ELECTRODE SHEET AND PRODUCING METHOD THEREOF, AND RELATED DEVICE

An electrode sheet includes a current collector as well as an insulating layer and an active material layer arranged on the current collector along a first direction, the insulating layer is first formed on the current collector, and then the active material layer is formed on the current collector, so that an edge portion on one side of the active material layer close to the insulating layer covers a first edge region of the insulating layer.

TECHNICAL FIELD

The present application relates to the field of battery technologies, and in particular, to an electrode sheet and a producing method thereof, an electrode assembly, a battery cell, a battery, and a power consumption device.

BACKGROUND

Energy conservation and emission reduction are the key to the sustainable development of the automotive industry. In this case, electric vehicles have become an important part of the sustainable development of the automotive industry due to their advantages of energy conservation and environmental protection. For the electric vehicles, the battery technology is an important factor for their development.

In the development of battery technology, the quality of an electrode assembly is closely related to the capacity and safety performance of a battery. The quality of an electrode sheet in the electrode assembly is particularly important, and it will directly affect the quality of the electrode assembly. Therefore, how to improve quality of an electrode sheet is an urgent technical problem to be solved in the battery technology.

SUMMARY

Embodiments of the present application provide an electrode sheet and a producing method thereof, an electrode assembly, a battery cell, a battery, and a power consumption device, which could avoid the problem of coating bulging edge caused by migration of an insulating layer on a current collector to an active material layer, and be beneficial to obtaining an electrode sheet with higher final quality.

In a first aspect, an electrode sheet is provided, including: a current collector as well as an insulating layer and an active material layer located on the current collector; where the active material layer and the insulating layer are arranged along a first direction of the current collector, and an edge portion on one side of the active material layer close to the insulating layer covers a first edge region of the insulating layer.

In the embodiments of the present application, on the current collector, the edge portion on one side of the active material layer close to the insulating layer covers the first edge region of the insulating layer. That is, the insulating layer is first formed on the current collector by coating and drying, and then the active material layer is formed on the current collector, so that the edge portion of the active material layer covers the first edge region of the insulating layer. This can limit the migration of a liquid insulating layer slurry to the active material layer, which could effectively avoid the problem of coating bulging edge caused by migration of the insulating layer to the active material layer, and be beneficial to improving processing efficiency and processing quality of the electrode sheet and obtaining an electrode sheet with higher final quality. In addition, the edge portion on one side of the active material layer close to the insulating layer covers the first edge region of the insulating layer, that is, there is no directly exposed current collector between the active material layer and the insulating layer. This is beneficial to avoiding the phenomenon of puncturing a separator by generating wrinkles at the exposed current collector due to the effect of stress concentration, and is further beneficial to improving the safety of a battery.

In a possible implementation manner, in the first direction, a tab of the current collector is located on one side of the insulating layer away from the active material layer.

In the embodiment of the present application, the insulating layer is located between the tab and the active material layer, which is beneficial to ensuring that the edge of the electrode sheet has good insulation performance, thereby reducing the risk of a short circuit of the battery and improving the safety performance of the battery.

In a possible implementation manner, a second edge region of the insulating layer covers an end region on one side of the tab close to the active material layer.

In the embodiment of the present application, the second edge region of the insulating layer covers the end region on one side of the tab closes to the active material layer, which is beneficial to ensuring the insulation of the position of the tab, so as to be beneficial to ensuring that the edge of the electrode sheet has good insulation performance after the electrode sheet is packaged, thereby reducing the risk of a short circuit of the battery and improving the safety performance of the battery.

In a possible implementation manner, a thickness of the insulating layer ranges from 1 μm to 25 μm.

In a possible implementation manner, the thickness of the insulating layer ranges from 2 μm to 10 μm.

In the embodiment of the present application, the thickness of the insulating layer is set reasonably, which is beneficial not only to ensuring that the insulating layer plays the role of insulation and protection, but also to bending the tab more easily, thereby reducing the space for bending the tab to improve the volumetric energy density of the battery.

In a possible implementation manner, in the first direction, a size of the edge portion ranges from 0 to 5 mm.

In the embodiment of the present application, the size of the edge portion of the active material layer in the first direction is set to range from 0 to 5 mm, which allows there to be no directly exposed current collector between the active material layer and the insulating layer, and does not occupy more active material regions.

In a possible implementation manner, the electrode sheet further includes a conductive layer, the conductive layer is located between the current collector and the active material layer, and the active material layer completely covers the conductive layer.

In the embodiment of the present application, the conductive layer contains a conductive agent and a binder, and it has relatively high conductivity and bonding, which is beneficial not only to improving the conductivity of the electrode sheet and reducing the internal resistance of the battery, but also to enhancing the adhesion between the active material layer and the current collector.

In a possible implementation manner, in the first direction, a gap is provided between the conductive layer and the insulating layer.

In the embodiment of the present application, the gap is provided between the conductive layer and the insulating layer, which is beneficial to avoiding mutual interference between the insulating layer and the conductive layer in the producing process, so as to ensure that the formed conductive layer and insulating layer play their respective roles.

In a possible implementation manner, in the first direction, a size of the gap ranges from 0.1 mm to 4 mm.

In a possible implementation manner, in the first direction, the size of the gap ranges from 0.5 mm to 1 mm.

In the embodiment of the present application, the size of the gap between the conductive layer and the insulating layer is set reasonably, which is beneficial not only to avoiding the mutual interference between the conductive layer and the insulating layer in the producing process, but also to reducing the adverse effects on the internal resistance of the battery and the adhesion between the active material layer and the current collector since the position of the gap lacks the conductive layer.

In a possible implementation manner, a thickness of the conductive layer ranges from 0.5 μm to 2 μm.

In the embodiment of the present application, the thickness of the conductive layer is set to range from 0.5 μm to 2 μm, which is beneficial not only to ensuring that the conductive layer plays a role in the electrode sheet, but also to avoiding the reduction of the energy density of the battery caused by the excessive thickness of the conductive layer.

In a possible implementation manner, the insulating layer and the active material layer are sequentially formed on the current collector by coating and drying.

In the embodiment of the present application, the insulating layer is first formed on the current collector by coating and drying, and then the active material layer is formed on the current collector. This can limit the migration of the liquid insulating layer slurry to the active material layer, which could effectively avoid the problem of coating bulging edge caused by migration of the insulating layer to the active material layer, and be beneficial to improving processing efficiency and processing quality of the electrode sheet and obtaining an electrode sheet with higher final quality.

In a possible implementation manner, the insulating layer is formed on the current collector by coating and drying using a micro-gravure coating process.

In the embodiment of the present application, compared with the commonly used die extrusion coating process, the use of micro-gravure coating is beneficial to reducing the thickness of the insulating layer. In this way, the thickness of the insulating layer covering the end region on one side of the tab close to the active material layer is reduced, which makes the tab soft and easier to be bent, and is further beneficial to reducing the space for bending the tab in the process of packaging the battery and increasing the volumetric energy density of the battery.

In a second aspect, a producing method of an electrode sheet is provided, including: coating an insulating layer slurry on a current collector to form an insulating layer after drying; and coating an active material layer slurry on the current collector to form an active material layer after drying, so as to obtain the electrode sheet; where the active material layer and the insulating layer are arranged along a first direction of the current collector, and an edge portion on one side of the active material layer close to the insulating layer covers a first edge region of the insulating layer.

In the embodiment of the present application, the insulating layer is first formed on the current collector by coating and drying, and then the active material layer is formed on the current collector. This can limit the migration of the liquid insulating layer slurry to the active material layer, which could effectively avoid the problem of coating bulging edge caused by migration of the insulating layer to the active material layer, and be beneficial to improving processing efficiency and processing quality of the electrode sheet and obtaining an electrode sheet with higher final quality. In addition, the edge portion on one side of the active material layer close to the insulating layer covers the first edge region of the insulating layer, that is, there is no directly exposed current collector between the active material layer and the insulating layer. This is beneficial to avoiding the phenomenon of puncturing a separator by generating wrinkles at the exposed current collector due to the effect of stress concentration, and is further beneficial to improving the safety of a battery.

In a possible implementation manner, the method further includes: processing, in the first direction, the current collector located on one side of the insulating layer away from the active material layer to form a tab.

In a possible implementation manner, a second edge region of the insulating layer covers an end region on one side of the tab close to the insulating layer.

In a possible implementation manner, a thickness of the insulating layer ranges from 1 μm to 25 μm.

In a possible implementation manner, the thickness of the insulating layer ranges from 2 μm to 10 μm.

In a possible implementation manner, in the first direction, a size of the edge portion ranges from 0 to 5 mm.

In a possible implementation, before the coating an active material layer slurry on the current collector, the method further includes: coating a conductive layer slurry on the current collector to form a conductive layer after drying; where the active material layer completely covers the conductive layer.

In a possible implementation manner, in the first direction, a gap is provided between the conductive layer and the insulating layer.

In a possible implementation manner, in the first direction, a size of the gap ranges from 0.1 mm to 4 mm.

In a possible implementation manner, in the first direction, the size of the gap ranges from 0.5 mm to 1 mm.

In a possible implementation manner, a thickness of the conductive layer ranges from 0.5 μm to 2 μm.

In a possible implementation manner, the coating an insulating layer slurry on a current collector to form an insulating layer after drying, includes: coating the insulating layer slurry on the current collector using a micro-gravure coating process, to form the insulating layer after drying.

In the embodiment of the present application, compared with the commonly used die extrusion coating process, the use of micro-gravure coating is beneficial to reducing the thickness of the insulating layer. In this way, the thickness of the insulating layer covering the end region on one side of the tab close to the active material layer is reduced, which makes the tab soft and easier to be bent, and is further beneficial to reducing the space for bending the tab in the process of packaging the battery and increasing the volumetric energy density of the battery.

In a third aspect, an electrode assembly is provided, including: the electrode sheet in the above second aspect or any possible implementation manner of the second aspect.

In a fourth aspect, a battery cell is provided, including: the electrode assembly in the above third aspect or any possible implementation manner of the third aspect; a housing having an opening for accommodating the electrode assembly; and an end cover for closing the opening.

In a fifth aspect, a battery is provided, including: the battery cell in the above fourth aspect or any possible implementation manner of the fourth aspect.

In a sixth aspect, a power consumption device is provided, including: the battery in the fifth aspect or any possible implementation manner of the fifth aspect, the battery being configured to provide electrical energy.

Reference is made to the beneficial effects of the above first aspect for the beneficial effects of the second aspect to the sixth aspect, which will not be repeated redundantly herein.

In the accompanying drawings, the accompanying drawings are not necessarily drawn to actual scale.

DESCRIPTION OF EMBODIMENTS

Implementation manners of the present application will be further described below in detail with reference to the accompanying drawings and embodiments. The detailed description of the following embodiments and the accompanying drawings are used to exemplarily illustrate principles of the present application, but cannot be used to limit the scope of the present application, that is, the present application is not limited to the described embodiments.

In the description of the present application, it should be noted that unless otherwise illustrated, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present application belongs. The terms used are merely for the purpose of describing specific embodiments, but are not intended to limit the present application. The terms “comprising” and “having” and any variations thereof in the specification and the claims of the present application as well as the brief description of the drawings described above are intended to cover non-exclusive inclusions.

In the description of the embodiments of the present application, the technical terms such as “first” and “second” are merely used to distinguish different objects, and shall not be understood as an indication or implication of relative importance or implicit indication of the quantity of indicated technical features, a specific order or primary-secondary relationship.

The phrase “embodiment” mentioned in the present application means that the specific features, structures, or characteristics described with reference to the embodiment may be included in at least one embodiment of the present application. The phrase at various locations in the specification does not necessarily refer to the same embodiment, or an independent or alternative embodiment that is mutually exclusive from another embodiment. Those skilled in the art understand, in explicit and implicit manners, that the embodiments described in the present application may be combined with another embodiment.

In the description of the embodiments of the present application, the term “and/or” is only an association relation describing associated objects, which means that there may be three relations. For example, A and/or B may represent three situations: A exists alone, both A and B exist, and B exists alone. In addition, the character “/” herein generally indicates that the associated objects before and after the character are in an “or” relationship.

In the description of the embodiments of the present application, the term “a plurality of” means two or more (including two). Similarly, “a plurality of groups” means two or more groups (including two groups), and “a plurality of sheets” means two or more sheets (including two sheets).

In the embodiments of the present application, the same reference signs represent the same components, and for the sake of brevity, detailed descriptions of the same components are omitted in different embodiments. It should be understood that the dimensions, such as thickness, length, width, of various components, as well as the dimensions, such as the overall thickness, length and width, of the integrated apparatus in the embodiments of the present application shown in the drawings are only the exemplary description, and should not constitute any limitation to the present application.

In the description of the embodiments of the present application, unless otherwise explicitly specified and defined, the technical terms, such as “installation”, “interconnection” and “connection”, should be understood in a broad sense; for example, they may be either a fixed connection, or a detachable connection, or an integrated connection; they may be a mechanical connection, or an electrical connection; and they may be a direct connection, or an indirect connection via an intermediate medium, or communication between interiors of two elements or the interactive relationship of two elements. Those of ordinary skill in the art may appreciate the specific meanings of the foregoing terms in the present application according to specific conditions.

In the present application, a battery cell may include a lithium-ion secondary battery, a lithium-ion primary battery, a lithium-sulfur battery, a sodium/lithium-ion battery, a sodium-ion battery, a magnesium-ion battery, or the like, which is not limited in the embodiments of the present application. The battery cell may be cylindrical, flat, cuboid or in another shape, which is not limited in the embodiments of the present application. A battery cell is generally divided into three types according to the way of packaging: a cylindrical battery cell, a prismatic battery cell and a pouch battery cell, which is also not limited in the embodiments of the present application.

The battery mentioned in the embodiments of the present application refers to a single physical module including one or more battery cells to provide a higher voltage and capacity. For example, the battery mentioned in the present application may include a battery module, a battery pack, or the like. The battery generally includes a box for packaging one or more battery cells. The box may avoid liquid or other foreign matters to affect charging or discharging of the battery cell.

The battery cell includes an electrode assembly and an electrolytic solution, and the electrode assembly is composed of a positive electrode sheet, a negative electrode sheet and a separator. At present, in order to prevent a short circuit between the positive and negative electrodes and improve the safety of the battery, an insulating material is often coated on the edge of the positive electrode sheet or the negative electrode sheet to form an insulating layer. In the existing battery, the common producing method of an electrode sheet is mainly: extruding a liquid active material layer slurry and insulating layer slurry respectively through extrusion dies and coating them on a current collector using a die extrusion coating process, then drying the current collector coated with the slurries, heating it for volatilizing to remove a solvent, and finally rolling the dried current collector to form an active material layer and an insulating layer on the current collector, so as to obtain a positive electrode sheet or a negative electrode sheet.

However, in the above producing and processing process, there is a gradient difference in surface tension between the active material layer slurry and the insulating layer slurry due to the different materials used by the two, and the gradient difference in tension is more significant due to the difference in drying rate, which leads to the easy migration of the insulating layer slurry to the active material layer slurry, causing coating bulging edge, thereby resulting in a decrease in processing efficiency and processing quality of the electrode sheet to cause poor final quality of the electrode sheet.

In view of this, an embodiment of the present application provides an electrode sheet. In this electrode sheet structure, on a current collector, an edge portion on one side of an active material layer close to an insulating layer covers a first edge region of the insulating layer. That is, the insulating layer is first formed on the current collector by coating and drying, and then the active material layer is formed on the current collector, so that the edge portion of the active material layer covers the first edge region of the insulating layer. This can limit the migration of a liquid insulating layer slurry to the active material layer, which could effectively avoid the problem of coating bulging edge caused by migration of the insulating layer to the active material layer, and be beneficial to improving processing efficiency and processing quality of the electrode sheet and obtaining an electrode sheet with higher final quality. In addition, the edge portion on one side of the active material layer close to the insulating layer covers the first edge region of the insulating layer, that is, there is no directly exposed current collector between the active material layer and the insulating layer. This is beneficial to avoiding the phenomenon of puncturing a separator by generating wrinkles at the exposed current collector due to the effect of stress concentration, and is further beneficial to improving the safety of a battery.

The electrode sheet described in the embodiments of the present application may be a positive electrode sheet or a negative electrode sheet. The electrode sheet described in the embodiments of the present application is applicable to an electrode assembly, a battery cell, a battery, and a power consumption device using a battery.

The power consumption device may be a vehicle, a mobile phone, a portable device, a notebook computer, a ship, a spacecraft, an electric toy, an electric tool, and the like. The vehicle may be a fuel-powered vehicle, a gas-powered vehicle or a new energy vehicle, and the new energy vehicle may be a battery electric vehicle, a hybrid vehicle, an extended-range vehicle, or the like; the spacecraft includes an airplane, a rocket, a space shuttle, a spaceship, and the like; the electric toy includes a fixed or mobile electric toy, such as a game console, an electric vehicle toy, an electric ship toy, and an electric airplane toy; and the electric tool includes an electric metal cutting tool, an electric grinding tool, an electric assembling tool and an electric railway tool, such as an electric drill, an electric grinder, an electric spanner, an electric screwdriver, an electric hammer, an electric impact drill, an concrete vibrator and an electric planer. The above power consumption device is not specially limited in the embodiments of the present application.

For convenience of description, the following embodiments will be explained by an example that the power consumption device is a vehicle.

FIG.1is a schematic structural diagram of a vehicle1provided in an embodiment of present application. As shown inFIG.1, the vehicle1is internally provided with a battery2, and the battery2may be disposed at the bottom, head or tail of the vehicle1. The battery2may be configured to supply power to the vehicle1. For example, the battery2may be used as an operation power supply of the vehicle1.

The vehicle1may further include a controller11and a motor12, and the controller11is configured to control the battery2to supply power to the motor12, for example, for a working power demand of the vehicle1during startup, navigation and running.

In some embodiments of the present application, the battery2may be used not only as an operation power supply of the vehicle1, but also as a driving power supply of the vehicle1, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle1.

FIG.2is a schematic exploded view of a battery2provided in an embodiment of present application. As shown inFIG.2, the battery2includes a box20and a battery cell3, and the battery cell3is accommodated in the box20.

The box20is configured to accommodate the battery cell3. The box20may be a variety of structures. In some embodiments, the box20may include a first box part201and a second box part202, the first box part201and the second box part202are covered with each other, the first box part201and the second box part202jointly define an accommodating space203for accommodating the battery cell3. The second box part202may be a hollow structure with one end open, the first box part201is a plate-like structure, and the first box part201covers the opening side of the second box part202to form the box20having the accommodating space203; or both the first box part201and the second box part202may be hollow structures with one side open, and the opening side of the first box part201covers the opening side of the second box part202to form the box20having the accommodation space203. Certainly, the first box part201and the second box part202may be in various shapes, such as a cylinder, a cuboid.

In order to improve the sealing after the first box part201and the second box part202are connected, a sealing member may be disposed between the first box part201and the second box part202, such as sealant, a sealing ring.

It is assumed that the first box part201covers the top of the second box part202, the first box part201may be referred to as an upper box cover, and the second box part202may be referred to as a lower box.

In the battery2, a plurality of battery cells3are provided. The plurality of battery cells3may be in series connection, parallel connection or series-parallel connection, and the series-parallel connection means that the plurality of battery cells3are connected in series and parallel. The plurality of battery cells3may be in direct series connection, parallel connection or series-parallel connection, and then the whole body composed of the plurality of battery cells3is accommodated in the box20. Certainly, it is also possible that the plurality of battery cells3are in series connection, parallel connection or series-parallel connection first to form a battery module (not shown in the figure), and multiple battery modules are then in series connection, parallel connection or series-parallel connection to form a whole body, which is accommodated in the box20. The plurality of battery cells3in the battery module can be electrically connected through a bus component, so as to realize parallel connection, series connection or series-parallel connection of the plurality of battery cells3in the battery module.

As shown inFIG.3,FIG.3is a schematic structural diagram of a battery cell3according to an embodiment of the present application. The battery cell3includes one or more electrode assemblies31, a housing321, and an end cover322. The housing321and the end cover322form a shell or a battery case32. A wall of the housing321and the end cover322each are referred to as a wall of the battery cell3. For a cuboid battery cell3, walls of the housing321include a bottom wall and four side walls. The housing321is shaped according to a shape of one or more electrode assemblies31after combination. For example, the housing321may be a hollow cuboid or cube or cylinder, and one face of the housing321has an opening, so that the one or more electrode assemblies31can be placed in the housing321. For example, when the housing321is a hollow cuboid or cube, one plane of the housing321is a surface with an opening, that is, the plane does not have a wall, so that the inside and outside of the housing321are in communication with each other. When the housing321may be a hollow cylinder, an end face of the housing321is a surface with an opening, that is, the end face does not have a wall, so that the inside and outside of the housing321are in communication with each other. The end cover322covers the opening and is connected to the housing321to form a closed cavity in which the electrode assemblies31are placed. The housing321is filled with an electrolyte, such as an electrolytic solution.

The battery cell3may further include two electrode terminals33, and the two electrode terminals33can be disposed on the end cover322. The end cover322is generally in a shape of a flat plate, and the two electrode terminals33are fixed on a flat plate face of the end cover322. The two electrode terminals33are a positive electrode terminal331and a negative electrode terminal332, respectively. Each electrode terminal33is correspondingly provided with a connecting member34also called as a current collecting member34, which is located between the end cover322and the electrode assembly31and configured to electrically connect the electrode assembly31to the electrode terminal33.

In the battery cell3, according to actual usage demands, one or more electrode assemblies31may be provided. As shown inFIG.3,4independent electrode assemblies31are disposed in the battery cell3.

The battery cell3may be further provided with a pressure relief mechanism35. The pressure relief mechanism35is configured to be actuated when an internal pressure or temperature of the battery cell3reaches a threshold, to relieve the internal pressure or temperature.

FIG.4is a schematic structural diagram of an electrode sheet311according to an embodiment of present application.FIG.5is a top view of the electrode sheet311inFIG.4.

Referring toFIG.4andFIG.5together, the electrode sheet311may include a current collector36as well as an insulating layer37and an active material layer38located on the current collector36. The active material layer38and the insulating layer37are arranged along a first direction X of the current collector36, and an edge portion381on one side of the active material layer38close to the insulating layer37covers a first edge region371of the insulating layer37.

In the embodiments of the present application, the current collector36refers to a component that collects current. In the battery2, the current collector36mainly refers to metal foil, such as copper foil, aluminum foil. The function of the current collector36is to collect the current newly generated by the active material in the battery2to form larger current output to the outside. Therefore, a metal material with internal resistance as small as possible is generally adopted.

In the embodiments of the present application, the active material layer38refers to the material in the battery2that can participate in a current generating reaction. The current generating reaction is oxidation and reduction reactions. The oxidation reaction refers to a chemical reaction of losing electrons; and the reduction reaction refers to a chemical reaction of gaining electrons. The active material layer38participates in the current generating reaction, that is, the active material on one electrode loses electrons while the active material on the other electrode gains electrons. In the processes of losing and gaining electrons, the electrons generate flow, that is, current.

In the embodiments of the present application, the insulating layer37refers to insulating material, such as aluminum oxide, liquid ceramics.

In the above solution, the edge portion381on one side of the active material layer38on the current collector36close to the insulating layer37covers the first edge region371of the insulating layer37. That is, the insulating layer37is first formed on the current collector36by coating and drying, and then the active material layer38is formed on the current collector36, so that the active material layer38covers the first edge region371of the insulating layer37. This can limit the migration of a liquid insulating layer slurry to the active material layer38, which could effectively avoid the problem of coating bulging edge caused by migration of the insulating layer37to the active material layer38, and be beneficial to improving processing efficiency and processing quality of the electrode sheet311and obtaining an electrode sheet311with higher final quality. In addition, the edge portion381on one side of the active material layer38close to the insulating layer37covers the first edge region371of the insulating layer37, that is, there is no directly exposed current collector36between the active material layer38and the insulating layer37. This is beneficial to avoiding the phenomenon of puncturing a separator by generating wrinkles at the exposed current collector36due to the effect of stress concentration, and is further beneficial to improving the safety of the battery2.

Optionally, in the first direction X, a tab361of the current collector36is located on one side of the insulating layer37away from the active material layer38.

In the above solution, the insulating layer37is located between the tab361and the active material layer38, which is beneficial to ensuring that the edge of the electrode sheet311has good insulation performance, thereby reducing the risk of a short circuit of the battery2and improving the safety performance of the battery2.

Optionally, a second edge region372of the insulating layer37may cover an end region3611on one side of the tab361close to the active material layer38.

In the above solution, the second edge region372of the insulating layer37covers the end region3611on one side of the tab361closes to the active material layer38, which is beneficial to ensuring the insulation of the position of the tab361, so as to be beneficial to ensuring that the edge of the electrode sheet311has good insulation performance after the electrode sheet311is packaged, thereby reducing the risk of a short circuit of the battery2and improving the safety performance of the battery2.

Optionally, a thickness of the insulating layer37ranges from 1 μm to 25 μm, for example, it may be 1 μm, 4 μm, 7 μm, 10 μm, 13 μm, 20 μm, 25 μm, or the like, which is not limited in the present application.

Further, in some embodiments, the thickness of the insulating layer37ranges from 2 μm to 10 μm, for example, it may be 2 μm, 4 μm, 6 μm, 8 μm, 10 μm, or the like, which is not limited in the present application.

In the embodiments of the present application, since the second edge region372of the insulating layer37covers the end region3611of the tab361, the smaller the thickness of the insulating layer37, the more favorable the tab361is to present a soft state, so that the tab361is bent more easily, thereby reducing the space for bending the tab. However, when the thickness of the insulating layer37is too small, for example, when the thickness of the insulating layer37is less than 1 μm, the insulating layer37may not be able to play the role of insulation and protection.

In the above solution, the thickness of the insulating layer37is set reasonably, which is beneficial not only to ensuring that the insulating layer37plays the role of insulation and protection, but also to bending the tab361more easily, thereby reducing the space for bending the tab to improve the volumetric energy density of the battery2.

It should be understood that in the embodiments of the present application, the energy density of the battery2refers to a ratio of the energy that can be charged to the mass or volume of the energy storage medium for a given electrochemical energy storage apparatus. The ratio of the energy that can be charged to the mass of the energy storage medium is mass energy density with a unit of W·h/kg; and the ratio of the energy that can be charged to the volume of the energy storage medium is volumetric energy density with a unit of W·h/L, and the energy storage medium is the active material.

Optionally, in the first direction X, a size of the edge portion381ranges from 0 to 5 mm, for example, it may be 0, 1 cm, 1.5 cm, 2 cm, 3 cm, 3.5 cm, 4 cm, or the like, which is not limited in the present application.

In the embodiments of the present application, the edge portion381on one side of the active material layer38close to the insulating layer37covers the first edge region371of the insulating layer37, which is mainly to ensure that there is no directly exposed current collector36between the active material layer38and the insulating layer37to avoid the phenomenon of puncturing a separator by generating wrinkles at the exposed current collector36due to the effect of stress concentration. However, at the same time, since the edge portion381covers the first edge region371of the insulating layer37, it causes that the active material in this region cannot be used, resulting in a decrease in the energy density of the battery2.

In the above technical solution, the size of the edge portion381of the active material layer38in the first direction X is set to range from 0 to 5 mm, which can ensure that there is no directly exposed current collector36between the active material layer38and the insulating layer37, does not occupy more active material regions, and is beneficial to avoiding the decrease in the energy density of the battery2caused by the unavailability of the active material.

FIG.6is a schematic structural diagram of an electrode sheet311according to another embodiment of present application.

As shown inFIG.6, optionally, the electrode sheet311may further include a conductive layer39. The conductive layer39can be located between the current collector36and the active material layer38, and the active material layer38completely covers the conductive layer39.

In the above solution, the conductive layer39contains a conductive agent and a binder, and thus it has relatively high conductivity and bonding, which is beneficial not only to improving the conductivity of the electrode sheet311and reducing the internal resistance of the battery2, but also to enhancing the adhesion between the active material layer38and the current collector36.

Optionally, in the first direction X, a gap is provided between the conductive layer39and the insulating layer37.

In the above solution, the gap is provided between the conductive layer39and the insulating layer37, which is beneficial to avoiding mutual interference between the insulating layer37and the conductive layer39in the producing process, so as to ensure that the formed conductive layer39and insulating layer37play their respective roles.

Optionally, in the first direction X, a size of the gap between the conductive layer39and the insulating layer37ranges from 0.1 mm to 4 mm, for example, it can be 0.1 mm, 0.5 mm, 1 mm, 1.5 mm, 2 mm, 3 mm, 4 mm, or the like, which is not limited in the present application.

Further, in some embodiments the size of the gap between the conductive layer39and the insulating layer37ranges from 0.5 mm to 1 mm, for example, it can be 0.5 mm, 0.6 mm, 0.7 mm, 0.9 mm, 1 mm, or the like, which is not limited in the present application.

When the gap between the conductive layer39and the insulating layer37is too small, it is unfavorable to avoiding mutual interference between the insulating layer37and the conductive layer39in the producing process. When the gap between the conductive layer39and the insulating layer37is too large, since the gap between the conductive layer39and the insulating layer37is the directly exposed current collector36, and this exposed current collector36is directly covered by the active material layer38and lacks the conductive layer39, thus, it has adverse effects on the internal resistance of the battery2and the adhesion between the active material layer38and the current collector36.

In the above solution, the size of the gap between the conductive layer39and the insulating layer37is set reasonably, which is beneficial not only to avoiding the mutual interference between the conductive layer39and the insulating layer37in the producing process, but also to reducing the adverse effects on the internal resistance of the battery2and the adhesion between the active material layer38and the current collector36since the position of the gap lacks the conductive layer39.

Optionally, a thickness of the conductive layer39ranges from 0.5 μm to 2 μm, for example, it can be 0.5 μm, 1 μm, 1.5 μm, 2 μm, or the like, which is not limited in the present application.

In the embodiments of the present application, when the thickness of the conductive layer39is too small, it is unfavorable to the conductive layer39to play the role. When the thickness of the conductive layer39is too large, it results in the reduction of the overall thickness of the active material layer38, thereby reducing the energy density of the battery2.

In the above solution, the thickness of the conductive layer39is set to range from 0.5 μm to 2 μm, which is beneficial to ensuring that the conductive layer39plays a role in the electrode sheet311without reducing the energy density of the battery2.

The electrode sheet311provided in the embodiments of the present application is described above, a method for producing the electrode sheet311provided in the embodiments of the present application will be described below, and reference can be made to the foregoing various embodiments for the parts that are not described in detail.

FIG.7shows a schematic flowchart of a producing method700of an electrode sheet311according to an embodiment of present application. As shown inFIG.7, the method700includes:

S710: coating an insulating layer slurry on a current collector36to form an insulating layer37after drying; and

S720: coating an active material layer slurry on the current collector36to form an active material layer38after drying, so as to obtain an electrode sheet311.

The active material layer38and the insulating layer37are arranged along a first direction X of the current collector36, and an edge portion381on one side of the active material layer38close to the insulating layer37covers a first edge region371of the insulating layer37.

In the above solution, the insulating layer37is first formed on the current collector36by coating and drying, and then the active material layer38is formed on the current collector36. This can limit the migration of the liquid insulating layer slurry to the active material layer38, which could effectively avoid the problem of coating bulging edge caused by migration of the insulating layer37to the active material layer38, and be beneficial to improving processing efficiency and processing quality of the electrode sheet311and obtaining an electrode sheet311with higher final quality. In addition, the edge portion381on one side of the active material layer38close to the insulating layer37covers the first edge region371of the insulating layer37, that is, there is no directly exposed current collector36between the active material layer38and the insulating layer37. This is beneficial to avoiding the phenomenon of puncturing a separator by generating wrinkles at the exposed current collector36due to the effect of stress concentration, and is further beneficial to improving the safety of the battery2.

Optionally, the insulating layer37may be formed by coating using processes such as die extrusion coating, micro-gravure coating or gravure coating, which is not limited in the present application.

Further, the insulating layer slurry can be coated on the current collector36using a micro-gravure coating process. In this case, step S710may specifically include: coating a liquid insulating layer slurry on the current collector36using a micro-gravure coating process, to form the insulating layer37after drying.

In the above solution, compared with the commonly used die extrusion coating process, the use of micro-gravure coating is beneficial to reducing the thickness of the insulating layer37. In this way, the thickness of the insulating layer37covering the end region3611on one side of the tab361close to the active material layer38is reduced, which makes the tab361soft and easier to be bent, and is further beneficial to reducing the space for bending the tab in the process of packaging the battery2and increasing the volumetric energy density of the battery2.

Optionally, the method700further includes: processing, in the first direction X, the current collector36located on one side of the insulating layer37away from the active material layer38to form a tab361.

Specifically, in the first direction X, the region on one side of the current collector36away from the insulating layer37is a bare foil zone, that is, the directly exposed current collector36, and this exposed current collector36is processed to form the tab361. For example, the current collector36can be cut by laser cutting or mechanical cutting, and the current collector36except the tab361is cut off, so as to form the tab361.

Optionally, a second edge region372of the insulating layer37may cover an end region3611on one side of the tab361close to the active material layer38.

Optionally, before step S720, the method700further includes: coating a conductive layer slurry on the current collector36to form a conductive layer39after drying. The active material layer38completely covers the conductive layer39.

It should be understood that the order of producing the insulating layer37and the conductive layer39on the current collector36is not limited in the embodiments of the present application. For example, the conductive layer slurry and the insulating layer slurry can be coated on the current collector36at the same time according to preset sizes and positions, and the conductive layer39and the insulating layer37are formed after drying. Alternatively, the conductive layer slurry can be coated on the current collector36first to form the conductive layer39, and then the insulating layer slurry is coated to form the insulating layer37. Alternatively, the insulating layer slurry can be coated on the current collector36first to form the insulating layer37, and then the conductive layer slurry is be coated to form the conductive layer39.

Optionally, the conductive layer39and the insulating layer37can use the same coating process or different coating processes, which is not limited in the present application. The conductive layer39can be formed by coating the conductive layer slurry on the current collector36, for example, using a micro-gravure coating process or a gravure coating process.

Optionally, in the first direction X, a gap is provided between the insulating layer37and the conductive layer39. In this way, when the insulating layer slurry and the conductive layer slurry are coated on the current collector36at the same time, mutual interference between the two can be avoided.

An embodiment of the present application further provides an electrode assembly31, which includes the electrode sheet311in the foregoing embodiments.

An embodiment of the present application further provides a battery cell3, which includes the battery assembly31in the foregoing embodiments; a housing321having an opening for accommodating the electrode assembly31; and an end cover322for closing the opening.

An embodiment of the present application further provides a battery2, which includes the battery cell3in the foregoing embodiments.

An embodiment of the present application further provides a power consumption device, which includes the battery2in the foregoing embodiments, the battery2being configured to provide electrical energy.

Although the present application has been described with reference to some embodiments thereof, various modifications can be made thereto without departing from the scope of the present application, and the components therein can be replaced with equivalents. In particular, as long as there is no structural conflict, various technical features mentioned in the various embodiments may be combined in any manner. The present application is not limited to the specific embodiments disclosed herein, and includes all technical solutions falling within the scope of the claims.