Battery cell, battery device, and electric device

Abstract

The application provides a battery cell, a battery device and a power consumption device. The battery cell comprises a shell and an electrode assembly. The shell has a receiving cavity. The electrode assembly is arranged in the receiving cavity. The electrode assembly comprises a pole piece. The pole piece comprises a current collector and an active material layer arranged on at least one surface of the current collector. The active material layer comprises a capillary recess. A plurality of rows of capillary recesses are arranged along the width direction of the current collector. The capillary recess has an opening facing away from the current collector. The capillary recess comprises a first straight groove, a second straight groove and a third straight groove. One end of each of the first straight groove, the second straight groove and the third straight groove is communicated with each other to form a first communication point. The included angle between the second straight groove and the third straight groove and the first straight groove is an obtuse angle. In at least part of the rows of capillary recesses, any capillary recess in any row is communicated with the first straight groove of the capillary recess in the adjacent row through at least one of the second straight groove and the third straight groove.

Description

Technical Field

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

[0002] Energy conservation and emission reduction are key to the sustainable development of the automotive industry, and electric vehicles, due to their energy-saving and environmentally friendly advantages, have become an important component of this sustainable development. For electric vehicles, battery technology is a crucial factor in their development. Improving battery safety has always been a key research direction in battery technology development. Summary of the Invention

[0003] In view of the above problems, this application provides a battery cell, a battery device, and an electrical device, which are beneficial to improving safety.

[0004] This application provides a battery cell. The battery cell includes a casing and an electrode assembly.

[0005] The housing has a receiving cavity. An electrode assembly is disposed within the receiving cavity. The electrode assembly includes an electrode sheet. The electrode sheet includes a current collector and an active material layer disposed on at least one surface of the current collector. The active material layer includes capillary recesses. Multiple rows of capillary recesses are provided along the width direction of the current collector. The capillary recesses have openings facing away from the current collector. The capillary recesses include a first straight groove, a second straight groove, and a third straight groove. One end of each of the first, second, and third straight grooves is interconnected to form a first connection point. The angle between each of the second and third straight grooves and the first straight groove is an obtuse angle. In at least some rows of capillary recesses, any capillary recess in any row is connected to the first straight groove of a capillary recess in an adjacent row through at least one of the second and third straight grooves.

[0006] In the electrode of this application embodiment, capillary recesses are provided on the active material layer to guide the flow of electrolyte. The wound electrode assembly can be installed into a housing, and electrolyte can be injected into the housing. In the wound electrode assembly, the capillary recesses can generate capillary forces, thereby driving the electrolyte to flow along the capillary recesses and diffuse to the peripheral area of ​​the capillary recesses. This allows more areas on the electrode to be effectively replenished with electrolyte, ensuring that the ion transport efficiency meets the requirements, reducing the possibility of lithium plating problems caused by a lack of electrolyte in local areas of the electrode, and improving the safety of battery cells using the electrode of this application embodiment.

[0007] In some feasible ways, the number of capillary recesses in each row increases along the width direction and from the edge of the active material layer to the middle region.

[0008] The closer to the edge of the active material layer, the fewer the number of capillary recesses. This allows the electrolyte flowing into the capillary recesses to flow relatively quickly into the next row of capillary recesses, which is beneficial for improving the electrolyte wetting rate. Conversely, the closer to the middle region of the active material layer, the more capillary recesses there are. This results in more pathways for electrolyte flow, allowing the electrolyte to flow in more directions and areas along different capillary recesses, which is beneficial for improving the wetting rate and effect of the electrolyte on different areas of the electrode.

[0009] In some feasible ways, the angle between the second and third straight grooves of the capillary recess decreases along the width direction and from the edge of the active material layer to the middle region.

[0010] Along the width direction and from the edge of the active material layer to the middle region, the included angle between the second and third straight grooves of the capillary recess becomes smaller, which reduces the flow resistance of the electrolyte during the flow process from the edge of the active material layer to the middle region. This is beneficial to increasing the wetting rate of the electrolyte climbing from the edge of the active material layer to the middle region of the active material layer, and at the same time, it is beneficial to realize the electrolyte climbing to the middle region of the active material layer, thereby improving the wetting effect on the middle region.

[0011] In some feasible implementations, the included angle between the second and third straight grooves of the capillary recess ranges from 30° to 45°.

[0012] In some feasible ways, the depth of the capillary recess gradually decreases along the width direction and from the edge of the active material layer to the middle region.

[0013] The smaller the depth of the capillary recess, the smaller the cross-sectional area of ​​the capillary recess, which makes the capillary force on the electrolyte relatively greater. This is beneficial to increasing the wetting rate of the electrolyte climbing from the edge of the active material layer to the middle region of the active material layer, and at the same time, it is beneficial to enable the electrolyte to climb to the middle region of the active material layer, thereby improving the wetting effect on the middle region.

[0014] In some feasible ways, there is a gap between the capillary recess and the surface of the active material layer facing the current collector.

[0015] If the capillary recess penetrates the active material layer, on the one hand, there is a possibility that the overall tensile strength of the electrode will decrease, affecting the overall mechanical strength of the electrode, and causing cracks or fractures in the area of ​​the current collector corresponding to the capillary recess; on the other hand, when processing the capillary recess using an etching process, it is easy to etch the current collector, affecting the structural strength of the current collector itself or generating metal debris, which may cause a short circuit between the positive and negative electrode plates through the metal debris.

[0016] In some feasible methods, active material layers are respectively provided on both sides of the current collector along the thickness direction of the current collector, and the sum of the depths of the capillary recesses provided on each of the two active material layers is less than 1 / 4 of the overall thickness of the electrode.

[0017] The overall mechanical strength of the electrode meets product requirements, reducing the possibility of decreased tensile strength due to an excessively large sum of capillary recess depths.

[0018] In some feasible implementations, the electrode includes a tab connected to a current collector, the tab extending in the same direction as the width of the current collector.

[0019] In some feasible ways, at least one row of capillary recesses includes a plurality of interconnected capillary recesses, wherein the second straight groove of one of the interconnected capillary recesses is connected to the third straight groove of another to form a second connection point, and the second connection point is connected to the first straight groove of the capillary recesses of another row.

[0020] For capillary recesses located in the same row and interconnected, the electrolyte can flow into each interconnected capillary recess, so that each interconnected capillary recess can be filled with electrolyte, which is beneficial to improve the wetting rate and wetting effect of the electrolyte.

[0021] In some feasible ways, the individual capillary recesses in each row are not connected to each other, and in at least some rows of capillary recesses, any capillary recess in any row is connected to the first straight groove of a capillary recess in an adjacent row through a second straight groove or a third straight groove.

[0022] After the electrolyte is drawn into the capillary recesses near the edge of the active material layer, the electrolyte can flow to the next capillary recess along the direction from the edge of the active material layer to the middle region. This helps to reduce the shunting of the electrolyte in the direction perpendicular to the width direction, allowing the electrolyte to flow along the interconnected capillary recesses in the width direction. This helps to improve the wetting rate and wetting effect of the electrolyte in the width direction towards the middle region of the active material layer.

[0023] In some feasible methods, three or more rows of capillary recesses are provided along the width direction. In a row of capillary recesses, the first straight groove of the Mth capillary recess is connected to the third straight groove of the (M-1)th capillary recess, where M is an even number. The first straight groove of the Nth capillary recess is connected to the second straight groove of the (N-1)th capillary recess, where N is an odd number greater than 1.

[0024] In a series of capillary recesses, electrolyte drawn into one recess flows into the first straight channel of the next recess through the second or third straight channel; alternatively, electrolyte drawn into one recess flows into the second or third straight channel of the next recess through the first straight channel. Electrolyte flow between two recesses is achieved through a path formed by the first and second straight channels, or by the first and third straight channels. This helps reduce electrolyte diversion and improves the wetting rate and effect of the electrolyte along its width into the middle region of the active material layer.

[0025] In some feasible methods, three or more rows of capillary recesses are provided along the width direction. In a row of capillary recesses, the first straight groove of the Mth capillary recess is connected to the second straight groove of the (M-1)th capillary recess, where M is an even number. The first straight groove of the Nth capillary recess is connected to the third straight groove of the (N-1)th capillary recess, where N is an odd number greater than 1.

[0026] In a series of capillary recesses, electrolyte drawn into one recess flows into the first straight channel of the next recess through the second or third straight channel; alternatively, electrolyte drawn into one recess flows into the second or third straight channel of the next recess through the first straight channel. Electrolyte flow between two recesses is achieved through a path formed by the first and second straight channels, or by the first and third straight channels. This helps reduce electrolyte diversion and improves the wetting rate and effect of the electrolyte along its width into the middle region of the active material layer.

[0027] In some feasible ways, in at least some rows of capillary recesses, the second straight groove and the third straight groove of any capillary recess in any row are respectively connected to the first straight grooves of two capillary recesses in the adjacent row.

[0028] In at least some rows of capillary recesses, in any two adjacent rows of capillary recesses, there are relatively more flow branches formed between the capillary recesses of one row and the capillary recesses of another row, which allows the electrolyte to flow in more directions and areas along different capillary recesses, which is beneficial to improving the wetting rate and wetting effect of the electrolyte on different areas of the electrode.

[0029] In some feasible ways, the individual capillary recesses in each row are not connected.

[0030] After the electrolyte is drawn into the capillary recesses near the edge of the active material layer, it can flow down to the next row of capillary recesses along the direction from the edge of the active material layer to the middle region. The ability of the electrolyte to flow along interconnected capillary recesses in the width direction is beneficial for improving the wetting rate and effect of the electrolyte in the width direction towards the middle region of the active material layer.

[0031] In some feasible ways, the minimum spacing between any two adjacent capillary recesses in each row is greater than 1.5 mm and less than 4 mm.

[0032] In capillary recesses located in the same row, the electrolyte drawn in by the capillary recesses can diffuse to the periphery of the recesses. When the minimum distance D between adjacent capillary recesses is less than or equal to 1.5 mm, the distance between adjacent capillary recesses is relatively close, and there is a possibility of a large overlap in the wetting area after the electrolyte diffuses in adjacent capillary recesses, resulting in low electrolyte utilization. When the minimum distance D between adjacent capillary recesses is greater than or equal to 4 mm, the distance between adjacent capillary recesses is relatively far, and there is a possibility of unwetting areas between the wetting areas after the electrolyte diffuses in adjacent capillary recesses, resulting in the possibility of insufficient electrolyte in unwetting local areas. In the embodiments of this application, the minimum distance D between adjacent capillary recesses is greater than 1.5 mm and less than 4 mm, which helps to solve the above problems and improve the wetting effect of the electrolyte.

[0033] In some feasible embodiments, the active material layer further includes a liquid storage section. Along the width direction, capillary recesses are disposed between the liquid storage section and the edge of the active material layer. In a row of capillary recesses near the liquid storage section, at least one of the second straight groove and the third straight groove of any one capillary recess is provided with a liquid storage section.

[0034] During charging and discharging cycles, the electrode assembly of a single battery cell expands and contracts. During this expansion and contraction, the electrolyte stored in the reservoir is less likely to be squeezed out, allowing it to continue wetting the surrounding area. This improves the wetting effect and reduces the likelihood of lithium plating due to insufficient electrolyte in certain areas of the electrode.

[0035] In some feasible embodiments, the liquid storage section includes a connecting straight channel and a plurality of branch straight channels, the end of each branch straight channel being connected to the end of the connecting straight channel to form a third connection point, and in a row of capillary recesses near the liquid storage section, at least one of the second straight channel and the third straight channel of any capillary recess is connected to the corresponding liquid storage section through the connecting straight channel.

[0036] Electrolyte in a row of capillary recesses near the reservoir flows into the reservoir through corresponding connecting straight channels. The electrolyte flows within the connecting straight channels and then into each branch straight channel. The branch straight channels have reservoir and retention functions. After the electrolyte flows into the branch straight channels, the channels can store the electrolyte, ensuring good reservoir capacity for the reservoir.

[0037] In some feasible embodiments, the liquid storage section includes a connecting straight groove, a communicating groove, and a liquid storage recess. Three or more liquid storage recesses are spaced apart. Any two liquid storage recesses are connected by a communicating groove, and the communicating groove and the liquid storage recess are connected to form a ring structure. The communicating groove or the liquid storage recess is connected to the connecting straight groove. In a row of capillary recesses near the liquid storage section, at least one of the second straight groove and the third straight groove of any one capillary recess is connected to the corresponding liquid storage section through the connecting straight groove.

[0038] Electrolyte in a row of capillary recesses near the liquid storage section flows into the liquid storage section through corresponding connecting straight channels. The electrolyte flows within the connecting straight channels and then to the various connecting channels and liquid storage recesses in the annular structure. The liquid storage recesses have the function of storing and retaining electrolyte. After the electrolyte flows into the liquid storage recesses, the recesses can store the electrolyte, thus ensuring good liquid storage capacity for the liquid storage section.

[0039] In some feasible implementations, the connecting channels and the liquid storage recesses form two or more annular structures.

[0040] The relatively large number of electrolyte storage recesses in two or more annular structures allows the electrolyte storage section to hold a relatively large amount of electrolyte, while the electrolyte stored in the storage section can wet a relatively large area. The electrolyte storage recesses in each annular structure are interconnected, and each electrolyte storage recess has the function of mutually replenishing electrolyte, which helps to improve the electrolyte storage capacity of the electrolyte storage section.

[0041] In some feasible methods, each annular structure is provided with a connecting straight groove, and in a row of capillary recesses near the liquid storage section, the second and third straight grooves of any one capillary recess are each connected to a connecting straight groove.

[0042] The one-to-one correspondence between the number of annular structures and the number of connecting straight grooves facilitates the flow of electrolyte into each annular structure through each connecting straight groove via a relatively short path. This reduces the possibility that electrolyte may fail to reach some of the storage recesses in the annular structure, resulting in a lack of electrolyte in some of these storage recesses.

[0043] In some feasible embodiments, the active material layer includes a first region and a second region arranged along the width direction, both of which are provided with capillary recesses and liquid reservoirs.

[0044] External electrolyte can flow into and to the reservoir of the first region through capillary recesses provided in the first region. External electrolyte can also flow into and to the reservoir of the second region through capillary recesses provided in the second region. The electrolyte can enter the capillary recesses and the reservoir from the two opposite edges of the active material layer along the width direction, which is beneficial to improving the wetting rate and wetting effect of the electrolyte.

[0045] In some feasible embodiments, the capillary recesses in the first region and the capillary recesses in the second region are symmetrically or alternately arranged, and the liquid storage portions in the first region and the liquid storage portions in the second region are symmetrically or alternately arranged.

[0046] The capillary recesses in the first region and the capillary recesses in the second region are alternately arranged. The electrolyte reservoirs in the first region and the second region are also alternately arranged. The electrolyte can wet different regions of the electrode sheet through the capillary recesses and reservoirs in the first region and the capillary recesses and reservoirs in the second region, respectively, thereby improving the wetting effect of the electrolyte.

[0047] The capillary recesses in the first region and the capillary recesses in the second region are symmetrically arranged. The liquid storage sections in the first region and the second region are also symmetrically arranged. The structure and position of the capillary recesses in the first region and the capillary recesses in the second region are mirror images of each other, so that the performance of the capillary recesses in the first region and the capillary recesses in the second region in guiding the electrolyte flow is similar or the same, which is beneficial to improving the consistency of electrolyte wetting effect in the first region and the second region.

[0048] The structures and positions of the liquid storage sections in the first and second regions are mirror images of each other, making their liquid storage and retention properties similar or identical, which helps to improve the consistency of electrolyte wetting effect between the first and second regions.

[0049] In some feasible embodiments, the capillary recesses and liquid storage portions in the first region are not connected to each other with the capillary recesses in the second region.

[0050] In some feasible embodiments, the active material layer includes a first region and a second region arranged along the width direction, both the first region and the second region having capillary recesses, the capillary recesses of the first region and the capillary recesses of the second region being symmetrically or alternately arranged.

[0051] The capillary recesses in the first region and the capillary recesses in the second region are symmetrically arranged. The structure and position of the capillary recesses in the first region and the capillary recesses in the second region are mirror images of each other, so that the capillary recesses in the first region and the capillary recesses in the second region have similar or identical performance in guiding electrolyte flow, which is beneficial to improving the consistency of electrolyte wetting effect in the first region and the second region.

[0052] The capillary recesses in the first region and the capillary recesses in the second region are arranged alternately. The electrolyte can wet different areas of the electrode through the capillary recesses in the first region and the capillary recesses in the second region respectively, thereby improving the wetting effect of the electrolyte.

[0053] In some feasible implementations, the capillary recesses in the first region and the capillary recesses in the second region are not interconnected.

[0054] In some feasible embodiments, the electrode assembly further includes an isolator with an inorganic material film layer disposed on the surface of the isolator facing the electrode. The inorganic material film layer has capillary channels and is disposed on the surface of the isolator facing the electrode. The openings of the capillary recesses are disposed facing the inorganic material film layer.

[0055] The capillary channels of the inorganic material film can guide the electrolyte to flow from the edge of the electrode to the inside of the electrode through capillary forces. The inorganic material film and the corresponding capillary recesses can work together to guide the electrolyte to flow from the edge of the electrode to the inside of the electrode through capillary forces, thereby increasing the electrolyte wetting rate and improving the wetting effect.

[0056] This application provides a battery device that includes the aforementioned battery cell.

[0057] This application provides an electrical device including the battery device described above. The battery device is used to provide electrical energy. Attached Figure Description

[0058] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of this application. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0059] Figure 1 This is a schematic diagram of the structure of a vehicle provided in one embodiment of this application;

[0060] Figure 2 This is a partially exploded structural diagram of a battery device provided in an embodiment of this application;

[0061] Figure 3 This is a schematic diagram of the structure of a battery module provided in one embodiment of the application;

[0062] Figure 4 This is a partially exploded structural diagram of a battery cell provided in an embodiment of this application;

[0063] Figure 5 This is a partial cross-sectional view of the electrode sheet provided in one embodiment of this application;

[0064] Figure 6 This is a partial structural schematic diagram of an electrode sheet provided in an embodiment of this application;

[0065] Figure 7 This is a partial structural schematic diagram of the capillary recess provided in an embodiment of this application;

[0066] Figure 8 This is a partial structural schematic diagram of an electrode sheet provided in an embodiment of this application;

[0067] Figure 9 This is a partial structural schematic diagram of an electrode sheet provided in an embodiment of this application;

[0068] Figure 10 yes Figure 6 Enlarged view of point M in the middle;

[0069] Figure 11 This is a partial structural schematic diagram of an electrode sheet provided in an embodiment of this application;

[0070] Figure 12 This is a partial structural schematic diagram of an electrode sheet provided in an embodiment of this application;

[0071] Figure 13 yes Figure 12 Enlarged view of section V in the middle;

[0072] Figure 14 This is a partial structural schematic diagram of an electrode sheet provided in an embodiment of this application;

[0073] Figure 15 yes Figure 14 Enlarged view of point P in the middle;

[0074] Figure 16 This is a partial structural schematic diagram of an electrode sheet provided in an embodiment of this application;

[0075] Figure 17 yes Figure 16 Enlarged diagram of point S in the middle;

[0076] Figure 18 This is a partial structural schematic diagram of an electrode sheet provided in an embodiment of this application;

[0077] Figure 19 yes Figure 18 Enlarged view of the middle T section;

[0078] Figure 20 This is a partial structural schematic diagram of an electrode sheet provided in an embodiment of this application;

[0079] Figure 21 yes Figure 20 Enlarged view of point E in the middle;

[0080] Figure 22 This is a partial structural schematic diagram of an electrode sheet provided in an embodiment of this application;

[0081] Figure 23 yes Figure 22 Enlarged view of the middle W section;

[0082] Figure 24 This is a partial structural schematic diagram of an electrode sheet provided in an embodiment of this application;

[0083] Figure 25 yes Figure 24 Enlarged view of section H in the middle;

[0084] Figure 26 This is a partial structural schematic diagram of an electrode sheet provided in an embodiment of this application;

[0085] Figure 27 yes Figure 26 Enlarged diagram of the middle U section;

[0086] Figure 28 This is a partial structural schematic diagram of an electrode sheet provided in an embodiment of this application;

[0087] Figure 29 This is a partial structural schematic diagram of an electrode sheet provided in an embodiment of this application;

[0088] Figure 30 yes Figure 29 Enlarged diagram of point G in the middle;

[0089] Figure 31 This is a partial cross-sectional view of an electrode assembly provided in an embodiment of this application.

[0090] Explanation of reference numerals in the attached figures:

[0091] 1. Vehicle; 10. Battery unit; 10a. Housing; 10b. First housing section; 10c. Second housing section; 11. Controller; 12. Motor;

[0092] 20. Battery module; 30. Battery cell; 40. End cap; 41. Electrode terminal; 50. Housing; 60. Electrode assembly; 70. Electrode sheet; 80. Current collector; 90. Active material layer; 91. First region; 92. Second region; 100. Capillary recess; 101. First straight groove; 102. Second straight groove; 103. Third straight groove; 110. Liquid storage section; 110a. Annular structure; 111. Connecting straight groove; 112. Branching straight groove; 113. Connecting groove; 114. Liquid storage recess; 120. Separator; 130. Inorganic material film layer; 140. Tab; 200. First connecting point; 300. Second connecting point; 400. Third connecting point; X, width direction; Y, thickness direction. Detailed Implementation

[0093] The embodiments of the technical solution of this application will now be described in detail with reference to the accompanying drawings. These embodiments are only used to more clearly illustrate the technical solution of this application and are therefore merely examples, and should not be used to limit the scope of protection of this application.

[0094] It should be noted that, unless otherwise stated, the technical or scientific terms used in the embodiments of this application should have the ordinary meaning understood by those skilled in the art to which the embodiments of this application pertain.

[0095] In the description of the embodiments of this application, the technical terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application.

[0096] Furthermore, technical terms such as "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. In the description of the embodiments of this application, "a plurality of" means two or more, unless otherwise explicitly defined.

[0097] In the description of the embodiments of this application, unless otherwise expressly specified and limited, the technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0098] In the description of the embodiments of this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0099] Currently, judging from market trends, the application of battery devices is becoming increasingly widespread. Battery devices are not only used in energy storage power systems such as hydropower, thermal power, wind power, and solar power plants, but also widely applied 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 battery device applications, market demand is also constantly increasing.

[0100] In this application, the battery cell may include a lithium-ion secondary battery cell, a lithium-ion primary battery cell, a lithium-sulfur battery cell, a sodium-lithium-ion battery cell, etc., and the embodiments of this application are not limited thereto. The battery cell may be flat, cuboid, or other shapes, and the embodiments of this application are not limited thereto.

[0101] The battery device mentioned in the embodiments of this application refers to a single physical module comprising one or more battery cells to provide higher voltage and capacity. The battery device mentioned in this application can be a battery pack. For example, the battery device mentioned in this application can include battery modules, etc. A battery device generally includes a housing for encapsulating one or more battery cells. The housing can prevent liquids or other foreign matter from affecting the charging or discharging of the battery cells.

[0102] A single battery cell consists of electrode components and an electrolyte. The electrode components include electrodes and separators. The electrodes are divided into positive and negative electrodes. A single battery cell primarily functions by the movement of metal ions between the positive and negative electrodes. This movement of metal ions occurs through the electrolyte.

[0103] The positive electrode includes a positive current collector and a positive active material layer. The positive active material layer is coated on the surface of the positive current collector. The positive current collector includes a positive current collection section and a positive electrode tab connected to the current collection section. The positive current collection section is coated with the positive active material layer. The positive electrode tab is not coated with the positive active material layer. Taking a lithium-ion battery as an example, the material of the positive current collector can be aluminum. The positive active material layer includes the positive active material. The positive active material can be lithium cobalt oxide, lithium iron phosphate, ternary lithium, or lithium manganese oxide, etc.

[0104] The negative electrode sheet includes a negative electrode current collector and a negative electrode active material layer. The negative electrode active material layer is coated on the surface of the negative electrode current collector. The negative electrode current collector includes a negative electrode current collection section and a negative electrode tab connected to the negative electrode current collection section. The negative electrode current collection section is coated with the negative electrode active material layer. The negative electrode tab is not coated with the negative electrode active material layer. The material of the negative electrode current collector can be copper. The negative electrode active material layer includes the negative electrode active material. The negative electrode active material can be carbon or silicon, etc.

[0105] The material of the separator can include PP (polypropylene) or PE (polyethylene), etc.

[0106] Electrode assemblies are structural components manufactured by winding electrodes and separators. During the winding process, the electrodes and separators are wound along their length. The height of the wound electrode assembly is the same as the width of the electrodes. The wound electrode assembly is then installed into a housing. In wound electrode assemblies, localized electrolyte wettability deviations exist on the electrodes, potentially leading to lithium plating due to insufficient electrolyte in certain areas. During charge and discharge cycles, the electrode assembly expands and contracts, causing electrolyte to be squeezed out, again resulting in lithium plating due to insufficient electrolyte in certain areas. Lithium plating on the electrodes can potentially cause a short circuit between the positive and negative electrodes, affecting the safety of the battery cell.

[0107] To alleviate the problem of localized electrolyte deficiency on the electrode, capillary recesses can be provided on the electrode to assist electrolyte flow and improve electrolyte wettability.

[0108] Based on the above considerations, to alleviate the problem of localized electrolyte deficiency in the electrode, the inventors, after in-depth research, designed an electrode. In this electrode, capillary recesses are formed on the active material layer. In the wound electrode assembly, the capillary force of the capillary recesses can transport electrolyte to areas on the electrode prone to electrolyte deficiency, improving the electrolyte wettability of various areas on the electrode, reducing the possibility of lithium plating problems caused by localized electrolyte deficiency, and improving the safety of the battery cell.

[0109] The technical solutions described in the embodiments of this application are applicable to battery devices and electrical devices that use battery devices.

[0110] Electrical devices can include vehicles, mobile phones, portable devices, laptops, ships, spacecraft, electric toys, and power tools. 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. Spacecraft include airplanes, rockets, space shuttles, and spacecraft. Electric toys include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys. 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. This application does not impose any special limitations on the above-mentioned electrical devices.

[0111] It should be understood that the technical solutions described in the embodiments of this application are not limited to the battery devices and electrical devices described above, but can also be applied to all battery devices including housings and electrical devices using battery devices. However, for the sake of brevity, the following embodiments are all illustrated using electric vehicles as examples.

[0112] See Figure 1 As shown, 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 battery device 10 is installed inside vehicle 1. The battery device 10 can be located at the bottom, front, or rear of vehicle 1. The battery device 10 can be used to power vehicle 1. For example, the battery device 10 can serve as the operating power source for vehicle 1. Vehicle 1 may also include a controller 11 and a motor 12. The controller 11 is used to control the battery device 10 to supply power to the motor 12. For example, this is for the power needs of vehicle 1 during starting, navigation, and driving.

[0113] In some embodiments of this application, the battery device 10 can not only serve as the operating power source for the vehicle 1, but also as the driving power source for the vehicle 1, to replace or partially replace fuel or natural gas to provide driving power for the vehicle 1.

[0114] To meet different power demands, the battery device 10 may include multiple battery cells. A battery cell is the smallest unit that makes up a battery module or battery pack. Multiple battery cells can be connected in series and / or in parallel via electrode terminals for various applications. The battery device mentioned in this application includes a battery module or battery pack. Multiple battery cells can be connected in series, parallel, or a combination thereof. A combination thereof refers to a mix of series and parallel connections. In the embodiments of this application, multiple battery cells can be directly assembled into a battery pack, or they can first be assembled into a battery module, and then the battery modules can be assembled into a battery pack.

[0115] See Figure 2 As shown, the battery device 10 includes a housing 10a and individual battery cells (not shown). The individual battery cells are housed within the housing 10a.

[0116] The housing 10a can be a simple three-dimensional structure such as a single cuboid, cylinder, or sphere, or it can be a complex three-dimensional structure composed of simple three-dimensional structures such as cuboids, cylinders, or spheres. This application embodiment does not limit this. The material of the housing 10a can be an alloy material such as aluminum alloy or iron alloy, or a polymer material such as polycarbonate or polyisocyanurate foam, or a composite material such as glass fiber and epoxy resin. This application embodiment also does not limit this.

[0117] The housing 10a is used to accommodate individual battery cells, and the housing 10a can have various structures. In some embodiments, the housing 10a may include a first housing portion 10b and a second housing portion 10c. The first housing portion 10b and the second housing portion 10c overlap each other. The first housing portion 10b and the second housing portion 10c together define a receiving space for accommodating the individual battery cells. The second housing portion 10c may be a hollow structure with one open end. In some embodiments, the first housing portion 10b is a plate-like structure. The first housing portion 10b overlaps the open side of the second housing portion 10c to form a housing 10a with a receiving space. In some embodiments, both the first housing portion 10b and the second housing portion 10c may also be hollow structures with one open side. The open side of the first housing portion 10b overlaps the open side of the second housing portion 10c to form a housing 10a with a receiving space. Of course, the first housing portion 10b and the second housing portion 10c can have various shapes, such as cylinders, cuboids, etc.

[0118] To improve the sealing performance after the first housing part 10b and the second housing part 10c are connected, a sealing element, such as sealant or sealing ring, can also be provided between the first housing part 10b and the second housing part 10c.

[0119] In some embodiments, the first housing portion 10b covers the top of the second housing portion 10c. The first housing portion 10b may also be referred to as the upper housing cover, and the second housing portion 10c may also be referred to as the lower housing.

[0120] In the battery device 10, there can be one or more battery cells. When there are multiple battery cells, they can be connected in series, parallel, or in a mixed configuration. A mixed configuration means that multiple battery cells are connected in both series and parallel. Multiple battery cells can be directly connected in series, parallel, or in a mixed configuration and then housed within the housing 10a. Alternatively, multiple battery cells can first be connected in series, parallel, or in a mixed configuration to form a battery module. Multiple battery modules can then be connected in series, parallel, or in a mixed configuration to form a whole and housed within the housing 10a.

[0121] In some embodiments, see Figure 3 As shown, there can be multiple battery cells 30. Multiple battery cells 30 are first connected in series, parallel, or in a mixed connection to form a battery module 20. Multiple battery modules 20 are then connected in series, parallel, or in a mixed connection to form a whole, which is housed in the casing 10a.

[0122] Multiple battery cells 30 in the battery module 20 can be electrically connected through a busbar component to achieve parallel, series, or mixed connection of multiple battery cells 30 in the battery module 20.

[0123] In this embodiment, the battery cell 30 may include a lithium-ion battery cell, a sodium-ion battery cell, or a magnesium-ion battery cell, etc., and this embodiment is not limited thereto. The battery cell 30 may be flat, cuboid, or other shapes, and this embodiment is not limited thereto either. However, for the sake of brevity, the following embodiment uses a cuboid battery cell 30 as an example for illustration.

[0124] Battery cell 30 refers to the smallest unit that makes up battery device 10. See also Figure 4 As shown, the battery cell 30 includes an end cap 40, a housing 50, and an electrode assembly 60. The housing 50 has a receiving cavity. The electrode assembly 60 is disposed within the receiving cavity. The electrode assembly 60 includes electrode plates.

[0125] End cap 40 refers to a component that covers the opening of housing 50 to isolate the internal environment of battery cell 30 from the external environment. Exemplarily, the shape of end cap 40 can be adapted to the shape of housing 50 to fit the housing 50. Exemplarily, end cap 40 can be made of a material with a certain hardness and strength (such as aluminum alloy), so that end cap 40 is not easily deformed under pressure or impact, enabling battery cell 30 to have higher structural strength and improved safety performance. Functional components such as electrode terminals 41 can be provided on end cap 40. Electrode terminals 41 can be used for electrical connection with electrode assembly 60 for outputting or inputting electrical energy into battery cell 30.

[0126] In some embodiments, the end cap 40 may also be provided with a pressure relief mechanism for releasing internal pressure when the internal pressure or temperature of the battery cell 30 reaches a threshold. The end cap 40 can be made of various materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., and this application embodiment does not impose any special limitations on this. In some embodiments, an insulating component may also be provided on the inner side of the end cap 40. The insulating component can be used to isolate the electrical connection components within the housing 50 from the end cap 40 to reduce the risk of short circuits. Exemplarily, the insulating component can be plastic, rubber, etc.

[0127] The housing 50 is a component used to cooperate with the end cap 40 to form the internal environment of the battery cell 30. The formed internal environment can accommodate the electrode assembly 60, electrolyte (not shown in the figure), and other components. The housing 50 and the end cap 40 can be independent components. An opening can be provided on the housing 50, and the end cap 40 closes the opening to form the internal environment of the battery cell 30. Alternatively, the end cap 40 and the housing 50 can be integrated. Specifically, the end cap 40 and the housing 50 can form a common connecting surface before other components are inserted into the housing. When it is necessary to encapsulate the interior of the housing 50, the end cap 40 closes the housing 50. The housing 50 can be of various shapes and sizes, such as cuboid, hexagonal prism, etc. Specifically, the shape of the housing 50 can be determined according to the specific shape and size of the electrode assembly 60. The material of the housing 50 can be various, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., and this embodiment does not impose any special limitations on this.

[0128] Electrode assembly 60 is the component in the battery cell 30 where electrochemical reactions occur. The casing 50 may contain one or more electrode assemblies 60. The electrode assembly 60 is mainly formed by winding or stacking positive and negative electrode sheets, and typically a separator is provided between the positive and negative electrode sheets. The portions of the positive and negative electrode sheets containing active material constitute the main body of the electrode assembly. The portions of the positive and negative electrode sheets without active material each constitute a tab. The positive and negative tabs may be located together at one end of the main body or separately at both ends of the main body. During the charging and discharging process of the battery, the positive and negative active materials react with the electrolyte, and the tabs connect the electrode terminals to form a current loop.

[0129] See Figure 5 , Figure 6 and Figure 7 As shown, this application provides an electrode 70, which includes a current collector 80 and an active material layer 90 disposed on at least one surface of the current collector 80.

[0130] An active material layer 90 is disposed on a current collector 80. The active material layer 90 includes capillary recesses 100. Multiple rows of capillary recesses 100 are disposed along the width direction X of the current collector 80. Each capillary recess 100 has an opening facing away from the current collector 80. Each capillary recess 100 includes a first straight groove 101, a second straight groove 102, and a third straight groove 103. One end of each of the first straight groove 101, the second straight groove 102, and the third straight groove 103 is interconnected to form a first connection point 200. The angle between each of the second straight groove 102 and the third straight groove 103 and the first straight groove 101 is an obtuse angle. In at least some rows of capillary recesses 100, any capillary recess 100 in any row is connected to the first straight groove 101 of a capillary recess 100 in an adjacent row through at least one of the second straight groove 102 and the third straight groove 103.

[0131] In this embodiment, the first straight groove 101, the second straight groove 102, and the third straight groove 103 are arranged radially around the first connection point 200. For a single capillary recess 100, the first straight groove 101, the second straight groove 102, and the third straight groove 103 are each connected only at the first connection point 200. In the wound electrode assembly 60, the capillary recess 100 on the electrode 70 can generate capillary forces on the electrolyte, allowing the electrolyte to flow along the first straight groove 101, the second straight groove 102, and the third straight groove 103 under the drive of the capillary forces. The capillary recess 100 can guide the electrolyte from the edge of the electrode 70 to the inner region of the electrode 70 away from the edge, thereby improving the wettability of the electrolyte to different regions of the electrode 70.

[0132] The angles between the second straight groove 102 and the third straight groove 103 and the first straight groove 101 are obtuse angles. This results in a relatively small change in the flow direction of the electrolyte as it flows from the first straight groove 101 into the second straight groove 102 or the third straight groove 103, or as it flows from the second straight groove 102 or the third straight groove 103 into the first straight groove 101. This helps to reduce the flow resistance of the electrolyte and increase the rate at which the electrolyte wets the capillary recess 100.

[0133] The first straight groove 101, the second straight groove 102, and the third straight groove 103 each have a straight extension structure, which makes the flow resistance of the electrolyte relatively small when it flows in the first straight groove 101, the second straight groove 102, or the third straight groove 103, which is beneficial to increasing the rate at which the electrolyte wets through the capillary recess 100.

[0134] In some feasible embodiments, the current collector 80 has two opposing surfaces along its thickness direction Y. At least one of the two surfaces of the current collector 80 is provided with an active material layer 90.

[0135] See also some of the possible implementation methods. Figure 6As shown, in all rows of capillary recesses 100, any capillary recess 100 in any row is connected to the first straight groove 101 of the capillary recess 100 in the adjacent row through at least one of the second straight groove 102 and the third straight groove 103.

[0136] See also some of the possible implementation methods. Figure 8 or Figure 9 As shown, in the capillary recesses 100 of a partial row, any one of the capillary recesses 100 in a row is connected to the first straight groove 101 of the capillary recesses 100 in the adjacent row through at least one of the second straight groove 102 and the third straight groove 103.

[0137] For example, see Figure 8 As shown, along the width direction X, the electrode 70 can be provided with C rows of capillary recesses 100, where 3 ≤ C. In each of the n rows of capillary recesses 100, any one of the capillary recesses 100 in any row is connected to the first straight groove 101 of the capillary recesses 100 in the adjacent row via at least one of the second straight groove 102 and the third straight groove 103. Where 2 ≤ n < C.

[0138] For example, to facilitate understanding of the technical solution, see Figure 8 As shown, taking an example where six rows of capillary recesses 100 are provided on the electrode 70 along the width direction X. Among them, in any row of capillary recesses 100, any capillary recess 100 is connected to the first straight groove 101 of the capillary recess 100 in the adjacent row through at least one of the second straight groove 102 and the third straight groove 103.

[0139] For example, see Figure 9 As shown, along the width direction X, the electrode 70 can be provided with C rows of capillary recesses 100, where 4≤C.

[0140] Among them, n1 rows of capillary recesses 100 constitute the first group of capillary recesses 100. In the n1 rows of capillary recesses 100, any capillary recess 100 in any row is connected to the first straight groove 101 of the capillary recess 100 in the adjacent row through at least one of the second straight groove 102 and the third straight groove 103.

[0141] n2 rows of capillary recesses 100 constitute the second group of capillary recesses 100. The first group of capillary recesses 100 and the second group of capillary recesses 100 are not connected. In the n2 rows of capillary recesses 100, any capillary recess 100 in any row is connected to the first straight groove 101 of the capillary recess 100 in the adjacent row through at least one of the second straight groove 102 and the third straight groove 103.

[0142] Where C = n1 + n2, 2 ≤ n1, 2 ≤ n2.

[0143] For example, to facilitate understanding of the technical solution, see Figure 9 As shown, an example is an electrode 70 with 7 rows of capillary recesses 100 along the width direction X.

[0144] Among them, the three rows of capillary recesses 100 constitute the first group of capillary recesses 100. In the three rows of capillary recesses 100, any one of the capillary recesses 100 in any row is connected to the first straight groove 101 of the capillary recesses 100 in the adjacent row through at least one of the second straight groove 102 and the third straight groove 103.

[0145] The remaining four rows of capillary recesses 100 constitute the second group of capillary recesses 100. In the four rows of capillary recesses 100, any one of the capillary recesses 100 in any row is connected to the first straight groove 101 of the capillary recesses 100 in the adjacent row through at least one of the second straight groove 102 and the third straight groove 103.

[0146] In the electrode 70 of this embodiment, a capillary recess 100 for guiding the flow of electrolyte is provided on the active material layer 90. The wound electrode assembly 60 can be installed in the housing 50, and electrolyte is injected into the housing 50. In the wound electrode assembly 60, the capillary recess 100 can generate capillary force, thereby driving the electrolyte to flow along the capillary recess 100 and diffuse to the peripheral area of ​​the capillary recess 100. This allows more areas on the electrode 70 to be effectively replenished with electrolyte, ensuring that the ion transport efficiency meets the requirements, reducing the possibility of lithium plating problems caused by a lack of electrolyte in local areas of the electrode 70, and improving the safety of the battery cell 30 using the electrode 70 of this embodiment.

[0147] In some possible implementations, the electrode 70 includes a tab 140. The tab 140 is connected to the current collector 80. The tab 140 extends in the same direction as the width direction X of the current collector 80. The tab 140 is disposed on one side of the current collector 80 along the width direction X. For a capillary recess 100, one end of a first straight groove 101 is disposed near the tab 140, while a second straight groove 102 and a third straight groove 103 communicate with the end of the first straight groove 101 away from the tab 140.

[0148] See also some of the possible implementation methods. Figure 7 As shown, the first straight groove 101 extends along the width direction X. The angle K between the second straight groove 102 and the third straight groove 103 and the width direction X is an acute angle.

[0149] See in some examples Figure 7 As shown, the second straight groove 102 and the third straight groove 103 are symmetrically arranged relative to the first straight groove 101.

[0150] See in some examples Figure 6As shown, in all rows of capillary recesses 100, any capillary recess 100 in any row is connected to the first straight groove 101 of two capillary recesses 100 in the adjacent row through the second straight groove 102 and the third straight groove 103, respectively.

[0151] See in some examples Figure 6 and Figure 10 As shown, in any two adjacent rows of capillary recesses 100, the first straight groove 101 of one row of capillary recesses 100 is staggered with the first straight groove 101 of the other row of capillary recesses 100.

[0152] In some feasible methods, capillary recesses 100 are formed on the active material layer 90 by mechanical imprinting. In some examples, a pressure roller with protrusions is used to press the active material layer 90 to form capillary recesses 100 with matching structures.

[0153] In some feasible ways, capillary recesses 100 are formed on the active material layer 90 by laser etching or chemical etching.

[0154] See also some of the possible implementation methods. Figure 10 As shown, at least one row of capillary recesses 100 includes a plurality of interconnected capillary recesses 100. Among the interconnected capillary recesses 100, the second straight groove 102 of one is connected to the third straight groove 103 of another to form a second connection point 300. The second connection point 300 is connected to the first straight groove 101 of the capillary recesses 100 in another row.

[0155] Between two capillary recesses 100 located in the same row and interconnected, electrolyte can flow from the second straight channel 102 of one into the third straight channel 103 of the other, or electrolyte can flow from the third straight channel 103 of one into the second straight channel 102 of the other.

[0156] For capillary recesses 100 located in the same row and interconnected, electrolyte can flow into each interconnected capillary recess 100, so that each interconnected capillary recess 100 can be filled with electrolyte, which is beneficial to improve the wetting rate and wetting effect of electrolyte.

[0157] See in some examples Figure 6 As shown, in all rows of capillary recesses 100, any capillary recess 100 in any row is connected to the first straight grooves 101 of two capillary recesses 100 in the adjacent row through the second straight groove 102 and the third straight groove 103, respectively. For any two adjacent rows of capillary recesses 100, any second connection point 300 in one row is connected to the first straight groove 101 of a capillary recess 100 in the other row.

[0158] See in some examples Figure 11As shown, in at least one row of capillary recesses 100, a portion of the capillary recesses 100 located in the same row are interconnected. Exemplarily, in each row of capillary recesses 100 on the active material layer 90, a portion of the capillary recesses 100 located in the same row are interconnected.

[0159] See in some examples Figure 6 As shown, in at least one row of capillary recesses 100, all capillary recesses 100 located in the same row are interconnected. Exemplarily, all capillary recesses 100 in each row on the active material layer 90 are interconnected. A mesh-like structure can be formed between all the capillary recesses 100 provided on the active material layer 90. The electrolyte can flow in different directions along different capillary recesses 100, which is beneficial to improving the wetting effect of the electrolyte on different areas of the electrode 70.

[0160] See also some of the possible implementation methods. Figures 12 to 15 As shown, the capillary recesses 100 in each row are not interconnected. In each row, no two adjacent capillary recesses 100 are connected. Within the same row, each capillary recess 100 is independently configured. In any two adjacent rows of capillary recesses 100, any one capillary recess 100 in one row is connected to the first straight groove 101 of a capillary recess 100 in the other row via a second straight groove 102 or a third straight groove 103. Multiple rows and columns of capillary recesses 100 can be provided on the active material layer 90.

[0161] After the capillary recesses 100 near the edge of the active material layer 90 absorb the electrolyte, the electrolyte can flow to the next capillary recess 100 along the direction from the edge of the active material layer 90 to the middle region. This helps to reduce the shunting of the electrolyte in the direction perpendicular to the width direction X, allowing the electrolyte to flow along the interconnected capillary recesses 100 in the width direction X. This helps to improve the wetting rate and wetting effect of the electrolyte in the width direction X towards the middle region of the active material layer 90.

[0162] See in some examples Figure 12 and Figure 13 As shown, in all rows of capillary recesses 100, any capillary recess 100 in any row is connected to the first straight groove 101 of a capillary recess 100 in an adjacent row via a third straight groove 103. In any two adjacent rows of capillary recesses 100, the third straight groove 103 of any capillary recess 100 in one row is connected to the first straight groove 101 of a capillary recess 100 in the other row.

[0163] See in some examples Figure 14 and Figure 15As shown, in all rows of capillary recesses 100, any capillary recess 100 in any row is connected to the first straight groove 101 of a capillary recess 100 in an adjacent row via a second straight groove 102. In any two adjacent rows of capillary recesses 100, the second straight groove 102 of any capillary recess 100 in one row is connected to the first straight groove 101 of a capillary recess 100 in the other row.

[0164] See in some examples Figure 16 and Figure 17 As shown, three or more rows of capillary recesses 100 are provided along the width direction X. In a row of capillary recesses 100, the first straight groove 101 of the Mth capillary recess 100 is connected to the third straight groove 103 of the (M-1)th capillary recess 100, where M is an even number. The first straight groove 101 of the Nth capillary recess 100 is connected to the second straight groove 102 of the (N-1)th capillary recess 100, where N is an odd number greater than 1.

[0165] In a row of capillary recesses 100, electrolyte drawn into one capillary recess 100 flows into the first straight channel 101 of the next capillary recess 100 through the second straight channel 102 or the third straight channel 103; alternatively, electrolyte drawn into one capillary recess 100 flows into the second straight channel 102 or the third straight channel 103 of the next capillary recess 100 through the first straight channel 101. Electrolyte flow between two capillary recesses 100 is achieved through a path formed by the first straight channel 101 and the second straight channel 102, or by the first straight channel 101 and the third straight channel 103. This helps reduce electrolyte diversion and improves the wetting rate and effect of the electrolyte in the middle region of the active material layer 90 along the width direction X.

[0166] For example, three rows of capillary recesses 100 are provided along the width direction X. In one row of capillary recesses 100, the first straight groove 101 of the second capillary recess 100 is connected to the third straight groove 103 of the first capillary recess 100, and the first straight groove 101 of the third capillary recess 100 is connected to the second straight groove 102 of the second capillary recess 100.

[0167] For example, four rows of capillary recesses 100 are provided along the width direction X. In one row of capillary recesses 100, the first straight groove 101 of the second capillary recess 100 communicates with the third straight groove 103 of the first capillary recess 100, and the first straight groove 101 of the third capillary recess 100 communicates with the second straight groove 102 of the second capillary recess 100. The first straight groove 101 of the fourth capillary recess 100 communicates with the third straight groove 103 of the third capillary recess 100.

[0168] See in some examples Figure 18 and Figure 19As shown, three or more rows of capillary recesses 100 are provided along the width direction X. In a row of capillary recesses 100, the first straight groove 101 of the Mth capillary recess 100 is connected to the second straight groove 102 of the (M-1)th capillary recess 100, where M is an even number. The first straight groove 101 of the Nth capillary recess 100 is connected to the third straight groove 103 of the (N-1)th capillary recess 100, where N is an odd number greater than 1.

[0169] In a row of capillary recesses 100, electrolyte drawn into one capillary recess 100 flows into the first straight channel 101 of the next capillary recess 100 through the second straight channel 102 or the third straight channel 103; alternatively, electrolyte drawn into one capillary recess 100 flows into the second straight channel 102 or the third straight channel 103 of the next capillary recess 100 through the first straight channel 101. Electrolyte flow between two capillary recesses 100 is achieved through a path formed by the first straight channel 101 and the second straight channel 102, or by the first straight channel 101 and the third straight channel 103. This helps reduce electrolyte diversion and improves the wetting rate and effect of the electrolyte in the middle region of the active material layer 90 along the width direction X.

[0170] For example, three rows of capillary recesses 100 are provided along the width direction X. In one row of capillary recesses 100, the first straight groove 101 of the second capillary recess 100 communicates with the second straight groove 102 of the first capillary recess 100. The first straight groove 101 of the third capillary recess 100 communicates with the third straight groove 103 of the second capillary recess 100.

[0171] For example, four rows of capillary recesses 100 are provided along the width direction X. In one row of capillary recesses 100, the first straight groove 101 of the second capillary recess 100 communicates with the second straight groove 102 of the first capillary recess 100. The first straight groove 101 of the third capillary recess 100 communicates with the third straight groove 103 of the second capillary recess 100. The first straight groove 101 of the fourth capillary recess 100 communicates with the second straight groove 102 of the third capillary recess 100.

[0172] In some examples, the capillary recesses 100 in odd-numbered rows have the same position and shape in the width direction X. The capillary recesses 100 in even-numbered rows have the same position and shape in the width direction X. The capillary recesses 100 in odd-numbered rows are staggered with those in even-numbered rows.

[0173] See in some examples Figure 15 As shown, in each row of capillary recesses 100, the minimum distance D between any two adjacent capillary recesses 100 is greater than 1.5 mm and less than 4 mm.

[0174] In capillary recesses 100 located in the same row, the electrolyte absorbed by the capillary recesses 100 can diffuse to the periphery of the capillary recesses 100. When the minimum distance D between adjacent capillary recesses 100 is less than or equal to 1.5 mm, the distance between adjacent capillary recesses 100 is relatively close, and there is a possibility of a large overlap in the wetting area after the electrolyte diffuses in adjacent capillary recesses 100, resulting in low electrolyte utilization. When the minimum distance D between adjacent capillary recesses 100 is greater than or equal to 4 mm, the distance between adjacent capillary recesses 100 is relatively far, and there is a possibility of unwetting areas between the wetting areas after the electrolyte diffuses in adjacent capillary recesses 100, resulting in the possibility that unwetting local areas still lack electrolyte. In the embodiments of this application, the minimum distance D between adjacent capillary recesses 100 is greater than 1.5 mm and less than 4 mm, which helps to solve the above problems and improve the wetting effect of the electrolyte.

[0175] For example, the first straight groove 101 extends along the width direction X. Among the capillary recesses 100 located in the same row, the distance between the second straight groove 102 of one capillary recess 100 and the third straight groove 103 of another capillary recess 100 is the minimum distance D between adjacent capillary recesses 100.

[0176] For example, in the capillary recesses 100 located in the same row, each capillary recess 100 is equally spaced.

[0177] In some feasible ways, in at least some rows of capillary recesses 100, the second straight groove 102 and the third straight groove 103 of any capillary recess 100 in any row are respectively connected to the first straight groove 101 of two capillary recesses 100 in the adjacent row.

[0178] See Figure 6 As shown, in all rows of capillary recesses 100, the second straight groove 102 and the third straight groove 103 of any capillary recess 100 in any row are respectively connected to the first straight groove 101 of two capillary recesses 100 in the adjacent row. In any two adjacent rows of capillary recesses 100, the second straight groove 102 of any capillary recess 100 in one row is connected to the first straight groove 101 of a capillary recess 100 in the other row, and the third straight groove 103 of any capillary recess 100 in one row is connected to the first straight groove 101 of a capillary recess 100 in the other row.

[0179] In a row, the second straight groove 102 and the third straight groove 103 of any capillary recess 100 are connected to a capillary recess 100. Two capillary recesses 100 connected to the second straight groove 102 and the third straight groove 103 of the same capillary recess 100 are located in the same row.

[0180] Electrolyte drawn into one capillary recess 100 in a row can flow into two different capillary recesses 100 in the next row through the second straight channel 102 and the third straight channel 103, respectively. Alternatively, electrolyte drawn into two capillary recesses 100 in a row can flow into one capillary recess 100 in another row through the second straight channel 102 and the third straight channel 103, respectively.

[0181] In any two adjacent rows of capillary recesses 100, there are relatively more flow branches formed between the capillary recesses 100 in one row and the capillary recesses 100 in the other row, which allows the electrolyte to flow in more directions and areas along different capillary recesses 100, which is beneficial to improving the wetting rate and wetting effect of the electrolyte on different areas of the electrode 70.

[0182] In some examples, the capillary recesses 100 in each row are not connected. In each row, no two adjacent capillary recesses 100 are connected. Within the same row, each capillary recess 100 is independently configured.

[0183] After the capillary recesses 100 near the edge of the active material layer 90 absorb the electrolyte, the electrolyte can flow down to the next row of capillary recesses 100 along the direction from the edge of the active material layer 90 to the middle region. The electrolyte can flow along the interconnected capillary recesses 100 in the width direction X, which is beneficial to improve the wetting rate and wetting effect of the electrolyte in the width direction X towards the middle region of the active material layer 90.

[0184] See in some examples Figures 20 to 23 As shown, the active material layer 90 also includes a liquid storage portion 110. The liquid storage portion 110 has an opening facing away from the current collector 80. Along the width direction X, capillary recesses 100 are provided between the liquid storage portion 110 and the edge of the active material layer 90. In a row of capillary recesses 100 near the liquid storage portion 110, at least one of the second straight groove 102 and the third straight groove 103 of any one capillary recess 100 is provided with a liquid storage portion 110.

[0185] For example, in a row of capillary recesses 100 near the liquid storage section 110, the second straight groove 102 of any one capillary recess 100 is provided with a corresponding liquid storage section 110.

[0186] For example, in a row of capillary recesses 100 near the liquid storage section 110, the third straight groove 103 of any one capillary recess 100 is provided with a corresponding liquid storage section 110.

[0187] For example, in a row of capillary recesses 100 near the liquid storage section 110, the second straight groove 102 and the third straight groove 103 of any one capillary recess 100 are respectively provided with a liquid storage section 110. For instance, in a row of capillary recesses 100 near the liquid storage section 110, the second straight groove 102 and the third straight groove 103 of any one capillary recess 100 are each provided with a liquid storage section 110. Alternatively, in a row of capillary recesses 100 near the liquid storage section 110, the second straight groove 102 and the third straight groove 103 of any one capillary recess 100 are connected to a liquid storage section 110.

[0188] The liquid storage section 110 has the function of storing and retaining liquid. After the electrolyte flows into the liquid storage section 110 along the capillary recess 100, the electrolyte can be stored in the liquid storage section 110.

[0189] During charging and discharging cycles, the electrode assembly 60 of the battery cell 30 expands and contracts. During this expansion and contraction, the electrolyte stored in the electrolyte reservoir 110 is less likely to be squeezed out of the electrode assembly 60, ensuring that the electrolyte in the electrolyte reservoir 110 can still wet the surrounding area. This improves the wetting effect of the electrolyte and reduces the possibility of lithium plating due to a lack of electrolyte in local areas of the electrode 70.

[0190] See also some of the possible implementation methods. Figure 20 and Figure 21 As shown, the liquid storage section 110 includes a connecting straight groove 111 and a plurality of branch straight grooves 112. The end of each branch straight groove 112 communicates with the end of the connecting straight groove 111 to form a third communication point 400. In a row of capillary recesses 100 near the liquid storage section 110, at least one of the second straight groove 102 and the third straight groove 103 of any one capillary recess 100 communicates with the corresponding liquid storage section 110 through the connecting straight groove 111.

[0191] For example, in a row of capillary recesses 100 near the liquid storage section 110, the second straight groove 102 of any one of the capillary recesses 100 is connected to the corresponding liquid storage section 110 through a connecting straight groove 111.

[0192] For example, in a row of capillary recesses 100 near the liquid storage section 110, the third straight groove 103 of any one capillary recess 100 is connected to the corresponding liquid storage section 110 through a connecting straight groove 111.

[0193] For example, in a row of capillary recesses 100 near the liquid storage section 110, the second straight groove 102 and the third straight groove 103 of any one capillary recess 100 are each connected to the corresponding liquid storage section 110 through a connecting straight groove 111.

[0194] Electrolyte in a row of capillary recesses 100 near the reservoir 110 flows into the reservoir 110 through corresponding connecting straight channels 111. The electrolyte flows within the connecting straight channels 111 and then to each branch straight channel 112. The branch straight channels 112 have a liquid storage and retention function. After the electrolyte flows into the branch straight channels 112, the branch straight channels 112 can store the electrolyte, so that the reservoir 110 has good liquid storage capacity.

[0195] For example, multiple liquid storage sections 110 may be located in the same row. The liquid storage sections 110 located in the same row are not interconnected, and each liquid storage section 110 is set independently.

[0196] For example, one end of a connecting straight groove 111 may be provided with more than three branch straight grooves 112.

[0197] For example, the included angle between the branch straight groove 112 and the connecting straight groove 111 is greater than 90°. Along the width direction X, the end of the connecting straight groove 111 furthest from the third connection point 400 is near one edge of the active material layer 90, and the end of the branch straight groove 112 furthest from the third connection point 400 is near another edge of the active material layer 90. The included angle between any two adjacent branch straight grooves 112 is less than 90°. For example, the included angle between any two adjacent branch straight grooves 112 ranges from 15° to 30°.

[0198] For example, the connecting straight groove 111 extends along the width direction X. The angle between each branch straight groove 112 and the width direction X is an acute angle.

[0199] For example, there is a gap between the connecting groove 111 and the surface of the active material layer 90 facing the current collector 80. The connecting groove 111 does not penetrate the active material layer 90.

[0200] For example, there is a gap between the branched straight groove 112 and the surface of the active material layer 90 facing the current collector 80. The branched straight groove 112 does not penetrate the active material layer 90.

[0201] See also some of the possible implementation methods. Figure 22 and Figure 23 As shown, the liquid storage section 110 includes a connecting straight groove 111, a communicating groove 113, and a liquid storage recess 114. Three or more liquid storage recesses 114 are spaced apart. Any two liquid storage recesses 114 are connected by the communicating groove 113, and the communicating groove 113 and the liquid storage recess 114 are connected to form an annular structure 110a. The communicating groove 113 or the liquid storage recess 114 is connected to the connecting straight groove 111.

[0202] In a row of capillary recesses 100 near the liquid storage section 110, at least one of the second straight groove 102 and the third straight groove 103 of any one capillary recess 100 is connected to the corresponding liquid storage section 110 through a connecting straight groove 111.

[0203] For example, in a row of capillary recesses 100 near the liquid storage section 110, the second straight groove 102 of any one of the capillary recesses 100 is connected to the liquid storage section 110 through a connecting straight groove 111.

[0204] For example, in a row of capillary recesses 100 near the liquid storage section 110, the third straight groove 103 of any one capillary recess 100 is connected to the liquid storage section 110 through a connecting straight groove 111.

[0205] For example, in a row of capillary recesses 100 near the liquid storage section 110, the second straight groove 102 and the third straight groove 103 of any one capillary recess 100 are each connected to the liquid storage section 110 through a connecting straight groove 111.

[0206] Electrolyte in a row of capillary recesses 100 near the reservoir 110 can flow into the reservoir 110 through corresponding connecting straight channels 111. The electrolyte flows within the connecting straight channels 111 and then to the various connecting channels 113 and reservoir recesses 114 in the annular structure 110a. The reservoir recesses 114 have the function of storing and retaining electrolyte. After the electrolyte flows into the reservoir recesses 114, the reservoir recesses 114 can store the electrolyte, so that the reservoir 110 has good electrolyte storage capacity.

[0207] When the electrolyte in any of the storage recesses 114 is insufficient, the electrolyte in other adjacent storage recesses 114 can be replenished to the storage recesses 114 that are lacking electrolyte through the connecting channel 113, so that each storage recess 114 stores electrolyte, thereby reducing the possibility of lithium plating problems in the area where the storage recess 114 is located and the surrounding area due to the lack of electrolyte in a number of storage recesses 114.

[0208] For example, the connecting channel 113 can be a straight channel, which helps to reduce the flow resistance of the electrolyte.

[0209] For example, there is a gap between the connecting groove 113 and the surface of the active material layer 90 facing the current collector 80. The connecting groove 113 does not penetrate the active material layer 90.

[0210] For example, the liquid storage recess 114 can be a hemispherical recess. For example, the opening diameter of the liquid storage recess 114 ranges from 4 micrometers to 7 micrometers. For example, the opening diameter of the liquid storage recess 114 is 4 micrometers, 5 micrometers, 6 micrometers, or 7 micrometers.

[0211] For example, there is a gap between the liquid storage recess 114 and the surface of the active material layer 90 facing the current collector 80. The liquid storage recess 114 does not penetrate the active material layer 90.

[0212] For example, the depth of the liquid storage recess 114 along the thickness direction Y of the current collector 80 ranges from 9 micrometers to 11 micrometers, so that the liquid storage recess 114 has good liquid storage capacity. For example, the depth of the liquid storage recess 114 is 9 micrometers, 10 micrometers, or 11 micrometers.

[0213] For example, multiple liquid storage sections 110 may be located in the same row. The liquid storage sections 110 located in the same row are not interconnected, and each liquid storage section 110 is set independently.

[0214] Exemplarily, the six connecting grooves 113 and the six liquid-retaining recesses 114 can form an annular structure 110a. For example, the six connecting grooves 113 and the six liquid-retaining recesses 114 form a hexagonal annular structure 110a. The six liquid-retaining recesses 114 are located at the six vertices of the annular structure 110a. A connecting groove 111 communicates with one of the liquid-retaining recesses 114.

[0215] See in some examples Figure 24 and Figure 25 As shown, each connecting groove 113 and each liquid storage recess 114 forms two or more annular structures 110a. The two or more annular structures 110a are interconnected.

[0216] The relatively large number of liquid storage recesses 114 in the two or more annular structures 110a allows the liquid storage section 110 to store a relatively large amount of electrolyte, and the electrolyte stored in the liquid storage section 110 can wet a relatively large area. The liquid storage recesses 114 in each annular structure 110a are interconnected, and each liquid storage recess 114 has the function of mutually replenishing electrolyte, which is beneficial to improving the liquid storage capacity of the liquid storage section 110.

[0217] For example, any two adjacent annular structures 110a can share a connecting groove 113 and two liquid storage recesses 114 at both ends of the connecting groove 113.

[0218] For example, two or more annular structures 110a are arranged in a direction perpendicular to the width direction X.

[0219] For example, a liquid reservoir 110 may include four annular structures 110a.

[0220] See in some examples Figure 24 and Figure 25As shown, each annular structure 110a is provided with a corresponding connecting straight groove 111. The number of annular structures 110a is equal to the number of connecting straight grooves 111. In a row of capillary recesses 100 near the liquid storage section 110, the second straight groove 102 and the third straight groove 103 of any capillary recess 100 are each connected to a connecting straight groove 111. The capillary recesses 100 can deliver electrolyte into the corresponding connecting straight grooves 111 through the second straight grooves 102 and the third straight grooves 103. The electrolyte can flow into each corresponding annular structure 110a through each connecting straight groove 111.

[0221] The one-to-one correspondence between the number of annular structures 110a and the number of connecting straight grooves 111 facilitates the flow of electrolyte into each annular structure 110a through each connecting straight groove 111 via a relatively short path. This reduces the possibility that electrolyte may fail to reach some of the storage recesses 114 in the annular structure 110a, resulting in a lack of electrolyte in some of the storage recesses 114.

[0222] For example, a liquid storage section 110 may include four annular structures 110a and four connecting straight grooves 111. The second straight groove 102 and the third straight groove 103 of each capillary recess 100 are respectively connected to one annular structure 110a. One capillary recess 100 is connected to two annular structures 110a. The four annular structures 110a are interconnected.

[0223] See also some of the possible implementation methods. Figure 24 and Figure 25 As shown, the active material layer 90 includes a first region 91 and a second region 92 arranged along the width direction X. Both the first region 91 and the second region 92 are provided with capillary recesses 100 and liquid storage portions 110.

[0224] External electrolyte can flow into the capillary recess 100 provided in the first region 91 and flow into the reservoir 110 of the first region 91. External electrolyte can also flow into the capillary recess 100 provided in the second region 92 and flow into the reservoir 110 of the second region 92. The electrolyte can enter the capillary recess 100 and the reservoir 110 from the two opposite edges of the active material layer 90 along the width direction X, which is beneficial to improving the wetting rate and wetting effect of the electrolyte.

[0225] In some examples, along the width direction X, the width of the first region 91 can be equal to the width of the second region 92.

[0226] See in some examples Figure 22 and Figure 24As shown, the capillary recess 100 and liquid storage portion 110 in the first region 91 and the capillary recess 100 and liquid storage portion 110 in the second region 92 are each independently provided. The capillary recess 100 and liquid storage portion 110 in the first region 91 and the capillary recess 100 in the second region 92 are not interconnected.

[0227] In some examples, the first region 91 is provided with multiple rows of capillary recesses 100. In all rows of capillary recesses 100 in the first region 91, any capillary recess 100 in any row is connected to the first straight groove 101 of the capillary recess 100 in the adjacent row through at least one of the second straight groove 102 and the third straight groove 103.

[0228] For example, see Figure 24 and Figure 25 As shown, in all rows of capillary recesses 100 in the first region 91, the second straight groove 102 and the third straight groove 103 of any capillary recess 100 in any row are respectively connected to the first straight groove 101 of two capillary recesses 100 in the adjacent row.

[0229] In some examples, the second region 92 is provided with multiple rows of capillary recesses 100. In all rows of capillary recesses 100 in the second region 92, any capillary recess 100 in any row is connected to the first straight groove 101 of the capillary recess 100 in the adjacent row through at least one of the second straight groove 102 and the third straight groove 103.

[0230] For example, see Figure 24 and Figure 25 As shown, in all rows of capillary recesses 100 in the second region 92, the second straight groove 102 and the third straight groove 103 of any capillary recess 100 in any row are respectively connected to the first straight groove 101 of two capillary recesses 100 in the adjacent row.

[0231] In some examples, the liquid storage section 110 provided in the first region 91 and the liquid storage section 110 provided in the second region 92 are both located in the middle region of the active material layer 90, which is beneficial to improving the wetting effect of the electrolyte on the middle region.

[0232] In some examples, there is a gap between the liquid storage section 110 provided in the first region 91 and the liquid storage section 110 provided in the second region 92 along the width direction X.

[0233] In some examples, the capillary recesses 100 of the first region 91 and the capillary recesses 100 of the second region 92 are symmetrically or alternately arranged. The liquid storage portions 110 of the first region 91 and the liquid storage portions 110 of the second region 92 are symmetrically or alternately arranged.

[0234] For example, see Figure 20 or Figure 22 As shown, the capillary recesses 100 of the first region 91 and the capillary recesses 100 of the second region 92 are staggered. The staggered arrangement means that the capillary recesses 100 of the first region 91 and the capillary recesses 100 of the second region 92 are offset from each other.

[0235] The liquid storage section 110 in the first region 91 and the liquid storage section 110 in the second region 92 are arranged alternately. The alternate arrangement means that the positions of the liquid storage section 110 in the first region 91 and the liquid storage section 110 in the second region 92 are offset from each other.

[0236] The electrolyte can wet different regions of the electrode 70 through the capillary recess 100 and the liquid storage portion 110 of the first region 91 and the capillary recess 100 and the liquid storage portion 110 of the second region 92, thereby improving the wetting effect of the electrolyte.

[0237] For example, see Figure 24 As shown, the capillary recesses 100 in the first region 91 and the capillary recesses 100 in the second region 92 are symmetrically arranged. The liquid storage portions 110 in the first region 91 and the liquid storage portions 110 in the second region 92 are symmetrically arranged.

[0238] The capillary recesses 100 in the first region 91 and the capillary recesses 100 in the second region 92 are mirror images of each other, so that the capillary recesses 100 in the first region 91 and the capillary recesses 100 in the second region 92 have similar or identical performance in guiding electrolyte flow, which is beneficial to improving the consistency of electrolyte wetting effect in the first region 91 and the second region 92.

[0239] The liquid storage section 110 of the first region 91 and the liquid storage section 110 of the second region 92 are mirror images of each other, so that the liquid storage and retention performance of the liquid storage section 110 of the first region 91 and the liquid storage section 110 of the second region 92 are similar or the same, which is beneficial to improving the consistency of electrolyte wetting effect in the first region 91 and the second region 92.

[0240] For example, the capillary recesses 100 of the first region 91 and the capillary recesses 100 of the second region 92 are symmetrically arranged. The liquid storage portions 110 of the first region 91 and the liquid storage portions 110 of the second region 92 are staggered.

[0241] For example, the capillary recesses 100 of the first region 91 and the capillary recesses 100 of the second region 92 are alternately arranged. The liquid storage portions 110 of the first region 91 and the liquid storage portions 110 of the second region 92 are symmetrically arranged.

[0242] In some examples, the active material layer 90 includes a first region 91 and a second region 92 arranged along the width direction X. Both the first region 91 and the second region 92 are provided with capillary recesses 100. The capillary recesses 100 of the first region 91 and the capillary recesses 100 of the second region 92 are arranged symmetrically or alternately.

[0243] See Figure 26 and Figure 27 As shown, the capillary recesses 100 in the first region 91 and the capillary recesses 100 in the second region 92 are symmetrically arranged. The structures and positions of the capillary recesses 100 in the first region 91 and the capillary recesses 100 in the second region 92 are mirror images of each other, so that the performance of the capillary recesses 100 in the first region 91 and the capillary recesses 100 in the second region 92 in guiding electrolyte flow is similar or the same, which is beneficial to improving the consistency of electrolyte wetting effect in the first region 91 and the second region 92.

[0244] See Figure 28 As shown, the capillary recesses 100 of the first region 91 and the capillary recesses 100 of the second region 92 are alternately arranged. The electrolyte can wet different regions of the electrode 70 through the capillary recesses 100 of the first region 91 and the capillary recesses 100 of the second region 92 respectively, thereby improving the wetting effect of the electrolyte.

[0245] See in some examples Figure 26 and Figure 28 As shown, the capillary recess 100 provided in the first region 91 and the capillary recess 100 provided in the second region 92 are not connected to each other.

[0246] See also some of the possible implementation methods. Figure 29 As shown, along the width direction X and from the edge of the active material layer 90 to the middle region, the number of capillary recesses 100 in each row increases.

[0247] The closer to the edge of the active material layer 90, the fewer the number of capillary recesses 100. This allows the electrolyte flowing into the capillary recesses 100 to flow relatively quickly into the next row of capillary recesses 100, which is beneficial for improving the electrolyte wetting rate. The closer to the middle region of the active material layer 90, the more capillary recesses 100 there are. This results in more pathways for the electrolyte to flow, allowing it to flow in more directions and areas along different capillary recesses 100. This is beneficial for improving the wetting rate and wetting effect of the electrolyte on different areas of the electrode 70.

[0248] See also some of the possible implementation methods. Figure 29 and Figure 30As shown, along the width direction X and from the edge of the active material layer 90 to the middle region, the included angle K between the second straight groove 102 and the third straight groove 103 of the capillary recess 100 decreases.

[0249] The smaller the included angle K between the second straight groove 102 and the third straight groove 103 of the capillary recess 100, the larger the included angle between the second straight groove 102 and the third straight groove 103 and the first straight groove 101. During the process of the electrolyte flowing from the first straight groove 101 into the second straight groove 102 or the third straight groove 103, or vice versa, the smaller the angle at which the electrolyte changes direction, the better it reduces the flow resistance of the electrolyte and increases the rate at which the electrolyte wets the capillary recess 100.

[0250] Along the width direction X and from the edge of the active material layer 90 to the middle region, the included angle K between the second straight groove 102 and the third straight groove 103 of the capillary recess 100 becomes smaller, which reduces the flow resistance of the electrolyte during the flow process from the edge of the active material layer 90 to the middle region. This is beneficial to increasing the wetting rate of the electrolyte climbing from the edge of the active material layer 90 to the middle region of the active material layer 90, and at the same time, it is beneficial to realize the electrolyte climbing to the middle region of the active material layer 90, thereby improving the wetting effect on the middle region.

[0251] In some examples, along the width direction X and from the edge of the active material layer 90 to the middle region, the included angle K between the second straight groove 102 and the third straight groove 103 of the capillary recess 100 decreases linearly. For example, in any two adjacent rows of capillary recesses 100, the angle between the second straight groove 102 and the third straight groove 103 of the capillary recesses 100 in the row closer to the edge of the active material layer 90 and the angle between the second straight groove 102 and the third straight groove 103 of the capillary recesses 100 in the row closer to the middle region of the active material layer 90 differs by 1°.

[0252] In some examples, the included angle K between the second straight groove 102 and the third straight groove 103 of the capillary recess 100 ranges from 30° to 45°. For example, the included angle K between the second straight groove 102 and the third straight groove 103 of the capillary recess 100 can be 30°, 35°, 40°, or 45°.

[0253] In some feasible ways, the depth of the capillary recess 100 gradually decreases along the width direction X and from the edge of the active material layer 90 to the middle region.

[0254] The smaller the depth of the capillary recess 100, the smaller the cross-sectional area of ​​the capillary recess 100, which makes the capillary force on the electrolyte relatively greater. This is beneficial to increasing the wetting rate of the electrolyte climbing from the edge of the active material layer 90 to the middle region of the active material layer 90, and at the same time, it is beneficial to enable the electrolyte to climb to the middle region of the active material layer 90, thereby improving the wetting effect on the middle region.

[0255] In some examples, the depth of the capillary recess 100 ranges from 10 micrometers to 60 micrometers.

[0256] See also some of the possible implementation methods. Figure 31 As shown, there is a gap between the capillary recess 100 and the surface of the active material layer 90 facing the current collector 80. Along the thickness direction Y of the current collector 80, the capillary recess 100 does not penetrate the active material layer 90.

[0257] If the capillary recess 100 penetrates the active material layer 90, on the one hand, there is a possibility that the overall tensile strength of the electrode 70 will decrease, affecting the overall mechanical strength of the electrode 70, and causing cracks or fractures in the area of ​​the current collector 80 corresponding to the capillary recess 100; on the other hand, when the capillary recess 100 is processed by etching, it is easy to etch the current collector 80, affecting the structural strength of the current collector 80 itself or generating metal debris, which may cause a short circuit between the positive and negative electrode plates through the metal debris.

[0258] In some examples, the distance between the capillary recess 100 and the surface of the active material layer 90 facing the current collector 80 is greater than 40 micrometers.

[0259] See in some examples Figure 31 As shown, active material layers 90 are respectively provided on both sides of the current collector 80 along the thickness direction Y. The sum of the depths of the capillary recesses 100 provided on each of the two active material layers 90 is less than 1 / 4 of the overall thickness of the electrode 70, thereby ensuring that the overall mechanical strength of the electrode 70 meets the product requirements and reducing the possibility of a decrease in the overall tensile strength of the electrode 70 due to an excessively large sum of the depths of the capillary recesses 100.

[0260] Along the thickness direction Y of the current collector 80, the current collector 80 has two opposing surfaces. An active material layer 90 is disposed on each of the two surfaces of the current collector 80.

[0261] For example, along the thickness direction Y of the current collector 80, the capillary recesses 100 on one side of the current collector 80 are arranged alternately or symmetrically with the capillary recesses 100 on the other side.

[0262] In some feasible implementations, electrode 70 is a negative electrode. Capillary recesses 100 are provided on the negative electrode active material layer 90. The material of the negative electrode active material layer 90 includes carbon or silicon; therefore, providing capillary recesses 100 on the negative electrode active material layer 90 results in less capacity loss in the battery cell 30.

[0263] According to some embodiments of this application, this application also provides an electrode assembly 60, which includes the electrode 70 of any of the above embodiments.

[0264] See also some of the possible implementation methods. Figure 31 As shown, the electrode assembly 60 also includes a spacer 120. An inorganic material film 130 is disposed on the surface of the spacer 120 facing the electrode 70. The electrode 70 and the spacer 120 with the inorganic material film 130 are wound to form the electrode assembly 60 using a winding process. The inorganic material film 130 has capillary channels. The openings of the capillary recesses 100 are disposed facing the inorganic material film 130.

[0265] The capillary channels of the inorganic material film 130 can guide the electrolyte to flow from the edge of the electrode 70 to the inside of the electrode 70 through capillary forces. The inorganic material film 130 and the corresponding capillary recesses 100 can work together to guide the electrolyte to flow from the edge of the electrode 70 to the inside of the electrode 70 through capillary forces, thereby increasing the electrolyte wetting rate and improving the electrolyte wetting effect.

[0266] In some examples, the inorganic material film 130 may include a ceramic coating solution (CCS). The inorganic material film 130 may include alumina. Exemplarily, an inorganic ceramic material including alumina and other additives such as binders and solvents is formulated into a ceramic slurry and coated on one or both sides of the spacer 120 by a coating method such as casting or dip coating to form the inorganic material film 130.

[0267] According to some embodiments of this application, this application also provides a battery cell 30, including the electrode assembly 60 of any of the above embodiments.

[0268] According to some embodiments of this application, this application also provides a battery device 10, including a battery cell 30 of any of the above embodiments.

[0269] According to some embodiments of this application, this application also provides an electrical device including the battery device 10 of any of the above embodiments, and the battery device 10 is used to provide electrical energy to the electrical device. The electrical device can be any of the aforementioned devices or systems that utilize the battery device 10.

[0270] 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: The shell has a receiving cavity; An electrode assembly is disposed within the receiving cavity. The electrode assembly includes an electrode sheet, which includes a current collector and an active material layer disposed on at least one surface of the current collector. The active material layer includes capillary recesses, and multiple rows of the capillary recesses are disposed along the width direction of the current collector. Each capillary recess has an opening facing away from the current collector. The capillary recess includes a first straight groove, a second straight groove, and a third straight groove. One end of each of the first, second, and third straight grooves is interconnected to form a first connection point. The angles between the second and third straight grooves and the first straight groove are obtuse angles. In at least some of the rows of capillary recesses, any one of the capillary recesses in any row is connected to the first straight groove of the capillary recess in the adjacent row through at least one of the second straight groove and the third straight groove.

2. The battery cell according to claim 1, characterized in that, Along the width direction and from the edge of the active material layer to the middle region, the number of capillary recesses in each row increases.

3. The battery cell according to claim 1 or 2, characterized in that, Along the width direction and from the edge of the active material layer to the middle region, the included angle between the second straight groove and the third straight groove of the capillary recess decreases.

4. The battery cell according to claim 3, characterized in that, The included angle between the second straight groove and the third straight groove of the capillary recess ranges from 30° to 45°.

5. The battery cell according to any one of claims 1 to 4, characterized in that, Along the width direction and from the edge of the active material layer to the middle region, the depth of the capillary recess gradually decreases.

6. The battery cell according to any one of claims 1 to 5, characterized in that, There is a gap between the capillary recess and the surface of the active material layer facing the current collector.

7. The battery cell according to claim 6, characterized in that, Along the thickness direction of the current collector, active material layers are respectively provided on both sides of the current collector, and the sum of the depths of the capillary recesses provided on each of the two active material layers is less than 1 / 4 of the overall thickness of the electrode.

8. The battery cell according to any one of claims 1 to 7, characterized in that, The electrode includes a tab, which is connected to the current collector, and the extension direction of the tab is the same as the width direction of the current collector.

9. The battery cell according to any one of claims 1 to 8, characterized in that, At least one row of capillary recesses includes a plurality of interconnected capillary recesses, wherein the second straight groove of one of the interconnected capillary recesses is connected to the third straight groove of another to form a second connection point. The second connection point is connected to the first straight groove of the capillary recess in the other row.

10. The battery cell according to any one of claims 1 to 8, characterized in that, The capillary recesses in each row are not interconnected. In at least some of the rows of capillary recesses, any one of the capillary recesses in any row is connected to the first straight groove of a capillary recess in an adjacent row via the second straight groove or the third straight groove.

11. The battery cell according to claim 10, characterized in that, Three or more rows of capillary recesses are provided along the width direction. In a series of capillary recesses, the first straight groove of the Mth capillary recess is connected to the third straight groove of the (M-1)th capillary recess, where M is an even number; the first straight groove of the Nth capillary recess is connected to the second straight groove of the (N-1)th capillary recess, where N is an odd number greater than 1; or, In a series of capillary recesses, the first straight groove of the Mth capillary recess is connected to the second straight groove of the (M-1)th capillary recess, where M is an even number; the first straight groove of the Nth capillary recess is connected to the third straight groove of the (N-1)th capillary recess, where N is an odd number greater than 1.

12. The battery cell according to any one of claims 1 to 8, characterized in that, In at least some of the rows of capillary recesses, the second straight groove and the third straight groove of any one of the capillary recesses in any row are respectively connected to the first straight grooves of two capillary recesses in an adjacent row.

13. The battery cell according to claim 12, characterized in that, The capillary recesses in each row are not connected.

14. The battery cell according to claim 10 or 13, characterized in that, In each row of capillary recesses, the minimum distance between any two adjacent capillary recesses is greater than 1.5 mm and less than 4 mm.

15. The battery cell according to any one of claims 1 to 14, characterized in that, The active material layer further includes a liquid storage portion, and along the width direction, the capillary recess is disposed between the liquid storage portion and the edge of the active material layer. In a row of capillary recesses near the liquid storage section, at least one of the second straight groove and the third straight groove of any one of the capillary recesses is provided with the liquid storage section.

16. The battery cell according to claim 15, characterized in that, The liquid storage section includes a connecting straight channel and multiple branch straight channels, with the end of each branch straight channel connected to the end of the connecting straight channel to form a third connection point. In a row of capillary recesses near the liquid storage section, at least one of the second straight groove and the third straight groove of any one of the capillary recesses is connected to the corresponding liquid storage section through the connecting straight groove.

17. The battery cell according to claim 15, characterized in that, The liquid storage section includes a connecting straight groove, a communicating groove, and a liquid storage recess. Three or more liquid storage recesses are spaced apart. Any two liquid storage recesses are connected by the communicating groove, and the communicating groove and the liquid storage recess are connected to form a ring structure. The communicating groove or the liquid storage recess is connected to the connecting straight groove. In a row of capillary recesses near the liquid storage section, at least one of the second straight groove and the third straight groove of any one of the capillary recesses is connected to the corresponding liquid storage section through the connecting straight groove.

18. The battery cell according to claim 17, characterized in that, Each of the connecting grooves and each of the liquid storage recesses forms two or more of the annular structures.

19. The battery cell according to claim 18, characterized in that, Each of the annular structures is provided with a corresponding connecting straight groove. In the row of capillary recesses near the liquid storage section, the second straight groove and the third straight groove of any one of the capillary recesses are each connected to a connecting straight groove.

20. The battery cell according to any one of claims 15 to 19, characterized in that, The active material layer includes a first region and a second region arranged along the width direction, and both the first region and the second region are provided with capillary recesses and liquid storage portions.

21. The battery cell according to claim 20, characterized in that, The capillary recesses in the first region and the capillary recesses in the second region are symmetrically or alternately arranged, and the liquid storage portions in the first region and the liquid storage portions in the second region are symmetrically or alternately arranged.

22. The battery cell according to claim 20 or 21, characterized in that, The capillary recess and the liquid storage portion in the first region are not connected to each other with the capillary recess in the second region.

23. The battery cell according to any one of claims 1 to 19, characterized in that, The active material layer includes a first region and a second region arranged along the width direction. Both the first region and the second region are provided with capillary recesses. The capillary recesses in the first region and the capillary recesses in the second region are arranged symmetrically or alternately.

24. The battery cell according to claim 23, characterized in that, The capillary recesses in the first region and the capillary recesses in the second region are not connected to each other.

25. The battery cell according to any one of claims 1 to 24, characterized in that, The electrode assembly further includes an isolator, on the surface of the isolator facing the electrode sheet, an inorganic material film layer is disposed, the inorganic material film layer has capillary channels, and the opening of the capillary recess is disposed facing the inorganic material film layer.

26. A battery device, characterized in that, Includes the battery cell as described in any one of claims 1 to 25.

27. An electrical appliance, characterized in that, Includes the battery device as described in claim 26, the battery device being used to provide electrical energy.

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