Winding battery cell, battery monomer, battery device and electric equipment

Abstract

The invention discloses a winding battery cell, a battery monomer, a battery device and electric equipment, and relates to the technical field of batteries, the battery monomer comprises a shell and a winding battery cell, and the shell is provided with a mounting cavity; the winding battery cell is arranged in the mounting cavity and comprises a flat winding body formed by winding a diaphragm, a first pole piece and a second pole piece which are stacked in sequence, and the first pole piece and the second pole piece are opposite in polarity; the starting end of the first pole piece and / or the starting end of the second pole piece in the flat winding body are / is connected with a solid cylinder structure, the solid cylinder structure is formed by winding the first composite pole piece and / or the second composite pole piece, and the cross section of the flat winding body is provided with two spaced focuses; the solid cylinder structure is located at the position where at least one focus is located. According to the battery monomer, the risk of cracking of the hot-pressed inner ring of the battery cell can be reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of batteries, and in particular to a wound battery core, a battery cell, a battery device and electrical equipment. Background Art

[0002] In the production process of battery cells, after the pole piece winding process, the hot pressing process of the battery cell is usually carried out to compact the battery cell to increase the energy density of the battery. Due to the characteristics of the wound pole piece, the stress is concentrated at the inner corner after hot pressing, and the pole piece is prone to cracking and powder falling in the inner corner area, which reduces the battery performance and affects the battery life. Summary of the invention

[0003] The main purpose of the present invention is to provide a battery cell, aiming to solve the technical problem that the inner circle of the pole piece in the battery cell is prone to cracking and powdering.

[0004] To achieve the above-mentioned purpose, the battery cell proposed by the present invention comprises: a housing having a mounting cavity; and A wound battery cell, the wound battery cell is arranged in the installation cavity, and the wound battery cell comprises a flat wound body formed by winding a diaphragm stacked in sequence, a first pole piece and a second pole piece with opposite polarities; The starting end of the first pole piece and / or the starting end of the second pole piece in the flat winding body are connected to a solid cylindrical structure, and the solid cylindrical structure is formed by winding the first composite pole piece and / or the second composite pole piece. The cross-section of the flat winding body has two intervals of focal points, and the solid cylindrical structure is located at the position of at least one of the focal points.

[0005] In this example, the flat winding body, also known as the racetrack-type battery cell, has a gap at least at the corner position of its inner circle. The starting end of the first pole piece and / or the starting end of the second pole piece in the flat winding body refers to the end where the winding starts, and a solid column structure is connected here, that is, a solid column structure is provided at the gap position in the inner circle of the flat winding body. The solid structural stability of the solid column structure is used to provide support and buffer for the inner circle of the flat winding body, thereby reducing the situation where the inner circle of the wound battery cell breaks or loses powder after hot pressing or expansion. At the same time, the solid column structure is formed by winding the first composite pole piece, or by winding the second composite pole piece, or by winding the first composite pole piece and the second composite pole piece together, without adding any additional structures, saving processes, and being able to increase energy density and improve battery cell performance.

[0006] The focal position of the flat winding body is close to the corner position of the inner circle, so arranging the solid column structure at the position of at least one focal point can provide better support and prevent the inner circle corner position of the flat winding body from breaking or falling off.

[0007] In one embodiment of the present invention, the cross section of the solid column structure is circular.

[0008] The circular solid cylindrical structure can better match the inner ring shape of the flat winding body, further improving the support and cushioning of each position, providing space for the inner ring to break or the active material to fall off, and making short circuit less likely to occur.

[0009] In one embodiment of the present invention, the outer diameter of the solid cylindrical structure is the same as the inner diameter of the corner of the flat wound body, and the outer side of the solid cylindrical structure is in contact with the inner surface of the corner of the flat wound body.

[0010] The continuity of the solid cylindrical structure and the flat winding body can be achieved through complete bonding, and the lithium insertion and removal of the electrode can be completed.

[0011] In one embodiment of the present invention, the first composite pole piece includes the first pole piece, and the solid cylindrical structure is formed by winding the first pole piece; Alternatively, the first composite pole piece includes the first pole piece and the diaphragm, and the solid column structure is formed by stacking and winding the diaphragm, the first pole piece and the diaphragm in sequence.

[0012] The first composite pole piece may be a single first pole piece material or a composite structure of the first pole piece and a diaphragm. The solid cylindrical structure is formed by winding the first composite pole piece alone, which can further facilitate processing and improve structural strength and stability.

[0013] In one embodiment of the present invention, the second composite pole piece includes the second pole piece, and the solid cylindrical structure is formed by winding the second pole piece; Alternatively, the second composite pole piece includes the second pole piece and the diaphragm, and the solid column structure is formed by stacking and winding the diaphragm, the second pole piece and the diaphragm in sequence.

[0014] The second composite pole piece may be a single second pole piece material or a composite structure of a second pole piece and a diaphragm. The solid cylindrical structure is formed by winding the second composite pole piece alone, which can further facilitate processing and improve structural strength and stability.

[0015] In one embodiment of the present invention, the first composite pole piece includes the first pole piece and the diaphragm, the second composite pole piece includes the second pole piece and the diaphragm, and the solid column structure is formed by winding the diaphragm, the first pole piece, the diaphragm, the second pole piece and the diaphragm in sequence.

[0016] The solid cylindrical structure is formed by winding the first composite pole piece and the second composite pole piece, which can improve the energy density while providing inner ring support.

[0017] In one embodiment of the present invention, one of the focal points is provided with the solid cylindrical structure and is set as a first solid cylindrical structure, the first pole piece of the first solid cylindrical structure is connected to the starting end of the first pole piece in the flat winding body, and the second pole piece of the first solid cylindrical structure is connected to the starting end of the second pole piece of the flat winding body.

[0018] In this example, the first solid cylindrical structure is directly wound according to the original winding method, and then the flat winding body on the outside is wound. On the basis of providing inner circle support, the process is simplified and the processing efficiency is improved.

[0019] In one embodiment of the present invention, the solid cylindrical structure is provided at both focal points and is set as a second solid cylindrical structure, wherein a first pole piece of the second solid cylindrical structure is connected to a starting end of a first pole piece in the flat winding body; and a second pole piece of the other second solid cylindrical structure is connected to a starting end of a second pole piece in the flat winding body.

[0020] In this example, a second solid column structure is provided at both focal points, which can further enhance the support stability of the inner circle of the flat winding body, and can also increase the energy density of the battery cell through the second solid column structure.

[0021] In one embodiment of the present invention, the solid cylindrical structure is provided at both focal points and is set as a third solid cylindrical structure, wherein one of the third solid cylindrical structures is wound by the first composite pole piece and is connected to the starting end of the first pole piece in the flat winding body; The other third solid cylindrical structure is wound by the second composite pole piece and is connected to the starting end of the second pole piece in the flat winding body.

[0022] In this example, a third solid column structure is provided at both focal points to enhance the support stability of the inner ring of the flat winding body and facilitate the simultaneous forming of two third solid column structures.

[0023] In an embodiment of the present invention, the winding number M of the solid cylindrical structure is greater than or equal to 3 and less than or equal to 10.

[0024] The number of winding turns of the solid cylindrical structure can improve the support stability without affecting the overall volume of the battery cell.

[0025] In one embodiment of the present invention, the ratio of the number of windings M of the solid cylindrical structure to the number of windings N of the flat winding body is greater than or equal to 1 / 10 and less than or equal to 1 / 4.

[0026] In this structure, the number of turns of the solid column structure is matched with the number of turns of the flat winding body, so that the overall volume can be reduced while satisfying the supporting function.

[0027] In one embodiment of the present invention, a first pole lug is disposed at one end of the solid cylindrical structure, and a second pole lug is disposed at the flat winding body, and the first pole lug is connected to the second pole lug.

[0028] This structure can further improve the structural stability of the overall wound battery cell.

[0029] In one embodiment of the present invention, the outermost pole piece of the flat winding body is a first pole piece, and the first pole piece is an anode pole piece.

[0030] The outer ring pole piece is set as the anode pole piece to improve the performance of the battery cell.

[0031] The present invention further provides a wound battery core, the wound battery core comprising a flat wound body formed by sequentially stacking a separator, a first pole piece and a second pole piece with opposite polarities wound along a virtual axis; The starting end of the first pole piece and / or the starting end of the second pole piece in the flat winding body are connected with a solid column structure, and the solid column structure is formed by winding the first composite pole piece and / or the second composite pole piece.

[0032] The flat winding body is also called a racetrack-type battery cell, and there is a gap at least at the corner position of the inner circle. The starting end of the first pole piece and / or the starting end of the second pole piece in the flat winding body refers to the end where the winding starts, and a solid column structure is connected here, that is, a solid column structure is provided at the gap position in the inner circle of the flat winding body, and the solid structure stability of the solid column structure is used to provide support and buffer for the inner circle of the flat winding body, thereby reducing the situation where the inner circle of the wound battery cell breaks or loses powder after hot pressing or expansion. At the same time, the solid column structure is wound by the first composite pole piece, or by the second composite pole piece, or by the first composite pole piece and the second composite pole piece. There is no need to add other additional structures, which saves processes, and can increase energy density and improve battery cell performance.

[0033] The present invention further provides a battery device, comprising any of the battery cells described above.

[0034] The present invention also provides an electrical device, comprising the battery device as described above. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0036] Figure 1 It is a structural schematic diagram of the electrical equipment of the present invention; Figure 2 A partial exploded view of the battery device of the present invention; Figure 3 It is a structural schematic diagram of a first embodiment of a wound battery cell of the present invention; Figure 4 It is a structural schematic diagram of a second embodiment of a wound battery cell of the present invention; Figure 5 It is a schematic structural diagram of a third embodiment of a wound battery cell of the present invention.

[0037] Description of Figure Numbers: 100, battery device; 10, housing; 11, first part; 12, second part; 20, battery cell; 21, wound battery cell; 211, flat wound body; 2111, first pole piece; 2112, second pole piece; 2113, diaphragm; 212a, first solid cylindrical structure; 212b, second solid cylindrical structure; 212c, third solid cylindrical structure; 200, controller; 300, motor.

[0038] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0039] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0040] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0041] In the present invention, unless otherwise clearly specified and limited, the terms "connection", "fixation", etc. should be understood in a broad sense. For example, "fixation" 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, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0042] In addition, the descriptions of "first", "second", etc. in the present invention are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the meaning of "and / or" appearing in the full text is to include three parallel solutions. Taking "A and / or B as an example", it includes solution A, or solution B, or a solution that satisfies both A and B. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in this field to implement. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0043] The battery devices mentioned in the art can be divided into disposable batteries and rechargeable batteries according to whether they are rechargeable. The common types of rechargeable batteries currently include: lead-acid batteries, nickel-metal hydride batteries and lithium-ion batteries. The battery device described in the embodiments of the present invention refers to a rechargeable battery. The embodiments disclosed in the present invention will be described below mainly using lithium-ion batteries as an example. It should be understood that the embodiments disclosed in the present invention are applicable to any other appropriate type of rechargeable battery. The battery device mentioned in the embodiments disclosed in the present invention can be directly or indirectly applied to an appropriate device to power the device.

[0044] The battery device mentioned in the embodiments disclosed in the present invention refers to a single physical module including one or more battery cells to provide a predetermined voltage and capacity, which can be a battery module or a battery pack. The battery cell is the basic unit in the battery device, which can be used to make a battery module or a battery pack. The battery module is formed by connecting a certain number of battery cells in series and / or in parallel and placing them in a frame in order to protect the battery cells from external impact, heat, vibration, etc. The battery pack generally includes a battery module, a battery management system, and a box that accommodates the battery module and the battery management system. The battery management system is used to monitor and manage the charging and discharging process of the battery module.

[0045] The battery cell is an important component of the battery monomer. According to the preparation method of the battery cell, it can be divided into a wound battery cell and a laminated battery cell. Among them, the wound battery cell is widely used because it is relatively simple to operate and the quality is easy to control. The wound battery cell generally includes a negative electrode sheet, a positive electrode sheet and a separator arranged and wound in a preset order. The positive electrode sheet and the negative electrode sheet are generally composed of a current collector and an active material layer coated on the current collector, respectively. The wound battery cell can be a square structure or a cylindrical structure. Among them, the square wound battery cell is widely used due to its advantages such as good heat dissipation.

[0046] In the production process of wound cells, a hot pressing process is usually performed after the winding process of the cell, so as to compact the cell and increase the energy density of the battery cell. For wound cells, due to the presence of the winding needle, after the positive electrode sheet, the separator, and the negative electrode sheet are wound, gaps will be formed in at least part of the inner circle of the cell. There are corners in the inner circle, and the pressure of hot pressing is high. After hot pressing, stress is concentrated at the corners of the inner circle, which is prone to cracking, powder loss, and other problems. If the battery cell loses powder, breaks, or exposes the substrate during use, it will cause the battery performance to decline, and even short circuit risks, which will affect the service life of the battery.

[0047] Based on the above background, the present invention proposes a battery cell. By improving the wound cell of the battery cell, a solid cylindrical structure is set at the inner circle of the flat winding body to provide support and buffering for the inner circle electrode sheet of the flat winding body, thereby reducing the risk of breakage or powder loss of the inner circle electrode sheet.

[0048] The battery device disclosed in the embodiment of the present application can be used in various energy storage systems that use batteries as power sources or use batteries as energy storage elements. The electrical equipment can be, but is not limited to, mobile phones, tablets, laptops, electric toys, electric tools, battery cars, electric cars, ships, spacecraft, etc. Among them, electric toys can include fixed or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc., and spacecraft can include airplanes, rockets, space shuttles, and spacecraft, etc.

[0049] For the convenience of explanation, the following examples are referred to Figure 1 , an electrical device in one embodiment of the present application is taken as an example of a vehicle.

[0050] Figure 1The electrical equipment provided for some embodiments of the present application is a schematic diagram of the structure of a vehicle. The vehicle 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, and the battery device 100 may be provided at the bottom, head or tail of the vehicle. The battery device 100 may be used to power the vehicle, for example, the battery device 100 may be used as an operating power source for the vehicle. The vehicle 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.

[0051] In some embodiments of the present application, the battery device 100 can be used not only as an operating power source for the vehicle, but also as a driving power source for the vehicle, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle.

[0052] refer to Figure 2 , Figure 2 An exploded view of a battery device 100 provided in some embodiments of the present application. The battery device 100 includes a box 10 and at least two battery cells 20, wherein the box 10 is used to provide a storage space for the battery cells 20, and the box 10 can adopt a variety of structures. In some embodiments, the box 10 may include a first part 11 and a second part 12, the first part 11 and the second part 12 cover each other, and the first part 11 and the second part 12 jointly define a storage space. The second part 12 may be a hollow structure with one end open, the first part 11 may be a plate-like structure, and the first part 11 covers the open side of the second part 12, so that the first part 11 and the second part 12 jointly define a storage space; the first part 11 and the second part 12 may also be hollow structures with one side open, and the open side of the first part 11 covers the open side of the second part 12. Of course, the box 10 formed by the first part 11 and the second part 12 may be in a variety of shapes, such as a cylinder, a cuboid, etc.

[0053] In the battery device 100, there may be a plurality of battery cells 20, which may be connected in series, in parallel, or in mixed series to form a whole and accommodated in the box 10. Mixed series means that the plurality of battery cells 20 are both connected in series and in parallel. The battery device 100 may also include other structures, for example, a busbar component for realizing electrical connection between the plurality of battery cells 20.

[0054] The battery cell 20 may be a secondary battery or a primary battery, or a lithium-sulfur battery, a sodium-ion battery, or a magnesium-ion battery, etc. The battery cell 20 may be cylindrical, flat, rectangular, or in other shapes.

[0055] In some cases, the battery cell 20 can also be directly installed in the vehicle without the box body 10 or the shell, that is, there is no need to form a battery pack, and the structure of the vehicle body itself serves as the fixing structure of the battery cell 20.

[0056] The battery cell 20 of the present application is introduced below with a specific embodiment: Please refer to Figures 3 to 5 In one embodiment of the present invention, the battery cell 20 includes: a housing having a mounting cavity; and A wound battery cell 21, wherein the wound battery cell 21 is disposed in the mounting cavity, and the wound battery cell 21 comprises a flat wound body 211 formed by winding a diaphragm stacked in sequence, a first pole piece 2111 and a second pole piece 2112 with opposite polarities; The starting end of the first pole piece 2111 and / or the starting end of the second pole piece 2112 in the flat winding body 211 are connected to a solid cylindrical structure, and the solid cylindrical structure is formed by winding the first composite pole piece and / or the second composite pole piece. The cross-section of the flat winding body 211 has two separated focal points, and the solid cylindrical structure is located at the position of at least one of the focal points.

[0057] In this embodiment, the battery cell 20 includes a shell and a wound battery cell 21. The shell is a closed structure and is provided with a mounting cavity required for the battery cell. The shell generally includes an end cover and a shell body. The shell body is formed with a receiving groove with an opening. The battery cell is installed in the receiving groove, and the end cover is covered with the opening to form a mounting cavity. The specific structure of the end cover and other functional components provided thereon can refer to the existing end cover structure, which will not be described in detail here. Of course, electrolyte and other components are also provided in the shell, which will not be described in detail here.

[0058] One, two or more wound cells 21 may be provided in a battery cell 20. The wound cell 21 is formed by stacking and winding a separator, a first pole piece 2111 and a second pole piece 2112 in a preset order, and is generally stacked in the order of separator, first pole piece 2111, separator, second pole piece 2112, separator, or separator, second pole piece 2112, separator, first pole piece 2111, separator. The first pole piece 2111 may be an anode pole piece, and the second pole piece 2112 may be a cathode pole piece, or the second pole piece 2112 may be an anode pole piece and the first pole piece 2111 may be a cathode pole piece, which is not limited here.

[0059] In this example, the first pole piece 2111, the second pole piece 2112 and the diaphragm are stacked and wound in a preset order, and then hot-pressed to form a flat winding body 211, which is a winding structure similar to a runway. Among them, the pole piece of the innermost circle is composed of two sheets fitted together, and then wound with the support of a winding needle. The pole piece part of each remaining circle includes two oppositely arranged straight portions and two corner portions connecting the two straight portions. The starting end of the innermost circle pole piece can correspond to the position of the straight portion, or it can be located at the position of the corner portion, which is not limited here.

[0060] When the starting end of the pole piece is located at the position corresponding to the straight part, there will be a gap between the starting end and the second corner of the pole piece, and there will also be a gap between the starting end and the straight part after the pole piece is wound around the first corner due to the existence of the corner. If the starting end of the innermost pole piece corresponds to the corner position, there will be gaps at the corner where the starting end of the pole piece is located and at the second corner of the pole piece.

[0061] A solid columnar structure refers to a columnar structure that is technologically feasible and has no internal voids, and has high structural strength and hardness. The extension direction of the columnar structure is the same as the height direction of the flat winding body 211. The height of the columnar structure is not limited here, and can be the same as the height of the flat winding body 211, and can provide support at various positions of the flat winding body 211 in the height direction. In other examples, the height of the columnar structure can also be less than the height of the flat winding body 211. A solid columnar structure is connected to the starting end of the first pole piece 2111, and / or a solid columnar structure is connected to the starting end of the second pole piece 2112. The solid columnar structure can be located in the gap at the corner portion, thereby supporting the two corner portions. In other examples, the solid columnar structure can also be located in the gap between the two straight portions of the innermost circle. The connection between the solid columnar structure and the first pole piece 2111 and / or the second pole piece 2112 can be a connection of the current collector of the pole piece, or a connection of the pole ear, which is not limited here.

[0062] The solid column structure is formed by winding the first composite pole piece, which means that the solid column structure is formed by winding the material including the first pole piece 2111 to form a solid column structure, for example, only including the first pole piece 2111, or including the first pole piece 2111 and the diaphragm, or may also include other structures that enhance the performance of the pole piece. Or, the solid column structure is formed by winding the second composite pole piece, which means that the solid column structure is formed by winding the material including the second pole piece 2112 to form a solid column structure, for example, the second pole piece 2112, or the second pole piece 2112 and the diaphragm, or may also include other structures that enhance the performance of the pole piece. Or, the solid column structure is formed by stacking and winding the first pole piece 2111, the diaphragm, and the second pole piece 2112 in sequence. The cross-sectional shape of the solid column structure may be circular, square, polygonal, etc., which is not limited here.

[0063] In this example, the flat winding body 211 is also a racetrack-type battery cell. The starting end of the first pole piece 2111 and / or the starting end of the second pole piece 2112 in the flat winding body 211 refers to the end where the winding starts, and a solid cylindrical structure is connected here, that is, a solid cylindrical structure is provided in the hollow position of the inner circle of the flat winding body 211. The solid structural stability of the solid cylindrical structure is used to provide support and buffer for the inner circle of the flat winding body 211, thereby reducing the situation where the inner circle of the wound battery cell 21 breaks or loses powder after hot pressing or expansion. At the same time, the solid cylindrical structure is wound by the first composite pole piece, or by the second composite pole piece, or by the first composite pole piece and the second composite pole piece. There is no need to add other additional structures, which saves processes, and can increase energy density and improve the performance of the battery cell 20.

[0064] In this example, the cross section of the flat winding body 211 refers to the surface formed by cutting the flat winding body 211 with a plane perpendicular to the winding axis direction. The cross section is a special ellipse, that is, the two corners of the flat winding body 211 are semicircular, and the centers of the two corners are the two foci spaced apart. The solid cylindrical structure is located at the position where the foci are located, and it can be that one solid cylindrical structure is set at one of the foci, or two solid cylindrical structures are set at the two foci respectively. In other examples, the solid cylindrical structure can also be set at a position between the two foci.

[0065] During hot pressing, the stress on the corners of the flat wound body 211 is most concentrated, and the focal position of the flat wound body 211 is close to the corner position of the inner circle. Therefore, setting the solid cylindrical structure at the focal position can provide better support and prevent the inner circle corner position of the flat wound body 211 from breaking or falling off.

[0066] Please continue to refer to Figure 4In one embodiment of the present invention, the cross-section of the solid column structure is circular.

[0067] In this example, the cross section of the solid cylindrical structure refers to the surface after the solid cylindrical structure is cut by a plane perpendicular to the axial direction of the cylinder. In other examples, the cross section of the solid cylindrical structure may also be an ellipse or the like.

[0068] The shape of the corner of the inner circle of the flat winding body 211 is semicircular, so the circular solid column structure can better match the shape of the inner circle of the flat winding body 211, further enhancing the support and cushioning of each position, providing space for the inner circle to break or the active material to fall off, and preventing short circuit from occurring.

[0069] In one embodiment of the present invention, the outer diameter of the solid cylindrical structure is the same as the inner diameter of the corner of the flat wound body 211 , and the outer side of the solid cylindrical structure is attached to the inner surface of the corner of the flat wound body 211 .

[0070] In this example, the solid cylindrical structure is wound to form a cylinder, and the cross-section of the corner of the inner circle of the flat winding body 211 is semicircular. The outer diameter of the solid cylindrical structure is set to be the same as the inner diameter of the corner of the flat winding body 211. When winding the flat winding body 211, the solid cylindrical structure can be used as a winding needle to make the outer side of the solid cylindrical structure fit the inner surface of the corner of the flat winding body 211. In other examples, the solid cylindrical structure and the flat winding body 211 can be processed separately, and then the solid cylindrical structure is placed in the inner circle of the flat winding body 211 for connection and fixation and then hot pressing. The pole piece on the outside of the solid cylindrical structure is opposite to the pole piece at the corner of the inner circle of the flat winding body 211, thereby achieving charging and discharging.

[0071] The wound battery cell 21 of this structure can provide a firm support for the flat wound body 211 by completely fitting the solid cylindrical structure and the flat wound body 211 , and can also achieve complete lithium extraction from the pole pieces by fitting the pole pieces with opposite polarities, further improving the energy density.

[0072] In one embodiment of the present invention, the first composite pole piece includes the first pole piece 2111, and the solid cylindrical structure is formed by winding the first pole piece 2111; Alternatively, the first composite pole piece includes the first pole piece 2111 and the diaphragm, and the solid column structure is formed by stacking and winding the diaphragm, the first pole piece 2111 and the diaphragm in sequence.

[0073] In one example, the first composite pole piece may be a separate first pole piece 2111, and the solid cylindrical structure is formed by winding only the first pole piece 2111, which can further facilitate processing. In another example, the first composite pole piece is a composite structure consisting of the first pole piece 2111 and a diaphragm, and the solid cylindrical structure is formed by winding the first composite pole piece, which can further facilitate processing and improve structural strength and stability.

[0074] In one embodiment of the present invention, the second composite pole piece includes the second pole piece 2112, and the solid cylindrical structure is formed by winding the second pole piece 2112; Alternatively, the second composite pole piece includes the second pole piece 2112 and the diaphragm, and the solid column structure is formed by stacking and winding the diaphragm, the second pole piece 2112 and the diaphragm in sequence.

[0075] In one example, the second composite pole piece may be a separate second pole piece 2112, and the solid cylindrical structure is formed by winding only the second pole piece 2112, which can further facilitate processing. In another example, the second composite pole piece may also be a composite structure consisting of the second pole piece 2112 and a diaphragm, and the solid cylindrical structure is formed by winding the second composite pole piece, which can further facilitate processing and improve structural strength and stability.

[0076] In one embodiment of the present invention, the first composite pole piece includes the first pole piece 2111 and the diaphragm, the second composite pole piece includes the second pole piece 2112 and the diaphragm, and the solid column structure is formed by winding the diaphragm, the first pole piece 2111, the diaphragm, the second pole piece 2112 and the diaphragm in sequence.

[0077] In this example, the solid cylindrical structure is formed by winding the first composite pole piece and the second composite pole piece together, so that lithium can be inserted and removed inside the solid cylindrical structure, thereby improving the energy density of the battery cell 20 while providing inner ring support.

[0078] Please refer to Figure 3 In one embodiment of the present invention, one of the focal points is provided with the solid cylindrical structure and is set as a first solid cylindrical structure 212a, the first pole piece 2111 of the first solid cylindrical structure 212a is connected to the starting end of the first pole piece 2111 in the flat winding body 211, and the second pole piece 2112 of the first solid cylindrical structure 212a is connected to the starting end of the second pole piece 2112 in the flat winding body 211.

[0079] In this example, the solid cylindrical structure arranged at a focal position of the flat winding body 211 is the first solid cylindrical structure 212a, which is wound by a diaphragm, a first pole piece 2111, a diaphragm, a second pole piece 2112, and a diaphragm, that is, the winding stacking sequence of the first solid cylindrical structure 212a is the same as the winding stacking sequence of the flat winding body 211. In this way, the first solid cylindrical structure 212a is connected to the starting end of the first pole piece 2111 and the starting end of the second pole piece 2112 in the flat winding body 211, and the winding tail end of the solid cylindrical structure can be directly not cut off, and the flat winding body 211 can be directly wound. In this example, the first solid cylindrical structure 212a itself can be charged and discharged to improve the energy density. In other examples, the first solid column structure 212a may be wound separately, and the flat winding body 211 may be wound separately by a winding needle, and then the first solid column structure 212a may be placed at the corner of the inner circle of the flat winding body 211 for hot pressing.

[0080] The first solid column structure 212a is directly wound according to the original winding method, and then the flat winding body 211 is wound on the outside, which simplifies the process and improves the processing efficiency on the basis of providing inner circle support. It can also be charged and discharged by itself to improve the energy density.

[0081] Please refer to Figure 4 In one embodiment of the present invention, the solid cylindrical structure is provided at both focal points and is set as a second solid cylindrical structure 212b, wherein a first pole piece 2111 of the second solid cylindrical structure 212b is connected to the starting end of the first pole piece 2111 in the flat winding body 211; The second pole piece 2112 of another second solid cylindrical structure 212 b is connected to the starting end of the second pole piece 2112 in the flat wound body 211 .

[0082] In this embodiment, a second solid cylindrical structure 212b is provided at both focal points, one of which is wound by a diaphragm, a first pole piece 2111, a diaphragm, a second pole piece 2112, and a diaphragm, and the other is wound by a diaphragm, a second pole piece 2112, a diaphragm, a first pole piece 2111, and a diaphragm. One of the second solid cylindrical structures 212b is connected to the starting end of the first pole piece 2111 in the flat winding body 211, which means that the first pole piece 2111 of one of the second solid cylindrical structures 212b is not cut off after winding is completed, and continues to be the starting end of the first pole piece 2111 of the flat winding body 211 for subsequent winding. The other second solid cylindrical structure 212b is connected to the starting end of the second pole piece 2112 in the flat winding body 211, which means that the second pole piece 2112 of the other second solid cylindrical structure 212b is not cut off after winding is completed, and continues to serve as the starting end of the second pole piece 2112 of the flat winding body 211 for subsequent winding.

[0083] In this example, the second solid column structure 212b is set at both focal points to improve the support stability of the inner circle of the flat winding body 211; and it can be charged and discharged by itself to improve energy density. After winding the second solid column structure 212b, the flat winding body 211 can be directly wound, effectively improving processing efficiency.

[0084] In other examples, the second solid cylindrical structure 212b may be wound separately, and the battery cell 21 may be wound separately by a winding needle, and then the second solid cylindrical structure 212b may be placed at the corner of the inner circle of the battery cell for hot pressing to obtain a flat wound body 211.

[0085] Please refer to Figure 5 In one embodiment of the present invention, the solid cylindrical structure is provided at both focal points and is set as a third solid cylindrical structure 212c, wherein one of the third solid cylindrical structures 212c is wound by the first composite pole piece and is connected to the starting end of the first pole piece 2111 in the flat winding body 211; The other third solid column structure 212 c is wound by the second composite pole piece and is connected to the starting end of the second pole piece 2112 in the flat winding body 211 .

[0086] In this embodiment, two third solid cylindrical structures 212c are arranged at two focal positions, wherein one second solid cylindrical structure 212b is wound by a diaphragm, a first pole piece 2111, and a diaphragm, and the other second solid cylindrical structure 212b is wound by a diaphragm, a second pole piece 2112, and a diaphragm, so that the two second solid cylindrical structures 212b can be wound at the same time to improve efficiency. Then, with the two second solid cylindrical structures 212b as axes, the first pole piece 2111 of one second solid cylindrical structure 212b is directly used to wind the first pole piece 2111 of the flat winding body 211, and the second pole piece 2112 of the other second solid cylindrical structure 212b is used to wind the second pole piece 2112 of the flat winding body 211. In other examples, the third solid column structure 212c may be separately wound, and the flat wound body 211 may be separately wound by a winding needle, and then the third solid column structure 212c may be placed at the corner of the inner circle of the flat wound body 211 for hot pressing.

[0087] In this example, the third solid column structure 212c is disposed at both focal points, which not only improves the support stability of the inner circle of the flat winding body 211, but also facilitates the simultaneous molding of two third solid column structures 212c.

[0088] In an embodiment of the present invention, the winding number M of the solid cylindrical structure is greater than or equal to 3 and less than or equal to 10.

[0089] In this example, the number of winding turns of the solid cylindrical structure should not be too many or too few. The number of winding turns M is set to be greater than or equal to 3 and less than or equal to 10, for example, 4, 5, 6, 7, 8, 9, etc., while improving the structural strength and hardness of the solid cylindrical structure, reducing the volume occupied by the flat winding body 211.

[0090] The winding number of the solid column structure within the above range can improve the support stability without affecting the overall volume of the battery cell 20 .

[0091] In one embodiment of the present invention, the ratio of the number of windings M of the solid cylindrical structure to the number of windings N of the flat winding body 211 is greater than or equal to 1 / 10 and less than or equal to 1 / 4.

[0092] In this example, the ratio M / N of the number of windings of the solid cylindrical structure to the number of windings of the flat winding body 211 is greater than or equal to 1 / 10 and less than or equal to 1 / 4, for example, 1 / 9, 1 / 8, 1 / 7, 1 / 6, 1 / 5, etc.

[0093] In this structure, the number of turns of the solid column structure is matched with the number of turns of the flat winding body 211, so that the overall volume can be reduced while satisfying the supporting function.

[0094] In one embodiment of the present invention, a first pole lug is disposed at one end of the solid cylindrical structure, and a second pole lug is disposed at the flat winding body 211 , and the first pole lug is connected to the second pole lug.

[0095] In this example, on the basis of limiting or not limiting the connection between the solid column structure and the flat winding body 211 through the first pole piece 2111 and / or the second pole piece 2112, a first pole ear is provided at one end of the solid column structure in the height direction, and the pole ear can be a positive pole ear or a negative pole ear. Correspondingly, a second pole ear is connected to the same side in the height direction of the flat winding body 211, and the polarity of the second pole ear is opposite to that of the first pole ear. The first pole ear and the second pole ear are connected by welding and fixed to the pole column. Optionally, the solid column structure is located at the corner of the flat winding body 211, so the second pole ear is located at the corner of the flat winding body 211, which is more convenient for connection.

[0096] This structure can further improve the structural stability of the overall wound battery core 21 .

[0097] In one embodiment of the present invention, the outermost pole piece of the flat winding body 211 is the first pole piece 2111 , and the first pole piece 2111 is the anode pole piece.

[0098] It should be noted that the outermost circle refers to the outermost circle of the electrode structure after winding to form the battery core, that is, the electrode part that is not wrapped inside and exposed. In this example, the outermost electrode of the flat winding body 211 is set as the anode electrode, that is, the structure of the anode wrapping the cathode can provide mechanical support, reduce the risk of short circuit, and make the current density uniform.

[0099] The outer ring electrode piece is set as the anode electrode piece to improve the performance of the battery cell 20.

[0100] In one embodiment of the present invention, the tail end of the outermost circle of the first pole piece 2111 is located at a corner of the flat winding body 211 .

[0101] In this example, the tail end of the first pole piece 2111 of the outermost circle, that is, the end of the pole piece after being cut off at the end of winding, corresponds to the corner position of the flat winding body 211, so as to facilitate clamping and fixing.

[0102] The present invention further provides a wound battery cell 21, wherein the wound battery cell 21 comprises a flat wound body 211 formed by sequentially stacking a separator, a first pole piece 2111 and a second pole piece 2112 with opposite polarities, wound along a virtual axis; The starting end of the first pole piece 2111 and / or the starting end of the second pole piece 2112 in the flat winding body 211 is connected with a solid column structure, and the solid column structure is formed by winding the first composite pole piece and / or the second composite pole piece.

[0103] The flat winding body 211 is also known as a racetrack-type battery cell, which has a hollow structure inside. The starting end of the first pole piece 2111 and / or the starting end of the second pole piece 2112 in the flat winding body 211 refers to the end where the winding starts, and a solid column structure is connected here, that is, a solid column structure is provided in the hollow position of the inner circle of the flat winding body 211. The solid structure stability of the solid column structure is used to provide support and buffer for the inner circle of the flat winding body 211, thereby reducing the situation where the inner circle of the wound battery cell 21 breaks or loses powder after hot pressing or expansion. At the same time, the solid column structure is wound by the first composite pole piece, or by the second composite pole piece, or by the first composite pole piece and the second composite pole piece. There is no need to add other additional structures, which saves processes, and can increase energy density and improve the performance of the battery cell 20. Among them, the first composite pole piece and the second composite pole piece refer to the structure discussed above.

[0104] The present invention further provides a battery device 100, which includes any of the above-mentioned battery cells 20. The battery cell 20 of the battery device 100 adopts all the technical solutions of all the above-mentioned embodiments, and thus has at least all the beneficial effects brought by the technical solutions of the above-mentioned embodiments, which will not be described one by one here.

[0105] The battery device 100 may be a battery module or a battery pack.

[0106] The present invention further provides an electric device, comprising any of the above-mentioned battery devices 100. The battery device 100 of the electric device adopts all the technical solutions of all the above-mentioned embodiments, and thus has at least all the beneficial effects brought by the technical solutions of the above-mentioned embodiments, which will not be described one by one here.

[0107] The power-consuming device may be a mobile phone, a laptop computer, a battery car, an electric car, an energy storage station, etc. The present application does not limit the specific type of the power-consuming device. When the power-consuming device includes the battery device 100, the battery device 100 may provide power.

[0108] The above description is only a preferred embodiment of the present invention, and does not limit the patent scope of the present invention. All equivalent structural changes made by using the contents of the present invention specification and drawings under the inventive concept of the present invention, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A battery cell, characterized in that: The battery cell comprises: a housing having a mounting cavity; and A wound battery cell, the wound battery cell is arranged in the installation cavity, and the wound battery cell comprises a flat wound body formed by winding a diaphragm stacked in sequence, a first pole piece and a second pole piece with opposite polarities; The starting end of the first pole piece and / or the starting end of the second pole piece in the flat winding body are connected to a solid cylindrical structure, and the solid cylindrical structure is formed by winding the first composite pole piece and / or the second composite pole piece. The cross-section of the flat winding body has two spaced-apart focal points, and the solid cylindrical structure is located at the position of at least one of the focal points.

2. The battery cell according to claim 1, characterized in that: The cross section of the solid column structure is circular.

3. The battery cell according to claim 2, characterized in that: The outer diameter of the solid cylindrical structure is the same as the inner diameter of the corner of the flat winding body, and the outer side of the solid cylindrical structure is attached to the inner surface of the corner of the flat winding body.

4. The battery cell according to any one of claims 1 to 3, characterized in that: The first composite pole piece includes the first pole piece, and the solid cylindrical structure is formed by winding the first pole piece; Alternatively, the first composite pole piece includes the first pole piece and the diaphragm, and the solid column structure is formed by stacking and winding the diaphragm, the first pole piece and the diaphragm in sequence.

5. The battery cell according to any one of claims 1 to 3, characterized in that: The second composite pole piece includes the second pole piece, and the solid cylindrical structure is formed by winding the second pole piece; Alternatively, the second composite pole piece includes the second pole piece and the diaphragm, and the solid column structure is formed by stacking and winding the diaphragm, the second pole piece and the diaphragm in sequence.

6. The battery cell according to any one of claims 1 to 3, characterized in that: The first composite pole piece includes the first pole piece and the diaphragm, the second composite pole piece includes the second pole piece and the diaphragm, and the solid column structure is formed by winding the diaphragm, the first pole piece, the diaphragm, the second pole piece and the diaphragm in sequence.

7. The battery cell according to claim 6, characterized in that: The solid cylindrical structure is provided at one of the focal points and is set as a first solid cylindrical structure, the first pole piece of the first solid cylindrical structure is connected to the starting end of the first pole piece in the flat winding body, and the second pole piece of the first solid cylindrical structure is connected to the starting end of the second pole piece in the flat winding body.

8. The battery cell according to claim 6, characterized in that: The solid cylindrical structure is provided at both focal points and is set as a second solid cylindrical structure, wherein a first pole piece of the second solid cylindrical structure is connected to a starting end of the first pole piece in the flat winding body; Another second pole piece of the second solid cylindrical structure is connected to the starting end of the second pole piece in the flat winding body.

9. The battery cell according to any one of claims 1 to 3, characterized in that: The solid cylindrical structure is provided at both focal points and is set as a third solid cylindrical structure, wherein one of the third solid cylindrical structures is wound by the first composite pole piece and is connected to the starting end of the first pole piece in the flat winding body; The other third solid cylindrical structure is wound by the second composite pole piece and is connected to the starting end of the second pole piece in the flat winding body.

10. The battery cell according to any one of claims 1 to 3, characterized in that: The winding number M of the solid cylindrical structure is greater than or equal to 3 and less than or equal to 10.

11. The battery cell according to any one of claims 1 to 3, characterized in that: The ratio of the number of winding turns M of the solid cylindrical structure to the number of winding turns N of the flat winding body is greater than or equal to 1 / 10 and less than or equal to 1 / 4.

12. The battery cell according to any one of claims 1 to 3, characterized in that: A first pole lug is disposed at one end of the solid column structure, and a second pole lug is disposed on the flat winding body, and the first pole lug is connected to the second pole lug.

13. The battery cell according to any one of claims 1 to 3, characterized in that: The outermost pole piece of the flat winding body is a first pole piece, and the first pole piece is an anode pole piece.

14. A wound battery cell, characterized in that: The wound battery core comprises a flat wound body formed by winding a diaphragm, a first pole piece and a second pole piece with opposite polarities stacked in sequence; The starting end of the first pole piece and / or the starting end of the second pole piece in the flat winding body are connected with a solid column structure, and the solid column structure is formed by winding the first composite pole piece and / or the second composite pole piece.

15. A battery device, characterized in that: The battery device comprises the battery cell according to any one of claims 1 to 13.

16. An electrical equipment, characterized in that: Comprising the battery device as claimed in claim 15.

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