Electrode assembly, battery cell, battery and electric device

Abstract

The utility model relates to an electrode assembly, a battery monomer, a battery and a power utilization device. The electrode assembly comprises a plurality of roll cores and an elastic slow release part, each roll core comprises a first side plane and a second side plane which are connected in an intersecting mode, and all the roll cores are arranged around a preset axis in an end-to-end connection mode. And in every two adjacent roll cores, the first side plane of one roll core is opposite to the second side plane a2 of the other roll core. The elastic slow-release piece is elastically connected between the first side plane and the second side plane which are oppositely arranged, the elastic slow-release piece is provided with a containing part for containing the electrolyte, and the electrolyte contained in the containing part can be released when the elastic slow-release piece is pressed to deform. According to the technical scheme, the barren solution condition and the electrode piece interface contact condition of the electrode assembly can be improved, and the cycle capacity of the battery is improved.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and in particular to electrode assemblies, battery cells, batteries and electrical devices. Background Art

[0002] The electrode assembly is an important part of the battery cell and is the smallest unit for electrochemical reactions. For wound electrode assemblies, cylindrical winding and square flat winding are common. Both winding methods result in a long curved contact interface between the layers of the core. The curved contact interface is prone to contact mismatch, local electrode sheet accumulation or stretching after bending, etc., which is not conducive to battery cycle performance. In addition, the electrode sheet expands during the charge and discharge process of the electrode assembly, which will squeeze out the electrolyte in the electrode assembly, reduce the electrolyte retention of the electrode assembly, and cause the electrode assembly to be poorly liquid, which can easily cause the battery cycle to dive and reduce the battery cycle performance. Utility Model Content

[0003] Based on this, the present application provides an electrode assembly, a battery cell, a battery and an electrical device to improve the battery cycle performance.

[0004] In a first aspect, an embodiment of the present application provides an electrode assembly, comprising:

[0005] A plurality of winding cores, each of the winding cores comprising a first side plane and a second side plane intersecting and connected; all the winding cores are arranged around a preset axis, and the angle between the first side plane and the second side plane in each of the winding cores faces the preset axis; in every two adjacent winding cores, the first side plane of one of the winding cores is arranged opposite to the second side plane of the other of the winding cores;

[0006] An elastic slow-release member is elastically connected between the first side plane and the second side plane which are arranged opposite to each other; the elastic slow-release member has a receiving portion for receiving electrolyte, and can release the electrolyte received in the receiving portion when deformed by pressure.

[0007] In some embodiments, the receiving portion includes a microporous structure formed in the elastic slow-release member;

[0008] And / or, the elastic slow-release member includes an elastic liquid sac, the inner space of the elastic liquid sac forms the accommodating portion, and a hole portion communicating with the inner space is formed on the elastic liquid sac.

[0009] In some embodiments, the elastic sustained-release member includes an elastic gel formed with the microporous structure.

[0010] In some embodiments, the cross-section of each of the winding cores is fan-shaped or polygonal.

[0011] In some embodiments, each of the winding cores also includes a third side plane, and the first side plane, the second side plane and the third side plane are connected end to end in sequence; the angle between the first side plane and the second side plane is a first angle, and the sum of the first angles of all the winding cores is equal to 360°.

[0012] In some embodiments, the number of the winding cores is 6, and all of the winding cores surround the preset axis to form a hexagonal prism structure.

[0013] In some embodiments, the size of the multiple winding cores on the preset axis is L, and the cross-sectional area of ​​the multiple winding cores perpendicular to the preset axis is S, satisfying: 20.8≤S / L≤38.

[0014] In some embodiments, a dimension L of each of the winding cores on the preset axis satisfies: 1200 mm ≥ L ≥ 280 mm.

[0015] In some embodiments, each of the winding cores includes a positive electrode tab and a negative electrode tab, the positive electrode tabs of all the winding cores are arranged at the same end of the electrode assembly on the preset axis, and the negative electrode tabs of all the winding cores are arranged at the same other end of the electrode assembly on the preset axis.

[0016] In some embodiments, the electrode assembly further comprises an insulating tape, wherein the insulating tape binds the entire winding core.

[0017] In a second aspect, an embodiment of the present application provides a battery cell, including:

[0018] Battery housing;

[0019] And the electrode assembly described in any of the above embodiments, wherein the electrode assembly is accommodated in the battery casing.

[0020] In a third aspect, an embodiment of the present application provides a battery, characterized in that it includes the above-mentioned battery cell.

[0021] In a fourth aspect, an embodiment of the present application provides an electrical device, comprising the above-mentioned battery, wherein the battery is used to provide electrical energy.

[0022] In the above-mentioned electrode assembly, battery cell, battery and electrical device, the internal layer structure of each winding core is in planar contact at the first side plane and the second side plane, and the interface contact of each layer is good, which helps to improve the battery cycle capacity. Moreover, when the pole piece inside the winding core expands and the first side plane and the second side plane squeeze the elastic slow-release member outward, the elastic slow-release member deforms with the expansion of the winding core, so that the electrolyte in its accommodating part is squeezed out and the electrolyte is replenished to the winding core, which can reduce the liquid starvation degree of the winding core and improve the battery cycle capacity. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present application. Moreover, the same reference numerals are used throughout the drawings to represent the same components. In the drawings:

[0024] Figure 1 This is a schematic diagram of the structure of the electrode assembly of some embodiments of the present application.

[0025] Figure 2 Schematic top view of electrode assemblies according to some embodiments of the present application.

[0026] Figure 3 This is a schematic diagram of the structure of the elastic release component of some embodiments of the present application.

[0027] Figure 4 This is a schematic diagram of the structure of the winding core of some embodiments of the present application.

[0028] Figure 5 This is a schematic diagram of the structure of a battery cell according to some embodiments of the present application.

[0029] Figure 6 for Figure 5 An exploded schematic diagram of a battery cell is shown.

[0030] The reference numerals in the specific implementation manner are as follows:

[0031] 100, battery cell; 10, electrode assembly; F, preset axis; 11, winding core; 11a, lateral outer surface; a1, first side plane; a2, second side plane; a3, third side plane; 11b, end face; 12, elastic release member; 12c, accommodating portion; c1, microporous structure; α, first angle; 13, insulating tape; 20, battery case; 21, side shell; 22, end cover; 23, bottom cover; 30, positive electrode collector plate; 40, negative electrode collector plate. DETAILED DESCRIPTION

[0032] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present application, so the present application is not limited by the specific embodiments disclosed below.

[0033] In the description of the present application, it should be understood that terms such as “center”, “longitudinal”, “lateral”, “length”, “width”, “thickness”, “up”, “down”, “front”, “back”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inside”, “outside”, “clockwise”, “counterclockwise”, “axial”, “radial”, “circumferential”, etc., indicating orientations or positional relationships, if any, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0034] In addition, if present, the terms "first" and "second" are used for descriptive purposes only and are not to be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of this application, "plurality" means at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0035] In this application, unless otherwise clearly specified and limited, if any, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0036] In the present application, if it appears, unless otherwise clearly specified and limited, a first feature “above” or “below” a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature “above”, “above” and “above” a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature “below”, “below” and “below” a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0037] It should be noted that, if present, when an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used herein are for illustrative purposes only and are not intended to be the only implementation method.

[0038] In order to solve the problem of poor battery cycle performance caused by poor interface contact between layers of the core and poor liquid, the embodiment of the present application proposes an electrode assembly. The electrode assembly includes a core wound to form at least two intersecting side planes, and the internal layers of the core can be wound along the plane. The internal layers of the core have good interface contact, which helps to improve the battery cycle performance. In addition, multiple cores are connected end to end around a preset axis, and an elastic release member is provided between the side planes between two adjacent cores. The elasticity of the elastic release member is used to connect the adjacent cores to allow each core to expand. When the core expands, the electrolyte contained in the elastic release member can be squeezed out and replenished into the core, reducing the degree of liquid deficiency in the core and further improving the battery cycle performance.

[0039] The electrode assembly provided in the embodiment of the present application is assembled in the battery housing to form a battery cell. In addition to the battery housing and the electrode assembly contained in the battery housing, the battery cell may also include an electrolyte injected into the battery housing, an insulating film wrapped around the electrode assembly, etc. The battery cell may be a secondary battery or a primary battery, and the battery cell may be a lithium-sulfur battery, a sodium-ion battery, or a magnesium-ion battery, but is not limited thereto. The battery cell may be cylindrical, flat, rectangular, or in other shapes.

[0040] A battery can be prepared using the battery cells in the embodiments of the present application. In addition to the battery cells, the battery may also generally include a housing, in which the battery cells are housed. The housing may accommodate a plurality of battery cells. The plurality of battery cells may be connected in series, in parallel, or in mixed connection, wherein mixed connection means that the plurality of battery cells are both connected in series and in parallel. The battery may also include other structures, for example, the battery may also include a busbar component for realizing electrical connection between the plurality of battery cells.

[0041] The battery provided in the embodiment of the present application can be applied to an electrical device to provide electrical energy for the electrical device. The electrical device can be, but is not limited to, a mobile phone, a tablet, a laptop computer, an electric toy, an electric tool, a battery car, an electric car, a ship, etc. Taking the electrical device as a vehicle as an example, the battery can be set at the rear, front or bottom of the vehicle, and the battery can provide electrical energy for the drive of the vehicle, and can also provide electrical energy for the control system of the vehicle.

[0042] The electrode assembly provided in the embodiments of the present application is described in detail below.

[0043] Please refer to Figure 1 , Figure 2 and Figure 3 The electrode assembly 10 provided in the embodiment of the present application includes a plurality of winding cores 11 and an elastic release member 12. Each winding core 11 includes a first side plane a1 and a second side plane a2 that are intersecting and connected, and all the winding cores 11 are arranged around a preset axis F, and the angles between the first side plane a1 and the second side plane a2 in each winding core 11 face the preset axis F. In each two adjacent winding cores 11, the first side plane a1 of one of the winding cores 11 is arranged opposite to the second side plane a2 of the other winding core 11. The elastic release member 12 is elastically connected between the first side plane a1 and the second side plane a2 that are arranged opposite to each other, and the elastic release member 12 has a accommodating portion 12c for accommodating an electrolyte, and can release the electrolyte accommodated in the accommodating portion 12c when deformed under pressure.

[0044] The core 11 is a bare battery cell obtained by winding the positive electrode sheet, the separator, and the negative electrode sheet after being stacked. The core 11 has a lateral outer surface 11a arranged along its winding direction, and the lateral outer surface 11a includes at least two side planes. Specifically, the lateral outer surface 11a includes a first side plane a1 and a second side plane a2, and the first side plane a1 and the second side plane a2 are both planar, adjacent to each other and intersecting. When arranged, in each core 11, the angle formed by the first side plane a1 and the second side plane a2 is set toward the preset axis.

[0045] Usually, the number of the winding cores 11 is not less than 3, and the plurality of winding cores 11 are arranged around the preset axis F. Of course, the number of the winding cores 11 can also be two, for example, one of the winding cores 11 is a small sector column with a smaller central angle, and the other winding core 11 is a large sector column with a larger central angle.

[0046] The preset axis F corresponds to the width direction of the electrode sheet in each winding core 11. Generally, but not limited to, the shapes of the winding cores 11 are substantially the same, and the multiple winding cores 11 are connected end to end around the preset axis F, so that the electrode assembly 10 can form an axisymmetric structure relative to the preset axis F.

[0047] In every two adjacent winding cores 11, the first side plane a1 of one winding core 11 is arranged opposite to the second side plane a2 of the other winding core 11, and an elastic slow-release member 12 is arranged between the two. The elastic slow-release member 12 can be elastically deformed in the relative direction of the first side plane a1 and the second side plane a2, so as to deform along with the expansion of the winding core 11 without interfering with the normal charging and discharging of the winding core 11.

[0048] The elastic slow-release member 12 may be clamped between the first side plane a1 and the second side plane a2, or may be connected to the first side plane a1 and the second side plane a2 by bonding or the like. The elastic slow-release member 12 may be distributed throughout the space between the first side plane a1 and the second side plane a2, or may be arranged in a local position of the space, for example, the elastic slow-release member 12 may be arranged in the middle of the winding core 11 in the space.

[0049] The elastic slow-release member 12 may be arranged between the first side plane a1 and the second side plane a2, or may be arranged on other side peripheral outer surface 11a of the winding core 11. The specific arrangement of the elastic slow-release member 12 is not limited, as long as it is arranged at least between the first side plane a1 and the second side plane a2.

[0050] The elastic slow-release member 12 has a receiving portion 12c capable of accommodating an electrolyte. In some examples, the receiving portion 12c includes micropores, and the micropores can retain the electrolyte inside by capillary action, thereby achieving the accommodation and absorption of the electrolyte. When the elastic slow-release member 12 is squeezed, the electrolyte stored in the micropores is squeezed out, so that the electrolyte can be replenished to the area of ​​the winding core 11 around the elastic slow-release member 12. In other examples, the elastic slow-release member 12 includes an elastic liquid capsule, and the space inside the elastic liquid capsule is the receiving portion 12c capable of accommodating an electrolyte, and a hole portion connecting the space inside the capsule is formed on the elastic liquid capsule. The effect of the hydraulic pressure difference inside and outside the capsule can allow the electrolyte from the outside to enter the capsule through the hole portion. When the hydraulic pressure difference inside and outside the capsule is balanced, the electrolyte is retained in the receiving portion 12c formed in the space inside the capsule. When the elastic liquid capsule is squeezed, the electrolyte in the capsule can be released to the outside of the elastic liquid capsule through the hole portion. The specific structure of the elastic slow-release member 12 is not limited to the above-mentioned method, as long as it can be elastically deformed and can store and release electrolyte.

[0051] In some application scenarios, after the electrode assembly 10 and the battery housing 20 are assembled to form a battery cell 100, the electrolyte is injected into the battery cell 100 through the injection hole on the battery housing 20, and the elastic slow-release member 12 can automatically absorb and retain part of the electrolyte. When the winding core 11 expands and squeezes the elastic slow-release member 12, the elastic slow-release member 12 releases the electrolyte. Of course, the electrolyte can also be filled into the elastic slow-release member 12 in advance before assembling the battery cell 100.

[0052] In the electrode assembly 10, the internal layer structure of each winding core 11 is in planar contact at the first side plane a1 and the second side plane a2, and the interface contact of each layer is good, which helps to improve the battery cycle capacity. When the pole piece inside the winding core 11 expands, the first side plane a1 and the second side plane a2 squeeze the elastic slow-release member 12 outward, and the elastic slow-release member 12 is deformed as the winding core 11 expands, so that the electrolyte in its accommodating portion 12c is squeezed out and the electrolyte is replenished to the winding core 11, which helps to reduce the degree of liquid deficiency of the winding core 11 and further improve the battery cycle capacity.

[0053] In some embodiments, reference Figure 3 The accommodating portion 12 c includes a microporous structure c1 formed in the elastic release-slowing member 12 .

[0054] That is, as described above, the elastic slow-release member 12 can absorb and release electrolyte through micropores. For example, the elastic slow-release member 12 is rubber, silicone, etc. having a micropore structure c1 inside.

[0055] At this time, the elastic slow-release member 12 can not only deform elastically, but also automatically absorb and release the electrolyte, and has a simple structure.

[0056] In some embodiments, the elastic sustained-release element 12 includes an elastic gel having a microporous structure c1.

[0057] Gel refers to a dispersion system in which colloidal particles or polymers in a solution are interconnected under certain conditions to form a spatial network structure, and the gaps in the structure are filled with a liquid as a dispersion medium. Elastic gel refers to a gel structure that significantly shrinks in volume after losing the dispersion medium, and expands again when the dispersion medium is reabsorbed. The elastic slow-release member 12 can be partially formed by the elastic gel, or the entire elastic slow-release member 12 can be formed by the elastic gel.

[0058] The elastic gel can be made of SEBS material. SEBS (Styrene-Ethylene-Butylene-Styrene) is a thermoplastic elastomer made of copolymers of styrene, ethylene and butene. It has good heat resistance, chemical resistance and weather resistance, as well as good elasticity and flexibility. The preparation method of the elastic gel of SEBS material can be: melt SEBS at high temperature, allow SEBS to fully dissolve with liquid oil, and cool to form a jelly-like colloid, and then remove the oil dissolved inside by washing to obtain an elastic gel with a microporous structure c1. Of course, the elastic gel piece can also be made of other materials such as gelatin.

[0059] At this time, an elastic gel member is used as the elastic slow-release member 12, which has better elasticity and electrolyte retention capacity, can also withstand the internal environment of the battery, is easy to produce and prepare, and helps to increase the service life of the battery.

[0060] In some embodiments, the cross-section of each winding core 11 is fan-shaped or polygonal.

[0061] The cross section of the winding core 11 refers to the cross section perpendicular to the preset axis F. The cross section of the winding core 11 may be fan-shaped or polygonal, and generally all the cross sections of the winding cores 11 have the same shape, for example, all are fan-shaped or all are polygons with the same number of sides.

[0062] The cross-section of the winding core 11 can be fan-shaped, and its lateral outer surface 11a includes a first side plane a1, a second side plane a2 and an arc surface, which are connected end to end. Multiple winding cores 11 with fan-shaped cross-sections can be combined to form a cylindrical electrode assembly 10, and the outer shell of a conventional cylindrical electrode assembly can be used.

[0063] The cross section of the winding core 11 can be a polygon such as a triangle, a quadrilateral, a pentagon, or a hexagon. The lateral outer surface 11a of the winding core 11 includes at least three side planes. The internal layer structures of the winding core 11 are in plane contact, and the layer interfaces are better bonded.

[0064] In actual application, when the cross-section of the core 11 is a fan-shaped, triangular, quadrilateral, pentagonal, hexagonal or even other polygons with more sides, the two adjacent connected side planes in each core 11 can be used as the first side plane a1 and the second side plane a2 respectively, and the tip position of the angle formed by the first side plane a1 and the second side plane a2 in each core 11 is set toward the same preset axis F, and the tip positions of each core 11 are arranged around the preset axis F, and then an elastic release member 12 is set between adjacent cores 11 to obtain the electrode assembly 10.

[0065] In some embodiments, reference Figure 2 and Figure 4 Each winding core 11 also includes a third side plane a3, and the first side plane a1, the second side plane a2 and the third side plane a3 are connected end to end in sequence; the angle between the first side plane a1 and the second side plane a2 is a first angle α, and the sum of the first angles α of all the winding cores 11 is 360 degrees.

[0066] That is, the cross section of the winding core 11 is roughly triangular, and the winding core 11 is roughly triangular prism-shaped. The first side plane a1, the second side plane a2, and the third side plane a3 are connected end to end, which means that one end of the first side plane a1 intersects with one end of the second side plane a2, and the other end of the first side plane a1 and the other end of the second side plane a2 intersect with the two ends of the third side plane a3.

[0067] Generally, the first angle α of each winding core 11 is the same, and the sum of the first angles α of the plurality of winding cores 11 is 360°, and the number of the winding cores 11 is equal to 360° divided by the first angle α. Figure 1 In the illustrated embodiment, the number of the winding cores 11 is 6, the first angle α of each winding core 11 is 60°, and the widths of the first side plane a1, the second side plane a2 and the third side plane a3 of the winding core 11 are substantially the same.

[0068] At this time, the electrode assembly 10 is formed by assembling a plurality of triangular prism-shaped winding cores 11 around a preset axis F. The side peripheral outer surface 11a of the triangular prism-shaped winding core 11 is substantially flat, which can make the interface contact of each layer structure inside the winding core 11 better.

[0069] The first side plane a1 and the second side plane a2 may be transitioned by an arc surface, the second side plane a2 and the third side plane a3 may be transitioned by an arc surface, and the first side plane a1 and the third side plane a3 may be transitioned by an arc surface.

[0070] In some embodiments, reference Figure 1 and Figure 2 , the number of winding cores 11 is 6, and all winding cores 11 are formed into a hexagonal column structure around the preset axis F. That is, 6 triangular column-shaped winding cores 11 are formed into a hexagonal column structure around the preset axis F, so as to obtain a hexagonal column-shaped electrode assembly 10.

[0071] In actual application, a hexagonal battery cell 100 can be prepared by using the hexagonal electrode assembly 10. Usually, a battery is formed by a plurality of battery cells 100 in a module. At this time, the hexagonal battery cell 100 can be aligned with other battery cells 100 on all sides, so that the battery cells 100 inside the battery can be closely arranged, effectively utilizing the internal space of the battery and improving the energy density of the battery. Moreover, the sides of the shell of the hexagonal battery cell 100 are connected at an obtuse angle, with a small degree of curvature. When the shell is formed, the stress concentration at the corners is weak, which helps to improve the shell forming yield.

[0072] In some embodiments, in combination Figure 1 The size of the multiple winding cores 11 on the preset axis F is L, and the cross-sectional area of ​​the multiple winding cores 11 perpendicular to the preset axis F is S, satisfying: 20.8≤S / L≤38.

[0073] It is understandable that the cross-sectional shape and area of ​​the multiple cores 11 as a whole are evenly arranged along the preset axis F, that is, the cross-sectional area S of the multiple cores 11 is equal. It should be noted that the cross-sectional area S of all the cores 11 is equal to the sum of the cross-sectional areas of each core 11.

[0074] Specifically, S / L can be selected as 20.8, 21, 25, 28, 30, 32, 35, 36, 38, and values ​​between any adjacent selected values.

[0075] When the value of S / L is not less than 20.8, the size of the electrode assembly 10 on the preset axis F is relatively large. In practical applications, the electrode assembly 10 can be used to prepare a blade-shaped battery cell 100 (commonly known as a blade battery cell) with a relatively large length. The blade battery cell has a relatively large energy density and can be placed horizontally for use (i.e., the preset axis F is arranged horizontally), which is suitable for places with limited height layout space. In addition, since the electrode assembly 10 is formed by a plurality of winding cores 11 tightly arranged around the preset axis F, the heat dissipation of the electrode assembly 10 is mainly carried out through its two end surfaces on the preset axis F. If the size of the electrode assembly 10 on the preset axis F is too long, the heat dissipation effect of the middle area of ​​the electrode assembly 10 is poor. Setting the value of S / L to no more than 38 can take into account the heat dissipation effect of the middle area of ​​the electrode assembly 10 and improve the reliability of the battery.

[0076] In some embodiments, the dimension L of each winding core 11 on the preset axis F satisfies: 1200 mm ≥ L ≥ 280 mm. Specifically, L can be selected as 300 mm, 400 mm, 500 mm, 600 mm, 700 mm, 800 mm, 900 mm, 1000 mm, 1100 mm, 1200 mm, and values ​​between any two adjacent selected values.

[0077] In the embodiment of the present application, the electrode assembly 10 is composed of a plurality of winding cores 11, and each winding core 11 can release electrolyte to its first side plane a1 and second side plane a2 through an elastic release member 12 to improve the electrolyte infiltration effect on the winding core 11. Compared with the electrode assembly 10 formed by a large wound bare cell, the first side plane a1 and the second side plane a2 of each winding core 11 are equivalent to increasing the surface area of ​​the winding core 11 exposed to the electrolyte, which helps to improve the cycle performance of the winding core 11. Even if the electrode assembly 10 has a higher size, it can also have better performance and is suitable for the preparation of high-size batteries.

[0078] Understandably, if Figure 1 As shown, the winding core 11 includes an end surface 11b, which is the outer surface of the winding core 11 located on the preset axis F. The end surface 11b is arranged at both ends of the side peripheral outer surface 11a, and the winding core 11 has a positive electrode ear and a negative electrode ear arranged on the end surface 11b. The battery cell 100 is provided with a positive electrode column and a negative electrode column. The positive electrode ear is used for conductive connection with the positive electrode column, and the negative electrode ear is used for conductive connection with the negative electrode column. Each winding core 11 is connected to an external circuit through the positive electrode ear and the negative electrode ear.

[0079] In some embodiments, each winding core 11 includes a positive electrode tab and a negative electrode tab, the positive electrode tabs of all winding cores 11 are arranged at the same end of the electrode assembly 10 on the preset axis F, and the negative electrode tabs of all winding cores 11 are arranged at the same other end of the electrode assembly 10 on the preset axis F.

[0080] That is, the positive electrode tab and the negative electrode tab of each winding core 11 are arranged at different ends of a preset axis F of the winding core 11 , and the electrode tabs with the same polarity of each winding core 11 are arranged at the same end of the electrode assembly 10 .

[0081] In this way, when the electrode assembly 10 is used to assemble the battery cell 100, the positive electrode collector plate 30 connecting the positive electrode ear and the positive electrode column and the negative electrode collector plate 40 connecting the negative electrode ear and the negative electrode column can be arranged on both sides of the electrode assembly 10. The welding of the positive electrode collector plate 30 and the positive electrode ear and the welding of the negative electrode collector plate 40 and the negative electrode ear are more convenient to operate, which helps to speed up the assembly process of the battery cell 100.

[0082] Of course, the present application does not exclude the feasibility of arranging the positive electrode tab and the negative electrode tab of each winding core 11 at the same end.

[0083] In some embodiments, reference Figure 1 The electrode assembly 10 further includes an insulating tape 13 , which binds the entire winding core 11 .

[0084] The insulating tape 13 may be a polypropylene tape, a polyester tape, a polyimide tape, etc. All the winding cores 11 are formed as a whole, and the insulating tape 13 is wound around the periphery of the whole to bind all the battery cells together.

[0085] At this time, the insulating tape 13 can be used to bind and position each winding core 11, and at the same time, the winding core 11 and the battery outer shell can be electrically isolated to reduce the risk of leakage of the battery shell.

[0086] Typically, the insulating tape 13 is disposed on a portion of the electrode assembly 10 to increase the exposed surface area of ​​the electrode assembly 10 and improve the contact area between the electrode assembly 10 and the electrolyte. Figure 1 In the illustrated embodiment, the insulating tape 13 is arranged at both ends of the electrode assembly 10 to bind both ends of all the winding cores 11 .

[0087] In a specific embodiment of the present application, the electrode assembly 10 includes six winding cores 11, each of which has a triangular cross-section. The six winding cores 11 are assembled around a preset axis F to form a hexagonal electrode assembly 10, and an elastic slow-release member 12 is disposed between each adjacent winding core 11.

[0088] In addition, refer to Figure 5 and Figure 6 The embodiment of the present application further provides a battery cell 100, comprising a battery housing 20 and an electrode assembly 10 in any of the above embodiments, wherein the electrode assembly 10 is accommodated in the battery housing 20. The battery cell 100 includes all the above beneficial effects.

[0089] The battery housing 20 may be an aluminum housing, a steel housing, etc., but is not limited thereto. Figure 6It is understood that the battery housing 20 includes an end cover 22, a side shell 21 and a bottom cover 23. The side shell 21 encloses a receiving cavity with two ends open on a preset axis F. The end cover 22 and the bottom cover 23 are respectively covered at the two ends of the side shell 21, and the electrode assembly 10 is arranged in the receiving cavity. The positive pole ears of all the winding cores 11 are arranged at the same end, and the negative pole ears of all the winding cores 11 are arranged at the same other end. The battery cell 100 also includes a positive current collector 30 and a negative current collector 40. The positive current collector 30 can be connected between the positive pole ear of the electrode assembly 10 and the positive pole column of the end cover 22 by welding or the like, and the negative current collector 40 can be connected between the negative pole ear of the electrode assembly 10 and the negative pole column of the bottom cover 23 by welding or the like. In addition, the positive current collector 30 and the negative current collector 40 can also be connected to the inner wall of the side shell 21 by welding or the like.

[0090] In addition, the embodiment of the present application further provides a battery, comprising the above-mentioned battery cell 100. In some examples, the battery may further include a box body, and the battery cell 100 is accommodated in the box body.

[0091] In addition, an embodiment of the present application further provides an electrical device, comprising the above-mentioned battery, and the battery is used to provide electrical energy.

[0092] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0093] The above-mentioned embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the present application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the attached claims.

Claims

1. An electrode assembly (10), characterized in that: include: A plurality of winding cores (11), each of the winding cores (11) comprising a first side plane (a1) and a second side plane (a2) intersecting and connected; all the winding cores (11) are arranged around a preset axis (F), and the angle between the first side plane (a1) and the second side plane (a2) in each of the winding cores (11) faces the preset axis (F); in every two adjacent winding cores (11), the first side plane (a1) of one of the winding cores (11) is arranged opposite to the second side plane (a2) of the other of the winding cores (11); An elastic slow-release member (12) is elastically connected between the first side plane (a1) and the second side plane (a2) which are arranged opposite to each other; the elastic slow-release member (12) has a receiving portion (12c) for receiving electrolyte, and is capable of releasing the electrolyte received in the receiving portion (12c) when deformed under pressure.

2. The electrode assembly (10) according to claim 1, characterized in that: The accommodating portion (12c) comprises a microporous structure (c1) formed on the elastic slow-release member (12); And / or, the elastic slow-release member (12) comprises an elastic liquid sac, the space inside the elastic liquid sac forms the accommodating portion (12c), and a hole portion communicating with the space inside the sac is formed on the elastic liquid sac.

3. The electrode assembly (10) according to claim 2, characterized in that: The elastic slow-release member (12) comprises an elastic gel formed with the microporous structure (c1).

4. The electrode assembly (10) according to claim 1, characterized in that: The cross-section of each winding core (11) is fan-shaped or polygonal.

5. The electrode assembly (10) according to claim 1, characterized in that: Each of the winding cores (11) further comprises a third side plane (a3), wherein the first side plane (a1), the second side plane (a2) and the third side plane (a3) ​​are connected end to end in sequence; an angle between the first side plane (a1) and the second side plane (a2) is a first angle (α), and the sum of the first angles (α) of all the winding cores (11) is equal to 360°.

6. The electrode assembly (10) according to claim 5, characterized in that: The number of the winding cores (11) is 6, and all the winding cores (11) surround the preset axis (F) to form a hexagonal column structure.

7. The electrode assembly (10) according to claim 1, characterized in that: The size of the multiple winding cores (11) on the preset axis (F) is L, and the cross-sectional area of ​​the multiple winding cores (11) perpendicular to the preset axis (F) is S, satisfying: 20.8≤S / L≤38.

8. The electrode assembly (10) according to claim 1, characterized in that: The dimension L of each winding core (11) on the preset axis (F) satisfies: 1200mm≥L≥280mm.

9. The electrode assembly (10) according to claim 1, characterized in that: Each of the winding cores (11) comprises a positive electrode tab and a negative electrode tab, the positive electrode tabs of all the winding cores (11) are arranged at the same end of the electrode assembly (10) on the preset axis (F), and the negative electrode tabs of all the winding cores (11) are arranged at the same other end of the electrode assembly (10) on the preset axis (F); And / or, the electrode assembly (10) further comprises an insulating tape (13), wherein the insulating tape (13) binds all of the winding cores (11).

10. A battery cell (100), characterized in that: include: A battery housing (20); And the electrode assembly (10) according to any one of claims 1 to 9, wherein the electrode assembly (10) is accommodated in the battery casing (20).

11. A battery, characterized in that: The invention comprises the battery cell (100) as claimed in claim 10.

12. An electrical device, characterized in that: Comprising the battery of claim 11, the battery is used to provide electrical energy.

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