CN219419431U - Electrode assembly, battery cell, battery and electricity utilization device - Google Patents

Abstract

The application provides an electrode assembly, a battery cell, a battery and an electric device. The electrode assembly comprises a tab, a first area is arranged on the tab and used for welding, in the welding process, the first area with rough surface has good heat transfer performance, and heat is generated between the first area and an electrode leading-out piece, so that the surface of the first area is provided with enough heat to fuse metal, the welding compatibility of the tab and the electrode leading-out piece is improved, the occurrence of a cold joint phenomenon is reduced, the welding quality of the tab is improved, and the service life of a battery monomer is prolonged.

Description

Electrode assembly, battery cell, battery and electricity utilization device

Technical Field

The present disclosure relates to the field of batteries, and particularly to an electrode assembly, a battery cell, a battery, and an electric device.

Background

Energy conservation and emission reduction are key to sustainable development of the automobile industry, and electric vehicles become an important component of sustainable development of the automobile industry due to the energy conservation and environmental protection advantages of the electric vehicles. For electric vehicles, battery technology is an important factor in the development of the electric vehicles.

For a general battery cell, the tab is welded with an electrode lead (a current collecting member, an electrode terminal, etc.) so as to output electric energy of the battery cell. At present, the phenomenon of poor connection between the tab and the electrode lead-out piece easily occurs after the tab and the electrode lead-out piece are welded, and the service life of the battery cell is influenced.

Disclosure of Invention

In view of the above, the application provides an electrode assembly, a battery cell, a battery and an electric device, which can improve the welding quality of the tab and prolong the service life of the battery cell.

In a first aspect, the present application provides an electrode assembly comprising a tab provided with a first region for welding, the first region having a rough surface.

In the scheme of this application embodiment, electrode assembly includes the utmost point ear, is provided with the first region that is used for electrode lead-out piece welded on the utmost point ear, and first region is used for welding, and in the welding process, the heat transfer area of the first region of surface roughness is big, and heat transfer performance is good, and the heat production is many between first region and the electrode lead-out piece, makes first region surface have sufficient heat fusion metal, improves the welding compatibility of utmost point ear and electrode lead-out piece, reduces the production of rosin joint phenomenon, improves utmost point ear welding quality, promotes the free life of battery.

In some embodiments, the surface roughness Ra of the first region is 1.0 μm or greater and the surface roughness Ra of the first region is 12.5 μm or less.

In the technical scheme of the embodiment of the application, the surface roughness Ra of the first area is more than or equal to 1.0 mu m, so that the problem of poor welding quality caused by low surface energy of the first area when the surface of the first area is too smooth is solved; the surface roughness Ra of the first area is smaller than or equal to 12.5 mu m, and the problem that the electrode lug and the electrode lead-out piece are high in matching difficulty and poor in welding quality due to overlarge surface roughness of the first area is solved.

In some embodiments, the tab includes a plurality of tabs arranged in a stacked arrangement, and a first region is disposed on a surface of one side of at least one tab that is outermost, facing away from the other tabs.

In the technical scheme of this application embodiment, only set up first region on at least one utmost point ear piece in the outside of the utmost point ear piece of range upon range of setting, when improving the welding quality between utmost point ear and the electrode lead-out piece, reduced the processing degree of difficulty, improvement work efficiency.

In some embodiments, a first region is provided on each tab.

In the technical scheme of this application embodiment, all be provided with first region on every utmost point ear piece, improved the connection reliability between two adjacent utmost point ear pieces, strengthened the structural strength of utmost point ear, also improved the connection reliability of utmost point ear and electrode lead-out piece simultaneously.

In some embodiments, the area of the first region is 10% or more of the tab area.

In the technical scheme of the embodiment of the application, the area of the first area is greater than or equal to 10% of the area of the tab, so that the problems of poor tab overcurrent effect and low welding strength of the first area caused by too small first area are solved, and the battery performance is improved.

In some embodiments, the first region has an area of 100mm or more ² 。

In the technical solution of the embodiment of the application, the area of the first area is greater than or equal to 100mm ² The problems of poor tab overcurrent effect and low welding strength of the first area caused by too small first area are solved, and the battery performance is improved.

In some embodiments, the tab includes one or more tabs, and the first region completely covers at least one side surface of at least one tab in the thickness direction of the tab. In the technical scheme of the embodiment of the application, the first area completely covers at least one side surface of at least one tab in the thickness direction of the tab, so that the risk of welding effect reduction caused by misalignment of the welding head to the first area is reduced, the overcurrent efficiency of the tab is improved, and the battery performance is improved.

In some embodiments, the tab includes at least one tab, each tab having a first region disposed on both side surfaces in the thickness direction. In the technical scheme of the embodiment of the application, the first areas are formed on the two side surfaces of each tab in the thickness direction, so that the risk of welding effect reduction caused by misalignment of the welding head to the first areas is further reduced, the welding quality of the tab and the electrode lead-out piece is improved, the overcurrent efficiency of the tab is further improved, and the battery efficiency is improved.

In some embodiments, the tab further includes a second region, the roughness of the first region being greater than the roughness of the second region, the electrode assembly further comprising: and the electrode body is provided with a tab extending from at least one side of the electrode body, and the first area is positioned at one side of the second area away from the electrode body.

In the technical scheme of the embodiment of the application, the first area is located at one end, away from the electrode main body, of the second area, so that the risk of damage to the electrode main body when the first area performs welding operation is reduced.

In some embodiments, the first region is provided with a number of metal particles.

In the technical scheme of the embodiment of the application, the metal particles on the surface of the tab form the first area on the surface of the tab, so that the roughness of the first area is improved, the formation of a welding mesophase is facilitated, and the welding quality of the first area is improved.

In some embodiments, the metal particles comprise one of nickel, tin, copper, aluminum, gold, silver, and a composite metal.

In some embodiments, the tab material comprises one of copper, copper alloy, aluminum alloy, nickel alloy, iron, and stainless steel.

In a second aspect, embodiments of the present application provide a battery cell, including an electrode assembly provided in any one of the embodiments of the first aspect; and the electrode lead-out piece is connected with the tab in the first area.

In the technical solution of the embodiment of the application, the electrode lead guides the current generated by the electrode assembly to the outside.

In some embodiments, the first region includes a weld zone where the electrode lead and the tab are welded together, the weld zone having an area of 10% or more of the tab area and the weld zone having an area of 50% or less of the tab area.

In the technical scheme of the embodiment of the application, the area of the welding area is more than or equal to 10% of the area of the electrode lug, so that the problems of insufficient connection strength of the electrode lug and the electrode lead-out piece and poor overcurrent effect of the electrode lug caused by too small welding connection area of the electrode lug and the electrode lead-out piece are solved; the area of the welding area is less than or equal to 50% of the area of the tab, so that the risk of welding crack of the tab or the electrode lead-out piece caused by overlarge welding area is reduced.

In some embodiments, the tab material is different from the electrode lead material.

In the technical scheme of this application embodiment, the material of utmost point ear material is different with the material of electrode lead-out spare, has reduced the restriction requirement to the material of utmost point ear and electrode lead-out spare in the battery monomer, has reduced manufacturing cost.

In some embodiments, the electrode lead comprises one of copper, copper alloy, nickel alloy, aluminum, and aluminum alloy.

In a third aspect, embodiments of the present application provide a battery, including a battery cell provided in any one of the embodiments of the second aspect above.

In a fourth aspect, an embodiment of the present application provides an electrical device, including a battery unit provided in any one of the embodiments of the second aspect, where the battery unit is configured to provide electrical energy.

Drawings

Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The drawings are only for purposes of illustrating the preferred embodiments and are not to be construed as limiting the application. Also, like reference numerals are used to designate like parts throughout the figures. In the drawings:

FIG. 1 is a schematic view of a vehicle according to an embodiment of the present application;

fig. 2 is a schematic structural view of a battery module according to an embodiment of the present application;

fig. 3 is a schematic view of a battery module according to an embodiment of the present disclosure;

fig. 4 is a schematic structural diagram of a battery cell according to an embodiment of the present disclosure;

FIG. 5 is a schematic view of an electrode assembly according to an embodiment of the present application;

FIG. 6 is a schematic illustration of a pole piece structure of an electrode assembly according to one embodiment of the present application;

FIG. 7 is an enlarged schematic view of the structure at A in FIG. 6;

FIG. 8 is a schematic illustration of a pole piece structure of an electrode assembly according to another embodiment of the present application;

FIG. 9 is an enlarged schematic view of the structure at B in FIG. 8;

FIG. 10 is a schematic illustration of a pole piece structure of an electrode assembly provided in accordance with yet another embodiment of the present application;

FIG. 11 is an enlarged schematic view of the structure at C in FIG. 10;

fig. 12 is a schematic structural diagram of an electrode unit according to an embodiment of the present disclosure.

Reference numerals in the specific embodiments are as follows:

1 vehicle, 2 battery, 101 motor, 102 controller, 202 box, 2021 first box, 2022 second box, 201 battery module, 3 battery cell, 4 housing,

5 electrode assembly, 51 electrode body, 52 tab, 53 first region, 521 tab, 54 second region, 55 electrode lead, 56 pole piece, 6 top cap assembly, 61 electrode terminal.

Detailed Description

Embodiments of the technical solutions of the present application will be described in detail below with reference to the accompanying drawings. The following examples are only for more clearly illustrating the technical solutions of the present application, and thus are only examples, and are not intended to limit the scope of protection of the present application.

It should be noted that unless otherwise indicated, technical or scientific terms used in the embodiments of the present application should be given the ordinary meanings as understood by those skilled in the art to which the embodiments of the present application belong.

In the description of the embodiments of the present application, the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, are merely for convenience in describing the embodiments of the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be configured and operated in a specific orientation, and therefore should not be construed as limiting the embodiments of the present application.

Furthermore, the technical terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. In the description of the embodiments of the present application, the meaning of "plurality" is two or more unless explicitly defined otherwise.

In the description of the embodiments of the present application, unless explicitly specified and limited otherwise, the terms "mounted," "connected," "secured" and the like are to be construed broadly and may, for example, be fixedly connected, detachably connected, or be integrated; or may be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communicated with the inside of two elements or the interaction relationship of the two elements. The specific meaning of the above terms in the embodiments of the present application will be understood by those of ordinary skill in the art according to the specific circumstances.

In the description of embodiments of the present application, unless explicitly specified and limited otherwise, a first feature "up" or "down" on a second feature may be that the first and second features are in direct contact, or that the first and second features are in indirect contact via an intermediary. Moreover, a first feature being "above," "over" and "on" a second feature may be a first feature being directly above or obliquely above the second feature, or simply indicating that the first feature is level higher than the second feature. The first feature being "under", "below" and "beneath" the second feature may be the first feature being directly under or obliquely below the second feature, or simply indicating that the first feature is less level than the second feature.

Currently, the application of power batteries is more widespread from the development of market situation. The power battery is not only applied to energy storage power supply systems such as hydraulic power, firepower, wind power and solar power stations, but also widely applied to electric vehicles such as electric bicycles, electric motorcycles, electric automobiles and the like, and various fields such as aerospace and the like. With the continuous expansion of the application field of the power battery, the market demand of the power battery is also continuously expanding.

In the present application, the battery cells may include lithium ion secondary battery cells, lithium ion primary battery cells, lithium sulfur battery cells, sodium lithium ion battery cells, sodium ion battery cells, or magnesium ion battery cells, and the embodiment of the present application is not limited thereto. The battery cells may be cylindrical, flat, rectangular, or otherwise shaped, as well as the embodiments herein are not limited in this regard.

Reference to a battery in embodiments of the present application refers to a single physical module that includes one or more battery cells to provide higher voltage and capacity. For example, the battery referred to in the present application may include a battery module or a battery pack, or the like. The battery generally includes a case for enclosing one or more battery cells. The case body can prevent liquid or other foreign matters from affecting the charge or discharge of the battery cells.

The battery cell comprises an electrode assembly and electrolyte, wherein the electrode assembly comprises a positive electrode plate, a negative electrode plate and a separator. The battery cell mainly relies on metal ions to move between the positive pole piece and the negative pole piece to work. The positive electrode plate comprises a positive electrode current collector and a positive electrode active material layer, and the positive electrode active material layer is coated on the surface of the positive electrode current collector; the positive current collector comprises a positive current collecting part and a positive lug connected to the positive current collecting part, wherein the positive current collecting part is coated with a positive active material layer, and the positive lug is not coated with the positive active material layer. Taking a lithium ion battery as an example, the material of the positive electrode current collector may be aluminum, the positive electrode active material layer includes a positive electrode active material, and the positive electrode active material may be lithium cobaltate, lithium iron phosphate, ternary lithium, lithium manganate or the like. The negative electrode plate comprises a negative electrode current collector and a negative electrode active material layer, and the negative electrode active material layer is coated on the surface of the negative electrode current collector; the negative electrode current collector comprises a negative electrode current collecting part and a negative electrode tab connected to the negative electrode current collecting part, wherein the negative electrode current collecting part is coated with a negative electrode active material layer, and the negative electrode tab is not coated with the negative electrode active material layer. The material of the anode current collector may be copper, the anode active material layer includes an anode active material, and the anode active material may be carbon or silicon, or the like. The material of the separator may be PP (polypropylene) or PE (polyethylene), etc.

The inventors of the present application noted that the service life of some batteries was not up to standard.

The inventor disassembles the battery, disassembles the battery cell in the battery, and analyzes and researches the structure and the service environment of the battery cell. The inventors found that the contact between the tab and the electrode lead-out member in part of the battery cell was poor, or the tab was separated from the electrode lead-out member, or the contact between the tab pieces was poor, or the tab pieces were separated from each other. Further research shows that in the manufacturing process of the battery monomer, the tab and the electrode lead-out piece are required to be welded, and along with the diversification of designs, the research of using the high-strength metal (such as stainless steel) as the pole piece foil material is gradually increased, but the welding difficulty of the high-strength metal tab and the electrode lead-out piece is high, and especially when the tab and the electrode lead-out piece are dissimilar metals, the welding difficulty is further increased. When the electrode tab and the electrode lead-out piece are welded by ultrasonic waves, the friction heat generation between the electrode tab and the electrode lead-out piece and between the electrode tab and the electrode lead-out piece is insufficient, so that the risk of cold welding is increased, poor contact between the electrode tab and the electrode lead-out piece in a battery cell is caused, the overcurrent resistance of the electrode tab is large, the internal heat generation is serious, the strength of the electrode lead-out piece and the electrode tab is not up to standard, and the problem that the electrode tab and the electrode lead-out piece are separated is solved, thereby the service life of the battery is reduced.

Based on the above problems found by the inventors, the inventors have improved an electrode assembly, in which a first region for welding an electrode lead-out member is provided on a tab, the first region is used for welding, and in the welding process, the first region having a rough surface has a larger heat transfer area and good heat transfer performance, and generates more heat between the first region and the electrode lead-out member, so that the surface of the first region has enough heat to fuse metals, the welding compatibility of the tab and the electrode lead-out member is improved, the occurrence of a cold welding phenomenon is reduced, the welding quality of the tab is improved, and the service life of a battery cell is prolonged.

The technical scheme described in the embodiment of the application is applicable to batteries and power utilization devices using the batteries.

The electric device may be a vehicle, a mobile phone, a portable device, a notebook computer, a ship, a spacecraft, an electric toy, an electric tool, or the like. The vehicle can be a fuel oil vehicle, a fuel gas vehicle or a new energy vehicle, and the new energy vehicle can be a pure electric vehicle, a hybrid electric vehicle or a range-extended vehicle; spacecraft including airplanes, rockets, space planes, spacecraft, and the like; the electric toy includes fixed or mobile electric toys, such as a game machine, an electric car toy, an electric ship toy, and an electric airplane toy; power tools include metal cutting power tools, grinding power tools, assembly power tools, and railroad power tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete shakers, and electric planers, among others. The embodiment of the application does not limit the electric device in particular.

It should be understood that the technical solutions described in the embodiments of the present application are not limited to the above-described batteries and electric devices, but may be applied to all batteries including a case and electric devices using the batteries, but for simplicity of description, the following embodiments are described by taking an electric vehicle as an example.

Referring to fig. 1, fig. 1 is a schematic structural diagram of a vehicle 1 according to some embodiments of the present application. The vehicle 1 can be a fuel oil vehicle, a fuel gas vehicle or a new energy vehicle, and the new energy vehicle can be a pure electric vehicle, a hybrid electric vehicle or a range-extending vehicle. The interior of the vehicle 1 is provided with a battery 2, which may be provided at the bottom or at the head or at the tail of the vehicle 1. The battery 2 may be used for power supply of the vehicle 1, for example, the battery 2 may serve as an operating power source of the vehicle 1. The vehicle 1 may also include a controller 102 and a motor 101, the controller 102 being configured to control a battery to power the motor 101, for example, for operating power requirements during start-up, navigation, and travel of the vehicle 1.

In some embodiments of the present application, the battery may not only serve as an operating power source for the vehicle 1, but also as a driving power source for the vehicle 1, providing driving power for the vehicle 1 instead of or in part instead of fuel oil or natural gas.

To meet different demands for power use, the battery 2 may include a plurality of battery cells, which means the smallest units constituting a battery module or a battery pack. Multiple cells may be connected in series and/or parallel via electrode terminals for use in various applications. The battery 2 mentioned in the present application includes a battery module or a battery pack. The battery cells can be connected in series or parallel or in series-parallel connection, and the series-parallel connection refers to the mixture of series connection and parallel connection. In the embodiment of the application, a plurality of battery monomers can directly form a battery pack, or can form a battery module first, and the battery module forms the battery pack again.

Fig. 2 shows a schematic structural diagram of a battery 2 according to an embodiment of the present application.

As shown in fig. 2, the battery includes a case 202 and a battery cell (not shown) housed in the case 202.

The case 202 may have a simple three-dimensional structure such as a rectangular parallelepiped, a cylinder, or a sphere, or may have a complex three-dimensional structure formed by combining simple three-dimensional structures such as a rectangular parallelepiped, a cylinder, or a sphere. The material of the case 202 may be an alloy material such as aluminum alloy or iron alloy, a polymer material such as polycarbonate or polyisocyanurate foam, or a composite material such as glass fiber and epoxy resin.

The case 202 is used to house the battery cells, and the case 202 may have various structures. In some embodiments, the case 202 may include a first case portion 2021 and a second case portion 2022, where the first case portion 2021 and the second case portion 2022 are mutually covered, and the first case portion 2021 and the second case portion 2022 together define an accommodating space for accommodating the battery cell 3. The second housing portion 2022 may be a hollow structure having one end opened, the first housing portion 2021 is a plate-like structure, and the first housing portion 2021 is covered on the opening side of the second housing portion 2022 to form the housing 202 having an accommodation space; the first housing portion 2021 and the second housing portion 2022 may each be a hollow structure having an opening at one side, and the opening side of the first housing portion 2021 is covered with the opening side of the second housing portion 2022 to form the housing 202 having the accommodation space. Of course, the first housing portion 2021 and the second housing portion 2022 may be of various shapes, such as a cylinder, a rectangular parallelepiped, or the like.

In order to improve the sealing property after the first housing portion 2021 and the second housing portion 2022 are connected, a sealing member, such as a sealant, a seal ring, or the like, may be provided between the first housing portion 2021 and the second housing portion 2022.

Assuming that the first housing portion 2021 is covered on top of the second housing portion 2022, the first housing portion 2021 may also be referred to as an upper cover, and the second housing portion 2022 may also be referred to as a lower cover.

In the battery 2, the number of battery cells may be one or more. If the number of the battery cells is multiple, the multiple battery cells can be connected in series or in parallel or in series-parallel connection, and the series-parallel connection means that the multiple battery cells are connected in series or in parallel. The plurality of battery cells can be directly connected in series or in parallel or in series-parallel, and then the whole formed by the plurality of battery cells is accommodated in the box 202; of course, a plurality of battery cells may be connected in series or parallel or in series to form the battery module 201, and then the plurality of battery modules 201 are connected in series or parallel or in series to form a whole and are accommodated in the case 202.

Fig. 3 shows a schematic structural view of a battery module 201 according to an embodiment of the present application.

In some embodiments, as shown in fig. 2 and 3, the battery cells 3 are plural, and the plural battery cells 3 are first connected in series or parallel or series-parallel to form the battery module 201. The plurality of battery modules 201 are then connected in series or parallel or a series-parallel combination to form a unit and are accommodated in the case 202.

The plurality of battery cells 3 in the battery module 201 may be electrically connected through a bus bar member to realize parallel connection or series-parallel connection of the plurality of battery cells 3 in the battery module 201.

In the present application, the battery cell 3 may include a lithium ion battery cell 3, a sodium ion battery cell 3, a magnesium ion battery cell 3, or the like, which is not limited in the embodiment of the present application. The battery cell 3 may be in a cylindrical shape, a flat shape, a rectangular parallelepiped shape, or other shapes, etc., which is not limited in the embodiment of the present application. The battery cells 3 are generally divided into three types in a package manner: the cylindrical battery cell 3, the prismatic battery cell 3, and the pouch battery cell 3 are not limited thereto in this embodiment. However, for simplicity of description, the following embodiments will take the square battery cell 3 as an example.

Fig. 4 is a schematic structural diagram of a battery cell 3 according to some embodiments of the present application. The battery cell 3 refers to the smallest unit constituting the battery. As shown in fig. 4, the battery cell 3 includes a top cap assembly 6, a case 4, and an electrode assembly 5.

The electrode assembly 5 is a component in which electrochemical reactions occur in the battery cells 3. One or more electrode assemblies 5 may be contained within the case 4. The electrode assembly 5 is mainly formed by winding or stacking a pole piece, which is divided into a positive pole piece and a negative pole piece, and a separator is generally provided between the positive pole piece and the negative pole piece. The portions of the positive electrode sheet and the negative electrode sheet having the active material constitute the electrode body 51, and the portions of the positive electrode sheet and the negative electrode sheet having no active material constitute the tabs 52, respectively. The positive electrode tab and the negative electrode tab may be located at one end of the main body portion together or located at two ends of the main body portion respectively. During charge and discharge of the battery, the positive electrode active material and the negative electrode active material react with the electrolyte, and the tab 52 is connected to the electrode terminal 61 to form a current loop.

The case 4 is an assembly for cooperating with the top cap assembly 6 to form an internal environment of the battery cell 3, wherein the formed internal environment may be used to accommodate the electrode assembly 5, an electrolyte (not shown in the drawings), and other components. The case 4 and the top cap assembly 6 may be separate members, and an opening may be provided in the case 4 to form an internal environment of the battery cell 3 by covering the opening with the top cap assembly 6 at the opening. Alternatively, the top cover assembly 6 and the housing 4 may be integrated. Alternatively, the cap assembly 6 and the housing 4 may be formed with a common connection surface prior to the other components being housed, and the cap assembly 6 is then allowed to cover the housing 4 when it is desired to encapsulate the interior of the housing 4. The housing 4 may be of various shapes and sizes, such as rectangular parallelepiped, cylindrical, hexagonal prism, etc. The shape of the case 4 may be determined according to the specific shape and size of the electrode assembly 5. The material of the housing 4 may be various, and optionally, the material of the housing 4 may be copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc.

In some embodiments, as shown in fig. 4, two electrode terminals 61 may be provided in the top cap assembly 6. One electrode terminal 61 of the cap assembly 6 is electrically connected to one tab 52 (e.g., positive tab) of the electrode assembly 5. The other electrode terminal 61 in the cap assembly 6 is electrically connected with the other tab 52 (e.g., negative tab) of the electrode assembly 5.

In other embodiments, the housing 4 may have two openings. Two openings are provided on opposite sides of the housing 4. The top cover assembly 6 is two. The two top cover assemblies 6 are respectively covered at the two openings of the shell 4. In this case, the electrode terminal 61 in the cap assembly 6 may be one. The electrode terminal 61 in one cap assembly 6 is electrically connected with one tab 52 (e.g., positive tab) of the electrode assembly 5; the electrode terminal 61 of the other cap assembly 6 is electrically connected with the other tab 52 (e.g., negative tab) of the electrode assembly 5.

Referring to fig. 5, 6 and 7, fig. 5 is a schematic structural view of an electrode assembly 5 according to an embodiment of the present application, fig. 6 is a schematic structural view of a pole piece 56 of the electrode assembly 5 according to an embodiment of the present application, and fig. 7 is an enlarged schematic structural view at a in fig. 6.

The embodiment of the application provides an electrode assembly, as shown in fig. 5 to 7, the electrode assembly 5 includes a tab 52, a first region 53 is disposed on the tab 52, the first region 53 is used for welding, and a surface of the first region 53 is rough.

The first region 53 is a region on the tab 52 for welding with the electrode lead-out member 55, and the surface roughness of the first region 53 refers to that the surface roughness of the first region 53 of the tab 52 is high in the embodiment of the present application compared to the surface of the tab 52 in the conventional technical means.

The surface roughness (surface roughness) refers to the roughness of small pitches and minute peaks and valleys of a processed surface (e.g., tab surface). The smaller the surface roughness, the smoother the surface.

Alternatively, the first region 53 may be formed on the surface of the tab 52 by machining, such as embossing, hobbing, etc., or a portion of the protrusion may be formed on the tab 52 during the preparation of the pole piece 56 to form the first region 53.

Alternatively, the first region 53 may cover at least one side surface of the tab 52 in the thickness direction of the tab 52.

Alternatively, in the thickness direction of the tab 52, the first region 53 covers a part of the surface of the tab 52, and the shape of the first region 53 may be a regular planar pattern or an irregular pattern. Alternatively, the first region 53 is regular polygon or circular or triangular.

Alternatively, a plurality of tabs 521 and a plurality of first regions 53 may be provided in one electrode assembly 5.

Alternatively, the plurality of first regions 53 may have the same shape and area within the same electrode assembly 5.

Alternatively, the first region 53 may be disposed on the base material of the pole piece 56 before the step of cutting the pole piece 52, where the step of cutting the pole piece 52 refers to cutting the base material of the pole piece 56, which is not coated with the active material layer, into the pole piece 52 with a suitable shape during the preparation process of the pole piece 52.

Alternatively, the first region 53 may be separately provided on at least a portion of the tab 52 after the tab 52 cutting step.

Optionally, the welding mode is ultrasonic welding, the first area 53 with rough surface has large heat transfer area and good heat conduction performance, and the friction heat generation of the first area 53 is large, so that enough heat is generated on the surface of the first area 53 to fuse metal, the welding compatibility of the tab 52 and the electrode lead-out piece is improved, the occurrence of the cold joint phenomenon is reduced, and the welding quality of the tab 52 is improved.

Alternatively, the welding mode is laser welding, and when the welding mode is laser welding, the rough first area 53 reduces energy loss caused by reflection of laser in the first area 53, and improves the welding effect of the tab 52.

In these embodiments, the electrode assembly 5 includes the tab 52, the tab 52 is provided with the first area 53 for welding the electrode lead-out member, the first area 53 is used for welding, in the welding process, the first area 53 with rough surface has good heat transfer performance, the heat generation between the first area 53 and the electrode lead-out member is much, so that the surface of the first area 53 has enough heat to fuse metal, the welding compatibility of the tab 52 and the electrode lead-out member is improved, the occurrence of the cold welding phenomenon is reduced, the welding quality of the tab 52 is improved, and the service life of the battery cell is prolonged.

In some alternative embodiments, as shown in fig. 5, the surface roughness Ra of the first region 53 is 1.0 μm or more, and the surface roughness Ra of the first region 53 is 12.5 μm or less.

Alternatively, the surface roughness Ra of the first region 53 is 3.2 μm or more, and the surface roughness Ra of the first region 53 is 6.3 μm or less.

In these alternative embodiments, the surface roughness Ra of the first region 53 is 1.0 μm or more, improving the problem of poor welding quality due to the surface of the first region 53 being too smooth and the surface energy of the first region 53 being low during welding; the surface roughness Ra of the first region 53 is less than or equal to 12.5 μm, and the problem that the tab 52 and the electrode lead are difficult to match and the welding quality of the tab 52 and the electrode lead is poor due to the overlarge surface roughness of the first region 53 is solved.

In some alternative embodiments, as shown in fig. 5 to 7, the tab 52 includes a plurality of tabs 521 disposed in a stacked manner, and the first region 53 is disposed on a surface of at least one tab 521 on the outermost side facing away from the other tabs 521.

The electrode lead-out piece is connected with the electrode lead-out piece, and the electrode lead-out piece can be a switching component for connecting the electrode terminal and the electrode lug, or the electrode lead-out piece is an electrode terminal.

Alternatively, the outermost one of the tabs 521 is provided with the first region 53 on the surface of the tab 521 which is not in contact with the other tab 521.

In these alternative embodiments, the first region 53 is provided only on at least one tab 521 on the outermost side of the tabs 521 that are stacked, so that the welding quality between the tab 52 and the electrode lead 55 is improved, and the processing difficulty is reduced, and the working efficiency is improved.

In some alternative embodiments, as shown in fig. 5-7, a first region 53 is provided on each tab 521.

The electrode assembly 5 includes a plurality of tab pieces 521, and each tab piece 521 is provided with a first region 53, so that connection reliability between two adjacent tab pieces 521 is improved, structural strength of the tab 52 is enhanced, and connection reliability between the tab 52 and an electrode lead of a battery cell is also improved.

The electrode assembly 5 comprises a plurality of electrode tabs 52 which are stacked, the first areas 53 are arranged on the two electrode tabs 521 at the outermost side, and the first areas 53 are arranged on the two electrode tabs 521 at the outermost side, so that the preparation difficulty is reduced, the fault tolerance of the connection of the electrode tabs 521 and the electrode lead-out member is improved, and the practicability of the electrode assembly 5 is improved.

Alternatively, the first region 53 on each tab 521 may have the same shape or different sizes.

Alternatively, in the thickness direction of the tab 521, only the first area is disposed on one side surface of the tab 521, so as to reduce the processing difficulty of the tab 521.

Alternatively, each tab 521 is provided with the first region 53 on both side surfaces in the thickness direction.

In these alternative embodiments, the first region 53 is disposed on each tab 521, which improves the connection reliability between two adjacent tabs 521, enhances the structural strength of the tab 52, and improves the connection reliability between the tab 52 and the electrode lead-out member of the battery cell.

In some alternative embodiments, as shown in fig. 5-7, the area of the first region 53 is 10% or more of the area of the tab 52.

The area of the tab 52 refers to the area of one side surface of the tab 52 in the thickness direction of the tab 52. The area of the first region 53 being 10% or more of the area of the tab 52 means that the area occupied by the first region 53 is 10% or more of the area of the tab 52 on one side surface in the thickness direction of the tab 52.

Alternatively, the area of the first region 53 may be 25% -30% of the tab area.

In these alternative embodiments, the area of the first region 53 is 10% or more of the area of the tab 52, which improves the problems of poor overcurrent effect of the tab 52 and low welding strength of the first region 53 due to the excessively small first region 53, and improves the battery performance.

In some alternative embodiments, as shown in FIGS. 5-7, the area of the first region 53 is 100mm or more ² 。

Optionally, the area of the first region 53 is 150mm or less ² And the area of the first region 53 is 100mm or more ² 。

In these embodiments, the area of the first region 53 is 100mm or more ² The problems of poor overcurrent effect of the tab 52 and low welding strength of the first region 53 caused by too small first region 53 are solved, and the battery performance is improved.

Referring to fig. 8 and 9, fig. 8 is a schematic view of a pole piece 56 of an electrode assembly according to another embodiment of the present application, and fig. 9 is an enlarged schematic view of a portion B in fig. 8.

In some alternative embodiments, as shown in fig. 8 and 9, the tab 52 includes one or more tabs 521, and the first region 53 entirely covers at least one side surface of at least one tab 521 in the thickness direction of the tab 52.

Alternatively, one electrode assembly is provided with a plurality of tabs 52, and the first region 53 is identical in shape and size at the position on each tab 52.

In these alternative embodiments, the tab 52 includes one or more tabs 521, the first region 53 completely covers at least one side surface of at least one tab 521 in the thickness direction of the tab 52, the risk of reduced welding effect due to misalignment of the welding head to the first region 53 is reduced, and the overcurrent efficiency of the tab 52 is improved, improving the battery performance.

In some alternative embodiments, as shown in fig. 8 and 9, the tab 52 includes at least one tab 521, and each tab 521 is provided with a first region 53 on both side surfaces in the thickness direction.

Alternatively, the first region 53 is disposed on the entire active material layer-uncoated pole piece 56 substrate prior to the tab 52 cutting step, and the first region 53 covers the entire tab 52 surface after the tab 52 is cut.

In these alternative embodiments, the tab 52 includes at least one tab 521, and the first areas 53 are disposed on two side surfaces of each tab 521 in the thickness direction, which further reduces the risk of reducing the welding effect due to misalignment of the welding head with respect to the first areas 53, improves the welding quality between the tab 52 and the electrode lead-out member, and further improves the overcurrent efficiency of the tab 52, and improves the battery efficiency.

Referring to fig. 10, 11 and 12, fig. 10 is a schematic structural view of a pole piece 56 of an electrode assembly according to another embodiment of the present application, fig. 11 is an enlarged schematic structural view at C in fig. 10, and fig. 12 is a schematic structural view of an electrode unit 3 according to an embodiment of the present application.

In some alternative embodiments, as shown in fig. 10 to 12, the tab 52 further includes a second region 54, the roughness of the first region 53 is greater than the roughness of the second region 54, and the electrode assembly 5 further includes: the electrode body 51, the tab 52 protrudes from at least one side of the electrode body 51, and the first region 53 is located on a side of the second region 54 remote from the electrode body 51.

The second region 54 refers to the other region on the tab 52 than the first region 53.

High temperature and debris are generated during the welding operation, and the first region 53 is located on the side of the second region 54 away from the electrode main body 51, so that the risk of short circuit of the battery caused by invasion of welding debris into the electrode main body is reduced, and the risk of damage to components (such as a diaphragm) in the electrode main body 51 and short circuit of the battery caused by high temperature is reduced.

Alternatively, in the first direction X, the first region 53 and the second region 54 are arranged side by side.

Optionally, the second region 54 is not subjected to a roughness-enhancing treatment.

In these alternative embodiments, the roughness of the second region 54 is less than the roughness of the first region 53, reducing the time required to increase the surface roughness of the second region 54, reducing the difficulty in machining the tab 52, and increasing the efficiency of operation, the first region 53 being located at the end of the second region 54 remote from the electrode body 51, reducing the risk of damage to the electrode body 51 during the welding operation of the first region 53.

In some alternative embodiments, as shown in fig. 10 and 12, the first region 53 is provided with a number of metal particles.

Alternatively, the metal particles may be coated by spraying, sputtering, electroless plating, or the like.

Alternatively, the tab 52 and the electrode lead-out member 55 are not the same metal, and the welding quality is easily reduced due to the fact that brittleness is equal during welding due to the difference of physical and chemical characteristics of the tab 52 and the electrode lead-out member 55 during welding, and metal particles are added during welding, so that the metal particles contribute to the generation of a welding mesophase during welding, the element distribution, the phase composition and the microstructure morphology of a dissimilar metal interface can be changed, the generation of substances unfavorable for welding such as brittle intermetallic metal compounds is reduced, and the conditions that fine grains and the like are favorable for improving the welding quality are achieved.

In these embodiments, the plurality of metal particles on the surface of the tab 52 form the first region 53 of the surface of the tab 52, increasing the roughness of the first region 53 and helping to form a weld mesophase, improving the weld quality of the first region 53.

In some alternative embodiments, as shown in fig. 12, the metal particles may be made of one of nickel, tin, copper, aluminum, gold, silver, and composite metals.

In some alternative embodiments, as shown in fig. 12, the tab material includes one of copper, copper alloy, aluminum alloy, nickel alloy, iron, and stainless steel.

The embodiment of the present application provides a battery cell 3, as shown in fig. 12, including the electrode assembly 5 provided in any of the embodiments described above; the electrode lead-out member 55 is connected to the tab 52 at the first region 53.

Alternatively, the electrode lead-out member 55 is a switching member, or the electrode lead-out member 55 is an electrode terminal.

In these embodiments, the electrode lead 55 guides the current generated by the electrode assembly 5 to the outside.

In some alternative embodiments, as shown in fig. 12, the first region 53 includes a welding zone (not shown) where the electrode lead-out member 55 and the tab 52 are welded together, the area of the welding zone being 10% or more of the area of the tab 52, and the area of the welding zone being 50% or less of the area of the tab 52.

The first region 53 on the tab 52 is used for welding, but after the welding operation is completed, the first region 53 is not necessarily completely welded to the electrode lead 55. The first region 53 is entirely welded to the electrode lead-out member 55, and the welding region is provided in the first region 53, and the area of the welding region is equal to or smaller than the area of the first region 53.

In the embodiments, the area of the welding area is greater than or equal to 10% of the area of the tab 52, so that the problems of insufficient connection strength between the tab 52 and the electrode lead-out member 55 and poor overcurrent effect of the tab 52 caused by too small welding area and too small welding connection area between the tab 52 and the electrode lead-out member 55 are solved; the area of the weld area is 50% or less of the area of the tab 52, reducing the risk of the weld area being too large, resulting in cracking of the tab 52 or electrode lead-out 55 during welding.

In some alternative embodiments, as shown in fig. 12, the tab 52 is a different material than the electrode lead 55.

Optionally, the tab 52 is made of stainless steel, and the cost of the stainless steel tab 52 is low. The electrode lead-out sheet 55 is copper and has high structural strength.

In these embodiments, the tab 52 is made of a different material than the electrode lead-out 55, which reduces the requirements for limiting the material of the tab 52 and the electrode lead-out 55 in the cell and reduces the production cost.

In some alternative embodiments, as shown in fig. 12, the electrode lead-out member 55 comprises one of copper, copper alloy, nickel alloy, aluminum, and aluminum alloy.

The embodiment of the application provides a battery, which comprises the battery cell provided by the embodiment.

The embodiment of the application provides an electricity utilization device, which comprises a battery cell provided by the embodiment, wherein the battery cell is used for providing electric energy.

According to some embodiments of the present application, as shown in fig. 1 to 12, the present application provides an electrode assembly 5, where the electrode assembly 5 includes a tab 52, a first region 53 for welding is disposed on the tab 52, a surface of the first region 53 is rough, a surface roughness Ra of the first region 53 is 1.0 μm or more, and a surface roughness Ra of the first region 53 is 12.5 μm or less, an area of the first region 53 is 10% or more of an area of the tab 52, the first region 53 is composed of a plurality of metal particles located on a surface of the tab, a material of the metal particles includes one of nickel, tin, copper, aluminum, gold, silver, and a composite metal, and a material of the tab 52 includes one of copper, copper alloy, aluminum alloy, nickel alloy, iron, and stainless steel.

The tab 52 further includes a second region 54, the roughness of the first region 53 is greater than the roughness of the second region 54, the electrode assembly 5 further includes an electrode body 51, the tab 52 extends from at least one side of the electrode body 51 in the first direction X, and the first region 53 is located on a side of the second region 54 remote from the electrode body 51.

In these embodiments, the electrode assembly 5 includes the tab 52, the tab 52 is provided with the first area 53 for welding the electrode lead-out member 55, the first area 53 is used for welding, in the welding process, the heat transfer area of the first area 53 with rough surface is large, the heat transfer performance is good, the heat generation is much between the first area 53 and the electrode lead-out member 55, so that the surface of the first area 53 has enough heat to fuse metal, the welding compatibility of the tab 52 and the electrode lead-out member 55 is improved, the occurrence of the cold welding phenomenon is reduced, the welding quality of the tab 52 is improved, and the service life of the battery cell 3 is prolonged.

Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present application, and not for limiting the same; although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some or all of the technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit of the embodiments, and are intended to be included within the scope of the claims and description. In particular, the technical features mentioned in the respective embodiments may be combined in any manner as long as there is no structural conflict. The present application is not limited to the specific embodiments disclosed herein, but encompasses all technical solutions falling within the scope of the claims.

Claims (16)

1. The electrode assembly is characterized by comprising a tab, wherein a first area is arranged on the tab and used for welding, the surface of the first area is rough, the first area is provided with a plurality of metal particles, the surface roughness Ra of the first area is greater than or equal to 1.0 mu m, and the surface roughness Ra of the first area is less than or equal to 12.5 mu m.

2. The electrode assembly according to claim 1, wherein the tab includes a plurality of tab pieces arranged in a stacked manner, and the first region is provided on a surface of at least one of the tab pieces on the outermost side facing away from the other tab pieces.

3. The electrode assembly of claim 1, wherein the first region is disposed on each tab.

4. The electrode assembly of claim 1, wherein the area of the first region is 10% or more of the tab area.

5. The electrode assembly of claim 4, wherein the first region has an area of 100mm or more ² 。

6. The electrode assembly of claim 1, wherein the tab comprises one or more tabs, the first region completely covering at least one side surface of at least one of the tabs in the thickness direction of the tab.

7. The electrode assembly according to any one of claims 1 to 6, wherein the tab includes at least one tab, and both side surfaces of each tab in a thickness direction are provided with the first region.

8. The electrode assembly of claim 1, wherein the tab further comprises a second region, the first region having a roughness greater than a roughness of the second region,

the electrode assembly further includes:

an electrode body, the tab protruding from at least one side of the electrode body,

the first region is located on a side of the second region remote from the electrode body.

9. The electrode assembly of claim 1, wherein the metal particles comprise one of nickel, tin, copper, aluminum, gold, silver, and a composite metal.

10. The electrode assembly of claim 1, wherein the tab material comprises one of copper, copper alloy, aluminum alloy, nickel alloy, iron, and stainless steel.

11. A battery cell, comprising:

the electrode assembly of any one of claims 1-10;

and the electrode lead-out piece is connected with the tab in the first area.

12. The battery cell of claim 11, wherein the first region comprises a weld zone where the electrode lead and the tab are welded together, the weld zone having an area of 10% or more of the tab area and an area of 50% or less of the tab area.

13. The battery cell of claim 11, wherein the tab material is different from the electrode lead-out material.

14. The battery cell of claim 11, wherein the electrode lead comprises one of copper, copper alloy, nickel alloy, aluminum, and aluminum alloy.

15. A battery comprising a cell according to any one of claims 11-14.

16. An electrical device comprising a cell according to any one of claims 11-14 for providing electrical energy.