Battery monomer, battery and electric equipment
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- CONTEMPORARY AMPEREX TECHNOLOGY CO LTD
- Filing Date
- 2024-07-19
- Publication Date
- 2026-05-05
AI Technical Summary
The internal electrode sheets of a battery cell are prone to loosening, which leads to an increase in the distance between the cathode and anode electrodes, resulting in lithium plating.
A buffer is installed in the center hole of the battery cell winding. The buffer is connected to the electrode and provides support to balance the expansion force during charging and discharging and prevent the electrode from loosening.
It effectively improves the problem of loose electrode sheets, reduces the probability of lithium plating, and improves the reliability of battery cells.
Smart Images
Figure CN121986397A_ABST
Abstract
Description
Battery cells, batteries and electrical equipment Technical Field
[0001] This application relates to the field of battery cell technology, and in particular provides a battery cell, a battery, and an electrical device. Background Technology
[0002] Energy conservation and emission reduction are key to the sustainable development of the automotive industry, and electric vehicles, due to their energy-saving and environmentally friendly advantages, have become an important component of this sustainable development. For electric vehicles, battery technology is a crucial factor in their development.
[0003] A battery cell typically consists of a casing, electrode assembly, and electrolyte, with the electrolyte and electrode assembly sealed within the casing. In electrode assembly design, a winding method is commonly used; this involves placing the cathode, anode, and separator at intervals and winding them around a winding needle to form a coil. However, after winding is complete and the core is removed from the coil, the cathode and anode electrodes within the coil become loose due to the lack of internal support. This leads to an increased gap between the cathode and anode electrodes, resulting in lithium plating.
[0004] Application content
[0005] The purpose of this application is to provide a battery cell, a battery, and an electrical device, which aims to solve the problem that the electrode sheets in the winding body are prone to loosening, leading to lithium plating.
[0006] To achieve the above objectives, the technical solution adopted in the embodiments of this application is as follows:
[0007] In a first aspect, embodiments of this application provide a battery cell including an electrode assembly and a buffer. The electrode assembly includes a first electrode, a second electrode, and a separator located between the first electrode and the second electrode. The first electrode, the second electrode, and the separator are wound together along a winding direction to form a wound body, and a central hole is formed at the center of the wound body along the winding axis. The winding direction is perpendicular to the winding axis. The buffer is at least partially disposed in the central hole and is connected to the first electrode and / or the second electrode.
[0008] The beneficial effects of the embodiments of this application are as follows: The battery cell provided in the embodiments of this application provides at least a partial buffer in the central hole of the winding body and connects the buffer to the first electrode and / or the second electrode. Thus, the buffer can support the first electrode and the second electrode in the central hole of the winding body to balance the expansion force generated by the expansion during the charging and discharging of the battery cell. This can effectively improve the problem of the first electrode and the second electrode becoming loose at the central hole of the winding body and reduce the probability of lithium plating.
[0009] In some embodiments, the first electrode sheet has a blank foil region and a coating region sequentially formed along the winding direction, the coating region being used to coat an active material layer; in the direction opposite to the winding direction, at least a portion of the blank foil region extends beyond the second electrode sheet, and a buffer is connected to the blank foil region.
[0010] By adopting the above technical solution, the empty foil area and the coating area are sequentially formed on the first electrode sheet along the winding direction, and at least a portion of the empty foil area extends beyond the second electrode sheet in the direction opposite to the winding direction. Thus, after connecting the buffer member on the empty foil area, when the first electrode sheet, the second electrode sheet, and the separator are wound along the winding direction to form a wound body, at least a portion of the empty foil area can be located in the central hole, and at least a portion of the buffer member will also be located in the central hole. In this way, the buffer member can achieve the supporting function for the coating area of the first electrode sheet and the second electrode sheet.
[0011] In some embodiments, the empty foil area is wound along the winding direction to form at least one empty foil bend; a buffer is connected to the empty foil bend.
[0012] By adopting the above technical solution, the buffer can support the coating area of the first electrode and the second electrode at the bent part of the empty foil, thereby increasing the corner gap between the coating area of the first electrode and the second electrode at the bend, thereby reducing the probability of brittle fracture of the coating area of the first electrode and the second electrode.
[0013] In some embodiments, the empty foil area is wound along the winding direction and alternately forms at least one straight empty foil portion and at least one bent empty foil portion; a buffer is connected to the straight empty foil portion and the bent empty foil portion.
[0014] By adopting the above technical solution, the buffer can be connected to both the straight part and the bent part of the empty foil at the same time. With the buffer supporting the coating area of the first electrode and the second electrode, the connection stability of the buffer is better.
[0015] In some embodiments, at least one flat portion of the empty foil is formed along the winding direction in the empty foil area; a buffer is connected to the flat portion of the empty foil.
[0016] By adopting the above technical solution, the buffer can support the coating area of the first electrode and the second electrode on the surface of the flat part of the empty foil to balance the effect of the expansion force.
[0017] In some embodiments, the buffer includes a first buffer portion disposed inside the empty foil area.
[0018] By adopting the above technical solution, the first buffer section is located inside the empty foil area, so that the first buffer section can support the first electrode and the second electrode on the innermost side of the winding body.
[0019] In some embodiments, the buffer includes a second buffer portion disposed outside the empty foil area.
[0020] By adopting the above technical solution, the second buffer section can be set outside the empty foil area, thereby improving the support effect on the first and second electrodes.
[0021] In some embodiments, the first buffer section and the second buffer section are disposed opposite to each other.
[0022] By adopting the above technical solution, the first buffer part and the second buffer part are located on the inner and outer sides of the empty foil area and are arranged opposite to each other. Therefore, the first buffer part and the second buffer part work together to support the first electrode and the second electrode.
[0023] In some embodiments, in the winding direction, the length o of the buffer is less than or equal to the length p of the empty foil area.
[0024] By adopting the above technical solution, the length o of the buffer is set to be less than or equal to the length p of the empty foil area, so as to reduce the impact of the buffer being too long and extending into the coating area and affecting the coated active material layer, thereby reducing the impact on the energy density of the battery cell.
[0025] In some embodiments, in the winding direction, the end of the buffer forms a gap with the beginning of the coating area.
[0026] By adopting the above technical solution, a gap is formed between the end of the buffer and the beginning of the coating area, meaning that the buffer will not extend onto the coating area, thereby reducing the impact of the buffer on the active material layer and thus reducing the impact on the energy density of the battery cell.
[0027] In some embodiments, the first electrode is a cathode electrode and the second electrode is an anode electrode.
[0028] By adopting the above technical solution, the buffer pad can be connected to the cathode electrode and / or anode electrode to achieve the effect of support.
[0029] In some embodiments, the first electrode is an anode electrode and the second electrode is a cathode electrode.
[0030] By adopting the above technical solution, the buffer pad can be connected to the cathode electrode and / or anode electrode to achieve the effect of support.
[0031] In some embodiments, the first electrode includes a single-sided coating area and a double-sided coating area arranged sequentially along the winding direction, and a buffer is disposed inside the single-sided coating area; in a direction opposite to the winding direction, at least a portion of the single-sided coating area extends beyond the second electrode.
[0032] By adopting the above technical solution, the inner side of the single-sided coating area is used to connect the buffer to achieve the support effect, while the outer side of the single-sided coating area can be coated with an active material layer. Thus, the active material layer on the single-sided coating area can be fully utilized to improve the energy density of the battery cell.
[0033] In some embodiments, in the winding axial direction, the width of the buffer is less than or equal to the width of the winding body, and the buffer does not extend beyond the central hole.
[0034] By adopting the above technical solution, the buffer is configured not to extend beyond the center hole in the winding axial direction, which can effectively reduce the impact of the buffer on the winding operation.
[0035] In some embodiments, the wound body has a width a in the winding axial direction, and the buffer has a width b, wherein 0 ≤ a - b ≤ 2 mm.
[0036] By adopting the above technical solution, in the direction perpendicular to the winding direction, the width of the buffer can be set to be the same as the width of the winding body to within the range of 2 mm narrower than the width of the winding body; if the width of the buffer is too wide, it may affect the winding process, and if the width of the buffer is too narrow, it may cause stress marks to form on the first electrode and the second electrode.
[0037] In some embodiments, 0 ≤ a - b ≤ 1 mm.
[0038] By adopting the above technical solution, and further limiting the difference in width between the winding body and the buffer to greater than or equal to zero and less than or equal to 1 mm, the probability of stress streaks forming on the first and second electrodes can be further reduced.
[0039] In some embodiments, the buffer has a compression ratio c, where 30% ≤ c ≤ 90%.
[0040] By adopting the above technical solution, the compression rate of the buffer is limited to greater than or equal to 30% and less than or equal to 90%. Within this range, the buffer has a better support effect while having a lower impact on space occupation.
[0041] In some embodiments, 50% ≤ c ≤ 70%.
[0042] By adopting the above technical solution, the compression rate of the buffer is further limited to greater than or equal to 50% and less than or equal to 70%, thereby further improving the support effect of the buffer within this range and further reducing the impact of the buffer on space occupation.
[0043] In some embodiments, the buffer has a thickness d, where 0.5 mm ≤ d ≤ 4 mm.
[0044] By adopting the above technical solution, the thickness d of the buffer is limited to greater than or equal to 0.5 mm and less than or equal to 4 mm, so that the buffer has sufficient thickness to achieve the supporting function. At the same time, the buffer has a low impact on the space occupied by the winding body.
[0045] In some embodiments, 0.5mm ≤ d ≤ 2mm.
[0046] By adopting the above technical solution, the thickness d of the buffer is further limited to greater than or equal to 0.5 mm and less than or equal to 2 mm, so as to further reduce the impact of the buffer on the space occupied by the winding body.
[0047] In some embodiments, at least one end of the buffer has a chamfered structure in the winding direction.
[0048] By adopting the above technical solution and setting a chamfer structure on the buffer, the probability of the buffer end being squeezed and indented by the first and second pole pieces during the cold pressing and shaping process of the winding body can be effectively reduced.
[0049] In some embodiments, the cushioning element includes any one of polypropylene cushioning element, polyethylene cushioning element, plexiglass cushioning element, polyester cushioning element, and polycarbonate cushioning element.
[0050] By adopting the above technical solution, any one of polypropylene buffer, polyethylene buffer, plexiglass buffer, polyester buffer, and polycarbonate buffer can be used as a buffer to support the first and second electrodes.
[0051] In some embodiments, the buffer is connected to the isolator.
[0052] By adopting the above technical solution, the buffer is connected to the first pole piece and / or the second pole piece, and the buffer is set to be connected to the isolation piece, thereby effectively improving the stability of the buffer and reducing the probability of the buffer being misaligned during the winding process.
[0053] Secondly, embodiments of this application also provide a battery, including a housing and a battery cell as described above, wherein the battery cell is housed within the housing.
[0054] The beneficial effects of the embodiments of this application are as follows: The battery provided in the embodiments of this application includes the above-mentioned battery cells. Based on the better reliability of the above-mentioned battery cells, the battery also has better reliability.
[0055] Thirdly, embodiments of this application also provide an electrical device, including a battery as described above, the battery being used to provide electrical energy.
[0056] The beneficial effects of the embodiments of this application are as follows: The electrical equipment provided in the embodiments of this application includes the battery described above. Based on the better reliability of the battery, the electrical equipment also has better reliability. Attached Figure Description
[0057] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or related technologies will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0058] Figure 1 is a structural schematic diagram of the vehicle provided in an embodiment of this application;
[0059] Figure 2 is an exploded view of the battery provided in an embodiment of this application;
[0060] Figure 3 is an exploded structural diagram of a battery cell provided in an embodiment of this application;
[0061] Figure 4 is a schematic diagram of the structure of the first type of wound body provided in the embodiment of this application;
[0062] Figure 5 is a magnified view of part A in Figure 4;
[0063] Figure 6 is a structural schematic diagram of the first pole sheet of the first type of wound body provided in the embodiment of this application in the unfolded state;
[0064] Figure 7 is a schematic diagram of a connection structure between the first pole piece and the buffer member of the first type of wound body provided in the embodiment of this application;
[0065] Figure 8 is a schematic diagram of another connection structure between the first pole piece and the buffer member of the first type of winding body provided in the embodiments of this application;
[0066] Figure 9 is a schematic diagram of the structure of the second type of wound body provided in the embodiment of this application;
[0067] Figure 10 is a magnified view of part B in Figure 9;
[0068] Figure 11 is a structural schematic diagram of the third type of wound body provided in the embodiment of this application;
[0069] Figure 12 is a magnified view of part C in Figure 11;
[0070] Figure 13 is a magnified view of part D in Figure 11;
[0071] Figure 14 is a schematic diagram of the connection structure between the first pole piece and the buffer member of the third type of wound body provided in the embodiment of this application;
[0072] Figure 15 is a schematic diagram of the winding operation of the third type of winding body provided in the embodiments of this application.
[0073] The reference numerals in the figures are as follows: 1000, vehicle; 100, battery; 200, controller; 300, motor; 10, housing; 11, first part; 12, second part; 20, battery cell; 21, end cap; 21a, electrode terminal; 22, housing; 23, electrode assembly; 23a, tab; 23b, winding body; 23b1, center hole; 231, first electrode; 231a, empty foil area; 231a1, straight portion of empty foil; 231a2, bent portion of empty foil; 231b, coating area; 231c, active material layer; 231d, single-sided coating area; 231f, double-sided coating area; 232, second electrode; 233, separator; 24, buffer; 241, chamfered structure; 24a, first buffer part; 24b, second buffer part; 30, core; X, winding direction; Y, winding axis. Detailed Implementation
[0074] The embodiments of this application are described in detail below. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application.
[0075] In the description of this application, it should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.
[0076] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.
[0077] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.
[0078] Currently, judging from market trends, the application of power batteries is becoming increasingly widespread. Power batteries are not only used in energy storage systems such as hydropower, thermal power, wind power, and solar power plants, but also extensively used in electric vehicles such as electric bicycles, electric motorcycles, and electric cars, as well as in military equipment and aerospace. With the continuous expansion of power battery applications, market demand is also constantly increasing.
[0079] A battery cell typically consists of a casing, electrode assembly, and electrolyte, with the electrolyte and electrode assembly sealed within the casing. In electrode assembly design, a winding method is commonly used; this involves placing cathode, anode, and separator electrodes spaced apart and winding them around a winding needle to form a coil. However, after winding is complete and the winding needle is removed, the cathode and anode electrodes within the coil become loose due to the lack of internal support. This leads to an increased gap between the cathode and anode electrodes, resulting in lithium plating.
[0080] Based on the above considerations, in order to solve the problem of lithium plating caused by the loosening of the electrodes in the winding body, a battery cell is designed. The winding body is formed by winding a first electrode, a second electrode, and a separator along the winding direction, and a central hole is formed in the center of the winding body along the winding axis. At least part of the buffer is placed in the central hole and connected to the first electrode and / or the second electrode. Thus, the buffer can support the first electrode and the second electrode in the central hole of the winding body, which can effectively improve the problem of the first electrode and the second electrode becoming loose. At the same time, it can also balance the expansion force generated by the expansion during the charging and discharging of the battery cell, so as to effectively reduce the probability of lithium plating.
[0081] The battery cells disclosed in this application can be used in electrical devices that use batteries as a power source or in various energy storage systems that use batteries as energy storage elements. Electrical devices can be, but are not limited to, mobile phones, tablets, laptops, electric toys, power tools, electric vehicles, electric cars, ships, spacecraft, etc. Electric toys can include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc. Spacecraft can include airplanes, rockets, space shuttles, and spacecraft, etc.
[0082] For ease of explanation, the following embodiments will be described using a vehicle 1000 as an example of an electrical device according to an embodiment of this application.
[0083] Please refer to Figure 1, which is a structural schematic diagram of a vehicle 1000 provided in some embodiments of this application. The vehicle 1000 can be a gasoline-powered vehicle, a natural gas-powered vehicle, or a new energy vehicle. New energy vehicles can be pure electric vehicles, hybrid electric vehicles, or range-extended electric vehicles, etc. A battery 100 is disposed inside the vehicle 1000, and the battery 100 can be located at the bottom, front, or rear of the vehicle 1000. The battery 100 can be used to power the vehicle 1000; for example, the battery 100 can serve as the operating power source for the vehicle 1000. The vehicle 1000 may also include a controller 200 and a motor 300. The controller 200 is used to control the battery 100 to supply power to the motor 300, for example, to meet the power needs of the vehicle 1000 during startup, navigation, and driving.
[0084] In some embodiments of this application, the battery 100 can not only serve as the operating power source for the vehicle 1000, but also as the driving power source for the vehicle 1000, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000.
[0085] Please refer to Figure 2, which is an exploded view of a battery 100 provided in some embodiments of this application. The battery 100 includes a housing 10 and a battery cell 20, with the battery cell 20 housed within the housing 10. The housing 10 provides a space for the battery cell 20 and can have various structures. In some embodiments, the housing 10 may include a first portion 11 and a second portion 12, which overlap each other, jointly defining a space for accommodating the battery cell 20. The second portion 12 may be a hollow structure with one open end, and the first portion 11 may be a plate-like structure, covering the open side of the second portion 12 so that the first portion 11 and the second portion 12 jointly define the space. Alternatively, the first portion 11 and the second portion 12 may both be hollow structures with one open side, with the open side of the first portion 11 covering the open side of the second portion 12. Of course, the housing 10 formed by the first portion 11 and the second portion 12 can have various shapes, such as a cylinder, a cuboid, etc.
[0086] In battery 100, there can be multiple battery cells 20, which can be connected in series, parallel, or in a mixed manner. A mixed connection means that multiple battery cells 20 are connected in both series and parallel configurations. Multiple battery cells 20 can be directly connected in series, parallel, or in a mixed manner, and then the entire assembly of the multiple battery cells 20 is housed within the housing 10. Alternatively, battery 100 can also be composed of multiple battery cells 20 first connected in series, parallel, or in a mixed manner to form a battery module, and then multiple battery modules are connected in series, parallel, or in a mixed manner to form a whole, which is also housed within the housing 10. Battery 100 may also include other structures; for example, it may include a busbar component for electrical connection between the multiple battery cells 20.
[0087] Each battery cell 20 can be a secondary battery or a primary battery; it can also be a lithium-sulfur battery, a sodium-ion battery, or a magnesium-ion battery, but is not limited to these. The battery cell 20 can be cylindrical, flat, cuboid, or other shapes.
[0088] Please refer to Figure 3, which is an exploded structural diagram of a battery cell 20 provided in some embodiments of this application. A battery cell 20 refers to the smallest unit that makes up the battery 100. As shown in Figure 3, the battery cell 20 includes a casing (including end caps 21 and housing 22), electrode assemblies 23, and other functional components.
[0089] End cap 21 refers to a component that covers the opening of housing 22 to isolate the internal environment of battery cell 20 from the external environment. The shape of end cap 21 can be adapted to the shape of housing 22 to fit it. Optionally, end cap 21 can be made of a material with certain hardness and strength (such as aluminum alloy), so that end cap 21 is not easily deformed under pressure and impact, allowing battery cell 20 to have higher structural strength and improved reliability. Functional components such as electrode terminals 21a can be provided on end cap 21. Electrode terminals 21a can be used for electrical connection with electrode assembly 23 to output or input electrical energy to battery cell 20. In some embodiments, end cap 21 can also be provided with a pressure relief mechanism for releasing internal pressure when the internal pressure or temperature of battery cell 20 reaches a threshold. The material of end cap 21 can also be various, such as, but not limited to, copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc. In some embodiments, an insulating element may be provided on the inner side of the end cap 21. The insulating element can be used to isolate the electrical connection components within the housing 22 from the end cap 21 to reduce the risk of short circuits. For example, the insulating element may be made of plastic, rubber, etc.
[0090] The housing 22 is a component used to cooperate with the end cap 21 to form the internal environment of the battery cell 20. This internal environment can accommodate the electrode assembly 23, electrolyte, and other components. The housing 22 and the end cap 21 can be independent components. An opening can be provided on the housing 22, and the end cap 21 closes the opening to form the internal environment of the battery cell 20. Alternatively, the end cap 21 and the housing 22 can be integrated. Specifically, the end cap 21 and the housing 22 can form a common connecting surface before other components are inserted into the housing. When it is necessary to encapsulate the interior of the housing 22, the end cap 21 closes the housing 22. The housing 22 can be of various shapes and sizes, such as cuboid, cylindrical, hexagonal prism, etc. Specifically, the shape of the housing 22 can be determined according to the specific shape and size of the electrode assembly 23. The housing 22 can be made of various materials, such as, but not limited to, copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc.
[0091] Electrode assembly 23 is the component in the battery cell 20 where electrochemical reactions occur. The casing 22 may contain one or more electrode assemblies 23. The electrode assembly 23 is mainly formed by winding or stacking anode and cathode electrodes, and typically a separator, such as a separator membrane, is provided between the anode and cathode electrodes. The portions of the anode and cathode electrodes containing active material constitute the main body of the electrode assembly 23, while the portions of the anode and cathode electrodes without active material each constitute a tab 23a. The anode and cathode tabs may be located together at one end of the main body or separately at both ends of the main body. During the charging and discharging process of the battery, the anode and cathode active materials react with the electrolyte, and the tabs 23a connect to the electrode terminals 21a to form a current loop.
[0092] According to some embodiments of this application, referring to Figures 3 and 4 or Figures 9 or 11, this application provides a battery cell 20, including an electrode assembly 23 and a buffer 24. The electrode assembly 23 includes a first electrode 231, a second electrode 232, and a separator 233 located between the first electrode 231 and the second electrode 232. The first electrode 231, the second electrode 232, and the separator 233 are wound along the winding direction X to form a wound body 23b. The center of the wound body 23b forms a central hole 23b1 along the winding axis Y. The winding direction X is perpendicular to the winding axis Y. The buffer 24 is at least partially disposed in the central hole 23b1 and is connected to the first electrode 231 and / or the second electrode 232.
[0093] The first electrode 231 and the second electrode 232 are capable of reacting in the electrolyte to generate an electric current. It should be understood that one of the first electrode 231 and the second electrode 232 has a cathode active material (e.g., anions), and the other has an anode active material (e.g., cations). Thus, the cathode active material and the anode active material react in the electrolyte to generate an electric current.
[0094] The winding direction X refers to the direction in which the first electrode 231, the spacer 233, and the second electrode 232 are stacked and wound in sequence. In some embodiments, the first electrode 231 and the second electrode 232 can be aligned at their starting ends in the winding direction X to form a winding, and the center hole 23b1 is formed by the electrode wound into the innermost circle. Alternatively, in other embodiments, in a direction opposite to the winding direction X, the first electrode 231 can be wound beyond the second electrode 232, or the second electrode 232 can be wound beyond the first electrode 231, with the portion of the first electrode 231 that extends beyond being wound into the innermost circle of the winding body 23b.
[0095] The winding axis Y refers to the direction perpendicular to the winding direction X. The first electrode 231, the spacer 233, and the second electrode 232 are stacked sequentially and wound along the winding direction X and around the winding axis Y to form a wound body 23b. Understandably, the first electrode 231, the spacer 233, and the second electrode 232 are stacked sequentially and wound around the core 30 to form the wound body 23b. After the winding operation is completed, the core 30 is removed, thus forming a hollow central hole 23b1 in the middle region of the wound body 23b, as shown in Figure 15.
[0096] The buffer element 24 is disposed within the central hole 23b1 and supports the first electrode 231 and the second electrode 232 to reduce the probability of the first electrode 231 and the second electrode 232 becoming loose within the central hole 23b1. Optionally, the buffer element 24 includes, but is not limited to, buffer pads, buffer layers, buffer sheets, and other buffer support structures. The buffer element 24 can be connected to and fixed to the first electrode 231 and / or the second electrode 232 by means of thermal bonding, adhesive bonding, etc.
[0097] The buffer element 24 is at least partially disposed within the central hole 23b1; optionally, the buffer element 24 may be completely housed within the central hole 23b1; or, the buffer element 24 may be partially housed within the central hole 23b1, with another portion of the buffer element 24 connected between the second pole piece 232 and the first pole piece 231 and wound into the interior of the winding body 23b. The number of buffer elements 24 may be one, or the number of buffer elements 24 may be multiple, and the multiple buffer elements 24 may be connected continuously or intermittently on the first pole piece 231 and / or the second pole piece 232.
[0098] For example, in some embodiments, the buffer 24 may be connected to the first electrode 231, and at least a portion of the buffer 24 may be accommodated within the central hole 23b1; or, in other embodiments, the buffer 24 may be connected to the second electrode 232, and at least a portion of the buffer 24 may be accommodated within the central hole 23b1; or, in other embodiments, the buffer 24 may be connected to both the first electrode 231 and the second electrode 232 simultaneously (for example, by folding the buffer 24 so that the buffer 24 bypasses the separator 233 and is simultaneously connected to the first electrode 231 and the second electrode 232), and at least a portion of the buffer 24 may be accommodated within the central hole 23b1.
[0099] The battery cell 20 provided in this application embodiment has at least a partial buffer 24 provided in the central hole 23b1 of the winding body 23b, and the buffer 24 is connected to the first electrode 231 and / or the second electrode 232. Thus, the buffer 24 can support the first electrode 231 and the second electrode 232 in the central hole 23b1 of the winding body 23b, so as to balance the expansion force generated by the expansion during the charging and discharging process of the battery cell 20. This can effectively improve the problem of the first electrode 231 and the second electrode 232 becoming loose at the central hole 23b1 of the winding body 23b, and reduce the probability of lithium plating.
[0100] Referring to Figures 4 to 6, as well as Figures 9 and 10, in some embodiments, the first electrode 231 is sequentially formed with an empty foil region 231a and a coating region 231b along the winding direction X. The coating region 231b is used to coat the active material layer 231c. In the direction opposite to the winding direction X, at least a portion of the empty foil region 231a extends beyond the second electrode 232, and the buffer member 24 is connected to the empty foil region 231a.
[0101] The first electrode 231 includes an empty foil region 231a and a coating region 231b; wherein, the coating region 231b is used to coat an active material layer 231c, and the active material layer 231c reacts with the second electrode 232 in the electrolyte to form an electric current.
[0102] For example, when the first electrode 231 is a cathode electrode, an empty foil area 231a and a coating area 231b can be provided on the cathode electrode, and the active material layer 231c coated on the coating area 231b is the cathode active material layer, as shown in Figures 4 and 5. Alternatively, when the first electrode 231 is an anode electrode, an empty foil area 231a and a coating area 231b can be provided on the anode electrode, and the active material layer 231c coated on the coating area 231b is the anode active material layer, as shown in Figures 9 and 10.
[0103] The empty foil area 231a refers to the portion of the first electrode 231 that is not coated with the active material layer 231c; the empty foil area 231a is used to connect the buffer 24. Optionally, the buffer 24 can be connected to the empty foil area 231a by means of thermal bonding, adhesive bonding or other methods to achieve fixation.
[0104] The empty foil region 231a and the coating region 231b are formed sequentially along the winding direction X, with the empty foil region 231a formed upstream of the coating region 231b in the winding direction X. Therefore, during the winding operation, the empty foil region 231a can be wound into the innermost part of the wound body 23b, so that at least a portion of the empty foil region 231a will be within the central hole 23b1. Optionally, depending on the different lengths of the empty foil region 231a in the winding direction X, the empty foil region 231a can form a winding structure with multiple turns, such as half a turn, one turn, or one and a half turns, within the central hole 23b1 of the wound body 23b. For example, in some specific embodiments, the first electrode 231, the spacer 233 and the second electrode 232 are stacked in sequence, and in the winding direction X, the starting end of the second electrode 232 is aligned with the starting end of the coating area 231b of the first electrode 231, or the starting end of the second electrode 232 is aligned with the middle region of the empty foil area 231a of the first electrode 231; thereby, at least a portion of the empty foil area 231a can extend into the central hole 23b1.
[0105] For example, when the first electrode 231 surrounds and forms the central hole 23b1 (for example, the coating area 231b of the first electrode 231 surrounds and forms the central hole 23b1), the empty foil area 231a can extend into the central hole 23b1, as shown in FIG9; when the second electrode 232 surrounds and forms the central hole 23b1, the empty foil area 231a of the first electrode 231 can extend into the central hole 23b1, as shown in FIG4.
[0106] The buffer 24 is connected to the empty foil area 231a and is wound into the winding body 23b simultaneously with the empty foil area 231a. Thus, at least a portion of the buffer 24 can also be wound into the central hole 23b1 and support the first electrode 231 and the second electrode 232 within the central hole 23b1.
[0107] With this configuration, the empty foil area 231a and the coating area 231b are sequentially formed on the first electrode 231 along the winding direction X, and at least a portion of the empty foil area 231a extends beyond the second electrode 232 in a direction opposite to the winding direction X. Thus, after the buffer member 24 is connected to the empty foil area 231a, when the first electrode 231, the second electrode 232, and the separator 233 are wound along the winding direction X to form a wound body 23b, at least a portion of the empty foil area 231a can be located within the central hole 23b1, and thus at least a portion of the buffer member 24 will also be located within the central hole 23b1, thereby enabling the buffer member 24 to provide support for the first electrode 231 and the second electrode 232.
[0108] Referring to Figures 4 to 8, in some embodiments, the empty foil area 231a forms at least one empty foil bend 231a2 along the winding direction X; the buffer 24 is connected to the empty foil bend 231a2.
[0109] Understandably, during the winding process along the X direction, the empty foil region 231a will form one or more bent empty foil portions 231a2 with a bent surface. Optionally, during the winding process along the X direction, the empty foil region 231a may also form a flat structure with a planar surface.
[0110] Optionally, the buffer 24 can be connected to either side of the empty foil bending portion 231a2, as shown in FIG8; or, the buffer 24 can be connected to both opposite sides of the empty foil bending portion 231a2, as shown in FIG7.
[0111] It should be understood that at the point where the empty foil area 231a is wound along the winding direction X to form the empty foil bend 231a2, the coating area 231b of the first electrode 231 and the second electrode 232 will also be wound and correspondingly form a bend or even a folded structure; the coating area 231b of the first electrode 231 and the second electrode 232 are prone to brittle fracture at this point.
[0112] With this configuration, the buffer 24 is connected to the bent portion 231a2 of the empty foil, so that the buffer 24 can provide support for the coating area 231b of the first electrode 231 and the bent structure of the second electrode 232, thereby increasing the corner gap between the coating area 231b of the first electrode 231 and the second electrode 232 at this point, and thus effectively reducing the probability of brittle fracture of the coating area 231b of the first electrode 231 and the second electrode 232 at this point.
[0113] Referring to Figures 4 to 8, in some embodiments, the empty foil area 231a is wound along the winding direction X and alternately forms at least one empty foil straight portion 231a1 and at least one empty foil bent portion 231a2; the buffer member 24 is connected to the empty foil straight portion 231a1 and the empty foil bent portion 231a2.
[0114] Optionally, the buffer 24 can be connected to either side of the flat portion 231a1 and the bent portion 231a2 of the empty foil; or, the buffer 24 can be connected to both sides of the opposite sides of the flat portion 231a1 and the bent portion 231a2 of the empty foil.
[0115] For example, in the first type of embodiment, the empty foil area 231a is wound along the winding direction X and can form an empty foil straight portion 231a1 and an empty foil bent portion 231a2. The opposite ends of the empty foil bent portion 231a2 are respectively connected to the empty foil straight portion 231a1 and the coating area 231b, as shown in FIG7. The buffer member 24 is connected to at least one side surface of the empty foil straight portion 231a1 and the empty foil bent portion 231a2.
[0116] Alternatively, in the second embodiment, the empty foil area 231a is wound along the winding direction X and can form two empty foil straight portions 231a1 and two empty foil bent portions 231a2. The two opposite ends of one empty foil bent portion 231a2 are respectively connected to the two empty foil straight portions 231a1, and the other empty foil bent portion 231a2 is connected to the coating area 231b. Specifically, as shown in FIG8, the buffer member 24 is connected to the inner surface of the empty foil straight portion 231a1 and the empty foil bent portion 231a2, that is, the side surface of the empty foil straight portion 231a1 and the empty foil bent portion 231a2 facing the center of the central hole 23b1.
[0117] Alternatively, in the third embodiment, the empty foil area 231a is wound along the winding direction X and can form two empty foil straight portions 231a1 and two empty foil bent portions 231a2. The empty foil straight portions 231a1 and empty foil bent portions 231a2 are connected alternately in sequence. The last empty foil bent portion 231a2 is connected to the coating area 231b. The buffer member 24 can be connected to at least one side surface of the empty foil straight portion 231a1 and the empty foil bent portion 231a2.
[0118] Alternatively, in the fourth embodiment, the empty foil area 231a is wound along the winding direction X and can form two or more empty foil straight portions 231a1 and two or more empty foil bent portions 231a2, and the buffer member 24 can be connected to at least one side surface of the empty foil straight portion 231a1 and the empty foil bent portion 231a2.
[0119] With this configuration, the buffer 24 can be connected to both the straight portion 231a1 and the bent portion 231a2 of the empty foil. As the buffer 24 supports the coating area 231b of the first electrode 231 and the second electrode 232, the connection stability of the buffer 24 is better.
[0120] Please refer to Figures 4 to 8. In some embodiments, at least one empty foil flat portion 231a1 is formed in the empty foil area 231a along the winding direction X; the buffer 24 is connected to the empty foil flat portion 231a1.
[0121] Optionally, the buffer 24 can be connected to either side of the flat portion 231a1 of the empty foil; or, the buffer 24 can be connected to both opposite sides of the flat portion 231a1 of the empty foil.
[0122] With this configuration, the buffer 24 can support the coating area 231b of the first electrode 231 and the second electrode 232 on the surface of the flat portion 231a1 of the empty foil to balance the effect of the expansion force.
[0123] Please refer to Figures 5 and 8. In some embodiments, the buffer 24 includes a first buffer portion 24a, which is disposed inside the empty foil area 231a.
[0124] The inner side of the empty foil area 231a refers to the side surface of the empty foil area 231a facing the center hole 23b1 of the winding body 23b.
[0125] The first buffer section 24a is a part that has both buffering and supporting capabilities. The first buffer section 24a may be, but is not limited to, a buffer pad structure, a buffer layer structure, a buffer sheet structure, etc.
[0126] With this configuration, the first buffer section 24a is located inside the empty foil area 231a, so that the first buffer section 24a can support the first electrode 231 and the second electrode 232 on the innermost side of the winding body 23b, thereby effectively supporting the first electrode 231 and the second electrode 232, effectively balancing the expansion force generated by the first electrode 231 and the second electrode 232, and supporting the bending points of the first electrode 231 and the second electrode 232, so as to reduce the probability of the first electrode 231 and the second electrode 232 breaking brittlely.
[0127] Please refer to Figures 5 and 7. In some embodiments, the buffer 24 includes a second buffer portion 24b, which is disposed outside the empty foil area 231a.
[0128] The outer side of the empty foil area 231a refers to the side of the empty foil area 231a facing outward from the winding body 23b.
[0129] The second buffer section 24b is a part that has both buffering and support capabilities. The second buffer section 24b may be, but is not limited to, a buffer pad structure, a buffer layer structure, a buffer sheet structure, etc.
[0130] With this configuration, when the first buffer portion 24a is placed inside the empty foil area 231a and forms a support, the second buffer portion 24b can be placed outside the empty foil area 231a. Thus, the second buffer portion 24b can work with the first buffer portion 24a to simultaneously support the coating area 231b of the first electrode 231 and the second electrode 232, thereby further improving the support effect on the coating area 231b of the first electrode 231 and the second electrode 232.
[0131] Please refer to Figures 5 and 7. The first buffer section 24a and the second buffer section 24b are arranged opposite to each other.
[0132] Understandably, the fact that the first buffer portion 24a and the second buffer portion 24b are arranged opposite each other means that, in the thickness direction of the empty foil area 231a, the first buffer portion 24a and the second buffer portion 24b are opposite each other, that is, the first buffer portion 24a and the second buffer portion 24b are distributed in roughly the same position in the thickness direction of the empty foil area 231a.
[0133] With this configuration, the first buffer section 24a and the second buffer section 24b are located on the inner and outer sides of the empty foil area 231a respectively and are arranged opposite to each other. As a result, the first buffer section 24a and the second buffer section 24b work together to support the first electrode 231 and the second electrode 232 more effectively.
[0134] Referring to Figures 5 and 6, in some embodiments, the length o of the buffer 24 in the winding direction X is less than or equal to the length p of the empty foil area 231a.
[0135] The length o of the buffer member 24 is less than the length p of the empty foil area 231a. The buffer member 24 can be connected to the starting end of the empty foil area 231a in the winding direction X; or, the buffer member 24 can be connected to the ending end of the empty foil area 231a in the winding direction X; or, the buffer member 24 can be connected between the starting end and the ending end of the empty foil area 231a in the winding direction X.
[0136] Wherein, the starting end of the buffer member 24 in the winding direction X refers to the end side of the buffer member 24 facing away from the winding direction X; the ending end of the buffer member 24 in the winding direction X refers to the end side of the buffer member 24 facing the winding direction X.
[0137] Similarly, the starting end of the empty foil region 231a in the winding direction X refers to the end side of the empty foil region 231a facing away from the winding direction X; the ending end of the empty foil region 231a in the winding direction X refers to the end side of the empty foil region 231a facing the winding direction X.
[0138] With this configuration, the length o of the buffer 24 is set to be less than the length p of the empty foil area 231a, so as to reduce the impact of the buffer 24 being too long and extending into the coating area 231b and affecting the active material layer 231c coated in the coating area 231b, thereby reducing the impact on the energy density of the battery cell 20.
[0139] Referring to Figures 4 to 6, in some embodiments, in the winding direction X, the end of the buffer 24 forms a gap with the beginning of the coating area 231b.
[0140] With this configuration, the end of the buffer 24 forms a gap with the beginning of the coating area 231b, meaning that the buffer 24 will not extend onto the coating area 231b. This reduces the impact of the buffer 24 on the active material layer 231c, thereby reducing the impact on the energy density of the battery cell 20.
[0141] Referring to Figure 4, in some embodiments, the first electrode 231 is the cathode electrode and the second electrode 232 is the anode electrode.
[0142] In this embodiment, the first electrode 231 can be a cathode electrode, that is, the first electrode 231 has a cathode active material, and the second electrode 232 has an anode active material, and the second electrode 232 is an anode electrode.
[0143] Thus, the buffer 24 can be connected to the cathode electrode and / or the anode electrode within the central hole 23b1 and provide support for the cathode electrode and the anode electrode.
[0144] Referring to Figure 9 or Figure 11, in some embodiments, the first electrode 231 is the anode electrode and the second electrode 232 is the cathode electrode.
[0145] In this embodiment, the first electrode 231 can be an anode electrode, that is, the first electrode 231 has an anode active material, and the second electrode 232 has a cathode active material, and the second electrode 232 is a cathode electrode.
[0146] Thus, the buffer 24 can be connected to the cathode electrode and / or the anode electrode within the central hole 23b1 and provide support for the cathode electrode and the anode electrode.
[0147] Referring to Figures 11 to 14, in some embodiments, the first electrode 231 includes a single-sided coating area 231d and a double-sided coating area 231f arranged sequentially along the winding direction X, and the buffer 24 is disposed inside the single-sided coating area 231d; in the direction opposite to the winding direction X, at least a portion of the single-sided coating area 231d extends beyond the second electrode 232.
[0148] Among them, the single-sided coating area 231d refers to the part of the inner surface and the outer surface of the first electrode 231 coated with the active material layer 231c; the double-sided coating area 231f refers to the part of the inner surface and the outer surface of the first electrode 231 coated with the active material layer 231c.
[0149] The inner side of the single-sided coating area 231d refers to the side of the single-sided coating area 231d facing into the central hole 23b1, while the outer side of the single-sided coating area 231d refers to the opposite side of the single-sided coating area 231d facing outward from the winding body 23b. The inner side of the single-sided coating area 231d is connected to the buffer member 24, thereby the outer side of the single-sided coating area 231d is coated with an active material layer 231c.
[0150] The single-sided coating area 231d and the double-sided coating area 231f are formed sequentially along the winding direction X, and the single-sided coating area 231d is formed upstream of the double-sided coating area 231f in the winding direction X; thus, during the winding operation, the single-sided coating area 231d can be wound into the innermost side of the wound body 23b, so that at least a portion of the single-sided coating area 231d will be located within or enclose the central hole 23b1.
[0151] Optionally, depending on the different lengths of the single-sided coating area 231d in the winding direction X, the single-sided coating area 231d can form a winding structure with multiple turns, such as half a turn, one turn, or one and a half turns, within the central hole 23b1 of the wound body 23b. Exemplarily, in some embodiments, the first electrode 231, the spacer 233, and the second electrode 232 are stacked sequentially, and in the winding direction X, the starting end of the second electrode 232 is approximately aligned with the starting end of the double-sided coating area 231f of the first electrode 231, or the starting end of the double-sided coating area 231f extends beyond the starting end of the second electrode 232 in a direction opposite to the winding direction X; thus, at least a portion of the single-sided coating area 231d can extend into or enclose the central hole 23b1.
[0152] With this configuration, the inner side of the single-sided coating area 231d is used to connect the buffer 24 to achieve a support effect, while the outer side of the single-sided coating area 231d can be coated with an active material layer 231c. Thus, the active material layer 231c on the single-sided coating area 231d can be fully utilized to improve the energy density of the battery cell 20.
[0153] Referring to Figures 4 and 6, in some embodiments, the width of the buffer 24 is less than or equal to the width of the wound body 23b in the winding axis Y direction, and the buffer 24 does not extend beyond the center hole 23b1.
[0154] Understandably, the first electrode 231, the second electrode 232, and the separator 233 are wound to form a wound body 23b. Therefore, the width of the wound body 23b is equal to the width of the first electrode 231 or the width of the second electrode 232.
[0155] In the winding axis Y direction, the buffer 24 does not extend out of the central hole 23b1; thus, in the winding axis Y direction, the end of the buffer 24 can be flush with the end of the wound body 23b, or a gap can be formed between the end of the buffer 24 and the end of the wound body 23b.
[0156] This configuration, which sets the buffer 24 to not extend beyond the center hole 23b1 in the winding axis Y direction, can effectively reduce the impact of the buffer 24 on the vision system recognition during the winding operation. It can also reduce the space occupied by the buffer 24 extending beyond the center hole 23b1, thereby reducing the impact on energy density.
[0157] Referring to Figures 4 and 6, in some embodiments, the wound body 23b has a width a and the buffer member 24 has a width b in the winding axis Y direction, wherein 0 ≤ a - b ≤ 2 mm.
[0158] Understandably, the width a of the wound body 23b can be wider than the width b of the buffer member 24, and the extent to which the width a of the wound body 23b is wider than the width b of the buffer member 24 does not exceed 2 millimeters (hereinafter, mm is used to represent millimeters). For example, the width a of the wound body 23b can be, but is not limited to, 0.1 mm, 0.5 mm, 1 mm, 1.5 mm, 2 mm, etc., wider than the width b of the buffer member 24.
[0159] Alternatively, the width a of the winding 23b can be the same as the width b of the buffer 24.
[0160] With this configuration, in the direction perpendicular to the winding direction X, the width of the buffer 24 can be set to be the same as the width of the winding body 23b to within the range of 2 mm narrower than the width of the winding body 23b; if the width of the buffer 24 is too wide, it may affect the winding process, and if the width of the buffer 24 is too narrow, it may cause stress marks to form on the first electrode 231 and the second electrode 232.
[0161] Please refer to Figures 4 and 6. In some embodiments, 0 ≤ a - b ≤ 1 mm.
[0162] By further limiting the difference in width between the winding body 23b and the buffer 24 to greater than or equal to zero and less than or equal to 1 mm, the probability of stress streaks forming on the first electrode 231 and the second electrode 232 can be further reduced.
[0163] Please refer to Figures 4, 9, or 11. In some embodiments, the buffer 24 has a compression ratio c, where 30% ≤ c ≤ 90%.
[0164] In this embodiment, the compression ratio of the buffer 24 is limited to greater than or equal to 30% and less than or equal to 90%; for example, the compression ratio of the buffer 24 may be, but is not limited to, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, etc.
[0165] With this setting, the compression ratio c of the buffer 24 is limited to greater than or equal to 30% and less than or equal to 90%. Within this range, the buffer 24 has a better support effect while having a lower impact on space occupation.
[0166] Please refer to Figures 4, 9, or 11. In some embodiments, 50% ≤ c ≤ 70%.
[0167] In this embodiment, the compression ratio c of the buffer 24 is limited to greater than or equal to 50% and less than or equal to 70%; for example, the compression ratio c of the buffer 24 may be, but is not limited to, 50%, 52%, 55%, 57%, 60%, 62%, 65%, 67%, 70%, etc.
[0168] With this setting, the compression rate c of the buffer 24 is further limited to greater than or equal to 50% and less than or equal to 70%, thereby further improving the support effect of the buffer 24 within this range and further reducing the impact of the buffer 24 on space occupation.
[0169] Please refer to Figures 4, 9, or 11. In some embodiments, the buffer 24 has a thickness d, 0.5 mm ≤ d ≤ 4 mm.
[0170] In this embodiment, the thickness d of the buffer 24 is limited to greater than or equal to 0.5 mm and less than or equal to 2 mm; for example, the compression ratio of the buffer 24 may be, but is not limited to, 0.5 mm, 0.8 mm, 1 mm, 1.2 mm, 1.4 mm, 1.5 mm, 1.7 mm, 1.9 mm, 2 mm, 2.3 mm, 2.5 mm, 2.8 mm, 3 mm, 3.2 mm, 3.5 mm, 3.8 mm, 4 mm, etc.
[0171] With this setting, the thickness d of the buffer 24 is limited to greater than or equal to 0.5 mm and less than or equal to 4 mm. Within this range, the buffer 24 has a better support effect while having a lower impact on space occupation.
[0172] Please refer to Figure 4, Figure 9, or Figure 11. 0.5mm ≤ d ≤ 2mm.
[0173] With this setting, the thickness d of the buffer 24 is further limited to greater than or equal to 0.5 mm and less than or equal to 2 mm. Within this range, the support effect of the buffer 24 can be further improved, and the space occupation of the buffer 24 can be further reduced.
[0174] Referring to Figure 5 or Figure 6, in some embodiments, at least one end of the buffer 24 has a chamfered structure 241 formed in the winding direction X.
[0175] In this embodiment, a chamfered structure 241 can be formed at one end of the buffer member 24 along the winding direction X, or a chamfered structure 241 can be formed at both opposite ends of the buffer member 24 along the winding direction X.
[0176] Optionally, the chamfer structure 241 includes, but is not limited to, a rounded corner structure, an inverted triangle structure, an inverted double triangle structure, an inverted arc structure, an inverted semi-circular arc structure, etc.
[0177] With this configuration, by providing a chamfered structure 241 on the buffer 24, the probability of the end of the buffer 24 being squeezed and indented by the first electrode 231 and the second electrode 232 during the cold pressing and shaping process of the winding body 23b can be effectively reduced.
[0178] Referring to Figures 4, 10, or 12, in some embodiments, the buffer 24 includes any one of a polypropylene buffer, a polyethylene buffer, an acrylic buffer, a polyester buffer, and a polycarbonate buffer.
[0179] With this configuration, any one of the following buffer components 24—polypropylene, polyethylene, plexiglass, polyester, and polycarbonate—can be used as the buffer component 24 to support the first electrode 231 and the second electrode 232.
[0180] Referring to Figures 4, 9, 11 and 15, in some embodiments, the buffer 24 is connected to the isolator 233.
[0181] Understandably, an adhesive layer can be coated on the surface of the buffer 24, so that when the buffer 24 is connected to the first electrode 231 and / or the second electrode 232, and the first electrode 231, the spacer 233 and the second electrode 232 are stacked in sequence and then wound, the buffer 24 can be fixedly connected to the spacer 233 by the adhesive layer.
[0182] For example, in some embodiments, the buffer 24 is fixedly connected to the surface of the first electrode 231, and an adhesive layer is provided on the side of the buffer 24 opposite to the first electrode 231, thereby the buffer 24 can also be connected to the separator 233 through the adhesive layer.
[0183] With this configuration, during the winding process of the first electrode 231, the second electrode 232, and the separator 233, the buffer 24 can also be tightly attached to the separator 233 through the adhesive layer, thereby effectively improving the stability of the buffer 24 and reducing the probability of the buffer 24 being misaligned during the winding process.
[0184] The battery cell 20 of this application embodiment will now be described in detail according to specific implementation methods.
[0185] Referring to Figures 1 to 8, in some embodiments, the battery cell 20 includes an electrode assembly 23, which includes a first electrode 231, a second electrode 232, and a separator 233 located between the first electrode 231 and the second electrode 232. In this embodiment, the first electrode 231 is a cathode electrode, and the second electrode 232 is an anode electrode. The cathode electrode has a blank foil area 231a and a coating area 231b sequentially formed along the winding direction X. The coating area 231b is used to coat the active material layer 231c, and a buffer member 24 is connected to the surface of the blank foil area 231a. The electrode, anode electrode, and separator 233 are wound along the winding direction X to form a wound body 23b, such that the blank foil area 231a is located within the central hole 23b1 of the wound body 23b. The buffer member 24 is connected to the blank foil area 231a, and thus the buffer member 24 is also located within the central hole 23b1. Thus, the buffer 24 can be connected to the empty foil area 231a within the central hole 23b1 and support the cathode and anode plates, thereby reducing the probability of the inner cathode and anode plates becoming loose. It can also be supported at the corners formed in the empty foil area 231a to increase the corner gap between the cathode and anode plates, thereby reducing the probability of the cathode and anode plates breaking brittlely at the corners.
[0186] Referring to Figures 11 to 14, in some embodiments, the battery cell 20 includes an electrode assembly 23. The electrode assembly 23 includes a first electrode 231, a second electrode 232, and a spacer 233 located between the first electrode 231 and the second electrode 232. The first electrode 231, the second electrode 232, and the spacer 233 are wound along the winding direction X to form a wound body 23b. In this embodiment, the first electrode 231 is an anode electrode, and the second electrode 232 is a cathode electrode. The anode electrode has a single-sided coating area 231d and a double-sided coating area 231f sequentially formed along the winding direction X, and the single-sided coating area 231d extends beyond the second electrode 232 in a direction opposite to the winding direction X; thus, at least a portion of the single-sided coating area 231d is wound to the innermost side of the wound body 23b, and the single-sided coating area 231d can be wound and enclosed to form a central hole 23b1. The buffer 24 is connected to the inner side of the single-sided coating area 231d, and the outer side of the single-sided coating area 231d is coated with an active material layer 231c; the buffer 24 can support the cathode and anode plates in the central hole 23b1, and can also support the cathode and anode plates at the corners to increase the corner gap, thereby reducing the probability of brittle fracture of the cathode and anode plates at the corners.
[0187] Referring to Figures 1 to 4, in a second aspect, embodiments of this application also provide a battery 100, including a housing 10 and a battery cell 20 as described above, wherein the battery cell 20 is housed within the housing 10.
[0188] The battery 100 provided in this application embodiment includes the aforementioned battery cell 20. Based on the superior reliability of the aforementioned battery cell 20, the battery 100 also has superior reliability.
[0189] Referring to Figures 1 and 2, in a third aspect, embodiments of this application also provide an electrical device, including a battery 100 as described above, the battery 100 being used to provide electrical energy.
[0190] The electrical device provided in this application embodiment is, for example, the vehicle 1000 described above. The electrical device includes the battery 100 described above, and based on the superior reliability of the battery 100, the electrical device also has superior reliability.
[0191] The above are merely preferred embodiments of this application and are not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.
Claims
1. A battery cell, characterized by: Comprising An electrode assembly comprising a first electrode tab, a second electrode tab, and a separator between the first electrode tab and the second electrode tab; the first electrode tab, the second electrode tab, and the separator are wound in a winding direction to form a wound body, a center of the wound body forms a center hole in a winding axis direction; the winding direction is perpendicular to the winding axis direction; And A buffer is at least partially disposed in the center hole, the buffer is connected to the first electrode tab and / or the second electrode tab.
2. The battery cell of claim 1, wherein: The first electrode tab sequentially forms an empty foil area and a coated area in the winding direction, the coated area is used to coat an active material layer; In a direction opposite to the winding direction, at least part of the empty foil area exceeds the second electrode tab, and the buffer is connected to the empty foil area.
3. The battery cell of claim 2, wherein: The empty foil area is wound to form at least one empty foil bending part in the winding direction; the buffer is connected to the empty foil bending part.
4. The battery cell of claim 3, wherein: The empty foil area is wound and alternately forms at least one empty foil flat part and at least one empty foil bending part in the winding direction; the buffer is connected to the empty foil flat part and the empty foil bending part.
5. The battery cell of claim 2, wherein: The empty foil area forms at least one empty foil flat part in the winding direction; the buffer is connected to the empty foil flat part.
6. The battery cell of any one of claims 2 to 5, wherein: The buffer comprises a first buffer part, and the first buffer part is disposed on the inner side of the empty foil area.
7. The battery cell of claim 6, wherein: The buffer comprises a second buffer part, and the second buffer part is disposed on the outer side of the empty foil area.
8. The battery cell of claim 7, wherein: The first buffer part and the second buffer part are oppositely disposed.
9. The battery cell of any one of claims 2 to 8, wherein: In the winding direction, the length o of the buffer is less than or equal to the length p of the empty foil area.
10. The battery cell of claim 2, wherein: In the winding direction, the end of the buffer and the starting end of the coated area form a gap.
11. The battery cell of any one of claims 1 to 10, wherein: The first electrode tab is a cathode electrode tab, and the second electrode tab is an anode electrode tab.
12. The battery cell of any one of claims 1 to 10, wherein: The first electrode tab is an anode electrode tab, and the second electrode tab is a cathode electrode tab.
13. The battery cell of claim 1, wherein: The first electrode tab comprises a single-sided coated area and a double-sided coated area sequentially disposed in the winding direction, the buffer is disposed on the inner side of the single-sided coated area; in a direction opposite to the winding direction, at least part of the single-sided coated area exceeds the second electrode tab.
14. The battery cell of any one of claims 1 to 13, wherein: In the winding axis direction, the width of the buffer is less than or equal to the width of the wound body, and the buffer does not protrude out of the center hole.
15. The battery cell of claim 14, wherein: In the winding axis direction, the wound body has a width a, and the buffer has a width b, wherein 0≤a-b≤2mm.
16. The battery cell of claim 15, wherein: 0≤a-b≤1mm.
17. The battery cell of any one of claims 1 to 16, wherein: The buffer has a compression rate c, and 30%≤c≤90%.
18. The battery cell of claim 17, wherein: 50％≤c≤70％。 19. The battery cell of any one of claims 1 to 18, wherein: The buffer has a thickness d, and 0.5mm≤d≤4mm.
20. The battery cell of claim 19, wherein: 0.5mm≤d≤2mm.
21. The battery cell of any one of claims 1 to 20, wherein: In the winding direction, at least one end of the buffer forms a chamfer structure.
22. The battery cell of any one of claims 1 to 21, wherein: The buffer comprises any one of a polypropylene buffer, a polyethylene buffer, an organic glass buffer, a polyester buffer, and a polycarbonate buffer.
23. The battery cell of any one of claims 1 to 22, wherein: The buffer is connected to the separator.
24. A battery, characterized by: A battery comprising a box and a battery cell as claimed in any one of claims 1 to 23, the battery cell is accommodated in the box.
25. An electrical device, comprising: A battery as claimed in claim 24, the battery is used to provide electric energy.