Battery monomer, battery device and electric equipment

Abstract

The utility model discloses a battery monomer, a battery device and electric equipment. The battery monomer comprises a shell, an electrode assembly and an insulating film, the electrode assembly is arranged in the shell, the electrode assembly is of a winding structure, and the electrode assembly comprises two planes which are oppositely spaced and two arc surfaces which are oppositely spaced in the winding circumferential direction; the insulating film comprises at least two sub-film sections, and the two sub-film sections respectively cover the two cambered surfaces and extend to the two planes; the two sub-film sections are oppositely spaced on at least one plane to form an opening, the opening extends in the first direction, the first direction is parallel to the axis direction of the cambered surface, and the two planes are arranged in the second direction. According to the technical scheme, the possibility of breakage of the pole piece can be reduced.

Description

Technical Field

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

[0002] In related art, after continuous charge and discharge cycles, the electrode assembly in the battery cell will expand and contact the inner wall of the battery shell. At this time, the electrode pieces in the electrode assembly will be subjected to the combined effects of expansion force and friction, making them prone to breakage. Utility Model Content

[0003] The main purpose of this application is to provide a battery cell, aiming to reduce the possibility of electrode breakage.

[0004] To achieve the above-mentioned objectives, the battery cell proposed in the present application includes a shell, an electrode assembly and an insulating film; the electrode assembly is arranged in the shell, the electrode assembly is a winding structure, and includes two relatively spaced planes and two relatively spaced arc surfaces in the winding circumferential direction; the insulating film includes at least two sub-membrane segments, two of which are respectively covered on the two arc surfaces and extend to the two planes; the two sub-membrane segments are relatively spaced on at least one plane to be configured as an opening, the opening extends along a first direction, the first direction is parallel to the axial direction of the arc surface, and the two planes are arranged in a second direction.

[0005] The battery cell in the technical solution of the present application is coated with an insulating film around the winding circumference of the electrode assembly. The insulating film is configured to include at least two sub-film segments, which are respectively coated on two curved surfaces and extend to coat two flat surfaces. At the same time, the two sub-film segments are spaced relative to each other on at least one plane to form an opening. This allows the portion of the diaphragm in the electrode assembly corresponding to the opening to expand before the electrode assembly contacts the inner sidewall of the housing, allowing the electrode assembly to expand during cyclic charge and discharge operation. In this case, the two sub-film segments do not constrain the electrode assembly, allowing the electrode assembly to expand smoothly without wrinkling. When the electrode assembly expands to contact the inner sidewall of the housing, the two sub-film segments are subjected to the friction force exerted by the housing, which locks the size of the opening. At this time, the two sub-film segments can constrain and limit the electrode assembly, preventing the portion of the electrode assembly located at the junction of the flat surface and the curved surface from being subjected to the combined effects of expansion force and friction, thereby reducing the possibility of fracture of the electrode sheet in this area of ​​the electrode assembly.

[0006] In some embodiments, the two sub-film segments are integrally structured and spaced relative to each other on a plane to form an opening. Thus, the two sub-film segments can be continuously wound and bonded, achieving a single winding and bonding process to complete the insulating film coating on the electrode assembly, thereby facilitating the coating of the insulating film.

[0007] In some embodiments, there are two electrode assemblies, which are arranged side by side along the second direction; there are two insulating films, one for each electrode assembly, and the openings in the two insulating films are arranged back-to-back in the second direction. This allows for increased battery cell capacity while fully utilizing the two inner sidewalls of the housing corresponding to the planes in the motor assembly. After the electrode assembly expands to contact the inner sidewalls of the housing, friction forces are applied to the two sub-film segments of the insulating film to lock the two openings in place.

[0008] In some embodiments, the two sub-membrane segments are split structures and are spaced relative to each other on two planes to form two openings, and the two openings are arranged opposite to each other in the second direction.

[0009] Therefore, the amount of insulating film used can be reduced, thereby helping to reduce usage costs.

[0010] In some embodiments, the electrode assembly includes a first electrode sheet, a second electrode sheet, and a separator. The separator has a winding tail end, and at least one of the two sub-membrane segments is wrapped around the winding tail end. This allows the winding tail end to be restrained, eliminating the need for additional restraining structures, thereby simplifying the structural configuration of the battery cell.

[0011] In some embodiments, the electrode assembly has a first centerline that is parallel to the second direction; in a projection perpendicular to the first direction, the first centerline is located within the opening. This allows the opening to be located in the middle of the electrode assembly, allowing the two sub-membrane segments on either side of the opening to be evenly distributed, thereby providing uniform restraint and positioning of both sides of the electrode assembly in the third direction.

[0012] In some embodiments, one of the two sub-membrane segments has a first wall surface, and the other has a second wall surface. The first wall surface and the second wall surface are spaced relative to each other in a third direction to form an opening. The third direction is parallel to the arrangement direction of the two arcuate surfaces. In the third direction, the distance between the first wall surface and the first centerline is defined as D1, and the distance between the second wall surface and the first centerline is defined as D2, satisfying the relationship: 1 / 3 ≤ D1 / D2 ≤ 3. This prevents the opening from being too close to the ends of the electrode assembly in the third direction and allows it to be preferably located in the middle of the electrode assembly, thereby improving the uniformity of the distribution of the two sub-membrane segments located on either side of the opening.

[0013] In some embodiments, in the third direction, the width of the opening is defined as D3, and the relationship 5mm≤D3≤20mm is satisfied, and the third direction is parallel to the arrangement direction of the two arc surfaces. In this way, the formation of the opening and the subsequent restraining effect of the insulating film on the electrode assembly after expansion to contact the inner side wall of the shell can be better balanced.

[0014] In some embodiments, the thickness of the insulating film is defined as H, and the relationship 50μm≤H≤100μm is satisfied. In this way, the subsequent restraining effect of the insulating film on the electrode assembly after expansion to contact the inner side wall of the shell and the size of the space occupied in the shell can be better balanced.

[0015] In some embodiments, the tensile strength of the insulating film is defined as σ, and the relationship 4000Mpa≤σ≤7000Mpa is satisfied. In this way, the insulating film has a higher tensile strength, and can play a stable restraining role on the electrode assembly after expansion to contact the inner side wall of the shell.

[0016] In some embodiments, the tensile strength decay rate of the insulating film is defined as P, and the relationship 0

[0017] In some embodiments, the material of the insulating film is polyimide, polyether ether ketone, polyphenylene sulfide, polytetrafluoroethylene, or polyaryletherketone. In this way, the insulating film can have a lower tensile strength decay rate, so as to play a stable restraining role on the electrode assembly.

[0018] The application also proposes a battery device, which comprises a battery box and the battery monomer in any of the above embodiments, and the battery monomer is arranged in the battery box.

[0019] The application also proposes a power consumption device, which comprises the battery monomer in any of the above embodiments, or the battery device. BRIEF DESCRIPTION OF DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiment or prior art description. Obviously, the drawings in the following description are only some embodiments of the application, and those skilled in the art can also obtain other drawings according to the structures shown in these drawings without any creative labor.

[0021] Figure 1 It is a structural schematic diagram of an embodiment of the vehicle of the application;

[0022] Figure 2 It is an exploded structural schematic diagram of an embodiment of the battery device of the application;

[0023] Figure 3 This is a schematic diagram of the explosion structure of an embodiment of a battery cell of the present application;

[0024] Figure 4 for Figure 3 Schematic diagram of the battery cell in the state when the electrode assembly is not expanded;

[0025] Figure 5 for Figure 4 Schematic diagram of the state where the middle electrode assembly is expanded to contact the inner wall of the shell;

[0026] Figure 6 for Figure 4 A schematic diagram of a partial structure of a battery cell in FIG.

[0027] Figure 7 for Figure 6 Another schematic diagram of a partial structure of a battery cell in FIG.

[0028] Figure 8 This is a schematic structural diagram of another embodiment of a battery cell of the present application;

[0029] Figure 9 for Figure 6 is a structural schematic diagram of an electrode assembly;

[0030] Figure 10 This is a simulation diagram of a battery cell of the present application.

[0031] Description of Figure Numbers:

[0032] 1000, vehicle; 100, battery device; 10, battery box; 11, box body; 13, upper cover; 10a, accommodating cavity; 20, battery cell; 20A, battery pack; 21, shell; 211, shell body; 213, end cover assembly; 2131, electrode terminal; 23, electrode assembly; 231, first pole piece; 233, second pole piece; 235, diaphragm; 2351, winding tail end; 23a, first center line; 237, plane; 239, arc surface; 25, insulating film; 251, sub-membrane segment; 2511, first wall; 2513, second wall; 25a, opening; 25a1, second center line; 200, controller; 300, motor.

[0033] The realization of the objectives, functional features and advantages of this application will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0034] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0035] It should be noted that all directional indications in the embodiments of the present application (such as up, down, left, right, front, back, etc.) are only used to explain the relative position relationship, movement status, etc. between the various components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0036] In this application, unless otherwise specified or limited, the terms "connection" and "fixation" should be understood in a broad sense. For example, "fixation" can mean fixed connection, detachable connection, or integration; mechanical connection or electrical connection; direct connection or indirect connection through an intermediate medium; internal communication between two elements or interaction between two elements, unless otherwise specified. For those skilled in the art, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0037] In addition, the descriptions of "first", "second", etc. in this application are for descriptive purposes only and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of such features. In addition, the meaning of "and / or" appearing throughout the text is to include three parallel solutions. Taking "A and / or B as an example", it includes solution A, or solution B, or a solution in which both A and B are satisfied. In addition, the technical solutions between the various embodiments can be combined with each other, but this must be based on the ability of ordinary technicians in this field to implement. When the combination of technical solutions is mutually contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by this application.

[0038] Battery devices, that is, devices for storing electrical energy, are not only widely used in energy storage power systems such as hydropower, thermal power, wind power and solar power stations, but are also widely used in electric vehicles such as electric bicycles, electric motorcycles, electric cars, rail trains and other fields.

[0039] The battery device may include a battery case and battery cells disposed within the case. The battery case may include a case body and an upper cover that covers the case body, enclosing a cavity for accommodating the battery cells. The battery cell is the smallest unit of a battery and typically includes a case body and an electrode assembly. The case body may include a shell body and an end cap assembly. One end of the shell body may be open, and the electrode assembly may be disposed within the shell body. The end cap assembly may cover the open end of the shell body and may include an injection port for injecting electrolyte into the shell body. The electrode assembly is the component of the battery cell where the electrochemical reaction actually occurs and may include a positive electrode sheet, a negative electrode sheet, and a separator disposed therebetween. The positive electrode sheet, negative electrode sheet, and separator are wound together to form a flat body comprising two opposing flat surfaces and two opposing curved surfaces. The battery cell may be a secondary battery or a primary battery; it may also be a lithium-sulfur battery, a sodium-ion battery, or a magnesium-ion battery, but is not limited thereto. Furthermore, the battery cell may be flat, rectangular, or have other shapes. In addition, a plurality of battery cells may be provided in the battery box, and the plurality of battery cells may be connected in series, in parallel, or in a hybrid connection including series connection and parallel connection.

[0040] Furthermore, after continuous charge and discharge cycles, the electrode assembly within the battery cell expands and comes into contact with the inner wall of the housing. At this point, the electrode sheets within the electrode assembly are subject to both expansion forces at the junction of the corresponding flat and curved surfaces, as well as frictional forces exerted by the inner wall of the housing on the corresponding flat surface. The combined effects of these expansion and frictional forces can easily cause the outer electrode sheets within the electrode assembly to break at this location.

[0041] Therefore, based on the above considerations, in order to solve the problem in the related art that the outer ring of the electrode assembly is prone to fracture at the junction of the flat surface and the curved surface after the electrode assembly expands to contact the shell, the present application proposes a new type of battery cell. This new type of battery cell innovatively configures the insulating film covering the circumference of the electrode assembly to include at least two sub-film segments, each of which covers the two curved surfaces and extends to cover the flat surface. At the same time, the two sub-film segments are relatively spaced on at least one plane to form an opening extending along the axis of the curved surface. This allows the diaphragm in the electrode assembly through the corresponding opening to expand before the electrode assembly contacts the inner sidewall of the shell. The two film segments do not constrain the electrode assembly, allowing the electrode assembly to expand smoothly without wrinkling. After the electrode assembly expands to contact the inner wall of the shell, the shell can apply friction to the two membrane segments to lock the opening size, and then the electrode assembly can be restrained and limited by the two sub-membrane segments, so that the part of the electrode assembly located at the connection area between the plane and the arc surface will not be affected by the combined effect of expansion force and friction force, reducing the possibility of the electrode assembly's pole piece breaking at this location.

[0042] In addition, it should be noted that the battery cell provided in the present application can be directly applied to an electrical equipment to provide power for the electrical equipment. Of course, the battery device can also be applied, and then further applied to the electrical equipment to provide power for the electrical equipment. The electrical equipment can be, but is not limited to, a mobile phone, a tablet computer, a notebook computer, an electric toy, an electric tool, an electric car, an electric vehicle, a rail train, a ship, a spacecraft, etc. Further, the electric toy can include a fixed or mobile electric toy, such as a game console, an electric car toy, an electric ship toy, and an electric plane toy, etc. The spacecraft can include an airplane, a rocket, a space shuttle, and a spacecraft, etc.

[0043] The following embodiments are described by taking a vehicle as an example for convenience of description.

[0044] Figure 1 A structural schematic diagram of a vehicle 1000 provided in some embodiments of the present application is shown in FIG. 1. The vehicle 1000 can be a fuel automobile, a gas automobile, or a new energy automobile, which can be a pure electric automobile, a hybrid electric automobile, or a range extended automobile, etc. The vehicle 1000 is internally provided with a battery device 100, which can be arranged at the bottom, the head, or the tail of the vehicle 1000. The battery device 100 can be used for power supply of the vehicle 1000, for example, the battery device 100 can be used as an operating power source of the vehicle 1000. The vehicle 1000 can further include a controller 200 and a motor 300, and the controller 200 is used to control the battery device 100 to supply power to the motor 300, for example, to meet the working power demand of the vehicle 1000 during starting, navigation, and driving.

[0045] In some embodiments of the present application, the battery device 100 can not only be used as an operating power source of the vehicle 1000, but also be used as a driving power source of the vehicle 1000, to replace or partially replace fuel or natural gas to provide driving power for the vehicle 1000.

[0046] Figure 2 An exploded view of the battery device 100 provided in some embodiments of the present application is shown in FIG. 2. The battery device 100 includes a battery box 10 and a battery cell 20. The battery box 10 can be used to provide a containing space for the battery cell 20, and the battery box 10 can adopt various structures. In some embodiments, the battery box 10 can include a box body 11 and an upper cover 13 which are covered with each other to jointly define a receiving cavity 10a for containing the battery cell 20. The box body 11 and the upper cover 13 can be both hollow structures with one side open, and the open side of the upper cover 13 covers the open side of the box body 11. Of course, the upper cover 13 can also be a plate structure. In addition, the battery box 10 can have various shapes, such as a cylinder, a cuboid, etc.

[0047] The battery cell 20 is the smallest unit that constitutes the battery device 100. In the battery device 100, one battery cell 20 can be provided. Of course, the battery cell 20 can also be provided with at least two battery cells 20, and the at least two battery cells 20 can be connected in series or in parallel or in a mixed connection to form a battery pack 20A. The mixed connection means that there are both series and parallel connections among the plurality of battery cells 20. In addition, each battery cell 20 can be a secondary battery or a primary battery; it can also be a lithium-sulfur battery, a sodium-ion battery, or a magnesium-ion battery, but is not limited thereto. The battery cell 20 can be in the shape of a flat body, a cuboid, or other shapes. In addition, the battery device 100 can also include other structures, for example, the battery device 100 can also include a busbar component for realizing electrical connection between the plurality of battery cells 20.

[0048] Please refer to Figure 3 , Figure 4 and Figure 6 The battery cell 20 includes a shell 21, an electrode assembly 23, and an insulating film 25. The electrode assembly 23 is arranged in the shell 21, and the electrode assembly 23 is in a wound structure and includes two opposite flat surfaces 237 and two opposite arc surfaces 239 in the wound circumferential direction; the insulating film 25 includes at least two sub-film segments 251, two of which are respectively wrapped around the two arc surfaces 239 and both extend to the two flat surfaces 237; the two sub-film segments 251 are oppositely spaced apart at least on one flat surface 237 to form an opening 25a, and the opening 25a is arranged to extend in a first direction, and the first direction is parallel to the axis direction of the arc surface 239.

[0049] The shell 21 can be used to provide a housing space for the electrode assembly 23. The shell 21 can include a shell body 211 and an end cover assembly 213, one end of the shell body 211 can be arranged in an open manner, and the end cover assembly 213 can cover the opening of the shell body 211 to isolate the internal environment of the battery cell 20 from the external environment. In addition, the end cover assembly 213 can be provided with functional components such as electrode terminals 2131. The electrode terminals 2131 can be used to electrically connect with the electrode assembly 23 for outputting or inputting the electrical energy of the battery cell 20. In addition, the end cover assembly 213 can also be provided with a pressure relief mechanism for relieving the internal pressure when the internal pressure or temperature of the battery cell 20 reaches a threshold value, and a liquid injection hole for injecting electrolyte and the like.

[0050] The electrode assembly 23 may be the component within the battery cell 20 where the electrochemical reaction occurs. The electrode assembly 23 includes a first electrode sheet 231, a second electrode sheet 233, and a separator 235, which are wound to form a flat structure. Furthermore, this flat structure forms two flat surfaces 237 and two curved surfaces 239 along the circumference of the winding. When the battery device 100 is in normal installation and use, the first direction may be vertical, or the height direction of the battery cell 20. In this case, the two flat surfaces 237 may be spaced relative to each other in the second direction, and the two curved surfaces 239 may be spaced relative to each other in the third direction. The second direction may be horizontal, or the width direction of the battery cell 20, and the third direction may be another horizontal direction, or the length direction of the battery cell 20. Furthermore, one of the first electrode sheet 231 and the second electrode sheet 233 is a positive electrode sheet, and the other is a negative electrode sheet. A battery cell 20 may be provided with one or two electrode assemblies 23.

[0051] The insulating film 25 can be used to bond and coat the side circumferential surfaces of the electrode assembly 23 in the winding circumferential direction, that is, the flat surface 237 and the arc surface 239. Since the outermost circle of the electrode assembly 23 is usually the diaphragm 235, the insulating film 25 can be coated on the diaphragm 235 located at the outermost circle. In addition, the insulating film 25 can include only two sub-membrane segments 251, and distributed on both sides of the electrode assembly 23 in the third direction. At this time, the two sub-membrane segments 251 can be spaced apart and enclosed to form an opening 25a only on one plane 237, or of course, they can be spaced apart and enclosed to form an opening 25a on two planes 237. Moreover, the winding tail end 2351 in the diaphragm 235 can be coated by at least one of the two sub-membrane segments 251, so that the two sub-membrane segments 251 can play a bonding role on the winding tail end 2351 in the isolation membrane. Of course, the two sub-membrane segments 251 may not cover the winding tail end 2351 in the diaphragm 235, but other membrane segments may be further arranged in the opening 25a formed by the two sub-membrane segments 251, and the winding tail end 2351 in the diaphragm 235 may be covered by the membrane segments.

[0052] The battery cell 20 in the technical solution of the present application is coated with an insulating film 25 in the winding circumference of the electrode assembly 23, and the insulating film 25 is configured to include at least two sub-film segments 251, which are respectively coated on the two curved surfaces 239 and extend to coat the two planes 237. At the same time, the two sub-film segments 251 are relatively spaced on at least one plane 237 to form an opening 25a. In this way, before the electrode assembly 23 contacts the inner wall of the shell 21, Figure 4As shown, the portion of the diaphragm 235 in the electrode assembly 23 corresponding to the opening 25a can be extended so that the electrode assembly 23 can expand during the cyclic charge and discharge operation. At this time, the two sub-membrane segments 251 will not restrain the electrode assembly 23, so that the electrode assembly 23 can expand smoothly without wrinkling. Then, when the electrode assembly 23 expands to contact the inner wall of the shell 21, as shown in FIG. Figure 5 As shown, the two sub-membrane segments 251 are subjected to the frictional force exerted by the housing 21, which causes the opening 25a to be locked in place. At this point, the two sub-membrane segments 251 can restrain and limit the electrode assembly 23 in the third direction, so that the portion of the electrode assembly 23 at the junction of the flat surface 237 and the curved surface 239 is not affected by the combined effects of expansion force and friction, thereby reducing the possibility of fracture of the electrode piece of the electrode assembly 23 at this location.

[0053] Please refer to Figure 4 、 Figure 6 as well as Figure 7 In one embodiment of the present application, the two sub-membrane segments 251 are an integral structure and are spaced relative to each other on a plane 237 to form an opening 25 a.

[0054] The integral structure is formed into an inseparable whole. In this case, the insulating film 25 formed by the two sub-membrane segments 251 can be said to have a leading end and a trailing end. The leading end and the trailing end are located on the same plane 237 and are spaced relative to each other to form an opening 25a. Furthermore, the two sub-membrane segments 251 can be divided by the first centerline 23a of the electrode assembly 23 in the third direction.

[0055] In this embodiment, the two sub-film segments 251 are set as an integral structure, so that when the insulating film 25 is wound and bonded, the two sub-film segments 251 can be wound and bonded continuously, and the insulating film 25 can be wrapped on the electrode assembly 23 in one winding and bonding, which is conducive to improving the convenience of wrapping the insulating film 25. At the same time, the contact area between the insulating film 25 and the electrode assembly 23 can also be increased, which is conducive to improving the restraining and limiting effect of the insulating film 25 after the electrode assembly 23 expands to contact the inner wall of the shell 21. In addition, a structural foundation can be provided so that when two electrode assemblies 23 are set in the shell 21, the openings 25a of the insulating film 25 on each electrode assembly 23 can be arranged relative to the inner wall of the corresponding plane 237 in the shell 21.

[0056] Please refer to Figure 4 and Figure 5In one embodiment of the present application, there are two electrode assemblies 23, and the two electrode assemblies 23 are arranged side by side along the second direction; there are two insulating films 25, one insulating film 25 is provided in one electrode assembly 23, and the openings 25a in the two insulating films 25 are arranged back to back in the second direction.

[0057] In this embodiment, two electrode assemblies 23 are disposed within the housing 21 to increase the battery capacity of the battery cell 20. Furthermore, the openings 25a in the two insulating films 25 are disposed back to back, thereby fully utilizing the two inner sidewalls of the housing 21 corresponding to the plane 237. After the electrode assemblies 23 expand to contact the inner sidewalls of the housing 21, friction forces are applied to the two sub-film segments 251 in the insulating film 25, locking the two openings 25a in place.

[0058] Of course, this application is not limited to this, please refer to Figure 8 In one embodiment of the present application, the two sub-film segments 251 can be configured as separate structures and spaced relatively apart on two planes 237 to form two openings 25a. The two openings 25a are arranged opposite each other in the second direction. In this case, the amount of insulating film 25 used can be reduced, thereby helping to reduce the cost of use.

[0059] In one embodiment of the present application, at least one of the two sub-film segments 251 is wrapped around the winding tail end 2351 .

[0060] In this embodiment, the winding tail end 2351 in the diaphragm 235 is set to be covered and bonded by at least one of the two sub-membrane segments 251, so that the winding tail end 2351 can be limited, and there is no need to set an additional limiting structure for it, so as to simplify the structural setting of the battery cell 20.

[0061] Please refer to Figure 7 In one embodiment of the present application, the electrode assembly 23 has a first center line 23a, the first center line 23a is parallel to the second direction, and on a projection plane perpendicular to the first direction, the first center line 23a is located within the opening 25a.

[0062] The first center line 23a may be located at a middle position between the centers of the two arc surfaces 239. The first center line 23a is located in the opening 25a, that is, the first center line 23a passes through the opening 25a.

[0063] In this embodiment, the first center line 23a is set to pass through the opening 25a, so that the opening 25a can be located in the middle position of the electrode assembly 23, so that the two sub-membrane segments 251 located on both sides of the opening 25a can be distributed more evenly, so as to subsequently play a uniform restraining and limiting role on both sides of the electrode assembly 23 in the third direction.

[0064] Please refer toFigure 7 In one embodiment of the present application, one of the two sub-membrane segments 251 has a first wall 2511, and the other has a second wall 2513. The first wall 2511 and the second wall 2513 are relatively spaced apart in the third direction to form an opening 25a. In the third direction, the distance between the first wall 2511 and the first center line 23a is defined as D1, and the distance between the second wall 2513 and the first center line 23a is defined as D2, satisfying the relationship: 1 / 3≤D1 / D2≤3.

[0065] In this embodiment, the ratio of D1 to D2 is set to 1 / 3 to 3, so that the opening 25a is not too close to the ends of the electrode assembly 23 in the third direction, and can be preferably located in the middle of the electrode assembly 23, thereby improving the uniformity of the distribution of the two sub-membrane segments 251 located on both sides of the opening 25a. The ratio of D1 to D2 can be 1 / 3, 1 / 2, 1, 2, or 3, and can also be any value within the above ranges.

[0066] In one embodiment of the present application, the opening 25a may have a second center line 25a1, and on the projection plane perpendicular to the first direction, the second center line 25a1 may coincide with the first center line 23a to further improve the uniformity of the distribution of the two sub-membrane segments 251 located on both sides of the opening 25a.

[0067] Please refer to Figure 7 In one embodiment of the present application, in the third direction, the width of the opening 25a is defined as D3, satisfying the relationship: 5㎜≤D3≤20㎜.

[0068] In this embodiment, the width D3 of the opening 25a is set to 5 mm to 20 mm, so that the width of the opening 25a will not be too small, resulting in difficulty in forming due to precision issues when winding the insulating film 25. At the same time, the width of the opening 25a will not be too large, which will affect the size of the two sub-film segments 251 located on both sides of the opening 25a, thereby affecting the subsequent restraining and limiting effect of the electrode assembly 23 after it expands to contact the inner wall of the shell 21. Among them, the width D3 of the opening 25a can be 5 mm, 10 mm, 15 mm or 20 mm, and of course, it can also be any value within the above range.

[0069] In one embodiment of the present application, the thickness of the insulating film 25 is defined as H, which satisfies the relationship: 50 μm≤H≤100 μm.

[0070] In the embodiment, the thickness H of the insulation film 25 is set to 50-100 μm, so that the thickness of the insulation film 25 will not be too small to affect the restraining effect of the electrode assembly 23 after it expands to contact the inner side wall of the case 21, and the thickness of the insulation film 25 will not be too large to occupy too much space in the case 21. The thickness H of the insulation film 25 can be 50 μm, 55 μm, 60 μm, 65 μm, 70 μm, 75 μm, 80 μm, 85 μm, 90 μm, 95 μm or 100 μm, or any value within the range.

[0071] In addition, it should be noted that D1, D2, D3 and H are defined when the electrode assembly 23 is not expanded.

[0072] In an embodiment of the application, in order to improve the restraining effect of the insulation film 25 on the electrode assembly 23 after it expands to contact the inner side wall of the case 21, the tensile strength of the insulation film 25 is defined as σ, satisfying the relationship: 4000 Mpa≤σ≤7000 Mpa. At this time, the insulation film 25 has a high tensile strength, and can stably restrain the electrode assembly 23 after it expands to contact the inner side wall of the case 21. The tensile strength σ of the insulation film 25 can be 4000 Mpa, 5000 Mpa, 6000 Mpa or 7000 Mpa, or any value within the range.

[0073] In order to achieve the same effect, in an embodiment of the application, the tensile strength decay rate of the insulation film 25 is defined as P, satisfying the relationship: 0

[0074] In order to make the insulation film 25 have a low tensile strength decay rate, in an embodiment of the application, the material of the insulation film 25 can be polyimide, polyether ether ketone, polyphenylene sulfide, polytetrafluoroethylene or polyaryletherketone.

[0075] Please refer to Figure 6 In an embodiment of the application, the height of the insulation film 25 in the first direction is equal to the height of the electrode assembly 23 in the first direction, so as to increase the wrapping area of the electrode assembly 23.

[0076] Please refer to Figure 10In one embodiment of the present application, simulation experimental tests were conducted, including three embodiments. The first embodiment is a benchmark, that is, the test of the electrode assembly 23 in the related art; the second embodiment is a test in which an insulating film 25 with an H of 30 μm and a tensile strength σ of 4000 MPa is used to cover the electrode assembly 23, and an opening 25a is formed on a plane 237 of the electrode assembly 23; the third embodiment is a test in which an insulating film 25 with an H of 60 μm and a tensile strength σ of 4000 MPa is used to cover the electrode assembly 23, and an opening 25a is formed on a plane 237 of the electrode assembly 23.

[0077] This simulation demonstrates that the insulating film 25 coating method employed in this solution significantly reduces the elongation at break of the electrode. Furthermore, in this third embodiment, a simulation model based on a battery cell 20 of approximately 300Ah was used to simulate the risk of electrode cracking in the late stages of cycling, yielding an estimated benefit of greater than 2% SOH. Based on a 20-year battery cycle, the risk of long-term electrode cracking is estimated to be extended by 1.5 years. Furthermore, SOH represents the battery's state of health.

[0078] Please refer to Figures 3 to 7 In one embodiment of the present application, a battery cell 20 includes a housing 21, an electrode assembly 23, and an insulating film 25. The electrode assembly 23 is disposed within the housing 21 and has a wound structure. The electrode assembly 23 includes two opposing planar surfaces 237 and two opposing curved surfaces 239 circumferentially spaced apart. The insulating film 25 includes at least two sub-film segments 251, each of which wraps around the two curved surfaces 239 and extends to the two planar surfaces 237. The two sub-film segments 251 are spaced apart on at least one planar surface 237 to form an opening 25a. The opening 25a extends along a first direction parallel to the axis of the curved surface 239. The two sub-film segments 251 are integrally structured and spaced apart on the planar surface 237 to form an opening 25a. There are two electrode assemblies 23, and the two electrode assemblies 23 are arranged side by side along the second direction, and the second direction is parallel to the arrangement direction of the two planes 237; there are two insulating films 25, and one insulating film 25 is arranged in one electrode assembly 23, and the openings 25a in the two insulating films 25 are arranged back to back in the second direction.

[0079] The above description is only a preferred embodiment of the present application and does not limit the patent scope of the present application. All equivalent structural transformations made by using the contents of the present application description and drawings under the inventive concept of the present application, or direct / indirect application in other related technical fields are included in the patent protection scope of the present application.

Claims

1. A battery cell, characterized in that: include: case; an electrode assembly, the electrode assembly being disposed in the housing, the electrode assembly being a wound structure and comprising two relatively spaced flat surfaces and two relatively spaced arc surfaces in a circumferential direction of the winding; and An insulating film, the insulating film comprising at least two sub-film segments, wherein two of the sub-film segments are respectively covered on the two arc surfaces and extend to the two planes; The two sub-membrane segments are spaced relative to each other on at least one of the planes to form an opening, the opening extending along a first direction parallel to the axis of the arc surface, and the two planes are arranged in a second direction.

2. The battery cell according to claim 1, wherein: The two sub-membrane segments are an integral structure and are spaced relative to each other on a plane to form an opening.

3. The battery cell according to claim 2, wherein: There are two electrode assemblies, and the two electrode assemblies are arranged side by side along the second direction; There are two insulating films, one insulating film is provided on one electrode assembly, and the openings in the two insulating films are arranged back to back in the second direction.

4. The battery cell according to claim 1, wherein: The two sub-membrane segments are split structures and are spaced relative to each other on the two planes to form the two openings. The two openings are arranged relative to each other in the second direction.

5. The battery cell according to claim 1, wherein: The electrode assembly includes a first electrode plate, a second electrode plate, and a diaphragm. The diaphragm has a winding tail end, and at least one of the two sub-membrane segments is wrapped around the winding tail end.

6. The battery cell according to any one of claims 1 to 5, characterized in that: The electrode assembly has a first centerline, and the first centerline is parallel to the second direction; On a projection plane perpendicular to the first direction, the first center line is located within the opening.

7. The battery cell according to claim 6, wherein: One of the two sub-membrane segments has a first wall surface, and the other has a second wall surface, the first wall surface and the second wall surface are spaced apart from each other in a third direction to form the opening, and the third direction is parallel to the arrangement direction of the two arc surfaces; In the third direction, the distance between the first wall surface and the first center line is defined as D1, and the distance between the second wall surface and the first center line is defined as D2, satisfying the relationship: 1 / 3≤D1 / D2≤3.

8. The battery cell according to any one of claims 1 to 5, characterized in that: In the third direction, the width of the opening is defined as D3, satisfying the relationship: 5㎜≤D3≤20㎜, and the third direction is parallel to the arrangement direction of the two arc surfaces.

9. The battery cell according to any one of claims 1 to 5, characterized in that: The thickness of the insulating film is defined as H, which satisfies the relationship: 50 μm≤H≤100 μm.

10. The battery cell according to any one of claims 1 to 5, characterized in that: The tensile strength of the insulating film is defined as σ, which satisfies the relationship: 4000 MPa≤σ≤7000 MPa.

11. The battery cell according to any one of claims 1 to 5, characterized in that: The tensile strength attenuation rate of the insulating film is defined as P, which satisfies the relationship: 0<P≤0.

3.

12. The battery cell according to any one of claims 1 to 5, characterized in that: The insulating film is made of polyimide, polyetheretherketone, polyphenylene sulfide, polytetrafluoroethylene or polyaryletherketone.

13. A battery device, characterized in that: include: Battery box; and The battery cell according to any one of claims 1 to 12, wherein the battery cell is arranged in the battery box.

14. An electrical device, characterized in that: A battery cell according to any one of claims 1 to 12, or a battery device according to claim 13.

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