode assembly by the spacer and the energy density of the battery cell.

[0038] In some embodiments of the first aspect, the electrode assembly is a wound structure, and the electrode includes a straight portion and a bent portion, the bent portion being connected to both ends of the straight portion along a third direction, the first direction, the second direction and the third direction being perpendicular to each other.

[0039] The above technical solution, by setting spacers on the large-area side of the electrode assembly, provides relatively large space for the spacers, reducing the difficulty of spacer placement and helping to improve the fabrication complexity of the battery cell while reducing costs. Furthermore, it can further improve the effect of squeezing out the electrolyte, thereby further increasing the electrolyte wetting range.

[0040] In some embodiments of the first aspect, the electrode assembly includes at least two electrodes, which are stacked along a second direction.

[0041] In the above technical solution, the second direction is the expansion direction of the electrode assembly, and the spacer and the electrode assembly are arranged along the second direction, so that the spacer can buffer the expansion of the electrode assembly, and under the pressure of the expansion of the electrode assembly on the spacer, the electrolyte located in the channel can be further driven to flow out.

[0042] In some embodiments of the first aspect, the electrode assembly has a wound structure and is cylindrical, with spacers arranged around it. This allows the spacers to better adapt to the structure of the cylindrical battery cell.

[0043] In some embodiments of the first aspect, the electrode includes a positive electrode, which includes a positive electrode active material, which includes at least one of a sodium-containing transition metal oxide, a Prussian blue compound, and a polyanionic compound.

[0044] Positive electrode sheets containing sodium-containing positive electrode active materials have a high expansion rate. Therefore, by setting spacers, the stress on the electrode assembly during expansion can be effectively reduced, the deformation of the casing can be reduced, the problem of high expansion of battery cells during charging and discharging can be alleviated, and the service life of battery cells can be improved.

[0045] In some embodiments of the first aspect, the battery cell is a metal battery cell.

[0046] Metal battery cells have a high expansion rate. Therefore, by setting spacers, the stress on the electrode assembly during expansion can be effectively reduced, the deformation of the casing can be reduced, the problem of high expansion during charging and discharging of battery cells can be alleviated, and the service life of battery cells can be improved.

[0047] Secondly, this application provides a battery device that includes a battery cell provided in any of the embodiments of the first aspect.

[0048] Thirdly, this application provides an electrical device that includes a battery cell provided in any embodiment of the first aspect or a battery device provided in any embodiment of the second aspect, wherein the battery cell or battery device is used to store or provide electrical energy.

[0049] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description

[0050] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of this application. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0051] Figure 1 is a schematic diagram of the vehicle structure provided in some embodiments of this application;

[0052] Figure 2 is an exploded structural diagram of a battery device provided in some embodiments of this application;

[0053] Figure 3 is a schematic diagram of the structure of a battery module provided in some embodiments of this application;

[0054] Figure 4 is a schematic diagram of the exploded structure of a battery cell provided in some embodiments of this application;

[0055] Figure 5 is a front view structural diagram of a battery cell provided in some embodiments of this application;

[0056] Figure 6 is a schematic diagram of the cross-sectional structure along CC in Figure 5;

[0057] Figure 7 is a three-dimensional structural schematic diagram of a spacer for a battery cell provided in some embodiments of this application;

[0058] Figure 8 is a top view of the spacer of a battery cell provided in some embodiments of this application;

[0059] Figure 9 is a schematic diagram of the cross-sectional structure along AA in Figure 8;

[0060] Figure 10 is a front view structural schematic diagram of a spacer for a battery cell provided in some embodiments of this application;

[0061] Figure 11 is a schematic diagram of the cross-sectional structure along BB in Figure 10;

[0062] Figure 12 is a schematic front view of another battery cell structure provided in some embodiments of this application;

[0063] Figure 13 is a schematic diagram of the cross-sectional structure along DD in Figure 12.

[0064] The reference numerals in the detailed embodiments are as follows: 1. Vehicle; 2. Battery device; 3. Controller; 4. Motor; 5. Housing; 5a. First housing section; 5b. Second housing section; 6. Battery module; 7. Battery cell; 10. Housing; 11. First wall; 12. Second wall; 20. Electrode assembly; 30. Spacer; 31. Channel; 311. First port; 322. Second port; 32. Through hole; X. First direction; Y. Second direction; Z. Third direction. Detailed Implementation

[0065] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0066] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used in the specification of this application is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms "comprising" and "having," and any variations thereof, in the specification, claims, and foregoing drawings of this application are intended to cover non-exclusive inclusion. The terms "first," "second," etc., in the specification, claims, or foregoing drawings of this application are used to distinguish different objects, rather than to describe a specific order or hierarchy.

[0067] In this application, the reference to "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment that is mutually exclusive with other embodiments.

[0068] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "attachment" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0069] In this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, in this application, the character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0070] In the embodiments of this application, the same reference numerals denote the same components, and for the sake of brevity, detailed descriptions of the same components are omitted in different embodiments. It should be understood that the thickness, length, width, and other dimensions of various components in the embodiments of this application shown in the accompanying drawings, as well as the overall thickness, length, width, and other dimensions of the integrated device, are merely illustrative and should not constitute any limitation on this application.

[0071] In this application, "multiple" means two or more (including two).

[0072] In this application, the term "parallel" includes not only the case of absolute parallelism, but also the case of approximate parallelism as commonly understood in engineering; similarly, "perpendicular" includes not only the case of absolute perpendicularity, but also the case of approximate perpendicularity as commonly understood in engineering.

[0073] In this application, the battery cell may include a lithium-ion secondary battery cell, a lithium-ion primary battery cell, a lithium-sulfur battery cell, a sodium-lithium-ion battery cell, a sodium-ion battery cell, or a magnesium-ion battery cell, etc., and the embodiments of this application are not limited thereto. The battery cell may be cylindrical, flat, cuboid, or other shapes, etc., and the embodiments of this application are not limited thereto.

[0074] With the development of new energy technologies, batteries are being used more and more widely, for example in mobile phones, laptops, electric vehicles, electric cars, electric airplanes, electric ships, electric toy cars, electric toy ships, electric toy airplanes, and power tools.

[0075] In the development of battery technology, improving the performance of individual battery cells is a continuous research direction. The performance of a single battery cell refers to at least one of the following: charge / discharge rate, cycle life, or reliability.

[0076] In related technologies, due to gravity, the electrolyte will accumulate at the bottom of the battery cell, causing the electrolyte level to be lower than the top edge of the electrode assembly. This results in some electrode sheets located at the top of the electrode assembly not being fully immersed in the electrolyte, which will affect the charge / discharge rate or cycle life of the battery cell.

[0077] Based on the above considerations, this application designs a battery cell, which includes a casing, an electrode assembly, and a spacer. The casing includes a first wall and a second wall disposed opposite to each other along a first direction. The electrode assembly is housed within the casing and supported by the first wall, and the electrode assembly includes electrode sheets. The spacer is housed within the casing and disposed with respect to the electrode assembly along a second direction, which is parallel to the thickness direction of the electrode sheets. The first direction intersects the second direction. The spacer is configured to elastically deform under external force. The spacer has at least one channel, and the two ends of the channel along its extension direction form a first port and a second port on the surface of the spacer, respectively. The first port and the second port have a predetermined distance between them in the first direction.

[0078] The aforementioned technical solution utilizes a capillary effect in its channel, allowing the electrolyte to be drawn into the channel. As the electrode assembly expands and compresses the spacer, the spacer deforms, discharging the electrolyte from the channel. Furthermore, the first and second ports have a predetermined distance in the first direction, enabling the channel to transport the electrolyte in that direction, increasing the electrolyte's wetting range and reducing the impact of insufficient electrolyte wetting on the electrode assembly. This effectively improves the performance of the individual battery cells.

[0079] The battery cells described in this application are applicable to battery devices and electrical equipment using battery devices. Electrical equipment can be devices that use battery devices as a power source or various energy storage systems that use battery devices as energy storage elements. Electrical equipment can be, but is not limited to, mobile phones, tablets, laptops, electric toys, power tools, electric vehicles, electric cars, ships, spacecraft, etc. Electric toys can include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc. Spacecraft can include airplanes, rockets, space shuttles, and spacecraft, etc.

[0080] For ease of explanation, the following embodiments use a vehicle as an example of electrical equipment.

[0081] Figure 1 is a schematic diagram of the structure of a vehicle provided in some embodiments of this application.

[0082] As shown in Figure 1, a battery device 2 is installed inside the vehicle 1. The battery device 2 can be located at the bottom, front, or rear of the vehicle 1. The battery device 2 can be used to power the vehicle 1; for example, the battery device 2 can serve as the operating power source for the vehicle 1.

[0083] The vehicle 1 may also include a controller 3 and a motor 4. The controller 3 is used to control the battery device 2 to supply power to the motor 4, for example, for the power needs of the vehicle 1 during starting, navigation and driving.

[0084] In some embodiments of this application, the battery device 2 can not only serve as the operating power source for the vehicle 1, but also as the driving power source for the vehicle 1, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1.

[0085] Figure 2 is a schematic diagram of the exploded structure of a battery device provided in some embodiments of this application.

[0086] In some embodiments, the battery device 2 may include one or more battery cell assemblies for providing voltage and capacity.

[0087] A battery cell assembly may include multiple battery cells (not shown in Figure 2), which are connected in series, parallel, or mixed connection via a busbar. Mixed connection refers to multiple battery cells being connected in both series and parallel connections.

[0088] A battery cell can be a rechargeable battery cell, which refers to a battery cell that can be recharged after being discharged to activate the active materials and continue to be used.

[0089] As an example, a single battery cell can be a lithium-ion battery cell, a sodium-ion battery cell, a sodium-lithium-ion battery cell, a lithium metal battery cell, a sodium metal battery cell, a lithium-sulfur battery cell, a magnesium-ion battery cell, a nickel-metal hydride battery cell, a nickel-cadmium battery cell, a lead-acid battery cell, etc.

[0090] As an example, a battery cell can be a prismatic battery cell, a pouch battery cell, or a battery cell of other shapes. Prismatic battery cells include prismatic battery cells, blade-shaped battery cells, and multi-prismatic battery cells, such as hexagonal prismatic battery cells.

[0091] In some embodiments, a battery cell assembly is typically formed by arranging multiple battery cells; as an example, a battery cell assembly can be a battery module 6, which is formed by arranging and fixing multiple battery cells into a single module. As an example, a battery module 6 can be formed by bundling multiple battery cells together with cable ties.

[0092] In some embodiments, the battery device 2 may be a battery pack, which includes a housing 5 and one or more battery cell assemblies housed within the housing 5. As an example, the battery cell assembly may be a battery module 6, which can be housed within the housing by securing the battery module 6 to the housing. Alternatively, the battery cell assembly may be housed within the housing by directly securing multiple battery cells to the housing.

[0093] In some embodiments, the housing 5 is used to house individual battery cells, and the housing 5 can have various structures.

[0094] In some embodiments, the housing 5 may include a first housing 5a and a second housing 5b. The first housing 5a and the second housing 5b are fastened together to form a closed space inside the housing 5 to house the battery cell assembly. Here, "closed" refers to covering or closing, and can be either sealed or unsealed. The first housing may be a top cover or a bottom plate.

[0095] In some embodiments, the housing 5 may include a top cover, a frame, and a bottom plate. The top cover and bottom plate are respectively connected to the frame, forming an enclosed space inside the housing to accommodate individual battery cells. As an example, the frame may include multiple side beams.

[0096] In some embodiments, the housing 5 may be part of the vehicle's chassis structure. For example, a portion of the housing 5 may be at least a portion of the vehicle's floor, or a portion of the housing 5 may be at least a portion of the vehicle's crossbeams and longitudinal beams.

[0097] In some embodiments, the battery device 2 may be an energy storage device.

[0098] Energy storage devices can be used in energy storage power stations, wind power generation systems, solar power generation systems, mobile power systems, or temporary power supply systems. Energy storage devices can store electrical energy as needed and output it when appropriate. For example, energy storage devices can store electrical energy during off-peak hours and provide power to relevant users or electrical equipment during peak hours.

[0099] In some embodiments, the energy storage device includes an energy storage container, an energy storage cabinet, etc.

[0100] Figure 3 is a schematic diagram of the structure of a battery module provided in some embodiments of this application.

[0101] In some embodiments, as shown in FIG3, there are multiple battery cells 7, which are first connected in series, parallel, or mixed to form a battery module 6. The multiple battery modules 6 are then connected in series, parallel, or mixed to form a whole and housed in a casing.

[0102] Multiple battery cells 7 in battery module 6 can be electrically connected through a busbar to achieve parallel, series, or mixed connection of multiple battery cells 7 in battery module 6. There can be one or more busbars, each used to electrically connect at least two battery cells 7.

[0103] This application provides a battery cell that includes a housing and an electrode assembly housed within the housing.

[0104] In some embodiments, the outer casing may be a steel casing, an aluminum casing, or a composite metal casing (such as a copper-aluminum composite casing).

[0105] The outer shell can be a hollow structure, with an internal cavity for accommodating the electrode assembly and electrolyte.

[0106] In some embodiments, the casing of the battery cell is a cylindrical casing, a square casing, a prismatic casing, or a casing of other shapes.

[0107] In some embodiments, the housing includes a housing and an end cap, the housing having an opening and the end cap being connected to the housing and covering the opening;

[0108] The housing is a component used to fit the end cap to form the internal cavity of the battery cell. The formed internal cavity can be used to house the electrode assembly, electrolyte, and other components.

[0109] The housing and end cap can be separate components. For example, an opening can be provided on the housing, and the end cap can be used to close the opening to form an internal cavity for the battery cell.

[0110] The housing can come in various shapes and sizes, such as cuboid or cylindrical. Specifically, the shape of the housing can be determined based on the specific shape and size of the electrode assembly. The housing can be made of various materials, such as copper, iron, aluminum, stainless steel, and aluminum alloy.

[0111] The shape of the end cap can be adapted to the shape of the housing to fit the housing. The material of the end cap can be the same as or different from that of the housing. Optionally, the end cap can be made of a material with a certain degree of hardness and strength (such as copper, iron, aluminum, stainless steel, aluminum alloy, etc.), so that the end cap is not easily deformed when subjected to compression and impact, enabling the battery cell to have higher structural strength and improve reliability.

[0112] The end caps are attached to the housing by welding, bonding, snap-fitting, or other means.

[0113] The housing may be open at one end or at both ends. In some examples, the housing may be a structure with an opening on one side, with one end cap fitting over the housing. In other examples, the housing may be a structure with openings on both sides, with two end caps fitting over the two openings of the housing, respectively.

[0114] Electrode assemblies are the components within a single battery cell where electrochemical reactions occur. The casing may contain one or more electrode assemblies.

[0115] In some embodiments, the electrode assembly includes a positive electrode, a negative electrode, and a separator, wherein the positive electrode and the negative electrode have opposite polarities, and the separator separates the positive electrode and the negative electrode.

[0116] At least a portion of the separator is located between the positive and negative electrode plates. During the charging and discharging of a single battery cell, active ions (such as lithium ions) repeatedly insert and extract between the positive and negative electrode plates. The separator, positioned between the positive and negative electrode plates, serves to prevent short circuits between the positive and negative electrodes while allowing active ions to pass through.

[0117] In some embodiments, the positive electrode may include a positive current collector and a positive electrode film layer disposed on at least one surface of the positive current collector.

[0118] As an example, the positive current collector has two surfaces opposite each other in its own thickness direction, and the positive electrode film layer is disposed on either or both of the two opposite surfaces of the positive current collector.

[0119] As an example, the positive current collector can be a metal foil, a conductive polymer material, a carbon material, or a composite current collector. For example, as a metal foil, pure metals, alloys, or surface-treated metals can be used, including but not limited to stainless steel, copper, aluminum, nickel, nickel alloys, titanium, or silver. The composite current collector may include a polymer material base layer and a metal layer. The composite current collector can be formed by forming a metal material (aluminum, aluminum alloys, nickel, nickel alloys, titanium, titanium alloys, silver, and silver alloys, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0120] As an example, the positive electrode film layer includes a positive electrode active material, which may include at least one of the following materials: lithium phosphate, lithium transition metal oxide, and their respective modified compounds. However, this application is not limited to these materials, and other conventional materials that can be used as positive electrode active materials for batteries may also be used. These positive electrode active materials may be used alone or in combination of two or more. Examples of lithium phosphate include, but are not limited to, at least one of lithium iron phosphate (such as LiFePO4 (also referred to as LFP)), lithium iron phosphate and carbon composites, lithium manganese phosphate (such as LiMnPO4), lithium manganese phosphate and carbon composites, lithium iron manganese phosphate, and lithium iron manganese phosphate and carbon composites. Examples of lithium transition metal oxides include, but are not limited to, lithium cobalt oxide (such as LiCoO2), lithium nickel oxide (such as LiNiO2), lithium manganese oxide (such as LiMnO2, LiMn2O4), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, and lithium nickel cobalt manganese oxide (such as LiNi). 1 / 3 Co 1 / 3 Mn 1 / 3 O2 (also known as NCM) 333 LiNi 0.5 Co 0.2 Mn 0.3 O2 (also known as NCM) 523 LiNi 0.5 Co 0.25 Mn 0.25 O2 (also known as NCM) 211 LiNi 0.6 Co 0.2 Mn 0.2 O2 (also known as NCM) 622 LiNi 0.8 Co 0.1 Mn 0.1 O2 (also known as NCM) 811 ), lithium nickel cobalt aluminum oxide (such as LiNi) 0.8 Co 0.15 Al 0.05At least one of O2 and its modified compounds. Modified compounds refer to substances obtained by modification methods such as doping or coating based on the above-mentioned substances.

[0121] In some embodiments, the negative electrode may include a negative current collector.

[0122] As an example, the negative electrode current collector can be a metal foil, a conductive polymer material, a carbon material, or a composite current collector. For example, as a metal foil, pure metals, alloys, or surface-treated metals can be used, including but not limited to stainless steel, copper, aluminum, nickel, nickel alloys, titanium, or silver. The composite current collector may include a polymer material substrate and a metal layer. The composite current collector can be formed by forming a metal material (copper, copper alloys, nickel, nickel alloys, titanium, titanium alloys, silver, and silver alloys, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0123] As an example, the negative electrode sheet may include a negative electrode current collector and a negative electrode film layer disposed on at least one surface of the negative electrode current collector.

[0124] As an example, the negative electrode current collector has two surfaces opposite each other in its own thickness direction, and the negative electrode film layer is disposed on either or both of the two opposite surfaces of the negative electrode current collector.

[0125] As an example, the negative electrode film layer includes a negative electrode active material, which may be a negative electrode active material known in the art for use in battery cells. As an example, the negative electrode active material may include at least one of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, and lithium titanate, etc. Silicon-based materials may be selected from at least one of elemental silicon, silicon oxide compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. Tin-based materials may be selected from at least one of elemental tin, tin oxide compounds, and tin alloys. However, this application is not limited to these materials, and other conventional materials that can be used as negative electrode active materials in battery cells may also be used. These negative electrode active materials may be used alone or in combination of two or more.

[0126] In some embodiments, the positive current collector can be made of aluminum, and the negative current collector can be made of copper.

[0127] In some embodiments, the separator includes a separator membrane. The separator membrane in this application can be any known porous membrane with good chemical and mechanical stability.

[0128] As an example, the main material of the separator can be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene, polyvinylidene fluoride, and ceramics. The separator can be a single-layer film or a multi-layer composite film, without particular limitation. When the separator is a multi-layer composite film, the materials of each layer can be the same or different.

[0129] Inorganic particle coating, organic particle coating, or organic / inorganic composite coating can also be applied to the surface of the separator.

[0130] The separator can be a single component located between the positive and negative electrodes, or it can be attached to the surface of the positive or negative electrode.

[0131] In some embodiments, the separator is a solid electrolyte. The solid electrolyte is disposed between the positive and negative electrode plates, serving both to transport ions and to isolate the positive and negative electrodes.

[0132] In some embodiments, the battery cell further includes an electrolyte, which acts as a conductor of ions between the positive and negative electrodes. The electrolyte used in this application can be selected according to requirements. The electrolyte can be liquid, gel, or solid.

[0133] In some embodiments, the liquid electrolyte includes an electrolyte salt and a solvent.

[0134] In some embodiments, the electrolyte salt may be selected from at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluorooxalate borate, lithium dioxalate borate, lithium difluorodioxalate phosphate, and lithium tetrafluorooxalate phosphate.

[0135] In some embodiments, the solvent may be selected from at least one of ethylene carbonate, propylene carbonate, methyl ethyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, butyl carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, sulfolane, dimethyl sulfone, methyl ethyl sulfone, and diethyl sulfone. The solvent may also be an ether solvent. Ether solvents may include one or more of ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, 1,3-dioxolane, tetrahydrofuran, methyl tetrahydrofuran, diphenyl ether, and crown ethers.

[0136] In some embodiments, the electrolyte may optionally include additives. For example, additives may include negative electrode film-forming additives, positive electrode film-forming additives, and additives that can improve certain properties of the battery cell, such as additives that improve the overcharge / fast charge performance of the battery cell, additives that improve the high-temperature performance of the battery cell, and additives that improve the low-temperature performance of the battery cell.

[0137] In some embodiments, the gel electrolyte comprises a polymer as a backbone network and can be used in conjunction with an ionic liquid-lithium salt.

[0138] In some embodiments, the solid electrolyte includes a polymer solid electrolyte, an inorganic solid electrolyte, and a composite solid electrolyte.

[0139] As an example, the polymers of polymeric solid electrolytes may include polyethers (polyoxyethylene), polysiloxanes, polycarbonates, polyacrylonitrile, polyvinylidene fluoride, polymethyl methacrylate, monoionic polymers, polyionic liquids, cellulose, etc.

[0140] As an example, inorganic solid electrolytes can be one or more of the following: oxide solid electrolytes (crystalline perovskite, sodium superconducting ion conductor, garnet, amorphous LiPON thin film), sulfide solid electrolytes (crystalline lithium superconducting ion conductor (lithium germanium phosphorus sulfide, silver sulfide germanium ore), amorphous sulfides), halide solid electrolytes, nitride solid electrolytes, and hydride solid electrolytes.

[0141] As an example, composite solid electrolytes are formed by adding inorganic solid electrolyte fillers to polymer solid electrolytes.

[0142] In some embodiments, the electrode assembly can be a wound structure, a stacked structure, or a hybrid structure of wound and stacked.

[0143] In some implementations, the electrode assembly is a wound structure. The positive and negative electrode sheets are wound into a wound structure.

[0144] In some implementations, the electrode assembly is a stacked structure.

[0145] As an example, multiple positive and negative electrode plates can be set, with multiple positive and multiple negative electrode plates stacked alternately. As an example, multiple positive electrode plates can be set, and negative electrode plates are folded to form multiple stacked folded segments, with a positive electrode plate sandwiched between adjacent folded segments.

[0146] As an example, both the positive and negative electrode plates are folded to form multiple stacked folded segments.

[0147] As an example, multiple separators can be provided, each positioned between any adjacent positive or negative electrode plates.

[0148] As an example, the separators can be continuously arranged, either by folding or rolling between any adjacent positive or negative electrode plates.

[0149] In some embodiments, the electrode assembly can be cylindrical, flat, or polygonal, etc.

[0150] In some embodiments, the positive current collector may include a positive tab, and the negative current collector may include a negative tab. The positive and negative tabs can be used to transmit current. As an example, at least a portion of the positive tab is not coated with a positive film layer, and at least a portion of the negative tab is not coated with a negative film layer.

[0151] In some embodiments, the electrode assembly is a wound structure. The positive electrode tab is wound multiple turns along the winding direction. Optionally, the end of the positive electrode tab is bent by a flattening or smoothing process to form a multi-layered structure stacked in the axial direction of the electrode assembly. Optionally, the positive electrode tab is annular.

[0152] In some embodiments, the negative electrode tab is wound multiple turns along the winding direction. Optionally, the end of the negative electrode tab is bent by a flattening or smoothing process to form a multi-layered structure stacked in the axial direction of the electrode assembly. The negative electrode tab is annular.

[0153] In some embodiments, the electrode assembly includes an electrode body. As an example, the electrode body includes a positive electrode film, a portion of the positive electrode current collector covered by the positive electrode film, a negative electrode film, a portion of the negative electrode current collector covered by the negative electrode film, and a separator.

[0154] The positive and negative tabs can be led out from the same end of the electrode body, or they can be led out from opposite ends of the electrode body. At least a portion of the positive tab protrudes to the outside of the insulating member, and at least a portion of the negative tab protrudes to the outside of the insulating member.

[0155] In some embodiments, a battery cell includes a positive electrode lead and a negative electrode lead, wherein the positive electrode lead is electrically connected to a positive electrode plate and the negative electrode lead is electrically connected to a negative electrode plate.

[0156] The positive and negative leads are used to connect to the external circuit to enable charging or discharging of the battery cells.

[0157] In some embodiments, the positive lead-out portion includes a positive terminal. At least a portion of the positive terminal is exposed to the outside of the battery cell to facilitate connection with a busbar.

[0158] As an example, the positive terminal may be a separately molded component that is mounted on the housing. Alternatively, the positive terminal may also be part of the housing.

[0159] In some examples, the positive terminal is directly connected to the positive plate; in other examples, the positive terminal and the positive plate are indirectly connected through other conductive structures, such as a positive adapter plate.

[0160] In some embodiments, the positive terminal is attached to the end cap by welding, riveting, snap-fitting, or other means.

[0161] In some embodiments, the negative lead-out portion includes a negative terminal. At least a portion of the negative terminal is exposed to the outside of the battery cell to facilitate connection with a busbar.

[0162] As an example, the negative terminal can be a separately molded component that is mounted on the housing. Alternatively, the negative terminal can also be part of the housing.

[0163] In some examples, the negative terminal is directly connected to the negative electrode plate; in other examples, the negative lead-out section also includes other conductive structures connecting the negative terminal and the negative electrode plate, such as a negative electrode adapter plate.

[0164] In some embodiments, the negative terminal is attached to the end cap by welding, riveting, snap-fitting, or other means.

[0165] Figure 4 is an exploded view of a battery cell according to some embodiments of this application; Figure 5 is a front view of a battery cell according to some embodiments of this application; Figure 6 is a cross-sectional view of Figure 5 along CC; Figure 7 is a three-dimensional view of a spacer for a battery cell according to some embodiments of this application; Figure 8 is a top view of a spacer for a battery cell according to some embodiments of this application; Figure 9 is a cross-sectional view of Figure 8 along AA; Figure 10 is a front view of a spacer for a battery cell according to some embodiments of this application; and Figure 11 is a cross-sectional view of Figure 10 along BB.

[0166] Referring again to Figures 4 to 11, this embodiment of the application provides a battery cell 7, which includes a housing 10, an electrode assembly 20, and a spacer 30. The housing 10 includes a first wall 11 and a second wall 12 disposed opposite to each other along a first direction X. The electrode assembly 20 is housed within the housing 10 and supported by the first wall 11, and includes an electrode sheet. The spacer 30 is housed within the housing 10 and disposed with respect to the electrode assembly 20 along a second direction Y, which is parallel to the thickness direction of the electrode sheet. The first direction X intersects with the second direction Y. The spacer 30 is configured to elastically deform under external force. The spacer 30 has at least one channel 31, and the two ends of the channel 31 along its own extending direction form a first port 311 and a second port 312 on the surface of the spacer 30, respectively. The first port 311 and the second port 312 have a predetermined distance in the first direction X.

[0167] The first wall 11 can be understood as the bottom wall of the shell, and the second wall 12 can be understood as the top wall of the shell.

[0168] As an example, the first wall 11 can be an end cap or a wall of the housing. The second wall 12 can be an end cap or a wall of the housing.

[0169] The fact that the electrode assembly 20 is supported by the first wall 11 means that the first wall 11 is used to provide support for the electrode assembly 20, wherein the support provided by the first wall 11 to the electrode assembly 20 is relative to the gravity acting on the electrode assembly 20.

[0170] The electrode can be either a positive electrode or a negative electrode.

[0171] The spacer 30 and the electrode assembly 20 are disposed along the second direction Y. As an example, the spacer 30 may be disposed on one side of the electrode assembly 20 along the second direction Y, or the spacer 30 may be disposed on opposite sides of the electrode assembly 20 along the second direction Y.

[0172] The spacer 30 can be integrally disposed with the electrode assembly 20 along the second direction Y, or only a portion thereof can be disposed with the electrode assembly 20 along the second direction Y.

[0173] The second direction, Y, is parallel to the thickness direction of the electrode. The thickness direction of the electrode can also be understood as the expansion direction of the electrode assembly 20.

[0174] Understandably, the electrode assembly 20 expands along the thickness direction of the electrode sheet during cycling. Since the spacer 30 can deform under external force, when the electrode assembly 20 expands along the thickness direction of the electrode sheet, it compresses the spacer 30. The spacer 30, through its own deformation, provides a certain amount of space to accommodate the expansion of the electrode assembly 20. Furthermore, the expansion of the electrode assembly 20 and its compression of the spacer 30 further drives the electrolyte within the channel 31 to flow out.

[0175] In some examples, the first direction X is perpendicular to the second direction Y.

[0176] As an example, the spacer 30 may be connected to the electrode assembly 20, wherein the spacer 30 may be detachably connected to the electrode assembly 20 or integrally disposed on the electrode assembly 20. The spacer 30 may be directly connected to the electrode assembly 20 or may be constrained to the electrode assembly 20 by other components.

[0177] As an example, the spacer 30 can also be connected to the housing 10, wherein the spacer 30 can be detachably connected to the housing 10 or integrally disposed on the housing 10. The spacer 30 can be directly connected to the housing 10 or constrained to the housing 10 by other components.

[0178] Optionally, the spacer 30 can be, but is not limited to, a sheet-like structure, a plate-like structure, a column-like structure, or a block-like structure, etc.

[0179] Optionally, the number of spacers 30 can be one or more. "More" refers to two or more.

[0180] Optionally, channel 31 can extend in a straight line or in a wavy shape.

[0181] Optionally, the number of channels 31 can be one or more, where more means two or more.

[0182] Optionally, the shape of the cross section of channel 31 perpendicular to its extension direction can be, but is not limited to, a circle, an ellipse, a rectangle, or a polygon.

[0183] The first port 311 and the second port 312 have a preset distance in the first direction X. This can be understood as one of the first port 311 and the second port 312 being relatively closer to the first wall 11, and the other of the first port 311 and the second port 312 being relatively closer to the second wall 12.

[0184] The first port 311 and the second port 312 are spaced apart in the first direction X so that the channel 31 can transport the electrolyte in the first direction X through the first port 311 and the second port 312.

[0185] As an example, the first port 311 is closer to the first wall 11 in the first direction X than the second port 312, and the second port 312 is closer to the second wall 12 in the first direction X than the first port 311.

[0186] In some examples, the first port 311 and the second port 312 may be located on opposite sides of the spacer 30 along the first direction X.

[0187] In other examples, the first port 311 and the second port 312 may also be located on opposite sides of the spacer 30 along the second direction Y, and the first port 311 and the second port 312 have a certain distance between them in the first direction X.

[0188] In some other examples, the first port 311 and the second port 312 may also be located on opposite sides of the spacer 30 along the third direction Z, with the first direction X, the second direction Y and the third direction Z being perpendicular to each other, and the first port 311 and the second port 312 having a certain distance between them in the first direction X.

[0189] Understandably, due to gravity, the electrolyte will accumulate towards the first wall 11, causing the electrolyte level to be lower than the area of ​​the electrode assembly 20 near the second wall 12. This results in some of the electrodes in that area of ​​the electrode assembly 20 not being fully immersed in the electrolyte.

[0190] The channel 31 of the above-described technical solution can form a capillary effect, allowing the electrolyte to be drawn into the channel 31. When the electrode assembly 20 expands and squeezes the spacer 30, the spacer 30 deforms to discharge the electrolyte located in the channel 31. Furthermore, the first port 311 and the second port 312 have a predetermined distance in the first direction X, enabling the channel 31 to transport the electrolyte in the first direction X through the first port 311 and the second port 312. This increases the wetting range of the electrolyte in the first direction X, reducing the impact of insufficient electrolyte wetting on the electrode assembly 20, thereby effectively improving the performance of the battery cell 7.

[0191] In some embodiments, the area S1 of the cross-section of channel 31 perpendicular to the extending direction satisfies the relationship: 0.2 mm 2 ≤S1≤180mm 2 .

[0192] As an example, the area S1 of the cross-section of channel 31 perpendicular to the extension direction can be, but is not limited to, 0.2 mm. 2 0.5mm 2 1mm 2 10mm 2 50mm 2 100mm 2 120mm 2 150mm 2 180mm 2 wait.

[0193] It is understandable that the area S1 of the cross-section of channel 31 perpendicular to the extension direction can affect the strength of the capillary effect and the fabrication difficulty of channel 31. The smaller the area S1 of the cross-section of channel 31 perpendicular to the extension direction, the better the capillary effect of channel 31, and the greater the fabrication difficulty of channel 31; conversely, the larger the area S1 of the cross-section of channel 31 perpendicular to the extension direction, the weaker the capillary effect of channel 31, and the easier the fabrication difficulty of channel 31.

[0194] The above technical solution sets the area S1 of the cross-section of channel 31 perpendicular to the extension direction within the above range, which can satisfy the capillary effect of channel 31 while reducing the fabrication difficulty of channel 31 to a certain extent.

[0195] For example, the area S1 of the cross-section of channel 31 perpendicular to the extension direction can be measured using a direct geometric measurement method. As an example, measuring tools such as vernier calipers, outside micrometers, or inside gauges can be used to measure the outer (or inner) diameter of the pipe, and then the cross-sectional area can be calculated using an area calculation formula. As another example, a cross-section of channel 31 can be obtained first (e.g., by cutting a sample or directly observing the pipe end), then drawn using a ruler, graduated ruler, or projected onto graph paper, and the area of ​​that cross-sectional shape can be calculated.

[0196] The area S1 of the cross-section of channel 31 perpendicular to the extension direction can also be measured using the image-based optical influence measurement method. As an example, the end face of channel 31 is photographed facing the camera to obtain a cross-sectional profile image. Then, image processing software is used to measure the profile to obtain the cross-sectional area. As another example, a laser scanner or structured light scanning device is used to scan the inside or end of the pipe to obtain three-dimensional point cloud data. A cross-sectional slice is then extracted from the data, and the cross-sectional area can be calculated using software.

[0197] In some embodiments, the area S1 satisfies the relationship: 0.8mm 2 ≤S1≤28mm 2 This can further improve the balance between channel 31's adsorption capacity for electrolyte and the difficulty of preparation.

[0198] As an example, the area S1 of the cross-section of channel 31 perpendicular to the extension direction can be, but is not limited to, 0.8 mm. 2 5mm 2 15mm 2 20mm 2 21mm 2 22mm 2 25mm 2 28mm 2 wait.

[0199] In some embodiments, the second port 312 is located on the end face of the spacer 30 along the first direction X near the second wall 12. This allows the electrolyte to more easily reach the portion of the electrode assembly 20 near the second wall 12, further improving the wetting effect of the electrolyte on the portion of the electrode assembly 20 near the second wall 12.

[0200] In some embodiments, the first port 311 is located on the side end face of the spacer 30 near the first wall 11 along the first direction X.

[0201] Understandably, under the influence of gravity, the electrolyte will preferentially accumulate towards the first wall 11. Due to this enrichment effect, the channel 31 can more easily obtain a sufficient and stable source of electrolyte in this region, thereby enhancing its ability to effectively absorb electrolyte.

[0202] Thus, the above technical solution can improve the smoothness of the electrolyte absorption process of channel 31, thereby significantly reducing the potential risk that channel 31 cannot obtain sufficient electrolyte.

[0203] In some embodiments, the channel 31 extends linearly along the first direction X. This allows for a uniform wetting range of the electrolyte along the first direction X, reducing the flow path and flow resistance, thereby improving the electrolyte delivery efficiency.

[0204] In some embodiments, the number of channels 31 is at least two, and the at least two channels 31 are spaced apart along a direction intersecting the extending direction of the channels 31. By further increasing the number of channels 31, the electrolyte delivery efficiency can be further improved, thereby helping to further improve the performance of the battery cell 7.

[0205] In some embodiments, the cross-section of the channel 31 perpendicular to its extension direction is circular. The channel 31 with a circular cross-section has structural symmetry and uniformity, and its hydrodynamic properties are superior to other shapes, such as rectangles or polygons.

[0206] The circular cross-section minimizes power loss during electrolyte flow, allowing for smooth and rapid electrolyte transport within channel 31. Furthermore, the circular cross-section design reduces the formation of sharp corners or dead zones, minimizing the risk of electrolyte stagnation or impaired flow, and further improving electrolyte transport efficiency.

[0207] In some embodiments, the electrode assembly 20 includes at least two electrodes, including a first electrode and a second electrode, the first electrode and the second electrode having opposite polarities. The second electrode covers the first electrode along the thickness direction, and the spacer 30 covers the second electrode along the second direction Y.

[0208] The second electrode covers the first electrode along the thickness direction of the electrode. This can be understood as the projection of the second electrode along the thickness direction of the electrode covering the projection of the first electrode along the thickness direction of the electrode.

[0209] The spacer 30 covers the second pole piece along the second direction Y, which can be understood as the projection of the spacer 30 along the second direction Y covering the projection of the second pole piece along the second direction Y.

[0210] For example, the first electrode is a positive electrode and the second electrode is a negative electrode. The second electrode covers the first electrode along the thickness direction of the electrode, which enables the active material of the negative electrode to have more ion insertion sites than the active material of its adjacent positive electrode can provide, thereby reducing the risk of lithium plating.

[0211] When the electrode assembly 20 expands, it presses against the spacer 30, and the spacer 30 exerts a reaction force on the electrode assembly 20. The spacer 30 covers the second electrode sheet along the second direction Y, which prevents the edge of the spacer 30 from pressing against the electrode sheet. This reduces the risk of stress concentration and damage to the electrode sheet caused by the pressure exerted by the edge of the spacer 30, thereby further improving the reliability of the battery cell 7.

[0212] In some embodiments, the elastic modulus of the spacer 30 is 0.1 MPa-10 MPa.

[0213] As an example, the elastic modulus of spacer 30 can be, but is not limited to, 0.1MPa, 0.5MPa, 1MPa, 2MPa, 5MPa, 8MPa, 10MPa, etc.

[0214] Understandably, the elastic modulus of the spacer 30 can affect its buffering effect on the expansion of the electrode assembly 20 and its structural stability. The smaller the elastic modulus of the spacer 30, the worse its buffering effect on the expansion of the electrode assembly 20, and the better its structural stability; conversely, the larger the elastic modulus of the spacer 30, the better its buffering effect on the expansion of the electrode assembly 20, and the worse its structural stability.

[0215] By setting the elastic modulus of the spacer 30 within the aforementioned range, the above-mentioned technical solution enables the spacer 30 to meet the requirements for buffering the expansion of the electrode assembly 20 while improving the structural stability of the spacer 30 to a certain extent.

[0216] For example, the elastic modulus of spacer 30 can be determined using a static mechanical testing method. As an example, a standard-sized material specimen is placed in a tensile testing machine, and an axial tensile force is applied under controlled strain or stress rates, while simultaneously measuring the axial stress and strain. The slope of the stress-strain curve, which exhibits a linear relationship in the elastic region, is the elastic modulus.

[0217] In some embodiments, the elastic modulus of the spacer 30 is 0.2 MPa-5 MPa. This can further improve the buffering effect of the spacer 30 on the expansion of the electrode assembly 20 and the balance between the structural stability of the spacer 30 and the overall performance.

[0218] As an example, the elastic modulus of spacer 30 can be, but is not limited to, 0.2MPa, 0.8MPa, 1MPa, 2MPa, 3MPa, 4MPa, 5MPa, etc.

[0219] As shown in Figures 5 and 6, in some embodiments, the spacer 30 is disposed between the electrode assembly 20 and the housing 10. Disposing the spacer 30 between the electrode assembly 20 and the housing 10 facilitates installation and directly reduces the stress on the housing 10 when the electrode assembly 20 expands, effectively reducing the risk of deformation of the housing 10.

[0220] Figure 12 is a front view of another battery cell 7 provided in some embodiments of this application, and Figure 13 is a cross-sectional view of Figure 12 along DD.

[0221] Referring again to Figures 12 and 13, in some embodiments, the number of electrode assemblies 20 is at least two, the at least two electrode assemblies 20 are arranged along the second direction Y, and the spacer 30 is disposed between two adjacent electrode assemblies 20.

[0222] When the spacer 30 is disposed between two adjacent electrode assemblies 20, the spacer 30 can both support and buffer the two adjacent electrode assemblies 20, and also separate the adjacent electrode assemblies 20, effectively preventing the adjacent electrode assemblies 20 from squeezing each other after expansion, thus improving the reliability of the battery cell 7. In addition, it can also reduce the impact on heat conduction between the electrode assembly 20 and the casing 10, which helps to improve the heat exchange efficiency of the battery cell 7.

[0223] In some embodiments, the spacer 30 is further provided with a through hole 32, which penetrates the spacer 30 along the second direction Y.

[0224] This allows the electrolyte to directly contact the electrode assembly 20 through the through-hole 32 to wet the electrode assembly 20, thereby increasing the area of ​​the direct contact interface between the electrolyte and the electrode assembly 20, which helps to further improve the performance of the battery cell 7.

[0225] As an example, the number of through holes 32 is at least two, and the at least two through holes 32 are spaced apart along the surface of the spacer 30 in the second direction Y. In other words, the at least two through holes 32 are spaced apart in a direction intersecting the second direction Y.

[0226] As an example, at least some of the through holes 32 may have different shapes and / or sizes to improve design flexibility.

[0227] As an example, all through holes 32 have the same shape and size, which reduces the difficulty of fabrication and reduces costs.

[0228] Optionally, the projection of the through hole 32 along the second direction Y can be, but is not limited to, a circle, an ellipse, a rectangle, a triangle, or a polygon.

[0229] In some embodiments, the through hole 32 and the channel 31 are spaced apart from each other. In other words, the through hole 32 and the channel 31 are not connected.

[0230] This not only reduces the impact of the introduction of through-hole 32 on the capillary effect of channel 31, but also reduces the overall fabrication difficulty of spacer 30, thus helping to reduce costs.

[0231] In some embodiments, the dimension d1 of the spacer 30 along the second direction Y satisfies the relationship: 1mm≤d1≤20mm.

[0232] For example, the dimension d1 of the spacer 30 along the second direction Y can also be understood as the thickness of the spacer 30.

[0233] As an example, the dimension d1 of the spacer 30 along the second direction Y can be, but is not limited to, 1mm, 3mm, 5mm, 7mm, 9mm, 10mm, 12mm, 14mm, 16mm, 18mm, 20mm, etc.

[0234] It is understandable that the dimension d1 of the spacer 30 along the second direction Y can affect the expansion absorption effect of the spacer 30 on the electrode assembly 20 and the energy density of the battery cell 7. The larger the dimension d1 of the spacer 30 along the second direction Y, the better the expansion absorption effect of the spacer 30 on the electrode assembly 20. At the same time, the spacer 30 occupies more internal space in the battery cell 7, and the lower the energy density of the battery cell 7. Conversely, the smaller the dimension d1 of the spacer 30 along the second direction Y, the worse the expansion absorption effect of the spacer 30 on the electrode assembly 20. At the same time, the spacer 30 occupies less internal space in the battery cell 7, and the higher the energy density of the battery cell 7.

[0235] The above technical solution, by setting the dimension d1 of the spacer 30 along the second direction Y within the above range, enables the spacer 30 to meet the requirements for the expansion absorption effect of the electrode assembly 20, while reducing the internal space occupied by the spacer 30 in the battery cell 7 and improving the energy density of the battery cell 7.

[0236] For example, the thickness of the spacer 30 can be measured using a contact mechanical measurement. As one example, the spacer 30 is placed flat, and its thickness is measured directly using a precision caliper or micrometer. As another example, the spacer 30 is measured directly using a thickness gauge, and the thickness value is then read.

[0237] In some embodiments, the dimension d1 satisfies the relationship: 2mm ≤ d1 ≤ 8mm. This can further improve the balance between the expansion absorption of the spacer 30 on the electrode assembly 20 and the energy density of the battery cell 7.

[0238] As an example, the dimension d1 of the spacer 30 along the second direction Y can be, but is not limited to, 2mm, 2.5mm, 3mm, 3.5mm, 4mm, 4.5mm, 5mm, 5.5mm, 6mm, 6.5mm, 7mm, 7.5mm, 8mm, etc.

[0239] In some embodiments, the electrode assembly 20 is a wound structure, and the electrode includes a straight portion and a bent portion. The bent portion is connected to both ends of the straight portion along the third direction Z, and the first direction X, the second direction Y and the third direction Z are perpendicular to each other.

[0240] For example, the electrode is wound into a wound structure, and the electrode has alternating straight portions and bent portions along the winding direction.

[0241] The electrode assembly 20 includes a flat region and two bent regions, which are respectively connected to the two ends of the flat region along the third direction Z. The flat region can also be understood as the large surface side of the electrode assembly 20.

[0242] As an example, each bending zone includes at least two bent portions stacked together, and the straight portion includes at least two straight portions stacked together.

[0243] The above technical solution provides a spacer 30 on the large side of the electrode assembly 20, which provides a relatively large space for the spacer 30, thereby reducing the difficulty of setting the spacer 30 and helping to improve the manufacturing complexity of the battery cell 7 and reduce costs.

[0244] Furthermore, it is understandable that the expansion of the electrode assembly 20 is greatest on its large-area side. By providing spacers 30 only on the large-area side of the electrode assembly 20, it is possible to absorb most of the expansion of the electrode assembly 20 while reducing the amount of spacers 30 used. This not only reduces the spacers 30's footprint on the internal space of the battery cell 7, increasing the energy density of the battery cell 7, but also reduces costs. Moreover, providing spacers 30 on the large-area side of the electrode assembly 20 allows for greater pressure exerted by the electrode assembly 20 on the spacers 30, further enhancing the effect of squeezing out the electrolyte and thus further increasing the electrolyte's wetting range.

[0245] In some embodiments, the electrode assembly 20 includes at least two electrodes, which are stacked along a second direction Y.

[0246] For example, the electrode assembly 20 is a stacked structure, with at least two electrodes including a positive electrode and a negative electrode.

[0247] As an example, multiple positive and negative electrodes can be set, and multiple positive and multiple negative electrodes can be stacked alternately.

[0248] As an example, multiple positive electrode plates can be provided, and negative electrode plates can be folded to form multiple stacked folded segments, with a positive electrode plate sandwiched between adjacent folded segments.

[0249] As an example, both the positive and negative electrode plates are folded to form multiple stacked folded segments.

[0250] In the above technical solution, the second direction Y is the expansion direction of the electrode assembly 20, and the spacer 30 and the electrode assembly 20 are arranged along the second direction Y, so that the spacer 30 can buffer the expansion of the electrode assembly 20, and under the pressure of the expansion of the electrode assembly 20 on the spacer 30, the electrolyte located in the channel 31 can be further driven to flow out.

[0251] In some embodiments, the electrode assembly 20 has a wound structure and is cylindrical, with the spacer 30 disposed around the electrode assembly 20. This allows the spacer 30 to better adapt to the structure of the cylindrical battery cell 7.

[0252] For example, the electrode sheet is wound into a wound structure so that the electrode assembly 20 is cylindrical. It should be noted that, due to certain process errors during the electrode winding process, the electrode assembly 20 mentioned in the embodiments of this application only needs to be approximately cylindrical.

[0253] As an example, the tab is wound multiple times along the winding direction. Optionally, the ends of the tab are bent by a flattening or smoothing process to form a multi-layered structure stacked in the axial direction of the electrode assembly 20. Optionally, the tab is annular.

[0254] In some embodiments, the spacer 30 is made of a liquid-absorbing material, which enables the spacer 30 to have good liquid absorption performance.

[0255] The spacer 30 absorbs liquid, allowing the electrolyte to indirectly wet the electrode assembly 20. This reduces the risk of insufficient wetting of the electrode assembly 20 due to changes in the electrolyte level caused by different operating conditions, thereby improving the overall performance and reliability of the battery.

[0256] Optionally, the absorbent material can be, but is not limited to, sponge, polyurethane foam, or silicone.

[0257] In some embodiments, the electrode includes a positive electrode, which includes a positive electrode active material, and the positive electrode active material includes at least one of sodium-containing transition metal oxides, Prussian blue compounds, and polyanionic compounds.

[0258] Optionally, the transition metal oxide includes Na x M yOne or more of O2 compounds and their modified compounds, wherein 0 < x ≤ 2.1, 0 < y ≤ 2.1, and M is selected from one or more of Ti, V, Cr, Fe, Co, Mn, Ni, Cu, Zn, Sr, Y, Zr, Nb, Mo, Cd, Sn, Sb, Te, Ba, Ta, W, Yb, La, and Ce; further optionally, M is selected from one or more of Ti, V, Cr, Fe, Co, Mn, Ni, Cu, and Zn.

[0259] For example, transition metal oxides include NaFeO2, NaTiO2, NaMnO2, Na2NiO2, and Na 2 / 3 [Ni 1 / 3 Mn 2 / 3 O2, Na 2 / 3 [Ni 1 / 3 Mn 1 / 3 Fe 1 / 3 O2, Na 2 / 3 [Cu 1 / 3 Mn 2 / 3 O2, Na 2 / 3 [Fe 1 / 2 Mn 1 / 2 O2, Na 2 / 3 [Co 2 / 3 Mn 1 / 3 O2, Na 7 / 9 [Cu 2 / 9 Fe 1 / 9 Mn 2 / 3 One or more of O2.

[0260] Alternatively, polyanionic compounds can be of various types, such as phosphates, pyrophosphates, mixed polyanionic compounds, sulfates, etc.

[0261] As an example, in addition to sodium ions, the cations of polyanionic compounds may also include cations of one or more elements from the following group: Ni, V, Co, Fe, Mn, Ti, Cr, Zn, and Cu.

[0262] As an example, the anions in polyanionic compounds include PO4. 3- P2O7 4- (PO4)2P2O7 10- (SO4)2 4- and (SO4)3 6- One or more of them.

[0263] As an example, the anions in polyanionic compounds also include F. - .

[0264] For example, the phosphate includes one or more of NaCoPO4, NaMnPO4, Na3V2(PO4)3, and NaCoPO4F.

[0265] For example, pyrophosphate includes one or more of Na2CoP2O7, Na2FeP2O7, and Na2MnP2O7.

[0266] For example, the mixed polyanionic compounds include one or more of Na4Co3(PO4)2P2O7, Na4Fe3(PO4)2P2O7, and Na4Mn3(PO4)2P2O7.

[0267] For example, the sulfate includes at least one of Na2Fe(SO4)2 and Na2Fe2(SO4)3.

[0268] The positive electrode sheet containing sodium-containing positive electrode active material has a high expansion rate. Therefore, by setting the spacer 30, the stress on the electrode assembly 20 during expansion can be effectively reduced, the deformation of the outer casing 10 can be reduced, the high expansion problem of the battery cell 7 during charging and discharging can be alleviated, and the service life of the battery cell 7 can be improved.

[0269] In some embodiments, the battery cell 7 is a metal battery cell.

[0270] For example, the battery cell 7 can be a lithium metal battery cell or a sodium metal battery cell.

[0271] The negative electrode current collector of a lithium metal battery cell or a sodium metal battery cell can be directly used as the negative electrode sheet. This type of battery cell can also be called a "negative electrode-free battery cell". During charging, lithium ions extracted from the positive electrode active material are deposited onto the negative electrode current collector to form lithium metal (i.e., the negative electrode active material is lithium metal), or sodium ions extracted from the positive electrode active material are deposited onto the negative electrode current collector to form sodium metal (i.e., the negative electrode active material is sodium metal).

[0272] Metal battery cells have a high expansion rate. Therefore, by setting the spacer 30, the stress on the electrode assembly 20 during expansion can be effectively reduced, the deformation of the casing 10 can be reduced, the problem of high expansion of the battery cell 7 during charging and discharging can be alleviated, and the service life of the battery cell 7 can be improved.

[0273] According to some embodiments of this application, this application also provides a battery device including a battery cell 7 of any of the above schemes.

[0274] According to some embodiments of this application, this application also provides an electrical device, including a battery cell 7 or a battery device of any of the above schemes, wherein the battery cell 7 or the battery device is used to store or provide electrical energy.

[0275] Unless otherwise specified, all embodiments and optional embodiments of this application can be combined to form new technical solutions. All technical features and optional technical features of this application can be combined to form new technical solutions.

[0276] To better understand the battery cell 7 provided in the embodiments of this application, based on the same inventive concept, embodiments of the battery cell 7 in practical applications are provided here for illustration.

[0277] This application provides a battery cell 7, which includes a housing 10, an electrode assembly 20, and a spacer 30. The housing 10 includes a first wall 11 and a second wall 12 disposed opposite to each other along a first direction X. The electrode assembly 20 is housed within the housing 10 and supported by the first wall 11. The electrode assembly 20 includes at least two electrodes, including a first electrode and a second electrode, with opposite polarities. The spacer 30 is housed within the housing 10 and disposed with the electrode assembly 20 along a second direction Y, which is parallel to the thickness direction of the electrode. The first direction X intersects the second direction Y. The second electrode covers the first electrode along its thickness direction, and the spacer 30 covers the second electrode along the second direction Y.

[0278] The spacer 30 is configured to elastically deform under external force. The spacer 30 has at least one channel 31 extending linearly along a first direction X. At both ends of the channel 31 along its extension direction, a first port 311 and a second port 312 are formed on the surface of the spacer 30. The second port 312 is located on the end face of the spacer 30 along the first direction X near the second wall 12, and the first port 311 is located on the end face of the spacer 30 along the first direction X near the first wall 11. The first port 311 and the second port 312 have a predetermined distance in the first direction X. The spacer 30 also has a through hole 32 penetrating through the spacer 30 along a second direction Y.

[0279] The channel 31 of the above-described technical solution can form a capillary effect, allowing the electrolyte to be drawn into the channel 31. When the electrode assembly 20 expands and squeezes the spacer 30, the spacer 30 deforms to discharge the electrolyte located in the channel 31. Furthermore, the first port 311 and the second port 312 have a predetermined distance in the first direction X, enabling the channel 31 to transport the electrolyte in the first direction X through the first port 311 and the second port 312. This increases the wetting range of the electrolyte in the first direction X, reducing the impact of insufficient electrolyte wetting on the electrode assembly 20, thereby effectively improving the performance of the battery cell 7.

[0280] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other.

[0281] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and not to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application, and they should all be covered within the scope of the claims and specification of this application. In particular, as long as there is no structural conflict, the various technical features mentioned in the embodiments can be combined in any way. This application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A single battery cell, comprising: The outer casing includes a first wall and a second wall disposed opposite to each other along a first direction; An electrode assembly, housed within the housing and supported by the first wall, the electrode assembly comprising electrode plates; A spacer is housed within the housing and disposed along a second direction parallel to the thickness direction of the electrode assembly. The first direction intersects the second direction. The spacer is configured to be elastically deformable under external force. The spacer has at least one channel, and the two ends of the channel along its extension direction form a first port and a second port on the surface of the spacer, respectively. The first port and the second port have a preset distance in the first direction.

2. The battery cell according to claim 1, wherein, The area S1 of the cross-section of the channel perpendicular to the extending direction satisfies the relationship: 0.2 mm. 2 ≤S1≤180mm 2 .

3. The battery cell according to claim 2, wherein, The area S1 satisfies the relationship: 0.8mm 2 ≤S1≤28mm 2 .

4. The battery cell according to any one of claims 1-3, wherein, The second port is located on the side end face of the spacer along the first direction near the second wall.

5. The battery cell according to claim 4, wherein, The first port is located on the side end face of the spacer along the first direction near the first wall.

6. The battery cell according to claim 5, wherein, The channel extends in a straight line along the first direction.

7. The battery cell according to any one of claims 1-6, wherein, The number of channels is at least two, and the at least two channels are spaced apart along a direction intersecting the extension direction.

8. The battery cell according to any one of claims 1-7, wherein, The cross-section of the channel perpendicular to its extension direction is circular.

9. The battery cell according to any one of claims 1-8, wherein, The electrode assembly includes at least two electrodes, each including a first electrode and a second electrode, the first electrode and the second electrode having opposite polarities; The second electrode covers the first electrode along the thickness direction, and the spacer covers the second electrode along the second direction.

10. The battery cell according to any one of claims 1-9, wherein, The elastic modulus of the spacer is 0.1 MPa-10 MPa.

11. The battery cell according to claim 10, wherein, The elastic modulus of the spacer is 0.2MPa-5MPa.

12. The battery cell according to any one of claims 1-11, wherein, The spacer is disposed between the electrode assembly and the housing.

13. The battery cell according to any one of claims 1-12, wherein, The number of electrode assemblies is at least two, and the at least two electrode assemblies are arranged along the second direction, with the spacer disposed between two adjacent electrode assemblies.

14. The battery cell according to any one of claims 1-13, wherein, The spacer is also provided with a through hole, which penetrates the spacer along the second direction.

15. The battery cell according to claim 14, wherein, The through holes and the channels are spaced apart from each other.

16. The battery cell according to any one of claims 1-15, wherein, The dimension d1 of the spacer along the second direction satisfies the relationship: 1mm≤d1≤20mm.

17. The battery cell according to claim 16, wherein, The dimension d1 satisfies the following relationship: 2mm≤d1≤8mm.

18. The battery cell according to any one of claims 1-17, wherein, The electrode assembly has a wound structure, and the electrode sheet includes a straight portion and a bent portion. The bent portion is connected to both ends of the straight portion along a third direction, and the first direction, the second direction, and the third direction are perpendicular to each other.

19. The battery cell according to any one of claims 1-17, wherein, The electrode assembly includes at least two electrodes, which are stacked along the second direction.

20. The battery cell according to any one of claims 1-17, wherein, The electrode assembly has a wound structure and is cylindrical, with the spacer arranged around the electrode assembly.

21. The battery cell according to any one of claims 1-20, wherein, The electrode includes a positive electrode, which includes a positive electrode active material, and the positive electrode active material includes at least one of sodium-containing transition metal oxides, Prussian blue compounds, and polyanionic compounds.

22. The battery cell according to any one of claims 1-21, wherein, The battery cell is a metal battery cell.

23. A battery device comprising at least two battery cells as described in any one of claims 1-22.

24. An electrical device comprising a battery cell as described in any one of claims 1-22 or a battery device as described in claim 23, wherein the battery cell or the battery device is used to store or provide electrical energy.

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