Battery cell, manufacturing method thereof and electric equipment

Abstract

The embodiment of the invention provides a battery cell, a manufacturing method thereof and electric equipment. The battery cell comprises a shell, an electrode assembly and filler. The electrode assembly comprises a first electrode assembly and a second electrode assembly, the first electrode assembly and the second electrode assembly are stacked in the first direction, in the second direction, the length of the second electrode assembly is larger than that of the first electrode assembly, the second electrode assembly is provided with a first surface facing the first electrode assembly, and when observed in the first direction, the length of the first surface is larger than that of the second surface. The second electrode assembly is provided with an overlapping area overlapped with the first electrode assembly and a non-overlapping area not overlapped with the first electrode assembly, and the side wall, close to the non-overlapping area, of the first electrode assembly in the second direction and the first surface of the non-overlapping area form a first step; the shell forms a second step corresponding to the first step, and an accommodating space is formed between the first step and the second step; the second direction is perpendicular to the first direction; the filler is arranged in the containing space. According to the technical scheme, the safety and reliability of the battery cell can be improved.

Description

[0001] This application is a divisional application based on the invention with application number 202510167583.5, application date February 14, 2025, applicant Ningde New Energy Technology Co., Ltd., and invention title "Battery cell and manufacturing method thereof, electrical equipment". Technical Field

[0002] This application relates to the field of battery cell technology, and more specifically, to a battery cell, its manufacturing method, and an electrical device thereof. Background Technology

[0003] In recent years, with the rapid development of new energy technologies, batteries have been widely used in electronic devices, electric vehicles, electric two-wheelers, power tools and other electrical equipment.

[0004] As the application scenarios for battery cells increase, their shapes also change to meet different installation environments. Within a single battery cell, multiple electrode assemblies of different sizes are incorporated, creating a step between adjacent assemblies. However, at the junctions of these electrode assemblies of different sizes, external pressure is applied, leading to poor electrode interfaces in this area. This can result in black spots and metal ion deposition risks during cycling, reducing the cell's safety and reliability. Summary of the Invention

[0005] This application provides a battery cell, a method for manufacturing the same, and an electrical device thereof, which can improve the safety and reliability of the battery cell.

[0006] This application is achieved through the following technical solution: In a first aspect, embodiments of this application provide a battery cell, which includes a housing, an electrode assembly, and a filler. The electrode assembly is housed within the housing and includes a first electrode assembly and a second electrode assembly. The first and second electrode assemblies are stacked along a first direction. Along a second direction, the length of the second electrode assembly is greater than the length of the first electrode assembly. The second electrode assembly has a first surface facing the first electrode assembly. Viewed along the first direction, the second electrode assembly has an overlapping region that overlaps with the first electrode assembly and a non-overlapping region that does not overlap with the first electrode assembly. A first step is formed on the sidewall of the first electrode assembly near the non-overlapping region and the first surface of the non-overlapping region in the second direction. The housing forms a second step corresponding to the first step, and a receiving space is formed between the first step and the second step. The second direction is perpendicular to the first direction. The filler is disposed in the receiving space.

[0007] According to the battery cell of this application embodiment, a first electrode assembly and a second electrode assembly form a first step, and a housing forms a second step corresponding to the first step, so as to facilitate the assembly of the electrode assembly and the housing, making the battery cell a stepped structure to adapt to different application scenarios. During the assembly of the electrode assembly and the housing, a receiving space is formed between the first step of the electrode assembly and the second step of the housing. This receiving space can contain electrolyte, which is beneficial for the charge-discharge cycle of the battery cell. By placing a filler in the receiving space, either filling the receiving space completely or combining the filler with the electrolyte in the receiving space, the pressure during the battery cell manufacturing process can be effectively transmitted to the area corresponding to the second electrode assembly and the receiving space. This helps to increase the stress consistency of this area and other areas of the second electrode assembly, resulting in higher adhesion between the negative electrode sheet and the corresponding separator, reducing the risk of metal ion deposition on the surface of the negative electrode sheet, and giving the battery cell higher safety and reliability.

[0008] In one or more of the above alternative embodiments, the filler includes organic materials.

[0009] Organic materials have high toughness and can provide physical support, which is conducive to the effective and uniform transmission of pressure.

[0010] In one or more of the above optional embodiments, the filler includes a mixture of organic and inorganic materials, wherein the inorganic materials account for 1% to 95% of the mass of the mixture.

[0011] Inorganic materials can improve the hardness of the filler. Simultaneously, inorganic materials possess a certain ability to absorb or transport electrolyte, effectively improving the electrolyte wettability of the electrode assembly and the corresponding area of ​​the containment space. A mixture of organic and inorganic materials results in a filler that not only possesses high mechanical strength and toughness but also absorbs or transports electrolyte. This facilitates the effective transfer of pressure during the cell manufacturing process to the area corresponding to the second electrode assembly and the containment space, ensuring consistent stress distribution between this area and other areas of the second electrode assembly. This further improves the electrolyte wettability of the portion of the electrode assembly corresponding to the containment space, and further effectively improves the interface at the junction of the second and first electrode assemblies.

[0012] If the inorganic material accounts for too small a mass proportion in the mixture, the mixture will have a poor effect on absorbing or transporting electrolyte, and the electrolyte wettability of the electrode assembly and the corresponding area of ​​the containment space will be poor. If the inorganic material accounts for too large a mass proportion in the mixture, the organic material in the mixture will have a small mass proportion, the mixture will be weak, and it will not be conducive to uniform pressure transmission.

[0013] By setting the mass percentage of inorganic materials in the mixture to be greater than or equal to 1% and less than or equal to 95%, on the one hand, the effect of the mixture in absorbing and transporting electrolyte can be improved, and the electrolyte wettability of the electrode assembly and the corresponding area of ​​the containment space can be improved; on the other hand, the mixture has high toughness, which is conducive to uniform pressure transmission.

[0014] In one or more of the above optional embodiments, the inorganic material accounts for 5% to 90% of the mass of the mixture.

[0015] When the inorganic material accounts for 5% or more of the mass of the mixture, it further improves the absorption and transport of electrolyte, and enhances the electrolyte wettability of the electrode assembly and the corresponding area of ​​the containment space. When the inorganic material accounts for 90% or less of the mass of the mixture, it further gives the mixture higher toughness, which is beneficial for uniform pressure transmission.

[0016] In one or more of the above optional embodiments, the inorganic material includes at least one of alumina, boehmite, magnesium oxide, magnesium hydroxide, calcium oxide, calcium hydroxide, zinc oxide, barium sulfate, silicon carbide, titanium dioxide, barium titanate, calcium carbonate, silicon oxide, calcium titanate, lithium phosphate, lithium titanium phosphate, lithium aluminum titanium phosphate, lithium nitride, or lithium lanthanum titanate.

[0017] Inorganic materials are selected from at least one of the above materials and have high strength and hardness, good high temperature resistance and high chemical stability. When combined with organic materials, the composite of organic and inorganic materials has high strength and toughness, good high temperature resistance and high chemical stability.

[0018] In one or more of the above optional embodiments, the organic material includes at least one of organosilicon, polyurethane, epoxy resin, polyethylene, polypropylene, ethylene-acrylic acid copolymer, ethylene-vinyl acetate copolymer, polyester, or polyamide.

[0019] The organic material is selected from at least one of the above materials and has good flexibility and ductility.

[0020] In one or more of the above optional embodiments, the housing includes a first wall and a second wall disposed opposite to each other along a first direction. The first wall has a main wall and a stepped wall. Along the second direction, the stepped wall is located at at least one end of the main wall. The stepped wall is recessed relative to the main wall toward the second wall. The stepped wall and the main wall are connected by a connecting wall to form a second step. A second electrode assembly is disposed between the stepped wall and the second wall. A first electrode assembly is disposed between the main wall and the second electrode assembly. The first electrode assembly, the second electrode assembly, the connecting wall, and the main wall enclose an accommodating space.

[0021] The first wall can be stamped or injection molded to form the second step, which facilitates manufacturing and gives the first wall high overall strength. The second electrode assembly is located between the stepped wall and the second wall, while the first electrode assembly is located between the main body wall and the second electrode assembly. This allows the outer casing to match the contours of the electrode assembly, facilitating the protection of the electrode assembly by the outer casing and reducing the risk of damage to the electrode assembly.

[0022] In one or more of the above optional embodiments, along the first direction, the second electrode assembly has a first region that overlaps with the projection of the accommodating space, the projected area of ​​the first region is S1, and the projected area of ​​the second electrode assembly is S2, satisfying that 0.001≤S1 / S2≤0.2.

[0023] If the ratio of the projected area of ​​the first region to the projected area of ​​the second electrode assembly is too small, the volume of the containment space will be too small, which is not conducive to the assembly of the electrode assembly and the shell, and the pressure transmission effect between the filler and the first region will be poor. If the ratio of the projected area of ​​the first region to the projected area of ​​the second electrode assembly is too large, the volume of the containment space will be too large, the utilization rate of the internal space of the shell will be low, and the energy density of the cell will be low.

[0024] The first region corresponds to the boundary area between the second electrode assembly and the first electrode assembly. When viewed along the first direction, the filler and the first region at least partially overlap. By setting the ratio of the projected area of ​​the first region to the projected area of ​​the second electrode assembly to be greater than or equal to 0.001 and less than or equal to 0.2, on the one hand, it facilitates the assembly of the electrode assembly and the shell, facilitates the transmission of pressure between the filler and the first region, and facilitates a larger adhesion between the negative electrode sheet and the separator in the first region, reducing the risk of metal ions being deposited on the surface of the negative electrode sheet in the first region; on the other hand, the internal space utilization of the shell is high, and the cell has a high energy density.

[0025] In one or more of the above optional embodiments, along the first direction, the projected area of ​​the first electrode assembly is S3 and the projected area of ​​the second electrode assembly is S2, satisfying that 0.2≤S3 / S2≤0.9.

[0026] If the ratio of the projected area of ​​the first electrode assembly to the projected area of ​​the second electrode assembly is too large, the size difference between the first and second electrode assemblies will be too small, making manufacturing more difficult. If the ratio of the projected area of ​​the first electrode assembly to the projected area of ​​the second electrode assembly is too small, the size difference between the first and second electrode assemblies will be too large, which is not conducive to achieving the design goal of increasing the energy density of the battery cell by flexibly utilizing space. Furthermore, if the size difference between the first and second electrode assemblies is too large, the area of ​​the interface region between the first and second electrode assemblies, i.e., the first region, will be larger, making the problem of uneven stress more serious.

[0027] By setting the ratio of the projected area of ​​the first electrode assembly to the projected area of ​​the second electrode assembly to be greater than or equal to 0.2 and less than or equal to 0.9, on the one hand, the processing and manufacturing difficulty is lower; on the other hand, the battery cell has a higher energy density, reducing the uneven stress distribution at the interface between the first electrode assembly and the second electrode assembly.

[0028] In one or more of the above optional embodiments, the filler is connected to the second electrode assembly and / or the housing.

[0029] The filler is connected to the second electrode assembly and / or the housing, which facilitates pressure transmission and ensures the consistency of stress on the corresponding area of ​​the electrode assembly and the housing space, as well as other areas of the second electrode assembly.

[0030] In one or more of the above optional embodiments, along the first direction, the minimum distance between the filler and the outer shell is H, which satisfies that 0≤H≤5mm.

[0031] The outer shell has a certain degree of elasticity. By setting the distance between the filler and the outer shell along the first direction to be greater than or equal to 0 and less than or equal to 5 mm, it is beneficial for the pressure on the outer shell to be transmitted to the first area along the first direction.

[0032] In one or more of the above optional embodiments, 0.4mm ≤ H ≤ 3.5mm.

[0033] When H≥0.4mm, it facilitates the assembly of the electrode assembly and the housing, and can accommodate processing errors; when H≤3.5mm, the distance between the housing and the filler is smaller, which further facilitates the transmission of pressure on the housing to the first region.

[0034] Secondly, embodiments of this application also provide an electrical device that includes a battery cell provided according to any of the above embodiments.

[0035] Thirdly, embodiments of this application also provide a method for manufacturing a battery cell, used to manufacture a battery cell according to any of the above embodiments, the method for manufacturing a battery cell comprising: Provide electrode assemblies; Provide a casing; The slurry is applied to the second step of the outer shell, or to the first step of the electrode assembly, and the electrode assembly is housed within the outer shell, such that the slurry is located in the containment space between the first and second steps, and the slurry solidifies to form a filler.

[0036] The battery cells manufactured using the above-mentioned methods have high safety and reliability.

[0037] In one or more of the above optional embodiments, the initial construction viscosity of the slurry is greater than or equal to 30,000 Pa·s.

[0038] By setting the initial construction viscosity of the slurry to be greater than or equal to 30,000 Pa·s, the slurry has poor fluidity, which reduces the risk of the slurry flowing into the electrode assembly during the cell preparation process and affecting the cell capacity.

[0039] In one or more of the above optional embodiments, the slurry is applied to the second step of the housing or to the first step of the electrode assembly, and the electrode assembly is housed in the housing such that the slurry is located in the housing space between the first step and the second step. The slurry solidifies to form a filler, including: heating and melting the slurry, applying the melted slurry to the second step or the first step, housing the electrode assembly in the housing, and the slurry solidifying to form a filler after cooling.

[0040] The slurry is melted by heat, which melts the organic materials in the slurry, making it easier for the slurry to connect with the shell or electrode components. After the temperature drops to room temperature, the organic materials harden again. Through the material hardening process, the filler is placed in the containment space, and the filler has high hardness, which is conducive to pressure transmission.

[0041] In one or more of the above optional embodiments, the heating temperature of the slurry is 50°C to 300°C.

[0042] If the slurry is heated to too low a temperature, it will not melt sufficiently, which is not conducive to the assembly of the slurry with the shell or electrode assembly; if the slurry is heated to too high a temperature, it will waste energy, and the slurry has high fluidity and will easily flow into the electrode assembly.

[0043] By setting the heating temperature of the slurry to be greater than or equal to 50°C and less than or equal to 300°C, on the one hand, it can be adapted to melting a variety of materials, and the slurry can be melted and coated onto the shell or electrode assembly, which is beneficial to the preparation of the battery cell; on the other hand, it can save energy, and the poor fluidity of the slurry reduces the risk of it flowing into the electrode assembly.

[0044] In one or more of the above optional embodiments, the slurry is applied to the second step of the housing or to the first step of the electrode assembly, and the electrode assembly is housed within the housing such that the slurry is located in the housing space between the first step and the second step. The slurry solidifies to form a filler, including: applying the slurry to the second step or applying the slurry to the first step, housing the electrode assembly within the housing, and causing the slurry to undergo a chemical reaction and solidify to form a filler by heating the battery cell or by catalysis by a catalyst within the slurry.

[0045] Organic materials in the slurry undergo chemical reactions under high temperature or the action of a catalyst, producing cross-linked structures that cause the slurry to harden, giving the filler a high hardness.

[0046] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0047] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0048] Figure 1 Perspective views of the battery cell provided for some embodiments of this application; Figure 2 A perspective view of an electrode assembly provided in some embodiments of this application; Figure 3 This is a schematic diagram of the structure of an electrode assembly provided in some embodiments of this application; Figure 4 This is a partial structural diagram of a battery cell provided in some embodiments of this application.

[0049] Icons: 1000 - Cell; 1 - Casing; 11 - Second Step; 12 - First Wall; 121 - Main Wall; 122 - Step Wall; 123 - Connecting Wall; 13 - Second Wall; 14 - Third Wall; 15 - Fourth Wall; 16 - Fifth Wall; 2 - Electrode Assembly; 2a - First Electrode Assembly; 2b - Second Electrode Assembly; 21 - First Surface; 22 - First Step; 23 - First Region; 24 - Second Region; 25 - Third Region; 3 - Filler; 4 - Accommodation Space; X - Third Direction; Y - Second Direction; Z - First Direction. Detailed Implementation

[0050] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some embodiments of this application, but not all embodiments.

[0051] 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.

[0052] In this application, the reference to "embodiment" means that a specific feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a mutually exclusive, independent, or alternative embodiment. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described in this application can be combined with other embodiments.

[0053] 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.

[0054] 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.

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

[0056] Currently, judging from market trends, the application of battery cells is becoming increasingly widespread. Battery cells are widely used in electric vehicles such as electric bicycles, electric motorcycles, and electric cars, as well as in power tools, mobile phones, tablets, drones, energy storage devices, and many other fields. With the increasing number of application scenarios for battery cells, their shapes are also changing to meet different installation environments. For example, a stepped battery cell may be used, where multiple electrode components of different sizes are set within the same cell, creating a step between adjacent electrode components. For instance, the first step is formed at the junction of the large and small electrode components. Due to the high rigidity of the outer shell, a second step is formed on the outer shell corresponding to the first step to ensure proper assembly of the electrode components, thus matching the contours of the outer shell and the electrode components. However, during the manufacturing process of the battery cell, pressure is applied to the cell. Due to the space between the first and second steps, when the cell is subjected to the pressure of the pressure block, the pressure cannot be directly applied to the area of ​​the second electrode assembly located on the side of the first electrode assembly and corresponding to the space. This results in uneven stress in this area. In other words, external pressure can easily cause uneven stress at the junction of electrode assemblies of different sizes, which weakens the adhesion between the negative electrode sheet and the separator in this area. During charge and discharge cycles, black spots and metal ion precipitation may appear on the surface of the negative electrode sheet in this area, resulting in lower safety and reliability of the battery cell.

[0057] Based on the above considerations, in order to solve the problem of low safety and reliability of the battery cell caused by black spots and metal ion deposition at the junction of electrode components of different sizes, this application provides a battery cell including a shell, electrode components, and filler. The electrode components are housed in the shell and include a first electrode component and a second electrode component. The first electrode component and the second electrode component are stacked along a first direction. Along a second direction, the length of the second electrode component is greater than the length of the first electrode component. The second electrode component has a first surface facing the first electrode component. The sidewall and the first surface of the first electrode component in the second direction form a first step. The shell forms a second step corresponding to the first step, and a receiving space is formed between the first step and the second step. The second direction is perpendicular to the first direction. The filler is disposed in the receiving space.

[0058] In such a cell, by placing the filler in the containment space, either filling the containment space completely or combining the filler with the electrolyte in the containment space, the pressure during the cell manufacturing process can be effectively transmitted to the area corresponding to the containment space of the second electrode assembly. This helps to increase the stress consistency of this area and other areas of the second electrode assembly, resulting in higher adhesion between the negative electrode sheet and the corresponding separator, reducing the risk of lithium metal deposition on the surface of the negative electrode sheet, and giving the cell higher safety and reliability.

[0059] The battery cells disclosed in the embodiments of this application can be used, but are not limited to, in electrical equipment such as electric two-wheelers, electronic devices, power tools, drones, and energy storage devices. They can also be used as the power supply system for electrical equipment, which helps improve the safety performance of the battery cells.

[0060] This application provides an electrical device that uses battery cells as a power source. The electrical device can be, but is not limited to, electronic devices, power tools, electric vehicles, drones, and energy storage devices. Electronic devices can include mobile phones, tablets, laptops, etc.; power tools can include electric drills, chainsaws, etc.; and electric vehicles can include electric cars, electric motorcycles, electric bicycles, etc.

[0061] The structure of the battery cell provided in the embodiments of this application will now be described with reference to the accompanying drawings.

[0062] Please refer to Figures 1 to 4 This application provides a battery cell 1000, which includes a housing 1 and an electrode assembly 2.

[0063] The outer casing 1 has a space for accommodating the electrode assembly 2, and the electrode assembly 2 and the electrolyte are contained within this space. The outer casing 1 can be a rigid shell, for example, it can be a steel shell, an aluminum shell, a rigid plastic shell, etc., and the battery cell 1000 is a rigid shell battery cell.

[0064] Electrode assembly 2 includes a positive electrode, a negative electrode, and a separator. The separator is disposed between the positive and negative electrode to insulate and separate them, reducing the risk of short circuit in cell 1000. The separator can be made of materials such as polypropylene or polyethylene.

[0065] Electrode assembly 2 has a stacked structure, with the positive electrode, separator and negative electrode stacked in a certain order.

[0066] Please refer to Figure 2 and Figure 3 The electrode assembly 2 includes a first electrode assembly 2a and a second electrode assembly 2b, which are stacked along a first direction Z, which may be parallel to the thickness direction of the battery cell 1000. The first electrode assembly 2a includes a first positive electrode, a first negative electrode, and a first separator, which are stacked along the first direction Z. The second electrode assembly 2b includes a second positive electrode, a second negative electrode, and a second separator, which are stacked along the first direction Z.

[0067] Along the second direction Y, the length of the second electrode assembly 2b is greater than the length of the first electrode assembly 2a, and at least one end of the second electrode assembly 2b extends beyond the first electrode assembly 2a. The second direction Y is perpendicular to the first direction Z, and the second direction Y can be parallel to the length direction of the battery cell 1000, or the second direction Y can be parallel to the width direction of the battery cell 1000.

[0068] Please refer to Figure 2 and Figure 3 The second electrode assembly 2b has a first surface 21 facing the first electrode assembly 2a, and the first surface 21 is perpendicular to the first direction Z. Viewed along the first direction Z, the second electrode assembly 2b has an overlapping region that overlaps with the first electrode assembly 2a, and a non-overlapping region that does not overlap with the first electrode assembly 2a. The sidewall of the first electrode assembly 2a near the non-overlapping region and the first surface 21 of the non-overlapping region in the second direction Y form a first step 22. The outer casing 1 forms a second step 11 corresponding to the first step 22, and a receiving space 4 is formed between the first step 22 and the second step 11. The surface of the second step 11 facing the interior of the cell 1000, the first step 22, and other walls of the outer casing enclose the receiving space 4.

[0069] The sidewall of the first electrode assembly 2a refers to the sidewall formed by the edges of the multiple anode plates in the first electrode assembly 2a.

[0070] Please refer to Figure 1 The outer shell 1 is a hard shell. The second step 11 is set so that the outline of the outer shell 1 matches the outline of the electrode assembly 2, so as to facilitate the assembly of the electrode assembly 2 and the outer shell 1.

[0071] The battery cell 1000 also includes a filler 3, which is disposed within the receiving space 4. Since the receiving space 4 contains electrolyte, the filler 3 is disposed within the receiving space 4, either filling the receiving space 4 completely or cooperating with the electrolyte. The filler 3 can provide physical support, which facilitates pressure transmission to the area corresponding to the second electrode assembly 2b and the receiving space 4.

[0072] According to the embodiment of the present application, in the battery cell 1000, the length of the second electrode assembly 2b along the second direction Y is greater than the length of the first electrode assembly 2a along the second direction Y, so that the second electrode assembly 2b and the first electrode assembly 2a form a stepped structure, and the contour of the outer shell 1 matches the contour of the electrode assembly 2, so that the battery cell 1000 can adapt to different application scenarios. During the assembly process of the electrode assembly 2 and the outer shell 1, a receiving space 4 is formed between the first step 22 of the electrode assembly 2 and the second step 11 of the outer shell 1. The receiving space 4 can contain electrolyte, which is beneficial for the charge and discharge cycle of the battery cell 1000. By placing the filler 3 in the receiving space 4, the filler 3 can fill the receiving space 4 completely or the filler 3 can cooperate with the electrolyte in the receiving space 4, which can help to effectively transfer the pressure during the manufacturing process of the battery cell 1000 to the area corresponding to the second electrode assembly 2b and the receiving space 4. This can help to increase the stress consistency of this area and other areas of the second electrode assembly 2b, so that the adhesion between the negative electrode sheet and the corresponding separator is higher, reducing the risk of lithium metal deposition on the surface of the negative electrode sheet, and making the battery cell 1000 have higher safety and reliability.

[0073] In one or more of the above optional embodiments, the filler 3 comprises an organic material.

[0074] Organic materials have high toughness and can provide physical support, which is conducive to the effective and uniform transmission of pressure.

[0075] In one or more of the above optional embodiments, the filler 3 includes a mixture of organic and inorganic materials, wherein the inorganic materials account for 1% to 95% of the mass of the mixture.

[0076] Inorganic materials can improve the hardness of filler 3. Simultaneously, inorganic materials possess a certain ability to absorb or transport electrolyte, effectively improving the electrolyte wettability of the area corresponding to the electrode assembly 2 and the containment space 4. The mixture of organic and inorganic materials gives filler 3 not only high mechanical strength and toughness but also the ability to absorb or transport electrolyte. This facilitates the effective transfer of pressure during the cell 1000 process to the area corresponding to the second electrode assembly 2b and the containment space 4, ensuring the consistency of stress distribution between this area and other areas of the second electrode assembly 2b. This improves the electrolyte wettability of the portion corresponding to the electrode assembly 2 and the containment space 4, further effectively improving the interface at the junction of the second electrode assembly 2b and the first electrode assembly 2a.

[0077] If the inorganic material accounts for too small a mass proportion in the mixture, the mixture will have a poor effect in absorbing or transporting electrolyte, and the electrolyte wettability in the corresponding area of ​​the electrode assembly 2 and the containment space 4 will be poor. If the inorganic material accounts for too large a mass proportion in the mixture, the organic material in the mixture will have a too small mass proportion, the mixture will be less tough, and it will not be conducive to uniform pressure transmission.

[0078] By setting the mass ratio of inorganic materials in the mixture to be greater than or equal to 1% and less than or equal to 95%, on the one hand, the effect of the mixture in absorbing and transmitting electrolyte can be improved, and the electrolyte wettability of the corresponding area between the electrode assembly 2 and the containment space 4 can be improved; on the other hand, the mixture has high toughness, which is conducive to uniform pressure transmission.

[0079] In one or more of the above optional embodiments, the inorganic material accounts for 5% to 90% of the mass of the mixture.

[0080] The inorganic material accounts for 5% or more of the mass of the mixture, which further improves the absorption and transport of electrolyte and enhances the electrolyte wettability of the corresponding area between the electrode assembly 2 and the containment space 4. The inorganic material accounts for 90% or less of the mass of the mixture, which further gives the mixture higher toughness and facilitates uniform pressure transmission.

[0081] In one or more of the above optional embodiments, the inorganic material includes at least one of alumina, boehmite, magnesium oxide, magnesium hydroxide, calcium oxide, calcium hydroxide, zinc oxide, barium sulfate, silicon carbide, titanium dioxide, barium titanate, calcium carbonate, silicon oxide, calcium titanate, lithium phosphate, lithium titanium phosphate, lithium aluminum titanium phosphate, lithium nitride, or lithium lanthanum titanate.

[0082] In a mixture of organic and inorganic materials, the inorganic material may be selected from one of the aforementioned materials, or the inorganic material may be selected from a combination of two or more of the aforementioned materials.

[0083] Inorganic materials are selected from at least one of the above materials and have high strength and hardness, good high temperature resistance and high chemical stability. When combined with organic materials, the composite of organic and inorganic materials has high strength and toughness, good high temperature resistance and high chemical stability.

[0084] In one or more of the above optional embodiments, the organic material includes at least one of organosilicon, polyurethane, epoxy resin, polyethylene, polypropylene, ethylene-acrylic acid copolymer, ethylene-vinyl acetate copolymer, polyester, or polyamide.

[0085] In a mixture of organic and inorganic materials, the organic material may be selected from one of the aforementioned materials, or the organic material may be selected from a combination of two or more of the aforementioned materials.

[0086] The organic material is selected from at least one of the above materials and has good flexibility and ductility.

[0087] In one or more of the above optional embodiments, the outer casing 1 includes a first wall 12 and a second wall 13 disposed opposite to each other along a first direction Z. The first wall 12 has a main wall 121 and a stepped wall 122. Along the second direction Y, the stepped wall 122 is located at at least one end of the main wall 121. The stepped wall 122 is recessed relative to the main wall 121 toward the second wall 13. The stepped wall 122 and the main wall 121 are connected by a connecting wall 123 to form a second step 11.

[0088] Please refer to Figure 1 The outer casing 1 may further include a third wall 14, a fourth wall 15, and two fifth walls 16. The third wall 14 and the fourth wall 15 are arranged opposite each other along the second direction Y. The third wall 14 connects the main wall 121 and the second wall 13, and the fourth wall 15 connects the step wall 122 and the second wall 13. The two fifth walls 16 are arranged opposite each other along the third direction X. One end of the fifth wall 16 is connected to the second wall 13, and the other end of the fifth wall 16 is connected to the main wall 121, the step wall 122, and the connecting wall 123. The third direction X, the second direction Y, and the first direction Z are all perpendicular to each other.

[0089] In some embodiments, the first wall 12 can be an integrally formed structure. For example, the stepped wall 122 is recessed relative to the main wall 121 toward the second wall 13, and the first wall 12 can be formed by stamping during the manufacturing process of the outer shell 1. Alternatively, the first wall 12 can be an integrally injection molded structure.

[0090] The first wall 12 can be formed into the second step 11 by stamping or injection molding, which is convenient for processing and manufacturing. The first wall 12 has high overall strength.

[0091] The second electrode assembly 2b is disposed between the step wall 122 and the second wall 13, and the first electrode assembly 2a is disposed between the main body wall 121 and the second electrode assembly 2b. The first electrode assembly 2a, the second electrode assembly 2b, the connecting wall 123 and the main body wall 121 form an accommodating space 4.

[0092] The first wall 12 and the second wall 13 are spaced apart along the first direction Z. After the electrode assembly 2 is assembled with the outer shell 1, along the first direction Z, the second electrode assembly 2b is disposed between the stepped wall 122 and the second wall 13, that is, the second electrode assembly 2b is located between the second wall 13 and the first wall 12; along the first direction Z, the first electrode assembly 2a is disposed between the main body wall 121 and the second electrode assembly 2b.

[0093] The second electrode assembly 2b is disposed between the stepped wall 122 and the second wall 13, and the first electrode assembly 2a is disposed between the main body wall 121 and the second electrode assembly 2b, so that the outer shell 1 and the electrode assembly 2 can match the contours, so that the outer shell 1 can protect the electrode assembly 2 and reduce the risk of damage to the electrode assembly 2.

[0094] In one or more of the above optional embodiments, along the first direction Z, the second electrode assembly 2b has a first region 23 that overlaps with the projection of the accommodating space 4, the projected area of ​​the first region 23 is S1, and the projected area of ​​the second electrode assembly 2b is S2, satisfying that 0.001≤S1 / S2≤0.2.

[0095] With the first direction Z as the projection direction, on the projection plane perpendicular to the first direction Z, the area of ​​the orthographic projection of the first region 23 is S1, and the area of ​​the orthographic projection of the second electrode assembly 2b is S2.

[0096] If the ratio of the projected area of ​​the first region 23 to the projected area of ​​the second electrode assembly 2b is too small, the volume of the accommodating space 4 will be too small, which is not conducive to the assembly of the electrode assembly 2 and the outer shell 1, and the pressure transmission effect between the filler 3 and the first region 23 will be poor. If the ratio of the projected area of ​​the first region 23 to the projected area of ​​the second electrode assembly 2b is too large, the volume of the accommodating space 4 will be too large, the utilization rate of the internal space of the outer shell 1 will be low, and the energy density of the battery cell 1000 will be low.

[0097] The first region 23 corresponds to the boundary region between the second electrode assembly 2b and the first electrode assembly 2a. When viewed along the first direction Z, the filler 3 at least partially overlaps with the first region 23. By setting the ratio of the projected area of ​​the first region 23 to the projected area of ​​the second electrode assembly 2b to be greater than or equal to 0.001 and less than or equal to 0.2, on the one hand, it facilitates the assembly of the electrode assembly 2 and the outer shell 1, facilitates the transmission of pressure between the filler 3 and the first region 23, and facilitates a greater adhesion between the negative electrode sheet of the first region 23 and the separator, thereby reducing the risk of lithium metal deposition on the surface of the negative electrode sheet of the first region 23; on the other hand, the internal space utilization of the outer shell 1 is high, and the cell 1000 has a high energy density.

[0098] For example, the ratio of the projected area of ​​the first region 23 to the projected area of ​​the second electrode assembly 2b can be, but is not limited to, 0.001, 0.005, 0.01, 0.05, 0.1, 0.15, 0.2, etc.

[0099] For example, 0.01≤S1 / S2≤0.15. S1 / S2≥0.01 further facilitates the assembly of the electrode assembly 2 and the housing 1, facilitates the transmission of pressure between the filler 3 and the first region 23, and is beneficial to the greater adhesion between the negative electrode sheet and the separator in the first region 23, thereby reducing the risk of lithium metal deposition on the surface of the negative electrode sheet in the first region 23; S1 / S2≤0.15 further makes the internal space utilization of the housing 1 higher, and the cell 1000 has a higher energy density.

[0100] In some embodiments, along the second direction Y, the end of the first region 23 may extend beyond the receiving space 4. For example, along the first direction Z, the first region 23 has a first overlapping region that overlaps with a portion of the first positive electrode sheet, and a second overlapping region that overlaps with a portion of the stepped wall 122.

[0101] In some embodiments, please refer to Figure 4 The second electrode assembly 2b also includes a second region 24 and a third region 25. The second region 24, the first region 23 and the third region 25 are distributed along the second direction Y. The first region 23 connects the second region 24 and the third region 25. Along the first direction Z, the projection of the second region 24 partially overlaps with the main body wall 121, and the projection of the third region 25 at least partially overlaps with the step wall 122.

[0102] In one or more of the above optional embodiments, along the first direction Z, the projected area of ​​the first electrode assembly 2a is S3 and the projected area of ​​the second electrode assembly 2b is S2, satisfying that 0.2≤S3 / S2≤0.9.

[0103] With the first direction Z as the projection direction, the area of ​​the orthographic projection of the first electrode assembly 2a is S3, and the area of ​​the orthographic projection of the second electrode assembly 2b is S2.

[0104] If the ratio of the projected area of ​​the first electrode assembly 2a to the projected area of ​​the second electrode assembly 2b is too large, the size difference between the first electrode assembly 2a and the second electrode assembly 2b will be too small, making processing and manufacturing more difficult. If the ratio of the projected area of ​​the first electrode assembly 2a to the projected area of ​​the second electrode assembly 2b is too small, the size difference between the first electrode assembly 2a and the second electrode assembly 2b will be too large, which is not conducive to achieving the design goal of increasing the energy density of the battery cell by flexibly utilizing space. Furthermore, if the size difference between the first electrode assembly 2a and the second electrode assembly 2b is too large, the area of ​​the junction region, i.e., the first region 23, of the first electrode assembly 2a and the second electrode assembly 2b will be larger, and the problem of uneven force distribution will be more serious.

[0105] By setting the ratio of the projected area of ​​the first electrode assembly 2a to the projected area of ​​the second electrode assembly 2b to be greater than or equal to 0.2 and less than or equal to 0.9, on the one hand, the processing and manufacturing difficulty is lower; on the other hand, the battery cell 1000 has a higher energy density, reducing the uneven stress distribution in the interface area between the first electrode assembly 2a and the second electrode assembly 2b.

[0106] For example, the ratio of the projected area of ​​the first electrode assembly 2a to the projected area of ​​the second electrode assembly 2b can be, but is not limited to, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, etc.

[0107] For example, 0.3 ≤ S3 / S2 ≤ 0.8. S3 / S2 ≥ 0.3 further reduces the difficulty of processing and manufacturing; S3 / S2 ≤ 0.8 further enables the cell 1000 to have a higher energy density.

[0108] In one or more of the above optional embodiments, the filler 3 is connected to the second electrode assembly 2b and / or the housing 1.

[0109] In some embodiments, the filler 3 can be connected to the second electrode assembly 2b at the receiving space 4, that is, the filler 3 is connected to the first region 23 of the second electrode assembly 2b; in the cell 1000 process, when the second electrode assembly 2b is subjected to a force toward the first electrode assembly 2a, the filler 3 can provide physical support, which is conducive to pressure transmission and improves the force consistency of the first region 23 and other regions of the second electrode assembly 2b.

[0110] In some embodiments, the filler 3 can be connected to the housing 1 at the receiving space 4. During the cell 1000 process, when the second electrode assembly 2b is subjected to a force toward the first electrode assembly 2a, the filler 3 can provide physical support, which is conducive to pressure transmission and ensures the consistency of force on the first region 23 and other regions of the second electrode assembly 2b.

[0111] In some embodiments, at the receiving space 4, the filler 3 can be connected to the second electrode assembly 2b and the housing 1. The filler 3 is supported between the first region 23 and the housing 1. In the cell 1000 process, when the second electrode assembly 2b is subjected to a force toward the first electrode assembly 2a, the filler 3 can provide physical support, which is conducive to pressure transmission and ensures the consistency of force on the first region 23 and other regions of the second electrode assembly 2b.

[0112] By connecting the filler 3 to the second electrode assembly 2b and / or the housing 1, pressure transmission is facilitated, and the stress consistency between the corresponding area of ​​the electrode assembly 2 and the receiving space 4 and other areas of the second electrode assembly 2b is ensured.

[0113] In one or more of the above optional embodiments, the outer casing 1 is a rigid casing, and the battery cell 1000 is a rigid-cased battery cell. Exemplarily, the outer casing 1 can be a steel casing, an aluminum casing, a hard plastic casing, etc.

[0114] In one or more of the above optional embodiments, along the first direction Z, the minimum distance between the filler 3 and the outer shell 1 is H, which satisfies that 0≤H≤5mm.

[0115] When the outer shell 1 is a hard shell, if the distance between the filler 3 and the outer shell 1 along the first direction Z is too large, the pressure on the outer shell 1 cannot be transmitted to the first region 23.

[0116] The outer shell 1 has a certain elasticity. By setting the distance between the filler 3 and the outer shell 1 along the first direction Z to be greater than or equal to 0 and less than or equal to 5 mm, it is beneficial for the pressure on the outer shell 1 to be transmitted to the first region 23 along the first direction.

[0117] For example, H can be, but is not limited to, 0, 0.2mm, 0.4mm, 0.6mm, 0.8mm, 1mm, 1.2mm, 1.4mm, 1.6mm, 1.8mm, 2mm, 2.2mm, 2.4mm, 2.6mm, 2.8mm, 3mm, 3.2mm, 3.5mm, 3.7mm, 4mm, 4.2mm, 4.5mm, 4.7mm, 5mm, etc.

[0118] In one or more of the above optional embodiments, 0.4mm ≤ H ≤ 3.5mm.

[0119] When H≥0.4mm, it facilitates the assembly of electrode assembly 2 and housing 1 and can accommodate processing errors; when H≤3.5mm, the distance between housing 1 and filler 3 is small, which further facilitates the transmission of pressure on housing 1 to the first region 23.

[0120] Based on the aforementioned battery cell 1000, this application embodiment also provides an electrical device that includes the battery cell 1000 provided according to any of the above embodiments.

[0121] The aforementioned battery cell 1000 has high safety and reliability, which makes the electrical equipment made of the battery cell 1000 have high safety and reliability.

[0122] This application also provides a method for manufacturing a battery cell 1000, used to manufacture the battery cell 1000 according to any of the above embodiments. The method for manufacturing the battery cell 1000 includes: S100, provides electrode assembly 2; S200, provides housing 1; S300, a slurry is applied to the second step 11 of the outer casing 1, or a slurry is applied to the first step 22 of the electrode assembly 2, and the electrode assembly 2 is housed in the outer casing 1, such that the slurry is located in the housing space 4 between the first step 22 and the second step 11, and the slurry solidifies to form a filler 3.

[0123] The battery cell 1000 manufactured by the above-described method has high safety and reliability.

[0124] In one or more of the above optional embodiments, the initial construction viscosity of the slurry is greater than or equal to 30,000 Pa·s.

[0125] The initial application viscosity of the slurry refers to the viscosity of the slurry before it is applied to the outer casing 1 or the electrode assembly 2. The slurry has a certain viscosity at the beginning, which facilitates the connection between the slurry and the outer casing 1 or the electrode assembly 2, and is beneficial for the assembly of the battery cell 1000.

[0126] By setting the initial construction viscosity of the slurry to be greater than or equal to 30,000 Pa·s, the slurry has poor fluidity, which reduces the risk of the slurry flowing into the electrode assembly 2 during the preparation of the battery cell 1000 and affecting the capacity of the battery cell 1000.

[0127] In one or more of the above optional embodiments, step "S300, applying slurry to the second step 11 of the outer shell 1, or applying slurry to the first step 22 of the electrode assembly 2, accommodating the electrode assembly 2 within the outer shell 1, such that the slurry is located in the accommodating space 4 between the first step 22 and the second step 11, and the slurry solidifies to form a filler 3" includes: heating and melting the slurry, applying the melted slurry to the second step 11 or the first step 22, accommodating the electrode assembly 2 within the outer shell 1, and solidifying the slurry after cooling to form a filler 3.

[0128] Before assembling the electrode assembly 2 with the housing 1, a slurry is first applied to the surface of the first step 22 of the housing 1 that forms the receiving space 4, or a slurry is applied to the second step 11 of the electrode assembly 2, and then the electrode assembly 2 is housed in the housing 1. The slurry hardens to form the filler 3 after the temperature drops to room temperature.

[0129] In some embodiments, after the slurry melts, it can have good viscosity, resulting in a high bonding force between the slurry and the housing 1 or the electrode assembly 2, which is beneficial for the connection between the slurry and the housing 1 or the electrode assembly 2.

[0130] The slurry is melted by heat, which melts the organic materials in the slurry, making it easier for the slurry to connect with the outer shell 1 or the electrode assembly 2. After the temperature drops to room temperature, the organic materials harden again. Through the material hardening process, the filler 3 is placed in the receiving space 4. The filler 3 has high hardness, which is conducive to pressure transmission.

[0131] In one or more of the above optional embodiments, the heating temperature of the slurry is 50°C to 300°C.

[0132] If the heating temperature of the slurry is too low, the slurry will not melt sufficiently, which is not conducive to the assembly of the slurry with the outer shell 1 or the electrode assembly 2; if the heating temperature of the slurry is too high, energy will be wasted, and the slurry has high fluidity and will easily flow into the interior of the electrode assembly 2.

[0133] By setting the heating temperature of the slurry to be greater than or equal to 50°C and less than or equal to 300°C, on the one hand, it can be adapted to melting a variety of materials. The slurry is melted and coated onto the outer shell 1 or the electrode assembly 2, which is beneficial to the preparation of the battery cell 1000. On the other hand, it can save energy. The slurry has poor fluidity, which reduces the risk of it flowing into the electrode assembly 2.

[0134] For example, the heating temperature of the slurry can be, but is not limited to, 50°C, 80°C, 100°C, 120°C, 160°C, 200°C, 240°C, 260°C, 300°C, etc.

[0135] For example, the heating temperature of the slurry can be 80°C to 260°C.

[0136] In one or more of the above optional embodiments, a slurry is applied to the second step 11 of the housing 1, or a slurry is applied to the first step 22 of the electrode assembly 2, and the electrode assembly 2 is housed in the housing 1, such that the slurry is located in the housing space 4 between the first step 22 and the second step 11, and the slurry solidifies to form a filler 3. This includes: applying the slurry to the second step 11, or applying the slurry to the first step 22, and housing the electrode assembly 2 in the housing 1, and causing the slurry to undergo a chemical reaction and solidify to form the filler 3 by heating the battery cell 1000 or by catalysis by a catalyst in the slurry.

[0137] The heating of the battery cell 1000 can be completed in the drying process. That is, when the electrode assembly 2 is housed in the outer casing 1, the slurry may not be solidified. When the battery cell 1000 is transported to the drying process, the slurry undergoes a chemical reaction and solidifies to form the filler 3 during the drying process.

[0138] In some embodiments, a catalyst may be mixed into the slurry, which then undergoes a chemical reaction and solidifies to form filler 3.

[0139] The organic materials in the slurry undergo chemical reactions under high temperature or the action of a catalyst, and produce cross-linked structures, which leads to hardening of the slurry and gives filler 3 a high hardness.

[0140] The features and performance of the battery cell 1000 of this application are further described in detail below with reference to embodiments.

[0141] The battery cells 1000 in each embodiment and comparative example were prepared and tested in the following directions.

[0142] 1. Preparation of Cell 1000 1.1 Preparation of the positive electrode sheet The active material lithium cobalt oxide, conductive agent (conductive carbon (super P)) and binder (polyvinylidene fluoride (PVDF)) are thoroughly mixed in an N-methylpyrrolidone solvent system at a weight ratio of 94:3:3. The mixture is then coated onto aluminum foil, dried, and cold-pressed to obtain the positive electrode sheet.

[0143] 1.2 Preparation of negative electrode sheet The active material artificial graphite, conductive agent (conductive carbon (super P)), binder (styrene-butadiene rubber (SBR)) and thickener (sodium carboxymethyl cellulose (CMC)) are thoroughly mixed in a deionized water solvent system at a weight ratio of 97:1:1.5:0.5. The mixture is then coated onto copper foil, dried, and cold-pressed to obtain the negative electrode sheet.

[0144] 1.3 Preparation of Electrode Component 2 The positive electrode, separator, and negative electrode are stacked in sequence, with the separator positioned between the positive and negative electrode to provide isolation, resulting in a first electrode assembly 2a and a second electrode assembly 2b. The first electrode assembly 2a and the second electrode assembly 2b are then hot-pressed together to form a stepped electrode assembly 2 structure.

[0145] 1.4 Cell 1000 Assembly The electrode assembly 2 is placed in a steel shell, and the space 4 between the steel shell and the electrode assembly 2 is filled with filler 3. Then, electrolyte is injected and it is sealed. After formation, the final battery cell 1000 is produced.

[0146] 2. Testing Methods 2.1 Inorganic material ratio test Disassemble cell 1000, remove the organic and inorganic filler 3, and heat it in a muffle furnace at 500℃ for 12 hours. Weigh the cells before and after heating, and record them as M0 and M1 respectively. The formula for calculating the proportion of inorganic material is as follows: (M1 / M0)*100%.

[0147] 2.2 Viscosity test of filler 3 For chemically hardened materials: Take 500g of filler 3 containing organic and inorganic materials, and use a rotational viscometer to measure and verify the viscosity of filler 3. Take the average value of 3 tests and record it as the final viscosity value. For physically hardened materials: Take 500g of filler 3, which is composed of organic and inorganic materials, heat it to 100℃, and use a rotational viscometer to measure and verify the viscosity of filler 3. Take the average value of 3 tests and record it as the final viscosity value.

[0148] 2.3 Cell 1000 Interface Test Take 1000 finished cells after formation, fully charge them at 0.5C, disassemble them, observe the black spots and lithium plating on the negative electrode interface, and take photos to record the observations.

[0149] 3. Comparative Examples and Implementation Examples Comparative Example 1 The first electrode assembly 2a and the second electrode assembly 2b were prepared according to the above method. After hot pressing and bonding, liquid injection and formation were carried out. The formation temperature was 75℃, the pressure was 1.0MPa, and the formation time was 60min, resulting in the finished battery cell 1000.

[0150] Example 1 The first electrode assembly 2a and the second electrode assembly 2b were prepared according to the above method. After hot pressing and bonding, an organosilicon and alumina filler 3 was coated in the accommodating space 4 formed by the steel shell and the composite electrode assembly 2. The mass ratio of alumina in the filler 3 was 0.5%, and the viscosity of the filler 3 was 29000 mPa·s. Then, liquid injection and formation were carried out. The formation temperature was 75℃, the pressure was 1.0 MPa, and the formation time was 60 min, resulting in the finished battery cell 1000.

[0151] Example 2 The first electrode assembly 2a and the second electrode assembly 2b were prepared according to the above method. After hot pressing and bonding, an organosilicon and alumina filler 3 was coated in the accommodating space 4 formed by the steel shell and the composite electrode assembly 2. The mass ratio of alumina in the filler 3 was 1%, and the viscosity of the filler 3 was 31000 mPa·s. Then, liquid injection and formation were carried out. The formation temperature was 75℃, the pressure was 1.0 MPa, and the formation time was 60 min to obtain the finished battery cell 1000.

[0152] Example 3 The first electrode assembly 2a and the second electrode assembly 2b were prepared according to the above method. After hot pressing and bonding, an organosilicon and alumina filler 3 was coated in the accommodating space 4 formed by the steel shell and the composite electrode assembly 2. The mass ratio of alumina in the filler 3 was 5%, and the viscosity of the filler 3 was 31000 mPa·s. Then, liquid injection and formation were carried out. The formation temperature was 75℃, the pressure was 1.0 MPa, and the formation time was 60 min to obtain the finished battery cell 1000.

[0153] Example 4 The first electrode assembly 2a and the second electrode assembly 2b were prepared according to the above method. After hot pressing and bonding, an organosilicon and alumina filler 3 was coated in the accommodating space 4 formed by the steel shell and the composite electrode assembly 2. The mass ratio of alumina in the filler 3 was 40%, and the viscosity of the filler 3 was 30000 mPa·s. Then, liquid injection and formation were carried out. The formation temperature was 75℃, the pressure was 1.0 MPa, and the formation time was 60 min to obtain the finished battery cell 1000.

[0154] Example 5 The first electrode assembly 2a and the second electrode assembly 2b were prepared according to the above method. After hot pressing and bonding, an organosilicon and alumina filler 3 was coated in the accommodating space 4 formed by the steel shell and the composite electrode assembly 2. The mass ratio of alumina in the filler 3 was 50%, and the viscosity of the filler 3 was 54000 mPa·s. Then, liquid injection and formation were carried out. The formation temperature was 75℃, the pressure was 1.0 MPa, and the formation time was 60 min to obtain the finished battery cell 1000.

[0155] Example 6 The first electrode assembly 2a and the second electrode assembly 2b were prepared according to the above method. After hot pressing and bonding, an organosilicon and alumina filler 3 was coated in the accommodating space 4 formed by the steel shell and the composite electrode assembly 2. The mass ratio of alumina in the filler 3 was 70%, and the viscosity of the filler 3 was 154000 mPa·s. Then, liquid injection and formation were carried out. The formation temperature was 75℃, the pressure was 1.0 MPa, and the formation time was 60 min to obtain the finished battery cell 1000.

[0156] Example 7 The first electrode assembly 2a and the second electrode assembly 2b were prepared according to the above method. After hot pressing and bonding, an organosilicon and alumina filler 3 was coated in the accommodating space 4 formed by the steel shell and the composite electrode assembly 2. The mass ratio of alumina in the filler 3 was 90%, and the viscosity of the filler 3 was 200000 mPa·s. Then, liquid injection and formation were carried out. The formation temperature was 75℃, the pressure was 1.0 MPa, and the formation time was 60 min to obtain the finished battery cell 1000.

[0157] Example 8 The first electrode assembly 2a and the second electrode assembly 2b were prepared according to the above method. After hot pressing and bonding, an organosilicon and alumina filler 3 was coated in the accommodating space 4 formed by the steel shell and the composite electrode assembly 2. The mass ratio of alumina in the filler 3 was 95%, and the viscosity of the filler 3 was 210000 mPa·s. Then, liquid injection and formation were carried out. The formation temperature was 75℃, the pressure was 1.0 MPa, and the formation time was 60 min, resulting in the finished battery cell 1000.

[0158] Example 9 The first electrode assembly 2a and the second electrode assembly 2b were prepared according to the above method. After hot pressing and bonding, an organosilicon and alumina filler 3 was coated in the accommodating space 4 formed by the steel shell and the composite electrode assembly 2. The mass ratio of alumina in the filler 3 was 96%, and the viscosity of the filler 3 was 220000 mPa·s. Then, liquid injection and formation were carried out. The formation temperature was 75℃, the pressure was 1.0 MPa, and the formation time was 60 min, resulting in the finished battery cell 1000.

[0159] Example 10 The first electrode assembly 2a and the second electrode assembly 2b were prepared according to the above method. After hot pressing and bonding, an organosilicon and boehmite filler 3 was coated in the containment space 4 formed by the steel shell and the composite electrode assembly 2. The mass ratio of boehmite in the filler 3 was 50%, and the viscosity of the filler 3 was 52000 mPa·s. Then, liquid injection and formation were carried out. The formation temperature was 75℃, the pressure was 1.0 MPa, and the formation time was 60 min to obtain the finished battery cell 1000.

[0160] Example 11 The first electrode assembly 2a and the second electrode assembly 2b were prepared according to the above method. After hot pressing and bonding, an organosilicon and lithium titanium aluminum phosphate filler 3 was coated in the space 4 formed by the steel shell and the composite electrode assembly 2. The mass ratio of lithium titanium aluminum phosphate in the filler 3 was 50%, and the viscosity of the filler 3 was 55000 mPa·s. Then, liquid injection and formation were carried out. The formation temperature was 75℃, the pressure was 1.0 MPa, and the formation time was 60 min to obtain the finished battery cell 1000.

[0161] Example 12 The first electrode assembly 2a and the second electrode assembly 2b were prepared according to the above method. After hot pressing and bonding, epoxy resin and alumina filler 3 were coated in the accommodating space 4 formed by the steel shell and the composite electrode assembly 2. The mass ratio of alumina in filler 3 was 50%, and the viscosity of filler 3 was 56000 mPa·s. Then, liquid injection and formation were carried out. The formation temperature was 75℃, the pressure was 1.0 MPa, and the formation time was 60 min to obtain the finished battery cell 1000.

[0162] Example 13 The first electrode assembly 2a and the second electrode assembly 2b were prepared according to the above method. After hot pressing and bonding, an ethylene-vinyl acetate copolymer and alumina filler 3 were coated in the accommodating space 4 formed by the steel shell and the composite electrode assembly 2. The mass ratio of alumina in the filler 3 was 50%, and the viscosity of the filler 3 was 52000 mPa·s. Then, liquid injection and formation were carried out. The formation temperature was 75℃, the pressure was 1.0 MPa, and the formation time was 60 min to obtain the finished battery cell 1000.

[0163] The battery cells 1000 of the above comparative examples and embodiments were tested using the above testing methods, and the results are shown in Table 1.

[0164] Table 1

[0165] As shown in Table 1, in Comparative Example 1, the accommodating space 4 is not filled with filler 3, which makes the first region 23 and other regions of the second electrode assembly 2b have uneven stress. This results in a low adhesion between the negative electrode sheet of the first region 23 and the corresponding separator. After the battery cell 1000 is charged, metal ions are easily deposited on the surface of the negative electrode sheet of the second electrode assembly 2b, resulting in obvious black spots or purple spots on the surface of the negative electrode sheet of the second electrode assembly 2b.

[0166] However, in embodiments 1-13, by providing a filler 3 in the accommodating space 4, the filler 3 can transmit pressure, ensuring the consistency of force between the first region 23 and other regions of the second electrode assembly 2b, so that the area of ​​black spots or purple spots on the surface of the negative electrode sheet of the second electrode assembly 2b is smaller, significantly improving the black spots or purple spots, and making the battery cell 1000 have higher safety performance.

[0167] Furthermore, in Examples 2-8 and 10-13, the inorganic material accounts for more than or equal to 1% and less than or equal to 95% of the mass in the mixture. The filler 3 has high toughness and hardness, and can effectively and uniformly conduct pressure. At the same time, the filler 3 has a certain function of absorbing or transporting electrolyte, which can effectively improve the electrolyte wettability of the area where the second electrode assembly 2b overlaps with the accommodating space 4, further effectively improve the interface at the junction of the second electrode assembly 2b and the first electrode assembly 2a, and significantly improve the black spots or purple spots on the negative electrode sheet of the second electrode assembly 2b.

[0168] Although this application has been described with reference to preferred embodiments, various modifications can be made thereto and components can be replaced with equivalents without departing from the scope of this application. In particular, the technical features mentioned in the various embodiments can be combined in any manner, provided there is no structural conflict. 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: shell; An electrode assembly, housed within a housing, comprises a first electrode assembly and a second electrode assembly, which are stacked along a first direction. Along a second direction, the length of the second electrode assembly is greater than the length of the first electrode assembly. The second electrode assembly has a first surface facing the first electrode assembly. Viewed along the first direction, the second electrode assembly has an overlapping region that overlaps with the first electrode assembly and a non-overlapping region that does not overlap with the first electrode assembly. A first step is formed between the sidewall of the first electrode assembly near the non-overlapping region and the first surface of the non-overlapping region in the second direction. The housing forms a second step corresponding to the first step, and a receiving space is formed between the first step and the second step. The second direction is perpendicular to the first direction; A filler, disposed in the receiving space, wherein the filler is a solid.

2. The battery cell according to claim 1, characterized in that, The filler includes organic materials.

3. The battery cell according to claim 2, characterized in that, The filler comprises a mixture of organic and inorganic materials, wherein the inorganic materials account for 1% to 95% of the mass of the mixture.

4. The battery cell according to claim 3, characterized in that, The inorganic material accounts for 5% to 90% of the mass of the mixture.

5. The battery cell according to claim 3, characterized in that, The inorganic material includes at least one of alumina, boehmite, magnesium oxide, magnesium hydroxide, calcium oxide, calcium hydroxide, zinc oxide, barium sulfate, silicon carbide, titanium dioxide, barium titanate, calcium carbonate, silicon oxide, calcium titanate, lithium phosphate, lithium titanium phosphate, lithium aluminum titanium phosphate, lithium nitride, or lithium lanthanum titanate.

6. The battery cell according to claim 2, characterized in that, The organic material includes at least one of organosilicon, polyurethane, epoxy resin, polyethylene, polypropylene, ethylene-acrylic acid copolymer, ethylene-vinyl acetate copolymer, polyester, or polyamide.

7. The battery cell according to claim 1, characterized in that, The outer casing includes a first wall and a second wall disposed opposite to each other along the first direction. The first wall has a main wall and a stepped wall. Along the second direction, the stepped wall is located at at least one end of the main wall. The stepped wall is recessed relative to the main wall toward the second wall. The stepped wall is connected to the main wall by a connecting wall to form the second step. The second electrode assembly is disposed between the stepped wall and the second wall, and the first electrode assembly is disposed between the main body wall and the second electrode assembly. The first electrode assembly, the second electrode assembly, the connecting wall, and the main body wall form the accommodating space.

8. The battery cell according to claim 7, characterized in that, Along the first direction, the second electrode assembly has a first region that overlaps with the projection of the accommodating space, the projected area of ​​the first region is S1, and the projected area of ​​the second electrode assembly is S2, satisfying that 0.001≤S1 / S2≤0.

2.

9. The battery cell according to claim 1, characterized in that, Along the first direction, the projected area of ​​the first electrode assembly is S3, and the projected area of ​​the second electrode assembly is S2, satisfying 0.2≤S3 / S2≤0.

9.

10. The battery cell according to claim 1, characterized in that, The filler is connected to the second electrode assembly and / or the housing.

11. The battery cell according to claim 1, characterized in that, Along the first direction, the minimum distance between the filler and the outer shell is H, which satisfies 0≤H≤5mm.

12. The battery cell according to claim 11, characterized in that, 0.4mm≤H≤3.5mm.

13. An electrical appliance, characterized in that, Includes the battery cell as described in any one of claims 1-12.

14. A method for manufacturing a battery cell, used to manufacture a battery cell as described in any one of claims 1-12, characterized in that, The method for manufacturing the battery cell includes: Provide the electrode assembly; Provide the housing; A slurry is applied to the second step of the housing or to the first step of the electrode assembly, and the electrode assembly is housed within the housing such that the slurry is located in the accommodating space between the first step and the second step, and the slurry solidifies to form the filler.

15. The method for manufacturing a battery cell according to claim 14, characterized in that, The initial construction viscosity of the slurry is greater than or equal to 30,000 Pa·s.

16. The method for manufacturing a battery cell according to claim 14, characterized in that, The process involves applying a slurry to the second step of the housing or to the first step of the electrode assembly, thereby housing the electrode assembly within the housing such that the slurry is located in the accommodating space between the first and second steps, and the slurry solidifies to form the filler. This includes: The slurry is heated and melted, and the melted slurry is applied to the second step or the first step. The electrode assembly is housed in the outer shell, and the slurry solidifies after cooling to form the filler.

17. The method for manufacturing a battery cell according to claim 16, characterized in that, The heating temperature of the slurry is 50℃~300℃.

18. The method for manufacturing a battery cell according to claim 14, characterized in that, The process involves applying a slurry to the second step of the housing or to the first step of the electrode assembly, thereby housing the electrode assembly within the housing such that the slurry is located in the accommodating space between the first and second steps, and the slurry solidifies to form the filler. This includes: The electrode assembly is housed within the housing by applying a slurry to the second step or the first step, and by heating the battery cell or by catalyzing the slurry with a catalyst, the slurry undergoes a chemical reaction and solidifies to form a filler.

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