Battery cell and electric equipment

Abstract

The invention provides a battery cell and electric equipment, the battery cell comprises a shell and an electrode assembly, and the electrode assembly is accommodated in the shell; the shell comprises a first wall and a second wall which are oppositely arranged in the thickness direction of the battery cell, the first wall comprises a first sub-wall, a second sub-wall and a first connecting wall, the second sub-wall protrudes out of the first sub-wall in the direction away from the second wall, and the first connecting wall is connected with the first sub-wall and the second sub-wall; the distance between the first sub-wall and the second sub-wall is H1 along the thickness direction of the battery cell, and H1 is more than 0mm and less than or equal to 1.5 mm; and the included angle between the first connecting wall and the thickness direction of the battery cell is theta1 which is more than 0 degree and less than or equal to 45 degrees. According to the technical scheme, the fitting property of the shell and the electrode assembly can be good, the gap between the first connecting wall and the electrode assembly is small, the energy density of the battery cell can be improved, the electrode assembly is not prone to shaking in the shell, and the stability of the battery cell is good.

Description

Technical Field

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

[0002] With the rapid development of new energy technologies, batteries have been widely used in electronic equipment, electric vehicles, electric two-wheelers, power tools, etc. The requirements for battery quality, safety, and miniaturization are becoming increasingly higher.

[0003] For soft-pack batteries with a step shape, the packaging film is generally punched to form the step shape. However, for some packaging films, especially those with a small step depth, the punching is difficult to form. As a result, after the packaging film is prepared to form an outer shell, the outer shell and the electrode assembly have poor fit, and a large gap is formed between the step of the outer shell and the electrode assembly, resulting in a loss of energy density of the battery. In addition, the electrode assembly is prone to shaking in the outer shell, resulting in poor stability of the battery. Summary of the invention

[0004] The present application provides a battery cell and an electrical device, which can improve the energy density and stability of the battery cell.

[0005] In a first aspect, the present application provides a battery cell, the battery cell comprising a shell and an electrode assembly, wherein the electrode assembly is accommodated in the shell. The shell comprises a first wall and a second wall arranged opposite to each other along the thickness direction of the battery cell. The first wall comprises a first sub-wall, a second sub-wall and a first connecting wall. In a direction away from the second wall, the second sub-wall protrudes from the first sub-wall, and the first connecting wall connects the first sub-wall and the second sub-wall. In the thickness direction of the battery cell, the distance between the first sub-wall and the second sub-wall is H1, satisfying 0mm

[0006] ​In the above technical solution, the electrode assembly is accommodated in the shell, so that the shell can play a protective role on the electrode assembly; the shell includes a first wall and a second wall arranged oppositely along the thickness direction of the battery cell, the first wall includes a first sub-wall, a second sub-wall and a first connecting wall, the second sub-wall protrudes from the first sub-wall in the direction away from the second wall, and the first connecting wall connects the first sub-wall and the second sub-wall, so that a step structure is formed between the first sub-wall and the second sub-wall, which can be used to accommodate other components when the battery cell is assembled in the electrical equipment; the distance H1 between the first sub-wall and the second sub-wall along the thickness direction of the battery cell satisfies 0mm

[0007] In some embodiments of the present application, 0mm

[0008] ​​In the above technical scheme, when θ1 is greater than or equal to 20°, it is convenient to install the electrode assembly into the shell, reducing the possibility of the electrode assembly and the shell being squeezed and damaged during the installation process; when θ1 is less than or equal to 45°, it can further make the battery cell suitable for the case where the step depth is less than or equal to 1mm, so that the application range of the battery cell is wider, and when the step depth is less than or equal to 1mm, the angle θ1 between the first connecting wall and the thickness direction of the battery cell is smaller, which can further make the fit between the shell and the electrode assembly better, and the gap between the first connecting wall and the electrode assembly is smaller, which is conducive to further improving the energy density of the battery cell, and the electrode assembly is not easy to shake in the shell, further making the stability of the battery cell better; therefore, when 0mm

[0009] In some embodiments of the present application, the electrode assembly includes a first electrode plate group and a second electrode plate group, the first electrode plate group and the second electrode plate group are stacked, the size of the first electrode plate group along the first direction is larger than the size of the second electrode plate group along the first direction; the first electrode plate group is located between the first sub-wall and the second wall, and the second electrode plate group is located between the first electrode plate group and the second sub-wall; the first direction is perpendicular to the thickness direction of the battery cell.

[0010] In the above technical solution, by making the electrode assembly include a first electrode plate group and a second electrode plate group, the first electrode plate group and the second electrode plate group are stacked, and the size of the first electrode plate group along the first direction is larger than the size of the second electrode plate group along the first direction, so that the first electrode plate group and the second electrode plate group can form a step structure together to adapt to the step structure of the outer shell; the first electrode plate group is located between the first sub-wall and the second wall, and the second electrode plate group is located between the first electrode plate group and the second sub-wall, so that the second electrode plate group is accommodated at the step structure of the outer shell to adapt to the first wall and the second wall of the outer shell.

[0011] In some embodiments of the present application, the first sub-wall has a first end close to the first connecting wall, the second electrode plate group includes a second positive electrode plate and a second negative electrode plate stacked together, and along the first direction, the distance between one end of the second negative electrode plate close to the first connecting wall and the first end is D, satisfying D≤1.5mm.

[0012] ​In the above technical solution, the first sub-wall has a first end close to the first connecting wall, the second electrode plate group includes a second positive electrode plate and a second negative electrode plate stacked together, and along the first direction, the distance D between one end of the second negative electrode plate close to the first connecting wall and the first end satisfies D≤1.5mm, so that along the first direction, the gap between the first connecting wall and the electrode assembly is smaller, which is beneficial to improving the energy density of the battery cell, and makes it difficult for the electrode assembly to shake in the outer casing, and the stability of the battery cell is better.

[0013] In some embodiments of the present application, along the thickness direction of the battery cell, the distance between the first sub-wall and the second wall is T1, and the distance between the second sub-wall and the second wall is T2, satisfying T1<T2.

[0014] In the above technical solution, by making the distance T1 between the first sub-wall and the second wall and the distance T2 between the second sub-wall and the second wall satisfy T1<T2 along the thickness direction of the battery cell, a step structure can be formed between the first sub-wall and the second sub-wall, which can be used to accommodate other components when the battery cell 10 is assembled in the electrical equipment, thereby adapting to different electrical equipment.

[0015] In some embodiments of the present application, one end of the first connecting wall is connected to the first sub-wall through a first arc transition portion, and the other end of the first connecting wall is connected to the second sub-wall through a second arc transition portion.

[0016] In the above technical solution, by connecting one end of the first connecting wall to the first sub-wall through the first arc transition portion, and connecting the other end of the first connecting wall to the second sub-wall through the second arc transition portion, the preparation and forming of the first wall can be facilitated, and the force distribution of the first arc transition portion and the second arc transition portion is more uniform when subjected to force, and it is not easy to cause stress concentration, thereby reducing the possibility of the first connecting wall being damaged by force and is not easy to cause damage to other components.

[0017] In some embodiments of the present application, the first wall also includes a third sub-wall and a second connecting wall, the third sub-wall is located on a side of the second sub-wall away from the first sub-wall, the second sub-wall protrudes out of the third sub-wall in a direction away from the second wall, and the second connecting wall connects the second sub-wall and the third sub-wall; along the thickness direction of the battery cell, the distance between the second sub-wall and the third sub-wall is H2, satisfying 0mm<H2≤1.5mm; the angle between the second connecting wall and the thickness direction of the battery cell is θ2, satisfying 0°<θ2≤45°.

[0018] In the above technical solution, the first wall also includes a third sub-wall and a second connecting wall, the third sub-wall is located on the side of the second sub-wall away from the first sub-wall, the second sub-wall protrudes from the third sub-wall in the direction away from the second wall, and the second connecting wall connects the second sub-wall and the third sub-wall, so that a step structure is formed between the second sub-wall and the third sub-wall, which can be used to accommodate other components when the battery cell is assembled on the electrical equipment; the distance between the second sub-wall and the third sub-wall along the thickness direction of the battery cell is H2, satisfying 0mm<H2≤1.5mm; when θ2 is greater than 0°, it is convenient to install the electrode assembly into the outer shell, reducing the possibility of the electrode assembly and the outer shell being squeezed and damaged during the installation process; when θ2≤45°, the battery cell can be suitable for a step depth less than or equal to 1.5mm In the case where the step depth is less than or equal to 1.5 mm, the angle θ2 between the second connecting wall and the thickness direction of the battery cell is smaller, which can make the outer shell and the electrode assembly fit better, and the gap between the second connecting wall and the electrode assembly is smaller, which is beneficial to improve the energy density of the battery cell, and the electrode assembly is not easy to shake in the outer shell, so that the stability of the battery cell is better; therefore, when 0°<θ2≤45°, it can facilitate the installation of the electrode assembly into the outer shell and reduce the possibility of damage to the electrode assembly and the outer shell during installation, and can also make the outer shell and the electrode assembly fit better, and the gap between the second connecting wall and the electrode assembly is smaller, which is beneficial to improve the energy density of the battery cell, and the electrode assembly is not easy to shake in the outer shell, so that the stability of the battery cell is better.

[0019] In some embodiments of the present application, an insulating layer is disposed between the first wall and the electrode assembly, and the insulating layer at least covers the inner surface of the first connecting wall.

[0020] In the above technical solution, an insulating layer is provided between the first wall and the electrode assembly, and the insulating layer at least covers the inner surface of the first connecting wall, so that the insulating layer can play an insulating role between the outer shell and the electrode assembly, and can also play a protective role for the outer shell, thereby reducing the possibility of the electrode assembly damaging the first connecting wall.

[0021] In a second aspect, the present application provides an electrical device, comprising a battery cell as described above, wherein the battery cell is used to provide electrical energy.

[0022] In a third aspect, the present application provides a method for preparing a battery cell, comprising:

[0023] A battery cell is provided, the battery cell comprising a shell and an electrode assembly, wherein the electrode assembly is accommodated in the shell; the shell comprises a first wall and a second wall arranged opposite to each other along a thickness direction of the battery cell, the first wall comprises a first sub-wall, a second sub-wall and a first connecting wall, the second sub-wall protrudes from the first sub-wall in a direction away from the second wall, and the first connecting wall connects the first sub-wall and the second sub-wall; along the thickness direction of the battery cell, a distance between the first sub-wall and the second sub-wall is H1, satisfying 0mm

[0024] The first connecting wall of the battery cell is shaped by the pressing block so that an angle θ1 between the first connecting wall and the thickness direction of the battery cell satisfies 0°<θ1≤45°.

[0025] In the above technical solution, the electrode assembly is accommodated in the shell, so that the shell can protect the electrode assembly; the shell includes a first wall and a second wall arranged opposite to each other along the thickness direction of the battery cell, the first wall includes a first sub-wall, a second sub-wall and a first connecting wall, the second sub-wall protrudes from the first sub-wall in the direction away from the second wall, and the first connecting wall connects the first sub-wall and the second sub-wall, so that a step structure is formed between the first sub-wall and the second sub-wall, which can be used to accommodate other components when the battery cell is assembled in an electrical device; the distance H1 between the first sub-wall and the second sub-wall along the thickness direction of the battery cell satisfies 0mm BRIEF DESCRIPTION OF THE DRAWINGS

[0026] 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.

[0027] ​​Figure 1 A schematic structural diagram of a battery cell from one perspective provided in some embodiments of the present application;

[0028] Figure 2 for Figure 1 The schematic diagram of the cross-sectional structure of the battery cell along AA shown;

[0029] Figure 3 for Figure 2 A schematic diagram of a partial enlarged structure of a cell at position B shown;

[0030] Figure 4 A schematic structural diagram of a battery cell from one perspective provided in some other embodiments of the present application;

[0031] Figure 5 for Figure 4 The schematic diagram of the cross-sectional structure of the battery cell along CC is shown;

[0032] Figure 6 for Figure 5 A schematic diagram of a partial enlarged structure at D of the battery cell shown;

[0033] Figure 7 A schematic diagram of a process for preparing a battery cell according to some embodiments of the present application;

[0034] Figure 8 A schematic diagram of a partially enlarged structure of a battery cell before shaping provided in some embodiments of the present application;

[0035] Fig. 9 A schematic diagram of the three-dimensional structure of a shaping device and a battery cell provided in some embodiments of the present application.

[0036] Icon: 10-battery core; 100-housing; 110-first wall; 111-first sub-wall; 112-second sub-wall; 113-first connecting wall; 1131-first main body; 1132-first arc transition part; 1133-second arc transition part; 114-third sub-wall; 115-second connecting wall; 1151-second main body; 1152-third transition part; 1153-fourth transition part; 120-second wall ; 130-insulating layer; 140-first sealing part; 150-second sealing part; 200-electrode assembly; 210-first electrode plate group; 211-first positive electrode plate; 212-first negative electrode plate; 220-second electrode plate group; 221-second positive electrode plate; 222-second negative electrode plate; 230-first electrical connector; 240-second electrical connector; X-thickness direction of the battery cell; Y-first direction; Z-second direction. DETAILED DESCRIPTION

[0037] 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.

[0038] 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.

[0039] 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.

[0040] 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.

[0041] 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.

[0042] With the development of the new energy industry, batteries are gradually developing towards high energy density, high power density and multi-function. In some electrical equipment, it is necessary to adapt to special-shaped battery cells. For example, electrical equipment with folding screens needs to adapt to battery cells with stepped surfaces so that components such as circuit boards can be set at the stepped parts of the battery cells.

[0043] In a step-shaped soft-pack battery cell, a shell is generally formed by punching holes in the packaging film. The first wall of the shell forms a first sub-wall, a second sub-wall and a first connecting wall. The second sub-wall protrudes from the first sub-wall. The first connecting wall connects the first sub-wall and the second sub-wall, and a step structure is formed between the first sub-wall and the second sub-wall. However, for some packaging films, especially those with a small step depth, the angle between the first connecting wall and the thickness direction of the battery cell is large after punching holes, which makes it difficult to form the holes. This will cause poor fit between the shell and the electrode assembly, and a large gap will be formed between the step of the shell and the electrode assembly, resulting in a loss of energy density of the battery. In addition, the electrode assembly is prone to shaking in the shell, resulting in poor stability of the battery.

[0044] In order to improve the energy density and stability of a battery cell, the present application provides a battery cell, which includes a shell and an electrode assembly, wherein the electrode assembly is accommodated in the shell; the shell includes a first wall and a second wall arranged opposite to each other along the thickness direction of the battery cell, the first wall includes a first sub-wall, a second sub-wall and a first connecting wall, the second sub-wall protrudes from the first sub-wall along the direction away from the second wall, and the first connecting wall connects the first sub-wall and the second sub-wall; along the thickness direction of the battery cell, the distance between the first sub-wall and the second sub-wall is H1, satisfying 0mm

[0045] ​In the battery cell shell of this structure, the electrode assembly is accommodated in the shell, so that the shell can protect the electrode assembly; the shell includes a first wall and a second wall arranged opposite to each other along the thickness direction of the battery cell, the first wall includes a first sub-wall, a second sub-wall and a first connecting wall, the second sub-wall protrudes from the first sub-wall in the direction away from the second wall, and the first connecting wall connects the first sub-wall and the second sub-wall, so that a step structure is formed between the first sub-wall and the second sub-wall, which can be used to accommodate other components when the battery cell is assembled in an electrical device; the distance H1 between the first sub-wall and the second sub-wall along the thickness direction of the battery cell satisfies 0mm

[0046] The battery cell provided in the embodiment of the present application can be a secondary battery or a primary battery, for example, a lithium ion battery, a sodium ion battery or a magnesium ion battery, etc., which is not limited in the embodiment of the present application. The electrochemical device can be cylindrical, flat, rectangular or other shapes, etc., which is not limited in the embodiment of the present application.

[0047] 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.

[0048] See also Figures 1 to 3 , Figure 1 A schematic diagram of the structure of a battery cell from one perspective provided in some embodiments of the present application, Figure 2 for Figure 1 The schematic diagram of the cross-sectional structure of the battery cell along AA shown; Figure 3 for Figure 2 A schematic diagram of the local enlarged structure of the battery cell at B is shown.

[0049] ​The embodiment of the present application provides a battery cell 10 , which includes a housing 100 and an electrode assembly 200 , wherein the electrode assembly 200 is accommodated in the housing 100 .

[0050] By accommodating the electrode assembly 200 in the housing 100 , the housing 100 can protect the electrode assembly 200 .

[0051] The battery cell 10 includes a housing 100, an electrode assembly and an electrolyte, and the housing 100 is used to accommodate the electrode assembly and the electrolyte. The electrode assembly 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, and the positive electrode active material layer is coated on the surface of the positive electrode collector. 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 electric energy of the positive electrode sheet through the positive electrode ear. The positive electrode ear and the positive electrode collector can also be set separately and then connected as one, for example, the positive electrode ear and the positive electrode collector are connected as one by welding connection, conductive glue connection, etc. Taking lithium-ion batteries 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 plate includes a negative electrode current collector and a negative electrode active material layer. The negative electrode active material layer is coated on the surface of the negative electrode current collector. The portion of the negative electrode current collector that is not coated with the negative electrode active material layer serves as a negative electrode ear, so as to realize the input or output of electric energy of the negative electrode plate through the negative electrode ear. The negative electrode ear and the negative electrode current collector can also be separately arranged and then connected as one, for example, the negative electrode ear and the negative electrode current collector are connected as one by welding connection, conductive adhesive connection, etc. The material of the negative electrode current collector can be copper, and the negative electrode active material can be carbon material or silicon material, etc. The material of the isolation membrane can be polypropylene (PP) or polyethylene (PE), etc. The electrolyte can include an organic solvent, an electrolyte lithium salt, etc.

[0052] In some embodiments, the electrode assembly can be a stacked electrode assembly, in which at least one positive electrode sheet, at least one negative electrode sheet and at least one isolation membrane are stacked in a certain order, and the isolation membrane is arranged between the positive electrode sheet and the negative electrode sheet to insulate and separate the positive electrode sheet and the negative electrode sheet, thereby reducing the risk of short circuit of the battery cell 10.

[0053] In some embodiments, the electrode assembly may also be a wound electrode assembly. The positive electrode sheet, the negative electrode sheet and the separator are stacked in a certain order and wound around a winding center axis to form a wound electrode assembly. The separator is arranged between the positive electrode sheet and the negative electrode sheet, and the separator is used to insulate and separate the positive electrode sheet and the negative electrode sheet.

[0054] In some embodiments, the housing 100 may be made of an aluminum-plastic film.

[0055] In some embodiments, the housing 100 includes a first wall 110 and a second wall 120 that are relatively arranged along the thickness direction X of the battery cell. The first wall 110 includes a first sub-wall 111, a second sub-wall 112 and a first connecting wall 113. In a direction away from the second wall 120, the second sub-wall 112 protrudes from the first sub-wall 111, and the first connecting wall 113 connects the first sub-wall 111 and the second sub-wall 112.

[0056] The housing 100 includes a first wall 110 and a second wall 120 that are relatively arranged along the thickness direction X of the battery cell. The first wall 110 includes a first sub-wall 111, a second sub-wall 112 and a first connecting wall 113. In the direction away from the second wall 120, the second sub-wall 112 protrudes from the first sub-wall 111. The first connecting wall 113 connects the first sub-wall 111 and the second sub-wall 112, so that a step structure is formed between the first sub-wall 111 and the second sub-wall 112, which can be used to accommodate other components when the battery cell 10 is assembled in an electrical device.

[0057] In some embodiments, along the thickness direction X of the battery cell, the distance between the first sub-wall 111 and the second sub-wall 112 is H1, satisfying 0mm

[0058] When θ1 is greater than 0°, it is easy to install the electrode assembly 200 into the shell 100, reducing the possibility of the electrode assembly 200 and the shell 100 being squeezed and damaged during the installation process; when θ1≤45°, the battery cell 10 can be applied to the case where the step depth is less than or equal to 1.5 mm, and when the step depth is less than or equal to 1.5 mm, the angle θ1 between the first connecting wall 113 and the thickness direction X of the battery cell is small, which can make the shell 100 and the electrode assembly 200 fit better, and the gap between the first connecting wall 113 and the electrode assembly 200 is small, which is conducive to improving the energy density of the battery cell 10. degree, and the electrode assembly 200 is not easy to shake in the shell 100, so that the stability of the battery cell 10 is better; therefore, when 0°<θ1≤45°, it is easy to install the electrode assembly 200 in the shell 100, reducing the possibility of the electrode assembly 200 and the shell 100 being squeezed and damaged during the installation process, and the shell 100 and the electrode assembly 200 can be better fitted, and the gap between the first connecting wall 113 and the electrode assembly 200 is smaller, which is beneficial to improving the energy density of the battery cell 10, and the electrode assembly 200 is not easy to shake in the shell 100, so that the stability of the battery cell 10 is better.

[0059] ​In some embodiments, the first connecting wall 113 includes a first main body 1131, a first transition portion, and a second transition portion. The surface of the first main body 1131 is arranged in a plane. The first transition portion is connected to the first sub-wall 111, and the second transition portion is connected to the second sub-wall 112. The angle θ1 between the first connecting wall 113 and the thickness direction X of the battery cell is the angle between the plane where the first main body 1131 is located and the direction from the second wall 120 to the first wall 110 in the thickness direction X of the battery cell.

[0060] In some embodiments, 0 mm < H1 ≤ 1 mm. For example, H1 may be 1 mm, 0.8 mm, or 0.7 mm.

[0061] In some embodiments, 20°≤θ1≤45°. For example, θ1 may be 20°, 30°, or 45°.

[0062] When θ1 is greater than or equal to 20°, it is easy to install the electrode assembly 200 into the shell 100, reducing the possibility of the electrode assembly 200 and the shell 100 being squeezed and damaged during the installation process; when θ1 is less than or equal to 45°, it can further enable the battery cell 10 to be applicable to the case where the step depth is less than or equal to 1 mm, so that the battery cell 10 has a wider range of applications, and when the step depth is less than or equal to 1 mm, the angle θ1 between the first connecting wall 113 and the thickness direction of the battery cell 10 is smaller, which can further make the shell 100 and the electrode assembly 200 fit better, and the gap between the first connecting wall 113 and the electrode assembly 200 is smaller, which is conducive to further improving the battery cell 10. Energy density, and the electrode assembly 200 is not easy to shake in the shell 100, which further improves the stability of the battery cell 10; therefore, when 0mm

[0063] In some embodiments, the electrode assembly 200 includes a first electrode set 210 and a second electrode set 220, the first electrode set 210 and the second electrode set 220 are stacked, and the size of the first electrode set 210 along the first direction Y is greater than the size of the second electrode set 220 along the first direction Y. The first electrode set 210 is located between the first sub-wall 111 and the second wall 120, and the second electrode set 220 is located between the first electrode set 210 and the second sub-wall 112.

[0064] The first direction Y is perpendicular to the thickness direction X of the battery cell.​

[0065] By making the electrode assembly 200 include a first electrode plate group 210 and a second electrode plate group 220, the first electrode plate group 210 and the second electrode plate group 220 are stacked, and the size of the first electrode plate group 210 along the first direction Y is larger than the size of the second electrode plate group 220 along the first direction Y, the first electrode plate group 210 and the second electrode plate group 220 can form a step structure together to adapt to the step structure of the outer shell 100; the first electrode plate group 210 is located between the first sub-wall 111 and the second wall 120, and the second electrode plate group 220 is located between the first electrode plate group 210 and the second sub-wall 112, so that the second electrode plate group 220 is accommodated at the step structure of the outer shell 100 to adapt to the first wall 110 and the second wall 120 of the outer shell 100.

[0066] In some embodiments, the first electrode sheet group 210 includes a plurality of first positive electrode sheets 211 and a plurality of first negative electrode sheets 212 stacked in layers, so that the energy density of the first electrode sheet group 210 is relatively high.

[0067] In some other embodiments, the first electrode plate group 210 may include a first positive electrode plate 211 and a first negative electrode plate 212 which are stacked.

[0068] In some embodiments, the first sub-wall 111 has a first end close to the first connecting wall 113, the second electrode set 220 includes a second positive electrode sheet 221 and a second negative electrode sheet 222 stacked, and along the first direction Y, the distance between the end of the second negative electrode sheet 222 close to the first connecting wall 113 and the first end is D, satisfying D≤1.5 mm. For example, D can be 1.5 mm, 1.2 mm, or 1 mm, etc.

[0069] The first sub-wall 111 has a first end close to the first connecting wall 113, and the second electrode plate group 220 includes a second positive electrode plate 221 and a second negative electrode plate 222 that are stacked. Along the first direction Y, the distance D between one end of the second negative electrode plate 222 close to the first connecting wall 113 and the first end satisfies D≤1.5mm, so that along the first direction Y, the gap between the first connecting wall 113 and the electrode assembly 200 is smaller, which is beneficial to improving the energy density of the battery cell 10, and makes it difficult for the electrode assembly 200 to shake in the housing 100, and the stability of the battery cell 10 is better.

[0070] In some embodiments, the second electrode plate group 220 may include a second positive electrode plate 221 and a second negative electrode plate 222 which are stacked, so that the second electrode plate group 220 has a smaller thickness and can be accommodated between the first electrode plate group 210 and the second sub-wall 112 .

[0071] In other embodiments, the second electrode plate group 220 may also include a plurality of second positive electrode plates 221 and a plurality of second negative electrode plates 222 that are stacked, so that the energy density of the second electrode plate group 220 is higher.

[0072] In some embodiments, along the thickness direction X of the battery cell, the distance between the first sub-wall 111 and the second wall 120 is T1, and the distance between the second sub-wall 112 and the second wall 120 is T2, satisfying T1<T2. For example, T1 may be 0.9*T2, 0.7*T2, or 0.5*T2.

[0073] By ensuring that along the thickness direction X of the battery cell, the distance T1 between the first sub-wall 111 and the second wall 120, and the distance T2 between the second sub-wall 112 and the second wall 120 satisfy T1<T2, a step structure can be formed between the first sub-wall 111 and the second sub-wall 112, which can be used to accommodate other components when the battery cell 1010 is assembled in an electrical device, thereby adapting to different electrical devices.

[0074] In some embodiments, the surface of the second wall 120 is arranged in a plane, so that the housing 100 forms a step structure only on one side of the thickness direction X of the battery core to adapt to the electrical equipment.

[0075] In some embodiments, one end of the first connecting wall 113 is connected to the first sub-wall 111 through a first arc transition portion 1132 , and the other end of the first connecting wall 113 is connected to the second sub-wall 112 through a second arc transition portion 1133 .

[0076] By connecting one end of the first connecting wall 113 to the first sub-wall 111 through the first arc transition portion 1132, and connecting the other end of the first connecting wall 113 to the second sub-wall 112 through the second arc transition portion 1133, the preparation and forming of the first wall 110 can be facilitated, and the force distribution of the first arc transition portion 1132 and the second arc transition portion 1133 is more uniform when subjected to force, and is less likely to cause stress concentration, thereby reducing the possibility of the first connecting wall 113 being damaged by force and less likely to cause damage to other components.

[0077] See also Figures 4 to 6 , Figure 4 A schematic diagram of the structure of a battery cell from one perspective provided in some other embodiments of the present application, Figure 5 for Figure 4 The schematic diagram of the cross-sectional structure of the battery cell along CC is shown; Figure 6 for Figure 5 A schematic diagram of the local enlarged structure of the battery cell at D is shown.

[0078] In some embodiments, the first wall 110 also includes a third sub-wall 114 and a second connecting wall 115. The third sub-wall 114 is located on a side of the second sub-wall 112 away from the first sub-wall 111. In a direction away from the second wall 120, the second sub-wall 112 protrudes from the third sub-wall 114. The second connecting wall 115 connects the second sub-wall 112 and the third sub-wall 114.

[0079] By making the first wall 110 also include a third sub-wall 114 and a second connecting wall 115, the third sub-wall 114 is located on a side of the second sub-wall 112 away from the first sub-wall 111, and the second sub-wall 112 protrudes from the third sub-wall 114 in a direction away from the second wall 120. The second connecting wall 115 connects the second sub-wall 112 and the third sub-wall 114, so that a step structure is formed between the second sub-wall 112 and the third sub-wall 114, which can be used to accommodate other components when the battery cell 10 is assembled in an electrical device.

[0080] In some embodiments, along the thickness direction X of the battery cell, the distance between the second sub-wall 112 and the third sub-wall 114 is H2, satisfying 0mm<H2≤1.5mm. For example, H2 may be 1.5mm, 1.2mm or 1mm. The angle between the second connecting wall 115 and the thickness direction X of the battery cell is θ2, satisfying 0°<θ2≤45°. For example, θ2 may be 45°, 40° or 35°, etc.

[0081] When θ2 is greater than 0°, it is easy to install the electrode assembly 200 into the shell 100, reducing the possibility of the electrode assembly 200 and the shell 100 being squeezed and damaged during the installation process; when θ2 is less than or equal to 45°, the battery cell 10 can be applied to the case where the step depth is less than or equal to 1.5 mm, and when the step depth is less than or equal to 1.5 mm, the angle θ2 between the second connecting wall 115 and the thickness direction X of the battery cell is small, which can make the shell 100 and the electrode assembly 200 fit better, and the gap between the second connecting wall 115 and the electrode assembly 200 is small, which is conducive to improving the energy of the battery cell 10. The energy density of the battery cell 10 is improved, and the electrode assembly 200 is not easy to shake in the shell 100, so that the stability of the battery cell 10 is better; therefore, when 0°<θ2≤45°, it is easy to install the electrode assembly 200 in the shell 100, reducing the possibility of the electrode assembly 200 and the shell 100 being squeezed and damaged during the installation process, and the shell 100 and the electrode assembly 200 can be better fitted, and the gap between the second connecting wall 115 and the electrode assembly 200 is smaller, which is beneficial to improving the energy density of the battery cell 10, and the electrode assembly 200 is not easy to shake in the shell 100, so that the stability of the battery cell 10 is better.

[0082] In some embodiments, the second connecting wall 115 includes a second main body 1151, a third transition portion 1152, and a fourth transition portion 1153. The surface of the second main body 1151 is arranged in a plane, the third transition portion 1152 is connected to the third sub-wall 114, and the fourth transition portion 1153 is connected to the second sub-wall 112. The angle θ1 between the second connecting wall 115 and the thickness direction X of the battery cell is the angle between the plane where the second main body 1151 is located and the direction from the second wall 120 to the first wall 110 in the thickness direction X of the battery cell.

[0083] In some embodiments, 0 mm < H2 ≤ 1 mm. For example, H2 may be 1 mm, 0.8 mm, or 0.7 mm.

[0084] In some embodiments, 20°≤θ2≤45°. For example, θ2 may be 20°, 30°, or 45°.

[0085] By making 0mm

[0086] In some embodiments, an insulating layer 130 is disposed between the first wall 110 and the electrode assembly 200 , and the insulating layer 130 at least covers the inner surface of the first connecting wall 113 .

[0087] By setting an insulating layer 130 between the first wall 110 and the electrode assembly 200, the insulating layer 130 at least covers the inner surface of the first connecting wall 113, so that the insulating layer 130 can play an insulating role between the outer shell 100 and the electrode assembly 200, and can also play a protective role for the outer shell 100, thereby reducing the possibility of the electrode assembly 200 damaging the first connecting wall 113.

[0088] In some embodiments, the insulating layer 130 may cover the inner surface of the first wall 110 , so that the insulating layer 130 can insulate the outer shell 100 and the electrode assembly 200 , and can also protect the outer shell 100 , thereby reducing the possibility of the electrode assembly 200 damaging the first wall 110 .

[0089] ​In some embodiments, the insulating layer 130 may cover the inner surface of the housing 100 , so that the insulating layer 130 can insulate the housing 100 and the electrode assembly 200 , and can also protect the housing 100 , thereby reducing the possibility of the electrode assembly 200 damaging the housing 100 .

[0090] In some embodiments, the insulating layer 130 may include at least one of ethylene, propylene, vinylidene fluoride, acrylic acid, acrylic ester, styrene, acrylonitrile, maleic anhydride, vinyl chloride, and allyl chloride.

[0091] In some embodiments, the housing 100 includes a first sealing portion 140 and a second sealing portion 150, and the first sealing portion 140 and the second sealing portion 150 are arranged opposite to each other along the first direction Y. The first sealing portion 140 is bent toward the electrode assembly 200, and the second sealing portion 150 is bent toward the electrode assembly 200, so that the housing 100 occupies a smaller space, which is beneficial to improving the energy density of the battery cell 10.

[0092] In some embodiments, along the thickness direction X of the battery cell, the first sealing portion 140 does not extend beyond the first wall 110 , and the second sealing portion 150 does not extend beyond the first wall 110 , so that the first sealing portion 140 and the second sealing portion 150 have little effect on the overall thickness of the battery cell 10 , which is beneficial to improving the energy density of the battery cell 10 .

[0093] See also Figure 1 In some embodiments, the battery cell 10 includes a first electrical connector 230 and a second electrical connector 240, the first electrical connector 230 is connected to the positive electrode tab of the electrode assembly 200, the second electrical connector 240 is connected to the negative electrode tab of the electrode assembly 200, and extends out of the housing 100 along the second direction Y.

[0094] In some embodiments, the thickness direction X, the first direction Y, and the second direction Z of the battery cell are perpendicular to each other.

[0095] In some embodiments, the first electrical connector 230 and the positive electrode tab may be connected by welding, and the second electrical connector 240 and the negative electrode tab may be connected by welding.

[0096] In other embodiments, the first electrical connector 230 and the positive electrode tab may be integrally formed, and the second electrical connector 240 and the negative electrode tab may be integrally formed.

[0097] In some embodiments, the first electrical connector 230 and the second electrical connector 240 may be made of a material with good electrical conductivity, such as a metal material such as lead or copper.

[0098] In other embodiments, the first electrical connector 230 and the second electrical connector 240 may extend out of the housing 100 along the first direction Y.

[0099] Along the first direction Y, the first electrical connector 230 and the second electrical connector 240 are located on the same side of the electrode assembly 200 , and the first electrical connector 230 and the first sub-wall 111 are located on opposite sides of the electrode assembly 200 .

[0100] Refer to Table 1, in which H1 is the distance between the first sub-wall 111 and the second sub-wall 112 along the thickness direction X of the battery cell; θ1 is the angle between the first connecting wall 113 and the thickness direction X of the battery cell; D is the distance between one end of the second negative electrode tab 222 close to the first connecting wall 113 and the first end of the first sub-wall 111 close to the first connecting wall 113 along the first direction Y; S is the area of ​​the cavity 201 formed by the plane where the end faces of the first connecting wall 113 and the second negative electrode tab 222 close to the first connecting wall 113 are located, and the plane where the inner surface of the first sub-wall 111 is located.

[0101] When the punching depth of the packaging film is greater than 1.5 mm, a small angle can be formed directly between the first connecting wall and the thickness direction of the battery cell through the punching, so that the outer shell and the electrode assembly have better fit. When the punching depth of the packaging film is less than or equal to 1.5 mm, it is difficult to form a small angle between the first connecting wall and the thickness direction of the battery cell, resulting in poor fit between the outer shell and the electrode assembly. Therefore, Table 1 provided in this application only gives the comparative example with H1≤1.5 mm.

[0102] The measurement methods of the parameters in Table 1 are:

[0103] (1) H1 is the measured value of the distance from the inner surface of the second wall 120 to the inner surface of the first wall 110 along the thickness direction X of the battery cell.

[0104] (2) θ1 is the measured value of the angle between the plane where the first main body portion 1131 of the first connecting wall 131 is located and the direction from the second wall 120 toward the first wall 110 in the thickness direction X of the battery cell.

[0105] (3) D is the measured distance along the first direction Y between the plane where the end of the second negative electrode tab 222 close to the first connecting wall 113 is located and the first end of the first sub-wall 111 close to the first connecting wall 113 (i.e., the bending starting end of the first connecting wall 113).

[0106] (4) S is the area of ​​the cavity 201 formed by the first connecting wall 113, the plane where the end face of the second negative electrode plate 222 close to the first connecting wall 113 is located, and the plane where the inner surface of the first wall 110 is located. It is approximately a right triangle and can be calculated by the side length D of the cavity 201 along the first direction Y and the side length H1 of the cavity 201 along the thickness direction X of the battery cell, that is, S = 1 / 2*(H1*D).

[0107] Table 1 Measurement of the gap between the electrode assembly and the housing

[0108] H1 θ1 D S Comparative Example 1 1.5mm 50° 1.79mm <![CDATA[1.34mm 2 ]]> Example 1 1.5mm 45° 1.5mm <![CDATA[1.13mm 2 ]]> Example 2 1.5mm 30° 0.87mm <![CDATA[0.65mm 2 ]]> Example 3 1.5mm 20° 0.55mm <![CDATA[0.41mm 2 ]]> Example 4 1.5mm 15° 0.4mm <![CDATA[0.3mm 2 ]]> Comparative Example 2 1mm 50° 1.19mm <![CDATA[0.6mm 2 ]]> Example 5 1mm 45° 1mm <![CDATA[0.5mm 2 ]]> Example 6 1mm 30° 0.58mm <![CDATA[0.29mm 2 ]]> Example 7 1mm 20° 0.36mm <![CDATA[0.18mm 2 ]]> Example 8 1mm 15° 0.27mm <![CDATA[0.13mm 2 ]]> Comparative Example 3 0.5mm 50° 0.6mm <![CDATA[0.15mm 2 ]]> Example 9 0.5mm 45° 0.5mm <![CDATA[0.13mm 2 ]]> Example 10 0.5mm 30° 0.29mm <![CDATA[0.07mm 2 ]]> Embodiment 11 0.5mm 20° 0.18mm <![CDATA[0.05mm 2 ]]> Example 12 0.5mm 15° 0.13mm <![CDATA[0.03mm 2 ]]>

[0109] According to Table 1, the following conclusions can be drawn:

[0110] 1. Referring to Comparative Example 1 and Examples 1-4, Comparative Example 2 and Examples 5-8, Comparative Example 3 and Examples 9-12, when θ1 is greater than 45°, the spacing distance between the first connecting wall 113 and the second negative electrode plate 222 along the first direction Y is relatively large, which will result in poor fit between the outer shell 100 and the electrode assembly 200, and the electrode assembly 200 is prone to shaking in the outer shell 100, affecting the stability of the battery cell 10; and the area of ​​the cavity 201 is relatively large, which will cause waste of the internal space of the battery cell 10, affecting the energy density of the battery cell 10.

[0111] When θ1 is less than or equal to 45°, the spacing distance between the first connecting wall 113 and the second negative electrode plate 222 along the first direction Y is small, which will make the outer shell 100 and the electrode assembly 200 fit better, the electrode assembly 200 is not easy to shake in the outer shell 100, and the stability of the battery cell 10 is better; and the area of ​​the cavity 201 is small, which is conducive to improving the energy density of the battery cell 10.

[0112] 2. Referring to Examples 1-4, when the electrode assembly 200 is installed into the outer shell 100, a certain space needs to be provided between the outer shell 100 and the electrode assembly 200. Otherwise, it is easy to cause difficulty in installing the electrode assembly 200 and the outer shell 100, and it is easy to cause the outer shell 100 or the electrode assembly 200 to be squeezed and damaged. When D is greater than 0.4 mm, it is convenient for the electrode assembly 200 to be installed into the outer shell 100. Therefore, when 20°≤θ1≤45°, it is convenient for the electrode assembly 200 to be installed into the outer shell 100, and the outer shell 100 and the electrode assembly 200 to fit better. The electrode assembly 200 is not easy to shake in the outer shell 100, and the stability of the battery cell 10 is better. In addition, the area of ​​the cavity 201 is small, which is beneficial to improving the energy density of the battery cell 10.

[0113] An embodiment of the present application provides an electrical device, comprising a battery cell 10 according to any of the above solutions, and the battery cell 10 is used to provide electrical energy to the electrical device.

[0114] The electrical device may be any of the aforementioned devices or systems using the battery cell 10 .

[0115] See also Figure 7 , Figure 7 A schematic diagram of a process for preparing a battery cell provided in some embodiments of the present application.

[0116] The present embodiment provides a method for preparing a battery cell 10, comprising:

[0117] S11. Provide a battery cell 10, the battery cell 10 includes a shell 100 and an electrode assembly 200, and the electrode assembly 200 is accommodated in the shell 100; the shell 100 includes a first wall 110 and a second wall 120 arranged relatively along a thickness direction X of the battery cell, the first wall 110 includes a first sub-wall 111, a second sub-wall 112 and a first connecting wall 113, the second sub-wall 112 protrudes from the first sub-wall 111 in a direction away from the second wall 120, and the first connecting wall 113 connects the first sub-wall 111 and the second sub-wall 112; along the thickness direction X of the battery cell, the distance between the first sub-wall 111 and the second sub-wall 112 is H1, satisfying 0mm

[0118] S12, shaping the first connecting wall 113 of the battery cell 10 by pressing the block, so that the angle θ1 between the first connecting wall 113 and the thickness direction X of the battery cell satisfies 0°<θ1≤45°.

[0119] ​By accommodating the electrode assembly 200 in the housing 100, the housing 100 can protect the electrode assembly 200; by making the housing 100 include a first wall 110 and a second wall 120 that are relatively arranged along the thickness direction X of the battery core, the first wall 110 includes a first sub-wall 111, a second sub-wall 112 and a first connecting wall 113, along the direction away from the second wall 120, the second sub-wall 112 protrudes from the first sub-wall 111, and the first connecting wall 113 connects the first sub-wall 111 and the second sub-wall 112, so that a step structure is formed between the first sub-wall 111 and the second sub-wall 112, which can be used to accommodate other components when the battery cell 10 is assembled in the electrical equipment; by making the distance H1 between the first sub-wall 111 and the second sub-wall 112 along the thickness direction X of the battery cell satisfy 0mm

[0120] See also Figure 2 , Figure 8 and Fig. 9 , Figure 8 This is a schematic diagram of a partially enlarged structure of a battery cell before shaping provided in some embodiments of the present application. Fig. 9 A schematic diagram of the three-dimensional structure of a shaping device and a battery cell provided in some embodiments of the present application.

[0121] The present application provides a method for preparing a battery cell, comprising:

[0122] ​S21. Provide a packaging film, and punch a first portion of the packaging film to form a first wall 110, wherein the first wall 110 includes a first sub-wall 111, a second sub-wall 112, and a first connecting wall 113, wherein the second sub-wall 112 protrudes from the first sub-wall 111, and the first connecting wall 113 connects the first sub-wall 111 and the second sub-wall 112; along the thickness direction of the first portion, the distance between the first sub-wall 111 and the second sub-wall 112 is H1, satisfying 0mm

[0123] S22 , punching a second portion of the packaging film to form a second wall 120 .

[0124] S23, providing an electrode assembly 200, placing the electrode assembly 200 on a packaging film, and folding the first portion and the second portion of the packaging film in half, so that the first wall 110 and the second wall 120 are respectively located on both sides of the electrode assembly 200 along its thickness direction.

[0125] S24 , sealing and cutting the packaging film to form the outer shell 100 , and the outer shell 100 and the electrode assembly 200 constitute the battery cell 10 .

[0126] S25. During the exhaust or formation stage of the battery cell 10, the first connecting wall 113 of the battery cell 10 is shaped by the pressing block 320 so that an angle θ1 between the first connecting wall 113 and the thickness direction X of the battery cell satisfies 0°<θ1≤45°.

[0127] In some embodiments, after step S24, the following is formed: Figure 7 In the battery cell 10 shown, the first connecting wall 113 of the battery cell 10 is not formed, the fit between the housing 100 and the electrode assembly 200 is poor, and along the first direction Y, the spacing distance between the first connecting wall 113 and the second electrode assembly 220 is large.

[0128] In some embodiments, the shaping device includes a carrier 310 and a pressing block 320, the pressing block 320 is provided with a protrusion 321, the battery cell 10 can be placed on the carrier 310, and the pressing block 320 moves in a direction close to the carrier 310, so that the protrusion 321 acts on the first connecting wall 113, so that the first connecting wall 113 is attached to the electrode assembly 200 along the first direction Y, forming a battery cell 10. Figure 2 The battery cell 10 is shown.

[0129] 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.

[0130] ​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: It comprises a housing and an electrode assembly, wherein the electrode assembly is accommodated in the housing; The housing comprises a first wall and a second wall which are arranged opposite to each other along the thickness direction of the battery core, the first wall comprises a first sub-wall, a second sub-wall and a first connecting wall, the second sub-wall protrudes from the first sub-wall in a direction away from the second wall, and the first connecting wall connects the first sub-wall and the second sub-wall; Along the thickness direction of the battery core, the distance between the first sub-wall and the second sub-wall is H1, satisfying 0mm<H1≤1.5mm; An included angle between the first connecting wall and the thickness direction of the battery core is θ1, satisfying 0°<θ1≤45°.

2. The battery cell according to claim 1, characterized in that: 0mm<H1≤1mm, 20°≤θ1≤45°.

3. The battery cell according to claim 1, characterized in that: The electrode assembly comprises a first pole piece group and a second pole piece group, the first pole piece group and the second pole piece group are stacked, and the size of the first pole piece group along a first direction is greater than the size of the second pole piece group along the first direction; The first pole piece group is located between the first sub-wall and the second wall, and the second pole piece group is located between the first pole piece group and the second sub-wall; The first direction is perpendicular to the thickness direction of the battery cell.

4. The battery cell according to claim 3, characterized in that: The first sub-wall has a first end close to the first connecting wall, and the second electrode plate group includes a second positive electrode plate and a second negative electrode plate stacked together. Along the first direction, the distance between one end of the second negative electrode plate close to the first connecting wall and the first end is D, satisfying D≤1.5mm.

5. The battery cell according to claim 1, characterized in that: Along the thickness direction of the battery core, the distance between the first sub-wall and the second wall is T1, and the distance between the second sub-wall and the second wall is T2, satisfying T1<T2.

6. The battery cell according to claim 1, characterized in that: One end of the first connecting wall is connected to the first sub-wall through a first arc transition portion, and the other end of the first connecting wall is connected to the second sub-wall through a second arc transition portion.

7. The battery cell according to claim 1, characterized in that: The first wall further includes a third sub-wall and a second connecting wall, the third sub-wall is located on a side of the second sub-wall away from the first sub-wall, the second sub-wall protrudes from the third sub-wall in a direction away from the second wall, and the second connecting wall connects the second sub-wall and the third sub-wall; Along the thickness direction of the battery core, the distance between the second sub-wall and the third sub-wall is H2, satisfying 0mm<H2≤1.5mm; An included angle between the second connecting wall and the thickness direction of the battery core is θ2, satisfying 0°<θ2≤45°.

8. The battery cell according to any one of claims 1 to 7, characterized in that: An insulating layer is disposed between the first wall and the electrode assembly, and the insulating layer at least covers the inner surface of the first connecting wall.

9. An electrical device, characterized in that: The invention comprises a battery cell as claimed in any one of claims 1 to 8, wherein the battery cell is used to provide electrical energy.

10. A method for preparing a battery cell, characterized in that: include: A battery cell is provided, the battery cell comprising a shell and an electrode assembly, the electrode assembly being accommodated in the shell; the shell comprising a first wall and a second wall arranged opposite to each other along a thickness direction of the battery cell, the first wall comprising a first sub-wall, a second sub-wall and a first connecting wall, the second sub-wall protruding from the first sub-wall in a direction away from the second wall, the first connecting wall connecting the first sub-wall and the second sub-wall; along the thickness direction of the battery cell, a distance between the first sub-wall and the second sub-wall is H1, satisfying 0mm<H1≤1.5mm; The first connecting wall of the battery cell is shaped by a pressing block so that an angle θ1 between the first connecting wall and the thickness direction of the battery cell satisfies 0°<θ1≤45°.

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