Battery monomer, battery device and electric device

Abstract

The embodiment of the utility model discloses a battery monomer, a battery device and a power utilization device. The battery monomer comprises a shell, a first electrode assembly and a supporting wall, the first electrode assembly is housed within the housing. The supporting wall is arranged opposite to the surface, with the largest surface area, of the first electrode assembly, the supporting wall comprises two sub-walls and a supporting structure, the two sub-walls are oppositely arranged in the first direction, and the supporting structure is connected with the two sub-walls. The supporting structure is obliquely arranged relative to the two sub-walls, and the supporting wall is compressed under the condition that the pressure borne by the supporting wall is larger than or equal to a first threshold value, so that the first electrode assembly can be bound when the expansive force of the first electrode assembly is small, and an expansion space is provided for the first electrode assembly when the expansive force of the first electrode assembly is large; and the reliability of the whole cycle of the battery monomer can be improved.

Description

Technical Field

[0001] This application relates to the field of batteries, and more specifically, to a battery cell, a battery device, and an electrical device. Background Technology

[0002] In current battery cells, the electrode components may undergo periodic expansion and contraction during charging and discharging. If this expansion is not restrained in the early stages of battery cell cycling, there is a risk of reduced battery cell lifespan. However, as the battery cell's usage time increases, the expansion of the electrode components gradually increases in the later stages of cycling. The electrode components may require more expansion space, and introducing thicker buffers will occupy a large space, reducing the performance of the battery cell.

[0003] Therefore, improving the reliability of individual battery cells has become an urgent problem to be solved. Utility Model Content

[0004] This application provides a battery cell, a battery device, and an electrical device, which can improve the reliability of the battery cell throughout its entire life cycle.

[0005] In a first aspect, a battery cell is provided, comprising a housing, a first electrode assembly, and a support wall. The first electrode assembly is housed within the housing. The support wall is disposed within the housing, and is positioned opposite to the surface of the first electrode assembly with the largest surface area. The support wall includes two sub-walls and a support structure. The two sub-walls are positioned opposite each other along a first direction, and the support structure connects the two sub-walls respectively. The first direction is the thickness direction of the support wall. The support structure is inclined relative to the two sub-walls, and the support wall is compressed when subjected to a pressure greater than or equal to a first threshold.

[0006] In the technical solution provided by this application embodiment, by providing a support wall opposite to the surface with the largest surface area of ​​the first electrode assembly, a uniform binding force is provided for the first electrode assembly, thereby improving problems such as electrode folding in the first electrode assembly. On the other hand, by providing an inclined support structure between the two sub-walls of the support wall, the support wall can be compressed when the pressure it receives is greater than or equal to a first threshold, thereby providing expansion space for the first electrode assembly, alleviating the problem of lithium plating risk caused by concentrated stress on the first electrode assembly, and thus improving the reliability of the battery cell throughout its entire life cycle.

[0007] In some embodiments, the orthographic projection of the support wall along the first direction covers the orthographic projection of the surface with the largest surface area of ​​the first electrode assembly along the first direction.

[0008] In the technical solution provided in this application embodiment, the orthographic projection of the support wall along the first direction covers the orthographic projection of the surface with the largest surface area of ​​the first electrode assembly along the first direction, which can reduce the possibility of damage caused by the scratching of the surface with the largest surface area of ​​the first electrode assembly with the support wall, thereby improving the reliability of the battery cell.

[0009] In some embodiments, the orthographic projection of the support wall along the first direction covers the orthographic projection of the first electrode assembly along the first direction.

[0010] In the technical solution provided in this application embodiment, when the orthographic projection of the support wall along the first direction covers the orthographic projection of the first electrode assembly along the first direction, even if the corner area of ​​the first electrode assembly is squeezed against the support wall, the corner of the support wall is not easy to scratch the first electrode assembly, thereby improving the reliability of the battery cell.

[0011] In some embodiments, support walls are disposed on both sides of the first electrode assembly along a first direction, and the support walls are located between the first electrode assembly and the housing.

[0012] In the technical solution provided in this application embodiment, the support wall is disposed on both sides of the first electrode assembly along the first direction, and the support wall is located between the first electrode assembly and the outer shell, which can provide balanced support force on both sides of the first electrode assembly, thereby improving the risk of uneven current density distribution caused by uneven force on the first electrode assembly, and thus improving the stability of the battery cell.

[0013] In some embodiments, the housing includes two sidewalls disposed opposite to each other along a first direction. The distance between the two sidewalls is d1, the thickness of the first electrode assembly along the first direction is d2, and the thickness d0 of the support wall satisfies 0.02d1≤d0≤(0.97d1-d2) / 2.

[0014] In the technical solution provided in this application embodiment, the thickness d0 of the support wall satisfies 0.02d1<d0≤(0.97d1-d2) / 2, which ensures that when the first electrode assembly enters the casing, the thickness margin of the support wall and the first electrode assembly in the battery cell within the casing is less than or equal to 97%, that is, the percentage of the thickness of the support wall and the first electrode assembly to the thickness of the casing cavity is less than or equal to 97%. On the one hand, this allows the first electrode assembly to enter the casing smoothly; on the other hand, it reserves some expansion space for the first electrode assembly, thereby improving the reliability of the battery cell.

[0015] In some embodiments, a support wall is disposed on one side of the first electrode assembly along a first direction, and the support wall is located between the first electrode assembly and the housing.

[0016] In the technical solution provided in this application embodiment, the support wall is disposed on one side of the first electrode assembly along the first direction, and the support wall is located between the first electrode assembly and the outer shell. When the support wall is compressed, the support wall can provide a larger expansion space for the first electrode assembly, thereby improving the life of the battery cell and thus improving the stability of the battery cell.

[0017] In some embodiments, the housing includes two sidewalls disposed opposite to each other along a first direction. The distance between the two sidewalls is d1, the thickness of the first electrode assembly along the first direction is d2, and the thickness d0 of the support wall satisfies 0.04d1≤d0≤(0.97d1-d2).

[0018] In some embodiments, the battery cell further includes a second electrode assembly housed within a housing. The second electrode assembly is disposed opposite to the surface of the first electrode assembly having the largest surface area, and a support wall is disposed between the first and second electrode assemblies.

[0019] In the technical solution provided in this application embodiment, a support wall is provided between the surfaces with the largest surface areas of the first electrode assembly and the second electrode assembly. When the first electrode assembly and the second electrode assembly expand, the support wall can disperse the concentrated stress and apply it evenly to the surfaces of the first electrode assembly and the second electrode assembly, thereby reducing the risk of lithium plating caused by stress concentration between the first electrode assembly and the second electrode assembly, and thus improving the reliability of the battery cell.

[0020] In some embodiments, when the pressure on the support wall is less than a first threshold, the angle α1 between the support structure and the two sub-walls satisfies 15°≤α1≤75°.

[0021] In some embodiments, the first threshold is greater than or equal to 2000N and less than or equal to 6000N.

[0022] In the technical solution provided in this application embodiment, the first threshold of the pressure of the support wall being compressed can be adjusted according to different types of battery cells, so as to better adapt to different types of battery cells and further improve the reliability of battery cells.

[0023] In some embodiments, the support wall is fully compressed when subjected to a pressure greater than or equal to a second threshold.

[0024] In some embodiments, when the pressure on the support wall is greater than or equal to the second threshold, the angle α2 between the support structure and the two sub-walls satisfies 0°≤α2<15°.

[0025] In some embodiments, the second threshold is greater than or equal to 2500N and less than or equal to 9000N.

[0026] In the technical solution provided in this application embodiment, the second threshold of the pressure at which the support wall is fully compressed can be adjusted according to different types of battery cells, thereby better adapting to different types of battery cells and further improving the reliability of the battery cells.

[0027] In some embodiments, the material of the support wall is selected from one of the following: metal, plastic, or high molecular weight organic material.

[0028] In some embodiments, the substrate of the support wall comprises aluminum.

[0029] In the technical solution provided in this application embodiment, the material of the support wall includes aluminum. On the one hand, this is beneficial to improving the energy density of the battery cell. On the other hand, the corrosion resistance, thermal conductivity, and excellent ductility of aluminum can further improve the stability of the battery cell.

[0030] In some embodiments, the number of support structures is greater than or equal to 2 and less than or equal to 50.

[0031] In some embodiments, the support structure is a support inclined plate, and the thickness d3 of the support inclined plate satisfies 0.2mm≤d3≤2mm.

[0032] In a second aspect, a battery device is provided, the battery device comprising a battery cell as described in any of the first aspects.

[0033] Thirdly, an electrical device is provided, comprising a battery cell as described in any of the first aspects, wherein the battery cell is used to provide electrical energy. Or, as described in the second aspect, wherein the battery device is used to provide electrical energy. In some embodiments, the electrical device is a vehicle, a ship, or a spacecraft. Attached Figure Description

[0034] Figure 1 A schematic diagram of the structure of a vehicle according to one embodiment of this application is shown;

[0035] Figure 2 A partial structural schematic diagram of the battery device according to an embodiment of this application is shown;

[0036] Figure 3 An exploded view of a battery cell provided in an embodiment of this application is shown;

[0037] Figure 4 A partial top view of a battery cell in one embodiment of this application is shown;

[0038] Figure 5 A partial top view of a battery cell provided in a certain embodiment of this application is shown;

[0039] Figure 6A partial top view of a battery cell provided in a certain embodiment of this application is shown;

[0040] Figure 7 A partial top view of a battery cell provided in a certain embodiment of this application is shown;

[0041] Figure 8 This application shows Figure 7 An enlarged schematic diagram of part A of the battery cell provided in the diagram;

[0042] Figure 9 This application shows Figure 7 An enlarged schematic diagram of part A in a single battery cell when the supporting wall is fully compressed;

[0043] Figure 10 This application illustrates a possible expansion force testing apparatus according to one embodiment;

[0044] Figure 11 The expansion force-expansion rate curve of a single cell in one embodiment of this application is shown;

[0045] Figure label:

[0046] 1-Vehicle; 10-Battery Unit; 20-Battery Cell; 21-Casing; 22-Electrode Assembly; 23-Support Wall; 30-Controller; 40-Motor; 11-Box; 111-First Box Section; 112-Second Box Section; 211-Housing Shell; 212-End Cap; 214-Electrode Terminal; 214a-First Electrode Terminal; 214b-Second Electrode Terminal; 221-First Electrode Assembly; 222-Second Electrode Assembly; 231-Sub-wall; 232-Support Structure; 300-Expansion Force Testing Device; 310-Fixed Component; 320-Mechanical Sensor; 330-Thin Film Sensor; 340-Aluminum Plate;

[0047] The accompanying drawings are not drawn to scale. Detailed Implementation

[0048] The technical solutions in the embodiments of this application will now be described with reference to the accompanying drawings.

[0049] 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 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.

[0050] 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 description 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 description, claims, and accompanying drawings of this application are intended to cover non-exclusive inclusion. The terms "first," "second," etc., in the description, claims, or accompanying drawings of this application are used to distinguish different objects, not to describe a specific order or hierarchy.

[0051] In this application, the reference to "embodiment" means that a specific 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 throughout the specification does not necessarily refer to the same embodiment, nor is it a mutually exclusive, independent, or alternative embodiment. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described in this application can be combined with other embodiments.

[0052] 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.

[0053] 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.

[0054] 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.

[0055] In this application, "multiple" refers to two or more (including two), and similarly, "multiple groups" refers to two or more (including two), and "multiple pieces" refers to two or more (including two).

[0056] Unless otherwise specified, all embodiments and optional embodiments of this application can be combined to form new technical solutions.

[0057] In this embodiment of the application, the battery cell can be a secondary battery, which refers to a battery cell that can be recharged to activate the active materials and continue to be used after the battery cell has been discharged.

[0058] The battery cell can be a lithium-ion battery, sodium-ion battery, sodium-lithium-ion battery, lithium metal battery, sodium metal battery, lithium-sulfur battery, magnesium-ion battery, nickel-metal hydride battery, nickel-cadmium battery, lead-acid battery, etc., and the embodiments of this application are not limited to this.

[0059] A single battery cell typically includes an electrode assembly. The electrode assembly includes a positive electrode, a negative electrode, and a separator. During the charging and discharging process of a single battery cell, active ions (such as lithium ions) repeatedly insert and extract between the positive and negative electrodes. The separator, positioned between the positive and negative electrodes, prevents short circuits while allowing active ions to pass through.

[0060] In some embodiments, the positive electrode may be a positive electrode sheet, which may include a positive electrode current collector and a positive electrode active material disposed on at least one surface of the positive electrode current collector.

[0061] In some embodiments, the negative electrode may be a negative electrode sheet, which may include a negative electrode current collector and a negative electrode active material disposed on at least one surface of the negative electrode current collector.

[0062] As an example, the negative electrode current collector has two surfaces opposite each other in its own thickness direction, and the negative electrode active material is disposed on either or both of the two opposite surfaces of the negative electrode current collector.

[0063] In some embodiments, the electrode assembly further includes an isolator disposed between the positive and negative electrodes.

[0064] In some embodiments, the separator is a separator membrane. This application does not impose any particular limitation on the type of separator membrane; any known porous separator membrane with good chemical and mechanical stability can be selected.

[0065] In some embodiments, the battery cell also includes an electrolyte, which acts as a conductor of ions between the positive and negative electrodes. This application does not impose specific limitations on the type of electrolyte; it can be selected according to requirements. The electrolyte can be liquid, gel, or solid.

[0066] In some embodiments, the electrode assembly is provided with tabs that allow current to be drawn from the electrode assembly. The tabs include a positive tab and a negative tab.

[0067] In some embodiments, a battery cell may include a housing. The housing is used to encapsulate components such as electrode assemblies and electrolytes. The housing includes a casing and end caps.

[0068] The battery device mentioned in the embodiments of this application may include a single physical module containing one or more battery cells to provide higher voltage and capacity. When there are multiple battery cells, the multiple battery cells are connected in series, parallel, or mixed via a busbar.

[0069] In some embodiments, the battery device may be a battery pack, which includes a housing and individual battery cells, with the individual battery cells or battery modules housed within the housing.

[0070] In some embodiments, the housing may be part of the vehicle's chassis structure. For example, a portion of the housing may be at least a part of the vehicle's floor, or a portion of the housing may be at least a part of the vehicle's crossbeams and longitudinal beams.

[0071] Currently, judging from market trends, the application of power batteries is becoming increasingly widespread. Power batteries are not only used in energy storage systems such as hydropower, thermal power, wind power, and solar power plants, but also extensively used in electric vehicles such as electric bicycles, electric motorcycles, and electric cars, as well as in military equipment and aerospace. With the continuous expansion of power battery applications, market demand is constantly increasing, and the need for reliable power batteries is also rising.

[0072] In current battery cells, the electrode components may undergo periodic expansion during charging and discharging. If the expansion is excessive, the electrode sheets may wrinkle, potentially reducing the battery cell's lifespan. However, as the battery cell's lifespan increases, the expansion force of the electrode components gradually increases in the later stages of cycling. Furthermore, due to the accumulation of side reaction systems, the electrode components may permanently increase in thickness, gradually increasing the stress on the battery cell's structure. At this point, the battery cell may need to accommodate the expansion of the electrode components to alleviate the increasing stress.

[0073] Therefore, improving the reliability of individual battery cells throughout their entire lifecycle has become an urgent problem to be solved.

[0074] This application provides a battery cell, a battery device, and a power-consuming device, which can improve the reliability of the battery cell throughout its entire life cycle. The battery cell may include a housing, a first electrode assembly, and a support wall. The first electrode assembly is housed within the housing. The support wall is disposed within the housing, and is positioned opposite to the surface of the first electrode assembly with the largest surface area. The support wall includes two sub-walls and a support structure. The two sub-walls are positioned opposite each other along a first direction, and the support structure connects the two sub-walls respectively. The first direction is the thickness direction of the support wall. The support structure is inclined relative to the two sub-walls, and the support wall is compressed when subjected to a pressure greater than or equal to a first threshold.

[0075] In the technical solution provided by this application embodiment, a support wall is provided opposite to the surface with the largest surface area of ​​the first electrode assembly. The support structure within the support wall provides a binding force to restrain the expansion of the surface with the largest surface area of ​​the first electrode assembly. Furthermore, the support structure is inclined. When the expansion force exceeds a first threshold, the inclined support structure allows the support wall to be compressed, thereby providing space for the expansion of the first electrode assembly and improving the reliability of the battery cell throughout its entire life cycle.

[0076] The technical solutions described in the embodiments of this application are applicable to various electrical devices that use battery devices.

[0077] Electrical equipment can include vehicles, mobile phones, portable devices, laptops, ships, spacecraft, electric toys, and power tools, etc. Vehicles can be gasoline-powered cars, natural gas-powered cars, or new energy vehicles; new energy vehicles can be pure electric vehicles, hybrid electric vehicles, or range-extended electric vehicles, etc. Spacecraft include airplanes, rockets, space shuttles, and spacecraft, etc. Electric toys include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc. Power tools include metal cutting power tools, grinding power tools, assembly power tools, and railway power tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers, etc. This application does not impose any special limitations on the above-mentioned electrical equipment.

[0078] For ease of explanation, the following embodiments use a vehicle as an example of electrical equipment.

[0079] For example, Figure 1This illustration shows a structural diagram of a vehicle 1 according to one embodiment of this application. Vehicle 1 can be a gasoline-powered vehicle, a natural gas-powered vehicle, or a new energy vehicle. New energy vehicles can be pure electric vehicles, hybrid electric vehicles, or range-extended electric vehicles, etc. A motor 40, a controller 30, and a battery device 10 can be installed inside vehicle 1. The controller 30 controls the battery device 10 to supply power to the motor 40. For example, the battery device 10 can be installed at the bottom, front, or rear of vehicle 1. The battery device 10 can be used to power vehicle 1; for example, it can serve as the operating power source for the vehicle 1's electrical system, such as meeting the power requirements for starting, navigation, and operation. In another embodiment of this application, the battery device 10 can not only serve as the operating power source for vehicle 1 but also as the driving power source, replacing or partially replacing gasoline or natural gas to provide driving power to vehicle 1.

[0080] For example. Figure 2 A partial structural schematic diagram of the battery device 10 according to an embodiment of this application is shown. Figure 2 As shown, the battery device 10 of this application embodiment may include a plurality of battery cells 20 to meet different power usage requirements. The shape of the battery cell 20 in this application embodiment can be set according to actual application. For example, the battery cell 20 can be as follows: Figure 2 The square shown, or it could be different. Figure 2 The embodiments shown are cylindrical or other shapes, but are not limited to these.

[0081] It should be understood that, such as Figure 2 As shown, the battery device 10 of this embodiment may further include a housing 11, which can be used to accommodate multiple battery cells 20. The housing 11 of this embodiment has a hollow interior, and the multiple battery cells 20 are accommodated within the housing 11. The housing 11 may include two parts, referred to herein as a first housing portion 111 and a second housing portion 112, which are fastened together. The shapes of the first housing portion 111 and the second housing portion 112 can be determined according to the shape of the components housed inside, for example, according to the shape of the combination of the multiple battery cells 20 housed inside. At least one of the first housing portion 111 and the second housing portion 112 has an opening. For example, as... Figure 2As shown, the first housing portion 111 and the second housing portion 112 can both be hollow cuboids with one open side each. The openings of the first housing portion 111 and the second housing portion 112 are opposite to each other, and the first housing portion 111 and the second housing portion 112 are interlocked to form a housing 11 with a closed chamber, which can be used to accommodate multiple battery cells 20. The multiple battery cells 20 are connected in parallel, series, or mixed and placed inside the housing 11 formed by the interlocking of the first housing portion 111 and the second housing portion 112.

[0082] For example, unlike Figure 2 As shown, either the first housing portion 111 or the second housing portion 112 may have only one hollow cuboid with an opening, while the other is plate-shaped to cover the opening. Taking the second housing portion 112 as a hollow cuboid with one opening and the first housing portion 111 as a plate-shaped example, then the first housing portion 111 covers the opening of the second housing portion 112 to form a housing 11 with a closed chamber, which can be used to accommodate multiple battery cells 20.

[0083] For example, unlike Figure 2 As shown, only one of the first box portion 111 and the second box portion 112 may be a hollow cuboid with an opening, while the other may be plate-shaped to cover the opening. For example, taking the second box portion 112 as a hollow cuboid with only one side being an opening, and the first box portion 111 as a plate-shaped example, then the first box portion 111 covers the opening of the second box portion 112 to form a box 11 with a closed cavity. The embodiments of this application are not limited to this.

[0084] Please refer to the following together. Figure 3 This application describes the overall structure of the battery cell 20 provided in the embodiments.

[0085] Figure 3 An exploded view of a battery cell 20 provided in one embodiment of this application is shown.

[0086] like Figure 3 As shown, a battery cell 20 is provided according to some embodiments of this application. The battery cell 20 may include a housing 21 and an electrode assembly 22. The housing 21 may include a casing 211 and an end cap 212. Specifically, the casing 211 may be a hollow structure with an opening, and the end cap 212 may cover the opening of the casing 211 so that the electrode assembly 22 can be accommodated inside the casing 21. The bottom wall of the casing 211 may be integrally formed with the other walls of the casing 211, or the bottom wall of the casing 211 may be formed independently of the other walls and then welded to the other walls. This application does not limit this aspect.

[0087] Corresponding to different shapes of battery cells 20, the casing 211 of the battery cell 20 can have various shapes. For example, such as... Figure 3 In this embodiment, the description mainly uses a hollow cuboid structure of the housing 211 as an example. Alternatively, this embodiment mainly uses a hollow structure with an opening at one end of the housing 211 as an example. However, the relevant descriptions of this embodiment are also applicable to battery cells 20 of other shapes; for the sake of brevity, they will not be elaborated upon here.

[0088] In some implementations, such as Figure 3 As shown, the housing 21 is provided with at least two electrode terminals 214, each including at least one first electrode terminal 214a and at least one second electrode terminal 214b, wherein the first electrode terminal 214a and the second electrode terminal 214b have opposite polarities. For example, the first electrode terminal 214a can be a positive electrode terminal, and the second electrode terminal 214b can be a negative electrode terminal; or, the first electrode terminal 214a can be a negative electrode terminal, and the second electrode terminal 214b can be a positive electrode terminal. The positive electrode terminal is used for electrical connection to the positive electrode tab of the electrode assembly 22, and the negative electrode terminal is used for electrical connection to the negative electrode tab of the electrode assembly 22. The positive electrode terminal and the positive electrode tab can be directly connected or indirectly connected, and the negative electrode terminal and the negative electrode tab can be directly connected or indirectly connected.

[0089] The battery cell 20 may also include other structures; for example, the casing 21 may be provided with a pressure relief mechanism. The pressure relief mechanism can release the pressure inside the battery cell 20. This application embodiment does not limit this aspect.

[0090] In the figure, the X direction is the thickness direction of the battery cell 20, the Y direction is the width direction of the battery cell 20, and the Z direction is the height direction of the battery cell 20.

[0091] The following is combined Figure 4 This application describes a battery cell 20 provided in an embodiment.

[0092] Figure 4 A partial top view of a battery cell 20 in one embodiment of this application is shown.

[0093] In some embodiments, the battery cell 20 may include a housing 21, a first electrode assembly 221, and a support wall 23, with the first electrode assembly 221 housed within the housing 21. The support wall 23 is disposed within the housing 21, and is positioned opposite to the surface of the first electrode assembly 221 with the largest surface area. The support wall 23 includes two sub-walls 231 and a support structure 232. The two sub-walls 231 are positioned opposite each other along a first direction, and the support structure 232 connects the two sub-walls 231 respectively. The first direction is the thickness direction of the support wall 23. The support structure 232 is inclined relative to the two sub-walls 231, and the support wall 23 is compressed when subjected to a pressure greater than or equal to a first threshold.

[0094] The figure uses the X direction as an example, but the embodiments of this application are not limited thereto.

[0095] When the battery cell 20 includes only one electrode assembly 22, that single electrode assembly 22 is the first electrode assembly 221. In this embodiment, the battery cell 20 including one electrode assembly 22 is used as an example.

[0096] The supporting wall 23 can be a wall that provides support, and its shape is not limited in this application. For example, the supporting wall 23 can be... Figure 4 The square shown can have rounded corners, or it can have sharp edges.

[0097] The supporting structure 232 can be a supporting inclined plate, supporting inclined ribs, or other structures, and the embodiments of this application are not limited thereto. When the supporting structure 232 includes supporting inclined ribs, the supporting inclined ribs can be arranged in an alternating manner, and the embodiments of this application do not limit this arrangement.

[0098] For example, the support structure 232 may be a set of parallel-arranged support ramps that may extend in a direction parallel to the support wall 23.

[0099] When there are multiple support structures 232, the included angle between the support structure 232 and the two sub-walls 231 can be the same or different, and this application embodiment does not limit this.

[0100] The first electrode assembly 221 may undergo periodic expansion during charging and discharging. When the expansion of the first electrode assembly 221 is large, slippage may occur between the electrodes, and the electrodes may fold, resulting in uneven current density distribution in the first electrode assembly 221 and increasing the possibility of local lithium plating, which may in turn affect the performance of the battery cell 20.

[0101] The surface with the largest surface area of ​​the first electrode assembly 221 is usually the surface where the first electrode assembly 221 expands most violently. By setting the support wall 23 opposite to the surface with the largest surface area of ​​the first electrode assembly 221, the expansion of the first electrode assembly 221 can be uniformly restrained, thus improving the problem of electrode folding and slippage of the battery cell 20.

[0102] In the early stages of cycling of the battery cell 20, the expansion force of the first electrode assembly 221 is small, and the support wall 23 is positioned opposite to the surface with the largest surface area of ​​the first electrode assembly 221, so the support force is evenly distributed and the support force on the first electrode assembly 221 is relatively dispersed, thus having little impact on the first electrode assembly 221.

[0103] In the later stages of battery cell 20 cycling, the expansion force of the first electrode assembly 221 increases, the expansion range of the first electrode assembly 221 also increases, and the required expansion space also increases. At this time, if the structural strength of the support wall 23 is too high, the force on the surface of the first electrode assembly 221 may be too concentrated, resulting in uneven current density distribution of the first electrode assembly 221, which in turn affects the performance of battery cell 20.

[0104] By providing a support structure 232 inclined relative to the two sub-walls 231 between the two sub-walls 231 of the support wall 23, the support wall 23 is almost incompressible when the pressure on the support wall 23 is less than a first threshold, thereby providing a binding force for the first electrode assembly 221. When the pressure on the support wall 23 is greater than or equal to the first threshold, the support structure 232 is further inclined, and the support wall 23 can be compressed, thereby providing expansion space for the first electrode assembly 221.

[0105] The determination of the initial and later stages of the cycle of a single battery cell 20 can be based on the health status of the single battery cell 20, and this application embodiment does not limit this.

[0106] In the technical solution provided in this application embodiment, by providing a support wall 23 opposite to the surface with the largest surface area of ​​the first electrode assembly 221, a uniform binding force is provided to the first electrode assembly 221, thereby improving problems such as electrode folding in the first electrode assembly 221. On the other hand, by providing an inclined support structure 232 between the two sub-walls 231 of the support wall 23, the support wall 23 can be compressed when the pressure it receives is greater than or equal to a first threshold, thereby providing expansion space for the first electrode assembly 221, alleviating the problem of concentrated stress on the first electrode assembly 221, and thus improving the reliability of the battery cell 20 throughout its entire life cycle.

[0107] In some possible embodiments, the orthographic projection of the support wall 23 along the first direction covers the orthographic projection of the surface with the largest surface area of ​​the first electrode assembly 221 along the first direction.

[0108] The first electrode assembly 221 can be divided into a planar region and a corner region. The surface with the largest surface area of ​​the first electrode assembly 221 can be part of the planar region, and the corner region can be understood as the side of the first electrode assembly 221.

[0109] The orthographic projection of the support wall 23 along the first direction covers the orthographic projection of the surface with the largest surface area of ​​the first electrode assembly 221 along the first direction. During the expansion of the first electrode assembly 221, the edges of the support wall 23 are not likely to scratch the surface with the largest surface area of ​​the first electrode assembly 221, thereby reducing the possibility of the support wall 23 causing damage to the first electrode assembly 221.

[0110] In the technical solution provided in this application embodiment, the orthographic projection of the support wall 23 along the first direction covers the orthographic projection of the surface with the largest surface area of ​​the first electrode assembly 221 along the first direction, which can reduce the possibility of damage caused by the surface with the largest surface area of ​​the first electrode assembly 221 rubbing against the support wall 23, thereby improving the reliability of the battery cell 20.

[0111] In some possible embodiments, the two ends of the support wall 23 are provided with rounded corners.

[0112] The rounded corners at both ends of the support wall 23 can reduce the risk of the sharp edges scratching or puncturing the first electrode assembly 221, thereby improving the reliability of the battery cell 20.

[0113] Figure 5 A partial top view of a battery cell 20 provided in one embodiment of this application is shown.

[0114] In some possible embodiments, the orthographic projection of the support wall 23 along the first direction covers the orthographic projection of the first electrode assembly 221 along the first direction.

[0115] In the later stages of the cycle of the battery cell 20, as the expansion of the first electrode assembly 221 increases, the corner area of ​​the first electrode assembly 221 may also be squeezed towards the support wall 23.

[0116] In the technical solution provided in this application embodiment, when the orthographic projection of the support wall 23 along the first direction covers the orthographic projection of the first electrode assembly 221 along the first direction, even if the corner area of ​​the first electrode assembly 221 is squeezed against the support wall 23, the corner of the support wall 23 is not easy to scratch the first electrode assembly 221, thereby improving the reliability of the battery cell 20.

[0117] In some possible embodiments, the support wall 23 is disposed on both sides of the first electrode assembly 221 along the first direction, and the support wall 23 is located between the first electrode assembly 221 and the housing 21.

[0118] The pressure applied to the first electrode assembly 221 may affect the porosity of the electrode, thereby affecting its wetting and causing changes in the ion transport path, leading to the risk of lithium plating. Furthermore, excessive localized stress concentration may worsen the adverse effects of the stress on the first electrode assembly 221.

[0119] Support walls 23 are disposed on both sides of the first electrode assembly 221 along the first direction, and both sides of the first electrode assembly 221 are supported by the support walls 23, thus balancing the forces on both sides of the first electrode assembly 221. During the expansion of the first electrode assembly 221, the supporting forces on both sides of the first electrode assembly 221 are relatively balanced, resulting in uniform mechanical force on the entire first electrode assembly 221. The uniformity of the supporting forces on the two surfaces with the largest surface areas of the first electrode assembly 221 is significantly improved. Therefore, the solution of setting support walls 23 on both sides of the first electrode assembly 221 is more advantageous for battery cells 20 where the thickness of the first electrode assembly 221 is a small percentage of the thickness of the inner cavity of the outer shell 21 or where the inner cavity thickness of the outer shell 21 is large. In addition, some battery cells 20 experience greater expansion force of the first electrode assembly 221 during the initial cycle stage, such as battery cells 20 with silicon-containing negative electrode active materials. The solution of setting support walls 23 on both sides of the first electrode assembly 221 is also effective for battery cells 20 with greater expansion force of the first electrode assembly 221 during the initial cycle stage.

[0120] For example, in battery cells where the positive electrode active material includes ternary polymers (e.g., lithium nickel cobalt manganese oxide batteries), the electrode assembly generates more gas and experiences greater expansion force during the initial stages of cycling. Similarly, in battery cells where the negative electrode active material includes silicon, the electrode assembly also experiences greater expansion force during the initial stages of cycling.

[0121] For example, the electrode assembly of some battery cells includes high-density electrodes (e.g., with a density greater than or equal to 1.7 g / cm³). 3 The graphite negative electrode sheet has a density greater than or equal to 3.5 g / cm³. 3 (Ternary polymer positive electrode sheet) This part of the electrode assembly has a small porosity, which may limit the volume expansion space during lithium ion insertion, resulting in stress concentration and large expansion force of the electrode assembly in the early stage of cycling.

[0122] For example, some battery cells have electrode assemblies including thick electrodes (e.g., electrode thickness greater than or equal to 150 micrometers). This increases the lithium-ion transport path within the electrode assembly, intensifying polarization and potentially leading to uneven expansion and high expansion force in the electrode assembly during the initial cycling phase. For example, battery cells 20 where the thickness of the first electrode assembly 221 when inserted into the casing is a small percentage of the inner cavity thickness of the casing 21 can be battery cells 20 where the thickness margin of the first electrode assembly 221 when inserted into the casing is less than 88.3%.

[0123] In the technical solution provided in this application embodiment, the support wall 23 is disposed on both sides of the first electrode assembly 221 along the first direction, and the support wall 23 is located between the first electrode assembly 221 and the outer shell 21. It can provide balanced support force on both sides of the first electrode assembly 221, thereby improving the risk of uneven current density distribution caused by uneven force on the first electrode assembly 221, and thus improving the stability of the battery cell 20.

[0124] In some possible embodiments, the housing 21 includes two sidewalls disposed opposite to each other along a first direction. The distance between the two sidewalls is d1, the thickness of the electrode assembly 22 along the first direction is d2, and the thickness d0 of the support wall 23 satisfies 0.02d1 < d0 ≤ (0.97d1 - d2) / 2.

[0125] During the assembly of the battery cell 20, some space can be reserved. This reserved space takes into account the structural tolerances of the battery cell 20, so that the first electrode assembly 221 can be smoothly inserted into the outer casing 21 when it is assembled into the casing. On the other hand, this reserved space can also provide a certain amount of expansion space for the first electrode assembly 221.

[0126] In the technical solution provided in this application embodiment, the thickness d0 of the support wall 23 satisfies 0.02d1<d0≤(0.97d1-d2) / 2, which ensures that when the first electrode assembly 221 enters the outer casing 21, the thickness margin of the support wall 23 and the first electrode assembly 221 in the battery cell 20 within the outer casing 21 is less than or equal to 97%, that is, the percentage of the thickness of the support wall 23 and the first electrode assembly 221 to the thickness of the inner cavity of the outer casing 21 is less than or equal to 97%. On the one hand, this allows the first electrode assembly 221 to smoothly enter the outer casing 21; on the other hand, it reserves some expansion space for the first electrode assembly 221, thereby improving the reliability of the battery cell 20.

[0127] Furthermore, the thickness d0 of the support wall 23 can satisfy 0.03d1≤d0≤(0.95d1-d2) / 2. Within this range, the thickness d0 of the support wall 23 can, on the one hand, reduce the difficulty of inserting the first electrode assembly 221 into the casing and provide more expansion space for the first electrode assembly 221. On the other hand, increasing the thickness of the support wall 23 can provide greater restraint for the first electrode assembly 221 in the early stage of battery cell 20 cycling and further provide expansion space for the first electrode assembly 221 in the later stage of battery cell 20 cycling, thereby further improving the reliability of battery cell 20.

[0128] Figure 6 A partial top view of a battery cell 20 provided in one embodiment of this application is shown.

[0129] In some possible embodiments, the support wall 23 is disposed on one side of the first electrode assembly 221 along a first direction, and the support wall 23 is located between the first electrode assembly 221 and the housing 21.

[0130] Compared to providing support walls 23 on both sides of the first electrode assembly 221, providing a support wall 23 on only one side of the first electrode assembly 221 allows for a higher percentage of the thickness of the support wall 23 relative to the inner thickness of the outer casing 21, thus providing greater expansion space for the first electrode assembly 221. This is particularly advantageous for battery cells 20 where the thickness of the first electrode assembly 221 at the time of installation is a large percentage of the inner thickness of the outer casing 21, or where the inner thickness of the outer casing 21 is small. Furthermore, in some battery cells 20, such as those containing silicon in the negative electrode active material, the expansion of the first electrode assembly 221 is significant during the later stages of cycling. The solution of providing a support wall 23 on only one side of the first electrode assembly 221 is also highly effective for battery cells 20 that experience significant expansion during the later stages of cycling.

[0131] For example, in some battery cells, the solvents in the electrode assemblies have low boiling points or are easily decomposed (e.g., propionate carbonate) or use lithium salts (e.g., lithium hexachlorophosphate). During cycling, the gas generation rate is faster, and the expansion rate is quicker. A single-sided support wall 23 helps to provide more expansion space.

[0132] For example, if the electrolyte in some battery cells evaporates quickly or the electrode assembly has poor electrolyte absorption capacity, the impedance of the electrode assembly will increase after the electrolyte dries up, which may lead to an increase in side reactions and thus potentially accelerate the expansion of the electrode assembly. Providing a support wall 23 on one side helps to offer more expansion space.

[0133] For example, if the negative electrode capacity of some individual battery cells is insufficient (e.g., negative electrode capacity / positive electrode capacity ≤ 1.05), lithium dendrites may form, thereby increasing the expansion force. Providing a support wall 23 on one side helps to provide more expansion space.

[0134] For example, the battery cell 20 whose thickness is a large percentage of the inner cavity thickness of the first electrode assembly 221 when it is installed in the casing can be a battery cell 20 whose thickness margin of the first electrode assembly 221 is greater than or equal to 90% when the first electrode assembly 221 is installed in the casing.

[0135] In the technical solution provided in this application embodiment, the support wall 23 is disposed on one side of the first electrode assembly 221 along the first direction, and the support wall 23 is located between the first electrode assembly 221 and the outer shell 21. When the support wall 23 is compressed, the support wall 23 can provide a larger expansion space for the first electrode assembly 221, thereby improving the life of the battery cell 20 and thus improving the stability of the battery cell 20.

[0136] In some possible embodiments, the housing 21 includes two sidewalls disposed opposite each other along a first direction. The distance between the two sidewalls is d1, the thickness of the first electrode assembly 221 along the first direction is d2, and the thickness d0 of the support wall 23 satisfies 0 < d0 ≤ (0.97d1 - d2).

[0137] Furthermore, the thickness d0 of the support wall 23 can satisfy 0.03d1≤d0≤(0.95d1-d2). Within this range, the thickness d0 of the support wall 23 can, on the one hand, reduce the difficulty of inserting the first electrode assembly 221 into the casing and provide more expansion space for the first electrode assembly 221. On the other hand, the thickness of the support wall 23 can further provide greater expansion space for the first electrode assembly 221, thereby further improving the reliability of the battery cell 20.

[0138] Figure 7 A partial top view of a battery cell 20 provided in one embodiment of this application is shown.

[0139] In some possible embodiments, the battery cell 20 further includes a second electrode assembly 222, which is housed within the housing 21. The second electrode assembly 222 is positioned opposite the surface of the first electrode assembly 221 with the largest surface area, and a support wall 23 is disposed between the first electrode assembly 221 and the second electrode assembly 222.

[0140] Figure 7 For example, a battery cell 20 may include two electrode assemblies 22, but the battery cell 20 may include more electrode assemblies 22, such as 3, 4, 6, 8, etc. The embodiments of this application are not limited thereto.

[0141] In the technical solution provided in this application embodiment, a support wall 23 is provided between the surfaces with the largest surface areas of the first electrode assembly 221 and the second electrode assembly 222. When the first electrode assembly 221 and the second electrode assembly 222 expand, the support wall 23 can disperse the concentrated stress and apply it evenly to the surfaces of the first electrode assembly 221 and the second electrode assembly 222, thereby reducing the risk of lithium plating caused by stress concentration between the first electrode assembly 221 and the second electrode assembly 222, and thus improving the reliability of the battery cell 20.

[0142] Figure 8 This application shows Figure 7 An enlarged schematic diagram of part A of the battery cell 20 provided in the diagram.

[0143] In some possible embodiments, when the pressure on the support wall 23 is less than a first threshold, the angle α1 between the support structure 232 and the two sub-walls 231 satisfies 15°≤α1≤75°.

[0144] In the technical solution provided in this application embodiment, when the pressure on the support wall 23 is less than a first threshold, the included angle α1 between the support structure 232 and the two sub-walls 231 satisfies 15°≤α1≤75°. On the one hand, the support structure 232 can provide sufficient support force to counteract the expansion force of the first electrode assembly 221 during the initial cycle of the battery cell 20, and can provide a larger expansion space for the first electrode assembly 221 when the support structure 232 collapses. On the other hand, the support structure 232 has an appropriate tilt angle, which can collapse before the first electrode assembly 221 expands beyond a certain limit. Therefore, the included angle α1 between the support structure 232 and the two sub-walls 231 is within this range, which can improve the reliability of the battery cell 20.

[0145] Furthermore, the included angle α1 between the support structure 232 and the two sub-walls 231 can satisfy 25°≤α1≤65°. α1 being within this range can, on the one hand, provide better restraint for the first electrode assembly 221 in the early stages of battery cell 20 cycling, and on the other hand, provide greater expansion space in the later stages of battery cell 20 cycling.

[0146] In some embodiments, α may also be other values. For example, α1 may be any of the following values ​​or between any two of the following values: 15°, 22.5°, 30°, 37.5°, 45°, 52.5°, 60°, 67.5°, and 75°.

[0147] Figure 9 This application shows Figure 7 An enlarged schematic diagram of part A of the battery cell 20 provided in the diagram when the support wall 23 is fully compressed.

[0148] In some possible embodiments, when the pressure on the support wall 23 is greater than or equal to the second threshold, the angle α2 between the support structure 232 and the two sub-walls 231 satisfies 0°≤α2<15°.

[0149] When the pressure on the support wall 23 is greater than or equal to the first threshold, the angle α2 between the support structure 232 and the two sub-walls 231 satisfies 0°≤α2≤15°, and the support structure 232 can provide a large expansion space for the first electrode assembly 221 after it tilts.

[0150] When the angle α2 between the supporting structure 232 and the two sub-walls 231 is 0°, the supporting structures 232 will not overlap after they fall over.

[0151] For example, the support structure 232 is a support inclined plate, and the spacing between the support inclined plates is greater than the width of the support inclined plate, so that the angle between the support inclined plate and the two sub-walls 231 is 0° after the support inclined plate is tilted, thus providing the maximum expansion space.

[0152] For example, the support structure 232 is a support rib, which is arranged in an alternating manner so that the angle between the support rib and the two sub-walls 231 is 0° after the support rib is tilted.

[0153] Furthermore, when the pressure on the support wall 23 is greater than or equal to the second threshold, the included angle α2 between the support structure 232 and the two sub-walls 231 can satisfy 0°≤α2≤10°. When α2 is within this range, the support wall 23 can provide greater expansion space in the later stages of the battery cell 20 cycle.

[0154] In some embodiments, α may also be other values. For example, α2 may be any of the following values ​​or between any two of the following values: 0°, 2.5°, 5°, 7.5°, 10°, 12.5°, and 15°.

[0155] The following is combined Figure 10 and Figure 11 This application describes the configuration of the support structure 232 in the battery cell 20 provided in the embodiments of this application.

[0156] Figure 10 This application illustrates a possible expansion force testing device 300 according to one embodiment; Figure 11 The expansion force-expansion rate curve of a battery cell 20 in one embodiment of this application is shown.

[0157] like Figure 10 As shown, the expansion force testing device 300 may include fixtures 310. Exemplarily, the number of fixtures 310 in the figure is three, and the fixtures 310 may be steel plates, but this embodiment is not limited to this. A mechanical sensor 320 is disposed between the first fixture 310 and the second fixture 310. The battery cell 20 to be tested is disposed between the second fixture 310 and the third fixture 310. A surface pressure detection component may be disposed between the battery cell 20 and the fixtures 310 to detect the surface pressure distribution. Exemplarily, the surface pressure detection component may be a thin-film sensor 330 as shown in the figure, and an aluminum plate 340 may be disposed between the thin-film sensors 330 to reduce the possibility of thin-film sensor 330 failure.

[0158] The specific testing procedure can be to place the battery cell 20 with the support wall 23 in a position... Figure 10At the indicated location, the battery cell 20 is subjected to charge-discharge cycles. During these cycles, the battery cell 20 expands, and the force sensor 320 records the changes in expansion force. Simultaneously, a distance measuring device can be used to measure the deformation of the battery cell 20. For example, the distance measuring device can be a vision sensor, an infrared sensor, etc., and this embodiment is not limited to this. The expansion rate can be calculated by dividing the deformation in the thickness direction of the battery cell 20 measured by the distance measuring device by the thickness of the inner cavity of the battery cell 20's outer casing 21.

[0159] For example, such as Figure 11 The diagram shows the expansion force-expansion rate curve of the battery cell 20 provided in this embodiment. The base material of the support wall 23 in the battery cell 20 is aluminum, the thickness of the support structure 232 is 0.4 mm, the number of support structures 232 is 8, and the angle between the support structure 232 and the two sub-walls 231 is 30°. At this time, by... Figure 11 It can be seen that within the range of low expansion force of the battery cell 20, the support wall 23 is basically incompressible, and the expansion rate does not increase with the expansion force. When the expansion force is greater than or equal to the first threshold, the support wall 23 is compressed, and the expansion rate increases rapidly. When the expansion force is greater than or equal to the second threshold, the support wall 23 is completely compressed, and the expansion force rises rapidly.

[0160] In some possible embodiments, the first threshold may be greater than or equal to 2000N and less than or equal to 6000N.

[0161] The first threshold can be adjusted according to the type of different battery cells 20. For example, for battery cells 20 that produce more gas and have a more vigorous reaction, the first threshold can be set to a larger value. For example, for battery cells 20 whose positive electrode active material includes nickel and / or whose negative electrode active material includes silicon, the first threshold can be 4000N-6000N. For battery cells 20 with a milder reaction, the first threshold can be set to a smaller value. For example, for lithium iron phosphate batteries, the first threshold can be 2000-4500N. The above are merely examples, and the embodiments of this application are not limited thereto.

[0162] The first threshold can be adjusted by adjusting the material of the support wall 23, for example, by... Figure 10 If the support wall 23 with an aluminum substrate used in the test is replaced with a support wall 23 with a plastic substrate, the first threshold can be reduced to 2000N.

[0163] The first threshold can also be adjusted by adjusting the thickness of the support structure 232. Increasing the thickness of the support structure 232 can increase the first threshold.

[0164] The first threshold can also be adjusted by adjusting the number of support structures 232. Increasing the number of support structures 232 can increase the first threshold.

[0165] The first threshold can also be adjusted by adjusting the angle between the support structure 232 and the two sub-walls 231. Increasing the angle between the support structure 232 and the two sub-walls 231 can reduce the first threshold.

[0166] In the technical solution provided in this application embodiment, the first threshold of the pressure of the support wall 23 being compressed can be adjusted according to different types of battery cells 20, so as to better adapt to different types of battery cells 20 and further improve the reliability of battery cells 20.

[0167] In some possible embodiments, the support wall 23 is fully compressed when subjected to a pressure greater than or equal to a second threshold.

[0168] In some possible embodiments, the second threshold is greater than or equal to 2500N and less than or equal to 9000N.

[0169] The second threshold can be adjusted according to the type of different battery cells 20. For example, for battery cells 20 that produce more gas and have a more vigorous reaction, the second threshold can be set to a larger value. For example, for battery cells 20 whose positive electrode active material includes nickel and / or whose negative electrode active material includes silicon, the second threshold can be 5000N-9000N. For battery cells 20 with a milder reaction, the second threshold can be set to a smaller value. For example, for lithium iron phosphate batteries, the second threshold can be 2500-6000N. The above are merely examples, and the embodiments of this application are not limited thereto.

[0170] The adjustment method for the second threshold can refer to the adjustment method for the first threshold. For example... Figure 11 In the middle, the second threshold is about 6000N. Adjusting the substrate of the support wall 23, the thickness of the support structure 232, the number of support structures 232, and the angle between the support structure 232 and the two sub-walls 231 can make the second threshold range from 2500N to 9000N.

[0171] In the technical solution provided in this application embodiment, the second threshold of the pressure at which the support wall 23 is fully compressed can be adjusted according to different types of battery cells 20, thereby better adapting to different types of battery cells 20 and further improving the reliability of the battery cells 20.

[0172] In some possible embodiments, the material of the support wall 23 may be selected from one or more of the following: metals, plastics, and organic polymers.

[0173] In some possible embodiments, the material of the support wall 23 includes aluminum.

[0174] In terms of lightweighting and energy density optimization, the use of aluminum for the support wall 23 significantly reduces the overall weight of the battery, while the thin-wall design increases the energy density of the individual battery cells 20. This feature is particularly important in electric vehicles and portable devices, balancing structural strength and lightweight requirements.

[0175] Aluminum has a high thermal conductivity, allowing the support wall 23 to quickly conduct heat generated during charging and discharging, reducing the risk of localized overheating. Aluminum also provides both stress dispersion and heat diffusion, effectively suppressing thermal runaway.

[0176] The aluminum alloy support wall 23 is formed by casting or extrusion processes, and has high yield strength and resistance to cyclic fatigue. It can maintain structural stability during long-term charge and discharge expansion and reduce the risk of lithium plating caused by mechanical damage.

[0177] The dense alumina passivation film naturally formed on the aluminum surface can resist electrolyte corrosion, and its oxidation potential is adapted to the positive electrode working voltage range, reducing the possibility of side reactions between the support wall 23 and the first electrode assembly 221.

[0178] Aluminum has excellent ductility, making it suitable for complex forming processes such as stamping and stretching. Aluminum has low processing costs and does not require additional anti-corrosion treatment.

[0179] The aluminum support wall 23, together with the positive electrode aluminum foil current collector and the aluminum shell encapsulation material, forms a synergistic material system, reducing the risk of potential difference corrosion between different metals. Its surface aluminum oxide layer can also improve flame retardancy and thermal stability, thereby enhancing the overall stability of the battery cell 20.

[0180] In the technical solution provided in this application embodiment, the material of the support wall 23 includes aluminum, which on the one hand is beneficial to improving the energy density of the battery cell 20, and on the other hand, the corrosion resistance, thermal conductivity and excellent ductility of aluminum can further improve the stability of the battery cell 20.

[0181] In some possible embodiments, the number of support structures 232 is greater than or equal to 2 and less than or equal to 50.

[0182] For example, the support structure 232 is a support inclined plate. By setting two support inclined plates, sufficient support strength can be provided, and the support wall 23 can be easily compressed.

[0183] For example, the support structure 232 is a support rib. By setting 50 support ribs, sufficient support strength can be provided, and the support wall 23 can be compressed.

[0184] In the technical solution provided in this application embodiment, the number of support structures 232 is greater than or equal to 1 and less than or equal to 50. On the one hand, the support strength of the support structures 232 can provide sufficient support force to resist the expansion force of the first electrode assembly 221 during the initial cycle of the battery cell 20. On the other hand, the appropriate number of support structures 232 can cause them to collapse before the electrode assembly 22 expands beyond a certain limit. Therefore, having the number of support structures 232 within this range can improve the reliability of the battery cell 20.

[0185] Furthermore, the number of support structures 232 can be greater than or equal to 4 and less than or equal to 20. Having the number of support structures 232 within this range allows for better restraint of the first electrode assembly 221 during the early stages of battery cell 20 cycling, and also makes it easier to provide expansion space during the later stages of battery cell 20 cycling.

[0186] In some embodiments, the number of support structures 232 may also be other values. For example, the number of support structures 232 may be any of the following values ​​or between any two of the following values: 2, 3, 4, 6, 8, 10, 15, 20, 25, 30, 40 and 50.

[0187] In some possible embodiments, the support structure 232 is a support inclined plate, and the thickness d3 of the support inclined plate satisfies 0.2mm≤d3≤2mm.

[0188] In the technical solution provided in this application embodiment, the thickness d3 of the supporting inclined plate satisfies 0.2mm≤d3≤2mm. On the one hand, the supporting strength of the supporting structure 232 can provide sufficient supporting force to resist the expansion force of the first electrode assembly 221 during the initial cycle of the battery cell 20. On the other hand, the supporting strength of the supporting structure 232 is not too large, and it can collapse before the first electrode assembly 221 expands beyond a certain limit. Therefore, the thickness d3 of the supporting inclined plate being within this range can improve the reliability of the battery cell 20.

[0189] Furthermore, the thickness d3 of the supporting inclined plate can satisfy 0.3mm≤d3≤1.8mm. The number of supporting structures 232 is within this range, which on the one hand can provide better restraint for the first electrode assembly 221 in the early stage of battery cell 20 cycling, and on the other hand can more easily provide expansion space in the later stage of battery cell 20 cycling.

[0190] In some embodiments, the number of support structures 232 may also be other values. For example, the thickness d3 of the support slope may be any of the following values ​​or between any two of the following values: 0.2mm, 0.29mm, 0.38mm, 0.47mm, 0.56mm, 0.65mm, 0.74mm, 0.83mm, 0.92mm, 1.01mm, 1.1mm, 1.19mm, 1.28mm, 1.37mm, 1.46mm, 1.55mm, 1.64mm, 1.73mm, 1.82mm, 1.91mm, and 2.0mm.

[0191] According to some embodiments of this application, this application also provides a battery device 10, including a battery cell 20 of any of the above schemes.

[0192] According to some embodiments of this application, this application also provides an electrical device including a battery device 10 of any of the above schemes, and the battery device 10 is used to provide electrical energy to the electrical device.

[0193] The power supply device can be any of the aforementioned devices or systems that utilize battery device 10.

[0194] 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 battery cell, characterized in that, include: Outer shell (21); The first electrode assembly (221) is housed within the outer casing (21); A support wall (23) is disposed inside the outer shell (21). The support wall (23) is disposed opposite to the surface with the largest surface area of ​​the first electrode assembly (221). The support wall (23) includes two sub-walls (231) and a support structure (232). The two sub-walls (231) are disposed opposite to each other along a first direction. The support structure (232) connects the two sub-walls (231) respectively. Wherein, the first direction is the thickness direction of the support wall (23), the support structure (232) is inclined relative to the two sub-walls (231), and the support wall (23) is compressed when the pressure it receives is greater than or equal to a first threshold.

2. The battery cell according to claim 1, characterized in that, The orthographic projection of the support wall (23) along the first direction covers the orthographic projection of the surface with the largest surface area of ​​the first electrode assembly (221) along the first direction.

3. The battery cell according to claim 2, characterized in that, The orthographic projection of the support wall (23) along the first direction covers the orthographic projection of the first electrode assembly (221) along the first direction.

4. The battery cell according to claim 1, characterized in that, The support wall (23) is disposed on both sides of the first electrode assembly (221) along the first direction, and the support wall (23) is located between the first electrode assembly (221) and the outer shell (21).

5. The battery cell according to claim 4, characterized in that, The outer casing (21) includes: Two sidewalls, the two sidewalls being disposed opposite to each other along the first direction; Wherein, the distance between the two sidewalls is d1, the thickness of the first electrode assembly (221) along the first direction is d2, and the thickness d0 of the support wall (23) satisfies: 0.02d1≤d0≤(0.97d1-d2) / 2.

6. The battery cell according to claim 1, characterized in that, The support wall (23) is disposed on one side of the first electrode assembly (221) along the first direction, and the support wall (23) is located between the first electrode assembly (221) and the outer shell (21).

7. The battery cell according to claim 6, characterized in that, The outer casing (21) includes: Two sidewalls, the two sidewalls being disposed opposite to each other along the first direction; Wherein, the distance between the two sidewalls is d1, the thickness of the first electrode assembly (221) along the first direction is d2, and the thickness d0 of the support wall (23) satisfies: 0.04d1≤d0≤(0.97d1-d2).

8. The battery cell according to claim 1, characterized in that, The battery cell also includes: The second electrode assembly (222) is housed within the outer casing (21); The second electrode assembly (222) is disposed opposite to the surface with the largest surface area of ​​the first electrode assembly (221), and the support wall (23) is disposed between the first electrode assembly (221) and the second electrode assembly (222).

9. The battery cell according to claim 1, characterized in that, When the pressure on the support wall (23) is less than the first threshold, the angle α1 between the support structure (232) and the two sub-walls (231) satisfies: 15°≤α1≤75°.

10. The battery cell according to claim 1, characterized in that, The first threshold is greater than or equal to 2000N and less than or equal to 6000N.

11. The battery cell according to claim 1, characterized in that, The support wall (23) is fully compressed when subjected to pressure greater than or equal to the second threshold.

12. The battery cell according to claim 11, characterized in that, When the pressure on the support wall (23) is greater than or equal to the second threshold, the angle α2 between the support structure (232) and the two sub-walls (231) satisfies: 0°≤α2<15°.

13. The battery cell according to claim 11, characterized in that, The second threshold is greater than or equal to 2500N and less than or equal to 9000N.

14. The battery cell according to any one of claims 1 to 13, characterized in that, The material of the supporting wall (23) includes: Metals, plastics, and high molecular weight organic compounds.

15. The battery cell according to claim 14, characterized in that, The substrate of the support wall (23) includes aluminum.

16. The battery cell according to any one of claims 1 to 13, characterized in that, The number of the support structures (232) is greater than or equal to 2 and less than or equal to 50.

17. The battery cell according to any one of claims 1 to 13, characterized in that, The supporting structure (232) is a supporting inclined plate, and the thickness d3 of the supporting inclined plate satisfies: 0.2mm≤d3≤2mm.

18. A battery device, characterized in that, The battery device includes: The battery cell as described in any one of claims 1 to 17.

19. An electrical appliance, characterized in that, The electrical device includes: The battery cell according to any one of claims 1 to 17, wherein the battery cell is used to provide electrical energy; or The battery device as claimed in claim 18, wherein, The battery device is used to provide electrical energy.

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