Battery cell, battery, and electrical apparatus

Abstract

A battery cell (30), comprising: an electrode assembly (10), a casing (31), and an end cover (32). The end cover (32) covers an open end (31o) of the casing (31). The electrode assembly (10) comprises a wound structure (100). The wound structure (100) is formed by winding a first electrode sheet (11), a second electrode sheet (12), and separators (131, 132), provided between the first electrode sheet (11) and the second electrode sheet (12), in a winding direction (r). An end portion region (14) of at least one side of at least one of the first electrode sheet (11) and the second electrode sheet (12) in the winding direction (r) is provided with a protective portion (20). The protective portion (20) has an inner protective layer (21) and an outer protective layer (22). The inner protective layer (21) has a first side edge (211) in the winding direction, and the outer protective layer (22) has a second side edge (221) in the winding direction. The first side edge (211) and the second side edge (221) are at least partially offset from each other in the winding direction (r).

Description

Battery cell, battery and electric device

[0001] Cross-reference to Related Applications

[0002] This application claims priority to Chinese Patent Application No. 202421964295.X, filed on August 14, 2024, entitled “Battery cell, battery and electric device”, the entire contents of which are incorporated herein by reference. TECHNICAL FIELD

[0003] The present disclosure relates to the technical field of batteries, in particular to a battery cell, a battery and an electric device. BACKGROUND

[0004] Secondary batteries, especially lithium ion batteries, have the advantages of high voltage, large specific energy, long cycle life, green and pollution-free, wide working temperature range and small self-discharge, and are widely used in portable electronic devices and large new energy electric vehicles, which have great significance in solving human environmental pollution and energy crisis. With the wide application of secondary batteries, the use reliability of the batteries has become a problem that users are closely concerned about. SUMMARY

[0005] In one aspect of the present disclosure, a battery cell is provided, comprising: an electrode assembly; a shell having a receiving cavity and an open end in communication with the receiving cavity, the receiving cavity being configured to accommodate the electrode assembly; and an end cover covering the open end; wherein the electrode assembly comprises: a first electrode sheet, a second electrode sheet and a separator disposed between the first electrode sheet and the second electrode sheet, the first electrode sheet, the second electrode sheet and the separator being wound in a winding direction and forming a wound structure; wherein at least one of the first electrode sheet and the second electrode sheet is provided with a protective portion at an end region of at least one side in the winding direction, the protective portion having an inner protective layer and an outer protective layer, the inner protective layer and the outer protective layer being respectively disposed on both sides of the end region in the thickness direction of the end region, along the winding direction, the inner protective layer having a first side edge located inside the edge of the end region, the outer protective layer having a second side edge located inside the edge of the end region, the first side edge and the second side edge being at least partially staggered with each other in the winding direction.

[0006] The protective portion is arranged at the end region of the pole piece, and the protective portion can be used to disperse and buffer the shearing stress of the pole piece adjacent to the inner and outer layers of the end region of the pole piece. By at least partially staggering the first side edge of the inner protective layer and the second side edge of the outer protective layer in the winding direction, the superposition of the inner and outer steps of the inner protective layer and the outer protective layer on the pole piece can be minimized or eliminated, and the superposition of the shearing stress formed on the pole piece at the step position when the electrode assembly is cyclically expanded can be minimized or eliminated, thereby reducing the risk of cracks or even fractures of the pole piece caused by excessive stress at the step position, and further improving the reliability of the battery cell.

[0007] In some embodiments, the first side edge is further away from the edge of the end region in the winding direction than the second side edge.

[0008] The first side edge is further away from the edge of the end region in the winding direction than the second side edge, which means that in the winding direction (corresponding to the length direction of the pole piece in the unfolded state), the minimum distance between the first side edge and the edge is greater than the minimum distance between the second side edge and the edge. This structure can form pole piece surfaces with different shielding ranges at the end region of the pole piece provided with the protective portion, wherein the less shielded outer pole piece surface can obtain a relatively larger effective active area, which is beneficial to improve the energy density of the electrode assembly, and the inner protective layer with a larger shielding range can more effectively disperse the extrusion force when the battery assembly is cyclically expanded, thereby reducing the risk of damage to the pole piece caused by the extrusion force.

[0009] In some embodiments, the first side edge includes a first sub-side edge and a second sub-side edge, the first sub-side edge is further away from the edge of the end region in the winding direction than the second side edge, and the second sub-side edge is closer to the edge of the end region in the winding direction than the second side edge.

[0010] The first sub-side edge of the first side edge is further away from the edge than the corresponding part of the second side edge, and the second sub-side edge is closer to the edge than the corresponding part of the second side edge, which means that the first side edge and the second side edge can intersect. This structure can more flexibly adjust the shielding degree of the inner and outer surfaces of the pole piece, thereby reducing the shearing stress while meeting the requirements of dispersing the extrusion force, improving the energy density of the battery assembly, and the like. In addition, by this structure, the coverage ranges of the inner protective layer and the outer protective layer on the inner and outer surfaces of the pole piece are basically the same, so that the bonding strength of the inner protective layer and the outer protective layer to the inner and outer surfaces of the pole piece is close, and the risk of easy detachment of the single protective layer due to the large difference in bonding strength is reduced.

[0011] In some embodiments, at least one of the inner protective layer and the outer protective layer covers at least part of the edge of the end region.

[0012] The protective portion can cover part or all of the edge by the inner protective layer or the outer protective layer, or by the inner protective layer and the outer protective layer together, so that the burrs of the end region of the pole piece caused by cutting and the like can be isolated from the separator by the protective portion, thereby reducing the risk of the burrs piercing the separator and causing short circuit between the pole pieces of different polarities.

[0013] In some embodiments, both the inner protective layer and the outer protective layer extend beyond the end region in the width direction of the end region, which is perpendicular to the winding direction.

[0014] By extending both the inner protective layer and the outer protective layer beyond the end region in the width direction of the end region, the edge can be entirely wrapped, so that the burrs of the edge can be isolated from the separator, thereby more effectively reducing the risk of the burrs piercing the separator and causing short circuit between the pole pieces of different polarities.

[0015] In some embodiments, the protective portion includes an extension segment, which is located outside the edge of the end region in the winding direction and connected to at least one of the inner protective layer and the outer protective layer.

[0016] By providing the extension segment, the isolation effect of at least one of the inner protective layer and the outer protective layer on the edge can be facilitated, and the risk of the inner protective layer and the outer protective layer moving relative to the surface of the pole piece and losing the isolation effect on the edge can be reduced. In addition, the extension segment can also support the separator to a certain extent.

[0017] In some embodiments, the protective portion is arranged at the beginning end of at least one of the first pole piece and the second pole piece in the winding direction, and the extension segment is wound for N1 turns, where N1≥1.

[0018] The extension segment of the protective portion arranged at the beginning end of at least one of the first pole piece and the second pole piece in the winding direction r is arranged to be wound for not less than one turn, which can effectively enhance the inner turn support strength of the winding structure, thereby reducing the risk of collapse of the inner turns.

[0019] In some embodiments, the protective portion is arranged at the beginning end of at least one of the first pole piece and the second pole piece in the winding direction, and the extension segment is wound for N1 turns, where 0<N1<1.

[0020] The extension of the protection part provided at the beginning end of at least one of the first pole piece and the second pole piece in the winding direction r is provided to be wound for a length less than one turn, which is beneficial for saving the material use of the protection part.

[0021] In some embodiments, the part of the separator located outside the edge of the beginning end in the winding direction is wound for N1 turns.

[0022] By winding the part of the separator located outside the edge of the beginning end for N1 turns, the separator and the extension of the protection part are jointly wound for N1 turns outside the edge of the beginning end, so that the support effect of the extension on the inner turns of the wound structure is achieved, the support strength of the inner turns of the wound structure is enhanced, and the risk of collapse of the inner turns is reduced.

[0023] In some embodiments, the part of the separator located outside the edge of the beginning end in the winding direction is wound for N2 turns, and N2>N1.

[0024] By winding the part of the separator located outside the edge of the beginning end for N2 turns, the winding difficulty is reduced and the manufacturing process is simplified beyond the N1 turns wound by the extension of the protection part.

[0025] In some embodiments, the protection part is provided at the end of at least one of the first pole piece and the second pole piece in the winding direction, and the extension is wound for N3 turns, where 0<N3<1.

[0026] The extension of the protection part provided at the end of at least one of the first pole piece and the second pole piece in the winding direction r is provided to be wound for a length less than one turn, which is beneficial for saving the material use of the protection part. In addition, the shorter extension located in the outer turns can reduce the volume of the electrode assembly, thereby facilitating the improvement of the energy density of the electrode assembly.

[0027] In some embodiments, the inner side protection layer is bonded to the inner side surface of the end region in the thickness direction of the end region, and the outer side protection layer is bonded to the outer side surface of the end region in the thickness direction of the end region.

[0028] The inner side protection layer and the outer side protection layer are respectively bonded to the inner and outer side surfaces of the end region by bonding, which can form a stable and reliable bonding effect with the pole piece, reduce the risk of falling off, and is also more convenient in assembly relative to the pole piece.

[0029] In some embodiments, the protection part includes two single-sided adhesive tapes respectively forming the inner side protection layer and the outer side protection layer, and the adhesive layers of the parts of the two single-sided adhesive tapes protruding from the edges of the end region are bonded to each other.

[0030] The two single-sided tapes are respectively used to form the inner protective layer and the outer protective layer of the protective part, which can simplify the arrangement of the protective part at the end area of the first or second pole piece, and the single-sided tapes are easy to obtain and have shapes and sizes that can meet the design requirements, thereby facilitating the reduction of the preparation difficulty of the electrode assembly and the improvement of the processing efficiency of the electrode assembly. Moreover, the adhesive layers of the two single-sided tapes that protrude from opposite portions of the edge of the end area are bonded to each other, which can form a tighter bonding force between the protective part and the end area and reduce the risk of falling off.

[0031] In some embodiments, the protective part includes a single-sided tape that is folded to form the inner protective layer and the outer protective layer, and the adhesive layers of opposite portions of the single-sided tape that protrude from the edge of the end area are bonded to each other.

[0032] The single-sided tape that is folded to form the inner protective layer and the outer protective layer of the protective part can simplify the arrangement of the protective part at the end area of the first or second pole piece, and the single-sided tape is easy to obtain and has a shape and size that can meet the design requirements, thereby facilitating the reduction of the preparation difficulty of the electrode assembly and the improvement of the processing efficiency of the electrode assembly. Moreover, the adhesive layers of opposite portions of the single-sided tape that protrude from the edge of the end area are bonded to each other, which can form a tighter bonding force between the protective part and the end area and reduce the risk of falling off.

[0033] In one aspect of the present disclosure, a battery is provided, including the aforementioned battery cell.

[0034] The battery using the aforementioned battery cell embodiment can obtain better use reliability.

[0035] In one aspect of the present disclosure, a power consumption device is provided, including the aforementioned battery.

[0036] The power consumption device using the aforementioned battery embodiment can obtain better use reliability. BRIEF DESCRIPTION OF DRAWINGS

[0037] In order to more clearly illustrate the technical solutions of the embodiments of the present disclosure, the drawings needed to be used in the embodiments of the present disclosure will be briefly introduced as follows. Obviously, the drawings described below are only some embodiments of the present disclosure, and other drawings can also be obtained by those skilled in the art without creative labor on the basis of the drawings.

[0038] With reference to the drawings, the present disclosure can be more clearly understood according to the following detailed description.

[0039] FIG. 1 is a structural schematic diagram of some embodiments of a power consumption device according to the present disclosure;

[0040] FIG. 2 is an exploded schematic diagram of some embodiments of a battery according to the present disclosure;

[0041] FIG. 3 is an exploded schematic view of a battery cell according to some embodiments of the present disclosure;

[0042] FIG. 4 is a cross-sectional schematic view of a winding structure of an electrode assembly in a battery cell embodiment according to the present disclosure;

[0043] FIG. 5 is a schematic view of the first and second electrode sheets in an unfolded state in the embodiment shown in FIG. 4;

[0044] FIG. 6A is a schematic view of a guard provided at an electrode sheet end region in some embodiments of a battery cell according to the present disclosure;

[0045] FIG. 6B is a schematic view of FIG. 6A from a top perspective;

[0046] FIGS. 6C and 6D are schematic views of two other guards provided at an electrode sheet end region, respectively;

[0047] FIG. 6E is an exploded schematic view of FIG. 6A;

[0048] FIG. 7A is a schematic view of yet another guard provided at an electrode sheet end region;

[0049] FIG. 7B is an exploded schematic view of FIG. 7A;

[0050] FIGS. 8A, 9A, 10A, 11A, 12A, 13A, 14A, and 15A are cross-sectional schematic views of winding structures of electrode assemblies according to other embodiments of a battery cell of the present disclosure, respectively;

[0051] FIGS. 8B, 9B, 10B, 11B, 12B, 13B, 14B, and 15B are schematic views of the first and second electrode sheets in an unfolded state in the embodiments shown in FIGS. 8A, 9A, 10A, 11A, 12A, 13A, 14A, and 15A, respectively.

[0052] It should be understood that the dimensions of the various parts shown in the drawings are not necessarily shown to scale. In addition, like or similar reference numerals are used to indicate like or similar parts.

[0053] Explanation of Reference Numerals: 10 - electrode assembly; 100 - wound structure; 11 - first tab; 12 - second tab; 11a, 12a - initial end; 11b, 12b - terminal end; 131, 132 - spacer; 14 - end region; 141 - edge; 15 - outer tape; 20 - guard portion; 20a, 20a' - first initial end guard portion; 20b, 20b' - second initial end guard portion; 20c - first terminal end guard portion; 20d - second terminal end guard portion; 21 - inner guard layer; 21g - inner guard adhesive layer; 211 - first side edge; 211a - first sub side edge; 211b - second sub side edge; 22 - outer guard layer; 22g - outer guard adhesive layer; 221 - second side edge; 23 - extension section; 23g - extension section adhesive layer; 231 - first extension section tape base material; 231g - first extension section adhesive layer; 232 - second extension section tape base material; 232g - second extension section adhesive layer; 30 - battery cell; 31 - case; 31c - accommodation cavity; 31o - open end; 32 - end cap; 33 - current collector; 40 - battery; 41 - box body; 42 - box cover; 50 - vehicle; r - winding direction; rp - reference plane. DETAILED DESCRIPTION

[0054] Various exemplary embodiments of the present disclosure will now be described in detail with reference to the accompanying drawings. The description of the exemplary embodiments is merely illustrative in nature and is in no way intended to limit the disclosure, its application or uses, except as described by the appended claims. The present disclosure can be implemented in numerous different forms, as is desired for specific applications; the embodiments described herein are merely illustrative and not restrictive.

[0055] In the description of the disclosure, it needs to be explained that, unless otherwise specified, the meaning of "a plurality of" is more than two. The "first", "second" and similar words used in the disclosure do not represent any order, quantity or importance, but are only used to distinguish different parts. "Include" or "contain" and similar words mean that the elements before the word cover the elements listed after the word, and do not exclude the possibility of also covering other elements. The "upper", "lower", "left", "right", "inner", "outer" indicated orientation or position relationship is only for the convenience of describing the disclosure and simplifying the description, and does not indicate or imply that the indicated device or element must have a particular orientation, be constructed and operated in a particular orientation, so it cannot be understood as a limitation on the disclosure. When the absolute position of the described object changes, the relative positional relationship may also change accordingly. "Vertical" is not strictly vertical, but within the allowable error range. "Parallel" is not strictly parallel, but within the allowable error range.

[0056] In the disclosure, it also needs to be explained that, unless otherwise specifically defined and limited, the terms "mount", "connect", "connect" should be broadly understood. When it is described that a specific device is located between the first device and the second device, there can be no intermediate device between the specific device and the first device or the second device. When it is described that a specific device is connected to other devices, the specific device can be directly connected to the other devices without an intermediate device, or can not be directly connected to the other devices with an intermediate device. For example, the connection can be a fixed connection, or a detachable connection, or an integral connection.

[0057] All terms used in the disclosure (including technical terms or scientific terms) have the same meaning as understood by those skilled in the art to which the disclosure belongs, unless otherwise specifically defined. It should also be understood that terms defined in, such as general dictionaries, should be interpreted to have meanings consistent with their meanings in the context of the relevant art, and should not be interpreted in an idealized or extremely formalized sense, unless specifically defined here.

[0058] The technology, method and equipment known to those skilled in the relevant art can not be discussed in detail, but in appropriate cases, the technology, method and equipment should be considered as part of the specification.

[0059] In some related art electrode assemblies, the tab is provided with a tape portion of insulating material at the beginning and the end, and the tape portion is aligned and pasted on the inner and outer surfaces of the tab.

[0060] It is found through research that the alignment of the adhesive tape and the electrode sheet forms an inside-outside step superposition between the adhesive tape and the electrode sheet. When the electrode assembly is cyclically expanded, the shear stress formed on the electrode sheet is also superimposed at the step position, and there is a risk that the electrode sheet will crack or even fracture due to excessive stress at the step position, thereby affecting the reliability of the battery cell and further affecting the cycle life and performance of the battery.

[0061] Therefore, the battery cell, the battery and the electric device provided by the embodiments of the present disclosure can improve the reliability of the battery cell.

[0062] In one aspect of the present disclosure, a battery cell is provided, comprising: an electrode assembly; a shell having a receiving cavity and an open end in communication with the receiving cavity, the receiving cavity being configured to accommodate the electrode assembly; and an end cover covering the open end; wherein the electrode assembly comprises: a first electrode sheet, a second electrode sheet and a separator disposed between the first electrode sheet and the second electrode sheet, the first electrode sheet, the second electrode sheet and the separator being wound in a winding direction and forming a wound structure; wherein at least one of the first electrode sheet and the second electrode sheet is provided with a protective portion at an end region of at least one side in the winding direction, the protective portion having an inside protective layer and an outside protective layer, the inside protective layer and the outside protective layer being respectively arranged on both sides of the end region in a thickness direction of the end region, along the winding direction, the inside protective layer has a first side edge located inside an edge of the end region, the outside protective layer has a second side edge located inside the edge of the end region, and the first side edge and the second side edge are at least partially staggered with each other in the winding direction.

[0063] The protective portion is arranged at the end region of the electrode sheet, and the protective portion can be used to disperse and buffer the shear stress of the electrode sheet adjacent to the inside and outside layers of the end region of the electrode sheet, and by at least partially staggering the first side edge of the inside protective layer and the second side edge of the outside protective layer of the protective portion in the winding direction, the inside and outside steps of the inside protective layer and the outside protective layer on the electrode sheet can be reduced or eliminated as much as possible, and the shear stress formed on the electrode sheet when the electrode assembly is cyclically expanded can be prevented from being superimposed at the step position, thereby reducing the risk of cracks or even fractures of the electrode sheet due to excessive stress at the step position, and further improving the reliability of the battery cell.

[0064] In the embodiments of the present disclosure, the battery cell can be a secondary battery, which refers to a battery cell that can be used continuously by activating the active material through charging after discharging. The battery cell can be a lithium ion battery, a sodium ion battery, a sodium lithium ion battery, a lithium metal battery, a sodium metal battery, a lithium-sulfur battery, a magnesium ion battery, a nickel-hydrogen battery, a nickel-cadmium battery, a lead-acid battery, etc. The embodiments of the present disclosure are not limited thereto. The battery cell can be in the shape of a cylinder, a flat body, a cuboid, or other shapes, etc. The embodiments of the present disclosure are not limited thereto. The battery cell is generally classified into a cylindrical battery cell, a square battery cell, and a soft-pack battery cell according to the packaging method, and the embodiments of the present disclosure are not limited thereto.

[0065] The battery cell of the embodiments of the present disclosure can be applied to various types of batteries. The battery referred to herein refers to a single physical module including one or more battery cells to provide higher voltage and capacity.

[0066] In some embodiments, the battery can include a case and a battery module, the case being configured to provide a space for accommodating the battery module, and the battery module being installed in the case. The case can be made of metal. The battery module can include a plurality of battery cells connected in series, in parallel, or in a mixed connection. The battery cell is the smallest unit that constitutes the battery. The battery cell includes an electrode assembly capable of electrochemical reaction.

[0067] In some embodiments, the battery can include a case and a battery cell, and the battery cell is accommodated in the case.

[0068] In some embodiments, the case can be part of the chassis structure of the vehicle. For example, part of the case can be at least part of the floor of the vehicle, or part of the case can be at least part of the cross beam and the longitudinal beam of the vehicle.

[0069] In some embodiments, the battery can be an energy storage device. The energy storage device includes an energy storage container, an energy storage cabinet, etc.

[0070] The battery of the embodiments of the present disclosure can be applied to various types of electric devices using batteries. The electric device can be a mobile phone, a portable device, a notebook computer, an electric vehicle, an electric automobile, a ship, a spacecraft, an electric toy, and an electric tool, etc. For example, the spacecraft includes an airplane, a rocket, a space shuttle, a spacecraft, etc. The electric toy includes a stationary or mobile electric toy, such as a game console, an electric automobile toy, an electric ship toy, and an electric airplane toy, etc. The electric tool includes a metal cutting electric tool, a grinding electric tool, an assembly electric tool, and a railway electric tool, such as a power drill, a power grinder, a power wrench, a power screwdriver, an electric hammer, an impact drill, a concrete vibrator, and an electric planer. The embodiments of the present disclosure do not particularly limit the above-mentioned electric devices. The battery can be used for power supply of the electric device, such as an electric vehicle, to provide power for control or driving.

[0071] FIG. 1 is a structural schematic diagram of some embodiments of an electric device according to the present disclosure. For convenience, the electric device is exemplified as a vehicle. The vehicle 50 can be a fuel vehicle, a gas vehicle, or a new energy vehicle, which can be a pure electric vehicle or a hybrid electric vehicle, etc. The battery 40 can be arranged at the bottom, the front, or the rear of the vehicle 50.

[0072] The battery 40 can be used for power supply of the vehicle 50. For example, the battery 40 can be used as an operating power source of the vehicle 50, for example, for the circuit system of the vehicle 50, such as for the starting, navigation, and working power demand of the vehicle 50. The battery 40 can not only be used as an operating power source of the vehicle 50, but also be used as a driving power source of the vehicle 50, to replace or partially replace the fuel or natural gas to provide driving force for the vehicle 50.

[0073] FIG. 2 is an exploded schematic diagram of some embodiments of a battery according to the present disclosure. FIG. 3 is an exploded schematic diagram of some embodiments of a battery cell according to the present disclosure. Referring to FIG. 2, in some embodiments, the battery 40 includes a box 41, a box cover 42, and one or more battery cells 30 arranged in the box 41. The box 41 can provide functions such as cooling, sealing, and impact protection for the battery cells 30 while containing the battery cells 30, and can avoid the adverse effects of liquid or other foreign matter on the charging and discharging or safety of the battery cells 30. The box cover 42 can be arranged at the end of the box 41 to close the box 41. The battery cells 30 are electrically connected to each other, such as in series, parallel, or mixed connection, to achieve the required electrical performance parameters of the battery 40. The battery cells 30 can be arranged in one or more rows in the box according to the needs.

[0074] In some embodiments, the battery cells 30 of the battery 40 can be arranged along at least one of the length direction and the width direction of the box. According to actual needs, at least one row or column of battery cells 30 can be arranged. According to the needs, one or more layers of battery cells 30 can also be arranged in the height direction of the battery 40.

[0075] In some embodiments, a plurality of battery cells 30 can be connected in series or parallel or mixed connection to form a battery module, and then a plurality of battery modules are connected in series or parallel or mixed connection to form an integral whole and are contained in the box 41. In other embodiments, all battery cells 30 are directly connected in series or parallel or mixed connection, and the integral whole formed by all battery cells 30 is contained in the box. The electrode terminals of the battery cells 30 can be electrically connected to adjacent battery cells 30 through busbars.

[0076] FIG. 4 is a cross-sectional schematic view of a winding structure of an electrode assembly in a battery cell embodiment according to the present disclosure. FIG. 5 is a schematic view of a first electrode tab and a second electrode tab in an unfolded state in the embodiment shown in FIG. 4. Referring to FIGS. 3-5, an embodiment of the present disclosure provides a battery cell 30 including an electrode assembly 10, a housing 31, and an end cap 32. The housing 31 has a receiving cavity 31c configured to receive the electrode assembly 10 and an open end 31o in communication with the receiving cavity 31c. The end cap 32 covers the open end 31o. The electrode assembly 10 includes a first electrode tab 11, a second electrode tab 12, and separators 131, 132 disposed between the first electrode tab 11 and the second electrode tab 12, the first electrode tab 11, the second electrode tab 12, and the separators 131, 132 being wound in a winding direction r and forming a winding structure 100. At least one of the first electrode tab 11 and the second electrode tab 12 has a protective portion 20 at an end region 14 on at least one side in the winding direction r, the protective portion 20 having an inner protective layer 21 and an outer protective layer 22, the inner protective layer 21 and the outer protective layer 22 being disposed on both sides of the end region 14 in a thickness direction of the end region 14, respectively, the inner protective layer 21 having a first side edge 211 inside an edge 141 of the end region 14 in the winding direction r, the outer protective layer 22 having a second side edge 221 inside the edge 141 of the end region 14 in the winding direction r, the first side edge 211 and the second side edge 221 being at least partially offset from each other in the winding direction r.

[0077] The receiving cavity 31c can be configured to receive the electrode assembly 10 and can contain an electrolyte. At least one end of the housing 31 can be configured to be open to provide the open end 31o for the end cap 32. The open end 31o can allow the electrode assembly 10 to enter the receiving cavity 31c through the open end 31o when the battery cell is installed. The shape of the housing 31 can be determined according to the shape of the electrode assembly or assemblies 10 received in the receiving cavity 31c, for example, the shape of the housing 31 is a hollow cuboid or a hollow square or a hollow cylinder. The housing 31 can be made of a metal (e.g., aluminum, aluminum alloy, etc.) and / or a non-metallic material (plastic) having a certain hardness and strength.

[0078] The battery cell 30 includes the electrode assembly 10, the end cap 32, and the housing 31, and further includes an electrolyte. The battery cell 30 can further include a current collector 33. The current collector 33 is located between the tab of the electrode assembly 10 and the electrode terminal on the end cap 32 and can be fixedly connected to the tab and the electrode terminal, respectively, by welding.

[0079] The end cover 32 is arranged at the open end 31o of the housing 31 to close the open end 31o and form a sealed accommodation cavity 31c with the housing 31 to accommodate the electrode assembly 10. The end cover 32 can be made of metal (e.g., aluminum, aluminum alloy, etc.) and / or non-metallic material (plastic) having certain hardness and strength. The end cover 32 can be fixedly connected with the housing 31 by welding, bonding or through a connector, etc. The end cover 32 can be provided with some functional components, such as a liquid injection mechanism, a pressure relief mechanism, etc.

[0080] The first and second electrode tabs 11 and 12 are opposite in polarity. In some embodiments, the first electrode tab 11 is a negative electrode tab and the second electrode tab 12 is a positive electrode tab. In other embodiments, the first electrode tab 11 is a positive electrode tab and the second electrode tab 12 is a negative electrode tab. During charging and discharging of the battery cell, active ions (e.g., lithium ions) are intercalated and deintercalated between the positive and negative electrode tabs. The separator is arranged between the positive and negative electrode tabs to prevent short circuiting of the positive and negative electrodes while allowing the active ions to pass through.

[0081] In some embodiments, the positive electrode tab can include a positive electrode current collector substrate and a positive electrode active material layer arranged on at least one surface of the positive electrode current collector substrate.

[0082] As an example, the positive electrode current collector substrate has two surfaces opposite in its own thickness direction, and the positive electrode active material layer is arranged on either or both of the two opposite surfaces of the positive electrode current collector substrate.

[0083] As an example, the positive electrode current collector substrate can be a metal foil or a composite current collector. For example, as a metal foil, silver surface treated aluminum or stainless steel, stainless steel, copper, aluminum, nickel, carbon, carbon, nickel or titanium, etc. can be used. The composite current collector can include a polymer material base layer and a metal layer. The composite current collector can be formed by arranging a metal material (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0084] As an example, the positive active material layer can include at least one of a lithium-containing phosphate, a lithium transition metal oxide, and a modified compound of each thereof. However, the disclosure is not limited to these materials, and other conventional materials that can be used as a battery positive active material layer can also be used. These positive active material layers can be used alone only one or two or more can be used in combination. Among them, examples of the lithium-containing phosphate can include, but are not limited to, at least one of lithium iron phosphate (such as LiFeP04(also can be referred to as LFP)), a composite of lithium iron phosphate and carbon, lithium manganese phosphate (such as LiMnPO4), a composite of lithium manganese phosphate and carbon, lithium manganese iron phosphate, a composite of lithium manganese iron phosphate and carbon. Examples of the lithium transition metal oxide can include, but are not limited to, at least one of lithium cobalt oxide (such as LiCoO2), lithium nickel oxide (such as LiNiO2), lithium manganese oxide (such as LiMnO2, LiMn2O4), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide (such as LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2(also can be referred to as NCM 333 ), LiNi 0.5 Co 0.2 Mn 0.3 O2(also can be referred to as NCM 523 ), LiNi 0.5 Co 0.25 Mn 0.25 O2(also can be referred to as NCM 211 ), LiNi 0.6 Co 0.2 Mn 0.2 O2(also can be referred to as NCM 622 ), LiNi 0.8 Co 0.1 Mn 0.1 O2(also can be referred to as NCM 811 ), lithium nickel cobalt aluminum oxide (such as LiNi 0.85 Co 0.15 Al 0.05 O2), and modified compounds thereof, etc.

[0085] In some embodiments, the negative electrode tab can include a negative current collector substrate.

[0086] As an example, the negative current collector substrate can employ a metal foil, a foamed metal, or a composite current collector. For example, as a metal foil, silver surface-treated aluminum or stainless steel, stainless steel, copper, aluminum, nickel, a carbon electrode, or the like can be employed. The foamed metal can be foamed nickel, foamed copper, foamed aluminum, foamed alloy, or foamed carbon, or the like. The composite current collector can include a polymer material base layer and a metal layer. The composite current collector can be formed by applying a metal material (copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy, or the like) on a polymer material base substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, or the like).

[0087] In some embodiments, the negative electrode tab can include a negative current collector substrate and a negative active material layer disposed on at least one surface of the negative current collector substrate.

[0088] As an example, the negative current collector substrate has two surfaces opposite in the thickness direction thereof, and the negative active material layer is disposed on either one or both of the two opposite surfaces of the negative current collector substrate.

[0089] As an example, the negative active material layer can employ a negative active material layer for a battery cell known in the art. As an example, the negative active material layer can include at least one of artificial graphite, natural graphite, soft carbon, hard carbon, a silicon-based material, a tin-based material, and lithium titanate, or the like. The silicon-based material can be selected from at least one of elemental silicon, a silicon oxide compound, a silicon-carbon composite, a silicon-nitrogen composite, and a silicon alloy. The tin-based material can be selected from at least one of elemental tin, a tin oxide compound, and a tin alloy. However, the present disclosure is not limited to these materials, and other conventional materials that can be used as a battery negative active material layer can also be used. These negative active material layers can be used alone or in combination of two or more.

[0090] In some embodiments, the material of the positive current collector substrate can be aluminum, and the material of the negative current collector substrate can be copper.

[0091] In some embodiments, the separator is a separator film. The present disclosure does not have a particular limitation on the type of separator film, and any known porous structure separator film having good chemical stability and mechanical stability can be used.

[0092] As an example, the main material of the separator film can be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene, polyvinylidene fluoride, and ceramic. The separator film can be a single layer film or a multi-layer composite film, and is not particularly limited. When the separator film is a multi-layer composite film, the materials of the respective layers can be the same or different, and are not particularly limited. The separator can be a separate component located between the positive electrode sheet and the negative electrode sheet, or can be attached to the surface of the positive electrode sheet and / or the surface of the negative electrode sheet while being located between the positive electrode sheet and the negative electrode sheet.

[0093] In some embodiments, the separator is a solid-state electrolyte. The solid-state electrolyte is disposed between the positive electrode sheet and the negative electrode sheet, and functions to transport ions and separate the positive and negative electrodes.

[0094] In some embodiments, the battery cell further includes an electrolyte that functions to conduct ions between the positive and negative electrodes. The type of electrolyte is not particularly limited by the present disclosure and can be selected as desired. The electrolyte can be liquid, gel, or solid.

[0095] As an example, the liquid electrolyte includes an electrolyte salt and a solvent.

[0096] In some embodiments, the electrolyte salt can be selected from at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bisfluorosulfonylimide, lithium bis-trifluoromethanesulfonylimide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluoro oxalate borate, lithium di-oxalate borate, lithium difluoro di-oxalate phosphate, and lithium tetrafluoro oxalate phosphate.

[0097] In some embodiments, the solvent can be selected from at least one of ethylene carbonate, propylene carbonate, methyl ethyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, butylene carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, butanedisulfone, methyl ethyl sulfone, and diethyl sulfone. The solvent can also be an ether-based solvent. The ether-based solvent can include one or more of ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, 1,3-dioxolane, tetrahydrofuran, methyl tetrahydrofuran, diphenyl ether, and a crown ether.

[0098] As an example, the gel electrolyte includes a polymer as a backbone network of the electrolyte, in combination with an ionic liquid-lithium salt.

[0099] As an example, the solid-state electrolyte includes a polymer solid-state electrolyte, an inorganic solid-state electrolyte, and a composite solid-state electrolyte.

[0100] As an example, the polymer solid-state electrolyte can be a polyether (polyethylene oxide), a polysiloxane, a polycarbonate, a polyacrylonitrile, a polyvinylidene fluoride, a polymethyl methacrylate, a single-ion polymer, a polyionic liquid-lithium salt, a cellulose, or the like.

[0101] As an example, the inorganic solid-state electrolyte can be one or more of an oxide solid-state electrolyte (crystalline perovskite, sodium superionic conductor, garnet, amorphous LiPON thin film), a sulfide solid-state electrolyte (crystalline lithium superionic conductor (lithium germanium phosphorous sulfide, argyrodite), amorphous sulfide), and a halide solid-state electrolyte, a nitride solid-state electrolyte, and a hydride solid-state electrolyte.

[0102] As an example, the composite solid-state electrolyte is formed by adding an inorganic solid-state electrolyte filler to a polymer solid-state electrolyte.

[0103] In some embodiments, the electrode assembly includes a main body portion. The main body portion can be a main body portion of a wound structure in which a positive electrode sheet, a negative electrode sheet, and a separator are wound. The positive electrode sheet and the negative electrode sheet can each be provided with one or more.

[0104] Referring to FIG. 4, in some embodiments, one first electrode sheet 11 and one second electrode sheet 12 are separated and overlapped by two separators 131, 132 (shown by dotted lines) and wound in a winding direction r to form a wound structure 100. The separators at the outermost layer of the wound structure 100 are fixed by being adhered by an outer layer tape 15. In other embodiments, a plurality of positive electrode sheets, a plurality of negative electrode sheets, and a plurality of separators are separated and overlapped and wound to form a wound structure.

[0105] In some embodiments, the main body portion can have a cylindrical shape, a flat shape, or a multi-prism shape, or the like. The end portion of the main body portion can be provided with a first tab and a second tab. The first tab can be formed by cutting or trimming the current collector substrate of the first electrode sheet, or can be connected to the side of the current collector substrate of the first electrode sheet by welding. The second tab can be formed by cutting or trimming the current collector substrate of the second electrode sheet, or can be connected to the side of the current collector substrate of the second electrode sheet by welding.

[0106] For embodiments in which the first electrode sheet is a positive electrode sheet and the second electrode sheet is a negative electrode sheet, the first electrode sheet includes a positive electrode tab as the first tab, and the second electrode sheet includes a negative electrode tab as the second tab. For embodiments in which the first electrode sheet is a negative electrode sheet and the second electrode sheet is a positive electrode sheet, the first electrode sheet includes a negative electrode tab as the first tab, and the second electrode sheet includes a positive electrode tab as the second tab.

[0107] In FIG. 4 and FIG. 5, the end region of the initial winding section of the first tab 11 is the start end 11a, and the end region of the final winding section of the first tab 11 is the end end 11b along the winding direction r; the end region of the initial winding section of the second tab 12 is the start end 12a, and the end region of the final winding section of the second tab 12 is the end end 12b along the winding direction r. Here, the end region of a tab on one side in the winding direction r refers to the region of the tab from the side end surface to a preset distance (e.g., 10 cm, 15 cm, or 20 cm, etc.) in the winding direction r (or the opposite direction of the winding direction r).

[0108] The guard portion 20 provided at the start end 11a of the first tab 11 is a first start end guard portion 20a, the guard portion 20 provided at the end end 11b of the first tab 11 is a first end end guard portion 20c, the guard portion 20 provided at the start end 12a of the second tab 12 is a second start end guard portion 20b, and the guard portion 20 provided at the end end 12b of the second tab 12 is a second end end guard portion 20d.

[0109] For the convenience of understanding, FIG. 5 shows the unfolded state of the first tab 11 and the second tab 12. In FIG. 5, the two ends of the first tab 11 and the second tab 12 in the winding direction r and the partial length close to the two ends are shown, and the middle part is omitted by a dotted line. In order to distinguish, the first tab 11 and the second tab 12 are filled with different patterns respectively.

[0110] FIG. 6A is a schematic diagram of the guard portion provided at the end region of the tab according to some embodiments of the battery cell of the present disclosure.

[0111] Referring to FIG. 5, the guard portion 20 can be provided at at least one of the start end and the end end of at least one of the first tab 11 and the second tab 12 in the winding direction. For the convenience of description, referring to FIG. 6A, the end region 14 of any one of the first tab 11 and the second tab 12 in the winding direction is taken as an example for illustration.

[0112] In FIG. 6A, for the tab corresponding to the end region 14, the upward arrow represents the outside of the tab, and the downward arrow represents the inside of the tab. Accordingly, the guard portion 20 has an inside guard layer 21 and an outside guard layer 22, which are respectively provided on both sides of the end region 14 in the thickness direction of the end region 14.

[0113] Here, “inside” and “outside” can be relative to the winding center of the winding structure 100, and inward and outward respectively refer to the direction close to the winding center and the direction away from the winding center, and the inside and the outside of a position / part respectively refer to the side adjacent to the winding center and the side away from the winding center of the position / part.

[0114] The protective portion 20 can protect the end region of the tab and other structures (e.g. the tab layers or separators on the inner and outer sides of the end region) on the inner and outer sides thereof, and the inner protective layer 21 and the outer protective layer 22 can separate the end region of the tab from other structures on the inner and outer sides thereof to reduce the possible adverse effects of the end region of the tab on the other structures on the inner and outer sides thereof, such as the risk of the burr of the cut edge of the end region of the tab piercing the separator of the adjacent layer to cause short circuit, thereby improving the reliability of the electrode assembly.

[0115] Referring to FIG. 6A, the inner protective layer 21 has a certain thickness, and thus the first side edge 211 of the inner protective layer 21 located inside the edge 141 of the end region 14 in the winding direction r (i.e. the first side edge 211 of the inner protective layer 21 located on the side away from the edge 141 of the end region 14) can form a step relative to the inner side surface of the tab where the inner protective layer 21 is located. Similarly, the outer protective layer 22 has a certain thickness, and thus the second side edge 221 of the outer protective layer 22 located inside the edge 141 of the end region 14 in the winding direction r (i.e. the second side edge 221 of the outer protective layer located on the side away from the edge 141 of the end region 14) can form a step relative to the outer side surface of the tab where the outer protective layer 22 is located. Here, the edge 141 is the intersection line of the end surface of the end corresponding to the end region 14 and the inner and outer side surfaces of the tab.

[0116] When the electrode assembly is cyclically expanded, the part of the tab where the inner protective layer 21 is provided and the part of the tab where the inner protective layer 21 is not provided are extruded by the inner tab layer or the separator, and the part of the tab where the inner protective layer 21 is provided is thicker than the part of the tab where the inner protective layer 21 is not provided, so that the part of the tab where the inner protective layer 21 is provided is more restricted than the part of the tab where the inner protective layer 21 is not provided when it expands outward, and such inconsistent expansion can form a shear stress at the step position; similarly, the part of the tab where the outer protective layer 22 is provided and the part of the tab where the outer protective layer 22 is not provided are extruded by the outer tab layer or the separator, and the part of the tab where the outer protective layer 22 is provided is thicker than the part of the tab where the outer protective layer 22 is not provided, so that the part of the tab where the outer protective layer 22 is provided is more restricted than the part of the tab where the outer protective layer 22 is not provided when it expands outward, and such inconsistent expansion can form a shear stress at the step position.

[0117] In the related art, when the first side edge 211 and the second side edge 221 are aligned in the winding direction r, the steps of the inner and outer side surfaces of the tab are also aligned accordingly, thereby forming a sudden change in thickness from the position without the protective layer to the position with the protective layer, and correspondingly a larger shear stress is superimposed at the aligned step position, thereby increasing the risk of cracks or even fractures of the tab.

[0118] In the embodiment, the first side edge 211 and the second side edge 221 are at least partially staggered with each other in the winding direction r, which can minimize or eliminate the superposition of the inner and outer steps of the inner and outer protective layers on the pole piece, so that the thickness gradually changes from the position without the protective layer to the position with the protective layer, thereby minimizing or eliminating the superposition of the shear stress formed on the pole piece when the electrode assembly is cyclically expanded at the step position, thereby reducing the risk of cracks or even breakage of the pole piece caused by excessive stress at the step position, and thus improving the reliability of the electrode assembly.

[0119] FIG. 6B is a schematic view of FIG. 6A from a top view. In FIG. 6B, the edge 141 of the end region 14 of the first pole piece 11 or the second pole piece 12 blocked by the protective portion is shown by a dashed line, and the first side edge 211 blocked by the protective portion and the pole piece is shown by a dot-dashed line. That is, the projection of the first side edge 211 and the second side edge 221 on the reference plane perpendicular to the thickness direction of the end region is at least partially staggered with each other in the winding direction r.

[0120] One implementation form of the first side edge 211 and the second side edge 221 being at least partially staggered with each other in the winding direction r can be seen from FIG. 6A and FIG. 6B. In other embodiments, the first side edge 211 and the second side edge 221 being at least partially staggered with each other in the winding direction r can also adopt other implementation forms.

[0121] The specific implementation form of the staggering can be selected according to actual needs, for example, selected according to the polarity, length, energy density, and buffering effect on the expansion pressure of the pole piece.

[0122] Referring to FIG. 6A and FIG. 6B, in some embodiments, the second side edge 221 is farther away from the edge 141 of the end region 14 than the first side edge 211 in the winding direction r.

[0123] As can be seen from FIG. 6B, in the winding direction r (corresponding to the length direction of the pole piece in the unfolded state), the minimum distance d1 between the first side edge 211 and the edge 141 is less than the minimum distance d2 between the second side edge 221 and the edge 141, so the second side edge 221 is farther away from the edge 141 of the end region 14 than the first side edge 211 in the winding direction r. In this way, this structure can form pole piece surfaces with different shielding ranges at the end region of the pole piece provided with the protective portion, in which the less shielded inner pole piece surface can obtain a relatively larger effective active area, which is conducive to improving the energy density of the electrode assembly, and the outer protective layer with a larger shielding range can more effectively disperse the extrusion pressure when the battery assembly is cyclically expanded, thereby reducing the risk of damage to the pole piece caused by the extrusion pressure.

[0124] FIG. 6C and FIG. 6D are schematic diagrams of another two protective portions arranged at the end region of the pole piece, respectively. FIG. 6C and FIG. 6D are embodiments of another two protective portions arranged at the end region of the pole piece in different manners with reference to FIG. 6B. In FIG. 6C, the edge 141 of the end region 14 of the first pole piece 11 or the second pole piece 12 blocked by the protective portion is shown by a dashed line, and the first side edge 211 blocked by the protective portion and the pole piece is shown by a dot-dashed line.

[0125] Referring to FIG. 6C, in some embodiments, the first side edge 211 is farther away from the edge 141 of the end region 14 in the winding direction r than the second side edge 221.

[0126] As can be seen from FIG. 6C, in the winding direction r (corresponding to the length direction of the pole piece in the unfolded state), the minimum distance d1 of the first side edge 211 to the edge 141 is greater than the minimum distance d2 of the second side edge 221 to the edge 141, so the first side edge 211 is farther away from the edge 141 of the end region 14 in the winding direction r than the second side edge 221. In this way, such a structure can form pole piece surfaces with different blocking ranges at the end region of the pole piece where the protective portion is arranged, in which the less blocked outer pole piece surface can obtain a relatively larger effective active area, which is conducive to improving the energy density of the electrode assembly, and the inner protective layer with a larger blocking range can more effectively disperse the extrusion force of the battery assembly during the cycle expansion, thereby reducing the risk of damage to the pole piece caused by the extrusion force.

[0127] In the above embodiments, the first side edge 211 and the second side edge 221 can be a straight line edge, a broken line edge, an arc line edge, or an edge composed of a combination of a broken line segment and an arc line segment, etc.

[0128] Referring to FIG. 6D, in some embodiments, the first side edge 211 includes a first sub-side edge 211a and a second sub-side edge 211b, the first sub-side edge 211a is farther away from the edge 141 of the end region 14 in the winding direction r than the second side edge 221, and the second sub-side edge 211b is closer to the edge 141 of the end region 14 in the winding direction r than the second side edge 221.

[0129] In FIG. 6D, the first side edge 211 can include different portions having different distances from the edge 141 of the end region 14, and can accordingly present a zigzag shape, and the second side edge 221 can be a straight line or other shape. The first side edge 211 and the second side edge 221 can intersect, such that a first sub-side edge is farther from the edge 141 than a corresponding portion of the second side edge 221, and a second sub-side edge is closer to the edge 141 than a corresponding portion of the second side edge 221. Such a structure can more flexibly adjust the degree of shielding of the inner and outer side surfaces of the pole piece, thereby reducing shear stress while also satisfying the requirements of dispersing extrusion pressure, improving the energy density of the battery assembly, and the like. In addition, such a structure also allows the inner and outer protective layers to have substantially the same coverage range on the inner and outer sides of the pole piece, thereby making the bonding strength of the inner and outer protective layers to the inner and outer side surfaces of the pole piece close, and reducing the risk of unilateral detachment of the protective layer due to a large difference in bonding strength.

[0130] Referring to FIGS. 5 and 6A, in some embodiments, at least one of the inner protective layer 21 and the outer protective layer 22 covers at least part of the edge 141 of the end region 14.

[0131] The protective portion can cover part or all of the edge 141 by the inner protective layer 21 or the outer protective layer 22, or jointly cover part or all of the edge 141 by the inner protective layer 21 and the outer protective layer 22. In this way, the burrs of the end region of the pole piece due to cutting and the like can be isolated from the separator by the protective portion, thereby reducing the risk of the burrs piercing the separator and causing short circuit between the pole pieces of different polarities.

[0132] Referring to FIG. 6B, in some embodiments, the inner protective layer 21 and the outer protective layer 22 both extend beyond the end region 14 in the width direction of the end region 14, which is perpendicular to the winding direction r.

[0133] By extending the inner protective layer 21 and the outer protective layer 22 beyond the end region 14 in the width direction of the end region 14, the edge 141 can be entirely covered, so that the burrs of the edge 141 can be isolated from the separator, thereby more greatly reducing the risk of the burrs piercing the separator and causing short circuit between the pole pieces of different polarities.

[0134] The protective portion 20 at the end region 14 of the first pole piece 11 or the second pole piece 12 can adopt various forms of arrangement. For example, the protective portion 20 can be formed by pasting a tape on the surface of the pole piece, or by coating a protective coating on the surface of the pole piece, and the like.

[0135] Fig. 6E is an exploded schematic view of Fig. 6A. Referring to Figs. 6A and 6E, in some embodiments, the inner protective layer 21 is bonded to the inner side surface of the end region 14 in the thickness direction of the end region 14, and the outer protective layer 22 is bonded to the outer side surface of the end region 14 in the thickness direction of the end region 14.

[0136] The inner side surface of the end region 14 in the thickness direction of the end region 14 is the inner side surface of the pole piece at the end region 14, and the inner protective layer 21 is fixed on the surface by bonding to form a covering effect on the surface. The outer side surface of the end region 14 in the thickness direction of the end region 14 is the outer side surface of the pole piece at the end region, and the outer protective layer 22 is fixed on the surface by bonding to form a covering effect on the surface.

[0137] The inner protective layer 21 and the outer protective layer 22 are respectively bonded to the inner and outer side surfaces of the end region 14 by bonding, which can form a stable and reliable bonding effect with the pole piece, reduce the risk of falling off, and also facilitate the assembly relative to the pole piece.

[0138] Referring to Fig. 6E, in some embodiments, the protective portion 20 includes two single-sided adhesive tapes respectively forming the inner protective layer 21 and the outer protective layer 22, and the two single-sided adhesive tapes are bonded to each other by the adhesive layers of the portions protruding from the edge 141 of the end region 14.

[0139] The single-sided adhesive tape can include an adhesive tape substrate and an adhesive layer provided on one side surface of the adhesive tape substrate, and the surface of the adhesive tape substrate away from the adhesive layer is a non-bonding surface. The material of the adhesive tape substrate can include polypropylene (PP), polyethylene terephthalate (PET), or polyimide (PI), etc. The material of the adhesive layer can include acrylic glue (PMMA glue), etc.

[0140] In Fig. 6E, the inner protective adhesive layer 21g is the adhesive layer of the single-sided adhesive tape forming the inner protective layer 21, and the outer protective adhesive layer 22g is the adhesive layer of the single-sided adhesive tape forming the outer protective layer 22. Referring to Fig. 6A, the reference plane rp shown by the double-dot chain line passes through the edge 141 of the end region 14. The portions of the two single-sided adhesive tapes protruding from the edge 141 of the end region 14 are the extension section 23 on the left side of the reference plane rp in Fig. 6A, and the first extension section adhesive layer 231g attached to the first extension section adhesive tape substrate 231 and the second extension section adhesive layer 232g attached to the second extension section adhesive tape substrate 232 of the two single-sided adhesive tapes corresponding to the extension section 23 are bonded to each other, which can form a sealing effect on the edge 141 to reduce or eliminate the risk of burr exposure.

[0141] The two single-sided tapes are respectively used to form the inner protective layer 21 and the outer protective layer 22 of the protective portion 20, which can simplify the setting of the protective portion 20 on the end portion area 14 of the first pole piece 11 or the second pole piece 12. In addition, the single-sided tapes are easy to obtain and have shapes and sizes that are easy to meet design requirements, thereby facilitating the reduction of the difficulty in manufacturing the electrode assembly and the improvement of the processing efficiency of the electrode assembly. Moreover, the mutual adhesion of the adhesive layers of the two single-sided tapes that protrude from the portions of the edge 141 of the end portion area 14 can make the protective portion 20 and the end portion area 14 form a more closely combined force, thereby reducing the risk of falling off.

[0142] FIG. 7A is a schematic view of another protective portion set on the end portion area of a pole piece. FIG. 7B is an exploded schematic view of FIG. 7A. Referring to FIGS. 7A and 7B, in some embodiments, the protective portion 20 includes a single-sided tape that is folded to form the inner protective layer 21 and the outer protective layer 22, and the opposite portions of the adhesive layers of the single-sided tape that protrude from the edge 141 of the end portion area 14 are mutually adhered.

[0143] Compared with the two single-sided tapes shown in FIG. 6E, the inner protective layer 21 and the outer protective layer 22 in FIGS. 7A and 7B are realized by a single single-sided tape. The single-sided tape can form two opposite adhesive layers by folding. In FIG. 7B, the inner protective adhesive layer 21g and the outer protective adhesive layer 22g are respectively the adhesive layer segments for forming the inner protective layer 21 and the outer protective layer 22 in the folded single-sided tape.

[0144] Referring to FIG. 7A, the reference plane rp shown by the double-dot chain line passes through the edge 141 of the end portion area 14. The portion of the single-sided tape that protrudes from the edge 141 of the end portion area 14 is the extension segment 23 on the left side of the reference plane rp in FIG. 7A. The opposite portions of the extension segment adhesive layer attached to the extension segment tape base of the single-sided tape corresponding to the extension segment 23 are mutually adhered. The structure formed by folding and adhering has a closing effect on the edge 141, thereby reducing or eliminating the risk of burr exposure.

[0145] The two single-sided tapes are respectively used to form the inner protective layer 21 and the outer protective layer 22 of the protective portion 20, which can simplify the setting of the protective portion 20 on the end portion area 14 of the first pole piece 11 or the second pole piece 12. In addition, the single-sided tapes are easy to obtain and have shapes and sizes that are easy to meet design requirements, thereby facilitating the reduction of the difficulty in manufacturing the electrode assembly and the improvement of the processing efficiency of the electrode assembly. Moreover, the mutual adhesion of the adhesive layers of the two single-sided tapes that protrude from the portions of the edge 141 of the end portion area 14 can make the protective portion 20 and the end portion area 14 form a more closely combined force, thereby reducing the risk of falling off.

[0146] Referring to FIG. 6A and FIG. 7A, in some embodiments, the protective portion 20 includes an extension section 23 which is located outside the edge 141 of the end region 14 in the winding direction r (i.e. protrudes relative to the edge 141 of the end region 14 in the winding direction r or the opposite direction of the winding direction r) and is connected with at least one of the inner protective layer 21 and the outer protective layer 22.

[0147] Referring to the foregoing embodiments in which the protective portion is implemented by a single-sided tape, the extension section 23 can be a portion of the single-sided tape which is located outside the pole piece in the winding direction r. In other embodiments, the inner protective layer 21 and the outer protective layer 22 can also be independent of each other without being bonded to each other. The extension section 23 can be integrally formed with the inner protective layer 21 and / or the outer protective layer 22, or can be independently formed and then connected.

[0148] By providing the extension section 23, the covering and isolating effect of at least one of the inner protective layer 21 and the outer protective layer 22 on the edge 141 is facilitated, and the risk that the inner protective layer 21 and the outer protective layer 22 move relative to the surface of the pole piece and lose the covering and isolating effect on the edge 141 is reduced. In addition, the extension section 23 can also support the isolating member to a certain extent.

[0149] For the electrode assembly, in different embodiments, the number, structural form or arrangement position of the protective portion can be different. For example, in FIG. 4 and FIG. 5, the protective portion 20 can be arranged at the end region 14 on both sides of the first pole piece 11 and the second pole piece 12 in the winding direction r. In other embodiments, the protective portion 20 can also be arranged only at the end region of one of the first pole piece 11 and the second pole piece 12 on both sides or one side in the winding direction r, or at the end region of the first pole piece 11 and the second pole piece 12 on the same side or different sides in the winding direction r.

[0150] FIG. 8A, FIG. 9A, FIG. 10A, FIG. 11A, FIG. 12A, FIG. 13A, FIG. 14A and FIG. 15A are respectively cross-sectional schematic views of the winding structure of an electrode assembly according to other embodiments of the battery cell of the present disclosure. FIG. 8B, FIG. 9B, FIG. 10B, FIG. 11B, FIG. 12B, FIG. 13B, FIG. 14B and FIG. 15B are respectively schematic views of the first pole piece and the second pole piece in an unfolded state in the embodiments shown in FIG. 8A, FIG. 9A, FIG. 10A, FIG. 11A, FIG. 12A, FIG. 13A, FIG. 14A and FIG. 15A.

[0151] In FIGS. 8A and 8B, the leading end 11a and the trailing end 11b of the first pole piece 11 and the leading end 12a and the trailing end 12b of the second pole piece 12 are each provided with a guard portion 20, wherein the first leading end guard portion 20a' provided at the leading end 11a of the first pole piece 11 has a longer extension which extends inwardly to a position substantially flush with the separators 131 and 132 and is wound for not less than one winding number. The first trailing end guard portion 20c provided at the trailing end 11b of the first pole piece 11 and the second leading end guard portion 20b and the second trailing end guard portion 20d provided at the leading end 12a and the trailing end 12b of the second pole piece 12, respectively, have shorter extensions which are each wound for less than one winding number.

[0152] In FIGS. 9A and 9B, the leading end 11a and the trailing end 11b of the first pole piece 11 are provided with a guard portion 20, while the leading end 12a and the trailing end 12b of the second pole piece 12 are not provided with a guard portion 20, wherein the first leading end guard portion 20a and the first trailing end guard portion 20c provided at the leading end 11a and the trailing end 11b of the first pole piece 11, respectively, have shorter extensions which are each wound for less than one winding number.

[0153] In FIGS. 10A and 10B, the leading end 11a and the trailing end 11b of the first pole piece 11 are provided with a guard portion 20, while the leading end 12a and the trailing end 12b of the second pole piece 12 are not provided with a guard portion 20, wherein the first leading end guard portion 20a' provided at the leading end 11a of the first pole piece 11 has a longer extension which extends inwardly to a position substantially flush with the separators 131 and 132 and is wound for not less than one winding number. The first trailing end guard portion 20c provided at the trailing end 11b of the first pole piece 11 has a shorter extension which is wound for less than one winding number.

[0154] In FIGS. 11A and 11B, the leading end 11a and the trailing end 11b of the first pole piece 11 are not provided with a guard portion 20, while the leading end 12a and the trailing end 12b of the second pole piece 12 are provided with a guard portion 20, wherein the second leading end guard portion 20b and the second trailing end guard portion 20d provided at the leading end 12a and the trailing end 12b of the second pole piece 12, respectively, have shorter extensions which are each wound for less than one winding number.

[0155] In FIGS. 12A and 12B, the leading end 11a and the trailing end 11b of the first pole piece 11 are not provided with a guard portion 20, while the leading end 12a and the trailing end 12b of the second pole piece 12 are provided with a guard portion 20, wherein the second leading end guard portion 20b' provided at the leading end 12a of the second pole piece 12 has a longer extension which extends inwardly and is wound for not less than one winding number. The extension does not extend to a position substantially flush with the separators 131 and 132. The second trailing end guard portion 20d provided at the trailing end 12b of the second pole piece 12 has a shorter extension which is wound for less than one winding number.

[0156] In FIGS. 13A and 13B, neither the leading end 11a of the first tab 11 nor the leading end 12a of the second tab 12 is provided with the guard 20, and both the trailing end 11b of the first tab 11 and the trailing end 12b of the second tab 12 are provided with the guard 20, wherein the first trailing end guard 20c provided at the trailing end 11b of the first tab 11 and the second trailing end guard 20d provided at the trailing end 12b of the second tab 12 have a short extension, which is wound less than one turn.

[0157] In FIGS. 14A and 14B, neither the leading end 11a of the first tab 11, the leading end 12a of the second tab 12, nor the trailing end 12b of the second tab 12 is provided with the guard 20, and the trailing end 11b of the first tab 11 is provided with the guard 20, wherein the first trailing end guard 20c provided at the trailing end 11b of the first tab 11 has a short extension, which is wound less than one turn.

[0158] In FIGS. 15A and 15B, neither the leading end 11a of the first tab 11, the trailing end 11b of the first tab 11, nor the leading end 12a of the second tab 12 is provided with the guard 20, and the trailing end 12b of the second tab 12 is provided with the guard 20, wherein the second trailing end guard 20d provided at the trailing end 12b of the second tab 12 has a short extension, which is wound less than one turn.

[0159] In the above embodiments, the first tab 11 can be a negative tab, and the second tab 12 can be a positive tab, and the length of the first tab 11 is greater than the length of the second tab 12. In other embodiments, the first tab 11 can be a positive tab, and the second tab 12 can be a negative tab. In other embodiments, the lengths of the first tab 11 and the second tab 12 can be the same or different.

[0160] Referring to FIGS. 8A, 8B, 10A, 10B, 12A and 12B, in some embodiments, the guard 20 is provided at the leading end 11a, 12a of at least one of the first tab 11 and the second tab 12 in the winding direction r, and the extension 23 is wound N1 turns, wherein N1≥1.

[0161] FIGS. 8A and 10A show a cross-sectional structure of a first leading end guard 20a’ provided at the leading end 11a of the first tab 11 in the winding direction r. Such a first leading end guard 20a’ has a long extension 23, which is wound N1 turns on the inside, and N1≥1. FIG. 12A shows a cross-sectional structure of a second leading end guard 20b’ provided at the leading end 12a of the second tab 12 in the winding direction r. Such a second leading end guard 20b’ has a long extension 23, which is wound N1 turns on the inside, and N1≥1.

[0162] Here, N1 is not limited to a positive integer, but is a positive real number greater than or equal to 1. It can be seen in FIG. 8A and FIG. 10A that the extension section 23 can extend to a position flush with the starting end of the spacer, or it can be seen in FIG. 12A that the extension section 23 does not extend to a position flush with the starting end of the spacer.

[0163] The extension section 23 of the guard portion 20 provided at the starting end of at least one of the first pole piece 11 and the second pole piece 12 in the winding direction r is provided to be wound for a length of not less than 1 turn, which can effectively enhance the inner turn support strength of the wound structure 100, thereby reducing the risk of collapse of the inner turns.

[0164] Referring to FIG. 4, FIG. 5, FIG. 9A, FIG. 9B, FIG. 11A, and FIG. 11B, in some embodiments, the guard portion 20 is provided at the starting end 11a, 12a of at least one of the first pole piece 11 and the second pole piece 12 in the winding direction r, and the extension section 23 is wound for N1 turns, where 0 < N1 < 1.

[0165] In FIG. 4, FIG. 9A, and FIG. 11A, the extension section 23 of the first starting end guard portion 20a provided at the starting end 11a or the second starting end guard portion 20b provided at the starting end 12a is shorter than in the embodiments corresponding to FIG. 8A, FIG. 10A, and FIG. 12A, respectively. Here, N1 is a positive real number greater than 0 and less than 1.

[0166] The extension section 23 of the guard portion 20 provided at the starting end of at least one of the first pole piece 11 and the second pole piece 12 in the winding direction r is provided to be wound for a length of less than 1 turn with the spacer, which is advantageous for saving the material usage of the guard portion.

[0167] Referring to FIG. 8A and FIG. 10A, in some embodiments, the portion of the spacer 131, 132 located outside the edge of the starting end 11a in the winding direction r is wound for N1 turns.

[0168] By winding the portion of the spacer located outside the edge of the starting end for N1 turns, the spacer and the extension section of the guard portion are collectively wound for N1 turns outside the edge of the starting end, thereby achieving the support effect of the extension section on the spacer of the inner turns of the wound structure, enhancing the inner turn support strength of the wound structure, and thereby reducing the risk of collapse of the inner turns.

[0169] Referring to FIG. 4, FIG. 9A, FIG. 11A, and FIG. 12A, in some embodiments, the portion of the spacer 131, 132 located outside the edge of the starting end 11a (or 12a) in the winding direction r is wound for N2 turns, where N2 > N1.

[0170] Here, N2 is a positive real number greater than N1. By winding the portion of the spacer outside the end edge in N2 turns, in addition to the N1 turns wound by the extension section of the guard portion, the winding difficulty can be reduced, and the manufacturing process can be simplified.

[0171] Referring to FIGS. 4, 5, and 8A to 15B, in some embodiments, the guard portion 20 is provided at the end 11b, 12b of at least one of the first and second electrode tabs 11, 12 in the winding direction r, and the extension section 23 is wound in N3 turns, where 0 < N3 < 1.

[0172] In FIGS. 4, 9A, 10A, 11A, 12A, 13A, 14A, and 15A, the extension section 23 of the first end guard portion 20c provided at the end 11b or the second end guard portion 20d provided at the end 12b is wound in N3 turns on the outside, and is short in length. Here, N3 is a positive real number greater than 0 and less than 1.

[0173] The extension section 23 of the guard portion 20 provided at the end of at least one of the first and second electrode tabs 11, 12 in the winding direction r is provided to be wound in a length of less than 1 turn, which is advantageous in saving the use of guard portion material. In addition, the shorter extension section 23 located on the outside can reduce the volume of the electrode assembly, which is advantageous in improving the energy density of the electrode assembly.

[0174] In one aspect of the present disclosure, a battery 40 including the battery cell 30 of any of the preceding embodiments is provided. The battery employing the battery cell described above can achieve more optimal use reliability.

[0175] In one aspect of the present disclosure, a power consuming device including the battery 40 of any of the preceding embodiments is provided. The power consuming device employing the battery described above can achieve more optimal use reliability.

[0176] In some specific embodiments, as shown in FIGS. 3-6B and 6E, the battery cell 30 includes an electrode assembly 10, a housing 31, and an end cap 32. The housing 31 has a receiving cavity 31c configured to receive the electrode assembly 10 and an open end 31o in communication with the receiving cavity 31c. The end cap 32 covers the open end 31o. The electrode assembly 10 includes a first electrode tab 11, a second electrode tab 12, and spacers 131, 132 provided between the first and second electrode tabs 11, 12. The first and second electrode tabs 11, 12 and the spacers 131, 132 are wound in a winding direction r and form a wound structure 100. The first electrode tab 11 is a negative electrode tab, the second electrode tab 12 is a positive electrode tab, and the first electrode tab 11 is longer than the second electrode tab 12.

[0177] The first pole piece 11 and the second pole piece 12 are each provided with a protective portion 20 at both side end region 14 in the winding direction r, the protective portion 20 has an inner protective layer 21 and an outer protective layer 22, the inner protective layer 21 and the outer protective layer 22 are respectively arranged at both sides of the end region 14 in the thickness direction of the end region 14, the inner protective layer 21 has a first side edge 211, the outer protective layer 22 has a second side edge 221, the first side edge 211 and the second side edge 221 are staggered with each other in the winding direction r. The inner protective layer 21 and the outer protective layer 22 each cover the whole of the edge 141 of the end region 14, and the protective portion 20 further comprises an extension section 23, the extension section 23 is located outside the edge 141 of the end region 14 along the winding direction r, and is connected with at least one of the inner protective layer 21 and the outer protective layer 22.

[0178] The protective portion 20 comprises two single-sided adhesive tapes respectively forming the inner protective layer 21 and the outer protective layer 22, the inner protective layer 21 is bonded with the inner side surface of the end region 14 in the thickness direction of the end region 14, and the outer protective layer 22 is bonded with the outer side surface of the end region 14 in the thickness direction of the end region 14. The two single-sided adhesive tapes are bonded with each other from the adhesive layers of the portions of the edge 141 of the end region 14.

[0179] So far, the embodiments of the present disclosure have been described in detail. In order to avoid obscuring the concept of the present disclosure, some details known in the art are not described. Those skilled in the art can fully understand how to implement the technical solutions disclosed herein according to the above description.

[0180] Although some specific embodiments of the present disclosure have been described in detail through examples, those skilled in the art should understand that the above examples are only for illustration, not for limiting the scope of the present disclosure. Those skilled in the art should understand that the above embodiments can be modified or some technical features can be replaced equivalently without departing from the scope and spirit of the present disclosure. The scope of the present disclosure is defined by the appended claims.

Claims

1. A battery cell (30) comprising: an electrode assembly (10) ; a case (31) having an accommodation cavity (31c) configured to accommodate the electrode assembly (10) and an open end (31o) communicating with the accommodation cavity (31c) ; and an end cover (32) covering the open end (31o) ; wherein the electrode assembly (10) comprises a first electrode tab (11), a second electrode tab (12) and a separator (131, 132) disposed between the first electrode tab (11) and the second electrode tab (12), the first electrode tab (11), the second electrode tab (12) and the separator (131, 132) are wound along a winding direction (r) and form a wound structure (100), at least one of the first electrode tab (11) and the second electrode tab (12) is provided with a protection portion (20) at an end region (14) on at least one side in the winding direction (r), the protection portion (20) has an inner protection layer (21) and an outer protection layer (22), the inner protection layer (21) and the outer protection layer (22) are respectively disposed on both sides of the end region (14) in a thickness direction of the end region (14), along the winding direction (r), the inner protection layer (21) has a first side edge (211) located inside an edge (141) of the end region (14), the outer protection layer (22) has a second side edge (221) located inside the edge (141) of the end region (14), the first side edge (211) and the second side edge (221) are at least partially staggered with each other in the winding direction (r). The first side edge (211) is farther away from the edge (141) of the end region (14) than the second side edge (221) in the winding direction (r).

2. The battery cell (30) of claim 1, wherein, The first side edge (211) comprises a first sub-side edge (211a) and a second sub-side edge (211b), the first sub-side edge (211a) is farther away from the edge (141) of the end region (14) than the second side edge (221) in the winding direction (r), the second sub-side edge (211b) is closer to the edge (141) of the end region (14) than the second side edge (221) in the winding direction (r).

3. The battery cell (30) of claim 1, wherein, At least one of the inner protection layer (21) and the outer protection layer (22) covers at least part of the edge (141) of the end region (14).

4. The battery cell (30) according to any one of claims 1-3, wherein, Both the inner protection layer (21) and the outer protection layer (22) exceed the end region (14) in a width direction of the end region (14), the width direction of the end region (14) is perpendicular to the winding direction (r).

5. The battery cell (30) of claim 4, wherein, The protection portion (20) comprises an extension section (23), the extension section (23) is located outside the edge (141) of the end region (14) in the winding direction (r) and is connected with at least one of the inner protection layer (21) and the outer protection layer (22).

6. The battery cell (30) according to claim 4 or 5, wherein ​ 7. The battery cell (30) of claim 6, wherein, The protective portion (20) is provided at a start end (11a, 12a) of at least one of the first and second pole pieces (11, 12) in the winding direction (r), and the extension section (23) is wound N1 turns, where N1 ≥ 1.

8. The battery cell (30) of claim 6, wherein, The protective portion (20) is provided at a start end (11a, 12a) of at least one of the first and second pole pieces (11, 12) in the winding direction (r), and the extension section (23) is wound N1 turns, where 0 < N1 < 1.

9. The battery cell (30) according to claim 7 or 8, wherein The spacer (131, 132) is wound N1 turns at a portion thereof that is outside an edge of the start end (11a, 12a) in the winding direction (r).

10. The battery cell (30) according to claim 7 or 8, wherein The spacer (131, 132) is wound N2 turns at a portion thereof that is outside an edge of the start end (11a, 12a) in the winding direction (r), where N2 > N1.

11. The battery cell (30) according to any one of claims 6-10, wherein, The protective portion (20) is provided at an end (11b, 12b) of at least one of the first and second pole pieces (11, 12) in the winding direction (r), and the extension section (23) is wound N3 turns, where 0 < N3 < 1.

12. The battery cell (30) according to any one of claims 1-11, wherein, The inner protective layer (21) is bonded to an inner surface of the end portion region (14) in a thickness direction thereof, and the outer protective layer (22) is bonded to an outer surface of the end portion region (14) in the thickness direction thereof.

13. The battery cell (30) of claim 12, wherein, The protective portion (20) includes two single-sided adhesive tapes that form the inner and outer protective layers (21, 22), respectively, and the two single-sided adhesive tapes are bonded to each other at portions of adhesive layers thereof that protrude from edges (141) of the end portion region (14).

14. The battery cell (30) of claim 12, wherein, The protective portion (20) includes a single-sided adhesive tape that forms the inner and outer protective layers (21, 22) by being folded, and the single-sided adhesive tape is bonded to itself at a portion of an adhesive layer thereof that protrudes from an edge (141) of the end portion region (14).

15. A battery (40) comprising the battery cell (30) according to any one of claims 1 to 14.

16. An electric device comprising the battery (40) according to claim 15.

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