Battery monomer, battery and electric device

Abstract

A battery cell, a battery, and an electric device are provided. The battery cell (30) includes: an electrode assembly (10); a housing (31); the end cover (32) covers the opening end (31o) of the shell (31); wherein the electrode assembly (10) comprises a first pole piece (11), a second pole piece (12) and separators (131, 132) arranged between the first pole piece (11) and the second pole piece (12), and is wound along a winding direction (r) to form a winding structure (100); at least one of the first pole piece (11) and the second pole piece (12) is provided with a protective part (20) in an end region (14) on at least one side in the winding direction (r), the protective part (20) is provided with an inner protective layer (21) and an outer protective layer (22), and the inner protective layer (21) and the outer protective layer (22) are provided with a first side edge (211) and a second side edge (221) in the winding direction. The first side (211) and the second side (221) are at least partially offset from each other in the winding direction (r).

Description

Technical Field

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

[0002] Secondary batteries, especially lithium-ion batteries, offer advantages such as high voltage, high specific energy, long cycle life, environmental friendliness, a wide operating temperature range, and low self-discharge. They are widely used in portable electronic devices and powering large electric vehicles, playing a significant role in addressing environmental pollution and the energy crisis. With the widespread use of secondary batteries, battery reliability has become a matter of close concern to users. Utility Model Content

[0003] In one aspect of the present disclosure, a battery cell is provided, comprising: an electrode assembly; a shell having a accommodating cavity and an open end connected to the accommodating cavity, the accommodating cavity being configured to accommodate the electrode assembly; and an end cover covering the open end; wherein the electrode assembly comprises: a first pole sheet, a second pole sheet and an isolating member arranged between the first pole sheet and the second pole sheet, the first pole sheet, the second pole sheet and the isolating member being wound along a winding direction and forming a winding structure; wherein at least one of the first pole sheet and the second pole sheet is provided with a protective portion in an end region on 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 arranged on both sides of the end region in the thickness direction of the end region, along the winding direction, the inner protective layer has a first side located inside the edge of the end region, the outer protective layer has a second side located inside the edge of the end region, and the first side and the second side are at least partially staggered with each other in the winding direction.

[0004] A protective portion is provided in the end region of the pole piece, and the protective portion can be used to achieve protective effects such as dispersing and buffering the shear stress of the inner and outer layers of the pole piece adjacent to the end region of the pole piece. By making the first side edge of the inner protective layer and the second side edge of the outer protective layer of the protective portion at least partially staggered with each other in the winding direction, the superposition of the inner and outer steps of the inner and outer protective layers on the pole piece can be minimized or eliminated, and accordingly, the superposition of the shear stress on the pole piece formed when the electrode assembly cyclically expands at the step position can be minimized or eliminated, thereby reducing the risk of cracking or even breaking the pole piece due to excessive stress at the step position, which is beneficial to improving the reliability of the battery cell.

[0005] In some embodiments, the first side is further away from the edge of the end region than the second side in the rolling direction.

[0006] The first side is further away from the edge of the end region than the second side in the winding direction, which is equivalent to the minimum distance between the first side and the edge being greater than the minimum distance between the second side and the edge in the winding direction (corresponding to the length direction of the electrode sheet in the unfolded state). This structure can form electrode sheet surfaces with different shielding ranges in the end region of the electrode sheet where the protective portion is provided. The less shielded outer surface of the electrode sheet can obtain a relatively larger effective active area, which is beneficial to improving the energy density of the electrode assembly. The inner protective layer with a larger shielding range can more effectively disperse the extrusion force during the cyclic expansion of the battery assembly, thereby reducing the risk of damage to the electrode sheet caused by the extrusion force.

[0007] In some embodiments, the first side includes a first sub-side and a second sub-side, wherein the first sub-side is farther away from the edge of the end area than the second side in the winding direction, and the second sub-side is closer to the edge of the end area than the second side in the winding direction.

[0008] The first sub-side of the first side is farther away from the edge than the corresponding part of the second side, and the second sub-side is closer to the edge than the corresponding part of the second side, which is equivalent to the first side and the second side being able to cross. This structure can more flexibly adjust the degree of obstruction of the inner and outer surfaces of the electrode, thereby reducing shear stress while also meeting the requirements of dispersing extrusion force, improving the energy density of battery components, etc. In addition, this structure also allows the inner and outer protective layers to have basically the same coverage on the inside and outside of the electrode, so that the bonding strength of the inner and outer protective layers to the inner and outer surfaces of the electrode is close, reducing the risk of easy detachment of the single-sided protective layer due to a large difference in bonding strength.

[0009] In some embodiments, at least one of the inner armor layer and the outer armor layer covers at least a portion of an edge of the end region.

[0010] The protective part can cover part or all of the edge through the inner protective layer or the outer protective layer, or can cover part or all of the edge through the inner protective layer and the outer protective layer. In this way, the protective part can be used to isolate the burrs in the end area of ​​the pole piece due to cutting and other reasons from the isolating member, thereby reducing the risk of the burrs at this position piercing the isolating member and causing a short circuit between pole pieces of different polarities.

[0011] In some embodiments, both the inner protective layer and the outer protective layer extend beyond the end region in a width direction of the end region, and the width direction of the end region is perpendicular to the winding direction.

[0012] By making the inner protective layer and the outer protective layer extend beyond the end area in the width direction of the end area, an overall wrapping of the edge can be formed, so that the burrs on the edge can be isolated from the insulating member, thereby greatly reducing the risk of the burrs at this position piercing the insulating member and causing a short circuit between pole pieces of different polarities.

[0013] In some embodiments, the protective portion includes an extension segment, which is located outside the edge of the end region along the winding direction and is connected to at least one of the inner protective layer and the outer protective layer.

[0014] The provision of the extension section facilitates the edge coverage and isolation of at least one of the inner and outer protective layers, reducing the risk of the inner and outer protective layers shifting relative to the electrode surface and losing their edge coverage and isolation. Furthermore, the extension section can provide support for the isolation member to a certain extent.

[0015] In some embodiments, the protective portion is provided at a starting end of at least one of the first pole piece and the second pole piece in the winding direction, and the extension section is wound into N1 turns, where N1≥1.

[0016] The extension section of the protective portion provided at the starting 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 into a length of not less than one circle, which can effectively enhance the inner ring support strength of the winding structure, thereby reducing the risk of inner ring collapse.

[0017] In some embodiments, the protective portion is provided at the starting end of at least one of the first pole piece and the second pole piece in the winding direction, and the extension section is wound into N1 turns, wherein 0 <N1<1。

[0018] The extension section of the protective portion provided at the starting 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 with the isolation member to form a length less than one circle, which is beneficial to saving material usage of the protective portion.

[0019] In some embodiments, the portion of the isolating member located outside the edge of the starting end along the winding direction is wound into N1 turns.

[0020] By winding the part of the isolator located outside the starting edge into N1 turns, the isolator and the extension section of the protective part are jointly wound N1 turns outside the starting edge, so that the extension section can support the inner ring isolator of the winding structure, enhance the inner ring support strength of the winding structure, and thus reduce the risk of inner ring collapse.

[0021] In some embodiments, the portion of the isolating member located outside the edge of the starting end along the winding direction is wound into N2 turns, where N2>N1.

[0022] By winding the portion of the isolating member located outside the starting edge into N2 turns, which exceeds the N1 turns wound by the extended section of the protective portion, the winding difficulty can be reduced and the manufacturing process can be simplified.

[0023] In some embodiments, the protective portion 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 section is wound into N3 turns, wherein 0 <N3<1。

[0024] The extended section of the guard portion provided at the end of at least one of the first and second pole pieces in the winding direction r is configured to be wound to a length less than one turn, thereby conserving material for the guard portion. Furthermore, the shorter extended section located at the outer turn can reduce the volume of the electrode assembly, thereby facilitating an increase in the energy density of the electrode assembly.

[0025] In some embodiments, the inner protective layer is bonded to the inner surface of the end region in the thickness direction of the end region, and the outer protective layer is bonded to the outer surface of the end region in the thickness direction of the end region.

[0026] The inner protective layer and the outer protective layer are bonded to the inner and outer surfaces of the end area respectively, which can form a stable and reliable bond with the pole piece, reduce the risk of falling off, and are more convenient in assembly relative to the pole piece.

[0027] In some embodiments, the protective portion includes two single-sided tapes forming the inner protective layer and the outer protective layer respectively, and adhesive layers of portions of the two single-sided tapes protruding from edges of the end regions are bonded to each other.

[0028] Using two single-sided tapes to form the inner and outer protective layers of the protective portion, respectively, simplifies the placement of the protective portion in the end regions of the first or second electrode piece. Single-sided tapes are easily available, and their shape and size easily meet design requirements, thereby reducing the difficulty of electrode assembly production and improving processing efficiency. Furthermore, the adhesive layers of the two single-sided tapes, which extend beyond the edges of the end regions, adhere to each other, creating a tighter bond between the protective portion and the end regions, reducing the risk of detachment.

[0029] In some embodiments, the protective portion includes a single-sided tape formed by folding the inner protective layer and the outer protective layer, and opposite portions of the adhesive layer of the single-sided tape protruding from edges of the end region are bonded to each other.

[0030] Using a single, folded piece of single-sided tape to form the inner and outer protective layers of the protective portion simplifies the placement of the protective portion in the end region of the first or second electrode piece. Furthermore, the single-sided tape is readily available, and its shape and size easily meet design requirements, thereby reducing the difficulty of electrode assembly production and improving processing efficiency. Furthermore, the adhesive layers of the single-sided tape protruding from the edges of the end regions adhere to each other, creating a tighter bond between the protective portion and the end region, reducing the risk of detachment.

[0031] In one aspect of the present disclosure, a battery is provided, comprising the aforementioned battery cell.

[0032] The battery using the aforementioned battery cell embodiment can achieve better reliability in use.

[0033] In one aspect of the present disclosure, an electric device is provided, comprising the aforementioned battery.

[0034] The electrical device using the aforementioned battery embodiment can achieve better reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the technical solutions of the embodiments of the present disclosure, the following briefly introduces the drawings required for use in the embodiments of the present disclosure. Obviously, the drawings described below are only some embodiments of the present disclosure. For ordinary technicians in this field, other drawings can be obtained based on the drawings without any creative work.

[0036] The present disclosure can be more clearly understood from the following detailed description with reference to the accompanying drawings, in which:

[0037] Figure 1 is a schematic structural diagram of some embodiments of the electric device according to the present disclosure;

[0038] Figure 2 is an exploded schematic diagram of some embodiments of the battery according to the present disclosure;

[0039] Figure 3 is an exploded schematic diagram of some embodiments of a battery cell according to the present disclosure;

[0040] Figure 4 is a cross-sectional schematic diagram of a winding structure of an electrode assembly according to an embodiment of a battery cell of the present disclosure;

[0041] Figure 5 yes Figure 4 A schematic diagram of the first pole piece and the second pole piece in the embodiment shown in the unfolded state;

[0042] Figure 6Ais a schematic diagram of a protective portion disposed in an end region of a pole piece according to some embodiments of a battery cell disclosed herein;

[0043] Figure 6B yes Figure 6A Schematic diagram from a top-down perspective;

[0044] Figure 6C and Figure 6D They are schematic diagrams of the arrangement of the other two types of protective parts in the end area of ​​the pole piece;

[0045] Figure 6E yes Figure 6A Schematic diagram of the decomposition;

[0046] Figure 7A is a schematic diagram showing another embodiment of a protective portion disposed in the end region of a pole piece;

[0047] Figure 7B yes Figure 7A Schematic diagram of the decomposition;

[0048] Figure 8A 、 Figure 9A 、 Figure 10A 、 Figure 11A 、 Figure 12A 、 Figure 13A 、 Figure 14A and Figure 15A are schematic cross-sectional views of winding structures of electrode assemblies according to other embodiments of the battery cell disclosed herein;

[0049] Figure 8B 、 Figure 9B 、 Figure 10B 、 Figure 11B 、 Figure 12B 、 Figure 13B 、 Figure 14B and Figure 15B They are Figure 8A 、 Figure 9A 、 Figure 10A 、 Figure 11A 、 Figure 12A 、 Figure 13A 、 Figure 14A and Figure 15A Schematic diagram of the first pole piece and the second pole piece in the unfolded state in the embodiment shown.

[0050] It should be understood that the size of each part shown in the drawings is not drawn according to the actual proportional relationship.In addition, the same or similar reference numerals represent the same or similar components.

[0051] Description of reference numerals:

[0052] 10 - electrode assembly; 100 - winding structure; 11 - first pole piece; 12 - second pole piece; 11a, 12a - starting end; 11b, 12b - ending end; 131, 132 - separators; 14 - end region; 141 - edge; 15 - outer tape;

[0053] 20 - protective portion; 20a, 20a' - first starting protective portion; 20b, 20b' - second starting protective portion; 20c - first terminal protective portion; 20d - second terminal protective portion; 21 - inner protective layer; 21g - inner protective adhesive layer; 211 - first side edge; 211a - first sub-side edge; 211b - second sub-side edge; 22 - outer protective layer; 22g - outer protective adhesive layer; 221 - second side edge; 23 - extension section; 23g - extension section adhesive layer; 231 - first extension section tape substrate; 231g - first extension section adhesive layer; 232 - second extension section tape substrate; 232g - second extension section adhesive layer;

[0054] 30 - battery cell; 31 - housing; 31c - receiving chamber; 31o - opening end; 32 - end cover; 33 - collecting plate;

[0055] 40-battery; 41-box; 42-box cover

[0056] 50-vehicles;

[0057] r-winding direction; rp-reference plane. DETAILED DESCRIPTION

[0058] 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 and is in no way intended to limit the present disclosure, its application, or use. The present disclosure can be implemented in many different forms and is not limited to the embodiments described herein. These embodiments are provided to make the present disclosure thorough and complete and to fully convey the scope of the present disclosure to those skilled in the art. It should be noted that unless otherwise specifically stated, the relative arrangement of parts and steps, the composition of materials, numerical expressions, and numerical values ​​set forth in these embodiments should be interpreted as being merely exemplary and not as limiting.

[0059] In the description of the present disclosure, it should be noted that, unless otherwise specified, the meaning of "plurality" is more than two. The "first", "second" and similar words used in the present disclosure do not indicate any order, quantity or importance, but are only used to distinguish different parts. "Include" or "comprising" and similar words mean that the elements before the word include the elements listed after the word, and do not exclude the possibility of also including other elements. The directions or positional relationships indicated by "up", "down", "left", "right", "inside" and "outside" are only for the convenience of describing the present disclosure and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation of the present disclosure. When the absolute position of the object being described changes, the relative positional relationship may also change accordingly. "Vertical" is not strictly perpendicular, but is within the allowable error range. "Parallel" is not strictly parallel, but is within the allowable error range.

[0060] In the present disclosure, it should also be noted that, unless otherwise expressly specified or limited, the terms "installed," "connected," and "connected" should be understood in a broad sense. When describing a specific device as being located between a first device and a second device, there may or may not be an intervening device between the specific device and the first device or the second device. When describing a specific device as being connected to other devices, the specific device may be directly connected to the other device without an intervening device, or may not be directly connected to the other device but may have an intervening device. For another example, the connection may be a fixed connection, a detachable connection, or an integral connection.

[0061] All terms (including technical or scientific terms) used in this disclosure have the same meaning as those understood by one of ordinary skill in the art to which this disclosure belongs, unless otherwise specifically defined. It should also be understood that terms defined in, for example, general dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant technology, and should not be interpreted in an idealized or highly formal sense, unless explicitly defined herein.

[0062] Technologies, methods, and equipment known to ordinary technicians in the relevant art may not be discussed in detail, but where appropriate, the technologies, methods, and equipment should be considered part of the specification.

[0063] In some related electrode assemblies, a pole piece is provided with a tape portion formed of an insulating material at the beginning and the end, and the tape portion is aligned and glued on the inner and outer surfaces of the pole piece.

[0064] Research has found that this type of aligned adhesive tape structure creates overlapping inner and outer steps between the tape and the electrode. When the electrode assembly expands during cycling, shear stress on the electrode is also superimposed at the steps. Excessive stress at these steps can lead to cracks or even fractures in the electrode, potentially impacting the reliability of the battery cells and, in turn, the cycle life and performance of the battery.

[0065] In view of this, embodiments of the present disclosure provide a battery cell, a battery, and an electrical device, which can improve the reliability of the battery cell.

[0066] In one aspect of the present disclosure, a battery cell is provided, comprising: an electrode assembly; a shell having a accommodating cavity and an open end connected to the accommodating cavity, the accommodating cavity being configured to accommodate the electrode assembly; and an end cover covering the open end; wherein the electrode assembly comprises: a first pole sheet, a second pole sheet and an isolating member arranged between the first pole sheet and the second pole sheet, the first pole sheet, the second pole sheet and the isolating member being wound along a winding direction and forming a winding structure; wherein at least one of the first pole sheet and the second pole sheet is provided with a protective portion in an end region on 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 arranged on both sides of the end region in the thickness direction of the end region, along the winding direction, the inner protective layer has a first side located inside the edge of the end region, the outer protective layer has a second side located inside the edge of the end region, and the first side and the second side are at least partially staggered with each other in the winding direction.

[0067] A protective portion is provided in the end region of the pole piece, and the protective portion can be used to achieve protective effects such as dispersing and buffering the shear stress of the inner and outer layers of the pole piece adjacent to the end region of the pole piece. By making the first side edge of the inner protective layer and the second side edge of the outer protective layer of the protective portion at least partially staggered with each other in the winding direction, the superposition of the inner and outer steps of the inner and outer protective layers on the pole piece can be minimized or eliminated, and accordingly, the superposition of the shear stress on the pole piece formed when the electrode assembly cyclically expands at the step position can be minimized or eliminated, thereby reducing the risk of cracking or even breaking the pole piece due to excessive stress at the step position, which is beneficial to improving the reliability of the battery cell.

[0068] In the embodiments of the present disclosure, the battery cell may be a secondary battery, which refers to a battery cell that can be recharged to activate the active material after the battery cell is discharged and can continue to be used. The battery cell may be a lithium-ion battery, a sodium-ion battery, a sodium-lithium-ion battery, a lithium metal battery, a sodium metal battery, a lithium-sulfur battery, a magnesium-ion battery, a nickel-hydrogen battery, a nickel-cadmium battery, a lead-acid battery, or the like, and the embodiments of the present application do not limit this. The battery cell may be cylindrical, flat, rectangular, or in other shapes, and the embodiments of the present application do not limit this. Battery cells are generally classified into cylindrical battery cells, square battery cells, and soft-pack battery cells according to the packaging method, and the embodiments of the present application do not limit this.

[0069] The battery cells of the embodiments of the present disclosure are applicable to various types of batteries. The battery mentioned here refers to a single physical module including one or more battery cells to provide higher voltage and capacity.

[0070] In some embodiments, a battery may include a housing and a battery module. The housing provides space for the battery module, which is mounted within the housing. The housing may be made of metal. The battery module may include multiple battery cells connected in series, parallel, or in a hybrid configuration. A battery cell is the smallest unit of a battery. It includes an electrode assembly capable of undergoing an electrochemical reaction.

[0071] In some embodiments, the battery may include a case and battery cells housed in the case.

[0072] In some embodiments, the box body can be used as a part of the chassis structure of the vehicle. For example, part of the box body can become at least a part of the floor of the vehicle, or part of the box body can become at least a part of the cross beam and longitudinal beam of the vehicle.

[0073] In some embodiments, the battery may be an energy storage device, including an energy storage container, an energy storage cabinet, and the like.

[0074] The battery of the embodiment of the present disclosure can be applied to various types of battery-using electrical devices. Electrical devices can be mobile phones, portable devices, laptop computers, battery cars, electric cars, ships, spacecraft, electric toys and electric tools, etc. For example, spacecraft include airplanes, rockets, space shuttles and spacecraft, etc. Electric toys include fixed or mobile electric toys, such as game consoles, electric car toys, electric ship toys and electric airplane toys, etc. Electric tools include metal cutting power tools, grinding power tools, assembly power tools and railway power tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators and electric planers. The embodiment of the present disclosure does not impose any special restrictions on the above-mentioned electrical devices. The battery can be used to power electrical devices such as vehicles, for example, to provide power for controlling the vehicle or power for driving the vehicle.

[0075] Figure 1 Figure 5 is a schematic diagram of the structure of some embodiments of the power consumption device according to the present disclosure. For convenience, the power consumption device is described using a vehicle as an example. Vehicle 50 can be a fuel vehicle, a gas vehicle, or a new energy vehicle. The new energy vehicle can be a pure electric vehicle or a hybrid vehicle. Battery 40 can be installed at the bottom, front, or rear of vehicle 50.

[0076] The battery 40 can be used to power the vehicle 50. For example, the battery 40 can serve as the operating power source of the vehicle 50 and be used for the circuit system of the vehicle 50, such as the power requirements for starting, navigating, and operating the vehicle 50. The battery 40 can not only serve as the operating power source of the vehicle 50, but also as the driving power source of the vehicle 50, replacing or partially replacing fuel or natural gas to provide driving force for the vehicle 50.

[0077] Figure 2 is an exploded schematic diagram of some embodiments of the battery according to the present disclosure. Figure 3 Schematic diagram of some embodiments of the battery cell according to the present disclosure. Figure 2 In some embodiments, the battery 40 includes a case 41, a case cover 42, and one or more battery cells 30 disposed in the case 41. While accommodating the battery cells 30, the case 41 can also provide the battery cells 30 with functions such as cooling, sealing, and impact protection, and can also prevent liquids or other foreign matter from adversely affecting the charging, discharging, or safety of the battery cells 30. The case cover 42 can be covered on the end of the case 41 to close the case 41. The battery cells 30 are electrically connected, such as in series, in parallel, or in mixed connection, to achieve the required electrical performance parameters of the battery 40. Multiple battery cells 30 are arranged in rows, and one or more rows of battery cells 30 can be arranged in the case as needed.

[0078] In some embodiments, the battery cells 30 of the battery 40 can be arranged along at least one of the length and width of the housing. Depending on actual needs, at least one row or column of battery cells 30 can be provided. Alternatively, one or more layers of battery cells 30 can be arranged along the height of the battery 40.

[0079] In some embodiments, multiple battery cells 30 may be connected in series, parallel, or in series combination to form a battery module. The multiple battery modules are then connected in series, parallel, or in series combination to form a single unit, which is then housed within the housing 41. In other embodiments, all battery cells 30 are directly connected in series, parallel, or in series combination to form a single unit, which is then housed within the housing. The electrode terminals of the battery cells 30 may be electrically connected to adjacent battery cells 30 via busbars.

[0080] Figure 42 is a schematic cross-sectional view of the winding structure of the electrode assembly in the battery cell embodiment according to the present disclosure. Figure 5 yes Figure 4 Schematic diagram of the first pole piece and the second pole piece in the unfolded state in the embodiment shown. Figure 3-Figure 5 , an embodiment of the present disclosure provides a battery cell 30, comprising: an electrode assembly 10, a shell 31 and an end cover 32. The shell 31 has a accommodating cavity 31c and an open end 31o connected to the accommodating cavity 31c, and the accommodating cavity 31c is configured to accommodate the electrode assembly 10. The end cover 32 covers the open end 31o. The electrode assembly 10 includes: a first pole piece 11, a second pole piece 12 and an isolating member 131, 132 arranged between the first pole piece 11 and the second pole piece 12, the first pole piece 11, the second pole piece 12 and the isolating member 131, 132 are wound along a winding direction r and form a winding structure 100; wherein, at least one of the first pole piece 11 and the second pole piece 12 is provided with a protective portion 20 in the end area 14 on at least one side in the winding direction r, and the protective portion 20 has an inner protective layer 21 and an outer protective layer 22. The protective layer 22, the inner protective layer 21 and the outer protective layer 22 are respectively arranged on both sides of the end area 14 in the thickness direction of the end area 14, along the winding direction r, the inner protective layer 21 has a first side 211 located on the inner side of the edge 141 of the end area 14, and the outer protective layer 22 has a second side 221 located on the inner side of the edge 141 of the end area 14, and the first side 211 and the second side 221 are at least partially staggered with each other in the winding direction r.

[0081] The accommodating cavity 31c can be used to accommodate the electrode assembly 10 and can accommodate the electrolyte. At least one end of the shell 31 can be constructed to be open, so that the end cover 32 is provided as the open end 31o. The open end 31o allows the electrode assembly 10 to enter the accommodating cavity 31c through the open end 31o when the battery cell is installed. The shape of the shell 31 can be determined according to the shape of one or more electrode assemblies 10 accommodated in the accommodating cavity 31c. For example, the shape of the shell 31 is a hollow cuboid or a hollow cube or a hollow cylinder. The shell 31 can be made of metal (such as aluminum, aluminum alloy, etc.) and / or non-metallic material (plastic) with a certain hardness and strength.

[0082] In addition to the electrode assembly 10, end cap 32, and housing 31, the battery cell 30 also includes an electrolyte. The battery cell 30 may also include a current collecting plate 33. The current collecting plate 33 is located between the tabs of the electrode assembly 10 and the electrode terminals on the end cap 32 and can be fixedly connected to the tabs and electrode terminals by welding.

[0083] The end cap 32 is disposed at the open end 31o of the housing 31 to seal the open end 31o and, together with the housing 31, form a sealed housing cavity 31c for the electrode assembly 10. The end cap 32 can be made of a metal (e.g., aluminum, aluminum alloy, etc.) and / or a non-metallic material (plastic) with a certain degree of hardness and strength. The end cap 32 and the housing 31 can be fixedly connected by welding, bonding, or connecting with a connector. Functional components such as a liquid injection mechanism and a pressure relief mechanism can be provided on the end cap 32.

[0084] The first electrode 11 and the second electrode 12 have opposite polarities. In some embodiments, the first electrode 11 is a negative electrode and the second electrode 12 is a positive electrode. In other embodiments, the first electrode 11 is a positive electrode and the second electrode 12 is a negative electrode. During the charge and discharge process of the battery cell, active ions (such as lithium ions) are embedded and extracted back and forth between the positive electrode and the negative electrode. The separator 13 is arranged between the positive electrode and the negative electrode to prevent the positive and negative electrodes from short-circuiting while allowing active ions to pass through.

[0085] In some embodiments, the positive electrode sheet may include a positive electrode current collector substrate and a positive electrode active material layer disposed on at least one surface of the positive electrode current collector substrate.

[0086] As an example, the positive electrode current collector substrate has two surfaces facing each other in its thickness direction, and the positive electrode active material layer is provided on either or both of the two facing surfaces of the positive electrode current collector substrate.

[0087] As an example, the positive electrode current collector substrate can be a metal foil or a composite current collector. For example, as the metal foil, aluminum or stainless steel with a silver surface treatment, stainless steel, copper, aluminum, nickel, carbon electrode, carbon, nickel or titanium, etc. can be used. The composite current collector may include a polymer material base layer and a metal layer. The composite current collector can be formed by placing 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.).

[0088] As an example, the positive electrode active material layer may include at least one of the following materials: lithium-containing phosphates, lithium transition metal oxides and their respective modified compounds. However, the present disclosure is not limited to these materials, and other traditional materials that can be used as battery positive electrode active material layers may also be used. These positive electrode active material layers may be used alone or in combination of two or more. Among them, examples of lithium-containing phosphates may include but are not limited to at least one of lithium iron phosphate (such as LiFePO4 (also referred to as LFP)), a composite material of lithium iron phosphate and carbon, lithium manganese phosphate (such as LiMnPO4), a composite material of lithium manganese phosphate and carbon, lithium iron manganese phosphate, and a composite material of lithium iron manganese phosphate and carbon. Examples of lithium transition metal oxides may include but are not limited to 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 / 3Mn 1 / 3 O2 (also referred to as NCM 333 ), LiNi 0.5 Co 0.2 Mn 0.3 O2 (also referred to as NCM 523 ), LiNi 0.5 Co 0.25 Mn 0.25 O2 (also referred to as NCM 211 ), LiNi 0.6 Co 0.2 Mn 0.2 O2 (also referred to as NCM 622 ), LiNi 0.8 Co 0.1 Mn 0.1 O2 (also referred to as NCM 811 ), lithium nickel cobalt aluminum oxide (such as LiNi 0.85 Co 0.15 Al 0.05 O2) and at least one of its modified compounds, etc.

[0089] In some embodiments, the negative electrode sheet may include a negative current collector substrate.

[0090] As an example, the negative electrode current collector substrate can be a metal foil, a foamed metal, or a composite current collector. For example, as the metal foil, aluminum or stainless steel treated with silver, stainless steel, copper, aluminum, nickel, carbon electrode, carbon, nickel, or titanium can be used. The foamed metal can be nickel foam, copper foam, aluminum foam, alloy foam, or carbon foam. The composite current collector can include a polymer material base layer and a metal layer. The composite current collector can be formed by placing a metal material (copper, copper 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.).

[0091] In some embodiments, the negative electrode sheet may include a negative current collector substrate and a negative active material layer disposed on at least one surface of the negative current collector substrate.

[0092] As an example, the negative electrode current collector substrate has two surfaces facing each other in its thickness direction, and the negative electrode active material layer is provided on either or both of the two facing surfaces of the negative electrode current collector substrate.

[0093] As an example, the negative electrode active material layer may adopt the negative electrode active material layer for battery cells that is well known in the art. As an example, the negative electrode active material layer may include at least one of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, lithium titanate, etc. The silicon-based material may be selected from at least one of elemental silicon, silicon oxide compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. The tin-based material may be selected from at least one of elemental tin, tin oxide compounds, and tin alloys. However, the present disclosure is not limited to these materials, and other traditional materials that can be used as negative electrode active material layers for batteries may also be used. These negative electrode active material layers may be used alone or in combination of two or more.

[0094] In some embodiments, the material of the positive electrode current collector substrate may be aluminum, and the material of the negative electrode current collector substrate may be copper.

[0095] In some embodiments, the separator is a separator. The present disclosure has no particular limitation on the type of separator, and any known separator with a porous structure having good chemical stability and mechanical stability can be selected.

[0096] As an example, the primary material of the separator can be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene, polyvinylidene fluoride, and ceramic. The separator can be a single-layer film or a multi-layer composite film, without particular limitation. When the separator is a multi-layer composite film, the materials of each layer can be the same or different, without particular limitation. The separator can be a separate component located between the positive electrode sheet and the negative electrode sheet, or it can be located between the positive electrode sheet and the negative electrode sheet and attached to the surface of the positive electrode sheet and / or the surface of the negative electrode sheet.

[0097] In some embodiments, the separator is a solid electrolyte, which is disposed between the positive electrode and the negative electrode, and serves to transmit ions and isolate the positive and negative electrodes.

[0098] In some embodiments, the battery cell further includes an electrolyte, which acts as a conductor of ions between the positive and negative electrodes. This disclosure does not specifically limit the type of electrolyte, and the electrolyte may be selected based on needs. The electrolyte may be liquid, gel, or solid.

[0099] As an example, the liquid electrolyte includes an electrolyte salt and a solvent.

[0100] In some embodiments, the electrolyte salt can be selected from at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluorooxalatoborate, lithium dioxalatoborate, lithium difluorodioxalatophosphate, and lithium tetrafluorooxalatophosphate.

[0101] In certain embodiments, the solvent may be selected from at least one of ethylene carbonate, propylene carbonate, ethyl methyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methylpropyl carbonate, ethylpropyl 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, cyclopentane, dimethyl sulfone, methyl ethyl sulfone and diethyl sulfone. The solvent may also be an ether solvent. The ether solvent may 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, methyltetrahydrofuran, diphenyl ether and crown ether.

[0102] As an example, a gel electrolyte includes a polymer as an electrolyte skeleton network, combined with an ionic liquid-lithium salt.

[0103] As examples, the solid electrolyte includes a polymer solid electrolyte, an inorganic solid electrolyte, and a composite solid electrolyte.

[0104] As an example, the polymer solid electrolyte may be polyether (polyethylene oxide), polysiloxane, polycarbonate, polyacrylonitrile, polyvinylidene fluoride, polymethyl methacrylate, a single ion polymer, polyionic liquid-lithium salt, cellulose, or the like.

[0105] As an example, the inorganic solid electrolyte can be an oxide solid electrolyte (crystalline perovskite, sodium superconducting ion conductor, garnet, amorphous LiPON film), a sulfide solid electrolyte (crystalline lithium superion conductor (lithium germanium phosphosulfide, silver germanium sulfide), amorphous sulfide) and one or more of a halide solid electrolyte, a nitride solid electrolyte and a hydride solid electrolyte.

[0106] As an example, a composite solid electrolyte is formed by adding an inorganic solid electrolyte filler to a polymer solid electrolyte.

[0107] In some embodiments, the electrode assembly includes a main body. The main body may be the main body of a wound structure formed by winding a positive electrode sheet, a negative electrode sheet, and a separator. One or more positive electrode sheets and one or more negative electrode sheets may be provided.

[0108] refer to Figure 4 In some embodiments, a first electrode sheet 11 and a second electrode sheet 12 are separated by two separators 131 and 132 (shown by dotted lines), overlapped, and then wound in a winding direction r to form a wound structure 100. The separators on the outermost layer of the wound structure 100 are bonded and fixed by an outer layer of tape 15. In other embodiments, multiple positive electrode sheets and multiple negative electrode sheets are separated by multiple separators, overlapped, and then wound into a wound structure.

[0109] In some embodiments, the main body may be cylindrical, flat, or polygonal. A first tab and a second tab may be provided at the end of the main body. The first tab may be formed by cutting or trimming the current collector substrate of the first electrode sheet, or may be connected to the side of the current collector substrate of the first electrode sheet by welding. The second tab may be formed by cutting or trimming the current collector substrate of the second electrode sheet, or may be connected to the side of the current collector substrate of the second electrode sheet by welding.

[0110] For an embodiment in which the first electrode piece is a positive electrode piece and the second electrode piece is a negative electrode piece, the first electrode piece includes a positive electrode piece as a first electrode piece, and the second electrode piece includes a negative electrode piece as a second electrode piece. For an embodiment in which the first electrode piece is a negative electrode piece and the second electrode piece is a positive electrode piece, the first electrode piece includes a negative electrode piece as a first electrode piece, and the second electrode piece includes a positive electrode piece as a second electrode piece.

[0111] exist Figure 4 and Figure 5In the figure, along the winding direction r, the end region of the initial winding section of the first pole piece 11 is the starting end 11a, and the end region of the final winding section of the first pole piece 11 is the final winding section 11b; along the winding direction r, the end region of the initial winding section of the second pole piece 12 is the starting end 12a, and the end region of the final winding section of the second pole piece 12 is the final winding section 12b. Here, the end region of the pole piece on one side in the winding direction r refers to the region of the pole piece from the side end surface along the winding direction r (or the opposite direction of the winding direction r) to a preset distance (for example, 10 cm, 15 cm, or 20 cm, etc.).

[0112] The protective portion 20 provided at the starting end 11a of the first pole piece 11 is a first starting end protective portion 20a, the protective portion 20 provided at the end 11b of the first pole piece 11 is a first end protective portion 20c, the protective portion 20 provided at the starting end 12a of the second pole piece 12 is a second starting end protective portion 20b, and the protective portion 20 provided at the end 12b of the second pole piece 12 is a second end protective portion 20d.

[0113] For ease of understanding, Figure 5 FIG shows the unfolded state of the first pole piece 11 and the second pole piece 12. Figure 5 The first and second pole pieces 11 and 12 are shown at both ends of the winding direction r and the lengths near both ends, and the lengths in the middle are omitted by dot-dash lines. To distinguish them, the first and second pole pieces 11 and 12 are filled with different patterns.

[0114] Figure 6A This is a schematic diagram of the arrangement of a protective portion in the end region of a pole piece in some embodiments of a battery cell according to the present disclosure.

[0115] refer to Figure 5 , the protection portion 20 may be provided at least one of the first pole piece 11 and the second pole piece 12 at the beginning and the end of the winding direction. Figure 6A , any end region 14 of either the first pole piece 11 or the second pole piece 12 in the winding direction is cut off for description.

[0116] exist Figure 6A In the figure, for the pole piece corresponding to the end region 14, the upward arrow indicates the outside of the pole piece, and the downward arrow indicates the inside of the pole piece. Accordingly, the protective portion 20 has an inner protective layer 21 and an outer protective layer 22, which are respectively arranged on both sides of the end region 14 in the thickness direction.

[0117] The "inside" and "outside" here can be relative to the winding center of the winding structure 100. Inward and outward refer to the direction close to the winding center and the direction away from the winding center respectively. The inside and outside of a certain position / part refer to the side of the position / part adjacent to the winding center and the side away from the winding center respectively.

[0118] The protective portion 20 can provide protection for the end region of the electrode and other structures inside and outside it (such as the inner and outer electrode layers or isolation members). The inner protective layer 21 and the outer protective layer 22 can separate the end region of the electrode from other structures inside and outside it, so as to reduce the possible adverse effects of the end region of the electrode on other structures inside and outside it, such as the risk of burrs on the cut edge of the electrode end piercing the isolation member of the adjacent layer and causing a short circuit, thereby improving the reliability of the electrode assembly.

[0119] refer to Figure 6A , the inner protective layer 21 has a certain thickness, so the first side 211 of the inner protective layer 21 located inside the edge 141 of the end region 14 along the winding direction r (i.e., the first side 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 surface of the pole piece where the inner protective layer 21 is located. Similarly, the outer protective layer 22 has a certain thickness, so the second side 221 of the outer protective layer 22 located inside the edge 141 of the end region 14 along the winding direction r (i.e., the second side 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 surface of the pole piece where the outer protective layer 221 is located. The edge 141 here is the intersection line of the end face corresponding to the end of the end region 14 and the inner and outer surfaces of the pole piece.

[0120] During cyclic expansion of the electrode assembly, when the portion of the electrode with the inner protective layer 21 and the portion without the inner protective layer 21 are subjected to the squeezing pressure of the inner electrode layer or the insulating member, the portion of the electrode with the inner protective layer 21 is thicker, and therefore is subject to greater restriction when expanding outward than the portion of the electrode without the inner protective layer 21. This inconsistent expansion can form shear stress at the step position; similarly, when the portion of the electrode with the outer protective layer 22 and the portion without the outer protective layer 22 are subjected to the squeezing pressure of the outer electrode layer or the insulating member, the portion of the electrode with the outer protective layer 22 is thicker, and therefore is subject to greater restriction when expanding outward than the portion of the electrode without the outer protective layer 22. This inconsistent expansion can form shear stress at the step position.

[0121] In the related art, when the first side 211 and the second side 221 are aligned in the winding direction r, the steps on the inner and outer surfaces of the pole piece are also aligned accordingly, thereby forming a sudden change in thickness from the position without a protective layer to the position with a protective layer, and correspondingly superimposing a greater shear stress at the aligned step position, thereby increasing the risk of cracks or even fractures in the pole piece.

[0122] In this embodiment, the first side 211 and the second side 221 are at least partially staggered with each other in the winding direction r, which can minimize or eliminate the overlapping of the inner and outer steps of the inner protective layer and the outer protective layer on the electrode piece, so that the thickness forms a transitional change from the position without a protective layer to the position with a protective layer, thereby minimizing or eliminating the shear stress on the electrode piece formed when the electrode assembly cyclically expands at the step position, thereby reducing the risk of cracks or even fractures in the electrode piece due to excessive stress at the step position, which is beneficial to improving the reliability of the electrode assembly.

[0123] Figure 6B yes Figure 6A Schematic diagram from a top-down perspective. Figure 6B In the figure, 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 dotted line, and the first side 211 blocked by the protective portion and the pole piece is shown by a dashed line. In other words, the projections of the first side 211 and the second side 221 on a reference plane perpendicular to the thickness direction of the end region are at least partially offset from each other in the winding direction r.

[0124] An implementation form in which the first side 211 and the second side 221 are at least partially staggered with each other in the winding direction r can be seen in Figure 6A and Figure 6B In other embodiments, the first side 211 and the second side 221 may be at least partially staggered with each other in the winding direction r, and other implementation forms may also be adopted.

[0125] The specific implementation form of the stagger can be selected according to actual needs, for example, according to multiple aspects such as the polarity, length, energy density, and buffering effect on expansion pressure of the pole piece.

[0126] refer to Figure 6A and Figure 6B In some embodiments, the second side 221 is further away from the edge 141 of the end region 14 than the first side 211 in the winding direction r.

[0127] from Figure 6BIt can be seen that in the winding direction r (corresponding to the length direction of the electrode in the unfolded state), the minimum distance d1 between the first side 211 and the edge 141 is smaller than the minimum distance d2 between the second side 221 and the edge 141. Therefore, the second side 221 is farther away from the edge 141 of the end region 14 than the first side 211 in the winding direction r. In this way, this structure can form electrode surfaces with different shielding ranges in the end region of the electrode where the protective portion is provided. The inner surface of the electrode with less shielding can obtain a relatively larger effective active area, which is beneficial to improving the energy density of the electrode assembly. The outer protective layer with a larger shielding range can more effectively disperse the extrusion force during the cyclic expansion of the battery assembly, thereby reducing the risk of damage to the electrode caused by the extrusion force.

[0128] Figure 6C and Figure 6D They are schematic diagrams of the other two types of protective parts set in the end area of ​​the pole piece. Figure 6C and Figure 6D It is a reference Figure 6B The other two protection parts are provided in different ways in the end area of ​​the pole piece. Figure 6C In the figure, 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 dotted line, and the first side 211 blocked by the protective portion and the pole piece is shown by a dashed line.

[0129] refer to Figure 6C In some embodiments, the first side 211 is further away from the edge 141 of the end region 14 than the second side 221 in the winding direction r.

[0130] from Figure 6C It can be seen that in the winding direction r (corresponding to the length direction of the electrode in the unfolded state), the minimum distance d1 between the first side 211 and the edge 141 is greater than the minimum distance d2 between the second side 221 and the edge 141. Therefore, the first side 211 is farther away from the edge 141 of the end region 14 than the second side 221 in the winding direction r. In this way, this structure can form electrode surfaces with different shielding ranges in the end region of the electrode where the protective portion is provided. The outer surface of the electrode with less shielding can obtain a relatively larger effective active area, which is beneficial to improving the energy density of the electrode assembly. The inner protective layer with a larger shielding range can more effectively disperse the extrusion force during the cyclic expansion of the battery assembly, thereby reducing the risk of damage to the electrode caused by the extrusion force.

[0131] In the above embodiment, the first side edge 211 and the second side edge 221 may be straight lines, folded lines, arc lines, or a combination of folded line segments and arc lines.

[0132] refer to Figure 6DIn some embodiments, the first side 211 includes a first sub-side 211a and a second sub-side 211b, wherein the first sub-side 211a is farther away from the edge 141 of the end region 14 than the second side 221 in the winding direction r, and the second sub-side 211b is closer to the edge 141 of the end region 14 than the second side 221 in the winding direction r.

[0133] exist Figure 6D In the embodiment, the first side 211 may include different portions at different distances from the edge 141 of the end region 14, and accordingly may be in the shape of a broken line, and the second side 221 may be a straight edge or an edge of other shapes. The first side 211 and the second side 221 may intersect, such that the first sub-side is further away from the edge 141 than the corresponding portion of the second side 221, and the second sub-side is closer to the edge 141 than the corresponding portion of the second side 221. This structure can more flexibly adjust the degree of obstruction of the inner and outer surfaces of the electrode, thereby reducing shear stress while also meeting the requirements of dispersing the extrusion force and improving the energy density of the battery assembly. In addition, this structure also allows the inner and outer protective layers to have substantially the same coverage on the inner and outer sides of the electrode, thereby making the bonding strength of the inner and outer protective layers to the inner and outer surfaces of the electrode close, reducing the risk of easy detachment of the single-sided protective layer due to a large difference in bonding strength.

[0134] refer to Figure 5 and Figure 6A In some embodiments, at least one of the inner protective layer 21 and the outer protective layer 22 covers at least a portion of the edge 141 of the end region 14 .

[0135] The protective part can cover part or all of the edge 141 through the inner protective layer 21 or the outer protective layer 22, or the inner protective layer 21 and the outer protective layer 22 can jointly wrap part or all of the cover edge 141. In this way, the protective part can be used to isolate the burrs in the end area of ​​the pole piece due to cutting and other reasons from the insulating member, thereby reducing the risk of the burrs at this position piercing the insulating member and causing a short circuit between pole pieces of different polarities.

[0136] refer to Figure 6B In some embodiments, both the inner protective layer 21 and the outer protective layer 22 extend beyond the end region 14 in the width direction of the end region 14 , and the width direction of the end region 14 is perpendicular to the winding direction r.

[0137] By making the inner protective layer 21 and the outer protective layer 22 extend beyond the end region 14 in the width direction of the end region 14, an overall wrapping of the edge 141 can be formed, so that the burrs on the edge 141 can be isolated from the insulating member, thereby greatly reducing the risk of the burrs at this position piercing the insulating member and causing a short circuit between pole pieces of different polarities.

[0138] The protective portion 20 can be provided in various forms in the end region 14 of the first pole piece 11 or the second pole piece 12. For example, the protective portion 20 can be formed by attaching a tape to the pole piece surface, or by applying a protective coating to the pole piece surface.

[0139] Figure 6E yes Figure 6A Schematic diagram of the decomposition of. Figure 6A and Figure 6E In some embodiments, the inner protective layer 21 is bonded to the inner 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 surface of the end region 14 in the thickness direction of the end region 14 .

[0140] The inner surface of the end region 14 in the thickness direction of the end region 14 is the inner surface of the pole piece in the end region 14. The inner protective layer 21 is fixed to this surface by adhesive, forming a covering effect on this surface. The outer surface of the end region 14 in the thickness direction of the end region 14 is the outer surface of the pole piece in the end region. The outer protective layer 22 is fixed to this surface by adhesive, forming a covering effect on this surface.

[0141] The inner protective layer 21 and the outer protective layer 22 are bonded to the inner and outer surfaces of the end area 14 respectively by bonding, which can form a stable and reliable bonding with the pole piece, reduce the risk of falling off, and are more convenient in assembly relative to the pole piece.

[0142] refer to Figure 6E In some embodiments, the protective portion 20 includes two single-sided tapes that respectively form the inner protective layer 21 and the outer protective layer 22, and the adhesive layers of the two single-sided tapes that protrude from the edge 141 of the end area 14 are bonded to each other.

[0143] Single-sided tape may include a tape substrate and an adhesive layer disposed on one side of the tape substrate. The surface of the tape substrate facing away from the adhesive layer is a non-adhesive surface. The tape substrate may be made of materials such as polypropylene (PP), polyethylene terephthalate (PET), or polyimide (PI). The adhesive layer may be made of materials such as acrylic adhesive (PMMA adhesive).

[0144] exist Figure 6E In the figure, the inner protective adhesive layer 21g is the adhesive layer of the single-sided tape forming the inner protective layer 21, and the outer protective adhesive layer 22g is the adhesive layer of the single-sided tape forming the outer protective layer 22. Figure 6A The reference plane rp indicated by the double-dotted 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 Figure 6A In the extension section 23 on the left side of the middle reference plane rp, two single-sided tapes correspond to the first extension section adhesive layer 231g attached to the first extension section tape substrate 231 of the extension section 23 and the second extension section adhesive layer 232g attached to the second extension section tape substrate 232, which are bonded to each other, thereby forming a sealing effect on the edge 141 to reduce or eliminate the risk of burrs being exposed.

[0145] Using two single-sided tapes to form the inner protective layer 21 and outer protective layer 22 of the protective portion 20, respectively, simplifies the placement of the protective portion 20 in the end region 14 of the first electrode 11 or the second electrode 12. Single-sided tapes are easily available, and their shape and size easily meet design requirements, thereby reducing the difficulty of preparing the electrode assembly and improving its processing efficiency. Furthermore, the adhesive layers of the two single-sided tapes, which protrude from the edges 141 of the end region 14, adhere to each other, creating a tighter bond between the protective portion 20 and the end region 14, reducing the risk of detachment.

[0146] Figure 7A This is a schematic diagram of another type of protection portion provided in the end area of ​​the pole piece. Figure 7B yes Figure 7A Schematic diagram of the decomposition of. Figure 7A and Figure 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 relative portions of the adhesive layer of the single-sided tape protruding from the edge 141 of the end region 14 are bonded to each other.

[0147] Compared to Figure 6E The two single-sided tapes shown, Figure 7A and Figure 7BThe inner protective layer 21 and the outer protective layer 22 are realized by a single one-sided tape. The single-sided tape can be folded to form two opposite adhesive layers. Figure 7B In the embodiment, the inner protective adhesive layer 21g and the outer protective adhesive layer 22g are respectively the adhesive layer section for forming the inner protective layer 21 and the adhesive layer section for forming the outer protective layer 22 in the folded single-sided tape.

[0148] refer to Figure 7A The reference plane rp indicated by the double-dashed line passes through the edge 141 of the end region 14. The portion of the single-sided tape protruding from the edge 141 of the end region 14 is Figure 7A The extension section 23 on the left side of the middle reference plane rp, the single-sided tape corresponds to the extension section 23, and the relative parts of the extension section adhesive layer attached to the extension section tape base material are bonded to each other, and a sealing effect is formed on the edge 141 through the folded and bonded structure to reduce or eliminate the risk of burrs being exposed.

[0149] Using a single, folded piece of single-sided tape to form the inner and outer protective layers 21 and 22 of the protective portion 20 simplifies the placement of the protective portion 20 in the end region 14 of the first or second electrode piece 11 , 12 . Furthermore, the single-sided tape is readily available, and its shape and size easily meet design requirements, thereby reducing the difficulty of preparing the electrode assembly and improving its processing efficiency. Furthermore, the adhesion of the opposing portions of the adhesive layer of the single-sided tape protruding from the edge 141 of the end region 14 creates a tighter bond between the protective portion 20 and the end region 14 , reducing the risk of detachment.

[0150] refer to Figure 6A and Figure 7A In some embodiments, the protective portion 20 includes an extension section 23, which is located outside the edge 141 of the end area 14 along the winding direction r (that is, it protrudes relative to the edge 141 of the end area 14 in the winding direction r or the opposite direction of the winding direction r) and is connected to at least one of the inner protective layer 21 and the outer protective layer 22.

[0151] Referring to the previous embodiment in which the protective portion is implemented using single-sided tape, the extension section 23 can be the portion of the single-sided tape located outside the pole piece along 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 and not 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 formed separately and then connected.

[0152] The provision of the extension section 23 facilitates the covering and isolating function of at least one of the inner protective layer 21 and the outer protective layer 22 on the edge 141, thereby reducing the risk of the inner protective layer 21 or the outer protective layer 22 shifting relative to the electrode surface and losing their covering and isolating function on the edge 141. Furthermore, the extension section 23 can also provide support for the isolation member 13 to a certain extent.

[0153] For the electrode assembly, in different embodiments, the number, structure or location of the protective portion may be different. Figure 4 and Figure 5 In the embodiment, the protective portion 20 can be provided in the end regions 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 provided in the end regions on both sides or one side of only one of the first pole piece 11 and the second pole piece 12 in the winding direction r, or in the end regions on the same side or opposite sides of the first pole piece 11 and the second pole piece 12 in the winding direction r.

[0154] Figure 8A 、 Figure 9A 、 Figure 10A 、 Figure 11A 、 Figure 12A 、 Figure 13A 、 Figure 14A and Figure 15A 4 and 5. They are cross-sectional schematic diagrams of the winding structures of electrode assemblies according to other embodiments of the battery cell of the present disclosure. Figure 8B 、 Figure 9B 、 Figure 10B 、 Figure 11B 、 Figure 12B 、 Figure 13B 、 Figure 14B and Figure 15B They are Figure 8A 、 Figure 9A 、 Figure 10A 、 Figure 11A 、 Figure 12A 、 Figure 13A 、 Figure 14A and Figure 15A Schematic diagram of the first pole piece and the second pole piece in the unfolded state in the embodiment shown.

[0155] exist Figure 8A and Figure 8BIn the embodiment, the starting end 11a and the ending end 11b of the first pole piece 11, as well as the starting end 12a and the ending end 12b of the second pole piece 12 are provided with a protective portion 20, wherein the first starting end protective portion 20a' provided at the starting end 11a of the first pole piece 11 has a longer extension section, which extends inward to a position substantially flush with the spacers 131 and 132, and is wound into a number of windings of not less than 1. The first ending protective portion 20c provided at the ending end 11b of the first pole piece 11, and the second starting end protective portion 20b and the second ending protective portion 20d provided at the starting end 12a and the ending end 12b of the second pole piece 12 respectively, have shorter extension sections, and their extension sections are all wound into less than 1 turn.

[0156] exist Figure 9A and Figure 9B In the figure, the starting end 11a and the ending end 11b of the first pole piece 11 are provided with a protective portion 20, while the starting end 12a and the ending end 12b of the second pole piece 12 are not provided with a protective portion 20, wherein the first starting end protective portion 20a and the first ending protective portion 20c respectively provided at the starting end 11a and the ending end 11b of the first pole piece 11 have shorter extension sections, and their extension sections are both wound less than 1 turn.

[0157] exist Figure 10A and Figure 10B In the embodiment, the first pole piece 11 has a protective portion 20 at its starting end 11a and its ending end 11b, while the second pole piece 12 has no protective portion 20 at its starting end 12a and its ending end 12b. The first starting end protective portion 20a' provided at the starting end 11a of the first pole piece 11 has a longer extension section that extends inward to a position substantially flush with the spacers 131 and 132 and is wound into at least one turn. The first ending protective portion 20c provided at the ending end 11b of the first pole piece 11 has a shorter extension section that is wound into less than one turn.

[0158] exist Figure 11A and Figure 11B In the figure, the starting end 11a and the ending end 11b of the first pole piece 11 are not provided with the protective portion 20, while the starting end 12a and the ending end 12b of the second pole piece 12 are provided with the protective portion 20, wherein the second starting end protective portion 20b and the second ending protective portion 20d respectively provided at the starting end 12a and the ending end 12b of the second pole piece 12 have shorter extension sections, and their extension sections are both wound less than 1 turn.

[0159] exist Figure 12A and Figure 12BIn the embodiment, the first pole piece 11 has no protective portion 20 at its starting end 11a and its ending end 11b, while the second pole piece 12 has protective portions 20 at its starting end 12a and its ending end 12b. The second starting end protective portion 20b' provided at the starting end 12a of the second pole piece 12 has a longer extension section that extends inward and is wound into at least one turn. This extension section does not extend to a position substantially flush with the spacers 131 and 132. The second ending protective portion 20d provided at the ending end 12b of the second pole piece 12 has a shorter extension section that is wound into less than one turn.

[0160] exist Figure 13A and Figure 13B In the figure, the starting end 11a of the first pole piece 11 and the starting end 12a of the second pole piece 12 are not provided with a protective portion 20, while the end 11b of the first pole piece 11 and the end 12b of the second pole piece 12 are both provided with a protective portion 20, wherein the first end protective portion 20c provided at the end 11b of the first pole piece 11 and the second end protective portion 20d provided at the end 12b of the second pole piece 12 have shorter extension sections, and their extension sections are both wound less than 1 turn.

[0161] exist Figure 14A and Figure 14B In the figure, the starting end 11a of the first pole piece 11, the starting end 12a of the second pole piece 12 and the end 12b of the second pole piece 12 are not provided with a protective portion 20, while the end 11b of the first pole piece 11 is provided with a protective portion 20, wherein the first end protective portion 20c provided at the end 11b of the first pole piece 11 has a shorter extension section, and the extension section is wound less than 1 turn.

[0162] exist Figure 15A and Figure 15B In the figure, the starting end 11a of the first pole piece 11, the end 11b of the first pole piece 11 and the starting end 12a of the second pole piece 12 are not provided with a protective portion 20, while the end 12b of the second pole piece 12 is provided with a protective portion 20, wherein the second end protective portion 20d provided at the end 12b of the second pole piece 12 has a shorter extension section, and the extension section is wound less than 1 turn.

[0163] In the above embodiments, the first electrode 11 may be a negative electrode, the second electrode 12 may be a positive electrode, and the length of the first electrode 11 is greater than the length of the second electrode 12. In other embodiments, the first electrode 11 may be a positive electrode, and the second electrode 12 may be a negative electrode. In other embodiments, the lengths of the first electrode 11 and the second electrode 12 may be the same or different.

[0164] refer to Figure 8A 、 Figure 8B 、 Figure 10A 、 Figure 10B 、 Figure 12A and Figure 12BIn some embodiments, the protective 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 into N1 turns, where N1≥1.

[0165] Figure 8A and Figure 10A The cross-sectional structure of the first starting end protection portion 20a' provided at the starting end 11a of the first pole piece 11 in the winding direction r is shown. The first starting end protection portion 20a' has a long extension section 23, which is wound into N1 turns on the inner side, and N1≥1. Figure 12A The cross-sectional structure of the second starting end protection portion 20b' provided at the starting end 12a of the second pole piece 12 in the winding direction r is shown. The second starting end protection portion 20b' has a long extension section 23, which is wound into N1 turns on the inner side, and N1≥1.

[0166] Here N1 is not limited to a positive integer, but a positive real number greater than or equal to 1. Figure 8A and Figure 10A As can be seen in FIG, the extension section 23 can be extended to a position flush with the starting end of the isolation member 13, and can also be referred to Figure 12A The extension section 23 is not extended to a position flush with the starting end of the spacer 13 .

[0167] The extension section 23 of the protective 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 configured to be wound into a length of not less than one circle, which can effectively enhance the inner ring support strength of the winding structure 100, thereby reducing the risk of inner ring collapse.

[0168] refer to Figure 4 、 Figure 5 、 Figure 9A 、 Figure 9B 、 Figure 11A and Figure 11B In some embodiments, the protective 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 into N1 turns, wherein 0 <N1<1。

[0169] Compared to Figure 8A 、 Figure 10A and Figure 12A The corresponding embodiments are Figure 4 、 Figure 9A and Figure 11A In the embodiment, the extension section 23 of the first starting end protection portion 20a provided at the starting end 11a or the second starting end protection portion 20b provided at the starting end 12a is shorter. Here, N1 is a positive real number greater than 0 and less than 1.

[0170] The extension section 23 of the protective 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 arranged to be wound with the isolation member 13 to a length less than one turn, which is beneficial to saving material usage of the protective portion.

[0171] refer to Figure 8A and Figure 10A In some embodiments, the portion of the isolating members 131 and 132 located outside the edge of the starting end 11 a along the winding direction r is wound into N1 turns.

[0172] By winding the part of the isolator located outside the starting edge into N1 turns, the isolator and the extension section of the protective part are jointly wound N1 turns outside the starting edge, so that the extension section can support the inner ring isolator of the winding structure, enhance the inner ring support strength of the winding structure, and thus reduce the risk of inner ring collapse.

[0173] refer to Figure 4 、 Figure 9A 、 Figure 11A and Figure 12A In some embodiments, the portion of the isolating members 131 and 132 located outside the edge of the starting end 11a (or 12a) along the winding direction r is wound into N2 turns, N2>N1.

[0174] Here, N2 is a positive real number greater than N1. By winding the portion of the spacer outside the starting edge into N2 turns, which exceeds the N1 turns of the extended portion of the protective portion, the winding difficulty can be reduced and the manufacturing process can be simplified.

[0175] refer to Figure 4 、 Figure 5 and Figures 8A to 15B In some embodiments, the protective portion 20 is provided at the ends 11b and 12b 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 into N3 turns, wherein 0 <N3<1。

[0176] exist Figure 4 、 Figure 9A 、 Figure 10A 、 Figure 11A 、 Figure 12A 、 Figure 13A 、 Figure 14A and Figure 15A In the embodiment, the extension section 23 of the first end protection portion 20c provided at the end 11b or the second end protection portion 20d provided at the end 12b is wound into N3 turns on the outside and has a shorter length. Here, N3 is a positive real number greater than 0 and less than 1.

[0177] The extension section 23 of the guard portion 20, disposed at the end of at least one of the first pole piece 11 and the second pole piece 12 in the winding direction r, is configured to be wound to a length of less than one turn, thereby saving material for the guard portion. Furthermore, the shorter extension section 23 located on the outer turn can reduce the volume of the electrode assembly, thereby facilitating an increase in the energy density of the electrode assembly.

[0178] In one aspect of the present disclosure, a battery 40 is provided, comprising the battery cell 30 of any of the aforementioned embodiments. A battery using the aforementioned battery cell can achieve better reliability in use.

[0179] In one aspect of the present disclosure, an electrical device is provided, comprising the battery 40 according to any one of the aforementioned embodiments. The electrical device using the aforementioned battery can achieve better reliability.

[0180] In some specific embodiments, such as Figure 3-6B and Figure 6E As shown, the battery cell 30 includes: an electrode assembly 10, a shell 31 and an end cover 32. The shell 31 has a accommodating cavity 31c and an open end 31o connected to the accommodating cavity 31c, and the accommodating cavity 31c is configured to accommodate the electrode assembly 10. The end cover 32 covers the open end 31o. The electrode assembly 10 includes a first pole sheet 11, a second pole sheet 12 and separators 131 and 132 arranged between the first pole sheet 11 and the second pole sheet 12. The first pole sheet 11, the second pole sheet 12 and the separators 131 and 132 are wound along a winding direction r to form a winding structure 100. The first pole sheet 11 is a negative pole sheet, the second pole sheet 12 is a positive pole sheet, and the first pole sheet 11 is longer than the second pole sheet 12.

[0181] The first pole piece 11 and the second pole piece 12 are each provided with a protective portion 20 in the end regions 14 on both sides in the winding direction r. The protective portion 20 includes 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 on 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, and 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 respect to the winding direction r. The inner protective layer 21 and the outer protective layer 22 both cover the entire edge 141 of the end region 14. The protective portion 20 also includes 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 to at least one of the inner protective layer 21 and the outer protective layer 22.

[0182] The protective portion 20 includes 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 to the inner 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 surface of the end region 14 in the thickness direction of the end region 14. The adhesive layers of the two single-sided adhesive tapes that protrude from the edges 141 of the end region 14 are bonded to each other.

[0183] Thus far, various embodiments of the present disclosure have been described in detail. To avoid obscuring the concept of the present disclosure, some details known in the art have not been described. Based on the above description, those skilled in the art can fully understand how to implement the technical solutions disclosed herein.

[0184] Although some specific embodiments of the present disclosure have been described in detail through examples, those skilled in the art will understand that the above examples are for illustration only and are not intended to limit the scope of the present disclosure. Those skilled in the art will understand that the above embodiments may be modified or some technical features may be replaced with equivalents 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), characterized in that: include: an electrode assembly (10); A housing (31) having a housing cavity (31c) and an open end (31o) communicating with the housing cavity (31c), wherein the housing cavity (31c) is configured to accommodate the electrode assembly (10); and An end cover (32) covering the open end (31o); The electrode assembly (10) comprises: a first pole piece (11), a second pole piece (12), and an isolating member (131, 132) disposed between the first pole piece (11) and the second pole piece (12), wherein the first pole piece (11), the second pole piece (12), and the isolating member (131, 132) are wound along a winding direction (r) to form a winding structure (100); wherein at least one of the first pole piece (11) and the second pole piece (12) is provided with a protective portion (20) at an end region (14) on at least one side in the winding direction (r), and 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 on both sides of the end region (14) in the thickness direction of the end region (14), along the winding direction (r), the inner protective layer (21) has a first side edge (211) located inside the edge (141) of the end region (14), and the outer protective layer (22) has a second side edge (221) located inside the edge (141) of the end region (14), and the first side edge (211) and the second side edge (221) are at least partially offset from each other in the winding direction (r).

2. The battery cell (30) according to claim 1, characterized in that The first side edge (211) is further away from the edge (141) of the end region (14) than the second side edge (221) in the winding direction (r).

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

4. The battery cell (30) according to claim 1, characterized in that At least one of the inner protective layer (21) and the outer protective layer (22) covers at least a portion of an edge (141) of the end region (14).

5. The battery cell (30) according to claim 4, characterized in that The inner protective layer (21) and the outer protective layer (22) both extend beyond the end region (14) in a width direction of the end region (14), and the width direction of the end region (14) is perpendicular to the winding direction (r).

6. The battery cell (30) according to claim 4, characterized in that The protective portion (20) comprises an extension section (23), the extension section (23) being located outside an edge (141) of the end region (14) along the winding direction (r) and connected to at least one of the inner protective layer (21) and the outer protective layer (22).

7. The battery cell (30) according to claim 6, characterized in that The protective portion (20) is arranged at a 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 into N1 turns, where N1≥1.

8. The battery cell (30) according to claim 6, characterized in that The protective portion (20) is provided at a 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 into N1 turns, wherein 0 <N1<1。 9. The battery cell (30) according to claim 7 or 8, characterized in that The portion of the isolating member (131, 132) located outside the edge of the starting end (11a, 12a) along the winding direction (r) is wound into N1 turns.

10. The battery cell (30) according to claim 7 or 8, characterized in that: The portion of the isolating member (131, 132) located outside the edge of the starting end (11a, 12a) along the winding direction (r) is wound into N2 turns, where N2>N1.

11. The battery cell (30) according to claim 6, characterized in that The protective portion (20) is provided at an end (11b, 12b) 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 into N3 turns, wherein 0 <N3<1。 12. The battery cell (30) according to claim 1, characterized in that The inner protective layer (21) is bonded to the inner 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 surface of the end region (14) in the thickness direction of the end region (14).

13. The battery cell (30) according to claim 12, characterized in that The protective portion (20) comprises two single-sided adhesive tapes respectively forming the inner protective layer (21) and the outer protective layer (22), and the adhesive layers of the two single-sided adhesive tapes respectively protruding from the edge (141) of the end region (14) are bonded to each other.

14. The battery cell (30) according to claim 12, characterized in that The protective portion (20) includes a single-sided tape formed by folding the inner protective layer (21) and the outer protective layer (22), and the adhesive layers of the single-sided tape protruding from the edge (141) of the end region (14) are bonded to each other.

15. A battery (40), characterized in that Comprising the battery cell (30) according to any one of claims 1 to 14.

16. An electrical device, characterized in that: Comprising the battery (40) as claimed in claim 15.

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