WO2024045276A1

WO2024045276A1 - Battery cell, battery, and electric device

Info

Publication number: WO2024045276A1
Application number: PCT/CN2022/125090
Authority: WO
Inventors: 梁加浩; 杨彦超; 唐代春
Original assignee: 宁德时代新能源科技股份有限公司
Priority date: 2022-08-29
Filing date: 2022-10-13
Publication date: 2024-03-07
Also published as: CN217768421U

Abstract

The present application relates to a battery cell, a battery, and an electric device. The battery cell comprises an electrode assembly and an insertion connection assembly. The electrode assembly comprises a straight portion and bending portions arranged on two sides of the straight portion in a first direction. The insertion connection assembly is inserted between two adjacent folds of an electrode sheet in the bending portion on at least one side in a winding axis direction of the electrode assembly. In the battery cell of the present application, the insertion connection assembly is inserted between the two adjacent folds of the electrode sheet in the bending portion of the electrode assembly in the winding axis direction of the electrode assembly, and thus occupies a certain space in the bending portion, such that the two adjacent folds of the electrode sheet in the bending portion are spaced apart by a certain gap, thereby reducing the risk that lithium precipitation occurs between the two adjacent folds of the electrode sheet, and improving the reliability of use of the battery cell.

Description

Battery cells, batteries and electrical devices

cross reference

This application claims priority to Chinese patent application CN202222276139.1 titled "Battery Cells, Batteries and Electrical Devices" submitted on August 29, 2022, the entire content of which is incorporated herein by reference.

Technical field

The present application relates to the technical field of secondary batteries, and in particular to a battery cell, a battery and an electrical device.

Background technique

Energy conservation and emission reduction are key factors for the sustainable development of production and life. Therefore, secondary batteries are increasingly used in people's daily lives.

Secondary batteries are generally divided into stacked structures or rolled structures. For secondary batteries with rolled structures, during the production process, the pole pieces need to be wound, and hot or cold pressed after winding. During the process, lithium precipitation is likely to occur due to inconsistent gaps between the pole pieces at the corners, affecting the normal use of the secondary battery.

Contents of the invention

Based on this, it is necessary to provide a battery cell, a battery and an electrical device to solve the problem of lithium precipitation caused by inconsistent gaps between pole pieces in the battery and affecting the normal use of the battery.

According to one aspect of the present application, an embodiment of the present application provides a battery cell, including: an electrode assembly, the electrode assembly includes a straight portion and bent portions provided on both sides of the straight portion along a first direction; and a plug connector. The assembly is inserted between two adjacent layers of pole pieces in the bent portion on at least one side along the winding axis direction of the electrode assembly.

In the above-mentioned battery cell, the plug-in assembly is inserted between two adjacent layers of pole pieces in the bent portion of the electrode assembly along the winding axis direction of the electrode assembly. Since the plug-in assembly occupies a certain space in the bent portion, , it is possible to maintain a certain gap between two adjacent layers of pole pieces in the bent part, reduce the risk of lithium precipitation between two adjacent layers of pole pieces, and improve the reliability of the battery cells.

In one embodiment, the plug-in assembly includes a plurality of plug-in connectors, and each plug-in connector is inserted between two adjacent layers of pole pieces in the bent portion. Such a design allows plug connectors to be inserted between two different adjacent layers of pole pieces in the bent portion, so that a certain gap is maintained between the multiple layers of pole pieces in the bent portion.

In one of the embodiments, the plug component further includes a fixing base, the fixing base extends along the first direction, and one end of each plug connector protrudes outside the bending portion and is connected to the fixing base. By protruding one end of each plug-in connector out of the bending portion and connecting it to the fixed base, the position of each plug-in connector is kept fixed relative to the electrode assembly and does not move in the electrode assembly.

In one embodiment, the length of the plug connector protruding out of the bending portion is no more than 5 millimeters (mm). This design enables an appropriate gap to be maintained between the holder and the electrode assembly, which reduces the overall space occupied by the battery cell without affecting the normal use of the electrode assembly.

In one embodiment, the plug connectors are arranged side by side along the first direction on the fixed base, and two adjacent plug connectors are spaced apart from each other. By arranging the plug-in connectors side by side and spaced apart from each other along the first direction on the fixed base, that is, the arrangement direction of the plug-in connectors is kept parallel to the arrangement direction of the bending portion. In this way, each plug-in connector can be evenly inserted on the fixed base. In the bent part, the gaps between the pole pieces in the bent part are made more uniform.

In one embodiment, along the longitudinal extension direction of the plug connector, the projected outline of the plug connector on the surface of the fixing base is circular, linear, folded or arc-shaped. By arranging plug connectors of different shapes, the position of the plug connector in the gap between two adjacent layers of pole pieces in the bending part can be adjusted without changing the spacing between two adjacent plug connectors. The size of the occupied space, that is, adjusting the gap size between two adjacent layers of pole pieces, can be adapted to different usage needs.

In one embodiment, the plug connector is provided with a plurality of liquid storage holes. The liquid storage hole on the connector can absorb and store the electrolyte through capillary phenomenon, so that the electrolyte can diffuse between the two adjacent layers of pole pieces with the help of the connector, ensuring that the bent part can be wetted by the electrolyte, further Reduce the risk of lithium precipitation in electrode components.

In one embodiment, the liquid storage hole includes a through hole and/or a blind hole. Providing through holes on the connector can serve as a storage space and transmission channel for the electrolyte, while providing blind holes can serve as a storage space for the electrolyte, allowing the connector to absorb the electrolyte and wet the bent portion.

In one embodiment, the diameter of the liquid storage hole is greater than or equal to 1 micrometer (μm) and less than or equal to 10 micrometer (μm). Properly setting the diameter of the liquid storage hole not only facilitates the arrangement of the liquid storage hole, but also enables the connector to absorb enough electrolyte to ensure the infiltration effect on the bending part.

In one embodiment, the porosity of the plug connector is greater than or equal to 30% and less than or equal to 50%. Properly setting the porosity of the plug connector not only facilitates the processing of the plug connector, but also enables the plug connector to absorb enough electrolyte to ensure the infiltration effect on the bending part.

In one embodiment, the connector is made of polyethylene or polypropylene. This design makes the connector have excellent physical and chemical properties, is easy to process and manufacture, and has low cost.

In one embodiment, a diaphragm is provided between two adjacent layers of pole pieces in the bent portion, and the plug-in component is inserted between the pole pieces and the diaphragm. By inserting the plug assembly between the pole piece and the separator in the bent portion, a certain gap is maintained between the pole piece and the separator, thereby reducing the risk of lithium precipitation in the pole piece and improving the reliability of the battery cells.

In one of the embodiments, the plug component is attached to the side of its corresponding pole piece facing the bending center of the bending portion. By attaching the plug-in component to the side of the corresponding pole piece facing the bending center of the bending part, the plug-in component is brought into contact with the depression of the corresponding pole piece in the bending part, thereby avoiding the center of the bending part. Stress concentration occurs on the pole pieces, which reduces the risk of lithium precipitation on the pole pieces and improves the reliability of the battery cells.

According to another aspect of the present application, an embodiment of the present application also provides a battery, including: a box; and a plurality of battery cells as described above, and the battery cells are accommodated in the box.

In the above-mentioned battery, by using the above-mentioned battery cell, the plug-in component is inserted between two adjacent layers of pole pieces in the bent part of the electrode assembly. Since the plug-in component occupies a certain space in the bent part, it can This allows a certain gap to be maintained between two adjacent layers of pole pieces in the bent portion, thereby reducing the risk of lithium precipitation between the two adjacent layers of pole pieces and improving the reliability of the battery cells.

According to another aspect of the present application, an embodiment of the present application also provides an electrical device, including: the above-mentioned battery, and the battery is used to provide electric energy.

The above-mentioned electric device uses the above-mentioned battery to provide electric energy. Since the battery has high reliability, the safety of the electric device is also higher.

Description of drawings

Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The drawings are for the purpose of illustrating preferred embodiments only and are not to be construed as limiting the application. Also, the same parts are represented by the same reference numerals throughout the drawings. In the attached picture:

Figure 1 is a schematic diagram of the overall structure of a vehicle provided by an embodiment of the present application;

Figure 2 is an exploded view of the overall structure of a battery provided by an embodiment of the present application;

Figure 3 is a cross-sectional view of the overall structure of a battery cell provided by an embodiment of the present application;

Figure 4 is a partial enlarged schematic diagram of position A in Figure 3;

Figure 5 is a schematic structural diagram of a plug-in assembly in a battery cell according to an embodiment of the present application;

Figure 6 is a schematic structural diagram of a plug-in assembly in a battery cell according to another embodiment of the present application;

Figure 7 is a schematic structural diagram of a plug-in component in a battery cell according to another embodiment of the present application.

The reference numbers in the specific implementation are as follows:

1: Electrical device;

10: Battery;

100: battery cell;

110: Electrode assembly, 111: Straight part, 112: Bent part, 113: Pole piece, 114: Diaphragm;

120: plug-in component, 121: plug-in connector, 122: fixed seat;

200: box;

a: first direction.

Detailed ways

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

Unless otherwise defined, all technical and scientific terms used herein have the same meanings as commonly understood by those skilled in the technical field belonging to this application; the terms used herein are for the purpose of describing specific embodiments only and are not intended to be used in Limitation of this application; the terms "including" and "having" and any variations thereof in the description and claims of this application and the above description of the drawings are intended to cover non-exclusive inclusion.

In the description of the embodiments of this application, the technical terms "first", "second", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying the relative importance or implicitly indicating the quantity or specificity of the indicated technical features. Sequence or priority relationship. In the description of the embodiments of this application, "plurality" means two or more, unless otherwise explicitly and specifically limited.

Reference herein to "an embodiment" means that a particular feature, structure or characteristic described in connection with the embodiment can be included in at least one embodiment of the present application. The appearances of this phrase in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. Those skilled in the art understand, both explicitly and implicitly, that the embodiments described herein may be combined with other embodiments.

In the description of the embodiments of this application, the term "and/or" is only an association relationship describing associated objects, indicating that there can be three relationships, such as A and/or B, which can mean: A exists alone, and A exists simultaneously and B, there are three cases of B alone. In addition, the character "/" in this article generally indicates that the related objects are an "or" relationship.

In the description of the embodiments of this application, the term "multiple" refers to more than two (including two). Similarly, "multiple groups" refers to two or more groups (including two groups), and "multiple pieces" refers to It is more than two pieces (including two pieces).

In the description of the embodiments of this application, the technical terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "back", "left", "right" and "vertical" The orientation or positional relationships indicated by "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. are based on those shown in the accompanying drawings. The orientation or positional relationship is only for the convenience of describing the embodiments of the present application and simplifying the description. It does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the implementation of the present application. Example limitations.

In the description of the embodiments of this application, unless otherwise clearly stated and limited, technical terms such as "installation", "connection", "connection" and "fixing" should be understood in a broad sense. For example, it can be a fixed connection or a removable connection. It can be disassembled and connected, or integrated; it can also be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be an internal connection between two elements or an interaction between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of this application can be understood according to specific circumstances.

At present, with the development of technology, the application scenarios of power batteries are becoming more and more extensive. Power batteries are not only used in energy storage power systems such as hydraulic, thermal, wind and solar power stations, but also widely used in electric bicycles and electric motorcycles. vehicles, electric vehicles and other electric vehicles, as well as military equipment and aerospace and other fields. As the application fields of power batteries continue to expand, the safety of batteries during use has gradually become the focus of attention.

The applicant has noticed that for secondary batteries with a wound structure, the pole pieces need to be wound during the manufacturing process. During the hot pressing or cold pressing shaping process after winding, it is easy to cause the pole pieces to The lithium precipitation phenomenon caused by inconsistent gaps at the corners affects the normal use of secondary batteries.

Based on the above considerations, in order to solve the problem of lithium precipitation caused by inconsistent gaps between pole pieces in the battery and affecting the normal use of the battery, the applicant has designed a battery cell after in-depth research. The connector assembly is inserted between two adjacent layers of pole pieces in the bent portion of the electrode assembly along the direction of the winding axis of the electrode assembly. Since the connector assembly occupies a certain space in the bent portion, the center of the bent portion can be A certain gap is maintained between two adjacent layers of pole pieces to reduce the risk of lithium precipitation between two adjacent layers of pole pieces and improve the reliability of the battery cells.

The battery cells disclosed in the embodiments of this application are used in batteries. Batteries equipped with the battery cells disclosed in the embodiments of this application are used. Since a certain gap is maintained between two adjacent layers of pole pieces, the energy consumption of the two adjacent layers of poles is reduced. There is no risk of lithium precipitation between chips, and the battery has high reliability.

Embodiments of the present application provide an electrical device that uses a battery as a power source. The electrical device may be, but is not limited to, a mobile phone, a tablet, a laptop, an electric toy, an electric tool, a battery car, an electric vehicle, a ship, a spacecraft, etc. Among them, electric toys can include fixed or mobile electric toys, such as game consoles, electric car toys, electric ship toys, electric airplane toys, etc., and spacecraft can include airplanes, rockets, space shuttles, spaceships, etc.

For the convenience of explanation in the following embodiments, an electrical device 1 in an embodiment of the present application is taken as an example of a vehicle. Please refer to FIG. 1 , which is a schematic diagram of the overall structure of a vehicle provided by an embodiment of the present application.

The vehicle can be a fuel vehicle, a gas vehicle or a new energy vehicle, where the new energy vehicle can be a pure electric vehicle, a hybrid vehicle or an extended-range vehicle, etc. The battery 10 is disposed inside the vehicle, and the battery 10 can be disposed at the bottom, head, or tail of the vehicle. The battery 10 may be used to power a vehicle. For example, the battery 10 may be used as an operating power source for the vehicle. The vehicle may also include a controller and a motor, and the controller is used to control the battery 10 to provide power to the motor, for example, for starting, navigating and driving the vehicle to meet its power requirements. In some embodiments of the present application, the battery 10 can not only be used as the operating power source of the vehicle, but also can be used as the driving power source of the vehicle, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle.

Please refer to FIG. 2 , which is an exploded view of the overall structure of the battery 10 provided by one embodiment of the present application.

The battery 10 composed of battery cells 100 can be used as a power supply system of the electrical device 1 , and several battery cells 100 are arranged in the box 200 . The battery cell 100 refers to the smallest unit that makes up the battery 10. In the battery 10, there can be multiple battery cells 100. The multiple battery cells 100 can be connected in series or in parallel or in a mixed connection. A mixed connection refers to multiple batteries. There are both series and parallel connections in the unit 100. Multiple battery cells 100 can be directly connected in series or in parallel or mixed together to form a battery module, and be accommodated in the box 200 of the battery 10; of course, multiple battery cells 100 can also be connected in series or in parallel or A battery module is formed by mixed connection, and multiple battery modules are connected in series, parallel, or mixed to form a battery module, and are accommodated in the box 200 of the battery 10 .

The box 200 is used to provide an accommodation space for the battery cells 100, and the box 200 can adopt a variety of structures. In some embodiments, the box 200 may include a bottom plate and several side plates. The several side plates are connected end to end with each other. The bottom plate is connected to the bottom of each side plate and together with the side plates, it surrounds a space for accommodating the battery cells 100 . The accommodation space, that is, the bottom plate and the side plates are surrounded to form an accommodation groove. Of course, the receiving groove formed by the bottom plate and the side plate can be in various shapes, such as cylinder, rectangular parallelepiped, etc.

According to some embodiments of the present application, refer to Figures 3 to 5. Figure 3 is a cross-sectional view of the overall structure of the battery cell 100 provided by one embodiment of the present application. Figure 4 is a partial enlarged schematic view of position A in Figure 3. Figure 5 is An embodiment of the present application provides a schematic structural diagram of the plug assembly 120 in the battery cell 100 .

The embodiment of the present application provides a battery cell 100. The battery cell 100 includes an electrode assembly 110 and a plug assembly 120. The electrode assembly 110 includes a straight portion 111 and is disposed on both sides of the straight portion 111 along the first direction a. The bending part 112; the plug component 120 is inserted between two adjacent layers of pole pieces 113 in the bending part 112 on at least one side along the winding axis direction of the electrode assembly 110.

Each battery cell 100 may be a secondary battery or a primary battery, or may be a lithium-sulfur battery, a sodium-ion battery, or a magnesium-ion battery, but is not limited thereto. The battery cell 100 may be in the shape of a cylinder, a flat body, a rectangular parallelepiped or other shapes.

The electrode assembly 110 is formed by rolling the pole piece 113. The electrode assembly 110 includes a straight portion 111 that remains in a straight state, and a bent portion 112 that is bent after being wound. The bent portion 112 is formed along the The first direction a is provided on both sides of the straight portion 111 , and the first direction a can be flexibly set according to the installation requirements of the electrode assembly 110 . For example, the first direction a may be the longitudinal extension direction of the pole piece 113 , that is, after winding the two ends of the pole piece 113 several times along its longitudinal extension direction, the straight portion 111 and the straight portion 111 along the first direction are formed. One direction a is provided on the bent portions 112 on both sides of the straight portion. The number of windings of the electrode assembly 110 is not limited and can be multiple times, and the bending angle of each bending portion 112 is not limited.

Among them, the pole pieces 113 are at least two layers. The at least two layers of pole pieces 113 include a positive electrode piece and a negative electrode piece. The positive electrode piece includes a positive electrode current collector and a positive electrode active material layer coated on the surface of the positive electrode current collector. The negative electrode The pole piece includes a negative electrode current collector and a negative electrode active material layer coated on the surface of the negative electrode current collector.

The pole piece 113 in the electrode assembly 110 has a winding axis (not shown in the figure) during winding. After the pole piece 113 is bent around the winding axis, the bent portion 112 is formed. Therefore, along the winding axis direction, the plug-in component 120 can be inserted unimpeded between two adjacent layers of pole pieces 113 in the bent portion 112. By inserting the plug-in component 120 into the bend along the winding axis direction of the electrode assembly 110, The folded portion 112 facilitates the installation of the plug-in component 120 and helps maintain the gap between the two layers of pole pieces 113 .

The plug assembly 120 is inserted into the bent portion 112 along the winding axis direction of the electrode assembly 110 to occupy a certain space in the bent portion 112, so that a certain gap is maintained between two adjacent layers of pole pieces 113. The specific structure, shape, size, etc. of the connecting component 120 are not limited. Specifically, the plug component 120 is inserted between two adjacent layers of pole pieces 113 in the bent portion 112 .

The plug-in component 120 is inserted into at least one side of the bending portion 112 , that is to say, the plug-in component 120 can be inserted into the bending portion 112 on any side, or it can be inserted into the bending portions on both sides. Plug-in components 120 are inserted into 112 .

In the battery cell 100 of the embodiment of the present application, the plug assembly 120 is inserted between two adjacent layers of pole pieces 113 in the bent portion 112 of the electrode assembly 110 along the winding axis direction of the electrode assembly 110. 120 occupies a certain space in the bent part 112, so that a certain gap can be maintained between two adjacent layers of pole pieces 113 in the bent part 112, preventing the pole pieces 113 from being easily squeezed due to a too small gap and bearing a large load. pressure, reducing the risk of lithium precipitation between two adjacent layers of pole pieces 113, and improving the reliability of the battery cell 100.

In some embodiments, the plug assembly 120 is inserted between two adjacent layers of pole pieces 113 in the bent portion 112 from either side of the winding axis direction of the electrode assembly 110 .

Along the winding axis of the pole pieces 113 in the electrode assembly 110 during winding, the plug assembly 120 can be inserted between two adjacent layers of pole pieces 113 in the bending portion 112 without hindrance. Specifically, the bending The portion 112 has two opposite sides in the direction of the winding axis. The plug-in component 120 can be inserted between two adjacent layers of pole pieces 113 in the bent portion 112 from any side in the direction of the winding axis. In this way The design allows the plug-in component 120 to be plugged in any direction, which facilitates the installation of the plug-in component 120.

Please refer to FIG. 5 in conjunction with FIG. 3 and FIG. 4 . FIG. 5 is a schematic structural diagram of the plug assembly 120 in the battery cell 100 provided by an embodiment of the present application.

In some embodiments, the plug assembly 120 includes a plug connector 121 inserted between two adjacent layers of pole pieces 113 in the bent portion 112 .

That is, the plug component 120 is inserted between two adjacent pole pieces 113 in the bending part 112 through the plug connector 121. The shape, structure, size, etc. of the plug connector 121 are not limited. The required gap size between two adjacent layers of pole pieces 113 can be flexibly adjusted and set. The plug assembly 120 using the plug connector 121 has a simple structure and is easy to process and manufacture.

In one embodiment, there are multiple plug connectors 121 , and each plug connector 121 is inserted between two adjacent layers of pole pieces 113 in the bent portion 112 .

The electrode assembly 110 can be wound multiple times. Therefore, in the bent portion 112 on each side, the pole piece 113 can be wound multiple times to form multiple gaps between two adjacent layers of pole pieces 113. This correspondingly, by arranging multiple plug connectors 121 in the plug assembly 120, they can be respectively inserted between two different adjacent layers of pole pieces 113, so that the distance between the multi-layer pole pieces 113 in the electrode assembly 110 A certain gap is maintained. The specific number of plug connectors 121 can be set according to the number of windings of the pole pieces 113 to ensure that there are plug connectors 121 between each different group of adjacent two layers of pole pieces 113 in the bent portion 112 .

In some embodiments, the plug assembly 120 further includes a fixing base 122 extending along the first direction a. One end of each plug connector 121 protrudes outside the bending portion 112 and is connected to the fixing base 122 .

As shown in FIG. 5 , the plug connector 121 has one end that protrudes outside the bending portion 112 and is connected to the fixing base 122 . Their connection method is not limited. For example, the plug connector 121 can be connected by bonding, The connection with the fixed base 122 is achieved by fastener connection, etc. The plug connector 121 can also be integrally processed and formed with the fixed base 122 . By connecting one end of each plug connector 121 to the fixed base 122 , the position of each plug connector 121 remains fixed relative to the electrode assembly 110 and prevents it from moving in the electrode assembly 110 . In the battery cell 100 , the connector 121 is inserted between two adjacent layers of pole pieces 113 in the bent portion 112 along its end that is not connected to the fixing base 122 , and the fixing base 122 is disposed between the electrode assembly 110 In addition, the normal use of the electrode assembly 110 will not be affected.

In one embodiment, the length of the plug connector 121 protruding out of the bending portion 112 is no more than 5 millimeters (mm).

The length of the plug-in connector 121 protruding out of the bending portion 112 should not be too large or too small. For example, the length of the plug-in connector 121 protruding out of the bending portion 112 can be 1 mm, 2 mm, 2.5 mm, or 4 mm. , 5mm, etc., the above data are only examples. In the actual embodiment, the length of the plug connector 121 protruding out of the bending portion 112 is not limited to the above data. Such a design enables an appropriate gap to be maintained between the fixing base 122 and the electrode assembly 110, which reduces the overall space occupied by the battery cell 100 without affecting the normal use of the electrode assembly 110.

In some embodiments, each plug connector 121 is arranged side by side along the first direction a on the fixed base 122, and two adjacent plug connectors 121 are spaced apart from each other.

Please continue to refer to FIG. 5 . A plurality of plug connectors 121 are arranged side by side on the fixed base 122 along the first direction a. When the plug connectors 121 are inserted between two adjacent layers of pole pieces 113 in the bending portion 112 , Facilitates the installation of the plug assembly 120. By arranging the plug connectors 121 side by side and spaced apart from each other along the first direction a on the fixed base 122 , that is, the arrangement direction of the plug connectors 121 is parallel to the arrangement direction of the bending portion 112 . In this way, the plug connectors 121 It can be evenly inserted into the bent portion 112 to make the gaps between the pole pieces 113 in the bent portion 112 more uniform.

Please refer to Figure 6 to Figure 7 in conjunction with Figure 5. Figure 6 is a schematic structural diagram of the plug assembly 120 in the battery cell 100 provided by another embodiment of the present application. Figure 7 is a battery cell provided by another embodiment of the present application. A schematic structural diagram of the plug assembly 120 in 100.

In some embodiments, along the longitudinal extension direction of the plug connector 121, the projected outline of the plug connector 121 on the surface of the fixing base 122 is circular, linear, folded or arc-shaped.

As shown in FIG. 5 , in this embodiment, along the longitudinal extension direction of the plug connector 121 , the projected outline of the plug connector 121 on the surface of the fixing base 122 is circular. In this way, the plug connector 121 has a simple structure and a smooth cross-section. The size is uniform, which facilitates the installation of the plug connector 121.

As shown in FIG. 6 , in this embodiment, along the longitudinal extension direction of the plug connector 121 , the projected outline of the plug connector 121 on the surface of the fixing base 122 is linear. This structure can increase the strength of the plug connector 121 . The maximum cross-sectional size is suitable for electrode assemblies 110 that require a larger gap between two adjacent layers of pole pieces 113 .

As shown in FIG. 7 , along the longitudinal extension direction of the plug connector 121 , the projected outline of the plug connector 121 on the surface of the fixing base 122 is a polygonal shape. In this way, the cross section of the plug connector 121 has different sizes at different positions, and from the size There is a uniform transition from the largest part to the smallest part, which is beneficial to the uniformity of the gap between two adjacent layers of pole pieces 113.

Of course, the above shapes are only examples. In actual embodiments, the projected outline of the plug connector 121 on the surface of the fixing base 122 is not limited to the above shape, and may also be an arc shape or other shapes. By arranging plug connectors 121 of different shapes, the position of the plug connector 121 between two adjacent pole pieces 113 in the bent portion 112 can be adjusted without changing the distance between the two adjacent plug connectors 121 . The size of the space occupied in the gap between them, that is, adjusting the gap between two adjacent layers of pole pieces 113, can be adapted to different usage requirements.

In some embodiments, the plug connector 121 is provided with multiple liquid storage holes (not shown in the figure).

The liquid storage hole can be used to store electrolyte. The electrolyte is a medium required for the battery cell 100 to work normally. The electrolyte can provide ions for electrochemical reactions and ensure that the chemical reactions that occur during operation are reversible. . The liquid storage hole on the plug connector 121 can absorb and store the electrolyte through capillary phenomenon, so that the electrolyte can diffuse between the two adjacent layers of pole pieces 113 with the help of the plug connector 121, ensuring that the bent portion 112 can be electrolyzed The liquid wetting further reduces the risk of lithium precipitation in the electrode assembly 110 .

In some embodiments, the liquid storage holes include through holes and/or blind holes.

A through hole refers to a liquid storage hole with both ends opening through the connector 121, while a blind hole refers to a liquid storage hole with only one end opening penetrating through the connector 121 and the other end opening buried in the connector 121. Providing through holes on the plug connector 121 can be used as a storage space and transmission channel for the electrolyte, and providing blind holes can be used as a storage space for the electrolyte, so that the plug connector 121 can absorb the electrolyte to wet the bent portion 112 . The liquid storage hole on the connector 121 can be flexibly set according to actual use requirements. It can be provided with only through holes, only blind holes, or both through holes and blind holes.

In some embodiments, the diameter of the liquid storage hole is greater than or equal to 1 micrometer (μm) and less than or equal to 10 micrometer (μm).

The diameter of the liquid storage hole can be flexibly set. For example, the diameter of the liquid storage hole can be 1 μm or 2 μm.

μm, 4.5 μm, 7 μm, 8.5 μm, 10 μm, etc., the above data are only examples, and in actual embodiments, the diameter of the liquid storage hole is not limited to the above data. Properly setting the diameter of the liquid storage hole not only facilitates the arrangement of the liquid storage hole, but also enables the plug connector 121 to absorb enough electrolyte to ensure the wetting effect on the bent portion 112 .

In one embodiment, the porosity of the plug connector 121 is greater than or equal to 30% and less than or equal to 50%.

Porosity refers to the percentage of the pore volume of the liquid storage hole in the connector 121 to the total volume of the connector 121 material in its natural state. Another concept corresponding to the porosity is the compactness. The compactness represents the connector 121 The degree to which the interior is filled with solids quantitatively reflects the content of solids inside the connector 121, and its impact on material properties is exactly opposite to the impact of porosity. All in all, the porosity or density directly reflects the density of the connector 121. A high porosity of the connector 121 indicates a low density. On the contrary, a low porosity of the connector 121 indicates a large density. The porosity of the connector 121 can be 30%, 35%, 42%, 48%, 50%, etc. The above data are only examples. In actual embodiments, the porosity of the connector 121 is not limited to the above data. . Properly setting the porosity of the connector 121 not only facilitates the processing of the connector 121 , but also enables the connector 121 to absorb enough electrolyte to ensure the wetting effect on the bent portion 112 .

In some embodiments, the connector 121 is made of polyethylene or polypropylene.

Polyethylene (PE, polyethylene) is made from the polymerization of ethylene. It has excellent low temperature resistance, good chemical stability, and can resist the erosion of most acids and alkalis. Polypropylene (PP, polypropylene) is produced from propylene through the addition polymerization reaction and has chemical resistance, heat resistance, electrical insulation, high strength mechanical properties and good high wear resistance processing properties. Such a design enables the connector 121 to have excellent physical and chemical properties, is easy to process and manufacture, and has low cost.

In some embodiments, a diaphragm 114 is provided between two adjacent layers of pole pieces 113 in the bent portion 112 , and the plug-in component 120 is inserted between the pole pieces 113 and the diaphragm 114 .

Please continue to refer to Figures 3 to 4. In order to prevent short circuits between two adjacent layers of pole pieces 113, the electrode assembly 110 also includes a separator 114. The separator 114 is made of insulating material, and the two adjacent layers of pole pieces 113 are arranged opposite to each other. , the diaphragm 114 can be disposed between two adjacent layers of pole pieces 113 to insulate them. At this time, there is a gap between the pole piece 113 and the diaphragm 114 in the bent portion 112 , and the plug-in component 120 can be inserted between the pole piece 113 and the diaphragm 114 . By inserting the plug assembly 120 between the pole piece 113 and the separator 114 in the bent portion 112, a certain gap is maintained between the pole piece 113 and the separator 114, thereby reducing the risk of lithium deposition in the pole piece 113 and improving battery performance. The reliability of the single unit 100.

In one embodiment, the plug component 120 is attached to the side of its corresponding pole piece 113 facing the bending center of the bending portion 112 .

As shown in FIGS. 3 and 4 , the bending portion 112 has a bending center after being bent, and the bending center is the center of the arc where the bending portion 112 is located. At the same time, the bending portion 112 has a bending center toward the bending center. one side, and a side away from the bending center, wherein the bending portion 112 is concave on the side facing the bending center, and the bending portion 112 is convex on the side away from the bending center. After the plug-in component 120 is inserted between the pole piece 113 and the diaphragm 114, the two sides of the plug-in assembly 120 are respectively the corresponding pole piece 113 and the diaphragm 114. The plug-in assembly 120 can be attached to its corresponding on the pole piece 113, and the plug-in component 120 is attached to the side of the corresponding pole piece 113 facing the bending center of the bending part 112, so that the plug-in component 120 is in contact with the recess of the pole piece 113 in the bending part 112 The contact points avoid stress concentration on the pole piece 113 in the bent portion 112 , reduce the risk of lithium precipitation in the pole piece 113 , and improve the reliability of the battery cell 100 .

According to another aspect of the present application, an embodiment of the present application also provides a battery 10. The battery 10 includes a box 200 and a plurality of battery cells 100 as described above. The battery cells 100 are accommodated in the box 200.

The battery 10 in the embodiment of the present application adopts the above-mentioned battery cell 100, and inserts the plug assembly 120 between two adjacent layers of pole pieces 113 in the bent portion 112 of the electrode assembly 110 along the winding axis direction of the electrode assembly 110. time, since the plug-in component 120 occupies a certain space in the bending part 112, a certain gap can be maintained between two adjacent layers of pole pieces 113 in the bending part 112, and the gap between two adjacent layers of pole pieces 113 can be reduced. The risk of lithium precipitation occurs and the reliability of the battery cell 100 is improved.

According to another aspect of the present application, an embodiment of the present application also provides an electrical device 1. The electrical device 1 includes the above-mentioned battery 10, and the battery 10 is used to provide electrical energy.

The electric device 1 in the embodiment of the present application uses the above-mentioned battery 10 to provide electric energy. Since the battery 10 has high reliability, the safety of the electric device 1 is also higher.

Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present application, but not to limit it; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: The technical solutions described in the foregoing embodiments can still be modified, or some or all of the technical features can be equivalently replaced; and these modifications or substitutions do not deviate from the essence of the corresponding technical solutions from the technical solutions of the embodiments of the present application. The scope shall be covered by the claims and description of this application. In particular, as long as there is no structural conflict, the technical features mentioned in the various embodiments can be combined in any way. The application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

A battery cell including:

An electrode assembly, the electrode assembly includes a straight portion and bent portions provided on both sides of the straight portion along a first direction; and

The plug-in component is inserted between two adjacent layers of pole pieces in the bent portion on at least one side along the winding axis direction of the electrode assembly.
The battery cell according to claim 1, wherein the plug-in assembly includes a plurality of plug-in connectors, and each of the plug-in connectors is inserted between two adjacent layers of pole pieces in the bent portion.
The battery cell according to claim 2, wherein the plug-in assembly further includes a fixing base, the fixing base extends along the first direction, and one end of each plug-in connector protrudes to the bend. external and connected to the fixed base.
The battery cell according to claim 3, wherein the length of the plug connector protruding out of the bending portion is no more than 5 mm.
The battery cell according to claim 3, wherein each of the plug connectors is arranged side by side on the fixing base along the first direction, and two adjacent plug connectors are spaced apart from each other.
The battery cell according to claim 3, wherein along the longitudinal extension direction of the plug connector, the projected outline of the plug connector on the surface of the holder is circular, linear, broken line or arc. linear.
The battery cell according to any one of claims 2 to 6, wherein the connector is provided with a plurality of liquid storage holes.
The battery cell according to claim 7, wherein the liquid storage hole includes a through hole and/or a blind hole.
The battery cell according to claim 7, wherein the diameter of the liquid storage hole is 1 μm or more and 10 μm or less.
The battery cell according to claim 7, wherein the porosity of the plug connector is 30% or more and 50% or less.
The battery cell according to any one of claims 2 to 6, wherein the connector is made of polyethylene or polypropylene.
The battery cell according to any one of claims 1 to 6, wherein a separator is provided between two adjacent pole pieces in the bent portion, and the plug-in component is inserted between the pole piece and the pole piece. between the diaphragms.
The battery cell according to claim 12, wherein the plug component is attached to a side of the corresponding pole piece facing the bending center of the bending portion.
A battery including:

box; and

A plurality of battery cells according to any one of claims 1 to 13, said battery cells being accommodated in said box.
An electrical device including:

The battery of claim 14, said battery being used to provide electrical energy.