Battery monomer, battery device and electric equipment

Abstract

The utility model relates to a battery monomer, a battery device and electric equipment, the battery monomer comprises an electrode assembly, the electrode assembly comprises pole pieces and separators, and the pole pieces and the separators are alternately overlapped and wound into a winding structure; the pole piece is provided with a plane section and a bent section, the pole piece comprises a current collector base material, an active substance layer and an ion transmission layer, the active substance layer is arranged on the portion, at least located on the plane section, of the current collector base material, and the ion transmission layer is arranged on the portion, located on the bent section, of the current collector base material. The ion transport layer comprises a solid electrolyte; wherein the surface of the ion transmission layer is flush with the surface of the part, which is not covered by the ion transmission layer, of the active material layer. The reliability can be improved.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the technical field of batteries, and in particular to a battery cell, a battery device and an electric equipment. BACKGROUND

[0002] Secondary batteries, especially lithium ion batteries, have the advantages of high voltage, large specific energy, long cycle life, green and pollution-free, wide working temperature range and small self-discharge, and are widely used in portable electronic devices and large new energy electric vehicles, which have great significance in solving environmental pollution and energy crisis. With the wide application of secondary ion batteries, improving the reliability of the batteries has become a problem that producers are closely concerned about. CONTENT OF THE UTILITY MODEL

[0003] In one aspect of the present disclosure, a battery cell is provided, comprising an electrode assembly, wherein the electrode assembly comprises a pole piece and a separator, and the pole piece and the separator are alternately stacked and wound into a winding structure; the pole piece has a planar section and a curved section, and the pole piece comprises a current collector substrate, an active material layer and an ion transport layer, the active material layer is arranged on at least part of the current collector substrate located in the planar section, the ion transport layer is arranged on part of the current collector substrate located in the curved section, and the ion transport layer comprises a solid-state electrolyte.

[0004] The surface of the ion transport layer is flush with the surface of the part of the active material layer not covered by the ion transport layer.

[0005] In the present embodiment, the ion transport layer comprising a solid-state electrolyte is arranged on the curved section of the pole piece in the winding electrode assembly, and the surface of the ion transport layer is flush with the surface of the part of the active material layer not covered by the ion transport layer, so that the ion transport channel is provided for the curved area of the electrode assembly by the ion transport capacity of the solid-state electrolyte itself, the insufficient electrolyte infiltration of the pole piece is improved, the phenomenon of active ion precipitation caused by stress in the curved section is effectively improved, the ion transport rate is improved, the battery polarization in the charging process is effectively reduced, and the large-rate charge and discharge capacity of the battery cell is improved. Moreover, the stress concentration of the edge of the ion transport layer is reduced by making the surface of the ion transport layer flush with the surface of the part of the active material layer not covered by the ion transport layer, the risk of cracking and even short circuit of the pole piece is reduced, and the reliability of the battery cell is effectively improved.

[0006] In some embodiments, the ion transport layer is located in at least part of the coil winding layer of the pole piece.

[0007] In the present embodiment, the ion transport layer can be arranged on a part of the bending section of the partial winding layer according to actual needs (e.g. stress distribution, etc.), so that the part of the winding layer on which the ion transport layer is arranged can effectively improve the ion transport capacity and retain more active material layers in the bending section to increase the capacity of the electrode assembly. The ion transport layer can be arranged on the bending section of all the winding layers of the pole piece, so that the ion transport capacity of the bending section can be more comprehensively improved from the inside to the outside in the winding structure.

[0008] In some embodiments, the winding layer of the pole piece on which the ion transport layer is arranged is the A th to B th winding layer of the pole piece, A is less than B, A is greater than or equal to 2 / 5 of N, and less than 3 / 5 of N, B is greater than 2 / 5 of N, and less than or equal to 3 / 5 of N, N is the total number of winding turns of the pole piece.

[0009] In the present embodiment, the ion transport layer is arranged on the A th to B th winding layer, which can effectively improve the ion transport capacity of the maximum stress region, reduce the problem of insufficient electrolyte infiltration, and retain more active material layers in the bending section to increase the capacity of the electrode assembly.

[0010] In some embodiments, the ion transport layer is arranged on at least part of the bending section along the length direction of the pole piece.

[0011] In the present embodiment, the ion transport layer can be arranged on a part of the bending section according to actual needs (e.g. stress distribution, etc.), so that the part of the bending section on which the ion transport layer is arranged can effectively improve the ion transport capacity, reduce the influence of stress and other factors, and retain more active material layers in the bending section to increase the capacity of the electrode assembly. The ion transport layer can be arranged on the entire bending section, so that the ion transport capacity of the bending section can be more comprehensively improved.

[0012] In some embodiments, the length of the ion transport layer arranged in each winding layer of the pole piece along the length direction of the pole piece is 1 / 6-1 / 2 of the length of the bending section in the corresponding winding layer.

[0013] In the present embodiment, the bending section corresponding to each winding layer includes two bending sections on both sides of the flat section, and the length of the ion transport layer is arranged to be 1 / 6-1 / 2 of the length of the bending section corresponding to the winding layer, so that the ion transport layer is arranged on the entire length or part of the length of the bending section, which can effectively balance the ion transport capacity of the corresponding region of the bending section and the increase of the capacity of the electrode assembly.

[0014] In some embodiments, the ion transport layer is continuously arranged along the length direction of the pole piece on the bending section of the pole piece, or is arranged at intervals along the length direction of the pole piece.

[0015] In the present embodiment, for each winding layer of the electrode tab provided with the ion transport layer, the ion transport layer is continuously arranged along the length direction of the electrode tab in the bending section on one side. In this way, the part of the bending section where the ion transport layer is continuously arranged can uniformly improve the ion transport capacity, and is more convenient to prepare and form. By arranging the ion transport layer in the bending section in the length direction of the electrode tab at intervals, a structure in which the ion transport layer and the active material layer are alternately arranged can be formed. In this way, the active material layer in the bending section can perform ion transport by means of the adjacent ion transport layer, improve the ion transport efficiency while taking into account the improvement of the capacity of the electrode assembly, improve the kinetic performance, effectively reduce the battery polarization during charging, and improve the large-rate charging and discharging capacity.

[0016] In some embodiments, the active material layer comprises:

[0017] a first section covering at least part of the surface of the portion of the current collector substrate located in the flat section; and

[0018] a second section covering at least part of the surface of the portion of the current collector substrate located in the bending section;

[0019] wherein the ion transport layer covers at least part of the surface of the portion of the current collector substrate located in the bending section and / or at least part of the surface of the second section.

[0020] In the present embodiment, the ions in the active material layer located in the second section of the bending section can be transported through the ion channels provided by the ion transport layer also located in the bending section, thereby obtaining higher ion transport efficiency, improving the battery polarization during charging, and reducing the ion precipitation problem caused by insufficient electrolyte infiltration, and improving the reliability of the battery cell.

[0021] In some embodiments, the thickness of the ion transport layer covering at least part of the surface of the portion of the current collector substrate located in the bending section is equal to the thickness of the second section and the first section.

[0022] In the present embodiment, by making the thickness of the ion transport layer directly covering the surface of the current collector substrate in the bending section equal to the thickness of the first section and the second section, the ion transport layer in the bending section can be more easily formed flush with the second section and the first section by coating a coating layer of uniform thickness, thereby reducing the difficulty of preparation.

[0023] In some embodiments, the thickness of the ion transport layer covering at least part of the surface of the second section is equal to the sum of the thickness of the second section covered by the ion transport layer and the thickness of the first section.

[0024] In the embodiment, the total thickness of the part of the second segment where the ion transport layer and the second segment are superimposed is the same as the thickness of the second segment without the superimposed ion transport layer, which facilitates the formation of a flush transition at the superimposed edge position, reduces the risk of stress concentration, and the ion transport layer covering part or the entire surface of the second segment can provide ion transport channels for the ions in the covered second segment, thereby improving ion transport efficiency, solving problems such as battery polarization during charging, and retaining electrolyte through the micropores to improve the problem of insufficient electrolyte infiltration.

[0025] In some embodiments, the second segments are arranged at intervals along the length direction of the pole piece, and the ion transport layer is located between adjacent two second segments.

[0026] In the embodiment, the ion transport layer located between adjacent two second segments can provide ion transport channels for the active material layer adjacent thereto through the solid-state electrolyte, and can retain a certain amount of electrolyte to reduce the case of insufficient infiltration, thereby more effectively improving the ion transport performance of the curved segment.

[0027] In some embodiments, along the length direction of the pole piece, the length L2 of each second segment at intervals is 5-10 mm, and the length L1 of the ion transport layer located between adjacent two second segments is 1-3 mm.

[0028] In the embodiment, by setting the relatively wide length L2 of the second segment and the relatively narrow length L1 of the ion transport layer, the capacity of the electrode assembly can be improved, and the ion transport capacity can be improved by using the ion transport layer adjacent to the active material layer, so that the battery cell obtains better performance.

[0029] In some embodiments, the ion transport layer further comprises a binder.

[0030] In the embodiment, by adding a binder to the ion transport layer, a film layer with certain toughness can be formed by using the viscosity of the binder, thereby improving the tensile deformation performance of the pole piece at the curved segment, reducing the risk of cracking and breaking at the curved segment and its edge position.

[0031] In some embodiments, the ion transport layer further comprises an active material.

[0032] In the embodiment, by making the ion transport layer include an active material, the pole piece at the curved segment can provide ion transport channels for the active material in the ion transport layer and the active material layer on the curved segment through the solid-state electrolyte in the ion transport layer, thereby improving ion transport efficiency, improving insufficient electrolyte infiltration of the pole piece, effectively improving the phenomenon of active ion precipitation of the curved segment due to stress; and the ion transport rate can be improved, the battery polarization during charging can be effectively reduced, and the large-rate charging and discharging capacity of the battery cell can be improved.

[0033] In some embodiments, the D50 of the solid-state electrolyte powder particles is 220-280 nm.

[0034] For the ion transport layer, when the average particle size of the solid-state electrolyte contained therein reaches the value range of 220-280 nm, the solid-state electrolyte can be more easily and uniformly distributed in the ion transport layer, and for the ion transport layer also containing an active material, the solid-state electrolyte can also wrap the active molecules, thereby improving the ion transport performance.

[0035] In some embodiments, the battery cell further comprises a shell and an electrolyte, and the electrode assembly and the electrolyte are accommodated in an inner cavity of the shell.

[0036] In the height direction of the shell, the lateral width W1 of the ion transport layer at a position close to the bottom of the shell is less than or equal to the lateral width W2 of the ion transport layer at a position close to the top of the shell.

[0037] In the present embodiment, considering that the electrolyte is affected by gravity and is more at the bottom of the shell, in order to improve the ion transport effect on the top side, by making the lateral width W1 of the ion transport layer at a position close to the bottom of the shell less than the lateral width W2 of the ion transport layer at a position close to the top of the shell, the solid-state electrolyte close to the top of the shell can be increased to improve the condition that the amount of electrolyte at the top is relatively small, thereby making the ion transport performance more uniform in the height direction of the shell.

[0038] In one aspect of the present disclosure, a battery device is provided, comprising the battery cell as described above.

[0039] The battery device comprising the battery cell of the foregoing embodiments can achieve better reliability.

[0040] In one aspect of the present disclosure, a power-consuming device is provided, comprising the battery device as described above.

[0041] The power-consuming device comprising the battery device of the foregoing embodiments can achieve better reliability. BRIEF DESCRIPTION OF DRAWINGS

[0042] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the present disclosure and, together with the description, serve to explain the principles of the present disclosure.

[0043] The present disclosure can be more clearly understood and appreciated from the following detailed description, taken in conjunction with the following drawings of which:

[0044] Figure 1 is a structural schematic diagram of some embodiments of the power-consuming device according to the present disclosure;

[0045] Figure 2is an exploded structural schematic view of some embodiments of a battery device according to the present disclosure;

[0046] Figure 3 is an exploded structural schematic view of some embodiments of a battery cell according to the present disclosure;

[0047] Figure 4 is a schematic view of the winding structure of an electrode assembly in some embodiments of a battery cell according to the present disclosure;

[0048] Figure 5 is a cross-sectional schematic view of a portion taken from a planar segment and a curved segment of a certain turn of electrode tab in some embodiments of a battery cell according to the present disclosure;

[0049] Figure 6 is a cross-sectional schematic view of a portion taken from a planar segment and a curved segment of a certain turn of electrode tab in some embodiments of a battery device according to the present disclosure;

[0050] Figure 7 is a schematic view of a portion of a winding layer in which an ion transport layer is located on a curved segment in some embodiments of a battery cell according to the present disclosure;

[0051] Figure 8 is a schematic view of a portion of a winding layer in which an ion transport layer is located on a curved segment over a partial length range in some embodiments of a battery cell according to the present disclosure;

[0052] Figure 9 is a schematic view of a portion of a winding layer in which an ion transport layer is located on a curved segment over an entire length range in some embodiments of a battery cell according to the present disclosure;

[0053] Figure 10 is a schematic view of a winding layer in which an ion transport layer entirely covers an active material layer of a curved segment in some embodiments of a battery device according to the present disclosure;

[0054] Figure 11 is a cross-sectional schematic view of a winding layer in which an ion transport layer is spaced apart along the length direction of an electrode tab in some embodiments of a battery cell according to the present disclosure;

[0055] Figure 12 and Figure 13 are schematic views of the lateral width distribution of an ion transport layer on an electrode tab in some embodiments of a battery cell according to the present disclosure, respectively.

[0056] It should be understood that the dimensions of the various portions shown in the drawings are chosen for sake of convenience and are not necessarily to scale. Furthermore, identical or similar reference numerals are used to denote identical or similar components.

[0057] BRIEF DESCRIPTION OF DRAWINGS

[0058] 100, battery cell; 10, electrode assembly; 11, electrode sheet; 11a, positive electrode sheet; 11b, negative electrode sheet; 11t, tab; 111, flat section; 112, curved section; 113, current collector substrate; 114, active material layer; 1141, first section; 1142, second section; 115, ion transport layer; 12, separator;

[0059] 21, case; 22, top cover; 23, first current collecting disc; 24, second current collecting disc; 25, first pole; 26, second pole; 27, liquid injection hole; 28, explosion-proof valve;

[0060] 30, battery device; 31, box; 32, box cover;

[0061] 40, vehicle; 41, controller; 42, motor; 43, axle; 44, wheel. DETAILED DESCRIPTION

[0062] The embodiments of the technical solutions of the present disclosure will be described in detail below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solutions of the present disclosure, and therefore only serve as examples, and cannot limit the protection scope of the present disclosure.

[0063] Unless otherwise defined, all technical and scientific terms used in the present disclosure have the same meanings as commonly understood by one of ordinary skill in the art to which the present disclosure belongs; the terms used in the present disclosure are only for the purpose of describing specific embodiments and are not intended to limit the present disclosure; the terms "include" and "have" and any variations thereof in the specification and claims of the present disclosure and the above description of drawings are intended to cover non-exclusive inclusion.

[0064] In the description of the embodiments of the present disclosure, the technical terms "first", "second", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present disclosure, the meaning of "a plurality of" is two or more, unless otherwise explicitly and specifically limited.

[0065] In the present disclosure, the phrase "embodiment" means that the specific features, structures or properties described in conjunction with the embodiment can be included in at least one embodiment of the present disclosure. The appearance of this phrase at various places in the specification does not necessarily mean the same embodiment, nor is it an independent or alternative embodiment to other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described in the present disclosure can be combined with other embodiments.

[0066] In the description of the embodiments of the present disclosure, the term "and / or" is only a description of the association relationship of associated objects, that is, there can be three relationships, for example, A and / or B, which can represent the three cases of A existing alone, A and B existing simultaneously, and B existing alone. In addition, if the character " / " appears in the present disclosure, it generally indicates that the front and rear associated objects are in an "or" relationship.

[0067] In the description of the embodiments of the present disclosure, the term "a plurality of" refers to two or more (including two), and similarly, "a plurality of groups" refers to two or more groups (including two groups), and "a plurality of pieces" refers to two or more pieces (including two pieces).

[0068] In the description of the embodiments of the present disclosure, the term "at least one" refers to one or more than two (including two), and similarly, "at least one group" refers to one group or more than two groups (including two groups), and "at least one piece" refers to one piece or more than two pieces (including two pieces). In the description of the embodiments of the present disclosure, the term "at least part" refers to part or all.

[0069] Unless specifically stated, in the description of the embodiments of the present disclosure, the technical terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, which is only for the convenience of describing the embodiments of the present disclosure and simplifying the description, and does not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the embodiments of the present disclosure.

[0070] In the description of the embodiments of the present disclosure, unless otherwise specifically stated and limited, the technical terms "mounting", "connecting", "connecting", "fixing" and the like should be understood in a broad sense, for example, it can be fixedly connected, or it can be detachably connected, or it can be integrated; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the communication or interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the embodiments of the present disclosure can be understood according to the specific circumstances.

[0071] Some embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings. The features in the following embodiments can be combined with each other without conflict.

[0072] For the wound type battery cell, the interlayer pores in the corner region are consumed during the aging expansion, so that the middle circle part of the corner is subjected to greater compressive stress, which is easy to cause insufficient impregnation of the pole piece, worsen the dynamic performance, and thus is easy to cause lithium precipitation. In order to improve the problem of poor electrolyte impregnation in the corner region of the wound type battery cell, some related technologies coat a plurality of protruding ion conductive layers on the surface of the active material layer in the corner region to improve the conductive effect of the corner region.

[0073] It is found through research that the outer circle of the corner region of the wound type battery cell is subjected to greater tensile stress, and the pole piece may have a risk of cracking due to insufficient plastic deformation capacity, and the edge region of the protruding ion conductive layer may form stress concentration on the surface of the pole piece, so that the pole piece is more likely to crack, even short-circuit, thereby affecting the reliability of the battery cell.

[0074] Therefore, the embodiments of the present disclosure provide a battery cell, a battery device and an electric equipment, which can improve the reliability of the battery cell.

[0075] In one aspect of the present disclosure, a battery cell is provided, comprising an electrode assembly, wherein the electrode assembly comprises a pole piece and a separator, the pole piece and the separator are alternately stacked and wound into a wound structure; the pole piece has a planar section and a curved section, the pole piece comprises a current collector substrate, an active material layer and an ion transport layer, the active material layer is arranged on the current collector substrate at least on the part of the planar section, the ion transport layer is arranged on the current collector substrate on the part of the curved section, and the ion transport layer comprises a solid-state electrolyte.

[0076] The surface of the ion transport layer is flush with the surface of the part of the active material layer not covered by the ion transport layer.

[0077] In the present embodiment, the ion transport layer comprising a solid-state electrolyte is arranged on the curved section of the pole piece in the wound electrode assembly, and the surface of the ion transport layer is flush with the surface of the part of the active material layer not covered by the ion transport layer, so that the ion transport channel is provided for the curved region of the electrode assembly by the ion transport ability of the solid-state electrolyte itself, the insufficient impregnation of the pole piece by electrolyte is improved, and the phenomenon of active ion precipitation caused by stress in the curved section is effectively improved; and the ion transport rate is improved, the battery polarization during charging process is effectively reduced, and the large rate charge and discharge capacity of the battery cell is improved. Moreover, the stress concentration of the edge region of the ion transport layer is reduced by the surface of the ion transport layer being flush with the surface of the part of the active material layer not covered by the ion transport layer, the risk of cracking of the pole piece is reduced, and even the risk of short-circuit is reduced, thereby effectively improving the reliability of the battery cell.

[0078] In the embodiments of the present disclosure, the battery cell can be a secondary battery, which refers to a battery cell that can be used continuously by activating the active material through charging after discharging.

[0079] The battery cell can be a lithium ion battery, a sodium ion battery, a sodium lithium ion battery, a lithium metal battery, a sodium metal battery, a lithium sulfur battery, a magnesium ion battery, a nickel-hydrogen battery, a nickel-cadmium battery, a lead-acid battery, etc., and the embodiments of the present disclosure are not limited thereto. The battery cell can be in the shape of a cylinder, a flat body, a cuboid, or other shapes, and the embodiments of the present disclosure are not limited thereto. The battery cell is generally classified into a cylindrical battery cell, a square battery cell, and a soft-pack battery cell according to the packaging method, and the embodiments of the present disclosure are not limited thereto.

[0080] The battery cell of the embodiments of the present disclosure can be applied to various battery devices. The battery device referred to herein refers to a single physical module including one or more battery cells to provide higher voltage and capacity.

[0081] In some embodiments, the battery device can include a box body and a battery cell, and the battery cell is accommodated in the box body.

[0082] In some embodiments, the battery device can include a box body and a battery module, and the box body is used to provide an accommodation space for the battery module, and the battery module is installed in the box body. The box body can be made of metal material. The battery module can include a plurality of battery cells connected in series, in parallel, or in a mixed manner.

[0083] In some embodiments, the box body can be part of the chassis structure of the vehicle. For example, part of the box body can be at least part of the floor of the vehicle, or part of the box body can be at least part of the cross beam and the longitudinal beam of the vehicle.

[0084] In some embodiments, the battery device can be an energy storage device. The energy storage device includes an energy storage container, an energy storage cabinet, etc.

[0085] The battery device of the embodiments of the present disclosure can be applied to various power consuming equipment using the battery device. The power consuming equipment can be a mobile phone, a portable device, a notebook computer, an electric vehicle, an electric vehicle, a ship, a spacecraft, an electric toy, and an electric tool, etc. For example, the spacecraft includes an airplane, a rocket, a space shuttle, and a spacecraft, etc. The electric toy includes a fixed or mobile electric toy, such as a game console, an electric vehicle toy, an electric ship toy, and an electric airplane toy, etc. The electric tool includes a metal cutting electric tool, a grinding electric tool, an assembly electric tool, and a railway electric tool, such as a power drill, a power grinder, a power wrench, a power screwdriver, an electric hammer, an impact drill, a concrete vibrator, and an electric planer. The embodiments of the present disclosure do not particularly limit the above-mentioned power consuming equipment.

[0086] Figure 1is a structural schematic diagram of some embodiments of an electrical equipment according to the present disclosure. For convenience, the electrical equipment is taken as a vehicle for example. The vehicle 40 can be a fuel automobile, a gas automobile or a new energy automobile, and the new energy automobile can be a pure electric vehicle or a hybrid electric vehicle, etc. The battery device 30 can be arranged at the bottom or the front or the rear of the vehicle 40.

[0087] The battery device 30 can be used for power supply of the vehicle 40, for example, the battery device 30 can be used as an operating power source of the vehicle 40, for example, for the circuit system of the vehicle 40, for example, for the starting, navigation and working power demand of the vehicle 40. The battery device 30 can not only be used as an operating power source of the vehicle 40, but also be used as a driving power source of the vehicle 40, to replace or partially replace the fuel or natural gas to provide driving force for the vehicle 40.

[0088] The inside of the vehicle 40 can also be provided with an axle 43, a wheel 44, a motor 42 and a controller 41, the controller 41 being used to control the battery device 30 to supply power to the motor 42, for example, when the vehicle 40 uses the battery device 30 as a driving power source, the controller 41 can provide the required power for the motor 42 at a uniform speed or acceleration. The motor 42 is used to drive the axle 43 to rotate, so as to drive the wheel 44 to rotate.

[0089] Figure 2 is a disassembled schematic diagram of some embodiments of the battery device according to the present disclosure. Referring to Figure 2 In some embodiments, the battery device 30 includes a box body 31, a box cover 32 and one or more battery monomers 100 arranged in the box body 31. The box body 31 can not only accommodate the battery monomers 100, but also provide functions such as cooling, sealing and impact protection for the battery monomers 100, and can also avoid the adverse effects of liquid or other foreign matters on the charging and discharging or reliability of the battery monomers 100. The box cover 32 can be covered on the end of the box body 31 to close the box body 31.

[0090] In Figure 2 , the battery monomers 100 can be electrically connected in series, in parallel or in a mixed manner, etc. to achieve the required electrical performance parameters of the battery device 30. The plurality of battery monomers 100 are arranged in rows, and one row or more rows of battery monomers 100 can be arranged in the box body according to needs.

[0091] In some embodiments, the battery monomers 100 of the battery device 30 can be arranged along at least one of the length direction and the width direction of the box body 31. According to actual needs, at least one row or one column of battery monomers 100 can be arranged. According to needs, one layer or more layers of battery monomers 100 can also be arranged in the height direction of the battery device 30.

[0092] In some embodiments, a plurality of battery cells 100 can be first connected in series or in parallel or in a hybrid manner to form a battery module, and then a plurality of battery modules can be connected in series or in parallel or in a hybrid manner to form a whole, which is accommodated in the box 31. In other embodiments, all battery cells 100 are directly connected in series or in parallel or in a hybrid manner, and then the whole formed by all battery cells 100 is accommodated in the box 31. The electrode terminals of the battery cells 100 can be electrically connected to adjacent battery cells 100 through busbars.

[0093] Figure 3 is a schematic diagram of the exploded structure of some embodiments of the battery cell according to the present disclosure. Figure 4 is a schematic diagram of the winding structure of the electrode assembly in some embodiments of the battery cell according to the present disclosure. Figure 5 is a schematic diagram of the cross section of a part taken from the planar section and the curved section of a certain pole piece according to some embodiments of the battery cell according to the present disclosure. Figure 6 is a schematic diagram of the cross section of a part taken from the planar section and the curved section of a certain pole piece according to some other embodiments of the battery device according to the present disclosure.

[0094] With reference to Figures 3-6 , the embodiments of the present disclosure provide a battery cell 100, comprising an electrode assembly 10, wherein the electrode assembly 10 comprises pole pieces 11 and separators 12, the pole pieces 11 and the separators 12 are alternately stacked and wound into a winding structure; the pole piece 11 has a planar section 111 and a curved section 112, the pole piece 11 comprises a current collector substrate 113, an active material layer 114 and an ion transport layer 115, the active material layer 114 is arranged on at least part of the current collector substrate 113 located in the planar section 111, the ion transport layer 115 is arranged on part of the current collector substrate 113 located in the curved section 112, and the ion transport layer 115 comprises a solid-state electrolyte. The surface of the ion transport layer 115 is flush with the surface of the part of the active material layer 114 not covered by the ion transport layer 115.

[0095] The electrode assembly 10 can comprise two kinds of pole pieces 11, namely positive pole pieces 11a and negative pole pieces 11b. The separators 12 are located between the positive pole pieces 11a and the negative pole pieces 11b. The working of the electrode assembly 10 is realized by the movement of internal metal ions between the positive pole pieces 11a and the negative pole pieces 11b. During the charging and discharging of the battery cell, active ions (such as lithium ions) are embedded and extracted between the positive pole pieces 11a and the negative pole pieces 11b. The separators 12 arranged between the positive pole pieces 11a and the negative pole pieces 11b can prevent the short circuit of the positive and negative poles, and at the same time allow the active ions to pass through.

[0096] As Figure 4As shown, the two pole pieces 11 are alternately stacked with the separator 12 and wound into a wound structure. For the wound structure in flat form, the whole can be divided into flat portions and circular arc corner portions on both sides of the flat portions. As shown in Figure 5 and Figure 6 As shown, the pole piece 11 also has a planar segment 111 and a curved segment 112 corresponding to the flat portions and the circular arc corner portions of the wound structure, respectively.

[0097] Referring to Figure 5 and Figure 6 The pole piece 11 includes a current collector substrate 113, an active material layer 114, and an ion transport layer 115. The pole piece 11 including the ion transport layer 115 can be a positive pole piece 11a or a negative pole piece 11b. Both the positive pole piece 11a and the negative pole piece 11b can include the ion transport layer.

[0098] The active material layer 114 is disposed on the portion of the current collector substrate 113 located in the planar segment 111. In some embodiments, the active material layer 114 can also be partially disposed on the portion of the current collector substrate 113 located in the curved segment 112. In other embodiments, the active material layer 114 can not be disposed on the portion of the current collector substrate 113 located in the curved segment 112.

[0099] For the positive pole piece 11a, the current collector substrate 113 and the active material layer 114 included therein are a positive current collector substrate and a positive active material layer, respectively. The positive active material layer is disposed on the surface of the positive current collector substrate. For example, the positive active material layer can be disposed on one side surface or both side surfaces in the thickness direction of the positive current collector substrate.

[0100] As an example, the positive current collector substrate can be a metal foil or a composite current collector. For example, as the metal foil, silver surface-treated aluminum or stainless steel, stainless steel, copper, aluminum, nickel, a carbon electrode, carbon, nickel, or titanium, etc. can be used. The composite current collector can include a polymer material base layer and a metal layer. The composite current collector can be formed by forming 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.).

[0101] As an example, the positive electrode active material layer can include at least one of a lithium-containing phosphate, a lithium transition metal oxide, and a modified compound of each thereof. However, the present disclosure is not limited to these materials, and other conventional materials that can be used as a positive electrode active material layer can also be used. These positive electrode active material layers can be used alone only one or two or more can be used in combination. Among them, examples of the lithium-containing phosphate can include, but are not limited to, at least one of lithium iron phosphate (such as LiFeP04 (which can also be referred to as LFP)), a composite material of lithium iron phosphate and carbon, lithium manganese phosphate (such as LiMnP04), a composite material of lithium manganese phosphate and carbon, lithium manganese iron phosphate, and a composite material of lithium manganese iron phosphate and carbon. Examples of the lithium transition metal oxide can include, but are not limited to, at least one of lithium cobalt oxide (such as LiCo02), lithium nickel oxide (such as LiNi02), lithium manganese oxide (such as LiMn02, LiMn204), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide (such as LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2 (which can also be referred to as NCM 333 ), LiNi 0.5 Co 0.2 Mn 0.3 O2 (which can also be referred to as NCM 523 ), LiNi 0.5 Co 0.25 Mn 0.25 O2 (which can also be referred to as NCM 211 ), LiNi 0.6 Co 0.2 Mn 0.2 O2 (which can also be referred to as NCM 622 ), LiNi 0.8 Co 0.1 Mn 0.1 O2 (which can also be referred to as NCM 811 ), lithium nickel cobalt aluminum oxide (such as LiNi 0.85 Co 0.15 Al 0.05 O2), a modified compound thereof, and the like.

[0102] For the negative electrode tab 11b, the current collector substrate 113 and the active material layer 114 included therein are a negative electrode current collector substrate and a negative electrode active material layer, respectively. The negative electrode active material layer is provided on the surface of the negative electrode current collector substrate. For example, the negative electrode active material layer can be provided on one side surface or both side surfaces in the thickness direction of the negative electrode current collector substrate.

[0103] As an example, the negative current collector substrate can employ a metal foil, a foam metal, or a composite current collector. For example, as a metal foil, silver surface-treated aluminum or stainless steel, stainless steel, copper, aluminum, nickel, a carbon electrode, or the like can be employed. The foam metal can be a foam nickel, a foam copper, a foam aluminum, a foam alloy, or a foam carbon, or the like. The composite current collector can include a polymer material base layer and a metal layer. The composite current collector can be formed by applying a metal material (copper, a copper alloy, nickel, a nickel alloy, titanium, a titanium alloy, silver, and a silver alloy, or the like) on a polymer material base (such as a base of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, or the like).

[0104] As an example, the negative active material layer can employ a negative active material layer for a battery cell known in the art. As an example, the negative active material layer can include at least one of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, a silicon-based material, a tin-based material, and lithium titanate, or the like. The silicon-based material can be selected from at least one of elemental silicon, a silicon oxide compound, a silicon-carbon composite, a silicon-nitrogen composite, and a silicon alloy. The tin-based material can be selected from at least one of elemental tin, a tin oxide compound, and a tin alloy. However, the present disclosure is not limited to these materials, and other conventional materials that can be used as a negative active material layer can also be used. These negative active material layers can be used alone or in combination with two or more.

[0105] For the positive electrode sheet or the negative electrode sheet, the material of the corresponding active material layer can employ a composition of a conventional material and a conventional ratio, which is not particularly limited here.

[0106] In some embodiments, the separator 12 is a separator film. The present disclosure does not particularly limit the type of separator film, and the separator 12 can employ any known porous structure separator film having good chemical stability and mechanical stability.

[0107] As an example, the main material of the separator film can be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene, polyvinylidene fluoride, and ceramic. The separator film can be a single layer film or a multi-layer composite film, which is not particularly limited. When the separator film is a multi-layer composite film, the materials of the respective layers can be the same or different, which is not particularly limited. The separator film can be a separate component located between the positive electrode sheet 11a and the negative electrode sheet 11b, or can be attached to the surface of the positive electrode sheet 11a and / or the surface of the negative electrode sheet 11b while being located between the positive electrode sheet 11a and the negative electrode sheet 11b.

[0108] The ion transport layer 115 includes a solid electrolyte. The solid electrolyte can be at least one of an oxide solid electrolyte, a sulfide solid electrolyte, and a polymer electrolyte. The ion transport layer 115 containing the solid electrolyte is disposed on the curved section 112 of the electrode 11, providing an ion transport channel for the curved section 112 and improving the ion transport rate. The ion transport layer 115 can be, but is not limited to, a coating, and its surface can have a certain number of micropores to help the curved section 112 retain the electrolyte and reduce the problem of insufficient wetting due to electrolyte pressure.

[0109] An ion transport layer 115 is disposed on the portion of the current collector substrate 113 located in the curved section 112. It may be located on the entire portion of the current collector substrate 113 located in the curved section 112, or it may be located on a portion of the entire portion of the current collector substrate 113 located in the curved section 112.

[0110] The material of the ion transport layer can use conventional materials with conventional proportions, and there are no special restrictions here.

[0111] like Figure 5 and Figure 6 As shown, the surface of the ion transport layer 115 is flush with the surface of the portion of the active material layer 114 not covered by the ion transport layer 115. In the curved section 112 of the electrode 11, the ion transport layer 115 can be directly disposed on the surface of the current collector substrate 113 or on the surface of the active material layer 114. Regardless of the form, the surface of the ion transport layer 115 is flush with the surface of the active material layer 114 not covered by it.

[0112] For the ion transport layer 115 and the adjacent active material layer 114, the distances between them and the surface of the current collector substrate 113 are the same, thereby forming a flush transition at the junction and minimizing stress concentration at this transition.

[0113] In the present embodiment, the ion transport layer 115 including solid-state electrolyte is arranged on the bent section 112 of the electrode tab 11 in the wound electrode assembly, and the surface of the ion transport layer 115 is flush with the surface of the portion of the active material layer 114 that is not covered by the ion transport layer 115, so that the ion transport channel is provided for the bent area of the electrode assembly by the ion transport capability of the solid-state electrolyte itself, the insufficient electrolyte impregnation of the electrode tab is improved, the phenomenon of active ion precipitation of the bent section due to stress is effectively improved, the ion transport rate is improved, the battery polarization during charging is effectively reduced, and the large-rate charge and discharge capacity of the battery cell is improved. Moreover, the stress concentration of the edge of the ion transport layer is reduced by the flush surface of the ion transport layer and the surface of the portion of the active material layer that is not covered by the ion transport layer, the risk of cracking or even short circuit of the electrode tab is reduced, and the reliability of the battery cell is effectively improved.

[0114] In some embodiments, the ion transport layer 115 further includes an active material.

[0115] The active material included in the ion transport layer 115 can be the same as or different from the active material included in the active material layer 114. The active material in the ion transport layer 115 can refer to the related description of the active material layer 114 above, which will not be repeated here. In other embodiments, the ion transport layer 115 can also not include an active material.

[0116] In the present embodiment, by including an active material in the ion transport layer 115, the electrode tab 11 in the bent section 112 can provide an ion transport channel for the active material in the ion transport layer 115 and the active material layer 114 on the bent section 112 through the solid-state electrolyte in the ion transport layer 115, improve the ion transport efficiency, improve the insufficient electrolyte impregnation of the electrode tab, effectively improve the phenomenon of active ion precipitation of the bent section due to stress, and improve the ion transport rate, effectively reduce the battery polarization during charging, and improve the large-rate charge and discharge capacity of the battery cell.

[0117] In some embodiments, the powder particle D50 of the solid-state electrolyte is 220-280 nm.

[0118] The powder particle D50 of the solid-state electrolyte can be selected as 220-280 nm, such as 220 nm, 235 nm, 254 nm, 265 nm, 280 nm, etc. For the ion transport layer 115, the average particle size of the solid-state electrolyte included therein reaches this value range, which can be more easily and uniformly distributed in the ion transport layer 115, and for the ion transport layer 115 also containing an active material, the solid-state electrolyte can also wrap the active molecules to improve the ion transport performance.

[0119] In some embodiments, the ion transport layer 115 further includes a binder.

[0120] The binder includes at least one of polyvinylidene fluoride (PVDF), styrene butadiene rubber, carboxymethyl cellulose salt (e.g., sodium carboxymethyl cellulose), polyacrylic acid, polyacrylonitrile, and polyacrylate. The ion transport layer 115 including the binder can have a thickness of 10-20 μm, which can improve the plastic deformation performance of the material.

[0121] Considering that the continuous swelling of the electrode assembly can easily cause the corner region of the outer ring and the tangent position of the planar region to crack, the ion transport layer 115 including the binder is disposed adjacent to the planar segment 111 of the curved segment 112, which can improve the strength of the position where the curved segment 112 and the planar segment 111 meet, so that the position is not easily cracked. Moreover, unlike the active material, the binder generally does not swell during the aging process, which can also effectively delay the cracking time of the electrode sheet.

[0122] In the present embodiment, by adding the binder to the ion transport layer 115, a film layer having a certain toughness can be formed by the adhesion of the binder, so that the tensile deformation performance of the electrode sheet 11 at the curved segment 112 can be improved, and the risk of cracking and breaking of the curved segment 112 and the edge position thereof can be reduced.

[0123] Reference Figure 5 and Figure 6 In some embodiments, the active material layer 114 includes a first segment 1141 and a second segment 1142. The first segment 1141 covers at least part of the surface of the portion of the current collector substrate 113 located at the planar segment 111. The second segment 1142 covers at least part of the surface of the portion of the current collector substrate 113 located at the curved segment 112. The ion transport layer 115 covers at least part of the surface of the portion of the current collector substrate 113 located at the curved segment 112 and / or at least part of the surface of the second segment 1142.

[0124] The active material layer 114 can be distributed only on the planar segment of the electrode sheet 11, or can be distributed both on the planar segment 111 and on the curved segment 112. The portion of the active material layer 114 located at the planar segment 111 is the first segment 1141, and the portion located at the curved segment 112 is the second segment 1142. The ion transport layer 115 can cover the surface of the portion of the current collector substrate 113 located at the curved segment 112 as shown in Figure 5 or can cover part of the surface of the second segment 1142 of the active material layer 114 located at the curved segment 112 as shown in Figure 6

[0125] ​In the present embodiment, the active material layer 114 is located in the second section 1142 of the curved section 112, and ions can pass through the ion channel provided by the ion transport layer 115 also located in the curved section 112, so as to obtain higher ion transport efficiency, improve the problems of battery polarization during charging process, and reduce the problem of ion precipitation caused by insufficient electrolyte infiltration, and improve the reliability of the battery cell.

[0126] Reference Figure 5 In some embodiments, the thickness of the ion transport layer 115 covering at least part of the surface of the portion of the current collector substrate 113 located in the curved section 112 is equal to the thickness of the second section 1142 and the first section 1141.

[0127] Figure 5 The ion transport layer 115 can directly cover part of the surface of the portion of the current collector substrate 113 located in the curved section 112 by coating or the like, or can cover the entire surface of the portion of the current collector substrate 113 located in the curved section 112. In this case, the distance between the surface of the ion transport layer 115 and the surface of the current collector substrate 113 is the thickness of the ion transport layer 115, and the first section 1141 and the second section 1142 of the active material layer 114 are also directly coated on the surface of the portion of the current collector substrate 113 located in the flat section 111 and the curved section 112 by coating or the like, respectively, and the distance between them and the surface of the current collector substrate 113 is the thickness of the first section 1141 and the second section 1142 of the active material layer 114, respectively.

[0128] In the present embodiment, by making the thickness of the ion transport layer 115 directly covering the surface of the current collector substrate 113 in the curved section 112 equal to the thickness of the first section 1141 and the second section 1142, the ion transport layer 115 in the curved section 112 can be more easily formed flush with the second section 1142 and the first section 1141 by coating a coating layer of uniform thickness, thereby reducing the difficulty of preparation.

[0129] Reference Figure 6 In some embodiments, the thickness of the ion transport layer 115 covering at least part of the surface of the second section 1142 is equal to the sum of the thickness of the second section 1142 covered by the ion transport layer 115 and the thickness of the first section 1141.

[0130] Figure 5The ion transport layer 115 can cover a part of the surface of the second section 1142 of the active material layer 114 by coating or the like. The distance of the surface of the ion transport layer 115 covering a part of the second section 1142 from the surface of the current collector substrate 113 is the sum of the thickness of the ion transport layer 115 and the thickness of the part of the second section 1142 covered by the ion transport layer 115. The distance of the surface of the part of the second section 1142 not covered by the ion transport layer 115 from the surface of the current collector substrate 113 is the thickness of the part of the second section 1142 not covered by the ion transport layer 115.

[0131] In the present embodiment, the total thickness of the part of the second section 1142 where the ion transport layer 115 and the second section 1142 overlap in the curved section 112 is the same as the thickness of the second section 1142 not overlapping the ion transport layer 115, which can facilitate the formation of a flush transition at the overlapping edge position and reduce the risk of stress concentration. The ion transport layer 115 covering a part or the entire surface of the second section 1142 of the active material layer 114 can provide an ion transport channel for the ions in the covered second section 1142, thereby improving ion transport efficiency, ameliorating problems such as battery polarization during charging, and maintaining electrolyte through the micropores, thereby ameliorating the problem of insufficient electrolyte infiltration.

[0132] Figure 7 is a schematic diagram of the ion transport layer located in part of the coiled layer of the electrode tab in some embodiments of the battery cell according to the present disclosure. Figure 8 is a schematic diagram of the ion transport layer located in part of the length range of the curved section in some embodiments of the battery cell according to the present disclosure. Figure 9 is a schematic diagram of the ion transport layer located in the entire length range of the curved section in some embodiments of the battery cell according to the present disclosure. Figures 7-9 In the present embodiment, the range of the ion transport layer in the curved section is indicated by the hatched line. The range of the active material layer is indicated by the part of the planar section 111 and the curved section 112 not filled with the hatched line.

[0133] Reference is made to Figures 7-9 In some embodiments, the ion transport layer 115 is located in at least part of the coiled layer of the electrode tab 11.

[0134] The ion transport layer 115 can be located in part of the coiled layer of the electrode tab 11 as shown in Figure 7 The ion transport layer 115 can be located in part of the coiled layer of the electrode tab 11 as shown in Figure 8 and Figure 9 The ion transport layer 115 can be located in part of the coiled layer of the electrode tab 11 as shown in

[0135] In the embodiment, the ion transport layer 115 can be arranged on the bending section 112 of a part of the winding layers of the pole piece 11 according to actual needs (e.g. stress distribution, etc.), so that the ion transport capacity of the part of the winding layers on which the ion transport layer 115 is arranged can be effectively improved, and more active material layers can be reserved on the bending section to improve the capacity of the electrode assembly. The ion transport layer 115 can be arranged on the bending section 112 of all the winding layers of the pole piece, so that the ion transport capacity of the bending section 112 can be more comprehensively improved from the inside to the outside in the winding structure.

[0136] Reference Figure 7 In some embodiments, the ion transport layer 115 is arranged on the winding layers of the A th to B th winding layers of the pole piece 11, A is less than B, A is greater than or equal to 2 / 5 of N, and less than 3 / 5 of N, B is greater than 2 / 5 of N, and less than or equal to 3 / 5 of N, N is the total number of winding layers of the pole piece 11.

[0137] Here, the A th to B th winding layers refer to a part of the winding layers from the inside to the outside of the winding structure. A, B and N are all positive integers. For example, for a pole piece winding structure with N being 10, the A th to B th winding layers can be the 4 th to 6 th winding layers, the 5 th to 6 th winding layers, or the 4 th to 5 th winding layers.

[0138] Through simulation analysis, it can be found that the positions of the bending section 112 of the pole piece 11 with the maximum stress are concentrated in the range of 2 / 5 to 3 / 5 of the total number of winding layers. Therefore, in the embodiment, the ion transport layer 115 is arranged on the A th to B th winding layers, so that the ion transport capacity of the region with the maximum stress can be effectively improved, the problem of insufficient electrolyte infiltration can be reduced, and more active material layers can be reserved on the bending section to improve the capacity of the electrode assembly.

[0139] Reference Figures 7-9 In some embodiments, the ion transport layer 115 is arranged on at least part of the bending section 112 along the length direction of the pole piece 11.

[0140] The bending section 112 of a part or all of the winding layers can be arranged with the ion transport layer 115 as a whole, as shown in Figure 7 and Figure 9 The bending section 112 of a part or all of the winding layers can be arranged with the ion transport layer 115 as a whole, as shown in Figure 8 and a part of the angle range.

[0141] In the present embodiment, the ion transport layer 115 can be provided on a portion of the curved section 112 according to actual needs (e.g. stress distribution, etc.), so that the portion of the curved section 112 on which the ion transport layer 115 is provided can effectively improve the ion transport capacity, reduce the influence of factors such as stress, and can retain more active material layers in the curved section to improve the capacity of the electrode assembly. Providing the ion transport layer 115 on the entire curved section 112 can more comprehensively improve the ion transport capacity of the curved section 112 throughout the curved section 112.

[0142] Reference Figures 5-9 In some embodiments, the length of the ion transport layer 115 provided in each winding layer of the tab 11 along the length direction of the tab 11 is 1 / 6-1 / 2 of the length of the curved section 112 in the corresponding winding layer.

[0143] For each winding layer of the tab 11, the curved sections 112 on both sides corresponding to the winding layer are approximately equal to an entire ellipse. According to the approximate ellipse circumference formula, the length L of the ion transport layer 115 corresponding to each winding layer of the tab 11 is i satisfies: L i =[2π*b i +4(a i -b i )] / c; where L i is the length of the ion transport layer 115 in the i-th winding layer of the tab 11, a i is the major axis of the curved section 112 of the tab 11 in the i-th winding layer, b i is the minor axis of the curved section 112 of the tab 11 in the i-th winding layer, and c takes a value of 2≤c≤6.

[0144] For each winding layer of the tab 11, the curved section 112 on one side is approximately equal to a half ellipse, where the semi-axis in the direction perpendicular to the flat section 111 is the minor axis, and the semi-axis in the direction parallel to the flat section 111 is the major axis. The sizes of the major axis and the minor axis corresponding to different winding layers are different.

[0145] In the above formula, for the i-th winding layer, the approximate ellipse circumference formula is 2π*b i +4(a i -b i ), and according to the value of c, the circumference of the ellipse can be divided into c parts. For example, Figure 8As shown in FIG. 1, c can be 6, and 1 / 6 of the circumference of the ellipse can be obtained. The curved section 112 can be mirror-symmetrical to the central plane of the flat section in a winding structure, so that 1 / 12 of the circumference of the ellipse is arranged on each side of the central plane. This is basically equivalent to arranging the ion transport layer 115 in the area where the stress of the curved section is the largest, thereby improving the ion transport capacity of the area where the stress is the largest.

[0146] As shown in FIG. 1, c can be 6, and 1 / 6 of the circumference of the ellipse can be obtained. The curved section 112 can be mirror-symmetrical to the central plane of the flat section in a winding structure, so that 1 / 12 of the circumference of the ellipse is arranged on each side of the central plane. This is basically equivalent to arranging the ion transport layer 115 in the area where the stress of the curved section is the largest, thereby improving the ion transport capacity of the area where the stress is the largest. Figure 7 Figure 9 As shown in FIG. 1, c can be 6, and 1 / 6 of the circumference of the ellipse can be obtained. The curved section 112 can be mirror-symmetrical to the central plane of the flat section in a winding structure, so that 1 / 12 of the circumference of the ellipse is arranged on each side of the central plane. This is basically equivalent to arranging the ion transport layer 115 in the area where the stress of the curved section is the largest, thereby improving the ion transport capacity of the area where the stress is the largest.

[0147] For the above formula, c can also be between 2 and 6, such as 2.5, 3, 4, 4.5, 5, 5.5, etc., so as to arrange ion transport layers 115 of different lengths in the curved section 112.

[0148] In the present embodiment, the curved section corresponding to each winding layer includes two curved sections on both sides of the flat section, and the length of the ion transport layer is set to 1 / 6 to 1 / 2 of the length of the curved section corresponding to the winding layer, so that the ion transport layer is arranged in the entire length or part of the length of the curved section, which can effectively balance the ion transport capacity of the corresponding area of the curved section and the improvement of the capacity of the electrode assembly.

[0149] Figure 10 FIG. 1 is a schematic diagram of the ion transport layer covering the active material layer of the curved section in some embodiments of the battery device according to the present disclosure. Without being limited to Figures 7-9 In some embodiments, the ion transport layer 115 covers the surface of the current collector substrate 113 of the curved section 112, as shown in FIG. 1. Figure 10 As shown in FIG. 1, the ion transport layer 115 can cover part of the active material layer 114 or the entire active material layer of the curved section 112.

[0150] The setting range of the ion transport layer 115 in the winding layer of the electrode sheet 11 and along the length direction of the electrode sheet 11 can refer to the previous Figures 7-9 embodiments, which will not be repeated here.

[0151] Figure 11 FIG. 1 is a schematic diagram of the ion transport layer covering the active material layer of the curved section in some embodiments of the battery device according to the present disclosure. Without being limited to Figures 7-11 In some embodiments, the ion transport layer 115 is continuously arranged along the length direction of the electrode sheet 11 or is arranged at intervals along the length direction of the electrode sheet 11 in the curved section 112 of the electrode sheet 11. ​

[0152] As Figures 7-10 For each winding layer of the electrode tab provided with the ion transport layer 115, in the bending section 112 on one side, the ion transport layer 115 is continuously arranged along the length direction of the electrode tab 11. In this way, the part of the bending section 112 where the ion transport layer 115 is continuously arranged can uniformly improve the ion transport capacity, and it is more convenient to prepare and form.

[0153] As Figure 11 shown, the ion transport layer 115 can be arranged in the bending section 112 of the electrode tab 11 along the length direction of the electrode tab 11. In Figure 11 , dr1 is the length direction of the electrode tab, and dr2 is the direction perpendicular to the surface of the electrode tab, which is equivalent to the thickness direction of the electrode tab. By arranging the ion transport layer 115 in the bending section 112 along the length direction of the electrode tab 11, a structure in which the ion transport layer 115 and the active material layer 114 are alternately arranged can be formed. In this way, the active material layer 114 in the bending section 112 can perform ion transport with the aid of the adjacent ion transport layer 115, which can improve the ion transport efficiency while taking into account the improvement of the capacity of the electrode assembly, so as to improve the kinetic performance, effectively reduce the polarization of the battery during charging, and improve the large-rate charging and discharging capacity.

[0154] Referring to Figure 11 In some embodiments, the second section 1142 is arranged in the bending section 112 along the length direction of the electrode tab 11, and the ion transport layer 115 is located between two adjacent second sections 1142.

[0155] The ion transport layer 115 located between two adjacent second sections 1142 can provide an ion transport channel for the active material layer 114 adjacent thereto through the solid-state electrolyte, and can retain a certain amount of electrolyte to reduce the situation of insufficient wetting, thereby more effectively improving the ion transport performance of the bending section 112.

[0156] Referring to Figure 11 In some embodiments, along the length direction of the electrode tab 11, the length L2 of each second section 1142 is 5-10 mm, and the length L1 of the ion transport layer 115 located between two adjacent second sections 1142 is 1-3 mm.

[0157] The length L2 of each second section 1142 can be 5 mm, 7 mm, 8.5 mm, 9 mm, or 10 mm, etc. The length L1 of the ion transport layer 115 located between two adjacent second sections 1142 can be 1 mm, 1.2 mm, 1.8 mm, 2.4 mm, 2.7 mm, or 3 mm, etc.

[0158] In the present embodiment, by setting the length L2 of the second section 1142 to be relatively wide and the length L1 of the ion transport layer 115 to be relatively narrow, the capacity of the electrode assembly can be improved, and the ion transport capacity can be improved by using the ion transport layer 115 adjacent to the active material layer 114, so that the battery cell can obtain better performance.

[0159] Figure 12 and Figure 13 are schematic diagrams of the lateral width distribution of the ion transport layer on the electrode tab in some embodiments of the battery cell according to the present disclosure. Referring to Figure 3 , Figure 12 and Figure 13 , in some embodiments, the battery cell 100 further comprises a housing 21 and an electrolyte, and the electrode assembly 10 and the electrolyte are accommodated in the inner cavity of the housing 21. Along the height direction of the housing 21, the lateral width W1 of the ion transport layer 115 at the position close to the bottom of the housing 21 is less than or equal to the lateral width W2 of the ion transport layer 115 at the position close to the top of the housing 21.

[0160] As shown in Figure 3 , the electrode assembly 10 is arranged in the inner cavity of the housing 21. Along the height direction of the housing 21, one end of the wound structure of the electrode assembly 10 is close to the bottom of the housing 21, and the other end is close to the opening side of the top of the housing 21. In Figure 12 and Figure 13 , dr3 is the height direction of the housing 21, which is perpendicular to the length direction of the wound electrode tab 11, so it is equivalent to the width direction of the electrode tab 11. While the lateral width of the ion transport layer 115 actually refers to the dimension of the ion transport layer 115 along the length direction of the electrode tab 11.

[0161] In Figure 12 , the lateral width W1 can be equal to the lateral width W2, so as to form an ion transport layer 115 with uniform size, which is more convenient for preparation and processing. In Figure 12 , the lateral width W2 is greater than the lateral width W1, so as to form a trapezoidal shape in Figure 12 , but the ion transport layer 115 is not limited to this shape, and can be provided with an arc shape or a stepped shape on both sides, and the change of the lateral width can be linear or phased from bottom to top.

[0162] In the embodiment, considering that the electrolyte is affected by gravity to present a situation of more on the top and less on the bottom in the shell 21, in order to improve the ion transmission effect on the top, by making the lateral width W1 of the ion transmission layer 115 at the position close to the bottom of the shell 21 less than the lateral width W2 of the ion transmission layer 115 at the position close to the top of the shell 21, the solid-state electrolyte close to the top of the shell 21 can be increased to improve the situation that the electrolyte amount on the top is relatively less, so that the ion transmission performance is more uniform in the height direction of the shell 21.

[0163] In addition, referring to Figure 3 , the battery monomer 100 can further include a top cover 22 arranged on the top of the shell 21. The shell 21 can be surrounded by one or more side plates. The shell 21 can be made of a conductive metal material or plastic, and optionally, the shell 21 is made of aluminum or aluminum alloy. The top cover 22 is used to form a sealed cavity with the shell 21 to accommodate the electrode assembly 10. As Figure 3 shown, the first pole 25 and the second pole 26 are arranged on the top cover 22 with an end opening arranged at one end of the shell 21. The first pole 25 is electrically connected to the positive electrode tab 11a of the electrode assembly 10 through the first current collector 23, and the second pole 26 is electrically connected to the negative electrode tab 11b of the electrode assembly 10 through the second current collector 24.

[0164] The top cover 22 can be made of a metal (such as aluminum, aluminum alloy, etc.) or a non-metal material (plastic) with certain hardness and strength. The top cover 22 and the shell 21 can be fixedly connected by welding, bonding or through a connecting piece, etc. Some functional components can be arranged on the top cover 22, such as a liquid injection mechanism, a pressure relief mechanism, etc. As Figure 3 shown, the top cover 22 can be provided with a liquid injection hole 27 and an explosion-proof valve 28.

[0165] The preparation and performance test of the electrode assembly in the embodiment of the disclosure are described below.

[0166] Example 1: referring to Figure 8 , the positive electrode active material layer is arranged at the position of the flat section and the curved section of the positive electrode tab, and the material of the positive electrode active material layer includes: positive electrode active material LiNi 0.8 Co 0.1 Mn 0.1 O2, conductive agent acetylene black and binder PVDF. Referring to Figure 8 , the negative electrode active material layer is arranged at the position of the flat section and the curved section of the negative electrode tab, and the material of the negative electrode active material layer includes: graphite, binder CMC (sodium carboxymethyl cellulose) and conductive agent conductive carbon black mixed in a mass ratio of 95:2:3.

[0167] An ion transport layer is arranged at other positions of the bending section of the positive electrode tab, and the material of the ion transport layer comprises: positive electrode active material LiNi 0.8 Co 0.1 Mn 0.1 O2, polymer electrolyte, conductive agent acetylene black and binder PVDF. An ion transport layer is arranged at other positions of the bending section of the negative electrode tab, and the material of the ion transport layer comprises: graphite, polymer electrolyte, binder CMC and conductive agent conductive carbon black mixed in a mass ratio of 47.5:47.5:2:3.

[0168] The electrolyte is obtained by mixing ethylene carbonate, methyl ethyl carbonate and diethyl carbonate in a volume ratio of 1:1:1, and then dissolving lithium salt LiPF6 in the mixed solvent to prepare an electrolyte with a concentration of 1 mol / L. The separator is a polyethylene film with a thickness of 9 μm, which is cut to an appropriate width before use.

[0169] In the comparative example, the electrolyte, the separator and the coating thickness are consistent with Example 1, and the only difference is that the positive electrode tab is provided with the same positive electrode active material layer as Example 1 at the plane section and the bending section, and the negative electrode tab is provided with the same negative electrode active material layer as Example 1 at the plane section and the bending section.

[0170] The battery cells are prepared according to Example 1 and the comparative example, and the two battery cells are adjusted to 20% SOC using a battery cell test device, and then discharged at 2C. The discharge state of charge (SOC) of the battery cell in the comparative example is 6.8%, and the discharge SOC of the battery cell in Example 1 is 8.1%, which is significantly higher than that of the comparative example.

[0171] Example 2: Reference Figure 10 An ion transport layer is arranged at other positions of the bending section of the positive electrode tab, and the material of the ion transport layer comprises: positive electrode active material LiNi 0.8 Co 0.1 Mn 0.1 O2, conductive agent acetylene black and binder PVDF. Reference Figure 10 An ion transport layer is arranged at other positions of the bending section of the negative electrode tab, and the material of the ion transport layer comprises: graphite, binder and conductive agent mixed in a mass ratio of 95:2:3.

[0172] The surface of the positive active material layer on the curved section of the positive electrode tab is coated with an ion transport layer having a thickness of 15 μm, the material of the ion transport layer comprising: a polymer electrolyte and a binder PVDF mixed in a mass ratio of 93:7. The surface of the negative active material layer on the curved section of the negative electrode tab is coated with an ion transport layer having a thickness of 15 μm, the material of the ion transport layer comprising: a polymer electrolyte and a binder PVDF mixed in a mass ratio of 93:7.

[0173] The electrolyte solution is obtained by mixing ethylene carbonate, methyl ethyl carbonate and diethyl carbonate in a volume ratio of 1:1:1, and then dissolving lithium salt LiPF6 in the mixed solution to obtain an electrolyte solution having a concentration of 1 mol / L. The separator is a polyethylene film having a thickness of 9 μm, which is cut to a suitable width before use.

[0174] In the comparative example, the electrolyte solution, the separator and the coating thickness are the same as in Example 2, and the only difference is that the planar section of the positive electrode tab is provided with the same positive active material layer as in Example 2, and the planar section of the negative electrode tab is provided with the same negative active material layer as in Example 2.

[0175] The battery cells are prepared according to Example 2 and the comparative example, and the two battery cells are adjusted to 20% SOC using a battery cell testing device, and then discharged at 2C. The State of Charge (SOC) of the discharged battery cell obtained by testing the comparative example is 6.8%, and the SOC of the discharged battery cell obtained by testing Example 2 is 7.4%, which is significantly higher than that of the comparative example.

[0176] The above-described embodiments of the battery cell 100 can be applied to various battery devices 30. Therefore, in one aspect of the present disclosure, a battery device 30 is provided, comprising the aforementioned battery cell 100.

[0177] The battery device 30 comprising the battery cell 100 of the aforementioned embodiments can achieve better reliability.

[0178] The above-described embodiments of the battery device 30 can be applied to various electrical equipment. Therefore, in one aspect of the present disclosure, an electrical equipment is provided, comprising the aforementioned battery device 30.

[0179] The electrical equipment comprising the battery device 30 of the aforementioned embodiments can achieve better reliability.

[0180] A specific example of the battery cell of the present disclosure will be described below with reference to Figure 3 , Figure 8 and Figure 12 .

[0181] The battery cell 100 includes a housing 21, an electrode assembly 10, and an electrolyte, the electrode assembly 10 and the electrolyte being accommodated in an inner cavity of the housing 21. The electrode assembly 10 includes a tab 11 and a separator 12, the tab 11 and the separator 12 being alternately stacked and wound into a wound structure. The tab 11 has a planar section 111 and a curved section 112, the tab 11 including a current collector substrate 113, an active material layer 114 provided on at least a portion of the current collector substrate 113 located at the planar section 111, and an ion transport layer 115 provided on a portion of the current collector substrate 113 located at the curved section 112, the ion transport layer 115 including a solid-state electrolyte and an active material. The D50 of the powder particles of the solid-state electrolyte is 220-280 nm. The surface of the ion transport layer 115 is flush with the surface of the portion of the active material layer 114 not covered by the ion transport layer 115.

[0182] The ion transport layer 115 is located at all the wound layers of the tab 11, and in each wound layer, the ion transport layer 115 is continuously provided on the portion of the tab 11 located at the curved section 112 in the length direction of the tab 11. The thickness of the ion transport layer 115 covering a portion of the surface of the portion of the current collector substrate 113 located at the curved section 112 is equal to the thickness of the second section 1142 and the first section 1141 of the active material layer 114. In the height direction of the housing 21, the lateral width W1 of the ion transport layer 115 at a position close to the bottom of the housing 21 is equal to the lateral width W2 of the ion transport layer 115 at a position close to the top of the housing 21.

[0183] So far, the embodiments of the present disclosure have been described in detail. In order to avoid obscuring the concept of the present disclosure, some details known in the art are not described. Those skilled in the art can fully understand how to implement the technical solutions disclosed herein according to the above description.

[0184] Although some specific embodiments of the present disclosure have been described in detail through examples, those skilled in the art should understand that the above examples are only for illustration, not for limiting the scope of the present disclosure. Those skilled in the art should understand that the above embodiments can be modified or some technical features can be replaced equivalently without departing from the scope and spirit of the present disclosure. The scope of the present disclosure is defined by the appended claims.

Claims

1. A battery cell (100) characterized by, The electrode assembly (10) comprises a tab (11) and a separator (12), which are alternately stacked and wound into a winding structure; the tab (11) has a planar section (111) and a curved section (112), and comprises a current collector substrate (113), an active material layer (114) and an ion transport layer (115); the active material layer (114) is arranged on the current collector substrate (113) at least on the planar section (111), and the ion transport layer (115) is arranged on the current collector substrate (113) at least on the curved section (112), and the ion transport layer (115) comprises a solid-state electrolyte. The surface of the ion transport layer (115) is flush with the surface of the part of the active material layer (114) not covered by the ion transport layer (115).

2. The battery cell (100) according to claim 1, characterized in that The ion transport layer (115) is arranged on at least part of the winding layers of the tab (11).

3. The battery cell (100) according to claim 2, characterized in that The winding layers of the tab (11) on which the ion transport layer (115) is arranged are the A th to B th winding layers of the tab (11), A is less than B, A is greater than or equal to 2 / 5 of N, and less than 3 / 5 of N, B is greater than 2 / 5 of N, and less than or equal to 3 / 5 of N, N is the total number of winding layers of the tab (11).

4. The battery cell (100) of claim 1, wherein, Along the length direction of the tab (11), the ion transport layer (115) is arranged on at least part of the curved section (112).

5. The battery cell (100) according to claim 4, characterized in that Along the length direction of the tab (11), the length of the ion transport layer (115) arranged in each winding layer of the tab (11) is 1 / 6-1 / 2 of the length of the curved section (112) in the corresponding winding layer.

6. The battery cell (100) of claim 1, wherein, The ion transport layer (115) is continuously arranged along the length direction of the tab (11) on the curved section (112) of the tab (11), or is arranged at intervals along the length direction of the tab (11) on the curved section (112) of the tab (11).

7. The battery cell (100) according to claim 1, characterized in that The active material layer (114) comprises: a first section (1141) covering at least part of the surface of the part of the current collector substrate (113) located on the planar section (111); and a second section (1142) covering at least part of the surface of the part of the current collector substrate (113) located on the curved section (112); The ion transport layer (115) covers at least part of the surface of the part of the current collector substrate (113) located on the curved section (112) and / or at least part of the surface of the second section (1142).

8. The battery cell (100) according to claim 7, characterized in that The thickness of the ion transport layer (115) covering at least part of the surface of the part of the current collector substrate (113) located on the curved section (112) is equal to the thickness of the second section (1142) and the first section (1141).

9. The battery cell (100) according to claim 7, characterized in that The sum of the thickness of the ion transport layer (115) covering at least part of the surface of the second section (1142) and the thickness of the second section (1142) covered by the ion transport layer (115) is equal to the thickness of the first section (1141).

10. The battery cell (100) of claim 7, wherein, The second segments (1142) are arranged at intervals along the length direction of the pole piece (11), and the ion transport layer (115) is located between two adjacent second segments (1142).

11. The battery cell (100) according to claim 10, characterized in that The length L2 of each second segment (1142) is 5-10 mm, and the length L1 of the ion transport layer (115) between two adjacent second segments (1142) is 1-3 mm.

12. The battery cell (100) of claim 1, wherein, The ion transport layer (115) further comprises a binder.

13. The battery cell (100) of claim 1, wherein, The ion transport layer (115) further comprises an active material.

14. The battery cell (100) of claim 1, wherein, The D50 of the powder particles of the solid-state electrolyte is 220-280 nm.

15. The battery cell (100) of claim 1, wherein, The electrode assembly (10) and an electrolyte are contained in an inner cavity of the shell (21). The lateral width W1 of the ion transport layer (115) at a position close to the bottom of the shell (21) is less than or equal to the lateral width W2 of the ion transport layer (115) at a position close to the top of the shell (21) along the height direction of the shell (21).

16. A battery device (30) characterized by The battery cell (100) according to any one of claims 1-15. The battery device (30) according to claim 16.

17. An electrical device, characterized by The battery device (30) according to claim 16. ​

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