Battery cell and manufacturing method thereof, battery device and power-consuming device

Abstract

The present application relates to the field of battery technology, and specifically discloses a battery cell and a manufacturing method thereof, a battery device and an electrical device. The electrode assembly of the battery cell includes a diaphragm and a plurality of pole pieces. Two adjacent pole pieces with opposite polarities among the plurality of pole pieces are respectively constructed into a composite layer structure with a diaphragm. The diaphragm has a connected membrane body and an isolating portion. Both edges of the main body of the pole piece included in the composite layer structure are located between the membrane body and an isolating portion, or an edge of the main body with a pole ear protruding thereon is located between the membrane body and an isolating portion. When the temperature inside the battery cell of the present invention reaches the shrinkage temperature, even if the diaphragm shrinks due to heat, the isolating portion after shrinkage can still be located on the side of the main body facing away from the membrane body, so that the possibility of the edge between the membrane body and the isolating portion being exposed is greatly reduced, and the possibility of short-circuiting heat generation due to contact of pole pieces with opposite polarities is reduced, thereby improving the thermal stability of the battery cell, thereby reducing the safety hazards of the battery cell.

Description

Technical Field

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

[0002] Energy conservation and emission reduction are the key to the sustainable development of the automobile industry. Electric vehicles have become an important part of the sustainable development of the automobile industry due to their advantages in energy conservation and environmental protection. For electric vehicles, battery technology is an important factor in their development.

[0003] In actual use, the battery has a short circuit problem caused by thermal runaway, which will further cause the temperature inside the battery to rise sharply, posing a hidden danger to the safety of the battery. Specifically, the reason why thermal runaway causes short circuit is that the thermal runaway phenomenon is accompanied by the release of high-temperature and high-pressure gas, and the adjacent battery cells heat up accordingly, which in turn causes the internal diaphragm to shrink and deform due to heat, resulting in the isolation failure of the diaphragm and the direct contact of the pole pieces with opposite polarities, causing a short circuit. Summary of the invention

[0004] In view of the above problems, the present application provides a battery cell and a manufacturing method thereof, a battery device and an electrical device, which can reduce the possibility of diaphragm isolation failure and reduce the risk of short circuit caused by exposing the edge of the electrode.

[0005] The first aspect of the present application proposes a battery cell, comprising: a shell and an electrode assembly accommodated in the shell, the electrode assembly comprising a diaphragm and a plurality of pole pieces; the pole piece has a main body and a pole ear, the main body has two edges opposite to each other along its width direction, and the pole ear protrudes from the main body from one of the two edges; the diaphragm has a connected membrane body and an isolating portion, the membrane body has two side edges along the width direction of the pole piece, and the two side edges are respectively on the same side as the two edges; two adjacent pole pieces with opposite polarities among the plurality of pole pieces are respectively constructed into a composite layer structure with a diaphragm, and the diaphragm can isolate the two pole pieces; wherein the composite layer structure is configured so that at least one of the two side edges located on the pole ear side of the pole piece is connected to the isolating portion, and the main body of the pole piece is located between the membrane body and the isolating portion, and the composite layer structure is also configured so that the pole ear does not interfere with the diaphragm.

[0006] The battery cell of this embodiment is designed to include a connected membrane body and a separator by respectively constructing any two adjacent pole pieces of opposite polarity with a diaphragm. In addition, the composite layer structure is designed so that an edge of the main body with a pole ear protruding thereon is located between the membrane body and the separator to be covered, or the composite layer structure is designed so that both edges of the main body are located between the membrane body and the separator to be covered. With such a design, on the one hand, thanks to the fact that the membrane body and the separator are not coplanar, the tensions of the membrane body and the separator are not in the same plane. On the other hand, part of the separator is clamped by two adjacent layers of pole pieces. Therefore, even if the diaphragm shrinks due to heat, the shrunk separator can still be located on the side of the main body facing away from the membrane body, so that the possibility of the edge between the membrane body and the separator being exposed is greatly reduced. In this way, the possibility of short-circuiting heat generation due to contact between pole pieces of opposite polarity is reduced, and the thermal stability of the battery cell is improved, thereby reducing the safety hazards of the battery cell.

[0007] In some embodiments of the present application, the membrane body and the isolation part are an integral piece.

[0008] The isolation part is designed to be an integral part with the membrane body. In this example, the isolation part can be formed by folding when preparing the composite layer structure, which can save the connection process between the isolation part and the membrane body and simplify the production.

[0009] In some embodiments of the present application, the isolation portion is connected to a portion of one of the two side edges of the membrane body, and one of the two edges is on the same side as one of the two side edges and is partially covered.

[0010] On the basis that the isolation part and the membrane body are an integral part, the isolation part is designed to be connected to part of one of the two side edges of the membrane body. This allows the diaphragm to cover part of one of the two edges of the main body to reduce the possibility of edge exposure, and also facilitates the convenient staggered construction of the isolation part and the pole ear.

[0011] In some embodiments of the present application, when the isolating portion is connected to one of the two side edges located on the pole ear side of the pole piece, the isolating portion and the pole ear are staggered with each other along the length direction of the pole piece.

[0012] On the premise that the diaphragm can cover a portion of one of the two edges of the main body to reduce the exposure of the edge, the isolating portion and the electrode tab are staggered to prevent the isolating portion from interfering with the electrode tab.

[0013] In some embodiments of the present application, the isolation portion is completely connected to one of the two side edges of the membrane body, and one of the two edges is on the same side as one of the two side edges and is entirely covered.

[0014] On the basis that the isolation part and the membrane body are an integral part, the isolation part is designed to be completely connected to one of the two side edges of the membrane body, and most of one of the two edges of the main body is covered, and the possibility of exposure is further reduced.

[0015] In some embodiments of the present application, one of the two edges is provided with a plurality of tabs, and a plurality of avoidance holes are provided at the connection between the isolation portion and the membrane body, the number of the avoidance holes being the same as the number of tabs, and each tab passes through a corresponding avoidance hole. By providing the avoidance holes, the diaphragm and the tabs do not interfere with each other.

[0016] In some embodiments of the present application, the isolating part and the membrane body are separate parts, and the membrane body and the isolating part are fixedly connected. The isolating part and the membrane body are designed as separate parts, and the structure of the diaphragm is more flexible.

[0017] In some embodiments of the present application, the membrane body and the isolation part are connected by bonding, or the membrane body and the isolation part are connected by hot melting. Adhesive connection or hot melting connection is adopted, and the connection mode of the isolation part and the membrane body is simple and reliable.

[0018] In some embodiments of the present application, the diaphragm has an adhesive layer; the adhesive layer is located on the side of the diaphragm surface facing the pole piece, the adhesive layer is connected to the pole piece, and / or the adhesive layer is located on the side of the diaphragm surface facing away from the pole piece.

[0019] The diaphragm is provided with an adhesive layer, which can play a bonding role. Even if the diaphragm shrinks due to heat, the shrinkage of the diaphragm is limited by the adhesive relationship, so that the edge of the main body is exposed and the possibility of contact short circuit is small.

[0020] In some embodiments of the present application, along the width direction of the pole piece, the membrane body is wider than the main body, and both side edges extend beyond the two edges respectively.

[0021] By configuring in this way, the portion of each side that exceeds an edge on the same side is reserved for heat shrinkage, thereby reducing the risk of the edge of the diaphragm being exposed after heat shrinkage, resulting in contact short circuit.

[0022] In some embodiments of the present application, the distance between the two sides beyond the two edges is L, and L satisfies: 2mm≤L≤10mm. In this way, the value of L is moderate. On the one hand, L will not be too small, that is, a certain margin is reserved for shrinkage, so that the risk of the edge being exposed due to thermal shrinkage of the diaphragm is small. On the other hand, L will not be too large, so that more electrolyte can be accommodated in the shell, which is conducive to improving the energy density of the battery cell.

[0023] In some embodiments of the present application, one of the two side edges located on the tab side of the pole piece is bonded to the tab. By designing the diaphragm so that the portion of the side edge that exceeds the edge of the same side is bonded to the tab, and the portion of the side edge that exceeds the edge of the same side is fixed to the tab, even if the diaphragm shrinks, the edge of the main body leading out the tab is less likely to be exposed due to the connection relationship.

[0024] In some embodiments of the present application, the distance of the two side edges beyond the two edges is L, the width of the main body is h, and the dimension of the isolating part along the width direction of the pole piece is H, and H satisfies: L<H<L+0.5×h. On the one hand, H>L, so that at least part of one edge of the main body can be covered. On the other hand, H<L+0.5×h, when the diaphragm is provided with two isolating parts, this can ensure that the two isolating parts are spaced a certain distance apart.

[0025] In some embodiments of the present application, H satisfies: 2mm<H≤15mm. Under the premise that H satisfies: L<H<L+0.5×h, since H≤15 mm, H will not be too large, and the overlapping part of the membrane body and the isolation part along the width direction of the main body is small, which is conducive to reducing the difficulty of manufacturing the diaphragm.

[0026] In some embodiments of the present application, the total thickness D of the diaphragm is equal everywhere; the membrane body has a stacked part and a non-stacked part, the orthographic projection of the isolation part on the surface of the membrane body along the thickness direction coincides with the stacked part, the thickness of the non-stacked part is equal to D, and the sum of the thickness of the isolation part and the thickness of the stacked part is equal to D.

[0027] On the basis that the diaphragm can cover at least one side edge of the main body, thereby reducing the possibility of the edge of the main body being exposed, this embodiment designs the diaphragm to have an equal total thickness everywhere, thereby making it possible for the electrode assembly to enter the shell smoothly, thereby ensuring that the battery cells can be assembled smoothly.

[0028] In some embodiments of the present application, both side edges are connected with an isolating portion, the two isolating portions are located on the same side of the membrane body, and the two isolating portions are spaced apart along the width direction of the pole piece.

[0029] Compared with one of the two sides connected to the isolation part, this embodiment connects both sides to the isolation part, and both edges of the main body are covered. Moreover, since the two isolation parts are located on the side of the main body facing away from the membrane body, the possibility of both edges being exposed can be reduced.

[0030] The second aspect of the present application provides a battery device, comprising: any one of the battery cells provided in the first aspect of the present application.

[0031] The third aspect of the present application proposes an electrical device, comprising: any one of the battery devices proposed in the second aspect of the present application, the battery device being used to provide electrical energy.

[0032] A fourth aspect of the present application provides a method for manufacturing a battery cell, comprising:

[0033] Two pole pieces with opposite polarities are provided, the pole pieces have a main body and a pole ear, the main body has two opposite edges along its width direction, and the pole ear protrudes from the main body from one of the two edges;

[0034] Each pole piece and a diaphragm are combined to obtain a composite layer structure; wherein the diaphragm has a connected membrane body and a separation part, and the membrane body has two side edges along the width direction of the pole piece, and the two side edges are respectively on the same side as the two edges; the composite layer structure is configured so that at least one of the two side edges located on the pole ear side of the pole piece is connected to the separation part, and the main body of the pole piece is located between the membrane body and the separation part, and the composite layer structure is also configured so that the pole ear does not interfere with the diaphragm;

[0035] Winding the two composite layer structures around a winding axis to obtain an electrode assembly;

[0036] The electrode assembly is housed in a casing to obtain a battery cell.

[0037] A fifth aspect of the present application provides a method for manufacturing a battery cell, comprising:

[0038] A plurality of pole pieces are provided, each pole piece having a main body and a pole ear, wherein the main body has two edges facing each other along its width direction, and the pole ear protrudes from the main body from one of the two edges;

[0039] Each pole piece and a diaphragm are combined to obtain a composite layer structure; wherein the diaphragm has a connected membrane body and a separation part, and the membrane body has two side edges along the width direction of the pole piece, and the two side edges are respectively on the same side as the two edges; the composite layer structure is configured so that at least one of the two side edges located on the pole ear side of the pole piece is connected to the separation part, and the main body of the pole piece is located between the membrane body and the separation part, and the composite layer structure is also configured so that the pole ear does not interfere with the diaphragm;

[0040] Stacking a plurality of composite layer structures to form an electrode assembly, and making the polarities of two adjacent pole pieces of the electrode assembly opposite;

[0041] The electrode assembly is housed in a casing to obtain a battery cell.

[0042] In some embodiments of the present application, when the membrane body and the isolation part are an integral part, each pole piece and a diaphragm are compounded to obtain a composite layer structure, specifically including:

[0043] The sheet-like diaphragm is stacked on one side of the pole piece, and both ends of the sheet-like diaphragm along the width direction of the pole piece are respectively beyond the two edges of the pole piece;

[0044] At least one end of the sheet-like diaphragm is folded toward the other side of the pole piece to form an isolation portion, so as to obtain a composite layer structure.

[0045] In this way, when preparing the composite layer structure, there is no need to make crease marks, and the sheet-like diaphragm only needs to be folded along the edge of the main body to the other side of the pole piece, which can simplify the preparation process.

[0046] In some embodiments of the present application, when the isolation part and the membrane body are separate parts, each pole piece and a diaphragm are compounded to obtain a composite layer structure, specifically including:

[0047] A membrane body and a pole piece are provided, the membrane body is stacked on one side of the pole piece, and two sides of the membrane body are respectively beyond two edges of the pole piece;

[0048] An isolating portion is arranged on the other side of the pole piece and the isolating portion is bonded or hot-pressed to one of the two side edges located on the pole ear side of the pole piece to obtain a composite layer structure, or two isolating portions are arranged on the other side of the pole piece and the two isolating portions are bonded or hot-pressed to the two side edges to obtain a composite layer structure.

[0049] In some embodiments of the present application, two isolation parts are arranged on the other side of the pole piece and the two isolation parts are respectively bonded or hot-pressed and fused to the two side edges to obtain a composite layer structure, specifically including:

[0050] Provide a film layer, cut the film layer into two isolation parts, set the two isolation parts on the other side of the pole piece in turn, and bond or hot-press the two isolation parts to the two side edges; or provide a film layer, set the film layer on the other side of the pole piece, bond or hot-press the two ends of the film layer along the width direction of the pole piece to the two side edges respectively, and cut the film layer into two isolation parts.

[0051] In this way, the two isolation parts belong to the same film layer, and in the process of preparing the composite layer structure, the size of the film layer is larger, which is convenient for operation. Moreover, the shrinkage performance of the two isolation parts can be consistent.

[0052] In some embodiments of the present application, before providing a membrane body and a pole piece, the method for manufacturing a battery cell further includes:

[0053] Providing an initial film; wherein the thickness of the initial film is the same everywhere and is d1;

[0054] A coating is applied to a portion of the surface of the initial film, and the thickness of the coating is made uniform everywhere and equal to the thickness d2 of the isolation portion, so as to obtain a film body.

[0055] With this design, the total thickness D of the manufactured diaphragm is equal everywhere, so that the edge of the main body may be less exposed and the electrode assembly can be smoothly inserted into the shell, ensuring that the battery cell can be assembled smoothly.

[0056] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] Figure 1 A schematic diagram of the structure of a vehicle according to an embodiment of the present application is schematically shown;

[0058] Figure 2 The structure diagram of a battery device according to an embodiment of the present application is schematically shown;

[0059] Figure 3 for Figure 2 An exploded schematic diagram of a battery cell shown in FIG.

[0060] Figure 4 A schematic cross-sectional view of a wound electrode assembly according to an embodiment of the present application is shown schematically;

[0061] Figure 5 A schematic cross-sectional view of a laminated electrode assembly according to an embodiment of the present application is shown schematically;

[0062] Figure 6 A schematic cross-sectional view of a laminated electrode assembly according to another embodiment of the present application is shown schematically;

[0063] Figure 7 The schematic diagram of the structure of the diaphragm and the pole piece of the first embodiment of the present application is schematically shown;

[0064] Figure 8 The schematic diagram of the structure of the diaphragm and the pole piece of the second embodiment of the present application is schematically shown;

[0065] Fig. 9 for Figure 7 and Figure 8 A schematic cross-sectional view of the composite layer structure shown in ;

[0066] Fig.10 The schematic diagram of the structure of the diaphragm and the pole piece of the third embodiment of the present application is schematically shown;

[0067] Fig.11 for Fig.10 A schematic cross-sectional view of the composite layer structure shown in ;

[0068] Fig.12 The schematic diagram of the structure of the diaphragm and the pole piece of the fourth embodiment of the present application is schematically shown;

[0069] Fig.13 for Fig.12 A schematic cross-sectional view of the composite layer structure shown in ;

[0070] Fig.14 The schematic diagram of the structure of the diaphragm and the pole piece of the fifth embodiment of the present application is schematically shown;

[0071] Fig.15 for Fig.14 A schematic cross-sectional view of the composite layer structure shown in ;

[0072] Fig.16 A schematic diagram schematically shows a process diagram of a method for manufacturing an electrode assembly according to another embodiment of the present application.

[0073] Description of reference numerals:

[0074] 1000. Vehicles;

[0075] 100. Battery device;

[0076] 10. Battery cell assembly; 11. Battery cell;

[0077] 110, electrode assembly; 111, pole piece; 111A, cathode pole piece; 111B, anode pole piece; 112, main body; 113, pole ear; 114, diaphragm; 1141, membrane body; 1142, isolating part; 120, shell; 121, shell; 122, end cover; 130, membrane layer; 140, composite layer structure;

[0078] 20. Box; 21. First box; 22. Second box;

[0079] 200, controller;

[0080] 300. Motor. DETAILED DESCRIPTION

[0081] The following embodiments of the technical solution of the present application are described in detail in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present application, and are therefore only used as examples, and cannot be used to limit the scope of protection of the present application.

[0082] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field to which this application belongs; the terms used herein 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.

[0083] In the description of the embodiments of the present application, the technical terms "first", "second", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present application, the meaning of "multiple" is more than two, unless otherwise clearly and specifically defined.

[0084] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations 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. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0085] In the description of the embodiments of the present application, the term "and / or" is only a description of the association relationship of the associated objects, indicating that there may be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0086] In the description of the embodiments of the present application, the term "multiple" refers to more than two (including two). Similarly, "multiple groups" refers to more than two groups (including two groups), and "multiple pieces" refers to more than two pieces (including two pieces).

[0087] In the description of the embodiments of the present application, the technical terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, which are only for the convenience of describing the embodiments of the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the embodiments of the present application.

[0088] In the description of the embodiments of the present application, unless otherwise clearly specified and limited, technical terms such as "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the internal connection of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0089] Most of the safety issues of batteries in actual applications are caused by thermal runaway. One of the safety issues is that thermal runaway batteries will produce high-temperature gas, and the heat will be transferred to adjacent battery cells, causing the adjacent battery cells to heat up rapidly. When the temperature inside the battery cells reaches the shrinkage temperature, the diaphragm shrinks, and the size of the diaphragm is reduced, causing the pole pieces with opposite polarities to contact and short-circuit.

[0090] When the electrode assembly of the battery cell is a winding structure, the anode electrode sheet, the separator, and the cathode electrode sheet are wound along the length direction, and the winding start end of the separator usually exceeds the winding end of the electrode sheet, and the winding end usually exceeds the terminal end of the electrode sheet. In addition, since the anode electrode sheet, the separator, and the cathode electrode sheet are all wound to form multiple circles, and each circle of the separator is sandwiched between two adjacent circles of electrode sheets with opposite polarities, the shrinkage creep of each circle of the separator along the winding direction is limited, so the shrinkage rate of the length of the separator is small.

[0091] When the electrode assembly of the battery cell is a laminated structure, the diaphragm is usually a continuous strip structure, and the diaphragm is folded back and forth in a Z-shape, so that the Z-shaped diaphragm separates two adjacent pole pieces. For similar reasons, each layer of the continuous strip diaphragm is sandwiched between two adjacent pole pieces, and the shrinkage creep of the diaphragm along the length direction is limited, so the shrinkage rate of the diaphragm length is small.

[0092] In general, when the temperature inside the battery cell reaches the shrinkage temperature, the diaphragm shrinks severely in the width direction, so that the diaphragm's isolation effect on the edge of the electrode along its own width direction fails, resulting in the edges of two adjacent electrode pieces with opposite polarities contacting and short-circuiting.

[0093] In the present application, two adjacent pole pieces with opposite polarities are respectively constructed with a diaphragm to form a composite layer structure, and the diaphragm has a connected membrane body and an isolating portion. The composite layer structure is designed so that both edges of the main body of the pole piece are located between the membrane body and an isolating portion, so that both edges are covered, or the composite layer structure is designed so that the edge of the main body of the pole piece with a pole ear protruding therefrom is located between the membrane body and an isolating portion.

[0094] The battery involved in the embodiment of the present application can be used in, but not limited to, electrical devices such as vehicles, ships or aircraft. A power supply system comprising the battery cells, batteries, etc. involved in the present application can be used to form the electrical device.

[0095] In the embodiments of the present application, the electric device using the battery as the power source may be, but is not limited to, a mobile phone, a tablet, a laptop computer, an electric toy, an electric tool, a battery car, an electric car, a ship, a spacecraft, etc. Among them, the electric toy may include a fixed or mobile electric toy, for example, a game console, an electric car toy, an electric ship toy, an electric airplane toy, etc., and the spacecraft may include an airplane, a rocket, a space shuttle, a spacecraft, etc.

[0096] It should be understood that the technical solutions described in the embodiments of the present application are not limited to the batteries and electrical devices described above, but can also be applied to all batteries including a box and electrical devices using batteries. However, for the sake of simplicity, the following embodiments are explained using electric vehicles as examples.

[0097] Please refer to Figure 1 , Figure 1A schematic diagram of the structure of a vehicle 1000 provided for some embodiments of the present application. The vehicle 1000 may be a fuel vehicle, a gas vehicle or a new energy vehicle, and the new energy vehicle may be a pure electric vehicle, a hybrid vehicle or an extended-range vehicle, etc. A battery device 100 is provided inside the vehicle 1000, and the battery device 100 may be provided at the bottom, head or tail of the vehicle 1000. The battery device 100 may be used to power the vehicle 1000, for example, the battery device 100 may be used as an operating power source for the vehicle 1000. The vehicle 1000 may also include a controller 200 and a motor 300, and the controller 200 is used to control the battery device 100 to power the motor 300, for example, for starting, navigating and driving the vehicle 1000.

[0098] In some embodiments of the present application, the battery device 100 can not only serve as an operating power source for the vehicle 1000, but also serve as a driving power source for the vehicle 1000, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000.

[0099] Figure 2 FIG. 1 is a schematic diagram showing the structure of a battery device 100 according to an embodiment of the present application. Figure 2 As shown, the battery apparatus 100 (Battery Apparatus) mentioned in the embodiment of the present application may include one or more battery cell assemblies 10 for providing voltage and capacity. The battery cell assembly 10 (Battery Cell Assembly) may include a plurality of battery cells 11, and the plurality of battery cells 11 are connected in series, in parallel or in mixed connection through a busbar component.

[0100] In some embodiments, a battery cell assembly 10 (Battery Cell Assembly) is generally formed by arranging a plurality of battery cells 11 .

[0101] As an example, the battery cell assembly 10 may be a battery module (Battery Module), and the battery module is formed by arranging and fixing a plurality of battery cells 11 to form an independent module. As an example, the battery module may be formed by bundling a plurality of battery cells 11 by a cable tie.

[0102] In some embodiments, Figure 2As shown, the battery device 100 may be a battery pack, which includes a box 20 and one or more battery cell assemblies 10, and the battery cell assemblies 10 are contained in the box 20. The box 20 may be a simple three-dimensional structure such as a single cuboid, cylinder, or sphere, or a complex three-dimensional structure composed of simple three-dimensional structures such as cuboids, cylinders, or spheres. The material of the box 20 may be an alloy material such as aluminum alloy, iron alloy, or a polymer material such as polycarbonate, polyisocyanurate foam plastic, or a composite material such as glass fiber and epoxy resin.

[0103] As an example, the battery cell assembly 10 may be a battery module, and the battery cell assembly 10 may be accommodated in the box body 20 by fixing the battery module in the box body 20 .

[0104] As an example, the battery cell assembly 10 may also be accommodated in the case 20 by directly fixing the plurality of battery cells 11 to the case 20 .

[0105] As an example, the box 20 may include a first box 21 and a second box 22. The first box 21 and the second box 22 are buckled together to form a closed space inside the box 20 to accommodate the battery cell assembly 10. The closed space here means covering or closing, which may be unsealed or sealed to prevent liquid or other foreign matter from affecting the charging or discharging of the battery cell 11. The first box 21 may be a top cover or a bottom plate.

[0106] As an example, the box body 20 may include a top cover, a frame, and a bottom plate. The top cover and the bottom plate are respectively connected to the frame, so that a closed space is formed inside the box body 20 to accommodate the battery cell assembly 10.

[0107] In some embodiments, the box 20 can be used as a part of the chassis structure of the vehicle. For example, part of the box 20 can become at least a part of the floor of the vehicle, or part of the box 20 can become at least a part of the cross beam and longitudinal beam of the vehicle.

[0108] The battery cell 11 provided in the embodiment of the present application may be a secondary battery. A secondary battery refers to a battery cell 11 that can be continuously used by activating active materials by charging after the battery cell 11 is discharged.

[0109] The battery cell 11 may be a lithium ion battery, a sodium ion battery, a sodium lithium ion battery, a lithium metal battery, a sodium metal battery, a lithium sulfur battery, a magnesium ion battery, a nickel metal hydride battery, a nickel cadmium battery, a lead storage battery, etc., and the embodiments of the present application do not limit this. As an example, the battery cell 11 may be a cylindrical battery cell, a prismatic battery cell, or a battery cell 11 of other shapes, and the prismatic battery cell includes a square shell battery cell, a blade-shaped battery cell, and a multi-prismatic battery cell, and the multi-prismatic battery cell is, for example, a hexagonal battery cell, etc., and the present application has no special restrictions.

[0110] like Figure 3 As shown, the battery cell 11 provided in the embodiment of the present application includes a housing 120, an electrode assembly 110 and an electrolyte. The electrode assembly 110 is a component where an electrochemical reaction occurs in the battery cell 11. The electrode assembly 110 and the electrolyte are contained in the housing 120. As an example, the electrolyte may be liquid, gel or solid.

[0111] As an example, the housing 120 may be a steel shell, an aluminum shell, a plastic shell (such as polypropylene), a composite metal shell (such as a copper-aluminum composite shell) or an aluminum-plastic film. In some embodiments, the housing 120 may be a sealed structure or a non-sealed structure. As an example, when the housing 120 is a non-sealed structure, the housing 120 plays a role in protecting the electrode assembly 110, and a sealed bag is also included between the housing 120 and the electrode assembly 110, and the sealed bag is used to encapsulate the electrode assembly 110 and the electrolyte. Specifically, the sealed bag may be a bag-shaped insulating member or an aluminum-plastic film. When the housing 120 is a sealed structure, it is used to encapsulate components such as the electrode assembly 110 and the electrolyte.

[0112] In some embodiments, Figure 3 As shown, the housing 120 may include an end cap 122 and a shell 121. The shell 121 is provided with an opening, and the electrode assembly 110 is loaded into the shell 121 through the opening, and the end cap 122 is covered on the opening. The shell 121 may be provided with one or more openings. One or more end caps 122 may also be provided.

[0113] The specific structure of the electrode assembly 110 is described in detail below with reference to the accompanying drawings.

[0114] In some embodiments of the present application, Figure 4 and Figure 5 As shown, the electrode assembly 110 includes a plurality of pole pieces 111 and a separator 114. The electrode assembly 110 may be a winding structure or a laminated structure, which is not specifically limited in this embodiment.

[0115] Among them, the pole piece 111 includes a current collector and an active material disposed on at least one surface of the current collector. As an example, the current collector has two surfaces opposite to each other in its own thickness direction, and the active material is disposed on any one or both of the two opposite surfaces of the current collector. The current collector not coated with the active material material protrudes from the current collector coated with the active material material, the current collector not coated with the active material material serves as the pole ear 113, and the current collector coated with the active material material serves as the main body 112. In general, the pole piece 111 includes a main body 112 and a pole ear 113, the main body 112 has two edges along the width direction of the pole piece 111, the pole ear 113 protrudes from one of the two edges from the main body 112 and extends along the width direction of the pole piece 111, and the pole piece 111 has opposite pole ear sides and non-pole ear sides along its width direction. For clear description, the two edges are respectively referred to as the first edge and the second edge. In the various figures of the present application, the X-axis and the Y-axis represent the width direction and the length direction of the pole piece 111, respectively. It should be noted that when the electrode assembly 110 is accommodated in the housing 120 , the extension direction of the electrode tab 113 is parallel to the height direction of the housing 120 , that is, the electrode tab 113 faces the bottom wall or the top wall of the housing 120 .

[0116] As an example, the pole piece 111 may be provided with one or more pole ears 113 , and the plurality of pole ears 113 are distributed at intervals along the length direction of the pole piece 111 .

[0117] Some of the multiple pole pieces 111 are cathode pole pieces 111A, and the rest are anode pole pieces 111B. The battery cell 11 mainly relies on the movement of metal ions between the cathode pole piece 111A and the anode pole piece 111B to work. Taking a lithium-ion battery as an example, the material of the current collector of the cathode pole piece 111A can be aluminum, and the active material material can be lithium cobalt oxide, lithium iron phosphate, ternary lithium or lithium manganese oxide. The material of the current collector of the anode pole piece 111B can be copper, and the active material material can be carbon or silicon. In other words, the electrode assembly 110 includes at least one cathode pole piece 111A and at least one anode pole piece 111B.

[0118] Please continue to refer to Figure 4 and Figure 5 , two adjacent pole pieces 111 with opposite polarities among the plurality of pole pieces 111 are respectively configured with a separator 114 to form a composite layer structure 140, so that any two adjacent pole pieces 111 with opposite polarities are separated by the separator 114. In other words, the adjacent cathode pole piece 111A and the adjacent anode pole piece 111B are respectively configured with a separator 114 to form a composite layer structure 140.

[0119] It is understandable that the number of composite layer structures 140 is related to the number of separators 114, and the number of separators 114 is related to the number and arrangement of cathode pole pieces 111A and anode pole pieces 111B of the electrode assembly 110, as well as the manufacturing method of the electrode assembly 110. For ease of understanding, the cathode pole pieces 111A and anode pole pieces 111B are alternately arranged as an example for description herein.

[0120] When the electrode assembly 110 is a wound structure, Figure 3 , Figure 4 As shown, the electrode assembly 110 may specifically include two pole pieces 111 and two separators 114, and the cathode pole piece 111A and the anode pole piece 111B are respectively configured with a separator 114 to form a composite layer structure 140. That is, in this example, the electrode assembly 110 has two composite layer structures 140, and the electrode assembly 110 is formed by winding the two stacked composite layer structures 140 around a winding axis, and the extension direction of the winding axis is parallel to the width direction of the pole piece 111.

[0121] When the electrode assembly 110 is a laminated structure, please combine Figure 5 and Figure 6 The electrode assembly 110 may specifically include K pole pieces 111 and K diaphragms 114. Each pole piece 111 and a diaphragm 114 are configured to form a composite layer structure 140. In this example, the electrode assembly 110 is formed by stacking K composite layer structures 140 along a stacking direction, where K is a positive integer and K≥2.

[0122] Regardless of whether the electrode assembly 110 is a winding structure or a stacked structure, the protruding directions of the pole ears 113 of all anode pole sheets 111B are the same, and the pole ears 113 of multiple anode pole sheets 111B can be stacked together so that a large current can be passed without melting. Similarly, the protruding directions of the pole ears 113 of all cathode pole sheets 111A are the same, and the pole ears 113 of multiple cathode pole sheets 111A can be stacked together so that a large current can be passed without melting. Among them, the pole ears 113 of the anode pole sheet 111B and the pole ears 113 of the cathode pole sheet 111A can be located on the same side of the electrode assembly 110, that is, the pole ears 113 with opposite polarities are led out from the same side of the electrode assembly 110. Alternatively, the pole ears 113 of the anode pole sheet 111B and the pole ears 113 of the cathode pole sheet 111A can be located on different sides of the electrode assembly 110, that is, the pole ears 113 with opposite polarities are led out from both sides of the electrode assembly 110.

[0123] Please refer to Figures 4 to 15, the diaphragm 114 includes a connected membrane body 1141 and a separation part 1142, and the membrane body 1141 has two side edges along the width direction of the pole piece 111, and the two side edges are respectively on the same side as the two edges of the main body 112. For the sake of clear description, the two side edges are respectively referred to as the first side edge and the second side edge, wherein the first side edge and the first edge are located on the same side, and the second side edge and the second edge are located on the other side. The above-mentioned composite layer structure 140 is configured such that at least one of the two side edges located on the pole ear side of the pole piece 111 is connected to the separation part 1142. In addition, the main body 112 of the pole piece 111 of the composite layer structure 140 is located between the membrane body 1141 and the separation part 1142. The above-mentioned composite layer structure 140 is also configured such that the pole ear 113 does not interfere with the diaphragm 114. Each composite layer structure 140 in the electrode assembly 110 can be implemented in any of the following ways: one of the two edges of the main body 112 protruding with the pole ear 113 is covered and both edges are covered.

[0124] As an example, see Figures 7 to 9 ,as well as Figure 12 to Figure 13 , the diaphragm 114 may include an isolating portion 1142, the isolating portion 1142 and the membrane body 1141 are respectively located on both sides of the main body 112 along the thickness direction of the pole piece 111, and the isolating portion 1142 is connected to one of the two sides facing the pole ear 113. As one possibility, the first edge of the main body 112 is provided with a pole ear 113, the first side edge and the first edge are on the same side, the first side edge is connected to the isolating portion 1142, the first edge is covered, and the second side edge extends to the outside of the second edge of the main body 112. As another possibility, the second edge of the main body 112 is provided with a pole ear 113, the second side edge is connected to the isolating portion 1142, the second edge is covered, and the first side edge extends to the outside of the first edge of the main body 112. In this example, the composite layer structure 140 has an isolation portion 1142 , one of the two side edges facing the pole ear 113 is connected to the isolation portion 1142 to jointly protrude an edge of the pole ear 113 , and the other of the two side edges exceeds the other edge of the main body 112 that is not protruded.

[0125] During operation of the battery cell 11 using the composite layer structure 140, when the internal temperature reaches the shrinkage temperature due to thermal runaway, overcharging, etc., the total volume of the diaphragm 114 tends to decrease, so that the two sides of the membrane body 1141 have a tendency to shrink toward the middle of the membrane body 1141, and the isolation part 1142 has a tendency to shrink toward the side connected thereto. Since the isolation part 1142 and the membrane body 1141 each have a certain tension, and the isolation part 1142 located on both sides of the main body 112 and the membrane body 1141 are not in the same plane, the tension of the isolation part 1142 and the membrane body 1141 are not coplanar. In this way, even if the diaphragm 114 shrinks due to heat, the shrunk isolation part 1142 is still not coplanar with the membrane body 1141, but remains on the side of the main body 112 facing away from the membrane body 1141, so that the edge of the main body 112 with the pole ear 113 protruding therefrom can still be covered, and the possibility of the edge of the main body 112 with the pole ear 113 protruding therefrom being exposed is reduced. Since the other of the two side edges extends beyond the other of the two edges of the main body 112, compared with the method in which the other of the two side edges is flush with the other of the two edges, under the condition of the same parameters such as the shrinkage amount, this can at least reduce the possibility of the other edge of the main body 112 without the pole ear 113 protruding therefrom being exposed to a certain extent.

[0126] As an example, see Fig.10 and Fig.11 ,as well as Fig.14 and Fig.15 , the diaphragm 114 may include two isolating portions 1142 located on the same side of the membrane body 1141, and the two side edges are connected to the two isolating portions 1142 in a one-to-one correspondence. In this example, the composite layer structure 140 is provided with two isolating portions 1142, and the two isolating portions 1142 are both located on the side of the main body 112 facing away from the membrane body 1141, and both edges of the main body 112 of the composite layer structure 140 are covered. In addition, the two isolating portions 1142 are arranged at intervals along the width direction of the pole piece 111, that is, there is a certain distance between the ends of the two isolating portions 1142 facing each other, so that there is a part of the surface of the main body 112 facing the isolating portion 1142 that is not covered by the diaphragm 114.

[0127] During the operation of the battery cell 11 using the composite layer structure 140, when the internal temperature reaches the shrinkage temperature due to thermal runaway, overcharging, etc., the total volume of the diaphragm 114 tends to decrease, so that the two isolation parts 1142 have a tendency to shrink toward the side connected to them. Since the isolation part 1142 and the membrane body 1141 each have a certain tension, and the isolation parts 1142 and the membrane body 1141 located on both sides of the main body 112 are not in the same plane, the tension of the isolation part 1142 and the membrane body 1141 is not coplanar. In this way, even if the diaphragm 114 shrinks due to heat, the two edges of the main body 112 can be covered, and the possibility of the two edges being exposed is reduced.

[0128] It should also be pointed out that in the example where the electrode assembly 110 is a wound structure, the diaphragm 114 is also wound into multiple turns. When the isolation portion 1142 of the composite layer structure 140 is closer to the inner side of the electrode assembly 110 than the membrane body 1141, except for the innermost circle of diaphragm 114, the isolation portions 1142 of the remaining circles of diaphragms 114 are clamped between two adjacent circles of pole pieces 111. When the internal temperature of the battery cell 11 reaches the shrinkage temperature, the isolation portions 1142 of the remaining circles of diaphragms 114 are clamped and are difficult to escape from between the two adjacent circles of pole pieces 111, so that the corresponding edges on the main body 112 can be reliably covered. When the membrane body 1141 of the composite layer structure 140 is closer to the inner side of the electrode assembly 110 than the isolating portion 1142, except for the outermost circle of diaphragm 114, the isolating portions 1142 of the remaining circles of diaphragms 114 are clamped between two adjacent circles of pole pieces 111. When the internal temperature of the battery cell 11 reaches the shrinkage temperature, the isolating portions 1142 of the remaining circles of diaphragms 114 are clamped and are difficult to escape from between the two adjacent circles of pole pieces 111, so that the corresponding edges on the main body 112 can be reliably covered.

[0129] In the example where the electrode assembly 110 is a laminated structure, along the stacking direction, the isolation portion 1142 of the composite layer structure 140 located in the middle is stacked between two adjacent layers of pole pieces 111 and is difficult to escape from between the two adjacent layers of pole pieces 111, so that the corresponding edge on the main body 112 can be reliably covered.

[0130] Compared with the technical solution in which only one side is connected with the isolation part 1142, when both sides are connected with the isolation part 1142, the two edges of the main body 112 are covered, and because the two isolation parts 1142 are located on the side of the main body 112 facing away from the membrane body 1141, the possibility of exposure of the two edges can be reduced.

[0131] In summary of the above description, the battery cell 11 of this embodiment is constructed into a composite layer structure 140 by respectively connecting any two adjacent pole pieces 111 with opposite polarities with a separator 114, and the separator 114 is designed to include a connected membrane body 1141 and a separator 1142. In addition, the composite layer structure 140 is designed so that at least one of the two sides of the membrane body 1141 located on the pole ear side of the pole piece 111 is connected to the separator 1142, so that at least one of the two edges of the main body 112 where the pole ear 113 protrudes is located between the membrane body 1141 and the separator 1142 to be covered. With such a design, on the one hand, thanks to the fact that the membrane body 1141 and the isolation portion 1142 are not coplanar, the tensions of the membrane body 1141 and the isolation portion 1142 are not in the same plane; on the other hand, part of the isolation portion 1142 is clamped by the two adjacent layers of the pole pieces 111. Therefore, even if the diaphragm 114 shrinks due to heat, the shrunk isolation portion 1142 can still be located on the side of the main body 112 facing away from the membrane body 1141, thereby greatly reducing the possibility of exposure of the edge between the membrane body 1141 and the isolation portion 1142.

[0132] In this way, this embodiment reduces the possibility of isolation failure of the diaphragm 114 due to thermal shrinkage, reduces the risk of the two edges of the main body 112 being exposed due to thermal shrinkage of the diaphragm 114, reduces the possibility of short-circuiting and generating heat due to contact of pole pieces 111 with opposite polarities, improves the thermal stability of the battery cell 11, and thus reduces the safety hazards of the battery cell 11.

[0133] In some embodiments, the length of the diaphragm 114 of the composite layer structure 140 may be equal to the length of the main body 112, and the two ends of the main body 112 along its own length direction are respectively flush with the two ends of the diaphragm 114. Alternatively, the length of the diaphragm 114 of the composite layer structure 140 may also be greater than the length of the main body 112, and the two ends of the diaphragm 114 respectively exceed the two ends of the main body 112 along its own length direction. In this way, even if the length of the diaphragm 114 is reduced due to heat shrinkage, at least to a certain extent, the possibility of the two ends of the main body 112 along its own length direction being exposed and contacting and short-circuiting can be reduced.

[0134] In the battery cell 11 disclosed herein, the isolation portion 1142 may be an integral piece with the membrane body 1141 or may be connected to the membrane body 1141 by a fixed connection. Several implementations are described below.

[0135] In some embodiments of this application, please combine Figure 4 , Figures 7 to 11 The isolation portion 1142 and the membrane body 1141 may be an integral piece, and the isolation portion 1142 is bent from one of the two side edges of the membrane body 1141 to one side of the membrane body 1141 .

[0136] As an example, Figures 7 to 11As shown, one of the two sides of the membrane body 1141 facing the pole ear 113 is connected to the isolating portion 1142, and the isolating portion 1142 is integrated with the membrane body 1141. An exemplary preparation process of the composite layer structure 140 is roughly as follows: step 11, stacking the sheet-like diaphragm 114 on one side of the pole piece 111, and making the two ends of the sheet-like diaphragm 114 along the width direction of the pole piece 111 exceed the two edges of the main body 112; step 12, folding one end of the sheet-like diaphragm 114 along one edge of the main body 112 protruding with the pole ear 113 to the other side of the pole piece 111 to obtain the composite layer structure 140. Another exemplary preparation process of the composite layer structure 140 is as follows: Step 21, making a fold mark on the sheet-like diaphragm 114, folding the sheet-like diaphragm 114 along the fold mark, so that the diaphragm 114 becomes a membrane body 1141 and a separation part 1142 connected by a turning, and the separation part 1142 is bent from one of the two sides of the membrane body 1141 to one side of the membrane body 1141; Step 22, providing a pole piece 111, moving the diaphragm 114 obtained in step 21 or moving the pole piece 111, so that one of the edges of the main body 112 of the pole piece 111 with a pole ear 113 protruding therefrom moves between the membrane body 1141 and the separation part 1142. The fold mark may include a plurality of marking holes arranged at intervals along the length direction of the diaphragm 114, the centers of all the marking holes are located on the same straight line, and the marking holes may be formed by cutting with a cutter or by cutting with a laser head.

[0137] In contrast, when using steps 11 and 12 to prepare the composite layer structure 140, there is no need to make crease marks. The sheet-like diaphragm 114 only needs to be folded along the edge of the main body 112 to the other side of the pole piece 111, which can simplify the preparation process.

[0138] The isolation part 1142 is designed to be an integral part with the membrane body 1141. In this example, the isolation part 1142 can be formed by folding when preparing the composite layer structure 140. This can omit the connection process between the isolation part 1142 and the membrane body 1141, and is simple to manufacture. It can effectively improve the connection strength between the isolation part 1142 and the membrane body 1141 without increasing the cost, so as to reduce the risk of failure of the connection between the isolation part 1142 and the membrane body 1141 due to high temperature or the like, causing the membrane body 1141 to shrink and expose the edge of the main body 112.

[0139] In some embodiments of the present application, Figures 7 to 9 As shown, the isolation portion 1142 may be connected to a portion of one of the two sides of the membrane body 1141, and the remaining portion of one of the two sides of the membrane body 1141 extends beyond one of the two edges of the main body 112. Accordingly, one of the two edges of the main body 112 is on the same side as one of the two sides and is partially covered. The covered portion of one of the two edges may be located between two adjacent pole ears 113, such as Figure 7 It can also be located at both ends of the main body 112 along the length direction of the pole piece 111, such as Figure 8 shown.

[0140] As an example, when the isolation portion 1142 is connected to one of the two side edges located on the pole ear side of the pole piece 111 , the isolation portion 1142 and the pole ear 113 may be staggered with each other along the length direction of the pole piece 111 . Figure 7 and Figure 8 An exemplary preparation process of the composite layer structure 140 shown can be roughly as follows: Step 31, cutting off a portion of the sheet-like diaphragm 114 at one end along the width direction, so that the sheet-like diaphragm 114 becomes a membrane body 1141 and an isolation portion 1142, the isolation portion 1142 and the membrane body 1141 are located in the same plane, and the isolation portion 1142 protrudes from one of the two side edges of the membrane body 1141 and is connected to a portion of one of the two side edges; Step 32, stacking the diaphragm 114 obtained in Step 31 on one side of the pole piece 111, so that the isolation portion 1142 exceeds an edge of the main body 112 and is staggered with the pole ear 113; Step 33, folding the isolation portion 1142 along the edge of the main body 112 to the other side of the pole piece 111. Figure 7 and Figure 8 Another exemplary preparation process of the composite layer structure 140 shown can be roughly as follows: after step 31, the isolation portion 1142 is bent from one of the two side edges of the membrane body 1141 to the other side of the membrane body 1141, and the diaphragm 114 is moved or the pole piece 111 is moved so that part of one of the two edges of the main body 112 of the pole piece 111 is moved between the membrane body 1141 and the isolation portion 1142.

[0141] In some embodiments of the present application, the isolation portion 1142 may be connected to the entirety of one of the two sides of the membrane body 1141. Accordingly, one of the two edges of the main body 112 is on the same side as one of the two sides and is entirely covered.

[0142] As an example, when the isolating portion 1142 is completely connected to one of the two sides located on the non-ear side of the pole piece 111, the edge of the main body 112 located on the non-ear side is completely covered. Taking the isolating portion 1142 as an example, the preparation process of this example composite layer structure 140 can refer to the above steps 11 to 12, or can refer to the above steps 21 to 22.

[0143] As an example, Fig.10 and Fig.11As shown, when the isolating portion 1142 is completely connected to one of the two sides located on the pole ear side of the pole piece 111, the connection between the isolating portion 1142 and the membrane body 1141 is provided with avoidance holes that are the same in number as the pole ears 113 of the pole piece 111, and each pole ear 113 passes through the corresponding avoidance hole. In other words, one of the two edges of the main body 112 has a plurality of pole ears 113 protruding, and a plurality of avoidance holes are provided at the bend corresponding to the edge on the diaphragm 114, and the number of the avoidance holes is the same as the number of the pole ears 113.

[0144] Fig.10 An exemplary preparation process of the composite layer structure 140 shown is roughly as follows: step 41, providing a sheet-like diaphragm 114, cutting one end of the sheet-like diaphragm 114 along the width direction, so that a preset number of avoidance holes are cut out of one end of the sheet-like diaphragm 114; step 42, folding one end of the sheet-like diaphragm 114, so that the sheet-like diaphragm 114 becomes a plane part and an isolation part 1142 connected by a turning, and the avoidance hole is located at the turning connection between the plane part and the isolation part 1142; step 43, Move the pole piece 111 so that each pole ear 113 of the pole piece 111 is aligned one by one with each avoidance hole of the diaphragm 114 obtained in step 42, move the pole piece 111 or the diaphragm 114 so that each pole ear 113 passes through a corresponding avoidance hole, and the planar portion is overlapped on one side of the pole piece 111, and an edge of the pole piece 111 is located between the planar portion and the isolation portion 1142; step 44, fold the other end of the planar portion along the other edge of the main body 112 to the other side of the pole piece 111 to form the isolation portion 1142.

[0145] On the basis that the isolating portion 1142 and the membrane body 1141 are an integral part, in the technical solution in which the isolating portion 1142 is connected to a portion of one of the two side edges, the isolating portion 1142 can be conveniently staggered with the pole lug 113, so that the diaphragm 114 can cover a portion of one of the two edges of the main body 112 to reduce the possibility of edge exposure, and avoid the pole lug 113 without interfering with the pole lug 113. In the technical solution in which the isolating portion 1142 is completely connected to one of the two side edges, most of one of the two edges of the main body 112 is covered, and the possibility of exposure is small. When a pole lug 113 protrudes from one of the two edges of the main body 112, the diaphragm 114 and the pole lug 113 are prevented from interfering by opening an avoidance hole.

[0146] In some embodiments of the present application, the isolation portion 1142 and the membrane body 1141 may also be separate parts, and the membrane body 1141 and the isolation portion 1142 are fixedly connected.

[0147] The isolating portion 1142 and the membrane body 1141 are designed as separate parts, and the structure of the diaphragm 114 is more flexible. Isolating portions 1142 of different sizes are used. Accordingly, the diaphragm 114 can meet different design requirements.

[0148] There are various ways to connect the isolating portion 1142 to the membrane body 1141. For example, the isolating portion 1142 and the membrane body 1141 can be connected by bonding. For another example, the isolating portion 1142 and the membrane body 1141 can be connected by hot melt. By using bonding or hot melt connection, the connection method between the isolating portion 1142 and the membrane body 1141 is simple and reliable. For the sake of concise description, the hot melt connection method is used as an example for introduction below.

[0149] As an example, Figure 12 to Figure 13 As shown, only one of the two sides of the membrane body 1141 located on the pole ear side of the pole piece 111 is connected to the isolation portion 1142 , and the isolation portion 1142 and the membrane body 1141 are separate parts. Fig.12 An exemplary preparation process of the composite layer structure 140 shown in the figure is roughly as follows: step 51, providing a membrane body 1141 and a pole piece 111, stacking the membrane body 1141 on one side of the pole piece 111, and making the two side edges of the membrane body 1141 extend beyond the two edges of the main body 112 respectively; step 52, setting an isolation portion 1142 on the other side of the pole piece 111 and bonding or hot-pressing and fusing the isolation portion 1142 to one of the two side edges located on the pole ear side of the pole piece 111.

[0150] Fig.12 Another exemplary preparation process of the composite layer structure 140 shown in the figure is roughly as follows: step 61, stacking the isolation portion 1142 on one side of the membrane body 1141, and making the isolation portion 1142 opposite to one of the two side edges of the membrane body 1141; step 62, hot-melting the isolation portion 1142 and one of the two side edges of the membrane body 1141 located on the pole ear side of the pole piece 111; step 63, providing the pole piece 111, attaching the main body 112 of the pole piece 111 to a side of the membrane body 1141 facing the isolation portion 1142, and moving the pole piece 111 so that the pole ear 113 of the pole piece 111 passes through the portion that is not hot-melted between the isolation portion 1142 and one of the two side edges located on the pole ear side of the pole piece 111.

[0151] As an example, Fig.14 and Fig.15 As shown, both sides of the membrane body 1141 are connected with the isolation parts 1142 , and the two isolation parts 1142 and the membrane body 1141 are separate parts.

[0152] In some embodiments, the two isolation portions 1142 may belong to the same film layer 130, and the two isolation portions 1142 are formed by cutting the same film layer 130. Fig.16 As shown, Fig.14An exemplary preparation process of the composite layer structure 140 shown in the figure is roughly as follows: step 71, providing a membrane body 1141 and a pole piece 111, stacking the membrane body 1141 on one side of the pole piece 111, and making the two side edges of the membrane body 1141 respectively exceed the two edges of the main body 112; step 72, providing a membrane layer 130, stacking the membrane layer 130 on the other side of the pole piece 111, and making the two ends of the membrane layer 130 along the width direction of the pole piece 111 correspond to the two side edges of the membrane body 1141 respectively; step 73, hot-melt treatment is performed on the membrane body 1141 and the membrane layer 130, so that the two side edges of the membrane body 1141 and the two ends of the membrane layer 130 are hot-melt connected respectively; step 74, cutting off part of the membrane layer 130, and forming the remaining part into two isolation parts 1142 spaced apart along the width direction of the pole piece 111.

[0153] Fig.14 Another exemplary preparation process of the composite layer structure 140 shown in the figure is roughly as follows: step 81, providing a membrane body 1141 and a pole piece 111, stacking the membrane body 1141 on one side of the pole piece 111, and making the two side edges of the membrane body 1141 extend beyond the two edges of the main body 112 respectively; step 82, providing a membrane layer 130, cutting the membrane layer 130 into two isolation parts 1142; step 83, sequentially arranging the two isolation parts 1142 on the other side of the pole piece 111 and bonding or hot-pressing the two isolation parts 1142 to the two side edges respectively.

[0154] It can be seen that in the example where both sides of the membrane body 1141 are connected to the isolation parts 1142, the two isolation parts 1142 can be different parts of the same membrane layer 130. In this way, when preparing the composite layer structure 140, since the size of the membrane layer 130 is large, it is easy to operate, which can have a favorable effect on the preparation efficiency and preparation accuracy of the composite layer structure 140. Moreover, the shrinkage performance of the two isolation parts 1142 belonging to the same membrane layer 130 can be consistent, so that even if the diaphragm 114 shrinks, the shrinkage trends of the two isolation parts 1142 can be comparable. Among them, the shrinkage performance of the isolation part 1142 refers to parameters such as shrinkage temperature and shrinkage rate.

[0155] In some embodiments of the present application, the composite layer structure 140 is configured such that the diaphragm 114 has a glue layer. The glue layer may be located on the side of the surface of the diaphragm 114 facing the pole piece 111, the glue layer is connected to the pole piece 111, and / or the glue layer may be located on the side of the surface of the diaphragm 114 facing away from the pole piece 111.

[0156] Specifically, the diaphragm 114 includes a substrate and an adhesive layer. As an example, the diaphragm 114 is provided with an adhesive layer, which is located on one side of the substrate along its thickness direction and faces the surface of the pole piece 111, so that the pole piece 111 and the diaphragm 114 included in the composite layer structure 140 can be reliably connected by bonding, so that even if the diaphragm 114 shrinks by heat, it is limited by the bonding relationship and the shrinkage of the diaphragm 114 is limited, so that the edge of the main body 112 is exposed and the possibility of contact short circuit is small.

[0157] As an example, the diaphragm 114 is provided with a glue layer, which is located on one side of the substrate along its thickness direction and on the surface of the electrode 111 facing away from the composite layer structure 140, and the glue layer is bonded to other adjacent composite layer structures 140. In this way, even if the diaphragm 114 shrinks by heat, it is limited by the bonding relationship, so that the edge of the main body 112 is exposed and the possibility of contact short circuit is small.

[0158] As an example, the diaphragm 114 is provided with two adhesive layers, which are located on different sides of the substrate along its thickness direction, one adhesive layer facing the surface of the pole piece 111, and the other adhesive layer facing away from the surface of the pole piece 111. That is, adhesive layers are provided on both sides of the substrate.

[0159] The material of the adhesive layer can be selected from at least one of styrene-butadiene rubber, PCS polymer, etc. The PCS polymer melts at a certain temperature and has a bonding effect.

[0160] The diaphragm 114 is provided with an adhesive layer, which can play a bonding role. Even if the diaphragm 114 shrinks due to heat, the shrinkage of the diaphragm 114 is limited by the adhesive relationship, so that the edge of the main body 112 is exposed and the possibility of contact short circuit is small.

[0161] In some embodiments of this application, please combine Fig. 9 , Fig.11 , Fig.13 as well as Fig.15 , along the width direction of the pole piece 111, the membrane body 1141 is wider than the main body 112, and the two side edges respectively exceed the two edges by a distance of L. That is, the first side edge exceeds the first edge, and there is a spacing L between the first side edge and the first edge; the second side edge exceeds the second edge, and there is a spacing L between the second side edge and the second edge.

[0162] By configuring in this way, the portion of each side that exceeds the edge on the same side is reserved for heat shrinkage, thereby reducing the risk of the edge of the diaphragm 114 being exposed after heat shrinkage, resulting in contact short circuit.

[0163] In addition, it can also be understood that when there is no spacing between the side and the edge on the same side, the connection between the side connected with the isolation part 1142 and the isolation part 1142 abuts against the edge of the main body 112. If the internal temperature of the battery cell 11 reaches the shrinkage temperature, the diaphragm 114 shrinks due to heat and gradually tightens, and the abutment stress between the connection between the side and the isolation part 1142 and the edge of the main body 112 increases accordingly, causing the connection between the side and the isolation part 1142 to be easily broken. In this embodiment, when any side is connected with the isolation part 1142, since there is a spacing L between the side and the edge on the same side, this can at least reduce the possibility of the connection between the side and the isolation part 1142 abutting against the edge of the main body 112 to a certain extent, and further reduce the possibility of the connection between the side and the isolation part 1142 being excessively squeezed and broken during the heat shrinkage of the diaphragm 114.

[0164] When the tab 113 of the cathode electrode sheet 111A and the tab 113 of the anode electrode sheet 111B are led out from the first edge of their respective main bodies 112, that is, the tab 113 of the cathode electrode sheet 111A and the tab 113 of the anode electrode sheet 111B are located on the same side of the electrode assembly 110 and both face the top wall of the outer shell 120, the portion of the second side that extends beyond the second edge can be bent and folded and placed on the bottom wall of the outer shell 120.

[0165] In some embodiments of the present application, L may satisfy: 2 mm≤L≤10 mm.

[0166] Among them, L can be any value among 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm and 10 mm.

[0167] In this design, the value of L is moderate. On the one hand, L is not too small, that is, a certain margin is reserved for shrinkage, so that the risk of the edge of the diaphragm 114 being exposed due to heat shrinkage is small. On the other hand, L is not too large, so that more electrolyte can be accommodated in the housing 120, which is conducive to improving the energy density of the battery cell 11.

[0168] In some embodiments of the present application, based on the implementation scheme in which both side edges extend beyond the two edges respectively, one of the two side edges located on the pole ear side of the pole piece 111 can also be bonded and connected to the pole ear 113 .

[0169] Here, when the diaphragm 114 has an adhesive layer, the diaphragm 114 can use its own adhesive layer to make the part surrounding the pole tab 113 bonded to the pole tab 113. Alternatively, the pole tab 113 can be coated with an adhesive, and the part surrounding the pole tab 113 is bonded to the pole tab 113 through the adhesive.

[0170] As an example, a method for achieving bonding connection between one of the two side edges located on the pole ear side of the pole piece 111 and the pole ear 113 may also be specifically as follows: one of the two side edges located on the pole ear side of the pole piece 111 is heated at high temperature so that the side edge melts at high temperature to adhere to the pole ear 113; after a period of time, the side edge cools down and is bonded to the pole ear 113.

[0171] When one of the two side edges located at the pole ear side of the pole piece 111 is connected with the isolating portion 1142 , the isolating portion 1142 is also bonded and connected to the pole ear 113 .

[0172] By designing the diaphragm 114 so that the portion of the side extending beyond the edge of the same side is bonded and connected to the pole lug 113, the portion of the side extending beyond the edge of the same side is fixed to the pole lug 113, and limited by the connection relationship, even if the diaphragm 114 shrinks, the edge of the pole lug 113 on the main body 112 is less likely to be exposed.

[0173] In some embodiments of the present application, the distance between the two side edges and the two edges is L, the width of the main body 112 is h, and the dimension of the isolation portion 1142 along the width direction of the pole piece 111 is H, and H can be designed to satisfy: L<H<L+0.5×h.

[0174] On the one hand, by designing H>L, HL>0 mm, the edge of the isolating portion 1142 extends from one of the two side edges of the membrane body 1141 along the width direction of the pole piece 111 to between the two edges of the main body 112, so that at least part of one of the two edges of the main body 112 can be covered. On the other hand, by designing H<L+0.5×h, the edge of the isolating portion 1142 does not exceed the middle of the main body 112. If the diaphragm 114 is provided with two isolating portions 1142, a certain distance between the two isolating portions 1142 can be ensured.

[0175] In some embodiments of the present application, H may be designed to satisfy: 2 mm<H≤15 mm.

[0176] Among them, H can be any value among 2.5 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, 11 mm, 12 mm, 13 mm, 14 mm and 15 mm.

[0177] With such a design, under the premise that H can satisfy L<H<L+0.5×h, since H≤15 mm, H can also be prevented from being too large, that is, the overlapping part of the membrane body 1141 and the isolation part 1142 has a small size along the width direction of the main body 112. This has a favorable effect on reducing the difficulty of manufacturing the diaphragm 114 when the diaphragm 114 is also constructed with a total thickness that is equal everywhere.

[0178] In some embodiments of the present application, the total thickness D of the diaphragm 114 can be equal everywhere; the membrane body 1141 has a stacked part and a non-stacked part, the orthographic projection of the isolation part 1142 on the surface of the membrane body 1141 along the thickness direction coincides with the stacked part, the thickness of the non-stacked part is equal to D, and the sum of the thickness of the isolation part 1142 and the thickness of the stacked part is equal to D.

[0179] As an example, the thickness of the stacked portion may be uniform everywhere and equal to d1, and the thickness of the isolation portion 1142 may be uniform everywhere and equal to d2, where d1+d2=D.

[0180] In the example where the diaphragm 114 is an integral piece and the diaphragm 114 is bent to form the isolation portion 1142, an exemplary preparation process of the sheet-type diaphragm 114 in the above steps 11, 21, 31 and 41 is roughly as follows: step a, providing a base film, the base film is a continuous sheet-type structure, and the thickness of the base film is the same everywhere and is 0.5D; step b, coating a portion of the surface of the base film with a coating, and making the thickness of the coating the same everywhere and is 0.5D, then the thickness of the coated portion is D, and the coated portion is the non-laminated portion.

[0181] In the example where the diaphragm 114 is a split part, an exemplary preparation process of the membrane body 1141 in the above steps 51, 61, 71 and 81 is roughly as follows: step i, providing an initial membrane; wherein the thickness of the initial membrane is the same everywhere and is d1; step ii, coating a portion of the surface of the initial membrane with a coating, and making the thickness of the coating the same everywhere and equal to the thickness d2 of the isolation portion 1142, to obtain the membrane body 1141, the portion of the membrane body 1141 coated with the coating is the non-laminated portion, and the portion not coated with the coating is the laminated portion.

[0182] As an example, the thickness of the stacked portion and the thickness of the isolation portion 1142 may not be equal everywhere, as long as the sum of the thicknesses of the two is D.

[0183] The coating may be any one or more of an inorganic coating, an organic coating, and an adhesive layer, and this embodiment does not impose any specific limitation on this.

[0184] On the basis that the diaphragm 114 can cover at least one of the two edges of the main body 112, so that the possibility of the edge of the main body 112 being exposed is reduced, this embodiment designs the diaphragm 114 to have a total thickness that is equal everywhere, and can also make the electrode assembly 110 smoothly enter the shell, ensuring that the battery cell 11 can be assembled smoothly.

[0185] As for the battery cell 11 disclosed herein, the material of the isolation membrane may be polypropylene (PP) or polyethylene (PE), etc., and this embodiment does not impose any specific limitation on this.

[0186] The present application also proposes a method for manufacturing a battery cell 11 , which mainly includes the following steps.

[0187] S100 , providing two pole pieces 111 with opposite polarities, the pole piece 111 having a main body 112 and a pole ear 113 , the main body 112 having two opposite edges along its width direction, and the pole ear 113 protruding from one of the two edges from the main body 112 .

[0188] S200, each pole piece 111 and a diaphragm 114 are compounded to obtain a composite layer structure 140; wherein the diaphragm 114 has a connected membrane body 1141 and an isolation portion 1142, and the membrane body 1141 has two side edges along the width direction of the pole piece 111, and the two side edges are respectively on the same side as the two edges; the composite layer structure 140 is configured so that at least one of the two side edges located on the pole ear side of the pole piece 111 is connected to the isolation portion 1142, and the main body 112 of the pole piece 111 is located between the membrane body 1141 and the isolation portion 1142, and the composite layer structure 140 is configured so that the pole ear 113 does not interfere with the diaphragm 114.

[0189] Among them, one of the two side edges located on the pole ear side of the pole piece 111 is connected to an isolation portion 1142, an edge of the pole ear 113 protruding from the main body 112 is covered, and the other of the two side edges extends to exceed the other of the two edges of the main body 112, or, both side edges are connected to an isolation portion 1142, the two isolation portions 1142 are located on the same side of the membrane body 1141, and the two isolation portions 1142 are spaced apart along the width direction of the pole piece 111.

[0190] S300 , winding the two composite layer structures 140 around a winding axis to obtain an electrode assembly 110 .

[0191] S400 , the electrode assembly 110 is installed in the housing 120 to obtain the battery cell 11 .

[0192] It should be noted that the battery cell 11 manufactured by the manufacturing method provided in the above embodiments has a wound electrode assembly 110 . The relevant structure of the electrode assembly 110 can refer to the electrode assembly 110 provided in the above embodiments, and will not be described again here.

[0193] The present application also proposes a method for manufacturing a battery cell 11 , which mainly includes the following steps.

[0194] S500 , providing a plurality of pole pieces 111 , wherein the pole pieces 111 have a main body 112 and a pole ear 113 , wherein the main body 112 has two opposite edges along its width direction, and the pole ear 113 protrudes from the main body 112 from one of the two edges.

[0195] S600, compound each pole piece 111 and a diaphragm 114 to obtain a composite layer structure 140; wherein the diaphragm 114 has a connected membrane body 1141 and an isolation portion 1142, the membrane body 1141 has two side edges along the width direction of the pole piece 111, and the two side edges are respectively on the same side as the two edges; the composite layer structure 140 is configured so that at least one of the two side edges located on the pole ear side of the pole piece 111 is connected to the isolation portion 1142, and the main body 112 of the pole piece 111 is located between the membrane body 1141 and the isolation portion 1142, and the composite layer structure 140 is configured so that the pole ear 113 does not interfere with the diaphragm 114.

[0196] S700 , stacking a plurality of composite layer structures 140 to form an electrode assembly 110 , and making the polarities of two adjacent pole pieces 111 of the electrode assembly 110 opposite.

[0197] S800 , the electrode assembly 110 is installed in the housing 120 to obtain the battery cell 11 .

[0198] It should be noted that the battery cell 11 manufactured by the manufacturing method provided in the above embodiments has a laminated electrode assembly 110 . The relevant structure of the electrode assembly 110 can be found in the electrode assembly 110 provided in the above embodiments, and will not be described in detail here.

[0199] Regardless of whether the electrode assembly 110 of the battery cell 11 is a winding structure or a laminated structure, the preparation process of the composite layer structure 140 of the electrode assembly 110 is similar. That is, the specific implementation process of the above step S200 and the above step S600 is similar. The specific implementation process of step S200 and the above step S600 is described in detail below.

[0200] In some embodiments of the present application, when the membrane body 1141 and the isolation portion 1142 are an integral piece, the specific implementation process of compounding each pole piece 111 and a diaphragm 114 to obtain the composite layer structure 140 can refer to the above steps 11 to 12, or can also refer to the above steps 21 to 22.

[0201] In contrast, when using steps 11 and 12 to prepare the composite layer structure 140, there is no need to make crease marks. The sheet-like diaphragm 114 only needs to be folded along the edge of the main body 112 to the other side of the pole piece 111, which can simplify the preparation process.

[0202] In some embodiments of the present application, when the isolation portion 1142 and the membrane body 1141 are separate parts, the specific implementation process of compounding each pole piece 111 and a diaphragm 114 to obtain the composite layer structure 140 can refer to the above steps 51 and 52, or can also refer to the above steps 71 to 74, or can also refer to the above steps 81 to 83.

[0203] In general, when the isolation portion 1142 and the membrane body 1141 are separate parts, the specific implementation process of compounding each pole piece 111 and a diaphragm 114 to obtain the composite layer structure 140 includes S11 and S12 or S13 after S11.

[0204] S11 , providing a membrane body 1141 and a pole piece 111 , stacking the membrane body 1141 on one side of the pole piece 111 , and making two side edges of the membrane body 1141 extend beyond two edges of the pole piece 111 .

[0205] S12 , disposing an isolating portion 1142 on the other side of the pole piece 111 and bonding or hot-pressing and fusing the isolating portion 1142 to one of the two side edges located on the pole ear side of the pole piece 111 to obtain a composite layer structure 140 .

[0206] S13 , disposing two isolation parts 1142 on the other side of the pole piece 111 and bonding or hot-pressing and fusing the two isolation parts 1142 to the two side edges to obtain a composite layer structure 140 .

[0207] As an example, the implementation process of S13 may be: providing a film layer 130, cutting the film layer 130 into two isolation parts 1142, sequentially arranging the two isolation parts 1142 on the other side of the pole piece 111 and respectively bonding or hot-pressing the two isolation parts 1142 to the two side edges.

[0208] As an alternative example, the implementation process of S13 can also be: provide a film layer 130, set the film layer 130 on the other side of the pole piece 111, respectively bond or hot-press the two ends of the film layer 130 along the width direction of the pole piece 111 to the two side edges, and cut the film layer 130 into two isolation parts 1142. In this way, the two isolation parts 1142 belong to the same film layer 130, so that when preparing the composite layer structure 140, the size of the film layer 130 is larger and easy to operate. Moreover, the shrinkage performance of the two isolation parts 1142 belonging to the same film layer 130 can be consistent.

[0209] In some embodiments of the present application, further, before providing a membrane body 1141 and a pole piece 111, the manufacturing method of the battery cell 11 may further include step i and step ii. With this design, the total thickness D of the prepared diaphragm 114 is equal everywhere, so that on the basis of reducing the possibility of the edge of the main body 112 being exposed, the electrode assembly 110 can be smoothly inserted into the shell, ensuring that the battery cell 11 can be assembled smoothly.

[0210] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below.

[0211] Embodiment 1

[0212] In the implementation mode of the present application, Figures 2 to 8 As shown, the present application proposes a battery cell 11, comprising a housing 120 and an electrode assembly 110 contained in the housing 120. The electrode assembly 110 is a winding structure or a laminated structure.

[0213] When the electrode assembly 110 is a wound structure, the electrode assembly 110 includes two pole pieces 111 and two separators 114. Each pole piece 111 and one separator 114 form a composite layer structure 140. The two pole pieces 111 are respectively a cathode pole piece 111A and an anode pole piece 111B. That is, the wound electrode assembly 110 is formed by stacking two composite layer structures 140 and winding them along a winding axis.

[0214] When the electrode assembly 110 is a laminated structure, the electrode assembly 110 includes a plurality of pole pieces 111 and a plurality of diaphragms 114, and each diaphragm 114 and a pole piece 111 are configured to form a composite layer structure 140. That is, the laminated electrode assembly 110 is formed by stacking a plurality of composite layer structures 140, and the composite layer structures 140 having the cathode pole piece 111A and the composite layer structures 140 having the anode pole piece 111B are alternately arranged along the stacking direction.

[0215] The pole piece 111 includes a main body 112 and a pole ear 113. The main body 112 has opposite first and second edges along its width direction, and the pole ear 113 protrudes from the first edge of the main body 112. The diaphragm 114 includes a connected membrane body 1141 and a separation part 1142. The membrane body 1141 has opposite first and second sides along the width direction of the pole piece 111, the first side and the first edge are located on the same side, and the second side and the second edge are located on the other side. The membrane body 1141 and the separation part 1142 are an integral part, and the sheet-like diaphragm 114 is bent to form the separation part 1142.

[0216] Regardless of whether the electrode assembly 110 is a winding structure or a laminated structure, the composite layer structure 140 may be formed in any of the following ways.

[0217] In one possible implementation, the first side of the membrane body 1141 is connected to the isolating portion 1142, the main body 112 is located between the membrane body 1141 and the isolating portion 1142, the first edge of the main body 112 is covered, and the second side extends beyond the second edge of the main body 112. The isolating portion 1142 is connected to a portion of the first side, the portion of the first side not connected to the isolating portion 1142 exceeds the first edge, the isolating portion 1142 and the pole lug 113 are staggered along the length direction of the pole piece 111, or the isolating portion 1142 is connected to the entire first side, and the connection between the two is provided with avoidance holes of the same number as the pole lug 113.

[0218] In another possible implementation, the first side and the second side of the membrane body 1141 are respectively connected to an isolating portion 1142, the two isolating portions 1142 are located on the same side of the membrane body 1141, the main body 112 is located between the membrane body 1141 and the isolating portion 1142, and the two isolating portions 1142 are spaced apart along the width direction of the pole piece 111. The isolating portion 1142 is connected to a portion of the first side, the portion of the first side not connected to the isolating portion 1142 exceeds the first edge, the isolating portion 1142 and the pole lug 113 are staggered along the length direction of the pole piece 111, or the isolating portion 1142 is connected to the entire first side, and the connection between the two is provided with avoidance holes of the same number as the pole lug 113.

[0219] Furthermore, the first side exceeds the first edge, and there is a spacing L between the two along the width direction of the pole piece 111, 2mm≤L≤10mm. The second side exceeds the second edge, and there is a spacing L between the two along the width direction of the pole piece 111, 2mm≤L≤10mm.

[0220] Furthermore, the dimension of the isolation portion 1142 along the width direction of the pole piece 111 is H, 2 mm<H≤15 mm.

[0221] Furthermore, the total thickness D of the diaphragm 114 is equal everywhere.

[0222] Furthermore, the diaphragm 114 has an adhesive layer, which is located on a side of the diaphragm 114 facing the surface of the pole piece 111 , so that the pole piece 111 and the diaphragm 114 constituting the composite layer structure 140 are bonded and connected.

[0223] Embodiment 2

[0224] This embodiment is similar to the first embodiment, except that: in the first embodiment, the membrane body 1141 and the isolation part 1142 are an integral part, and the sheet-like diaphragm 114 is bent to form the isolation part 1142, while in this embodiment, the membrane body 1141 and the isolation part 1142 are separate parts, and the membrane body 1141 and the isolation part 1142 are bonded or hot-melt connected. When the first side and the second side of the membrane body 1141 are respectively connected to an isolation part 1142, the two isolation parts 1142 are formed by cutting the same membrane layer 130.

[0225] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them; although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application, and they should all be included in the scope of the claims and specification of the present application. In particular, as long as there is no structural conflict, the various technical features mentioned in the various embodiments can be combined in any way. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions that fall within the scope of the claims.

Claims

1. A battery cell, characterized in that: include: shell; as well as An electrode assembly, contained in the housing, comprising a plurality of diaphragms and a plurality of pole pieces; The pole piece has a main body and a pole ear, the main body has two edges facing each other along its width direction, and the pole ear protrudes from the main body from one of the two edges; the diaphragm has a connected membrane body and a separation part, the membrane body has two side edges along the width direction of the pole piece, and the two side edges are respectively on the same side as the two edges; two adjacent pole pieces with opposite polarities among the plurality of pole pieces are respectively configured into a composite layer structure with one of the diaphragms, and the diaphragms can separate the two pole pieces; Among them, the composite layer structure is configured so that at least one of the two side edges located on the pole ear side of the pole piece is connected to the isolation part, and the main body of the pole piece is located between the membrane body and the isolation part, and the composite layer structure is also configured so that the pole ear does not interfere with the diaphragm.

2. The battery cell according to claim 1, characterized in that: The membrane body and the isolation part are an integral piece.

3. The battery cell according to claim 2, characterized in that: The isolation portion is connected to a portion of one of the two side edges of the membrane body, and one of the two edges is on the same side as and partially covered by one of the two side edges.

4. The battery cell according to claim 3, characterized in that: When the isolating portion is connected to one of the two side edges located on the pole ear side of the pole piece, the isolating portion and the pole ear are staggered with each other along the length direction of the pole piece.

5. The battery cell according to claim 2, characterized in that: The isolation portion is completely connected to one of the two side edges of the membrane body, and one of the two edges is on the same side as one of the two side edges and is entirely covered.

6. The battery cell according to claim 5, characterized in that: One of the two edges is provided with a plurality of the pole ears protruding therefrom, and a plurality of avoidance holes are provided at the connection between the isolation portion and the membrane body. The number of the avoidance holes is the same as the number of the pole ears, and each pole ear passes through the corresponding avoidance hole.

7. The battery cell according to claim 1, characterized in that: The isolation part and the membrane body are separate parts, and the membrane body and the isolation part are fixedly connected.

8. The battery cell according to claim 7, characterized in that: The membrane body and the isolation part are bonded together, or the membrane body and the isolation part are thermally melted together.

9. The battery cell according to any one of claims 1 to 8, characterized in that: The diaphragm has a glue layer; The adhesive layer is located on a side of a surface of the diaphragm facing the pole piece, the adhesive layer is connected to the pole piece, and / or the adhesive layer is located on a side of a surface of the diaphragm facing away from the pole piece.

10. The battery cell according to any one of claims 1 to 8, characterized in that: Along the width direction of the pole piece, the membrane body is wider than the main body, and the two side edges respectively exceed the two edges.

11. The battery cell according to claim 10, characterized in that: The distance that the two side edges extend beyond the two edges is L, and L satisfies: 2mm≤L≤10mm.

12. The battery cell according to claim 10, characterized in that: One of the two side edges located on the pole ear side of the pole piece is bonded to the pole ear.

13. The battery cell according to claim 10, characterized in that: The distance that the two side edges extend beyond the two edges is L, the width of the main body is h, and the dimension of the isolation portion along the width direction of the pole piece is H, and H satisfies: L<H<L+0.5×h.

14. The battery cell according to claim 13, characterized in that: The H satisfies: 2mm<H≤15mm.

15. The battery cell according to any one of claims 1 to 8, characterized in that: The total thickness D of the diaphragm is equal everywhere; the membrane body has a stacked part and a non-stacked part, the orthographic projection of the isolation part on the surface of the membrane body along the thickness direction coincides with the stacked part, the thickness of the non-stacked part is equal to D, and the sum of the thickness of the isolation part and the thickness of the stacked part is equal to D.

16. The battery cell according to any one of claims 1 to 8, characterized in that: The two side edges are both connected with the isolation parts, the two isolation parts are located on the same side of the membrane body, and the two isolation parts are spaced apart along the width direction of the pole piece.

17. A battery device, characterized in that: include: A battery cell according to any one of claims 1 to 16.

18. An electrical device, characterized in that: include: The battery device according to claim 17, wherein the battery device is used to provide electrical energy.

19. A method for manufacturing a battery cell, characterized in that: include: Providing two pole pieces with opposite polarities, the pole pieces having a main body and a pole ear, the main body having two opposite edges along its width direction, the pole ear protruding from one of the two edges from the main body; Each pole piece and a diaphragm are compounded to obtain a composite layer structure; wherein the diaphragm has a connected membrane body and a separation portion, the membrane body has two side edges along the width direction of the pole piece, and the two side edges are respectively on the same side as the two edges; the composite layer structure is configured so that at least one of the two side edges located on the pole ear side of the pole piece is connected to the separation portion, and the main body of the pole piece is located between the membrane body and the separation portion, and the composite layer structure is also configured so that the pole ear does not interfere with the diaphragm; Winding the two composite layer structures around a winding axis to obtain an electrode assembly; The electrode assembly is housed in a housing to obtain a battery cell.

20. A method for manufacturing a battery cell, characterized in that: include: Providing a plurality of pole pieces, each pole piece having a main body and a pole ear, wherein the main body has two edges facing each other along its width direction, and the pole ear protrudes from the main body from one of the two edges; Each pole piece and a diaphragm are compounded to obtain a composite layer structure; wherein the diaphragm has a connected membrane body and a separation portion, the membrane body has two side edges along the width direction of the pole piece, and the two side edges are respectively on the same side as the two edges; the composite layer structure is configured so that at least one of the two side edges located on the pole ear side of the pole piece is connected to the separation portion, and the main body of the pole piece is located between the membrane body and the separation portion, and the composite layer structure is also configured so that the pole ear does not interfere with the diaphragm; Stacking a plurality of the composite layer structures to form an electrode assembly, and making the polarities of two adjacent pole pieces of the electrode assembly opposite; The electrode assembly is housed in a housing to obtain a battery cell.

21. The method for manufacturing a battery cell according to claim 19 or 20, characterized in that: In the case where the membrane body and the isolation portion are integrally formed, The composite layer structure obtained by composite each pole piece and a diaphragm specifically includes: Stacking a sheet-like diaphragm on one side of the pole piece, and making both ends of the sheet-like diaphragm along the width direction of the pole piece exceed the two edges respectively; At least one end of the sheet-like diaphragm is folded toward the other side of the pole piece to form an isolation portion, so as to obtain the composite layer structure.

22. The method for manufacturing a battery cell according to claim 19 or 20, characterized in that: In the case where the isolation portion and the membrane body are separate parts, The composite layer structure obtained by composite each pole piece and a diaphragm specifically includes: Providing a membrane body and a pole piece, stacking the membrane body on one side of the pole piece, and making the two side edges of the membrane body exceed the two edges respectively; An isolating portion is arranged on the other side of the pole piece and the isolating portion is bonded or hot-pressed to one of the two side edges located on the pole ear side of the pole piece to obtain the composite layer structure, or two isolating portions are arranged on the other side of the pole piece and the two isolating portions are bonded or hot-pressed to the two side edges to obtain the composite layer structure.

23. The method for manufacturing a battery cell according to claim 22, characterized in that: The step of arranging two isolation parts on the other side of the pole piece and bonding or hot-pressing the two isolation parts to the two side edges to obtain the composite layer structure specifically includes: Providing a film layer, cutting the film layer into two isolation parts, sequentially arranging the two isolation parts on the other side of the pole piece, and bonding or hot-pressing the two isolation parts to the two side edges respectively; or, A film layer is provided, and the film layer is arranged on the other side of the pole piece, and the two ends of the film layer along the width direction of the pole piece are respectively bonded or hot-pressed to the two side edges, and the film layer is cut into the two isolation parts.

24. The method for manufacturing a battery cell according to claim 22, characterized in that: Before providing a membrane body and a pole piece, the method further includes: Providing an initial film; wherein the thickness of the initial film is the same everywhere and is d1; A coating layer is coated on a portion of the surface of the initial film, and the thickness of the coating layer is made uniform everywhere and equal to the thickness d2 of the isolation portion, so as to obtain the film body.

Images