Battery cell and electric equipment

Abstract

The embodiment of the invention provides a battery cell and electric equipment, the battery cell comprises a shell, an electrode assembly, a bonding piece and a filling piece, the electrode assembly comprises a first pole piece group and a second pole piece group which are laminated along a first direction, and the size of the first pole piece group along a second direction is smaller than that of the second pole piece group along the second direction; in the first direction, the second pole piece group is provided with a first surface facing the first pole piece group, the second pole piece group comprises a second part which is not overlapped with the first pole piece group, and the side wall, close to the second part, of the first pole piece group in the second direction and the first surface of the second part form a first step; the housing forms a second step corresponding to the first step. The bonding piece is bonded to the first step, and a containing space is formed between the bonding piece and the second step in the second direction. The filling piece is arranged in the containing space. The risk that metal ions are separated out in the circulation process of the battery cell can be reduced, and the safety and reliability of the battery cell are improved. The bonding member can prevent the filling member from flowing into the electrode assembly.

Description

Technical Field

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

[0002] With the rapid development of electronic information technology, various electronic devices are also moving towards intelligence and multi-functions, and the requirements for battery safety are becoming higher and higher.

[0003] In a stepped battery cell, multiple electrode groups of different sizes are arranged in the outer casing. During some processes of battery cell preparation, the battery cell is subjected to external pressure. There is uneven force at the junction and other areas of electrode groups of different sizes, resulting in poor interface at the junction. There may be a risk of metal ion precipitation during the cycle process, affecting the safety and reliability of the battery cell. Summary of the invention

[0004] The present application provides a battery cell and electrical equipment, which can improve the safety and reliability of the battery cell.

[0005] In the first aspect, the embodiment of the present application provides a battery cell, the battery cell includes a shell, an electrode assembly, an adhesive and a filling member, the electrode assembly is accommodated in the shell, and the electrode assembly is a laminated structure; the electrode assembly includes a first electrode group and a second electrode group, the first electrode group and the second electrode group are stacked along the first direction, the size of the first electrode group along the second direction is smaller than the size of the second electrode group along the second direction; along the first direction, the second electrode group has a first surface facing the first electrode group, the second electrode group includes a first part overlapping with the projection of the first electrode group, and a second part not overlapping with the first electrode group, the side wall of the first electrode group close to the second part in the second direction and the first surface of the second part form a first step; the shell is formed with a second step corresponding to the first step. The adhesive is adhered to the first step, and along the second direction, a holding space is formed between the adhesive and the second step. The filling member is arranged in the holding space. The first direction is parallel to the thickness direction of the electrode assembly, and the first direction is perpendicular to the second direction.

[0006] In the above technical solution, by accommodating the electrode assembly in the shell, the electrode assembly is a laminated structure, which can make the electrode assembly occupy a larger space in the shell, which is beneficial to improve the energy density of the battery cell. By making the side wall of the first electrode plate group close to the second part in the second direction and the first surface of the second part form a first step, and the shell forms a second step corresponding to the first step, when the battery cell is installed in the battery compartment of the electrical equipment, other components in the battery compartment can be placed at the second step, thereby improving the space utilization of the battery compartment, and further improving the compactness of the internal structure of the electrical equipment. By making the filler be arranged in the accommodating space, the filler fills the accommodating space or the filler cooperates with the electrolyte in the accommodating space, the external pressure on the shell is transmitted to the area corresponding to the second electrode plate group and the accommodating space, so that the pressure consistency of this area and other areas of the second electrode plate group is better, which can reduce the risk of metal ion precipitation in the battery cell during the cycle and improve the safety and reliability of the battery cell. By making the adhesive adhere to the first step, a receiving space is formed between the adhesive and the second step along the second direction, and the filler is arranged in the receiving space, so that when the filler is filled in the receiving space in a fluid state, the adhesive can block the filler from flowing into the interior of the electrode assembly, thereby preventing the filler from interfering with the internal chemical system of the battery cell, thereby reducing the possibility of the filler affecting the volume of the electrode assembly and the spacing distance between the pole pieces, and can also play a buffering role when subjected to external force, thereby reducing the possibility of the electrode assembly being directly damaged by the force.

[0007] In some embodiments of the present application, the adhesive includes a first section, a second section and a third section, the first section is adhered to the side of the first pole piece group away from the second pole piece group along the first direction, the second section is adhered to the second part, and the third section connects the first section and the second section.

[0008] In the above technical solution, by making the first section adhere to the side of the first electrode group away from the second electrode group along the first direction, and the second section adhere to the second part, the adhesion area of ​​the adhesive and the electrode assembly can be larger, the connection strength of the adhesive and the electrode assembly is higher, and the possibility of the adhesive detaching from the electrode assembly is reduced. By making the second section adhere to the second part, and the third section connects the first section and the second section, the projection of the third section in the second direction can cover the end face of the first electrode group along the second direction, thereby further reducing the possibility of the filler flowing from the end face of the first electrode group into the first electrode group or between the first electrode group and the second electrode group.

[0009] In some embodiments of the present application, along the first direction, the projection area of ​​the first segment is S1, and the projection area of ​​the first pole piece group is S2, satisfying 10%≤S1 / S2≤100%.

[0010] In the above technical solution, by making the projected area S1 of the first section and the projected area S2 of the first electrode plate group satisfy 10%≤S1 / S2≤100% along the first direction, the connection area between the first section and the first electrode plate group can be made larger, the connection strength can be made greater, the possibility of the adhesive being separated from the first electrode plate group can be reduced, and the possibility of the filling member flowing into the interior of the electrode assembly can be reduced.

[0011] In some embodiments of the present application, 20%≤S1 / S2≤90%.

[0012] In the above technical scheme, when S1 / S2 is greater than or equal to 20%, the connection area between the first section and the first electrode group can be further increased, the connection strength can be increased, the possibility of the adhesive being separated from the first electrode group can be further reduced, and the possibility of the filling member flowing into the electrode assembly can be reduced; when S1 / S2 is less than or equal to 90%, the space occupied by the first section can be smaller, so that there is more space in the outer shell for accommodating the electrolyte, which is beneficial to extending the service life of the battery cell; therefore, when 20%≤S1 / S2≤90%, the connection area between the first section and the first electrode group can be further increased, the connection strength can be increased, the possibility of the adhesive being separated from the first electrode group can be further reduced, and the possibility of the filling member flowing into the electrode assembly can be reduced, and the space occupied by the first section can be smaller, so that there is more space in the outer shell for accommodating the electrolyte, which is beneficial to extending the service life of the battery cell.

[0013] In some embodiments of the present application, along the first direction, the projection area of ​​the second segment is S3, and the projection area of ​​the second portion is S4, satisfying 10%≤S3 / S4≤100%.

[0014] In the above technical solution, by making the projection area of ​​the second section along the first direction S3 and the projection area of ​​the second part S4, satisfying 10%≤S3 / S4≤100%, the connection area between the second section and the second electrode plate group can be larger, the connection strength can be greater, and the possibility of the adhesive being separated from the second electrode plate group can be reduced, thereby reducing the possibility of the filling member flowing into the interior of the electrode assembly.

[0015] In some embodiments of the present application, 20%≤S3 / S4≤90%.

[0016] In the above technical scheme, when S3 / S4 is greater than or equal to 20%, the connection area between the second section and the second electrode group can be further increased, the connection strength can be increased, the possibility of the adhesive being separated from the second electrode group can be further reduced, and the possibility of the filling member flowing into the electrode assembly can be reduced; when S3 / S4 is less than or equal to 90%, the space occupied by the second section can be smaller, so that there is more space in the outer shell for accommodating the electrolyte, which is beneficial to extending the service life of the battery cell; therefore, when 20%≤S3 / S4≤90%, the connection area between the second section and the second electrode group can be further increased, the connection strength can be increased, the possibility of the adhesive being separated from the second electrode group can be further reduced, and the possibility of the filling member flowing into the electrode assembly can be reduced, and the space occupied by the second section can be smaller, so that there is more space in the outer shell for accommodating the electrolyte, which is beneficial to extending the service life of the battery cell.

[0017] In some embodiments of the present application, the outer shell includes a first wall and a second wall arranged opposite to each other along a first direction, the first wall includes a main body wall and a step wall, along the second direction, the step wall is located at one end of the main body wall, the step wall is recessed relative to the main body wall in a direction close to the second wall, and the step wall is connected to the main body wall by a connecting wall; the second pole piece group is arranged between the step wall and the second wall, and the first pole piece group is arranged between the main body wall and the second pole piece group; the second section, the third section, the connecting wall and the main body wall form an accommodating space.

[0018] In the above technical solution, by setting the second pole piece group between the step wall and the second wall, and setting the first pole piece group between the main body wall and the second pole piece group, the contours of the outer shell and the electrode assembly can be matched, which facilitates the assembly of the outer shell and the electrode assembly, and facilitates the outer shell to protect the electrode assembly, thereby reducing the risk of damage to the electrode assembly.

[0019] In some embodiments of the present application, the second pole piece group includes a first region, and along the first direction, the first region corresponds to the accommodation space. Along the first direction, the projection area of ​​the first region is S5, and the projection area of ​​the second pole piece group is S6, satisfying 0.1%≤S5 / S6≤20%.

[0020] In the above technical scheme, when S5 / S6 is greater than or equal to 0.1%, the volume of the accommodation space corresponding to the first area is larger, which can facilitate the assembly of the electrode assembly and the outer shell, and facilitate the filler to transfer the external pressure to the first area; when S5 / S6 is less than or equal to 20%, the volume of the accommodation space corresponding to the first area can be smaller, and the internal space utilization rate of the outer shell can be higher, which is beneficial to improve the energy density of the battery cell; therefore, when 0.1%≤S5 / S6≤20%, it can facilitate the assembly of the electrode assembly and the outer shell, facilitate the filling piece to transfer the external pressure to the first area, and can also make the internal space utilization rate of the outer shell higher, which is beneficial to improve the energy density of the battery cell.

[0021] In some embodiments of the present application, the filling piece is connected to the outer shell and / or the second pole piece group.

[0022] In the above technical solution, by connecting the filling piece with the outer shell and / or the second pole piece group, the setting of the filling piece can be facilitated, and the external pressure applied to the outer shell can be easily transmitted to the area corresponding to the second pole piece group and the accommodating space, so that the pressure consistency between the area corresponding to the second pole piece group and the accommodating space and other areas of the second pole piece group is better.

[0023] In some embodiments of the present application, the outer shell is a hard shell, and along the first direction, the minimum distance between the filler and the outer shell is H, satisfying 0≤H≤5mm.

[0024] In the above technical solution, the outer shell is a hard shell, which can be deformed when subjected to force, but the deformation is small. By making the minimum distance H between the filler and the outer shell satisfy 0≤H≤5mm along the first direction, the distance between the filler and the outer shell can be made smaller, so that the outer shell can produce a smaller deformation when subjected to force and can abut against the filling piece, which is beneficial for directly transmitting the external force to the filling piece and further transmitting it to the first area.

[0025] In some embodiments of the present application, 0.4 mm ≤ H ≤ 3.5 mm.

[0026] In the above technical solution, when H is greater than or equal to 0.4 mm, it is convenient to assemble the electrode assembly and the shell, and can adapt to the processing errors of the electrode assembly and / or the shell; when H is less than or equal to 3.5 mm, it is possible to further make the distance between the filling piece and the shell smaller, so that when the shell is subjected to force, a smaller deformation occurs and the shell can abut against the filling piece, thereby facilitating the external force to be directly transmitted to the filling piece and further transmitted to the first area; therefore, when 0.4 mm≤H≤3.5 mm, it is convenient to assemble the electrode assembly and the shell, and can also facilitate the transmission of the force acting on the shell to the first area via the filling piece.

[0027] In some embodiments of the present application, the adhesive member includes a base layer and a first adhesive layer, the first adhesive layer is disposed on one side of the base layer along its thickness direction, and at least a portion of the first adhesive layer is bonded to the electrode assembly.

[0028] In the above technical solution, by making the adhesive member include a base layer and a first adhesive layer, the base layer can play a supporting role for the first adhesive layer, thereby reducing the possibility of wrinkles on the adhesive member.

[0029] In some embodiments of the present application, the adhesive member further includes a second adhesive layer, which is disposed on a side of the base layer opposite to the first adhesive layer along the thickness direction of the base layer, and a portion of the second adhesive layer is bonded to the outer shell.

[0030] In the above technical solution, by making the adhesive also include a second adhesive layer, the second adhesive layer is arranged on the side of the base layer opposite to the first adhesive layer along its thickness direction, and part of the second adhesive layer is bonded to the outer shell, so that the electrode assembly can be connected to the outer shell, reducing the possibility of damage to the electrode assembly by collision with the outer shell, which is beneficial to improving the safety and reliability of the battery cell.

[0031] In some embodiments of the present application, the base layer includes at least one of polyethylene terephthalate, polyimide, polyethylene, and polypropylene. The first adhesive layer and / or the second adhesive layer includes at least one of polyacrylic acid resin, polyethylene resin, polypropylene resin, polyethylene-propylene copolymer, epoxy resin, polyamide, styrene-butadiene rubber, butyl rubber, styrene-butadiene-styrene copolymer, styrene-isoprene-styrene copolymer, ethylene-acrylic acid copolymer, and ethylene-vinyl acetate copolymer.

[0032] In the above technical solution, by making the base layer include at least one of polyethylene terephthalate, polyimide, polyethylene, and polypropylene, the strength of the base layer can be made higher, and the support for the first adhesive layer and / or the second adhesive layer can be better. By making the first adhesive layer and / or the second adhesive layer include at least one of polyacrylic resin, polyethylene resin, polypropylene resin, polyethylene-propylene copolymer, epoxy resin, polyamide, styrene-butadiene rubber, butyl rubber, styrene-butadiene-styrene copolymer, styrene-isoprene-styrene copolymer, ethylene-acrylic acid copolymer, and ethylene-vinyl acetate copolymer, the bonding strength of the first adhesive layer and / or the second adhesive layer can be made higher, further reducing the possibility of the adhesive part being separated from the electrode assembly.

[0033] In some embodiments of the present application, the filling member includes an organic material; or, the filling member includes a composite of an organic material and an inorganic material.

[0034] In the above technical solution, since the organic material has high toughness, by making the filler include the organic material, the filler can be self-supporting and can effectively and evenly transmit pressure. Since the inorganic material has high hardness, and the composite composed of the organic material and the inorganic material can form pores, by making the filler include the organic material and the inorganic material, the filler can not only have high mechanical strength and toughness, but also have the function of absorbing and transmitting electrolyte, which is convenient for transmitting pressure to the second electrode group through the filler, and can improve the wettability of the electrolyte in the accommodating space.

[0035] In some embodiments of the present application, the organic material includes at least one of organosilicon, polyurethane, epoxy resin, polyethylene, polypropylene, ethylene-acrylic acid copolymer, ethylene-vinyl acetate copolymer, polyester, and polyamide. The inorganic material includes at least one of aluminum oxide, 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, and lithium lanthanum titanate.

[0036] In the above technical solution, by making the organic material include at least one of silicone, polyurethane, epoxy resin, polyethylene, polypropylene, ethylene-acrylic acid copolymer, ethylene-vinyl acetate copolymer, polyester, and polyamide, the filler can have good flexibility and ductility. By making the inorganic material include at least one of aluminum oxide, 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, and lithium lanthanum titanate, the filler can have high strength and hardness, good high temperature resistance, and high chemical stability, and the combination with the organic material makes the filler have high strength and toughness, good high temperature resistance, and high chemical stability.

[0037] In some embodiments of the present application, along the first direction, the projected area of ​​the first pole piece group is S2, and the projected area of ​​the second pole piece group is S6, satisfying 20%≤S2 / S6≤90%.

[0038] In the above technical scheme, when S2 / S6 is greater than or equal to 20%, the size difference between the first electrode group and the second electrode group can be smaller, which is beneficial to improving the energy density of the battery cell; when S2 / S6 is less than or equal to 90%, the size difference between the first electrode group and the second electrode group can be larger, which can allow more space at the second step to accommodate other components of the electrical equipment, which is beneficial to improving the space utilization of the battery compartment of the electrical equipment; therefore, when 20%≤S2 / S6≤90%, it can not only help to improve the energy density of the battery cell, but also allow more space at the second step to accommodate other components of the electrical equipment, which is beneficial to improving the space utilization of the battery compartment of the electrical equipment.

[0039] In a second aspect, an embodiment of the present application provides an electrical device, including a battery cell as described above, and the battery cell is used to provide electrical energy. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can also be obtained based on these drawings.

[0041] Figure 1 A schematic diagram of a three-dimensional structure of a battery cell provided in some embodiments of the present application;

[0042] Figure 2 A schematic diagram of the three-dimensional structure of an electrode assembly of a battery cell provided in some embodiments of the present application;

[0043] Figure 3 A schematic structural diagram of an electrode assembly of a battery cell provided in some embodiments of the present application from one perspective;

[0044] Figure 4 A schematic cross-sectional view of a partial structure of a battery cell provided in some embodiments of the present application;

[0045] Figure 5 A schematic cross-sectional view of a partial structure of a battery cell provided in some other embodiments of the present application;

[0046] Figure 6 Schematic diagram of the cross-sectional structure of the adhesive components of the battery cell provided in other embodiments of the present application.

[0047] Icons: 10-battery cell; 100-housing; 101-second step; 102-accommodation space; 110-first wall; 111-main body wall; 112-step wall; 113-connecting wall; 120-second wall; 130-third wall; 140-fourth wall; 150-fifth wall; 160-sixth wall; 200-electrode assembly; 201-first step; 210-first pole piece group; 210a-first positive pole piece; 210b-first negative pole piece; 210c-first diaphragm; 211-side wall; 220-first Diode group; 220a-first area; 220a1-first edge; 220a2-second edge; 220b-second area; 220c-third area; 221-first part; 222-second part; 223-first surface; 224-second surface; 300-adhesive; 301-base layer; 302-first adhesive layer; 303-second adhesive layer; 310-first section; 320-second section; 330-third section; 400-filler; X-first direction; Y-second direction; Z-third direction. DETAILED DESCRIPTION

[0048] In order to make the purpose, technical solutions and advantages of the present application clearer, the technical solutions in the embodiments of the present application will be clearly described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field belong to the scope of protection of this application.

[0049] Unless otherwise defined, all technical and scientific terms used in this application have the same meanings as those commonly understood by technicians in the technical field to which this application belongs; the terms used in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" in the specification and claims of this application and the above-mentioned figure descriptions and any variations thereof are intended to cover non-exclusive inclusions.

[0050] The terms "first", "second", etc. in the specification and claims of this application or the above-mentioned drawings are used to distinguish different objects, rather than to describe a specific order or a primary and secondary relationship.

[0051] Reference to "embodiment" in this application means that a particular feature, structure, or characteristic described in conjunction with the embodiment may be included in at least one embodiment of the present application. The appearance of the phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments.

[0052] In the embodiments of the present application, the same reference numerals represent 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 the present application shown in the drawings, as well as the overall thickness, length, width and other dimensions of the integrated device are only exemplary descriptions and should not constitute any limitation to the present application.

[0053] With the development of the new energy industry, batteries are gradually developing in the direction of high energy density and high power density, and the safety requirements for batteries are also getting higher and higher. In order to adapt to the shapes of different battery compartments in electrical equipment, the shape of the battery cell also changes accordingly. For example, a battery cell with a step is provided, and the components of the electrical equipment can be accommodated in the step of the battery cell, thereby improving the utilization rate of the battery compartment. In this type of battery cell, a plurality of electrode groups of different sizes are provided in the shell, so that a step is formed at the junction of adjacent electrode groups. For example, the electrode assembly includes a first electrode group and a second electrode group, the size of the first electrode group is smaller than the size of the second electrode group, and a step is formed on one side of the first electrode group. In some processes of preparing the battery cell, pressure needs to be applied to the electrode assembly or to the electrode assembly through the shell, but due to process limitations, the step cannot be directly subjected to force, which will make the first area of ​​the second electrode group corresponding to the step and other areas unevenly subjected to force, resulting in the weakening of the bonding force between the negative electrode sheet and the diaphragm in the first area. During the charge and discharge cycle of the battery cell, the negative electrode sheet in the first area may produce the problem of metal ion precipitation, affecting the safety and reliability of the battery cell.

[0054] In order to improve the safety and reliability of a battery cell, the present application provides a battery cell, the battery cell comprises a shell, an electrode assembly, an adhesive and a filling member, the electrode assembly is accommodated in the shell, and the electrode assembly is a laminated structure; the electrode assembly comprises a first electrode group and a second electrode group, the first electrode group and the second electrode group are stacked along a first direction, the size of the first electrode group along a second direction is smaller than the size of the second electrode group along the second direction; along the first direction, the second electrode group has a first surface facing the first electrode group, the second electrode group comprises a first part overlapping with the projection of the first electrode group, and a second part not overlapping with the first electrode group, the side wall of the first electrode group close to the second part in the second direction forms a first step with the first surface of the second part; the shell forms a second step corresponding to the first step. The adhesive member is adhered to the first step, and along the second direction, a receiving space is formed between the adhesive member and the second step. The filling member is arranged in the receiving space. The first direction is parallel to the thickness direction of the electrode assembly, and the first direction is perpendicular to the second direction.

[0055] In the battery cell of this structure, by accommodating the electrode assembly in the shell, the electrode assembly is a laminated structure, which can make the electrode assembly occupy a larger space in the shell, which is conducive to improving the energy density of the battery cell. By making the side wall of the first electrode plate group close to the second part in the second direction and the first surface of the second part form a first step, and the shell forms a second step corresponding to the first step, when the battery cell is installed in the battery compartment of the electrical equipment, other components in the battery compartment can be placed at the second step, thereby improving the space utilization of the battery compartment, and further improving the compactness of the internal structure of the electrical equipment. By making the filler be arranged in the accommodating space, the filler fills the accommodating space or the filler cooperates with the electrolyte in the accommodating space, the external pressure on the shell is transmitted to the area corresponding to the second electrode plate group and the accommodating space, so that the pressure consistency of this area and other areas of the second electrode plate group is better, which can reduce the risk of metal ion precipitation in the battery cell during the cycle process and improve the safety and reliability of the battery cell. By making the adhesive adhere to the first step, a receiving space is formed between the adhesive and the second step along the second direction, and the filler is arranged in the receiving space, so that when the filler is filled in the receiving space in a fluid state, the adhesive can block the filler from flowing into the interior of the electrode assembly, thereby preventing the filler from interfering with the internal chemical system of the battery cell, thereby reducing the possibility of the filler affecting the volume of the electrode assembly and the spacing distance between the pole pieces, and can also play a buffering role when subjected to external force, thereby reducing the possibility of the electrode assembly being directly damaged by the force.

[0056] The battery cell provided in the embodiment of the present application may be a secondary battery or a primary battery, for example, a lithium ion battery, a sodium ion battery or a magnesium ion battery, etc., but the embodiment of the present application is not limited to this.

[0057] The embodiments of the present application provide an electrical device that uses a battery cell as a power source. The electrical device may be, but is not limited to, a mobile phone, a tablet, a laptop computer, an electric toy, an electric tool, an electric vehicle, an electric car, a ship, a spacecraft, and the like.

[0058] See also Figures 1 to 4 , Figure 1 A schematic diagram of a three-dimensional structure of a battery cell provided in some embodiments of the present application; Figure 2 A schematic diagram of the three-dimensional structure of an electrode assembly of a battery cell provided in some embodiments of the present application; Figure 3 A schematic structural diagram of an electrode assembly of a battery cell provided in some embodiments of the present application from one perspective; Figure 4 A schematic cross-sectional view of a partial structure of a battery cell provided in some embodiments of the present application.

[0059] The embodiment of the present application provides a battery cell 10 , which includes a housing 100 and an electrode assembly 200 . The electrode assembly 200 is accommodated in the housing 100 , and the electrode assembly 200 is a laminated structure.

[0060] By accommodating the electrode assembly 200 in the housing 100 , the electrode assembly 200 has a laminated structure, which can allow the electrode assembly 200 to occupy a larger space in the housing 100 , thereby facilitating improving the energy density of the battery cell 10 .

[0061] In some embodiments, the shell 100 can be made of a material with higher strength, such as metal materials such as steel and aluminum alloy, so that the shell 100 has a higher force-bearing performance, thereby making the shell 100 less likely to be deformed or damaged due to force or environmental changes, thereby making the battery cell 10 more reliable.

[0062] In other embodiments, the housing 100 may also be made of non-metallic materials with relatively high strength, such as carbon fiber, hard plastic, etc.

[0063] The battery cell 10 also includes an electrolyte, which is contained in the housing 100. The electrode assembly 200 is composed of a positive electrode sheet, a negative electrode sheet and a separator. The battery cell 10 mainly relies on the movement of metal ions between the positive electrode sheet and the negative electrode sheet to work. The positive electrode sheet includes a positive electrode collector and a positive electrode active material layer, the positive electrode active material layer is coated on the surface of the positive electrode collector, and the part of the positive electrode collector that is not coated with the positive electrode active material layer is used as a positive electrode ear to realize the input or output of the electric energy of the positive electrode sheet through the positive electrode ear. Taking a lithium-ion battery as an example, the material of the positive electrode collector can be aluminum, and the positive electrode active material can be lithium cobalt oxide, lithium iron phosphate, ternary material or lithium manganese oxide. The negative electrode sheet includes a negative electrode collector and a negative electrode active material layer, the negative electrode active material layer is coated on the surface of the negative electrode collector, and the part of the negative electrode collector that is not coated with the negative electrode active material layer is used as a negative electrode ear to realize the input or output of the electric energy of the negative electrode sheet through the negative electrode ear. The negative electrode current collector may be made of copper, and the negative electrode active material may be made of carbon material or silicon material, etc. The material of the separator may be made of polypropylene (PP) or polyethylene (PE), etc. The electrolyte may include an organic solvent, an electrolyte lithium salt, etc.

[0064] In some embodiments, the electrode assembly 200 includes a first electrode sheet group 210 and a second electrode sheet group 220 , and the first electrode sheet group 210 and the second electrode sheet group 220 are stacked along a first direction X.

[0065] In some embodiments, the first electrode sheet group 210 includes a first positive electrode sheet 210a, a first negative electrode sheet 210b and a first separator 210c, and the first positive electrode sheet 210a, the first separator 210c and the first negative electrode sheet 210b are stacked along the first direction X. The second electrode sheet group 220 includes a second positive electrode sheet, a second negative electrode sheet and a second separator, and the second positive electrode sheet, the second separator and the second negative electrode sheet are stacked along the first direction X.

[0066] In some embodiments, the size of the first pole piece group 210 along the second direction Y is smaller than the size of the second pole piece group 220 along the second direction Y. Along the first direction X, the second pole piece group 220 has a first surface 223 facing the first pole piece group 210, the second pole piece group 220 includes a first portion 221 overlapping with the projection of the first pole piece group 210, and a second portion 222 not overlapping with the first pole piece group 210, and a side wall 211 of the first pole piece group 210 close to the second portion 222 in the second direction Y and a first surface 223 of the second portion 222 form a first step 201. The housing 100 is formed with a second step 101 corresponding to the first step 201.

[0067] By forming a first step 201 between the side wall 211 of the first electrode group 210 close to the second part 222 in the second direction Y and the first surface 223 of the second part 222, and the outer shell 100 forms a second step 101 corresponding to the first step 201, when the battery cell 10 is installed in the battery compartment of an electrical device, other components in the battery compartment can be placed at the second step 101, thereby improving the space utilization of the battery compartment and further improving the compactness of the internal structure of the electrical device.

[0068] In some embodiments, the battery cell 10 further includes an adhesive 300 and a filler 400 . The adhesive 300 is adhered to the first step 201 . Along the second direction Y, a receiving space 102 is formed between the adhesive 300 and the second step 101 . The filler 400 is disposed in the receiving space 102 .

[0069] The first direction X is parallel to the thickness direction of the electrode assembly 200 , and the first direction X is perpendicular to the second direction Y.

[0070] By setting the filling piece 400 in the accommodating space 102, the filling piece 400 fills the accommodating space 102 or the filling piece 400 cooperates with the electrolyte in the accommodating space 102, the external pressure applied to the outer shell 100 is transmitted to the area of ​​the second electrode group 220 corresponding to the accommodating space 102, so that the pressure applied to this area and other areas of the second electrode group 220 are more consistent, which can reduce the risk of metal ion precipitation in the battery cell 10 during the cycle process, and improve the safety and reliability of the battery cell 10. By making the adhesive 300 adhere to the first step 201, a receiving space 102 is formed between the adhesive 300 and the second step 101 along the second direction Y, and the filler 400 is arranged in the receiving space 102, so that when the filler 400 is filled in the receiving space 102 in a fluid state, the adhesive 300 can block the filler 400 from flowing into the electrode assembly 200, preventing the filler 400 from interfering with the internal chemical system of the battery cell 10, thereby reducing the possibility of the filler 400 affecting the volume of the electrode assembly 200 and the spacing distance between the pole pieces, and can also play a buffering role when subjected to external force, reducing the possibility of the electrode assembly 200 being directly subjected to force and being damaged.

[0071] In some embodiments, the adhesive 300 includes a first section 310, a second section 320 and a third section 330, the first section 310 is adhered to the side of the first pole piece group 210 away from the second pole piece group 220 along the first direction X, the second section 320 is adhered to the second part 222, and the third section 330 connects the first section 310 and the second section 320.

[0072] By making the first section 310 adhere to the side of the first electrode sheet group 210 away from the second electrode sheet group 220 along the first direction X, and the second section 320 adhere to the second portion 222, the adhesion area of ​​the adhesive 300 and the electrode assembly 200 can be larger, the connection strength between the adhesive 300 and the electrode assembly 200 is higher, and the possibility of the adhesive 300 being separated from the electrode assembly 200 is reduced. By making the second section 320 adhere to the second portion 222, the third section 330 connects the first section 310 and the second section 320, so that the projection of the third section 330 in the second direction Y can cover the end face of the first electrode sheet group 210 along the second direction Y, thereby further reducing the possibility of the filler 400 flowing from the end face of the first electrode sheet group 210 into the first electrode sheet group 210 or between the first electrode sheet group 210 and the second electrode sheet group 220.

[0073] In some embodiments, along the first direction X, the projection area of ​​the first segment 310 is S1, and the projection area of ​​the first pole piece group 210 is S2, satisfying 10%≤S1 / S2≤100%. For example, S1 / S2 can be 10%, 30%, 50%, 70%, 90% or 100%.

[0074] By ensuring that the projection area S1 of the first section 310 and the projection area S2 of the first electrode plate group 210 along the first direction X satisfy 10%≤S1 / S2≤100%, the connection area between the first section 310 and the first electrode plate group 210 can be larger and the connection strength can be greater, thereby reducing the possibility of the adhesive 300 detaching from the first electrode plate group 210, and further reducing the possibility of the filler 400 flowing into the interior of the electrode assembly 200.

[0075] In some embodiments, 20%≤S1 / S2≤90%. For example, S1 / S2 may be 20%, 40%, 60%, 80% or 90%.

[0076] When S1 / S2 is greater than or equal to 20%, the connection area between the first section 310 and the first electrode plate group 210 can be further increased, the connection strength can be increased, the possibility of the adhesive 300 being separated from the first electrode plate group 210 can be further reduced, and the possibility of the filling member 400 flowing into the electrode assembly 200 can be reduced; when S1 / S2 is less than or equal to 90%, the space occupied by the first section 310 can be smaller, so that there can be more space in the outer shell 100 for accommodating electrolyte, which is beneficial to extending the service life of the battery cell 10; therefore, when 20%≤S1 / S2≤90%, the connection area between the first section 310 and the first electrode plate group 210 can be further increased, the connection strength can be increased, the possibility of the adhesive 300 being separated from the first electrode plate group 210 can be further reduced, and the possibility of the filling member 400 flowing into the electrode assembly 200 can be reduced, and the space occupied by the first section 310 can be smaller, so that there can be more space in the outer shell 100 for accommodating electrolyte, which is beneficial to extending the service life of the battery cell 10.

[0077] In some embodiments, along the first direction X, the projection area of ​​the second segment 320 is S3, and the projection area of ​​the second portion 222 is S4, satisfying 10%≤S3 / S4≤100%. For example, S3 / S4 can be 10%, 30%, 50%, 70%, 90% or 100%.

[0078] By making the projection area of ​​the second section 320 along the first direction X be S3, and the projection area of ​​the second part 222 be S4, satisfying 10%≤S3 / S4≤100%, the connection area between the second section 320 and the second pole piece group 220 can be larger, the connection strength can be greater, and the possibility of the adhesive 300 detaching from the second pole piece group 220 can be reduced, thereby reducing the possibility of the filler 400 flowing into the interior of the electrode assembly 200.

[0079] In some embodiments, 20%≤S3 / S4≤90%. For example, S3 / S4 may be 20%, 40%, 60%, 80% or 90%.

[0080] When S3 / S4 is greater than or equal to 20%, the connection area between the second section 320 and the second electrode plate group 220 can be further increased, the connection strength can be increased, the possibility of the adhesive 300 being separated from the second electrode plate group 220 can be further reduced, and the possibility of the filling member 400 flowing into the electrode assembly 200 can be reduced; when S3 / S4 is less than or equal to 90%, the space occupied by the second section 320 can be smaller, so that there is more space in the outer shell 100 for accommodating electrolyte, which is beneficial to extending the service life of the battery cell 10; therefore, when 20%≤S3 / S4≤90%, the connection area between the second section 320 and the second electrode plate group 220 can be further increased, the connection strength can be increased, the possibility of the adhesive 300 being separated from the second electrode plate group 220 can be further reduced, and the possibility of the filling member 400 flowing into the electrode assembly 200 can be reduced, and the space occupied by the second section 320 can be smaller, so that there is more space in the outer shell 100 for accommodating electrolyte, which is beneficial to extending the service life of the battery cell 10.

[0081] See also Figure 1 In some embodiments, the housing 100 includes a first wall 110 and a second wall 120 that are arranged opposite to each other along a first direction X. The first wall 110 includes a main body wall 111 and a step wall 112. Along the second direction Y, the step wall 112 is located at one end of the main body wall 111. The step wall 112 is recessed relative to the main body wall 111 toward the direction close to the second wall 120. The step wall 112 is connected to the main body wall 111 through a connecting wall 113. The step wall 112, the main body wall 111, and the connecting wall 113 form a second step 101.

[0082] The second pole piece group 220 is disposed between the step wall 112 and the second wall 120, and the first pole piece group 210 is disposed between the main body wall 111 and the second pole piece group 220. The second section 320, the third section 330, the connecting wall 113 and the main body wall 111 form an accommodation space 102.

[0083] By arranging the second pole piece group 220 between the step wall 112 and the second wall 120 and the first pole piece group 210 between the main wall 111 and the second pole piece group 220, the contours of the outer shell 100 and the electrode assembly 200 can be matched, which facilitates the assembly of the outer shell 100 and the electrode assembly 200, and facilitates the outer shell 100 to protect the electrode assembly 200, thereby reducing the risk of damage to the electrode assembly 200.

[0084] In some embodiments, the first wall 110 may be integrally formed. For example, the main body wall 111, the step wall 112 and the connecting wall 113 may be formed by stamping, integral injection molding, etc. This can facilitate the preparation of the first wall 110 and increase the overall strength of the first wall 110.

[0085] In some embodiments, the housing 100 may further include a third wall 130 and a fourth wall 140 disposed oppositely along the second direction Y, and a fifth wall 150 and a sixth wall 160 disposed oppositely along the third direction Z. The third wall 130 connects the main body wall 111 and the second wall 120, the fourth wall 140 connects the step wall 112 and the second wall 120, one end of the fifth wall 150 connects the main body wall 111, the step wall 112 and the connecting wall 113, and the other end connects the second wall 120, and one end of the sixth wall 160 connects the main body wall 111, the step wall 112 and the connecting wall 113, and the other end connects the second wall 120. The first direction X, the second direction Y, and the third direction Z are perpendicular to each other.

[0086] See also Figure 4 In some embodiments, the second pole piece group 220 includes a first region 220a, and along the first direction X, the first region 220a corresponds to the accommodation space 102. Along the first direction X, the projection area of ​​the first region 220a is S5, and the projection area of ​​the second pole piece group 220 is S6, satisfying 0.1%≤S5 / S6≤20%. For example, S5 / S6 can be 0.1%, 0.5%, 1%, 3%, 5%, 10%, 15% or 20%, etc.

[0087] Herein, along the first direction X, the first area 220a corresponds to the accommodating space 102 , which means that at least a portion of the projection of the first area 220a along the first direction X is located in the accommodating space 102 , or the projection of the first area 220a along the first direction X covers the accommodating space 102 .

[0088] The second pole piece set 220 has a second surface 224 opposite to the first surface 223 along the first direction X. The first region 220 a extends from the first surface 223 of the second pole piece set 220 to the second surface 224 .

[0089] When S5 / S6 is greater than or equal to 0.1%, the volume of the accommodating space 102 corresponding to the first region 220a is larger, which can facilitate the assembly of the electrode assembly 200 and the outer shell 100, and facilitate the filling piece 400 to transfer the external pressure to the first region 220a; when S5 / S6 is less than or equal to 20%, the volume of the accommodating space 102 corresponding to the first region 220a can be smaller, which can make the internal space utilization rate of the outer shell 100 higher, which is beneficial to improve the energy density of the battery cell 10; therefore, when 0.1%≤S5 / S6≤20%, it can facilitate the assembly of the electrode assembly 200 and the outer shell 100, facilitate the filling piece 400 to transfer the external pressure to the first region 220a, and make the internal space utilization rate of the outer shell 100 higher, which is beneficial to improve the energy density of the battery cell 10.

[0090] In some embodiments, 1%≤S5 / S6≤15%. For example, S5 / S6 may be 1%, 2%, 7%, 9%, 11%, 13% or 15%.

[0091] When S5 / S6 is greater than or equal to 1%, the volume of the accommodating space 102 corresponding to the first region 220a is further increased, which can further facilitate the assembly of the electrode assembly 200 and the outer shell 100, and further facilitate the filling piece 400 to transfer the external pressure to the first region 220a; when S5 / S6 is less than or equal to 15%, the volume of the accommodating space 102 corresponding to the first region 220a is further decreased, and the internal space utilization rate of the outer shell 100 is further increased, which is beneficial to further improve the energy density of the battery cell 10; therefore, when 1%≤S5 / S6≤15%, it can not only further facilitate the assembly of the electrode assembly 200 and the outer shell 100, and further facilitate the filling piece 400 to transfer the external pressure to the first region 220a, but also further make the internal space utilization rate of the outer shell 100 higher, which is beneficial to further improve the energy density of the battery cell 10.

[0092] In some embodiments, the edge of the first region 220a may extend beyond the accommodation space 102 along the second direction Y. For example, along the first direction X, the first region 220a has a first overlapping region overlapping the first pole piece group 210 , and the first region 220a has a second overlapping region overlapping the step wall 112 .

[0093] In some embodiments, the first electrode group 210 includes a first positive electrode 210a, a first negative electrode 210b, and a first separator 210c. Along the second direction Y, the first region 220a has a first edge 220a1 and a second edge 220a2, the first edge 220a1 is close to the first electrode group 210 in the second direction Y, and the second edge 220a2 is away from the first electrode group 210 in the second direction Y. Along the second direction Y, the first edge 220a1 extends to the region of the second electrode group 220 corresponding to the first positive electrode 210a, and the second edge 220a2 extends to the region of the second electrode group 220 corresponding to the step wall 112.

[0094] In some embodiments, the second pole piece group 220 further includes a second region 220b and a third region 220c, the second region 220b, the first region 220a and the third region 220c are arranged along the second direction Y, and the first region 220a connects the second region 220b and the third region 220c. Along the first direction X, the projection of the second region 220b overlaps with a portion of the main body wall 111, and the third region 220c overlaps with at least a portion of the step wall 112.

[0095] In some embodiments, the filler 400 is connected to the housing 100 and / or the second pole piece assembly 220 .

[0096] By connecting the filling piece 400 to the outer shell 100 and / or the second pole piece group 220, the setting of the filling piece 400 can be facilitated, and the external pressure applied to the outer shell 100 can be easily transmitted to the area of ​​the second pole piece group 220 corresponding to the accommodating space 102, so that the pressure consistency between the area corresponding to the second pole piece group 220 and the accommodating space 102 and other areas of the second pole piece group 220 is better.

[0097] When the filling piece 400 is connected to the outer shell 100, the external pressure applied to the outer shell 100 can be directly transmitted to the filling piece 400, and then transmitted to the second electrode assembly 220 through the filling piece 400 or through the filling piece 400 and the electrode liquid, thereby further making the pressure consistency between the area of ​​the second electrode assembly 220 corresponding to the accommodating space 102 and other areas of the second electrode assembly 220 better.

[0098] When the filling piece 400 is connected to the second pole piece group 220, the external pressure on the outer shell 100 is transmitted to the filling piece 400, and can be directly transmitted to the second pole piece group 220 through the filling piece 400, further making the pressure consistency between the area corresponding to the second pole piece group 220 and the accommodating space 102 and other areas of the second pole piece group 220 better.

[0099] When the filling piece 400 is connected to the outer shell 100 and the second pole piece group 220, the external pressure received by the outer shell 100 can be directly transmitted to the second pole piece group 220 through the filling piece 400, further making the pressure consistency between the area corresponding to the second pole piece group 220 and the accommodating space 102 and other areas of the second pole piece group 220 better.

[0100] See also Figure 4 In some embodiments, the filling piece 400 may fill the accommodation space 102 , so that the filling piece 400 is connected to the housing 100 and the second pole piece assembly 200 .

[0101] See also Figure 5 , Figure 5 Schematic cross-sectional view of a partial structure of a battery cell provided in some other embodiments of the present application.

[0102] In other embodiments, the filler 400 may fill part of the accommodating space 102 , which can reduce the possibility of the filler 400 squeezing the adhesive 300 and causing damage to the adhesive 300 , and reduce the possibility of the filler 400 penetrating into the interior of the electrode assembly 200 .

[0103] In some embodiments, the housing 100 is a hard shell, such as a steel shell, an aluminum shell, etc., and the minimum distance between the filler 400 and the housing 100 along the first direction X is H, satisfying 0≤H≤5mm. For example, H can be 0, 0.1mm, 1mm, 3mm or 5mm, etc.

[0104] The outer shell 100 is a hard shell, and can be deformed when subjected to force, but the deformation is small. By making the minimum distance H between the filler 400 and the outer shell 100 along the first direction X satisfy 0≤H≤5mm, the distance between the filler 400 and the outer shell 100 can be made smaller, so that the outer shell 100 can produce a smaller deformation when subjected to force and can abut against the filler 400, thereby facilitating the direct transmission of external force to the filler 400 and further to the first area 220a.

[0105] In some embodiments, 0.4 mm ≤ H ≤ 3.5 mm. For example, H may be 0.4 mm, 0.7 mm, 1.2 mm, 2.5 mm, or 3.5 mm.

[0106] When H is greater than or equal to 0.4 mm, it is convenient to assemble the electrode assembly 200 and the shell 100, and can adapt to the processing errors of the electrode assembly 200 and / or the shell 100; when H is less than or equal to 3.5 mm, it is possible to further make the distance between the filling piece 400 and the shell 100 smaller, so that when the shell 100 is subjected to force, it can produce a smaller deformation and abut against the filling piece 400, thereby facilitating the external force to be directly transmitted to the filling piece 400 and further transmitted to the first area 220a; therefore, when 0.4 mm≤H≤3.5 mm, it is convenient to assemble the electrode assembly 200 and the shell 100, and can also facilitate the transmission of the force acting on the shell 100 to the first area 220a via the filling piece 400.

[0107] See also Figure 6 , Figure 6 Schematic diagram of the cross-sectional structure of the adhesive components of the battery cell provided in other embodiments of the present application.

[0108] In some embodiments, the adhesive member 300 includes a base layer 301 and a first adhesive layer 302 , the first adhesive layer 302 is disposed on one side of the base layer 301 along the thickness direction thereof, and at least a portion of the first adhesive layer 302 is bonded to the electrode assembly 200 .

[0109] By making the adhesive member 300 include the base layer 301 and the first adhesive layer 302 , the base layer 301 can support the first adhesive layer 302 , thereby reducing the possibility of wrinkles on the adhesive member 300 .

[0110] In some embodiments, the adhesive member 300 further includes a second adhesive layer 303 , which is disposed on a side of the base layer 301 opposite to the first adhesive layer 302 along the thickness direction thereof, and a portion of the second adhesive layer 303 is bonded to the housing 100 .

[0111] By making the adhesive 300 also include a second adhesive layer 303, the second adhesive layer 303 is arranged on the side of the base layer 301 opposite to the first adhesive layer 302 along its thickness direction, and a portion of the second adhesive layer 303 is bonded to the outer shell 100, the electrode assembly 200 can be connected to the outer shell 100, reducing the possibility of damage to the electrode assembly 200 due to collision with the outer shell 100, which is beneficial to improving the safety and reliability of the battery cell 10.

[0112] In some embodiments, the base layer 301 includes at least one of polyethylene terephthalate, polyimide, polyethylene, and polypropylene.

[0113] By making the base layer 301 include at least one of polyethylene terephthalate, polyimide, polyethylene, and polypropylene, the base layer 301 can be made stronger and provide better support for the first adhesive layer 302 and / or the second adhesive layer 303 .

[0114] In some embodiments, the first adhesive layer 302 and / or the second adhesive layer 303 include at least one of polyacrylic resin, polyethylene resin, polypropylene resin, polyethylene-propylene copolymer, epoxy resin, polyamide, styrene-butadiene rubber, butyl rubber, styrene-butadiene-styrene copolymer, styrene-isoprene-styrene copolymer, ethylene-acrylic acid copolymer, and ethylene-vinyl acetate copolymer.

[0115] By making the first adhesive layer 302 and / or the second adhesive layer 303 include at least one of polyacrylic resin, polyethylene resin, polypropylene resin, polyethylene-propylene copolymer, epoxy resin, polyamide, styrene-butadiene rubber, butyl rubber, styrene-butadiene-styrene copolymer, styrene-isoprene-styrene copolymer, ethylene-acrylic acid copolymer, and ethylene-vinyl acetate copolymer, the bonding strength of the first adhesive layer 302 and / or the second adhesive layer 303 can be increased, further reducing the possibility of the adhesive 300 detaching from the electrode assembly 200.

[0116] In some embodiments, filler 400 includes an organic material.

[0117] Since organic materials have high toughness, by making the filler 400 include organic materials, the filler 400 can be self-supporting and can effectively and evenly transmit pressure.

[0118] In some embodiments, the filler 400 includes a composite of an organic material and an inorganic material.

[0119] Since inorganic materials have high hardness and the composite composed of organic materials and inorganic materials can form pores, by making the filler 400 a composite composed of organic materials and inorganic materials, the filler 400 can not only have high mechanical strength and toughness, but also have the function of absorbing and transmitting electrolyte, which makes it easy to transfer pressure to the second electrode group 220 through the filler 400 and can improve the wettability of the electrolyte in the accommodating space 102.

[0120] In some embodiments, the organic material includes at least one of silicone, polyurethane, epoxy resin, polyethylene, polypropylene, ethylene-acrylic acid copolymer, ethylene-vinyl acetate copolymer, polyester, and polyamide.

[0121] By making the organic material include at least one of silicone, polyurethane, epoxy resin, polyethylene, polypropylene, ethylene-acrylic acid copolymer, ethylene-vinyl acetate copolymer, polyester, and polyamide, the filling member 400 can have good flexibility and ductility.

[0122] In some embodiments, the inorganic material includes at least one of aluminum oxide, 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, and lithium lanthanum titanate.

[0123] By making the inorganic material include at least one of aluminum oxide, 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, and lithium lanthanum titanate, the filler 400 can have higher strength and hardness, better high temperature resistance, and higher chemical stability. When combined with organic materials, the filler 400 has higher strength and toughness, better high temperature resistance, and higher chemical stability.

[0124] See also Figures 1 to 3 In some embodiments, along the first direction X, the projection area of ​​the first pole piece group 210 is S2, and the projection area of ​​the second pole piece group 220 is S6, satisfying 20%≤S2 / S6≤90%. For example, S2 / S6 can be 20%, 40%, 60%, 80% or 90%.

[0125] When S2 / S6 is greater than or equal to 20%, the size difference between the first electrode group 210 and the second electrode group 220 can be smaller, which is beneficial to improving the energy density of the battery cell 10; when S2 / S6 is less than or equal to 90%, the size difference between the first electrode group 210 and the second electrode group 220 can be larger, which can allow the second step 101 to have more space for accommodating other components of the electrical equipment, which is beneficial to improving the space utilization rate of the battery compartment of the electrical equipment; therefore, when 20%≤S2 / S6≤90%, it can not only help to improve the energy density of the battery cell 10, but also allow the second step 101 to have more space for accommodating other components of the electrical equipment, which is beneficial to improving the space utilization rate of the battery compartment of the electrical equipment.

[0126] In some embodiments, 30%≤S2 / S6≤80%. For example, S2 / S6 may be 30%, 50%, 70%, or 80%.

[0127] When S2 / S6 is greater than or equal to 30%, the size difference between the first electrode group 210 and the second electrode group 220 can be further reduced, which is beneficial to further improve the energy density of the battery cell 10; when S2 / S6 is less than or equal to 80%, the size difference between the first electrode group 210 and the second electrode group 220 can be further increased, which can further allow the second step 101 to have more space for accommodating other components of the electrical equipment, which is beneficial to further improve the space utilization rate of the battery compartment of the electrical equipment; therefore, when 30%≤S2 / S6≤80%, it can not only further improve the energy density of the battery cell 10, but also allow the second step 101 to have more space for accommodating other components of the electrical equipment, which is beneficial to further improve the space utilization rate of the battery compartment of the electrical equipment.

[0128] An embodiment of the present application provides an electrical device, including the battery cell 10 provided in any of the above embodiments, and the battery cell 10 is used to provide electrical energy.

[0129] The electrical device may be any of the aforementioned devices or systems using the battery cell 10 .

[0130] The features and performance of the battery cell of the present application are further described in detail below in conjunction with the embodiments.

[0131] The battery cells in each embodiment and comparative example were prepared and tested according to the following directions.

[0132] Preparation method of battery cell:

[0133] 1. Preparation of positive electrode sheet

[0134] The active material lithium cobalt oxide, the conductive agent (conductive carbon (super P)), and the binder (polyvinylidene fluoride (PVDF)) are fully stirred and mixed in an N-methylpyrrolidone solvent system at a weight ratio of 94:3:3, and then coated on an aluminum foil, dried, and cold pressed to obtain a positive electrode sheet.

[0135] 2. Preparation of negative electrode sheet

[0136] Active material artificial graphite, conductive agent (conductive carbon (super P)), adhesive (styrene-butadiene rubber (SBR)), thickener (sodium carbon methyl cellulose (CMC)) are fully stirred and mixed in a deionized water solvent system at a weight ratio of 97:1:1.5:0.5, and then coated on copper foil, dried, and cold pressed to obtain a negative electrode sheet.

[0137] 3. Preparation of electrode assembly

[0138] The positive electrode sheet, the separator, and the negative electrode sheet are stacked in order, with the separator being located between the positive electrode sheet and the negative electrode sheet to play an isolating role, to obtain a first electrode sheet group and a second electrode sheet group, and the first electrode sheet group and the second electrode sheet group are hot-pressed and composited to form an electrode assembly having a first step.

[0139] 4. Setting of adhesive parts

[0140] An adhesive is adhered to the first step of the electrode assembly so that the first section of the adhesive is adhered to the side of the first electrode group facing away from the second electrode group, the second section is adhered to the second part of the second electrode group that does not overlap with the first electrode group, and the third section connects the first section and the second section.

[0141] 5. Setting of filling parts

[0142] The electrode assembly is placed in the shell, and a filling member is arranged in the accommodation space between the shell and the adhesive member.

[0143] 6. Battery cell assembly

[0144] The electrolyte is injected into the shell and sealed, and then formed into a finished battery cell after forming and hot pressing. The forming temperature is 75° C., the pressure is 1.0 MPa, and the forming and hot pressing time is 60 minutes.

[0145] In the preparation method of the battery cell of Comparative Example 1, the above step 4 and step 5 are omitted, in the preparation method of the battery cell of Comparative Example 2, the above step 4 is omitted, and in the preparation method of the battery cell of Comparative Example 3, the above step 5 is omitted.

[0146] Adhesive coverage test on electrode assembly:

[0147] 1. Disassemble the finished battery cell after discharging, clean the residual electrolyte on the surface of the battery cell with anhydrous ethanol, and then bake it in an oven at 60°C for 24 hours.

[0148] 2. Use a CCD image tester to directly measure the coverage area S1 of the adhesive on the first electrode group, the area S2 of the first electrode group, the coverage area S3 of the adhesive on the second part of the second electrode group that does not overlap with the first electrode group, and the area S4 of the second part of the second electrode group that does not overlap with the first electrode group.

[0149] 3. Calculate the coverage S1 / S2*100% of the adhesive on the first pole piece group and the coverage S3 / S4*100% of the second portion of the adhesive that does not overlap the first pole piece group.

[0150] Cell interface test method:

[0151] Take the finished battery cell after it is fully charged at 0.5C, disassemble it, observe whether there are black spots on the interface of the negative electrode due to lithium plating, and take photos with a camera to record them.

[0152] Battery drop test method:

[0153] 1. Fully charge the finished battery cell, then put it into the fixture and drop it from a height of 1.5m. Each of the six sides of the battery cell should drop 6 times. Each group of 10 batteries should be tested, and each group should be tested 3 times.

[0154] 2. Test the change in the open circuit voltage of the battery cell before and after the drop and whether the battery cell catches fire. The battery cell with voltage drop and fire will be marked as failed.

[0155] Preparation of Comparative Examples and Examples:

[0156] Comparative Example 1

[0157] According to the above method, the first pole piece group and the second pole piece group are manufactured, and after hot pressing and compounding, liquid injection and chemical formation are performed without setting adhesive members and filling members to obtain a finished battery cell.

[0158] Comparative Example 2

[0159] The first electrode assembly and the second electrode assembly are prepared according to the above method. After hot pressing and compounding, a silicone filler is arranged in the accommodation space formed between the first step of the electrode assembly and the second step of the shell, and no adhesive is arranged. Then, liquid injection and chemical formation are carried out to obtain a finished battery cell.

[0160] Comparative Example 3

[0161] The first pole piece group and the second pole piece group are prepared according to the above method. After hot pressing and compounding, a single-sided adhesive (the base layer is polyethylene terephthalate (PET) and the adhesive layer is polypropylene resin (PP)) is adhered to the first step of the electrode assembly, so that the coverage area ratio of the adhesive on the first pole piece group is 50%, and the coverage area ratio on the second part of the second pole piece group that does not overlap with the first pole piece is 50%. No filling member is set, and then liquid injection and chemical formation are carried out to obtain a finished battery cell.

[0162] Example 1

[0163] A first pole piece group and a second pole piece group are prepared according to the above method. After hot pressing and compounding, a single-sided adhesive (the base layer is polyethylene terephthalate (PET) and the adhesive layer is polypropylene resin (PP)) is adhered to the first step of the electrode assembly, so that the coverage area ratio of the adhesive on the first pole piece group is 5%, and the coverage area ratio on the second part of the second pole piece group that does not overlap with the first pole piece is 50%. A silicone filler is arranged in the accommodating space formed between the adhesive and the shell, and then liquid injection and chemical formation are carried out to obtain a finished battery cell.

[0164] Example 2

[0165] A first pole piece group and a second pole piece group are prepared according to the above method. After hot pressing and compounding, a single-sided adhesive (the base layer is polyethylene terephthalate (PET) and the adhesive layer is polypropylene resin (PP)) is adhered to the first step of the electrode assembly, so that the coverage area ratio of the adhesive on the first pole piece group is 10%, and the coverage area ratio on the second part of the second pole piece group that does not overlap with the first pole piece is 50%. A silicone filler is arranged in the accommodating space formed between the adhesive and the shell, and then liquid injection and chemical formation are carried out to obtain a finished battery cell.

[0166] Example 3

[0167] A first pole piece group and a second pole piece group are prepared according to the above method. After hot pressing and compounding, a single-sided adhesive (the base layer is polyethylene terephthalate (PET) and the adhesive layer is polypropylene resin (PP)) is adhered to the first step of the electrode assembly so that the coverage area ratio of the adhesive on the first pole piece group is 20%, and the coverage area ratio on the second part of the second pole piece group that does not overlap with the first pole piece is 50%. A silicone filler is arranged in the accommodating space formed between the adhesive and the shell, and then liquid injection and chemical formation are carried out to obtain a finished battery cell.

[0168] Example 4

[0169] A first pole piece group and a second pole piece group are prepared according to the above method. After hot pressing and compounding, a single-sided adhesive (the base layer is polyethylene terephthalate (PET) and the adhesive layer is polypropylene resin (PP)) is adhered to the first step of the electrode assembly so that the coverage area ratio of the adhesive on the first pole piece group is 50%, and the coverage area ratio on the second part of the second pole piece group that does not overlap with the first pole piece is 50%. A silicone filler is arranged in the accommodating space formed between the adhesive and the shell, and then liquid injection and chemical formation are carried out to obtain a finished battery cell.

[0170] Example 5

[0171] The first pole piece group and the second pole piece group are prepared according to the above method. After hot pressing and compounding, a single-sided adhesive (the base layer is polyethylene terephthalate (PET) and the adhesive layer is polypropylene resin (PP)) is adhered to the first step of the electrode assembly, so that the coverage area ratio of the adhesive on the first pole piece group is 90%, and the coverage area ratio on the second part of the second pole piece group that does not overlap with the first pole piece is 50%. A silicone filler is arranged in the accommodating space formed between the adhesive and the shell, and then liquid injection and chemical formation are carried out to obtain a finished battery cell.

[0172] Example 6

[0173] A first pole piece group and a second pole piece group are prepared according to the above method. After hot pressing and compounding, a single-sided adhesive (the base layer is polyethylene terephthalate (PET) and the adhesive layer is polypropylene resin (PP)) is adhered to the first step of the electrode assembly so that the coverage area ratio of the adhesive on the first pole piece group is 100%, and the coverage area ratio on the second part of the second pole piece group that does not overlap with the first pole piece is 50%. A silicone filler is arranged in the accommodating space formed between the adhesive and the shell, and then liquid injection and chemical formation are carried out to obtain a finished battery cell.

[0174] Example 7

[0175] The first pole piece group and the second pole piece group are prepared according to the above method. After hot pressing and compounding, a single-sided adhesive (the base layer is polyethylene terephthalate (PET) and the adhesive layer is polypropylene resin (PP)) is adhered to the first step of the electrode assembly, so that the coverage area ratio of the adhesive on the first pole piece group is 50%, and the coverage area ratio on the second part of the second pole piece group that does not overlap with the first pole piece is 5%. A silicone filler is arranged in the accommodating space formed between the adhesive and the shell, and then liquid injection and chemical formation are carried out to obtain a finished battery cell.

[0176] Example 7

[0177] A first pole piece group and a second pole piece group are prepared according to the above method. After hot pressing and compounding, a single-sided adhesive (the base layer is polyethylene terephthalate (PET) and the adhesive layer is polypropylene resin (PP)) is adhered to the first step of the electrode assembly, so that the coverage area ratio of the adhesive on the first pole piece group is 50%, and the coverage area ratio on the second part of the second pole piece group that does not overlap with the first pole piece is 10%. A silicone filler is arranged in the accommodating space formed between the adhesive and the shell, and then liquid injection and chemical formation are carried out to obtain a finished battery cell.

[0178] Example 9

[0179] A first pole piece group and a second pole piece group are prepared according to the above method. After hot pressing and compounding, a single-sided adhesive (the base layer is polyethylene terephthalate (PET) and the adhesive layer is polypropylene resin (PP)) is adhered to the first step of the electrode assembly so that the coverage area ratio of the adhesive on the first pole piece group is 50%, and the coverage area ratio on the second part of the second pole piece group that does not overlap with the first pole piece is 20%. A silicone filler is arranged in the accommodating space formed between the adhesive and the shell, and then liquid injection and chemical formation are carried out to obtain a finished battery cell.

[0180] Example 10

[0181] The first pole piece group and the second pole piece group are prepared according to the above method. After hot pressing and compounding, a single-sided adhesive (the base layer is polyethylene terephthalate (PET) and the adhesive layer is polypropylene resin (PP)) is adhered to the first step of the electrode assembly, so that the coverage area ratio of the adhesive on the first pole piece group is 50%, and the coverage area ratio on the second part of the second pole piece group that does not overlap with the first pole piece is 90%. A silicone filler is arranged in the accommodating space formed between the adhesive and the shell, and then liquid injection and chemical formation are carried out to obtain a finished battery cell.

[0182] Embodiment 11

[0183] A first pole piece group and a second pole piece group are prepared according to the above method. After hot pressing and compounding, a single-sided adhesive (the base layer is polyethylene terephthalate (PET) and the adhesive layer is polypropylene resin (PP)) is adhered to the first step of the electrode assembly so that the coverage area ratio of the adhesive on the first pole piece group is 50%, and the coverage area ratio on the second part of the second pole piece group that does not overlap with the first pole piece is 100%. A silicone filler is arranged in the accommodating space formed between the adhesive and the shell, and then liquid injection and chemical formation are carried out to obtain a finished battery cell.

[0184] Example 12

[0185] A first pole piece group and a second pole piece group are prepared according to the above method. After hot pressing and compounding, a double-sided adhesive (the base layer is polyethylene terephthalate (PET) and the adhesive layer is polypropylene resin (PP)) is adhered to the first step of the electrode assembly, so that the coverage area ratio of the adhesive on the first pole piece group is 10%, and the coverage area ratio on the second part of the second pole piece group that does not overlap with the first pole piece is 50%. A silicone filler is arranged in the accommodating space formed between the adhesive and the shell, and then liquid injection and chemical formation are carried out to obtain a finished battery cell.

[0186] Example 13

[0187] A first pole piece group and a second pole piece group are prepared according to the above method. After hot pressing and compounding, a double-sided adhesive (the base layer is polyethylene terephthalate (PET) and the adhesive layer is polypropylene resin (PP)) is adhered to the first step of the electrode assembly so that the coverage area ratio of the adhesive on the first pole piece group is 20%, and the coverage area ratio on the second part of the second pole piece group that does not overlap with the first pole piece is 50%. A silicone filler is arranged in the accommodating space formed between the adhesive and the shell, and then liquid injection and chemical formation are carried out to obtain a finished battery cell.

[0188] Embodiment 14

[0189] A first pole piece group and a second pole piece group are prepared according to the above method. After hot pressing and compounding, a double-sided adhesive (the base layer is polyethylene terephthalate (PET) and the adhesive layer is polypropylene resin (PP)) is adhered to the first step of the electrode assembly so that the coverage area ratio of the adhesive on the first pole piece group is 50%, and the coverage area ratio on the second part of the second pole piece group that does not overlap with the first pole piece is 50%. A silicone filler is arranged in the accommodating space formed between the adhesive and the shell, and then liquid injection and chemical formation are carried out to obtain a finished battery cell.

[0190] Embodiment 15

[0191] A first pole piece group and a second pole piece group are prepared according to the above method. After hot pressing and compounding, a single-sided adhesive (the base layer is polyethylene terephthalate (PET) and the adhesive layer is polyacrylate) is adhered to the first step of the electrode assembly, so that the coverage area ratio of the adhesive on the first pole piece group is 50%, and the coverage area ratio on the second part of the second pole piece group that does not overlap with the first pole piece is 50%. A silicone filler is arranged in the accommodating space formed between the adhesive and the shell, and then liquid injection and chemical formation are carried out to obtain a finished battery cell.

[0192] Example 16

[0193] A first pole piece group and a second pole piece group are prepared according to the above method. After hot pressing and compounding, a single-sided adhesive (the base layer is polyimide and the adhesive layer is polyacrylate) is adhered to the first step of the electrode assembly, so that the coverage area ratio of the adhesive on the first pole piece group is 50%, and the coverage area ratio on the second part of the second pole piece group that does not overlap with the first pole piece is 50%. A silicone filler is arranged in the accommodating space formed between the adhesive and the shell, and then liquid injection and chemical formation are carried out to obtain a finished battery cell.

[0194] Embodiment 17

[0195] A first pole piece group and a second pole piece group are prepared according to the above method. After hot pressing and compounding, a single-sided adhesive (the base layer is polyethylene terephthalate (PET) and the adhesive layer is polypropylene resin (PP)) is adhered to the first step of the electrode assembly so that the coverage area ratio of the adhesive on the first pole piece group is 50%, and the coverage area ratio on the second part of the second pole piece group that does not overlap with the first pole piece is 50%. An epoxy resin filler is arranged in the accommodating space formed between the adhesive and the shell, and then liquid injection and chemical formation are carried out to obtain a finished battery cell.

[0196] Embodiment 18

[0197] A first pole piece group and a second pole piece group are prepared according to the above method. After hot pressing and compounding, a single-sided adhesive (the base layer is polyethylene terephthalate (PET) and the adhesive layer is polypropylene resin (PP)) is adhered to the first step of the electrode assembly so that the coverage area ratio of the adhesive on the first pole piece group is 50%, and the coverage area ratio on the second part of the second pole piece group that does not overlap with the first pole piece is 50%. A composite filler of silicone and aluminum oxide is arranged in the accommodating space formed between the adhesive and the shell, and then liquid injection and chemical formation are carried out to obtain a finished battery cell.

[0198] Refer to Table 1, in which S1 is the projection area of ​​the first section of the adhesive (the part covering the first pole piece group) along the first direction, S2 is the projection area of ​​the first pole piece group along the first direction, S3 is the projection area of ​​the second section of the adhesive (the part covering the second pole piece group) along the first direction, and S4 is the projection area of ​​the second part of the second pole piece group that does not overlap with the first pole piece group along the first direction.

[0199] Table 1

[0200]

[0201]

[0202] According to Table 1, the following conclusions can be drawn:

[0203] 1. Referring to Comparative Examples 1-3 and Examples 1-18, in Comparative Example 1 where neither a filler nor an adhesive is provided in the battery cell, the battery cell is prone to black spots due to lithium deposition, and the battery cell drop pass rate is low. In Comparative Example 2 where a filler is provided in the battery cell but no adhesive is provided, the filler can transfer external force to the second electrode group, reducing the possibility of black spots due to lithium deposition, but the battery cell drop pass rate is low. In Comparative Example 3 where an adhesive is provided in the battery cell but no filler is provided, the adhesive can improve the drop pass rate of the battery cell, but the battery cell is prone to black spots due to lithium deposition. Fillers and adhesives are provided in the battery cell, that is, the external force can be transferred to the second electrode group through the filler, reducing the possibility of black spots due to lithium deposition, and the adhesive can protect the electrode assembly, thereby improving the drop pass rate of the battery cell.

[0204] 2. Referring to Examples 1-6, as S1 / S2 increases, that is, the area of ​​the first section of the adhesive increases, the drop pass rate of the battery cell increases accordingly. When S1 / S2 is less than 10%, the bonding area of ​​the first section of the adhesive is small, and the effective protection area of ​​the electrode assembly is small, which will affect the drop pass rate of the battery cell. When S1 / S2 is greater than or equal to 10%, the bonding area of ​​the first section of the adhesive is large, and the effective protection area of ​​the electrode assembly is large, which is beneficial to improve the drop pass rate of the battery cell. When 20%≤S1 / S2≤90%, the drop pass rate of the battery cell is significantly improved, and the space occupied by the first section is small.

[0205] 3. See Examples 4, 7-11. As S3 / S4 increases, that is, the area of ​​the second section of the adhesive increases, the drop pass rate of the battery cell increases accordingly. When S3 / S4 is less than 10%, the bonding area of ​​the second section of the adhesive is small, and the effective protection area of ​​the electrode assembly is small, which will affect the drop pass rate of the battery cell. When S3 / S4 is greater than or equal to 10%, the bonding area of ​​the second section of the adhesive is large, and the effective protection area of ​​the electrode assembly is large, which is beneficial to improve the drop pass rate of the battery cell. When 20%≤S3 / S4≤90%, the drop pass rate of the battery cell is significantly improved, and the second section occupies less space.

[0206] 4. Referring to Examples 2-4 and 12-14, when the adhesive has a double-sided adhesive layer, the possibility of the electrode assembly being damaged by collision with the casing when the battery cell is subjected to force can be reduced, which is beneficial to improving the drop pass rate of the battery cell.

[0207] 5. Referring to Examples 4, 15 and 16, when the base material of the adhesive is polyethylene terephthalate or polyimide, the adhesive has higher strength; when the adhesive layer material of the adhesive is polypropylene resin or polyacrylate, the adhesive layer has higher bonding strength, so that the electrode assembly has better stability in the casing and the battery cell has a higher drop pass rate.

[0208] 6. Referring to Examples 4, 17 and 18, when the material of the filling piece is silicone, epoxy resin or a composite of silicone and aluminum oxide, the pressure transmission effect of the filling piece can be better, reducing the possibility of black spots caused by lithium deposition.

[0209] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application may be combined with each other.

[0210] The above are only preferred embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A battery cell, characterized in that: include: shell; An electrode assembly, the electrode assembly is accommodated in the housing, the electrode assembly is a laminated structure; the electrode assembly comprises a first electrode group and a second electrode group, the first electrode group and the second electrode group are stacked along a first direction, and the size of the first electrode group along the second direction is smaller than the size of the second electrode group along the second direction; When viewed along the first direction, the second pole piece group has a first surface facing the first pole piece group, the second pole piece group includes a first portion overlapping with a projection of the first pole piece group, and a second portion not overlapping with the first pole piece group, a side wall of the first pole piece group close to the second portion in the second direction forms a first step with the first surface of the second portion; and the housing is formed with a second step corresponding to the first step; An adhesive member adhered to the first step, and an accommodation space is formed between the adhesive member and the second step along the second direction; A filling piece, arranged in the accommodation space; The first direction is parallel to a thickness direction of the electrode assembly, and the first direction is perpendicular to the second direction.

2. The battery cell according to claim 1, characterized in that: The adhesive comprises a first section, a second section and a third section, the first section is adhered to a side of the first pole piece group away from the second pole piece group along the first direction, the second section is adhered to the second part, and the third section connects the first section and the second section.

3. The battery cell according to claim 2, characterized in that: Along the first direction, the projection area of ​​the first segment is S1, and the projection area of ​​the first pole piece group is S2, satisfying 10%≤S1 / S2≤100%.

4. The battery cell according to claim 3, characterized in that: 20%≤S1 / S2≤90%.

5. The battery cell according to claim 2, characterized in that: Along the first direction, a projection area of ​​the second segment is S3, and a projection area of ​​the second portion is S4, satisfying 10%≤S3 / S4≤100%.

6. The battery cell according to claim 5, characterized in that: 20%≤S3 / S4≤90%.

7. The battery cell according to claim 2, characterized in that: The shell includes a first wall and a second wall arranged opposite to each other along the first direction, the first wall includes a main body wall and a step wall, along the second direction, the step wall is located at one end of the main body wall, the step wall is recessed relative to the main body wall in a direction close to the second wall, and the step wall is connected to the main body wall through a connecting wall; the second pole piece group is arranged between the step wall and the second wall, and the first pole piece group is arranged between the main body wall and the second pole piece group; the second section, the third section, the connecting wall and the main body wall enclose the accommodating space.

8. The battery cell according to claim 1, characterized in that: The second pole piece group includes a first area, and along the first direction, the first area corresponds to the accommodation space; Along the first direction, the projection area of ​​the first region is S5, and the projection area of ​​the second pole piece group is S6, satisfying 0.1%≤S5 / S6≤20%.

9. The battery cell according to claim 1, characterized in that: The filling piece is connected to the housing and / or the second pole piece group.

10. The battery cell according to claim 1, characterized in that: The outer shell is a hard shell, and along the first direction, a minimum distance between the filler and the outer shell is H, satisfying 0≤H≤5mm.

11. The battery cell according to claim 10, characterized in that: 0.4mm≤H≤3.5mm.

12. The battery cell according to claim 1, characterized in that: The adhesive member includes a base layer and a first adhesive layer, wherein the first adhesive layer is disposed on one side of the base layer along a thickness direction thereof, and at least a portion of the first adhesive layer is bonded to the electrode assembly.

13. The battery cell according to claim 12, characterized in that: The adhesive member further includes a second adhesive layer, which is disposed on a side of the base layer opposite to the first adhesive layer along a thickness direction of the base layer, and a portion of the second adhesive layer is bonded to the housing.

14. The battery cell according to claim 13, characterized in that: The base layer includes at least one of polyethylene terephthalate, polyimide, polyethylene, and polypropylene; The first adhesive layer and / or the second adhesive layer include at least one of polyacrylic resin, polyethylene resin, polypropylene resin, polyethylene-propylene copolymer, epoxy resin, polyamide, styrene-butadiene rubber, butyl rubber, styrene-butadiene-styrene copolymer, styrene-isoprene-styrene copolymer, ethylene-acrylic acid copolymer, and ethylene-vinyl acetate copolymer.

15. The battery cell according to claim 1, characterized in that: The filler comprises an organic material; or, The filler comprises a composite of organic material and inorganic material.

16. The battery cell according to claim 15, characterized in that: The organic material comprises at least one of silicone, polyurethane, epoxy resin, polyethylene, polypropylene, ethylene-acrylic acid copolymer, ethylene-vinyl acetate copolymer, polyester, and polyamide; The inorganic material includes at least one of aluminum oxide, 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, and lithium lanthanum titanate.

17. The battery cell according to claim 1, characterized in that: Along the first direction, the projection area of ​​the first pole piece group is S2, and the projection area of ​​the second pole piece group is S6, satisfying 20%≤S2 / S6≤90%.

18. An electrical equipment, characterized in that: The invention comprises a battery cell as described in any one of claims 1 to 17, wherein the battery cell is used to provide electrical energy.

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