Battery monomer, battery device, electric equipment and energy storage device

Abstract

The utility model provides a battery monomer, a battery device, electric equipment and an energy storage device, and belongs to the technical field of batteries. The battery monomer comprises a shell, and an electrode assembly and a rigid ring which are accommodated in the shell; the electrode assembly is of a flat winding structure and comprises a straight part and two corner parts, and the two corner parts are arranged at the two ends of the straight part respectively; the rigid ring is sleeved outside the electrode assembly, the shape of the rigid ring is matched with that of the electrode assembly, and the rigid ring is in clearance fit with the electrode assembly. In the charge-discharge cycle process of the battery monomer, the volume of the electrode assembly is expanded, and the rigid ring can bind the whole circumference of the electrode assembly to limit the expansion amount of the electrode assembly, so that the structural deformation of the battery monomer in the life cycle is reduced, and the positive influence is further brought to the improvement of the working reliability of the battery monomer; and meanwhile, the energy density of the single battery is improved.

Description

Technical Field

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

[0002] Energy conservation and emission reduction are the key to the sustainable development of the automobile industry. Electric vehicles have become an important part of the sustainable development of the automobile industry due to their advantages in energy conservation and environmental protection. For electric vehicles, battery technology is an important factor in their development.

[0003] In the development of battery technology, in addition to improving battery performance, battery safety issues cannot be ignored. Therefore, how to optimize battery performance and ensure battery reliability has become a problem worthy of attention. Utility Model Content

[0004] The present application aims to solve at least one of the technical problems in the background technology. To this end, one purpose of the present application is to provide a battery cell, a battery device, an electrical device and an energy storage device, which can improve the working reliability of the battery cell and improve the energy density of the battery cell.

[0005] An embodiment of the first aspect of the present application provides a battery cell, including: a shell, an electrode assembly and a rigid ring; the electrode assembly is accommodated in the shell, the electrode assembly is a flat winding structure, the electrode assembly includes a straight part and two corner parts, the two corner parts are respectively arranged at both ends of the straight part; the rigid ring is accommodated in the shell and is sleeved on the outside of the electrode assembly, the shape of the rigid ring is adapted to the shape of the electrode assembly, and the rigid ring and the electrode assembly are gap-matched.

[0006] The battery cell of this embodiment is designed with a rigid ring on the outer sleeve of the electrode assembly, and the rigid ring and the electrode assembly are matched with each other in a gap, so that the rigid ring surrounds the entire circumference of the flat wound electrode assembly, and the gap between the rigid ring and the electrode assembly is small. In this way, the volume of the electrode assembly of the battery cell expands during the charge and discharge cycle, and the rigid ring can restrain the entire circumference of the electrode assembly to limit the expansion of the electrode assembly. This not only reduces the risk of fracture of the pole piece due to stretching, but also helps to reduce the structural deformation of the battery cell during its life cycle, which in turn has a positive impact on the improvement of the safety performance of the battery cell, thereby improving the working reliability of the battery cell.

[0007] In addition, in such a battery cell, compared with the method of reserving an expansion gap, the rigid ring in this embodiment occupies less space in the housing, which is conducive to improving the energy density of the battery cell.

[0008] In some embodiments, the inner circumference of the rigid ring is equal to the outer circumference of the electrode assembly, and the inner circumference of the rigid ring is in contact with the outer circumference of the electrode assembly.

[0009] In this embodiment, the entire circumference of the electrode assembly is in contact with the rigid ring. In a physical sense, the rigid ring has a better restraining effect on the electrode assembly, which can further reduce the expansion of the electrode assembly, thereby helping to improve the safety performance of the battery cell.

[0010] In some embodiments, the inner circumference of the rigid ring is greater than the outer circumference of the electrode assembly, and a gap is formed between the inner circumference of the rigid ring and the outer circumference of the electrode assembly.

[0011] The rigid ring is designed to form a gap between its inner circumference and the outer circumference of the electrode assembly, so that the rigid ring can at least limit the expansion of the electrode assembly to a certain extent, and the difficulty of assembling the electrode assembly and the rigid ring can be reduced.

[0012] In some embodiments, the gaps include two first gaps and two second gaps spaced apart along the thickness direction of the electrode assembly, the first gaps are arc-shaped, and the first gaps and the second gaps are alternately distributed along the circumference of the electrode assembly and connected end to end to form a closed ring.

[0013] The gap is designed as a closed ring so that the entire periphery of the electrode assembly does not fit the rigid ring, so that the gap can be used to absorb partial expansion and deformation of the electrode assembly.

[0014] In some embodiments, the width of the first gap is different from the width of the second gap. Under the premise that the rigid ring can limit the expansion of the electrode assembly, by designing the width of the first gap to be different from the width of the second gap, the requirements for the assembly accuracy between the electrode assembly and the rigid ring can be reduced, which is conducive to improving the assembly efficiency of the battery cell.

[0015] In some embodiments, the inner circumference L1 of the rigid ring and the outer circumference L2 of the electrode assembly satisfy: L2<L1≤L2×110%.

[0016] By designing L2<L1≤L2×110%, a gap is provided between the inner circumference of the rigid ring and the outer circumference of the electrode assembly, and the gap can be as small as possible. In this way, the electrode assembly and the rigid ring can be assembled more easily, and the physical restriction effect of the rigid ring on the electrode assembly can be effective, so as to limit the expansion of the electrode assembly.

[0017] In some embodiments, along the circumference of the rigid ring, the thickness of the rigid ring remains unchanged; the thickness t of the rigid ring satisfies: 10 μm≤t≤1000 μm.

[0018] In this embodiment, the thickness of the rigid ring is moderate, and the thickness of the rigid ring is not too thin, so as to be able to play a role of physical constraint on the electrode assembly. The thickness of the rigid ring is also not too thick, so that the rigid ring occupies as little space in the housing as possible, so as to improve the energy density of the battery cell.

[0019] In some embodiments, the elastic modulus E of the material of the rigid ring satisfies: E>1 GPa. This embodiment enables the material of the rigid ring to have excellent ability to resist elastic deformation, so that the rigid ring can reliably restrain the electrode assembly to effectively limit expansion of the electrode assembly.

[0020] In some embodiments, the rigid ring includes a plurality of sub-ring segments that are sequentially arranged and connected along the axial direction of the electrode assembly, and the centers of the plurality of sub-ring segments are collinearly arranged.

[0021] In this embodiment, the rigid ring is designed to consist of a plurality of sub-ring segments arranged in sequence along the axial direction of the electrode assembly. Compared with the assembly of an integrated rigid ring and an electrode assembly, the difficulty of assembling the sub-ring segments and the electrode assembly can be reduced, which is beneficial to improving the assembly efficiency of the battery cells.

[0022] In some embodiments, any two adjacent sub-annular segments among the plurality of sub-annular segments are connected by at least one of adhesive connection, snap connection and welding connection.

[0023] Thanks to the fact that any two adjacent sub-ring segments are connected by at least one of bonding, clamping and welding, the structural stability and reliability of the rigid ring assembled from a plurality of sub-ring segments can be improved.

[0024] In some embodiments, the battery cell further includes a tape layer, the tape layer extends along the axial direction of the electrode assembly, and two ends of the tape layer are respectively bonded and connected to outer surfaces of two sub-annular segments of the plurality of sub-annular segments.

[0025] The adhesive force of the tape layer is good, so that the connection of the two sub-ring segments connected by the tape layer is reliable. Moreover, compared with the welding method, the two sub-ring segments connected by the tape layer can be conveniently connected, and the risk of welding slag splashing onto the electrode assembly and causing damage to the electrode assembly can be reduced.

[0026] In some embodiments, the shell is in the shape of a cuboid; the rigid ring has two arc segments, the two arc segments face two corner portions respectively, and the arc segments have corner areas facing the vertical edges of the shell; the tape layer is arranged on the surface of the arc segments and located in the corner areas.

[0027] This embodiment allows a larger distance between the tape layer and the outer shell, which can help reduce the possibility of contact and friction between the tape layer and the outer shell, and further reduce the risk of damage and warping of the tape layer due to friction.

[0028] In some embodiments, a covering layer is further provided on the outside of the rigid ring, and the covering layer covers the outer circumferential surface of the rigid ring; the covering layer is a single-layer structure, and the covering layer is an insulating layer, or the covering layer includes a plurality of sub-layers stacked in sequence along the thickness direction of the rigid ring, and at least one of the plurality of sub-layers is an insulating layer.

[0029] In this embodiment, at least an insulating layer is provided on the outer side of the rigid ring to insulate and isolate the rigid ring from the outer shell, thereby reducing the risk of short circuit caused by the conductive connection of the electrode assembly to the outer shell through the rigid ring.

[0030] In some embodiments, an outer ring of the electrode assembly is provided with an isolation layer, and the isolation layer is used to insulate and isolate the electrode assembly and the rigid ring.

[0031] In some embodiments, a supporting sheet is integrally connected to the bottom end of the rigid ring, and the supporting sheet is connected to the bottom end of the rigid ring in a turning manner and covers the bottom opening of the rigid ring.

[0032] By designing the support sheet, the support sheet can be used to support the electrode assembly. Moreover, since the support sheet is integrally connected to the bottom end of the rigid ring, the process of separately manufacturing the support sheet and separately installing the support sheet into the housing can be omitted.

[0033] In some embodiments, the rigid ring includes two arc segments and two straight segments spaced apart along the thickness direction of the electrode assembly, the arc segments and the straight segments are alternately distributed along the circumference of the electrode assembly and are connected end to end; a first sheet and a second sheet are respectively extended from the bottom ends of the two straight segments, and the first sheet and the second sheet are folded in a direction close to each other relative to the rigid ring and spliced ​​to form a supporting sheet.

[0034] Compared with the supporting sheet being an integral type, without changing the size of the supporting sheet, the sizes of the first sheet and the second sheet can be smaller, and the space required for folding the first sheet and the second sheet is smaller.

[0035] An embodiment of a second aspect of the present application provides a battery device, which includes the battery cell in the above embodiment.

[0036] An embodiment of the third aspect of the present application provides an electrical device, which includes the battery device in the above embodiment, and the battery device is used to provide electrical energy.

[0037] An embodiment of the fourth aspect of the present application provides an energy storage device, which includes the battery device in the above embodiment.

[0038] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In the accompanying drawings, unless otherwise specified, the same reference numerals throughout the multiple drawings represent the same or similar parts or elements. These drawings are not necessarily drawn to scale. It should be understood that these drawings only depict some embodiments disclosed in the present application and should not be regarded as limiting the scope of the present application.

[0040] Figure 1 A schematic diagram of the structure of a vehicle according to some embodiments of the present application;

[0041] Figure 2 A schematic diagram of the exploded structure of a battery device according to some embodiments of the present application;

[0042] Figure 3 An exploded schematic diagram of a battery cell according to some embodiments of the present application;

[0043] Figure 4 for Figure 3 A schematic cross-sectional view of a battery cell shown in ;

[0044] Figure 5 for Figure 3 Schematic diagram of the cooperation between the electrode assembly and the rigid ring of the battery cell shown in ;

[0045] Figure 6 for Figure 5 A schematic diagram of the structure of the electrode assembly and the rigid ring shown in ;

[0046] Figure 7 A schematic diagram of the structure of the electrode assembly and the rigid ring in the battery cell of other embodiments of the present application;

[0047] Figure 8 Schematic diagram of the cooperation between the rigid ring and the electrode assembly in some other embodiments of the present application;

[0048] Fig. 9 for Figure 8 An exploded schematic diagram of the rigid ring and electrode assembly shown in ;

[0049] Fig.10 This is a schematic structural diagram of a rigid ring in some other embodiments of the present application when the first sheet and the second sheet are in an unfolded state;

[0050] Fig.11 This is a schematic structural diagram of a rigid ring in some other embodiments of the present application when the first sheet and the second sheet are in a folded state;

[0051] Fig.12 A schematic diagram of a manufacturing process of a rigid ring connected with an integral support sheet in some embodiments of the present application;

[0052] Fig.13This is a schematic diagram of a manufacturing process of a rigid ring connected with a first sheet and a second sheet in some embodiments of the present application.

[0053] Description of reference numerals:

[0054] Vehicles 1000;

[0055] Battery device 100, controller 200, motor 300;

[0056] Battery cell assembly 10, battery cell 11, shell 111, shell 1111, end cover 1112, electrode assembly 112, straight portion 1121, corner portion 1122, rigid ring 113, sub-ring segment 1131, straight segment 1132, arc segment 1133, gap 114, first gap 1141, second gap 1142, tape layer 115, coating layer 116, isolation layer 117, supporting sheet 118, first sheet 1181, second sheet 1182, through hole 1183;

[0057] Box 20, first box 21, second box 22;

[0058] Rectangular metal foil 30 , flat sheet 31 , rectangular sheet 32 ​​. DETAILED DESCRIPTION

[0059] The following embodiments of the technical solution of the present application are described in detail in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present application, and are therefore only used as examples, and cannot be used to limit the scope of protection of the present application.

[0060] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" in the specification and claims of this application and the above-mentioned figure descriptions and any variations thereof are intended to cover non-exclusive inclusions.

[0061] In the description of the embodiments of the present application, the technical terms "first", "second", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present application, the meaning of "multiple" is more than two, unless otherwise clearly and specifically defined.

[0062] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0063] In the description of the embodiments of the present application, the term "and / or" is only a description of the association relationship of the associated objects, indicating that there may be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0064] In the description of the embodiments of the present application, the term "multiple" refers to more than two (including two). Similarly, "multiple groups" refers to more than two groups (including two groups), and "multiple pieces" refers to more than two pieces (including two pieces).

[0065] In the description of the embodiments of the present application, the technical terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, which are only for the convenience of describing the embodiments of the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the embodiments of the present application.

[0066] In the description of the embodiments of the present application, unless otherwise clearly specified and limited, technical terms such as "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the internal connection of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0067] At present, from the perspective of market development, the application of power batteries is becoming more and more extensive. Power batteries are not only used in energy storage power systems such as hydropower, thermal power, wind power and solar power stations, but also widely used in electric vehicles such as electric bicycles, electric motorcycles, electric cars, as well as military equipment and aerospace and other fields. With the continuous expansion of the application field of power batteries, the market demand is also constantly expanding.

[0068] As the positive and negative active materials embed or extract ions during the charge and discharge cycle of the battery device, the structure of the positive and negative plates will expand, resulting in the expansion of the thickness of the electrode assembly and the deformation of the shell that contains the electrode assembly, which will cause the battery cell to generate expansion force. The expansion of the pole piece has an adverse effect on the performance and service life of the battery cell. For example, the internal pressure of the battery cell increases, and the performance and service life of the battery cell will decline; the structural frame of the battery module composed of multiple battery cells is easily damaged.

[0069] In order to alleviate the problem of expansion force, some related technologies reserve expansion gaps for electrode assemblies in design. Specifically, during the winding process of the wound electrode assembly, an insulating sheet is placed between the pole piece and the diaphragm, and the insulating sheet is pulled out after winding, so that an expansion gap is reserved between the pole piece and the diaphragm. The expansion gap is used to absorb the expansion deformation generated during the cycle. However, although the reserved expansion gap can absorb the expansion deformation, it will cause a great sacrifice in the energy density of the battery cell, and it is easy to take out the pole piece or diaphragm when the insulating sheet is pulled out, affecting the safety performance of the battery cell.

[0070] In addition, it is worth pointing out that compared with battery cells with cylindrical wound electrode assemblies, battery cells with flat wound electrode assemblies have more serious problems caused by expansion. This is because the shape of the outer shell of the cylindrical battery cell is similar to that of the wound electrode assembly, and the outer shell has a physical restriction effect on the electrode assembly, and the electrode assembly is restricted by the outer shell all around, while the flat wound electrode assembly is usually contained in a rectangular outer shell, and the rectangular outer shell has little physical restriction effect on the corner part of the flat wound electrode assembly. The expansion rate of the flat wound electrode assembly along its own circumference is uneven, resulting in uneven expansion force of the battery cell, and the corner part expands and involves the straight part of the electrode assembly, resulting in a high stretch rate of the pole piece and easy breakage.

[0071] Based on the above considerations, for a battery cell having a flat wound electrode assembly, a rigid ring is sleeved outside the electrode assembly, and the shape of the rigid ring is set to match the shape of the flat wound electrode assembly, and the rigid ring and the electrode assembly are gap-matched.

[0072] In such a battery cell, since the rigid ring and the electrode assembly are gap-fitted, when the electrode assembly swells during the charge and discharge cycle of the battery cell in use, the rigid ring can restrain the electrode assembly to limit the expansion of the electrode assembly. By reducing the expansion of the electrode assembly through physical constraint, the expansion of the battery cell can be reduced, thereby improving the safety performance and operating reliability of the battery cell.

[0073] Thanks to the shape of the rigid ring being compatible with the shape of the flat wound electrode assembly, the entire circumference of the electrode assembly can be subject to the restraining force exerted by the rigid ring, so that the corner part of the flat wound electrode assembly can also be restricted, which can effectively reduce the possibility of excessive expansion and protrusion of the corner part, resulting in high stretching rate of the electrode and causing breakage.

[0074] The technical solutions described in the embodiments of the present application are applicable to battery cells, battery devices including battery cells, electrical equipment using the battery devices, and energy storage devices.

[0075] In the embodiment of the present application, the energy storage device using a battery device as a power source includes one or more battery clusters to increase the voltage and capacity of the energy storage device. The battery cluster may include multiple battery devices, and the multiple battery devices are connected in series through a busbar to increase the voltage of the energy storage device. When the energy storage device includes multiple battery clusters, the multiple battery clusters are connected in parallel to increase the capacity of the energy storage device.

[0076] The energy storage device can be used in energy storage power stations, wind power generation systems, solar power generation systems, mobile power systems or temporary power supply systems, etc. The energy storage device can store electrical energy as needed and output electrical energy at an appropriate time. For example, the energy storage device can store electrical energy during low electricity consumption, and provide electrical energy to relevant users or electrical equipment during peak electricity consumption. The energy storage system provided in the embodiment of the present application can be any power system that requires the use of an energy storage device. As an example, the energy storage device is an energy storage container or an energy storage cabinet.

[0077] In the embodiments of the present application, the electrical equipment using the battery device as the power source may be, but is not limited to, mobile phones, tablets, laptop computers, electric toys, electric tools, battery cars, electric cars, ships, spacecraft, etc. Among them, the electric toys may include fixed or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc., and the spacecraft may include airplanes, rockets, space shuttles, and spacecraft, etc.

[0078] It should be understood that the technical solutions described in the embodiments of the present application are not limited to the energy storage devices and electrical equipment described above, but can also be applied to all battery devices including a box and electrical equipment using the battery devices. However, for the sake of simplicity of description, the following embodiments are described using the electrical equipment as a vehicle as an example.

[0079] Please refer to Figure 1 , Figure 1A schematic diagram of the structure of a vehicle 1000 provided for some embodiments of the present application. The vehicle 1000 may be a fuel vehicle, a gas vehicle or a new energy vehicle, and the new energy vehicle may be a pure electric vehicle, a hybrid vehicle or an extended-range vehicle, etc. A battery device 100 is provided inside the vehicle 1000, and the battery device 100 may be provided at the bottom, head or tail of the vehicle 1000. The battery device 100 may be used to power the vehicle 1000, for example, the battery device 100 may be used as an operating power source for the vehicle 1000. The vehicle 1000 may also include a controller 200 and a motor 300, and the controller 200 is used to control the battery device 100 to power the motor 300, for example, for starting, navigating and driving the vehicle 1000.

[0080] In some embodiments of the present application, the battery device 100 can not only serve as an operating power source for the vehicle 1000, but also serve 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.

[0081] Figure 2 FIG. 1 is a schematic diagram showing the structure of a battery device 100 according to an embodiment of the present application. Figure 2 As shown, the battery apparatus 100 (Battery Apparatus) mentioned in the embodiment of the present application may include one or more battery cell assemblies 10 for providing voltage and capacity. The battery cell assembly 10 (Battery Cell Assembly) may include a plurality of battery cells 11, and the plurality of battery cells 11 are connected in series, in parallel or in mixed connection through a busbar component.

[0082] In some embodiments, a battery cell assembly 10 (Battery Cell Assembly) is generally formed by arranging a plurality of battery cells 11 .

[0083] As an example, the battery cell assembly 10 may be a battery module (Battery Module), and the battery module is formed by arranging and fixing a plurality of battery cells 11 to form an independent module. As an example, the battery module may be formed by bundling a plurality of battery cells 11 by a cable tie.

[0084] In some embodiments, Figure 2As shown, the battery device 100 may be a battery pack, which includes a box 20 and one or more battery cell assemblies 10, and the battery cell assemblies 10 are contained in the box 20. The box 20 may be a simple three-dimensional structure such as a single cuboid, cylinder, or sphere, or a complex three-dimensional structure composed of simple three-dimensional structures such as cuboids, cylinders, or spheres. The material of the box 20 may be an alloy material such as aluminum alloy, iron alloy, or a polymer material such as polycarbonate, polyisocyanurate foam plastic, or a composite material such as glass fiber and epoxy resin.

[0085] As an example, the battery cell assembly 10 may be a battery module, and the battery cell assembly 10 may be accommodated in the box body 20 by fixing the battery module in the box body 20 .

[0086] As an example, the battery cell assembly 10 may also be accommodated in the case 20 by directly fixing the plurality of battery cells 11 to the case 20 .

[0087] As an example, the box 20 may include a first box 21 and a second box 22. The first box 21 and the second box 22 are buckled together to form a closed space inside the box 20 to accommodate the battery cell assembly 10. The closed space here means covering or closing, which may be unsealed or sealed to prevent liquid or other foreign matter from affecting the charging or discharging of the battery cell 11. The first box 21 may be a top cover or a bottom plate.

[0088] As an example, the box body 20 may include a top cover, a frame, and a bottom plate. The top cover and the bottom plate are respectively connected to the frame, so that a closed space is formed inside the box body 20 to accommodate the battery cell assembly 10.

[0089] In some embodiments, the box 20 can be used as a part of the chassis structure of the vehicle. For example, part of the box 20 can become at least a part of the floor of the vehicle, or part of the box 20 can become at least a part of the cross beam and longitudinal beam of the vehicle.

[0090] The battery cell 11 provided in the embodiment of the present application may be a secondary battery. A secondary battery refers to a battery cell 11 that can be continuously used by activating active materials by charging after the battery cell 11 is discharged.

[0091] The battery cell 11 can be a lithium ion battery, a sodium ion battery, a sodium lithium ion battery, a lithium metal battery, a sodium metal battery, a lithium sulfur battery, a magnesium ion battery, a nickel hydrogen battery, a nickel cadmium battery, a lead storage battery, etc., which is not limited in the embodiments of the present application.

[0092] like Figure 3As shown, the battery cell 11 provided in the embodiment of the present application includes a housing 111, an electrode assembly 112 and an electrolyte (not shown in the figure), the electrode assembly 112 is a component in the battery cell 11 where an electrochemical reaction occurs, and the electrode assembly 112 and the electrolyte are contained in the housing 111. As an example, the electrolyte may be liquid, gel or solid.

[0093] As an example, the battery cell 11 can be a cylindrical battery cell, a prismatic battery cell, or a battery cell 11 of other shapes. The prismatic battery cell includes a square shell battery cell, a blade-shaped battery cell, and a polygonal battery cell. The polygonal battery cell is, for example, a hexagonal battery cell, etc. There is no particular limitation in this embodiment.

[0094] As an example, the housing 111 may be a steel shell, an aluminum shell, a plastic shell (such as polypropylene), a composite metal shell (such as a copper-aluminum composite shell 1111) or an aluminum-plastic film, etc. In some embodiments, the housing 111 may be a sealed structure or a non-sealed structure. As an example, when the housing 111 is a non-sealed structure, the housing 111 plays a role in protecting the electrode assembly 112, and a sealing bag is also included between the housing 111 and the electrode assembly 112, and the sealing bag is used to encapsulate the electrode assembly 112 and the electrolyte. Specifically, the sealing bag may be a bag-shaped insulating member or an aluminum-plastic film. When the housing 111 is a sealed structure, it is used to encapsulate components such as the electrode assembly 112 and the electrolyte.

[0095] In some embodiments, Figure 3 As shown, the housing 111 may include an end cap 1112 and a shell 1111, the shell 1111 is provided with an opening, the electrode assembly 112 is loaded into the shell 1111 through the opening, and the end cap 1112 is covered on the opening. The shell 1111 may be provided with one or more openings. One or more end caps 1112 may also be provided.

[0096] Please continue reading Figure 3 The electrode assembly 112 is a flat winding structure, and the electrode assembly 112 includes a straight portion 1121 and two corner portions 1122, and the two corner portions 1122 are respectively arranged at both ends of the straight portion 1121. Figures 3 to 5 As shown, the battery cell 11 provided in the embodiment of the present application also includes a rigid ring 113, which is accommodated in the outer shell 111 and sleeved outside the electrode assembly 112. The shape of the rigid ring 113 is adapted to the shape of the electrode assembly 112, and the rigid ring 113 and the electrode assembly 112 are gap-matched.

[0097] The electrode assembly 112 is a winding structure formed by stacking and winding a positive electrode sheet, a separator, a negative electrode sheet and a separator in sequence, and the electrode assembly 112 is flat. The straight portion 1121 and the corner portion 1122 both include a stacked positive electrode sheet, a separator, a negative electrode sheet and a separator.

[0098] The rigidity (also known as stiffness) of the rigid ring 113 refers to the property of having a small deformation ability under the action of external force. In other words, the rigid ring 113 has the ability to resist elastic deformation when subjected to force. The shape of the rigid ring 113 is adapted to the shape of the electrode assembly 112, which means that the shape of the rigid ring 113 is the same or nearly the same as the shape of the flat electrode assembly 112. Accordingly, the rigid ring 113 is as follows: Figure 3 Specifically, the racetrack-shaped rigid ring 113 includes two arc segments 1133 and two straight segments 1132 spaced apart along the thickness direction of the electrode assembly 112. Along the circumference of the electrode assembly 112, the arc segments 1133 and the straight segments 1132 are alternately distributed and connected end to end, and the two arc segments 1133 are respectively opposite to the two corner portions 1122. In the various drawings of the embodiments of the present application, the directions of the X-axis, the Y-axis, and the Z-axis represent the length direction, the thickness direction, and the axial direction of the flat electrode assembly 112, respectively.

[0099] The number of electrode assemblies 112 is equal to the number of rigid rings 113, and each rigid ring 113 is correspondingly sleeved outside an electrode assembly 112 to limit the expansion of the corresponding electrode assembly 112. For example, there are only one electrode assembly 112 and one rigid ring 113. Or, Figure 3 and Figure 4 As shown, there are two electrode assemblies 112 and two rigid rings 113, and the two electrode assemblies 112 are stacked along their thickness direction. Alternatively, there are three or more electrode assemblies 112 and three rigid rings 113.

[0100] The above-mentioned clearance fit means that there is a gap (including a minimum gap equal to zero) between the rigid ring 113 and the electrode assembly 112 that are combined and matched together. In other words, the dimensional tolerance zone of the inner circumference of the rigid ring 113 is above the dimensional tolerance zone of the outer circumference of the electrode assembly 112.

[0101] The battery cell 11 of this embodiment is designed to have a rigid ring 113 on the outer sleeve of the electrode assembly 112, and the rigid ring 113 and the electrode assembly 112 are gap-matched, so that the rigid ring 113 surrounds the entire circumference of the flat wound electrode assembly 112, and the gap between the rigid ring 113 and the electrode assembly 112 is small. In this way, during the charge and discharge cycle of the battery cell 11, the rigid ring 113 can restrain the entire circumference of the electrode assembly 112 to limit the continued expansion of the electrode assembly 112, which not only reduces the risk of fracture of the pole piece due to stretching, but also helps to reduce the expansion of the battery cell 11, and reduce the structural deformation of the battery cell 11 during its life cycle, which in turn has a positive impact on the improvement of the safety performance of the battery cell 11, thereby helping to improve the working reliability of the battery cell 11.

[0102] Since the shape of the rigid ring 113 matches the shape of the flat wound electrode assembly 112, the entire circumference of the flat electrode assembly 112 can be constrained by the rigid ring 113, so as to improve the consistency of the expansion rate of the flat wound electrode assembly 112 along its own circumference, reduce the risk of excessive expansion of the electrode assembly 112 at local positions and involving other positions, resulting in electrode breakage, and promote uniform expansion force of the battery cell 11.

[0103] In addition, compared with the method of placing an insulating sheet between the pole piece and the diaphragm to reserve an expansion gap in the related art, the rigid ring 113 is used in this embodiment to physically restrict the entire circumference of the electrode assembly 112, and the space occupied by the rigid ring 113 in the housing 111 is smaller than the space occupied by multiple insulating sheets in the housing 111, which is conducive to improving the energy density of the battery cell 11. Moreover, it can also eliminate the problem of affecting the safety performance of the battery cell 11 due to the pole piece or the diaphragm being taken out due to the extraction of the insulating sheet.

[0104] It is understandable that there are various ways to implement the clearance fit between the rigid ring 113 and the electrode assembly 112 , and several implementations are described below.

[0105] According to some embodiments of the present application, the inner circumference of the rigid ring 113 may be equal to the outer circumference of the electrode assembly 112 , and the inner circumference of the rigid ring 113 fits with the outer circumference of the electrode assembly 112 .

[0106] In this example, the orthographic projection of the outer contour of the electrode assembly 112 on the XY plane coincides with the orthographic projection of the inner circumference of the rigid ring 113 on the XY plane.

[0107] In this embodiment, the entire circumference of the electrode assembly 112 is in contact with the rigid ring 113 . In a physical sense, the rigid ring 113 has a better restraining effect on the electrode assembly 112 , which can further reduce the expansion of the electrode assembly 112 , thereby improving the safety performance of the battery cell 11 .

[0108] According to some embodiments of this application, please continue to refer to Figure 4 and Figure 5 The inner circumference of the rigid ring 113 may be greater than the outer circumference of the electrode assembly 112 , and a gap 114 is formed between the inner circumference of the rigid ring 113 and the outer circumference of the electrode assembly 112 .

[0109] That is to say, in this example, the entire outer circumference of the electrode assembly 112 is not completely in contact with the inner circumference of the rigid ring 113 , and the gap between at least part of the inner circumference of the rigid ring 113 and the outer circumference of the electrode assembly 112 is greater than zero, forming a gap 114 .

[0110] The rigid ring 113 is designed to form a gap 114 between its inner circumference and the outer circumference of the electrode assembly 112, so that the rigid ring 113 can at least limit the expansion of the electrode assembly 112 to a certain extent. This can reduce the difficulty of assembling the electrode assembly 112 and the rigid ring 113, making it easier for the electrode assembly 112 to be inserted into the rigid ring 113 or for the rigid ring 113 to be more easily fitted onto the outside of the electrode assembly 112, which can help improve the assembly efficiency of the battery cell 11.

[0111] It is understood that the gap 114 formed between the inner circumference of the rigid ring 113 and the outer circumference of the electrode assembly 112 should be understood in a broad sense, for example, it can be understood that the entire outer circumference of the electrode assembly 112 is not in contact with the rigid ring 113. Alternatively, part of the outer circumference of the electrode assembly 112 is in contact with the rigid ring 113.

[0112] According to some embodiments of this application, please combine Figure 5 and Figure 6 The gap 114 may include two first gaps 1141 and two second gaps 1142 spaced apart along the thickness direction of the electrode assembly 112, the first gap 1141 is arc-shaped, and the first gaps 1141 and the second gaps 1142 are alternately distributed along the circumference of the electrode assembly 112 and connected end to end to form a closed ring.

[0113] Specifically, the straight portion 1121 has a first surface and a second surface opposite to each other along its own thickness direction, a second gap 1142 is formed between one of the two straight sections 1132 and the first surface of the straight portion 1121, a second gap 1142 is formed between the other of the two straight sections 1132 and the second surface of the straight portion 1121, a first gap 1141 is formed between one of the two arc sections 1133 and one of the two corner sections 1122, and a first gap 1141 is formed between the other of the two arc sections 1133 and the other of the two corner sections 1122.

[0114] In this embodiment, the gap 114 is designed as a closed ring, so that the entire periphery of the electrode assembly 112 is not in contact with the rigid ring 113. In this way, the gap 114 can be used to absorb part of the expansion and deformation of the electrode assembly 112. When the electrode assembly 112 swells to the point where its periphery contacts the rigid ring 113, the rigid ring 113 physically restricts the electrode assembly 112 to limit the further expansion of the electrode assembly 112. As a result, the electrode assembly 112 and the rigid ring 113 can be assembled more easily while the rigid ring 113 can still restrict the expansion of the electrode assembly 112, which can help improve the assembly efficiency of the battery cell 11.

[0115] In some embodiments, the width of the gap 114 may remain unchanged along the circumference of the electrode assembly 112. In other words, the width of the gap 114 may be equal everywhere, that is, the width w1 of the first gap 1141 is equal to the width w2 of the second gap 1142. In the charge and discharge cycle of the battery cell 11 of this example, the expansion rate of the electrode assembly 112 along its own circumference is consistent, that is, the outer periphery of the electrode assembly 112 expands outward uniformly, and the width of the gap between the outer circumference of the electrode assembly 112 and the inner circumference of the rigid ring 113 gradually decreases until the gap becomes zero, and there is no gap 114 between the outer circumference of the electrode assembly 112 and the inner circumference of the rigid ring 113, and the rigid ring 113 restrains the electrode assembly 112.

[0116] By designing the width of the gap 114 to be equal everywhere, the gap 114 can absorb the same amount of expansion and deformation along the circumference of the electrode assembly 112, so as to make the rigid ring 113 have a uniform restraining force on the expanded and deformed electrode assembly 112 throughout the entire circumference. In other words, since the width of the gap 114 is equal everywhere, the expanded electrode assembly 112 exerts an expansion force on the rigid ring 113 throughout the entire circumference. Conversely, along the entire circumference of the electrode assembly 112, the rigid ring 113 generates a restraining force to apply to the electrode assembly 112, uniformly limiting the expansion of the electrode assembly 112 throughout the entire circumference.

[0117] According to some embodiments of the present application, the width w1 of the first gap 1141 and the width w2 of the second gap 1142 may also be different.

[0118] Wherein, w1 may be smaller than w2, and when the electrode assembly 112 expands until the two corner portions 1122 are respectively in contact with the two arc segments 1133, the rigid ring 113 physically restricts the electrode assembly 112. Alternatively, w1 may be larger than w2.

[0119] Compared with the implementation scheme in which the width of the gap 114 is equal everywhere, this embodiment is designed in such a way that, under the premise that the rigid ring 113 can limit the expansion of the electrode assembly 112, since w1 and w2 are not equal, the requirements for assembly accuracy between the electrode assembly 112 and the rigid ring 113 can be reduced, which is beneficial to improving the assembly efficiency of the battery cell 11.

[0120] Based on the embodiment in which a gap 114 is formed between the inner circumference of the rigid ring 113 and the outer circumference of the electrode assembly 112, as an alternative example, the gap 114 may only include the above-mentioned two first gaps 1141, that is, the two straight sections 1132 are respectively attached to the first surface and the second surface, and the two arc sections 1133 are opposite to the two corner portions 1122 one by one and do not contact. In this example, when the rigid ring 113 is assembled with the electrode assembly 112, the attachment relationship between the two straight sections 1132 and the first surface and the second surface can be used to play an assembly positioning role, which can help improve the assembly efficiency of the battery cell 11. Specifically, when the rigid ring 113 is mounted outside the electrode assembly 112, the first surface and the second surface can be used as positioning references.

[0121] As an alternative example, the gap 114 may only include the two second gaps 1142, that is, the two straight sections 1132 are opposite to the first surface and the second surface one by one and do not contact each other, and the two arc sections 1133 are fitted with the two corner portions 1122 one by one. In this example, when the rigid ring 113 is assembled with the electrode assembly 112, the fitting relationship between the two arc sections 1133 and the two corner portions 1122 can be used to play an assembly positioning role, which can help improve the assembly efficiency of the battery cell 11.

[0122] According to some embodiments of the present application, the inner circumference L1 of the rigid ring 113 and the outer circumference L2 of the electrode assembly 112 may be designed to satisfy: L2<L1≤L2×110%.

[0123] When the above-mentioned gap 114 is implemented in any of the following ways, including two first gaps 1141, two second gaps 1142, and two first gaps 1141 and two second gaps 1142, the inner circumference L1 of the rigid ring 113 may not exceed 1.1 times the outer contour circumference L2 of the electrode assembly 112, so that the widths of the first gap 1141 and the second gap 1142 are relatively small, and the rigid ring 113 and the electrode assembly 112 are clearance-fitted.

[0124] By designing L2<L1≤L2×110%, a gap 114 is provided between the inner circumference of the rigid ring 113 and the outer circumference of the electrode assembly 112, and the gap 114 can be as small as possible. In this way, the electrode assembly 112 and the rigid ring 113 can be assembled more easily, and the physical restriction effect of the rigid ring 113 on the electrode assembly 112 can be effective, so as to restrict the expansion of the electrode assembly 112.

[0125] According to some embodiments of the present application, the thickness of the rigid ring 113 may remain constant along the circumference of the rigid ring 113. The thickness t of the rigid ring 113 may satisfy: 10 μm ≤ t ≤ 1000 μm.

[0126] The thickness t of the rigid ring 113 may be any value of 10 μm, 100 μm, 200 μm, 300 μm, 400 μm, 500 μm, 600 μm, 700 μm, 800 μm, 900 μm, and 1000 μm.

[0127] By designing the thickness t of the rigid ring 113 to have a value range of [10 μm, 1000 μm], the thickness of the rigid ring 113 is moderate. The thickness of the rigid ring 113 will not be too thin, so as to be able to physically constrain the electrode assembly 112. The thickness of the rigid ring 113 will not be too thick, so that the rigid ring 113 occupies as little space in the housing 111 as possible, which is conducive to improving the energy density of the battery cell 11. This is also conducive to making the weight of the rigid ring 113 as small as possible, which is conducive to lightweighting the battery cell 11.

[0128] Moreover, since the thickness of the rigid ring 113 is equal at all locations, it is beneficial for the rigid ring 113 to have a similar ability to resist the expansion force applied by the electrode assembly 112 throughout the entire circumference, so that the rigid ring 113 exerts uniform physical constraints on the electrode assembly 112 throughout the entire circumference.

[0129] According to some embodiments of the present application, the elastic modulus E of the material of the rigid ring 113 may be configured to satisfy: E>1 GPa.

[0130] The material of the rigid ring 113 may be, but is not limited to, pure metals such as iron, steel, copper, and aluminum, or alloys containing iron, steel, copper, or aluminum (e.g., nickel-chromium steel, alloy steel, and carbon steel), or polymer materials. The polymer material here may specifically be polypropylene (PP) or polyethylene (PE), and the type of polyethylene is not limited to rigid polyvinyl chloride or polytetrafluoroethylene.

[0131] In this embodiment, the elastic modulus of the material of the rigid ring 113 is greater than 1 GPa, indicating that the material of the rigid ring 113 has excellent ability to resist elastic deformation, so that the rigid ring 113 can reliably restrain the electrode assembly 112 to effectively limit the expansion of the electrode assembly 112, and the rigid ring 113 is not easily damaged by the expansion force of the electrode assembly 112.

[0132] According to some embodiments of the present application, Figure 7 As shown, a coating layer 116 may be provided on the outer side of the rigid ring 113, and the coating layer 116 covers the outer peripheral surface of the rigid ring 113. Figure 7 As shown, the coating layer 116 can be a single-layer structure, and the coating layer 116 is an insulating layer. Alternatively, the coating layer 116 can be a multi-layer structure, and the coating layer 116 includes a plurality of sub-layers stacked in sequence along the thickness direction of the rigid ring 113, and at least one of the plurality of sub-layers is an insulating layer.

[0133] That is to say, at least an insulating layer is provided around the outer side of the rigid ring 113, and the insulating layer can play the role of insulating and isolating the rigid ring 113 and the outer shell 111, so that the electrode assembly 112 can be conductively connected to the outer shell 111 through the rigid ring 113, resulting in a low risk of short circuit. In the embodiment in which the coating layer 116 is a multi-layer structure, in addition to the insulating layer, the coating layer 116 can also include an inorganic coating, an organic coating, etc., and the insulating layer can be located in the innermost layer or the outermost layer. Among them, the material of the insulating layer can be selected from any one or more of polyethylene and polypropylene.

[0134] In this embodiment, at least an insulating layer is provided on the outer side of the rigid ring 113 to insulate and isolate the rigid ring 113 from the outer shell 111 , thereby reducing the risk of short circuit caused by the conductive connection of the electrode assembly 112 to the outer shell 111 through the rigid ring 113 .

[0135] According to some embodiments of this application, please continue to refer to Figure 7 The outer side of the electrode assembly 112 may also be surrounded by an isolation layer 117, and the isolation layer 117 is used to insulate and isolate the electrode assembly 112 and the rigid ring 113. The material of the isolation layer 117 can be any one or more of polyethylene and polypropylene.

[0136] By designing an isolation layer 117 outside the electrode assembly 112, the isolation layer 117 can play the role of insulating and isolating the electrode assembly 112 and the rigid ring 113. In this example, there are fewer restrictions on the material of the rigid ring 113, and the rigid ring 113 can be made of metal.

[0137] In the battery cell 11 disclosed herein, the rigid ring 113 may be an integrated structure or a split structure.

[0138] As an example, in the technical solution in which the rigid ring 113 is an integrated structure, the rigid ring 113 can be formed as an integral piece by an integrated molding process such as casting, injection molding, and extrusion molding. Alternatively, the rigid ring 113 can also be made of a metal foil material, and the head and tail ends of the metal foil material are connected by any of welding, adhesive connection, and sewing connection.

[0139] In the example where the ends of the metal foil are connected to form a rigid ring 113, when assembling the rigid ring 113 with the electrode assembly 112, the ends of the metal foil can be sewn together first, so that the metal foil is sewn to form a ring (i.e., the rigid ring 113), and then the electrode assembly 112 is inserted into the rigid ring 113 or the rigid ring 113 is set outside the electrode assembly 112. Alternatively, when assembling the rigid ring 113 with the electrode assembly 112, the electrode assembly 112 can also be first superimposed on one side of the metal foil, the ends of the metal foil are pulled close to each other, so that the metal foil is wrapped outside the electrode assembly 112, the tightness of the metal foil is adjusted, and then the ends of the metal foil are welded, bonded or sewn together to form the rigid ring 113.

[0140] As an example, in the technical solution where the rigid ring 113 is a split structure, the rigid ring 113 can be formed by connecting multiple metal foils end to end in the circumferential direction of the electrode assembly 112, and two adjacent metal foils are connected by any of welding, adhesive connection and suturing connection.

[0141] In the technical solution where the rigid ring 113 is a split structure, please refer to Figure 8 and Fig. 9 The rigid ring 113 may also include a plurality of sub-ring segments 1131 sequentially arranged and connected along the axial direction of the electrode assembly 112 , and the centers of the plurality of sub-ring segments 1131 are collinearly arranged.

[0142] Among them, the processing and manufacturing method of each sub-ring segment 1131 can refer to the manufacturing method of the rigid ring 113, that is, the sub-ring segment 1131 can be formed as an integral part by an integrated molding process such as casting, injection molding, and extrusion molding, or can be formed by connecting the head and tail ends of a metal foil, or can be formed by connecting multiple metal foils in sequence head to tail in the circumferential direction of the electrode assembly 112.

[0143] Due to the colinear arrangement of the centers of the plurality of sub-annular segments 1131 , any two sub-annular segments 1131 will not be offset along the XY plane, so that the inner circumferences of the sub-annular segments 1131 are coplanar.

[0144] In this example, an exemplary assembly process of the rigid ring 113 and the electrode assembly 112 is: S10, stacking multiple sub-ring segments 1131 in sequence from bottom to top, and assembling and connecting the multiple sub-ring segments 1131 into a whole (i.e., the rigid ring 113); S20, inserting the electrode assembly 112 into the rigid ring 113 or putting the rigid ring 113 onto the outside of the electrode assembly 112.

[0145] In this example, another exemplary assembly process of the rigid ring 113 and the electrode assembly 112 is: providing an electrode assembly 112, sequentially inserting a plurality of sub-ring segments 1131 onto the outside of the electrode assembly 112 along the axial direction of the electrode assembly 112, and assembling and connecting the plurality of sub-ring segments 1131 into a whole (i.e., the rigid ring 113).

[0146] It can be seen from the foregoing description that the rigid ring 113 and the electrode assembly 112 are gap-matched, and the gap between the two is relatively small. In this embodiment, the rigid ring 113 is designed to be composed of a plurality of sub-ring segments 1131 arranged in sequence along the axial direction of the electrode assembly 112. Compared with the assembly of the integral rigid ring 113 and the electrode assembly 112, the difficulty of assembling the sub-ring segments 1131 and the electrode assembly 112 can be reduced, which is beneficial to improving the assembly efficiency of the battery cell 11.

[0147] Moreover, with this design, the rigid ring 113 is more flexible in structure and the number of sub-ring segments 1131 can be adaptively adjusted according to the axial height of the electrode assembly 112, so that the rigid ring 113 can be adapted to physically restrict electrode assemblies 112 of different heights.

[0148] According to some embodiments of the present application, any two adjacent sub-annular segments 1131 among the plurality of sub-annular segments 1131 may be connected by any one or more of adhesive connection, clamping connection and welding connection.

[0149] As an example, one of the end faces of two adjacent sub-annular segments 1131 facing each other is provided with a slot, and the other is provided with a snap-fit ​​block that snaps with the slot, so that the two adjacent sub-annular segments 1131 are snap-fitted. It can be understood that the matching relationship between the slot and the snap-fit ​​block in this example can also play an assembly positioning role.

[0150] As an example, two adjacent sub-annular segments 1131 may be welded by a continuous welding process, in which case a continuous weld is formed between the two adjacent sub-annular segments 1131. Alternatively, two adjacent sub-annular segments 1131 may be welded by a spot welding process, in which case an intermittent weld is formed between the two adjacent sub-annular segments 1131.

[0151] As an example, at least one of the end faces of two adjacent sub-annular segments 1131 facing each other may be coated with an adhesive, and the two adjacent sub-annular segments 1131 are bonded and connected by the adhesive. Of course, in other embodiments of the present application, the adhesive may also be replaced by coating the outer surface of the sub-annular segment 1131 and being located at the butt joint of the two adjacent sub-annular segments 1131. As an example, the two adjacent sub-annular segments 1131 may also be bonded and connected by the tape layer 115.

[0152] Thanks to the fact that any two adjacent sub-annular segments 1131 are connected by at least one of bonding, clamping and welding, the structural stability and reliability of the rigid ring 113 assembled from a plurality of sub-annular segments 1131 can be improved.

[0153] Furthermore, with this design, during the process of assembling a plurality of sub-annular segments 1131 into a rigid ring 113, starting from the second sub-annular segment 1131, each time a sub-annular segment 1131 is stacked on the previous sub-annular segment 1131, the sub-annular segment 1131 and the previous sub-annular segment 1131 can be assembled and connected first, so that the stacked sub-annular segments 1131 are fixedly connected. This helps to reduce the risk of the stacked sub-annular segments 1131 being detached due to external forces in the subsequent assembly process, thereby facilitating assembly. Specifically, the implementation process of the above S10 in this example can be: S11, stacking the two sub-annular segments 1131 and making the centers of the two sub-annular segments 1131 collinear; S12, welding or gluing the two sub-annular segments 1131 together, so that the two sub-annular segments 1131 are fixedly connected as a whole; S13, stacking the sub-annular segments 1131 on one side of the whole, making the centers of each sub-annular segment 1131 collinear, and welding or gluing the sub-annular segments 1131 to the whole; S14, repeating S13 until the rigid ring 113 is assembled.

[0154] According to some embodiments of this application, please continue to refer to Figure 8 The battery cell 11 may further include a tape layer 115 , which extends along the axial direction of the electrode assembly 112 , and two ends of the tape layer 115 are respectively bonded to outer surfaces of two sub-annular segments 1131 among the multiple sub-annular segments 1131 .

[0155] As an example, Figure 8 As shown, any two adjacent sub-annular segments 1131 may be connected by bonding through the adhesive tape layer 115. Specifically, any two adjacent sub-annular segments 1131 may be connected by one or more adhesive tape layers 115.

[0156] As an example, all sub-ring segments 1131 may also be connected by the same tape layer 115. In other words, one tape layer 115 is used to simultaneously connect all sub-ring segments 1131, and in this example, both ends of the tape layer 115 extend to both ends of the rigid ring 113 along its own axial direction.

[0157] The tape layer 115 has good adhesive force, so that the connection between the two sub-ring segments 1131 connected by the tape layer 115 is reliable. Moreover, compared with the welding method, the two sub-ring segments 1131 connected by the tape layer 115 can be conveniently connected, and the risk of welding slag splashing onto the electrode assembly 112 and causing damage to the electrode assembly 112 can be reduced.

[0158] The tape layer 115 may be located on the surface of the straight section 1132 of the rigid ring 113 , or may be located on the surface of the arc section 1133 of the rigid ring 113 , and this embodiment does not impose any specific limitation on this.

[0159] According to some embodiments of this application, please continue to refer to Figure 4 and Figure 8 The housing 111 is in a rectangular parallelepiped shape, and the tape layer 115 can be further disposed on the surface of the arc segment 1133 and located in the corner area. The corner area specifically refers to the area of ​​the arc segment 1133 facing the vertical edge of the housing 111.

[0160] Specifically, the tape layer 115 may be disposed adjacent to the connection between the arc segment 1133 and the straight segment 1132. The cross section of the cuboid housing 111 is rectangular.

[0161] Compared with the technical solution in which the tape layer 115 is located on the surface of the straight section 1132 of the rigid ring 113, in this embodiment, the tape layer 115 is arranged in the corner area of ​​the surface of the arc section 1133. The tape layer 115 is generally oriented at a right angle to the cross-section of the outer shell 111, thereby increasing the distance between the tape layer 115 and the outer shell 111. This can help reduce the possibility of contact and friction between the tape layer 115 and the outer shell 111, thereby reducing the risk of damage and warping of the tape layer 115 due to friction, so that the tape layer 115 can maintain the bonding effect during the life cycle of the battery cell 11.

[0162] According to some embodiments of the present application, Fig.10 and Fig.11 As shown, the bottom end of the rigid ring 113 may also be integrally connected with a supporting sheet 118 , and the supporting sheet 118 is connected to the bottom end of the rigid ring 113 in a turning manner and covers the bottom opening of the rigid ring 113 .

[0163] The supporting piece 118 may be integral, in other words, the supporting piece 118 is a one-piece structure. The supporting piece 118 is specifically connected to the bottom end of the straight section 1132 in one piece.

[0164] See also Fig.12 In this example, the manufacturing process of the rigid ring 113 may be as follows: a rectangular metal foil 30 is provided, along Fig.12 The dotted line shown in the figure cuts the rectangular metal foil 30 so that the metal foil becomes a "convex" shape. The "convex" shaped metal foil specifically includes a flat sheet 31 and a supporting sheet 118 which are connected and located in the same plane. The flat sheet 31 is bent along the circumference of the electrode assembly 112 and its two ends are connected to form a rigid ring 113, and then the supporting sheet 118 is folded relative to the rigid ring 113 toward the bottom opening of the rigid ring 113 to cover the bottom opening of the rigid ring 113.

[0165] By designing the support sheet 118, the support sheet 118 can be used to support the electrode assembly 112. Moreover, since the support sheet 118 is integrally connected to the bottom end of the rigid ring 113, the steps of separately manufacturing the support sheet 118 and separately installing the support sheet 118 in the housing 111 can be omitted, which is conducive to improving the manufacturing efficiency of the battery cell 11.

[0166] According to some embodiments of this application, please continue to refer to Fig.10 and Fig.11 The bottom ends of the two straight sections 1132 may respectively extend to form a first sheet 1181 and a second sheet 1182 . The first sheet 1181 and the second sheet 1182 are folded toward each other relative to the rigid ring 113 and may be spliced ​​to form a supporting sheet 118 .

[0167] In other words, the supporting sheet 118 may also be a two-piece structure, specifically formed by splicing a first sheet 1181 and a second sheet 1182 .

[0168] See also Fig.13 In this example, the manufacturing process of the rigid ring 113 may be as follows: a rectangular metal foil 30 is provided, along Fig.13 The dotted lines shown in the figure cut the rectangular metal foil 30 so that the metal foil becomes a rectangular sheet 32, a first sheet 1181 and a second sheet 1182 which are connected and located in the same plane. The first sheet 1181 and the second sheet 1182 protrude from the same side of the rectangular sheet 32 ​​along the width direction of the rectangular sheet 32, and the first sheet 1181 and the second sheet 1182 are spaced apart along the length direction of the rectangular sheet 32; the rectangular sheet 32 ​​is bent along the circumference of the electrode assembly 112 and its head and tail ends are connected to form a rigid ring 113, at which time the rigid ring 113 includes two straight sections 1132 and two arc sections 1133, and the first sheet 1181 and the second sheet 1182 are respectively connected to the two straight sections 1132; then the first sheet 1181 and the second sheet 1182 are folded relative to the rigid ring 113 in a direction close to each other until the first sheet 1181 and the second sheet 1182 are spliced ​​to form a supporting sheet 118.

[0169] In this embodiment, the supporting sheet 118 is integrally connected to the bottom end of the rigid ring 113, which can save the process of separately making the supporting sheet 118 and separately installing the supporting sheet 118 in the housing 111, thereby improving the production efficiency of the battery cell 11. At the same time, compared with the supporting sheet 118 being an integral type, without changing the size of the supporting sheet 118, the size of the first sheet 1181 and the second sheet 1182 can be smaller, and the space required for folding the first sheet 1181 and the second sheet 1182 is smaller.

[0170] According to some embodiments of the present application, the supporting sheet 118 may be provided with a through hole 1183, through which the electrolyte may pass, so that the bottom of the electrode assembly 112 may also be soaked in the electrolyte, thereby facilitating the improvement of the performance of the battery cell 11. As an example, when the supporting sheet 118 is formed by splicing the first sheet 1181 and the second sheet 1182, the through hole 1183 may be provided on the first sheet 1181 and the second sheet 1182.

[0171] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below.

[0172] Embodiment 1

[0173] In the implementation mode of the present application, Figures 3 to 7 As shown, the present application proposes a battery cell 11, including a rectangular shell 111, two electrode assemblies 112 and two rigid rings 113, the two electrode assemblies 112 are arranged in sequence along their own thickness direction, the two rigid rings 113 and the two electrode assemblies 112 correspond one to one, and each electrode assembly 112 is mounted outside a rigid ring 113.

[0174] The electrode assembly 112 includes a straight portion 1121 and two corner portions 1122 . The two corner portions 1122 are respectively disposed at two ends of the straight portion 1121 .

[0175] The elastic modulus of the material of the rigid ring 113 is greater than 1 GPa. The material of the rigid ring 113 can be pure metals such as iron, steel, copper, and aluminum, or alloys containing iron, steel, copper, or aluminum (for example, nickel-chromium steel, alloy steel, and carbon steel), or polymer materials. The shape of the rigid ring 113 is adapted to the shape of the electrode assembly 112, and the rigid ring 113 and the electrode assembly 112 are gap-matched. The rigid ring 113 is in the shape of a runway, and the rigid ring 113 includes two arc segments 1133 and two straight segments 1132 spaced apart along the thickness direction of the electrode assembly 112. Along the circumference of the electrode assembly 112, the arc segments 1133 and the straight segments 1132 are alternately distributed and connected end to end, and the two arc segments 1133 are respectively opposite to the two corner portions 1122.

[0176] A gap 114 is formed between the outer circumference of the electrode assembly 112 and the inner circumference of the rigid ring 113. The gap 114 is a closed ring, so that the outer circumference of the electrode assembly 112 and the inner circumference of the rigid ring 113 are not in contact. Among them, the gap 114 includes two first gaps 1141 and two second gaps 1142 spaced apart along the thickness direction of the electrode assembly 112. The first gap 1141 is arc-shaped, and the first gap 1141 and the second gap 1142 are alternately distributed along the circumference of the electrode assembly 112 and connected end to end. The width w1 of the first gap 1141 and the width w2 of the second gap 1142 are not equal. In addition, the inner circumference L1 of the rigid ring 113 and the outer contour circumference L2 of the electrode assembly 112 satisfy: L2<L1≤L2×110%.

[0177] The thickness of the rigid ring 113 is the same everywhere, and the value range of the thickness t of the rigid ring 113 is [10 μm, 1000 μm].

[0178] An insulating layer is disposed outside the rigid ring 113, and the insulating layer covers the outer circumference of the rigid ring 113 to insulate the rigid ring 113 from the housing 111. An isolation layer 117 is disposed outside the electrode assembly 112, and the isolation layer 117 is used to insulate and isolate the electrode assembly 112 and the rigid ring 113.

[0179] The rigid ring 113 is formed by welding, bonding or sewing the head and tail ends of a metal foil.

[0180] Embodiment 2

[0181] This embodiment is similar to the first embodiment, except that: in the first embodiment, the rigid ring 113 is formed by connecting the head and tail ends of a metal foil by welding or the like, while in this embodiment, the rigid ring 113 includes a plurality of sub-ring segments 1131 arranged and connected in sequence along the axial direction of the electrode assembly 112, the centers of the plurality of sub-ring segments 1131 are arranged in a collinear manner, any two adjacent sub-ring segments 1131 are bonded and connected by a tape layer 115, and the tape layer 115 is located at the corner area of ​​the surface of the arc segment 1133.

[0182] Embodiment 3

[0183] This embodiment is similar to the first embodiment, except that: in this embodiment, the bottom ends of the two straight sections 1132 further extend with a first sheet 1181 and a second sheet 1182, which are both integrally connected to the rigid ring 113, and the first sheet 1181 and the second sheet 1182 are folded toward each other relative to the rigid ring 113 and spliced ​​to form a supporting sheet 118, which is used to support the electrode assembly 112. Through holes 1183 are provided on the first sheet 1181 and the second sheet 1182.

[0184] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them; although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application, and they should all be included in the scope of the claims and specification of the present application. In particular, as long as there is no structural conflict, the various technical features mentioned in the various embodiments can be combined in any way. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions that fall within the scope of the claims.

Claims

1. A battery cell (11), characterized in that: include: Shell (111); an electrode assembly (112) housed in the housing (111), the electrode assembly (112) being a flat winding structure, the electrode assembly (112) comprising a straight portion (1121) and two corner portions (1122), the two corner portions (1122) being respectively arranged at two ends of the straight portion (1121); and A rigid ring (113) is received in the housing (111) and sleeved outside the electrode assembly (112); the shape of the rigid ring (113) matches the shape of the electrode assembly (112); and the rigid ring (113) and the electrode assembly (112) are clearance-matched.

2. The battery cell (11) according to claim 1, characterized in that: The inner circumference of the rigid ring (113) is equal to the outer circumference of the electrode assembly (112), and the inner circumference of the rigid ring (113) is in contact with the outer circumference of the electrode assembly (112).

3. The battery cell (11) according to claim 1, characterized in that: The inner perimeter of the rigid ring (113) is greater than the outer perimeter of the electrode assembly (112), and a gap (114) is formed between the inner perimeter of the rigid ring (113) and the outer perimeter of the electrode assembly (112).

4. The battery cell (11) according to claim 3, characterized in that: The gaps (114) include two first gaps (1141) and two second gaps (1142) spaced apart along the thickness direction of the electrode assembly (112); the first gaps (1141) are arc-shaped; the first gaps (1141) and the second gaps (1142) are alternately distributed along the circumference of the electrode assembly (112) and are connected end to end to form a closed ring.

5. The battery cell (11) according to claim 4, characterized in that: The width w1 of the first gap (1141) is different from the width w2 of the second gap (1142).

6. The battery cell (11) according to claim 3, characterized in that: The inner perimeter L1 of the rigid ring (113) and the outer perimeter L2 of the electrode assembly (112) satisfy the following relationship: L2<L1≤L2×110%.

7. The battery cell (11) according to any one of claims 1 to 6, characterized in that: Along the circumference of the rigid ring (113), the thickness of the rigid ring (113) remains unchanged; the thickness t of the rigid ring (113) satisfies: 10 μm≤t≤1000 μm.

8. The battery cell (11) according to any one of claims 1 to 6, characterized in that: The elastic modulus E of the material of the rigid ring (113) satisfies: E>1 GPa.

9. The battery cell (11) according to any one of claims 1 to 6, characterized in that: The rigid ring (113) comprises a plurality of sub-ring segments (1131) which are sequentially arranged and connected along the axial direction of the electrode assembly (112), and the centers of the plurality of sub-ring segments (1131) are arranged in a collinear manner.

10. The battery cell (11) according to claim 9, characterized in that: The connection method between any two adjacent sub-annular segments (1131) among the plurality of sub-annular segments (1131) is at least one of an adhesive connection, a clamping connection and a welding connection.

11. The battery cell (11) according to claim 9, characterized in that: It also comprises a tape layer (115), the tape layer (115) extending along the axial direction of the electrode assembly (112), and the two ends of the tape layer (115) being respectively bonded and connected to the outer surfaces of two sub-annular segments (1131) of the plurality of sub-annular segments (1131).

12. The battery cell (11) according to claim 11, characterized in that: The housing (111) is in the shape of a rectangular parallelepiped; the rigid ring (113) has two arc segments (1133), the two arc segments (1133) are respectively oriented toward the two corner portions (1122), and the arc segments (1133) have corner regions oriented toward the vertical edges of the housing (111); The adhesive tape layer (115) is arranged on the surface of the arc segment (1133) and is located in the corner area.

13. The battery cell (11) according to any one of claims 1 to 6, characterized in that: A coating layer (116) is further provided on the outside of the rigid ring (113), and the coating layer (116) covers the outer peripheral surface of the rigid ring (113); the coating layer (116) is a single-layer structure, and the coating layer (116) is an insulating layer, or the coating layer (116) includes a plurality of sub-layers stacked in sequence along the thickness direction of the rigid ring (113), and at least one of the plurality of sub-layers is an insulating layer; And / or, an isolation layer (117) is provided on the outer ring of the electrode assembly (112), and the isolation layer (117) is used to insulate and isolate the electrode assembly (112) and the rigid ring (113).

14. The battery cell (11) according to any one of claims 1 to 6, characterized in that: The bottom end of the rigid ring (113) is integrally connected with a supporting sheet (118), and the supporting sheet (118) is connected to the bottom end of the rigid ring (113) in a turning manner and covers the bottom opening of the rigid ring (113).

15. The battery cell (11) according to claim 14, characterized in that: The rigid ring (113) comprises two arc segments (1133) and two straight segments (1132) arranged at intervals along the thickness direction of the electrode assembly (112); the arc segments (1133) and the straight segments (1132) are alternately distributed along the circumference of the electrode assembly (112) and are connected end to end; A first sheet (1181) and a second sheet (1182) are respectively extended from the bottom ends of the two straight sections (1132); the first sheet (1181) and the second sheet (1182) are folded towards each other relative to the rigid ring (113) and spliced ​​to form the supporting sheet (118).

16. A battery device (100), characterized in that: Comprising a battery cell (11) as claimed in any one of claims 1 to 15.

17. An electrical equipment, characterized in that: The electrical equipment comprises the battery device (100) as claimed in claim 16, and the battery device (100) is used to provide electrical energy.

18. An energy storage device, characterized in that: Comprising the battery device (100) as claimed in claim 16.

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