Battery cell, manufacturing method for battery cell, battery device, and electric device

Abstract

A battery cell (7), a manufacturing method for a battery cell (7), a battery device (2), and an electric device. Each electrode sheet (731) in an electrode assembly (73) of the battery cell (7) comprises a current collector (7311), an active material layer (7312), a connecting layer (7313), and a solid electrolyte layer (7314) that are sequentially stacked; a recess region (73131) is provided on the surface of the connecting layer (7313) facing away from the active material layer (7312); the recess region (73131) is provided with inwardly recessed recesses (73132); the solid electrolyte layer (7314) is provided on the surface of the connecting layer (7313) facing away from the active material layer (7312) and covers the recess region (73131); and a part of the solid electrolyte layer (7314) enters the recesses (73132) and is connected to the inner walls of the recesses (73132). Since a part of the solid electrolyte layer (7314) enters the recesses (73132) and is connected to the inner walls of the recesses (73132), the solid electrolyte layer (7314) in the recess region (73131) has a large thickness, and the solid electrolyte layer (7314) in the recess region (73131) also has a large contact area with the connecting layer (7313), so that the solid electrolyte layer (7314) is less prone to detachment, thereby reducing the risk of failure of the solid electrolyte layer (7314) due to a small thickness or detachment. Thus, two adjacent electrode sheets (731) are not prone to short-circuiting caused by overlapping, thereby improving the reliability of the battery cell (7).

Description

Battery cells, manufacturing methods of battery cells, battery devices and electrical devices Cross-references to related applications

[0001] This application claims priority to Chinese Patent Application No. 202510103893.0, filed on January 22, 2025, entitled “Battery cell, method of manufacturing battery cell, battery device and power consumption device”, the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of battery technology, and in particular to a battery cell, a method for manufacturing the battery cell, a battery device, and an electrical device. Background Technology

[0003] Battery devices have advantages such as high specific energy and high power density, and are widely used in electronic devices and transportation vehicles, such as mobile phones, laptops, electric vehicles, electric cars, electric airplanes, electric ships and power tools.

[0004] With the continuous development of the battery industry, how to improve the reliability of battery devices has attracted increasing attention from those skilled in the art. Summary of the Invention

[0005] In view of the above problems, this application provides a battery cell, a method for manufacturing the battery cell, a battery device, and an electrical device, wherein the battery cell has good reliability.

[0006] In a first aspect, some embodiments of this application provide a battery cell, which includes a casing and an electrode assembly. The casing forms a cavity, and the electrode assembly is disposed in the cavity. The electrode assembly includes stacked electrode sheets, each of which includes a current collector, an active material layer, a connecting layer, and a solid electrolyte layer. The active material layer is disposed on the surface of the current collector, and the connecting layer is disposed on the surface of the active material layer away from the current collector. The surface of the connecting layer away from the active material layer has a groove region, and the groove region has an inwardly recessed groove. The solid electrolyte layer is disposed on the surface of the connecting layer away from the active material layer and covers the groove region. A portion of the solid electrolyte layer enters the groove and is connected to the inner wall of the groove.

[0007] In the above structure, since the surface of the connecting layer away from the active material layer has a grooved area, and the solid electrolyte layer is disposed on the surface of the connecting layer with the grooved area, part of the solid electrolyte layer enters the groove and connects to the inner wall of the groove, not only does the solid electrolyte layer in the grooved area have a large thickness, but it also makes the solid electrolyte layer in the grooved area and the connecting layer have a large contact area, making the solid electrolyte layer less likely to fall off, reducing the possibility of failure due to insufficient thickness or falling off of the solid electrolyte layer, and making it less likely for adjacent electrodes to overlap and short-circuit, which is beneficial to improving the reliability of the battery cell.

[0008] According to some embodiments of this application, the current collector includes a blank area and a coated area disposed along a first direction. The coated area is provided with an active material layer, while the blank area is not provided with an active material layer. The connecting layer includes two end faces disposed opposite to each other along the first direction. The end faces are connected to the surface of the connecting layer away from the active material layer. The groove area includes two sub-regions, which are respectively connected to the two end faces, such that the two sub-regions are respectively connected to the two opposite edges of the connecting layer in the first direction, and the connecting layer is provided with grooves at the two opposite edges in the first direction.

[0009] According to some embodiments of the present application, the battery cell has two sub-regions spaced apart along a first direction, such that the area between the two sub-regions is a region without grooves. This means that the surface of the connecting layer away from the active material layer does not have grooves in the middle region of the first direction, which helps to reduce the area of ​​the grooved region. Since grooves need to be machined into the grooved region, reducing the area of ​​the grooved region helps to reduce the amount of processing work and lower the production cost of the electrode.

[0010] According to some embodiments of this application, in a battery cell, two sub-regions are connected in a first direction. By connecting the two sub-regions in the first direction, the groove area formed by the two sub-regions can cover the entire surface of the connecting layer away from the active material layer, so that the entire surface of the connecting layer away from the active material layer is provided with grooves. This is beneficial to increasing the thickness of the entire active material layer provided on the surface of the connecting layer away from the active material layer, making it less likely for adjacent electrodes to overlap and short-circuit, and improving the reliability of the battery cell.

[0011] According to some embodiments of the battery cell provided in this application, a sub-region penetrates the connecting layer along a second direction, which is perpendicular to the first direction. By setting the sub-region to penetrate the connecting layer along the second direction, the sub-region can be formed in the entire edge region of the surface of the connecting layer away from the active material layer in the first direction. This makes it less likely for the solid electrolyte slurry to flow away from the entire edge region of the surface of the connecting layer away from the active material layer, thus reducing the thickness of the solid electrolyte layer. This helps to reduce the possibility of failure of the solid electrolyte layer at the edge portion of the surface of the connecting layer away from the active material layer.

[0012] According to some embodiments of the present application, the area of ​​the groove region is set to A, and the area of ​​the surface of the connecting layer away from the active material layer is set to B, where A / B ≥ 10%. This ensures that the groove region occupies a sufficiently large proportion of the surface of the connecting layer away from the active material layer, and that the groove region sufficiently corresponds to the relatively thin solid electrolyte layer (mainly the edge region of the connecting layer in the first direction). This allows the solid electrolyte layer covering the connecting layer to be acted upon by a sufficiently large groove region, thereby increasing the thickness of the solid electrolyte layer in this region. This helps to reduce the possibility of short circuits caused by the overlap of adjacent electrodes and improves the reliability of the battery cell.

[0013] According to some embodiments of the present application, the battery cell has multiple grooves, which are spaced apart along a second direction to form a groove group. Multiple groove groups are also provided, spaced apart along a first direction, with the second direction perpendicular to the first direction. By including multiple grooves spaced apart along the second direction in the groove group, the groove group can be arranged through the surface of the connecting layer along the second direction. By providing multiple groove groups and spaced apart along the first direction, the groove area formed by the grooves has sufficient width in the first direction to function on a sufficiently wide solid electrolyte layer.

[0014] According to some embodiments of the battery cell provided in this application, the spacing between two adjacent grooves in the second direction is set to E, where 1μm≤E≤10000μm, and the spacing between two adjacent groove groups in the first direction is set to F, where 1μm≤F≤10000μm. By setting the spacing E between two adjacent grooves in the second direction to 1μm≤E≤10000μm, not only is the groove density in the second direction sufficient to act on the solid electrolyte layer, but the density of the grooves in the second direction is also prevented from being too large, thus avoiding high processing costs. By setting the spacing F between two adjacent groove groups in the first direction to 1μm≤F≤10000μm, not only is the groove group density in the first direction sufficient to act on the solid electrolyte layer, but the density of the groove group in the first direction is also prevented from being too large, thus avoiding high processing costs.

[0015] According to some embodiments of the present application, the cross-sectional shape of the groove is configured as at least one of a circle, triangle, rectangle or polygon, and the cross-section is parallel to the surface of the connecting layer away from the active material layer.

[0016] According to some embodiments of the battery cell provided in this application, the cross-sectional shape of the groove is configured as circular, and the diameter of the groove is set to G, where 1μm≤G≤10000μm. By setting the diameter G of the groove to the range of 1μm≤G≤10000μm, not only is the size of a single groove sufficient to allow the solid electrolyte slurry to enter, but the size of a single groove is also prevented from being too large and affecting the structural strength of the bonding layer.

[0017] According to some embodiments of this application, the battery cell has a groove that penetrates the connecting layer along the second direction. Multiple grooves are provided, and the multiple grooves are spaced apart along the first direction, so that the multiple grooves can effectively reduce the possibility of solid electrolyte slurry flowing into the blank area.

[0018] According to some embodiments of the present application, the spacing between two adjacent grooves in the first direction is set to D, where 1μm≤D≤10000μm. This not only ensures that the spacing between the grooves in the first direction is not too large, thus reducing the ability of the solid electrolyte slurry to flow into the blank area, but also ensures that the spacing between the grooves in the first direction is not too small, thus reducing the structural strength of the connecting layer.

[0019] According to some embodiments of the present application, the grooves in the battery cell are formed by laser etching or chemical etching.

[0020] According to some embodiments of the present application, the size of the groove along the thickness direction of the connecting layer is set to C, where 1μm≤C≤2000μm. This not only ensures that the groove has sufficient depth to accommodate the solid electrolyte layer, but also prevents the groove from damaging the structural strength of the connecting layer due to excessive depth.

[0021] According to some embodiments of this application, the battery cell has a diameter of 5μm ≤ C ≤ 500μm.

[0022] According to some embodiments of the present application, the interlayer peel strength between the solid electrolyte layer and the connecting layer of the battery cell is set to H, where 5N / m≤H≤10N / m. This not only makes the connection between the solid electrolyte layer and the connecting layer strong and prevents the solid electrolyte layer from falling off the connecting layer, making it less likely for adjacent electrodes to overlap and short-circuit, thus improving the reliability of the battery cell, but also ensures that the connection strength between the solid electrolyte layer and the connecting layer is not too high, which would make the electrode processing more difficult or more expensive.

[0023] Secondly, some embodiments of this application provide a method for manufacturing a single battery cell, the method comprising:

[0024] Provides a housing and a current collector with an active material layer on its surface;

[0025] A bonding slurry is coated on the surface of the active material layer facing away from the current collector and then dried to form a bonding layer;

[0026] Grooves are machined in the groove area on the surface of the connecting layer away from the active material layer;

[0027] A solid electrolyte slurry is coated on the surface of the connecting layer away from the active material layer and then dried to obtain an electrode with a solid electrolyte layer.

[0028] The electrodes are stacked and arranged to form an electrode assembly;

[0029] The electrode assembly is installed into the casing to form a battery cell.

[0030] According to some embodiments of this application, a method for manufacturing a battery cell includes a current collector comprising a blank area and a coating area disposed along a first direction. The coating area is provided with an active material layer, while the blank area is not provided with an active material layer. A connecting layer includes two end faces disposed opposite to each other along the first direction, the end faces being connected to the surface of the connecting layer away from the active material layer. A groove region includes two sub-regions, the two sub-regions being respectively connected to the two end faces. The step of forming a groove in the groove region on the surface of the connecting layer away from the active material layer includes:

[0031] Grooves are machined into the sub-region.

[0032] According to the battery cell manufacturing method provided in some embodiments of this application, grooves are processed by laser grooving or chemical etching.

[0033] Thirdly, some embodiments of this application provide a battery device that includes a battery cell provided by any of the above-described technical solutions.

[0034] Fourthly, some embodiments of this application provide an electrical device that includes a battery device provided by any of the above-described technical solutions, the battery device being used to provide electrical energy.

[0035] The technical solutions provided by the embodiments of this disclosure have at least the following beneficial effects:

[0036] Some embodiments of this application provide a battery cell, which includes a casing and an electrode assembly. The electrode assembly is disposed in a cavity formed by the casing. The electrode assembly includes stacked electrode sheets, each electrode sheet including a current collector, an active material layer, a connecting layer, and a solid electrolyte layer. The active material layer is disposed on the surface of the current collector. The connecting layer is disposed on the surface of the active material layer away from the current collector. The surface of the connecting layer away from the active material layer has a groove region with an inwardly recessed groove. The solid electrolyte layer is disposed on the surface of the connecting layer away from the active material layer and covers the groove region. A portion of the solid electrolyte layer enters the groove and is connected to the inner wall of the groove.

[0037] In the above structure, since the surface of the connecting layer away from the active material layer has a grooved area, and the solid electrolyte layer is disposed on the surface of the connecting layer with the grooved area, part of the solid electrolyte layer enters the groove and connects to the inner wall of the groove, not only does the solid electrolyte layer in the grooved area have a large thickness, but it also makes the solid electrolyte layer in the grooved area and the connecting layer have a large contact area, making the solid electrolyte layer less likely to fall off, reducing the possibility of failure due to insufficient thickness or falling off of the solid electrolyte layer, and making it less likely for adjacent electrodes to overlap and short-circuit, which is beneficial to improving the reliability of the battery cell.

[0038] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description

[0039] 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:

[0040] Figure 1 is a schematic diagram of the vehicle structure provided in some embodiments of this application;

[0041] Figure 2 is an exploded view of a battery device provided in some embodiments of this application;

[0042] Figure 3 is a split view of a battery cell provided in some embodiments of this application;

[0043] Figure 4 is a partial top view of the electrode structure provided in some embodiments of this application;

[0044] Figure 5 is a cross-sectional view of the electrode sheet provided in some embodiments of this application;

[0045] Figure 6 is a cross-sectional view of the electrode sheet provided in some other embodiments of this application;

[0046] Figure 7 is a cross-sectional view of the connecting layer in the electrode sheet provided in some embodiments of this application;

[0047] Figure 8 is a cross-sectional view of the connecting layer in the electrode provided in some other embodiments of this application;

[0048] Figure 9 is a flowchart of a method for manufacturing a battery cell provided in some other embodiments of this application.

[0049] In the picture:

[0050] 1. Vehicle; 2. Battery unit; 3. Controller; 4. Motor; 5. Housing; 5a. First housing section; 5b. Second housing section; 5c. Reception space; 7. Battery cell; 71. Shell; 72. Cavity; 73. Electrode assembly; 731. Electrode sheet; 7311. Current collector; 73111. Blank area; 73112. Coated area; 7312. Active material layer; 7313. Connecting layer; 73131. Groove area; 73132. Groove; 73133. Sub-area; 73134. Tank group; 7314. Solid electrolyte layer; X, First direction; Y, Second direction. Detailed Implementation

[0051] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0052] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used in the description of this application is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms "comprising" and "having," and any variations thereof, in the description, claims, and accompanying drawings of this application are intended to cover non-exclusive inclusion. The terms "first," "second," etc., in the description, claims, or accompanying drawings of this application are used to distinguish different objects, not to describe a specific order or hierarchy.

[0053] In this application, the reference to "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment that is mutually exclusive with other embodiments.

[0054] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "attachment" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0055] In this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, in this application, the character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0056] In the embodiments of this application, the same reference numerals denote the same components, and for the sake of brevity, detailed descriptions of the same components are omitted in different embodiments. It should be understood that the thickness, length, width, and other dimensions of various components in the embodiments of this application shown in the accompanying drawings, as well as the overall thickness, length, width, and other dimensions of the integrated device, are merely illustrative and should not constitute any limitation on this application.

[0057] In the embodiments of this application, "parallel" includes not only the case of absolute parallelism, but also the case of approximate parallelism as commonly understood in engineering; similarly, "perpendicular" also includes not only the case of absolute perpendicularity, but also the case of approximate perpendicularity as commonly understood in engineering. For example, if the angle between two directions is 85°-90°, the two directions can be considered perpendicular; if the angle between two directions is 0°-5°, the two directions can be considered parallel.

[0058] In this application, "multiple" means two or more (including two).

[0059] 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, among other fields.

[0060] The battery device mentioned in the embodiments of this application may include one or more battery cell assemblies for providing voltage and capacity. A battery cell assembly may include multiple battery cells, which are connected in series, parallel, or mixed connections via a busbar.

[0061] In some embodiments, a battery cell assembly is typically formed by arranging multiple battery cells; as an example, a battery cell assembly can be a battery module, which is formed by arranging and fixing multiple battery cells into a single module. As an example, a battery module can be formed by bundling multiple battery cells together with cable ties.

[0062] A battery cell can be a rechargeable battery cell, which refers to a battery cell that can be recharged after being discharged to activate the active materials and continue to be used.

[0063] Battery cells can be lithium-ion cells, sodium-ion cells, sodium-lithium-ion cells, lithium metal cells, sodium metal cells, lithium-sulfur cells, magnesium-ion cells, nickel-metal hydride cells, nickel-cadmium cells, lead-acid cells, etc.

[0064] A battery cell typically includes an electrode assembly and an electrolyte. The electrode assembly includes a positive electrode and a negative electrode. During the charging and discharging process of a battery cell, active ions (such as lithium ions) repeatedly insert and extract between the positive and negative electrodes. The electrolyte acts as a conductor of ions between the positive and negative electrodes. This application does not impose specific restrictions on the type of electrolyte; it can be selected according to requirements. The electrolyte can be liquid, gel, or solid.

[0065] A solid-state battery cell includes electrodes and a solid electrolyte. The electrodes are stacked to form an electrode assembly, and a solid electrolyte is placed between two adjacent electrodes to conduct ions between them.

[0066] The electrode assembly can be a wound structure, a stacked structure, or a hybrid structure of wound and stacked.

[0067] As an example, a battery cell can be a cylindrical battery cell, a prismatic battery cell, a pouch battery cell, or a battery cell of other shapes. Prismatic battery cells include prismatic battery cells, blade-shaped battery cells, and multi-prismatic batteries, such as hexagonal prismatic batteries.

[0068] In some embodiments, the battery device may be a battery pack, which includes a housing and one or more battery cell assemblies housed within the housing. As an example, the battery cell assembly may be a battery module, which can be housed within the housing by securing the battery module to the housing. Alternatively, the battery cell assembly may be housed within the housing by directly securing multiple battery cells to the housing.

[0069] In some embodiments, the housing may be part of the vehicle's chassis structure. For example, a portion of the housing may be at least a part of the vehicle's floor, or a portion of the housing may be at least a part of the vehicle's crossbeams and longitudinal beams.

[0070] In some embodiments, the battery device may be an energy storage device. Energy storage devices include energy storage containers, energy storage cabinets, etc.

[0071] With the rapid development of the battery industry, people have higher and higher requirements for the energy density of battery cells. The thickness of solid electrolytes has shown a trend of thinning, but this can easily lead to the failure of solid electrolytes and cause short circuits due to the overlap of adjacent electrodes, which is not conducive to improving the reliability of battery cells.

[0072] To improve the reliability of a single battery cell, some embodiments of this application provide a single battery cell including a casing and an electrode assembly. The electrode assembly is disposed in a cavity formed by the casing. The electrode assembly includes stacked electrode sheets, each including a current collector, an active material layer, a connecting layer, and a solid electrolyte layer. The active material layer is disposed on the surface of the current collector, and the connecting layer is disposed on the surface of the active material layer opposite to the current collector. The surface of the connecting layer opposite to the active material layer has a groove region with an inwardly recessed groove. The solid electrolyte layer is disposed on the surface of the connecting layer opposite to the active material layer and covers the groove region. A portion of the solid electrolyte layer enters the groove and is connected to the inner wall of the groove. In the above structure, since the surface of the connecting layer away from the active material layer has a grooved area, and the solid electrolyte layer is disposed on the surface of the connecting layer with the grooved area, part of the solid electrolyte layer enters the groove and connects to the inner wall of the groove, not only does the solid electrolyte layer in the grooved area have a large thickness, but it also makes the solid electrolyte layer in the grooved area and the connecting layer have a large contact area, making the solid electrolyte layer less likely to fall off, reducing the possibility of failure due to insufficient thickness or falling off of the solid electrolyte layer, and making it less likely for adjacent electrodes to overlap and short-circuit, which is beneficial to improving the reliability of the battery cell.

[0073] The battery cells described in the embodiments of this application are applicable to battery devices and electrical devices that use battery devices.

[0074] Electrical devices can include vehicles, mobile phones, portable devices, laptops, ships, spacecraft, electric toys, and power tools, etc. Vehicles can be gasoline-powered cars, natural gas-powered cars, or new energy vehicles; new energy vehicles can be pure electric vehicles, hybrid electric vehicles, or range-extended electric vehicles, etc. Spacecraft include airplanes, rockets, space shuttles, and spacecraft, etc. Electric toys include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc. Power tools include metal cutting power tools, grinding power tools, assembly power tools, and railway power tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers, etc. This application does not impose any special limitations on the above-mentioned electrical devices.

[0075] For ease of explanation, the following embodiments will use a vehicle as an example of an electrical device according to an embodiment of this application.

[0076] Figure 1 is a schematic diagram of the structure of a vehicle provided in some embodiments of this application.

[0077] As shown in Figure 1, a battery device 2 is installed inside the vehicle 1. The battery device 2 can be located at the bottom, front, or rear of the vehicle 1. The battery device 2 can be used to power the vehicle 1; for example, the battery device 2 can serve as the operating power source for the vehicle 1.

[0078] The vehicle 1 may also include a controller 3 and a motor 4. The controller 3 is used to control the battery device 2 to supply power to the motor 4, for example, for the power needs of the vehicle 1 during starting, navigation and driving.

[0079] In some embodiments of this application, the battery device 2 can not only serve as the operating power source for the vehicle 1, but also as the driving power source for the vehicle 1, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1.

[0080] Figure 2 is a schematic diagram showing the disassembled structure of a battery device provided in some embodiments of this application. As shown in Figure 2, the battery device 2 includes a housing 5 and battery cells 7, with the battery cells 7 housed within the housing 5. The battery cell 7 can be the smallest unit that makes up a battery.

[0081] The housing 5 is used to house the battery cell 7, and the housing 5 can have various structures. In some embodiments, the housing 5 may include a first housing portion 5a and a second housing portion 5b, which overlap each other, and together define a housing space 5c for housing the battery cell 7. The second housing portion 5b may be a hollow structure with one end open, and the first housing portion 5a may be a plate-like structure, with the first housing portion 5a covering the open side of the second housing portion 5b to form a housing 5 with the housing space 5c; alternatively, both the first housing portion 5a and the second housing portion 5b may be hollow structures with one side open, with the open side of the first housing portion 5a covering the open side of the second housing portion 5b to form a housing 5 with the housing space 5c. Of course, the first housing portion 5a and the second housing portion 5b can be various shapes, such as cylinders, cuboids, etc.

[0082] To improve the sealing performance after the first housing part 5a and the second housing part 5b are connected, a sealing element, such as sealant or sealing ring, can also be provided between the first housing part 5a and the second housing part 5b.

[0083] Assuming that the first box section 5a covers the top of the second box section 5b, the first box section 5a can also be called the upper box cover, and the second box section 5b can also be called the lower box.

[0084] In the battery device 2, there can be one or more battery cells 7. If there are multiple battery cells 7, they can be connected in series, in parallel, or in a mixed manner. A mixed connection means that multiple battery cells 7 are connected in both series and parallel. Multiple battery cells 7 can be directly connected in series, in parallel, or in a mixed manner, and then the whole assembly of multiple battery cells 7 is housed in the housing 5. Alternatively, multiple battery cells 7 can first be connected in series, in parallel, or in a mixed manner to form a battery module, and then multiple battery modules can be connected in series, in parallel, or in a mixed manner to form a whole assembly, which is then housed in the housing 5.

[0085] Some embodiments of this application provide a battery cell 7. Referring to FIG3, the battery cell 7 includes a housing 71 and an electrode assembly 73. The housing 71 forms a cavity 72, and the electrode assembly 73 is disposed in the cavity 72. The electrode assembly 73 includes stacked electrode sheets 731. The electrode sheet 731 includes a current collector 7311, an active material layer 7312, a connecting layer 7313, and a solid electrolyte layer 7314. The active material layer 7312 is disposed on the surface of the current collector 7311, and the connecting layer 7313 is disposed on the surface of the current collector 7311. The active material layer 7312 is disposed on the surface of the current collector 7311, and the connecting layer 7313 is disposed on the surface of the current collector 7311. The surface of the active material layer 7312 is away from the surface of the current collector 7311. Referring to Figures 4 and 5, the connecting layer 7313 is provided with a groove region 73131 away from the surface of the active material layer 7312. The groove region 73131 is provided with an inwardly recessed groove 73132. The solid electrolyte layer 7314 is disposed on the surface of the connecting layer 7313 away from the surface of the active material layer 7312 and covers the groove region 73131. A portion of the solid electrolyte layer 7314 enters the groove 73132 and is connected to the inner wall of the groove 73132.

[0086] The outer casing 71 can be a component within the battery cell 7 used to form a sealed cavity 72, which houses other components such as the electrode assembly 73 within the battery cell 7. The outer casing 71 can have various shapes and sizes, such as a cuboid or hexagonal prism. Specifically, the shape of the outer casing 71 can be determined based on the specific shape and size of the electrode assembly 73. The outer casing 71 can be made of various materials, such as copper, iron, aluminum, stainless steel, or aluminum alloy.

[0087] Electrode assembly 73 is a component in the battery cell 7 where electrochemical reactions occur. The cavity 72 formed by the casing 71 may contain one or more electrode assemblies 73. The electrode assembly 73 may be a wound structure, a stacked structure, or a hybrid structure of wound and stacked.

[0088] The electrode assembly 73 includes a positive electrode 731 and a negative electrode 731 stacked together. In the electrode assembly 73 with a wound structure, the stacked positive electrode 731 and negative electrode 731 are wound together.

[0089] In the electrode assembly 73 with a stacked structure, multiple positive electrode sheets 731 and multiple negative electrode sheets 731 are respectively provided, and the multiple positive electrode sheets 731 and multiple negative electrode sheets 731 are alternately stacked. Exemplarily, multiple positive electrode sheets 731 can be provided, and multiple negative electrode sheets 731 can be folded to form multiple stacked folded segments, with a positive electrode sheet 731 sandwiched between adjacent folded segments. As an example, both the positive electrode sheet 731 and the negative electrode sheet 731 are folded to form multiple stacked folded segments.

[0090] For example, the electrode assembly 73 may be cylindrical, flat, or polygonal in shape.

[0091] The electrode 731 can be either the positive electrode 731 or the negative electrode 731 described in the aforementioned technical solution. The current collector 7311 can be a substrate structure within the electrode 731, used to support and set other structural components such as the active material layer 7312 in the electrode 731, and capable of conducting and collecting the current generated by the active material. The current collector 7311 can be a metal foil, such as copper foil or aluminum foil, or it can be a composite current collector 7311 formed by a polymer base layer and a metal layer.

[0092] The current collector 7311 has two surfaces spaced apart in the thickness direction. These surfaces can be used to deposit the active material layer 7312 so that the active material layer 7312 can be supported on the first current collector 7311.

[0093] The active material layer 7312 can be a layered structure formed by active materials. It can be disposed on one surface of the current collector 7311, or the active material layer 7312 can be disposed on both opposite surfaces of the current collector 7311.

[0094] The connecting layer 7313 can be a coating structure used to connect the solid electrolyte layer 7314 to the active material layer 7312, thereby improving the adhesion strength between the solid electrolyte layer 7314 and the active material layer 7312. The connecting layer 7313 can make the surface of the active material layer 7312 facing away from the current collector 7311 smooth and flat, compensating for any unevenness on the surface of the active material layer 7312 facing away from the current collector 7311. Exemplarily, the connecting layer 7313 may include an adhesive and conductive graphite, such that the connecting layer 7313 can both bond the active material layer 7312 and the solid electrolyte layer 7314 and conduct electricity.

[0095] The solid electrolyte layer 7314 can be a structural layer disposed between the positive electrode 731 and the negative electrode 731, which can simultaneously serve the functions of ion transport and isolation between the positive and negative electrodes. By including the solid electrolyte layer 7314 in the electrode 731, and placing the solid electrolyte layer 7314 on the surface of the active material layer 7312 away from the current collector 7311, the electrode 731 becomes a composite electrode 731 with the solid electrolyte layer 7314. This makes the electrode 731 itself insulating, and also helps to reduce the thickness of the electrode assembly 73, thereby helping to improve the energy density of the battery cell 7.

[0096] The groove region 73131 can refer to at least a portion of the surface of the connecting layer 7313 facing away from the active material layer 7312. This region has an inwardly recessed groove 73132, so that when the solid electrolyte layer 7314 is disposed on the surface of the connecting layer 7313 facing away from the active material layer 7312, the solid electrolyte layer 7314 covering the groove region 73131 can partially enter the groove 73132 and connect to the inner wall of the groove 73132. This increases the thickness of the solid electrolyte corresponding to the groove region 73131. In addition, the partial entry of the solid electrolyte layer 7314 into the groove 73132 and its connection to the inner wall of the groove 73132 can also increase the contact area between the solid electrolyte layer 7314 and the connecting layer 7313, which is beneficial to increasing the connection strength between the solid electrolyte layer 7314 and the connecting layer 7313, making the solid electrolyte layer 7314 less likely to fall off.

[0097] In the above structure, since the surface of the connecting layer 7313 facing away from the active material layer 7312 has a groove region 73131 with a groove 73132, and the solid electrolyte layer 7314 is disposed on the surface of the connecting layer 7313 with the groove region 73131, and part of the solid electrolyte layer 7314 enters the groove 73132 and is connected to the inner wall of the groove 73132, not only does the solid electrolyte layer 7314 in the groove region 73131 have a large thickness, but it also makes the solid electrolyte layer 7314 in the groove region 73131 and the connecting layer 7313 have a large contact area. The solid electrolyte layer 7314 is not easy to fall off, reducing the possibility of failure due to small thickness or falling off. It also makes it less likely for adjacent two electrodes 731 to overlap and short-circuit, which is beneficial to improving the reliability of the battery cell 7.

[0098] In some embodiments, referring to Figures 5 and 6, the current collector 7311 includes a blank area 73111 and a coating area 73112 disposed along a first direction X. The coating area 73112 is provided with an active material layer 7312, while the blank area 73111 is not provided with an active material layer 7312. The connecting layer 7313 includes two end faces disposed opposite to each other along the first direction X. The end faces are connected to the surface of the connecting layer 7313 away from the active material layer 7312. The groove area 73131 includes two sub-areas 73133, which are respectively connected to the two end faces.

[0099] The coated area 73112 and the blank area 73111 can be two interconnected and different parts of the current collector 7311. The coated area 73112 can be the part coated with the active material layer 7312, and the blank area 73111 can be the part not coated with the positive electrode active material layer 7312. By arranging the coated area 73112 and the blank area 73111 along a first direction X, different parts of the current collector 7311 are sequentially arranged in the first direction X. Exemplarily, the blank area 73111 can form a tab extending outward along the first direction X, which is used for electrical connection with an electrode terminal to output the current from the electrode 731.

[0100] The end faces can be two surfaces of the connecting layer 7313 that are arranged opposite each other along the first direction X. The end faces are connected to the surface of the connecting layer 7313 that is away from the active material layer 7312, and the material of the connecting layer 7313 is located between the two end faces in the first direction X.

[0101] Sub-region 73133 can be a portion of the groove region 73131. By making the groove region 73131 include two sub-regions 73133, and the two sub-regions 73133 are respectively connected to two end faces, the two sub-regions 73133 are respectively connected to the two opposite edges of the connecting layer 7313 in the first direction X, and the connecting layer 7313 is provided with grooves 73132 at the two opposite edges in the first direction X.

[0102] Since the solid electrolyte layer 7314 is typically formed by a coating process, it is formed by coating a solid electrolyte slurry onto the surface of the connecting layer 7313 away from the active material layer 7312 and then drying it. A groove 73132 is provided on the sub-region 73133 connected to the edge of the connecting layer 7313 in the first direction X. This allows the solid electrolyte slurry to flow into the groove 73132 when it is coated onto the edge of the connecting layer 7313 in the first direction X, forming an interlocking force with the connecting layer 7313. This reduces the fluidity of the solid electrolyte slurry, making it less likely for it to flow away from the edge of the connecting layer 7313 in the first direction X to the blank area 73111. This helps to reduce the reduction in the thickness of the solid electrolyte layer 7314 caused by the flow of the solid electrolyte slurry.

[0103] In some embodiments, referring to FIG7, two sub-regions 73133 are spaced apart along a first direction X.

[0104] Since the solid electrolyte layer 7314 is typically formed by a coating process, the loss of the solid electrolyte slurry usually occurs at the edge of the bonding layer 7313 in the first direction X.

[0105] By arranging two sub-regions 73133 at intervals along the first direction X, the area between the two sub-regions 73133 is a region without grooves 73131. This means that the surface of the connecting layer 7313 facing away from the active material layer 7312 does not have grooves 73132 in the middle region of the first direction X, which helps to reduce the area of ​​the groove region 73131. Since the groove region 73131 requires the grooves 73132 to be machined, reducing the area of ​​the groove region 73131 helps to reduce the amount of processing work and lower the production cost of the electrode 731.

[0106] In some embodiments, referring to FIG8, two sub-regions 73133 are connected in the first direction X.

[0107] By connecting the two sub-regions 73133 in the first direction X, the groove region 73131 formed by the two sub-regions 73133 can cover the entire surface of the connecting layer 7313 facing away from the active material layer 7312. This results in the groove 73132 being provided on the entire surface of the connecting layer 7313 facing away from the active material layer 7312. This is beneficial to increasing the thickness of the entire active material layer 7312 provided on the surface of the connecting layer 7313 facing away from the active material layer 7312, making it less likely for adjacent electrodes 731 to overlap and short-circuit, and improving the reliability of the battery cell 7.

[0108] In some embodiments, the sub-region 73133 extends through the connecting layer 7313 along the second direction Y, and the second direction Y is perpendicular to the first direction X.

[0109] The second direction Y can be a direction perpendicular to the first direction X along the surface of the connecting layer 7313 away from the active material layer 7312. By setting the sub-region 73133 to penetrate the connecting layer 7313 along the second direction Y, the sub-region 73133 can be formed in the entire edge region of the surface of the connecting layer 7313 away from the active material layer 7312 in the first direction X. This makes it less likely for the solid electrolyte slurry to flow away from the entire edge region of the surface of the connecting layer 7313 away from the active material layer 7312, thus reducing the thickness of the solid electrolyte layer 7314. This helps to reduce the possibility of failure of the solid electrolyte layer 7314 at the edge portion of the surface of the connecting layer 7313 away from the active material layer 7312.

[0110] In some embodiments, the area of ​​the groove region 73131 is set to A, the area of ​​the surface of the connecting layer 7313 facing away from the active material layer 7312 is set to B, and A / B≥10%.

[0111] By setting the area of ​​the groove region 73131 to A, setting the area of ​​the surface of the connecting layer 7313 facing away from the active material layer 7312 to B, and setting the relationship between the area of ​​the groove region 73131 and the area of ​​the surface of the connecting layer 7313 facing away from the active material layer 7312 to A / B≥10%, the groove region 73131 occupies a sufficiently large proportion of the surface of the connecting layer 7313 facing away from the active material layer 7312. The groove region 73131 is sufficient to correspond to the relatively thin solid electrolyte layer 7314 (mainly the edge region of the connecting layer 7313 in the first direction X), so that the solid electrolyte layer 7314 covering the connecting layer 7313 can be acted upon by the groove region 73131 with a sufficiently large area, thereby increasing the thickness of the solid electrolyte layer 7314 in this region. This helps to reduce the possibility of short circuits caused by the overlap of adjacent electrodes 731, and helps to improve the reliability of the battery cell 7.

[0112] For example, A / B ≥ 20%.

[0113] By setting the relationship between the area of ​​the groove region 73131 and the area of ​​the surface of the connecting layer 7313 facing away from the active material layer 7312 to A / B≥20%, the groove region 73131 occupies a sufficiently large proportion of the surface of the connecting layer 7313 facing away from the active material layer 7312. The groove region 73131 is sufficient to correspond to the relatively thin solid electrolyte layer 7314, so that the solid electrolyte layer 7314 covering the connecting layer 7313 can be acted upon by the groove region 73131 with a sufficiently large area. This increases the thickness of the solid electrolyte layer 7314 in this area, which helps to reduce the possibility of short circuit due to overlap between adjacent electrodes 731 and improves the reliability of the battery cell 7.

[0114] In some embodiments, referring to FIG7, a plurality of grooves 73132 are provided, and the plurality of grooves 73132 are spaced apart along the second direction Y to form a groove group 73134. A plurality of groove groups 73134 are provided, and the plurality of groove groups 73134 are spaced apart along the first direction X. The second direction Y is perpendicular to the first direction X.

[0115] By providing multiple grooves 73132 in the groove area 73131, the grooves 73132 can function well to accommodate the solid electrolyte layer 7314.

[0116] The groove assembly 73134 can be a combination of multiple grooves 73132 spaced apart along the second direction Y. These grooves 73132 can be of the same type or different types, and can be configured according to the specific circumstances. By including multiple grooves 73132 spaced apart along the second direction Y in the groove assembly 73134, the groove assembly 73134 can be arranged through the second direction Y on the surface of the connecting layer 7313.

[0117] By setting up multiple groove groups 73134 and spacing them apart along the first direction X, the groove area 73131 formed by the groove 73132 has a sufficient width in the first direction X, which can function on a solid electrolyte layer 7314 of sufficient width.

[0118] In some embodiments, the spacing between two adjacent grooves 73132 in the second direction Y is set to E, where 1μm≤E≤10000μm, and the spacing between two adjacent groove groups 73134 in the first direction X is set to F, where 1μm≤F≤10000μm.

[0119] The spacing between two adjacent grooves 73132 in the second direction Y is set to E. Specifically, the spacing between two adjacent grooves 73132 in the groove group 73134 in the second direction Y is set to E. By setting the range of the spacing E between two adjacent grooves 73132 in the second direction Y to 1μm≤E≤10000μm, not only is there sufficient density of grooves 73132 in the second direction Y to act on the solid electrolyte layer 7314, but the density of grooves 73132 in the second direction Y is also prevented from being too large, thus avoiding high processing costs.

[0120] By setting the interval F between two adjacent tank groups 73134 in the first direction X to a range of 1μm≤F≤10000μm, not only is there sufficient density of tank group 73134 in the first direction X to act on the solid electrolyte layer 7314, but the density of tank group 73134 in the first direction X is also not too large, which would result in high processing costs.

[0121] In some embodiments, the cross-sectional shape of the groove 73132 is configured as at least one of a circle, triangle, rectangle or polygon, and the cross-section is parallel to the surface of the connecting layer 7313 opposite to the active material layer 7312.

[0122] The cross-section of the groove 73132 refers to the cross-section parallel to the surface of the connecting layer 7313 facing away from the active material layer 7312. The cross-sectional shape of the groove 73132 is configured as at least one of the following: circular, triangular, rectangular, or polygonal. It can mean that the cross-sectional shapes of multiple grooves 73132 on the surface of the connecting layer 7313 facing away from the active material layer 7312 are all circular, triangular, rectangular, or polygonal, or it can mean that the cross-sectional shapes of multiple grooves 73132 on the surface of the connecting layer 7313 facing away from the active material layer 7312 include two, three, or four of the following: circular, triangular, rectangular, or polygonal.

[0123] For example, the cross-sectional shape of the groove 73132 can also be configured as other irregular closed curves, and those skilled in the art can set the cross-sectional shape of the groove 73132 according to the actual situation.

[0124] In some embodiments, the cross-sectional shape of the groove 73132 is configured as circular, and the diameter of the groove 73132 is set as G, where 1μm≤G≤10000μm.

[0125] By configuring the cross-sectional shape of the groove 73132 as circular, the groove 73132 can be a cylindrical groove, a conical groove, or a hemispherical groove.

[0126] By setting the diameter G of the groove 73132 to the range of 1μm≤G≤10000μm, not only is the size of a single groove 73132 sufficient to allow solid electrolyte slurry to enter, but the size of a single groove 73132 is also not too large to affect the structural strength of the connecting layer 7313.

[0127] In some embodiments, referring to FIG8, the groove 73132 penetrates the connecting layer 7313 along the second direction Y, and multiple grooves 73132 are provided, with the multiple grooves 73132 spaced apart along the first direction X.

[0128] By making the groove 73132 penetrate the connecting layer 7313 along the second direction Y, the groove 73132 becomes a through groove extending along the second direction Y. This allows the solid electrolyte slurry to flow along the second direction Y after entering the groove 73132, rather than flowing along the first direction X to the blank area 73111. This helps to reduce the reduction in the thickness of the solid electrolyte layer 7314 caused by the solid electrolyte slurry flowing to the blank area 73111.

[0129] By arranging multiple grooves 73132 at intervals along the first direction X, the multiple grooves 73132 can effectively reduce the possibility of solid electrolyte slurry flowing into the blank area 73111.

[0130] For example, a plurality of grooves 73132 are equally spaced along the first direction X, such that the ability of the grooves 73132 to block the flow of solid electrolyte slurry in the first direction X is uniformly distributed.

[0131] In some embodiments, the spacing between two adjacent grooves 73132 in the first direction X is set to D, where 1μm≤D≤10000μm.

[0132] By setting the range of the interval D between two adjacent grooves 73132 in the first direction X to 1μm≤D≤10000μm, not only is the ability of the solid electrolyte slurry to flow to the blank area 73111 not reduced due to the excessively large interval of the grooves 73132 in the first direction X, but the structural strength of the connecting layer 7313 is also not reduced due to the excessively small interval of the grooves 73132 in the first direction X.

[0133] In some embodiments, the groove 73132 is formed by laser etching or chemical etching.

[0134] The groove 73132 is formed by laser etching, which means that the groove 73132 is formed by processing the surface of the connecting layer 7313 away from the active material layer 7312 using a laser. The groove 73132 is formed by chemical etching, which means that the groove 73132 is formed by etching the surface of the connecting layer 7313 away from the active material layer 7312 with chemical reagents.

[0135] In some embodiments, the size of the groove 73132 is set to C along the thickness direction of the connecting layer 7313, where 1μm≤C≤2000μm.

[0136] By setting the dimension C of the groove 73132 along the thickness direction of the connecting layer 7313 to a range of 1μm≤C≤2000μm, not only is the groove 73132 sufficiently deep to accommodate the solid electrolyte layer 7314, but the groove 73132 is also prevented from damaging the structural strength of the connecting layer 7313 due to excessive depth.

[0137] In some embodiments, 5μm≤C≤500μm.

[0138] By setting the dimension C of the groove 73132 along the thickness direction of the connecting layer 7313 to a range of 5μm≤C≤500μm, for example, the dimension C of the groove 73132 along the thickness direction of the connecting layer 7313 can be 5μm, 100μm, 200μm, 300μm, 400μm or 500μm. Those skilled in the art can set the dimension of the groove 73132 along the thickness direction of the connecting layer 7313 according to the actual situation such as the thickness of the connecting layer 7313, so that the groove 73132 has sufficient depth to accommodate the solid electrolyte layer 7314 without damaging the structural strength of the connecting layer 7313 due to excessive depth.

[0139] In some embodiments, the interlayer peel strength between the solid electrolyte layer 7314 and the connecting layer 7313 is set to H, where 5 N / m ≤ H ≤ 10 N / m.

[0140] For example, the interlayer peel strength between the solid electrolyte layer 7314 and the connecting layer 7313 can be obtained by measuring according to the national standard GB / T 2792-2014. The specific measurement method can be referred to the national standard GB / T 2792-2014, and will not be elaborated here.

[0141] By setting the interlayer peel strength H between the solid electrolyte layer 7314 and the connecting layer 7313 to a range of 5 N / m ≤ H ≤ 10 N / m, the connection between the solid electrolyte layer 7314 and the connecting layer 7313 is not only strong, but the solid electrolyte layer 7314 is also less likely to fall off the connecting layer 7313, making it less likely for adjacent electrodes 731 to overlap and short-circuit, which is beneficial to improving the reliability of the battery cell 7. Furthermore, the connection strength between the solid electrolyte layer 7314 and the connecting layer 7313 is not too high, which would make the processing of the electrode 731 more difficult or costly.

[0142] For example, the interlayer peel strength H between the solid electrolyte layer 7314 and the connecting layer 7313 can be set to a range of 7N / m≤H≤10N / m. For example, the interlayer peel strength H between the solid electrolyte layer 7314 and the connecting layer 7313 can be 7N / m, 8N / m, 9N / m or 10N / m, so that the connection between the solid electrolyte layer 7314 and the connecting layer 7313 is firm, the solid electrolyte layer 7314 is not easy to fall off from the connecting layer 7313, and the processing cost of the electrode 731 is not too high.

[0143] Some embodiments of this application provide a method for manufacturing a battery cell 7. Referring to FIG9, the method for manufacturing the battery cell 7 includes the following steps:

[0144] S1. Provides a housing 71 and a current collector 7311 with an active material layer 7312 on its surface.

[0145] As described in the aforementioned technical solution, the outer casing 71 in step S1 is a component that houses other parts such as the electrode assembly 73 in the battery cell 7. The active material layer 7312 can be formed by coating the surface of the current collector 7311 with an active material slurry through a coating process, and the active material slurry is dried after drying.

[0146] S2. Coat the surface of the active material layer 7312 away from the current collector 7311 with a bonding slurry and dry it to form the bonding layer 7313.

[0147] In step S2, a bonding slurry is coated onto the surface of the active material layer 7312 facing away from the current collector 7311 using a coating process, so that the bonding slurry covers the active material layer 7312. After the bonding slurry dries, it will solidify on the surface of the active material layer 7312 facing away from the current collector 7311 to form a bonding layer 7313.

[0148] S3. Grooves 73132 are machined in the groove area 73131 on the surface of the connecting layer 7313 away from the active material layer 7312.

[0149] In step S3, the groove region 73131 can be a region defined on the surface of the connecting layer 7313 facing away from the active material layer 7312, and the groove region 73131 can be a region of the corresponding solid electrolyte layer 7314 that is prone to failure. For example, the groove region 73131 can be a region near the two opposite edges of the connecting layer 7313 in the first direction X.

[0150] Grooves 73132 are formed on the groove area 73131 of the connecting layer 7313 away from the active material layer 7312 by removing material, so that the grooves 73132 can accommodate and block the flow of the solid electrolyte slurry.

[0151] S4. Coat the surface of the connecting layer 7313 away from the active material layer 7312 with a solid electrolyte slurry and dry it to obtain an electrode 731 with a solid electrolyte layer 7314.

[0152] In step S4, a solid electrolyte slurry is coated onto the surface of the connecting layer 7313 facing away from the active material layer 7312, so that the solid electrolyte slurry covers the connecting layer 7313, wherein the groove region 73131 is covered by the solid electrolyte slurry. After the solid electrolyte slurry is dried, it will solidify on the surface of the connecting layer 7313 facing away from the active material layer 7312 to form a solid electrolyte layer 7314, so that the electrode 731 has a solid electrolyte layer 7314.

[0153] S5. The electrode sheets 731 are stacked to form an electrode assembly 73.

[0154] In step S5, stacking the electrode sheets 731 to form the electrode assembly 73 can mean that the stacked positive electrode sheets 731 and negative electrode sheets 731 are wound to form an electrode assembly 73 with a wound structure; or it can mean that multiple positive electrode sheets 731 and multiple negative electrode sheets 731 are alternately stacked to form an electrode assembly 73 with a stacked structure.

[0155] S6. The electrode assembly 73 is installed into the housing 71 to form a battery cell 7.

[0156] In step S6, a battery cell 7 is formed by installing the electrode assembly 73 into the housing 71 and connecting the tabs of the electrode assembly 73 to the electrode terminals of the housing 71.

[0157] In some embodiments, the current collector 7311 includes a blank area 73111 and a coating area 73112 disposed along a first direction X. The coating area 73112 is provided with an active material layer 7312, while the blank area 73111 is not provided with an active material layer 7312. The connecting layer 7313 includes two end faces disposed opposite to each other along the first direction X. The end faces are connected to the surface of the connecting layer 7313 away from the active material layer 7312. The groove area 73131 includes two sub-areas 73133, which are respectively connected to the two end faces. The step of forming a groove 73132 in the groove area 73131 on the surface of the connecting layer 7313 away from the active material layer 7312 includes: processing the groove 73132 in the sub-area 73133.

[0158] As described in the foregoing technical solution, the groove region 73131 includes two sub-regions 73133 that are respectively connected to the two end faces, such that the two sub-regions 73133 are regions connected to the two opposite edges of the connecting layer 7313 in the first direction X.

[0159] By processing grooves 73132 in sub-region 73133, the grooves 73132 are located in the region connecting the two opposite edges of the connecting layer 7313 in the first direction X. When the solid electrolyte slurry is applied to the edge of the connecting layer 7313 in the first direction X, the solid electrolyte slurry will flow into the grooves 73132 and form an interlocking force with the connecting layer 7313. This reduces the fluidity of the solid electrolyte slurry, making it less likely for the solid electrolyte slurry to flow away from the edge of the connecting layer 7313 in the first direction X to the blank area 73111. This helps to reduce the reduction in the thickness of the solid electrolyte layer 7314 caused by the flow of solid electrolyte slurry.

[0160] In some embodiments, the groove 73132 is formed by laser grooving or chemical etching.

[0161] The groove 73132 can be formed by laser grooving, which can be achieved by using a laser to process the surface of the connecting layer 7313 away from the active material layer 7312. Alternatively, the groove 73132 can be formed by chemical etching, which can be achieved by using chemical reagents to etch the surface of the connecting layer 7313 away from the active material layer 7312.

[0162] Some embodiments of this application also provide a battery device 2, which includes the battery cell 7 provided by the above-described technical solution.

[0163] Some embodiments of this application also provide an electrical device, which includes the battery device 2 provided by the above-described technical solution, the battery device 2 being used to provide electrical energy.

[0164] Some embodiments of this application provide a battery cell 7, which includes a housing 71 and an electrode assembly 73. The electrode assembly 73 is disposed in the cavity 72 of the housing 71. The electrode assembly 73 includes stacked electrode sheets 731. The electrode sheet 731 includes a current collector 7311, an active material layer 7312, a connecting layer 7313 and a solid electrolyte layer 7314 stacked sequentially. The active material layer 7312 is disposed on the surface of the current collector 7311. The connecting layer 7313 is disposed on the surface of the active material layer 7312 away from the current collector 7311. The surface of the connecting layer 7313 away from the active material layer 7312 has a groove region 73131 with an inwardly recessed groove 73132. The current collector 7311 includes a blank area 73111 and a coating area 73112 disposed along the first direction X. The coating area 73112 is provided with an active material layer 7312, while the blank area 73111 is not provided with an active material layer 7312. The connecting layer 7313 includes two end faces disposed opposite to each other along the first direction X. The end faces are connected to the surface of the connecting layer 7313 away from the active material layer 7312. The groove area 73131 includes two sub-areas 73133 respectively connected to the two end faces. The two sub-areas 73133 are disposed at intervals along the first direction X.

[0165] In the above structure, since the surface of the connecting layer 7313 facing away from the active material layer 7312 has a groove region 73131 with a groove 73132, and the solid electrolyte layer 7314 is disposed on the surface of the connecting layer 7313 with the groove region 73131, and part of the solid electrolyte layer 7314 enters the groove 73132 and is connected to the inner wall of the groove 73132, not only does the solid electrolyte layer 7314 in the groove region 73131 have a large thickness, but it also makes the solid electrolyte layer 7314 in the groove region 73131 and the connecting layer 7313 have a large contact area. The solid electrolyte layer 7314 is not easy to fall off, reducing the possibility of failure due to small thickness or falling off. It also makes it less likely for adjacent two electrodes 731 to overlap and short-circuit, which is beneficial to improving the reliability of the battery cell 7.

[0166] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and not to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application, and they should all be covered within the scope of the claims and specification of this application. In particular, as long as there is no structural conflict, the various technical features mentioned in the embodiments can be combined in any way. This application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A single battery cell, comprising: The outer shell forms a cavity; An electrode assembly is disposed in the cavity. The electrode assembly includes stacked electrode sheets, each electrode sheet including a current collector, an active material layer, a connecting layer, and a solid electrolyte layer. The active material layer is disposed on the surface of the current collector. The connecting layer is disposed on the surface of the active material layer opposite to the current collector. The surface of the connecting layer opposite to the active material layer has a groove area with an inwardly recessed groove. The solid electrolyte layer is disposed on the surface of the connecting layer opposite to the active material layer and covers the groove area. A portion of the solid electrolyte layer enters the groove and is connected to the inner wall of the groove. The current collector includes a blank area and a coated area arranged along a first direction. The coated area is provided with the active material layer, while the blank area is not provided with the active material layer. The connecting layer includes two end faces arranged opposite to each other along the first direction. The end faces are connected to the surface of the connecting layer away from the active material layer. The groove area includes two sub-areas, which are respectively connected to the two end faces. The two sub-areas are spaced apart along the first direction.

2. The battery cell according to claim 1, wherein, Along the second direction, the sub-region extends through the connecting layer, and the second direction is perpendicular to the first direction.

3. The battery cell according to claim 1 or 2, wherein, The area of ​​the groove region is set as A, and the area of ​​the surface of the connecting layer facing away from the active material layer is set as B, where A / B ≥ 10%.

4. The battery cell according to any one of claims 1-3, wherein, The groove is provided in multiple ways, and the multiple grooves are spaced apart along the second direction to form a groove group. The groove group is provided in multiple ways, and the multiple groove groups are spaced apart along the first direction. The second direction is perpendicular to the first direction.

5. The battery cell according to claim 4, wherein, The spacing between two adjacent grooves in the second direction is set to E, where 1μm≤E≤10000μm, and the spacing between two adjacent groove groups in the first direction is set to F, where 1μm≤F≤10000μm.

6. The battery cell according to claim 4 or 5, wherein, The cross-sectional shape of the groove is configured as at least one of a circle, triangle, rectangle or polygon, and the cross-section is parallel to the surface of the connecting layer opposite to the active material layer.

7. The battery cell according to claim 6, wherein, The groove has a circular cross-sectional shape and a diameter G, where 1μm≤G≤10000μm.

8. The battery cell according to claim 2, wherein, The groove extends through the connecting layer along the second direction, and there are multiple grooves, which are spaced apart along the first direction.

9. The battery cell according to claim 8, wherein, The spacing between two adjacent grooves in the first direction is set to D, where 1μm≤D≤10000μm.

10. The battery cell according to any one of claims 1-9, wherein, The grooves are formed by laser etching or chemical etching.

11. The battery cell according to any one of claims 1-10, wherein, Along the thickness direction of the connecting layer, the size of the groove is set to C, where 1μm≤C≤2000μm.

12. The battery cell according to claim 11, wherein, 5μm≤C≤500μm.

13. The battery cell according to any one of claims 1-12, wherein, The interlayer peel strength between the solid electrolyte layer and the connecting layer is set to H, where 5 N / m ≤ H ≤ 10 N / m.

14. A method for manufacturing a single battery cell, comprising: Provides a housing and a current collector with an active material layer on its surface; A bonding slurry is coated onto the surface of the active material layer opposite to the current collector and then dried to form a bonding layer; The groove is formed in the groove region on the surface of the connecting layer opposite to the active material layer; A solid electrolyte slurry is coated on the surface of the connecting layer opposite to the active material layer and then dried to obtain an electrode with a solid electrolyte layer. The electrode sheets are stacked and arranged to form an electrode assembly; The electrode assembly is installed into the housing to form a battery cell.

15. The method for manufacturing a battery cell according to claim 14, wherein, The current collector includes a blank area and a coated area arranged along a first direction. The coated area is provided with the active material layer, while the blank area is not provided with the active material layer. The connecting layer includes two end faces arranged opposite to each other along the first direction. The end faces are connected to the surface of the connecting layer away from the active material layer. The groove area includes two sub-areas, each of which is connected to one of the two end faces. The step of forming a groove in the groove area on the surface of the connecting layer away from the active material layer includes: The groove is machined in the sub-region.

16. The method for manufacturing a battery cell according to claim 14 or 15, wherein, The grooves are created by laser etching or chemical etching.

17. A battery device comprising a battery cell as described in any one of claims 1-13.

18. An electrical device comprising the battery device as claimed in claim 17, the battery device being used to provide electrical energy.

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