Lithium supplement pole piece and preparation method thereof, lubricant, battery and electric equipment

Abstract

The invention relates to a lithium supplement pole piece and a preparation method thereof, a lubricant, a battery and electric equipment, and belongs to the technical field of batteries. The preparation method of the lithium supplement pole piece comprises the steps that an asymmetrical rolling mode is adopted, a lithium material is calendered through a calendering roller, and a lubricating agent is arranged between the lithium material and the calendering roller; covering the calendered lithium material on the surface of the pole piece substrate; the lubricant comprises lubricating oil and inorganic particles dispersed in the lubricating oil. According to the preparation method of the lithium supplement pole piece, the number of binding sites between the calendered lithium film layer and the active material layer of the pole piece substrate is large, so that the binding force between the lithium film layer and the active material layer can be improved; the problems that a traditional lithium film layer and a pole piece base body are difficult to cover, and the binding force between the lithium film layer and an active material layer is poor are solved. The prepared lithium-supplementing pole piece has better wettability to electrolyte, and the battery prepared by adopting the lithium-supplementing pole piece has better cycle performance and better low-temperature resistance.

Description

Technical Field

[0001] The present application relates to the technical field of batteries, and in particular, to a lithium supplement electrode sheet, a preparation method thereof, a lubricant, a battery, and an electrical device. Background Art

[0002] The lithium film layer and the electrode substrate can be laminated to form a lithium supplement electrode sheet to improve the first efficiency and cycle performance of the battery. When the lithium film layer is laminated with the active material layer of the electrode substrate, the bonding force between the lithium film layer and the active material layer of the electrode substrate is poor, and the lamination is relatively difficult. Summary of the Invention

[0003] Aiming at the deficiencies of the prior art, the present application provides a lithium supplement electrode sheet, a preparation method thereof, a lubricant, a battery, and an electrical device to solve the problems that the lamination of the lithium film layer and the electrode substrate is relatively difficult and the bonding force between the lithium film layer and the active material layer of the electrode substrate is poor, and can improve the wettability of the prepared lithium supplement electrode sheet to the electrolyte.

[0004] In a first aspect, the present application provides a preparation method of a lithium supplement electrode sheet. The lithium supplement electrode sheet includes an electrode substrate. The preparation method of the lithium supplement electrode sheet includes: by means of asynchronous rolling, rolling lithium material with a calender roll, and there is a lubricant between the lithium material and the calender roll; laminating the rolled lithium material onto the surface of the electrode substrate; wherein the lubricant includes lubricating oil and inorganic particles dispersed in the lubricating oil.

[0005] In the preparation method of the lithium supplement electrode sheet provided by the present application, the lithium material is placed between two calender rolls, and there is a lubricant between the lithium material and the calender roll, and then the lithium material is rolled. The inorganic particles in the lubricant can increase the friction force between the lithium material and the surface of the calender roll. By means of asynchronous rolling, when the surface linear velocities of the two calender rolls are different, multiple grooves or / and multiple cracks can be formed on the lithium film layer formed by the rolled lithium material; the lubricating oil in the lubricant can facilitate the detachment of the formed lithium film layer from the calender roll, and then facilitate the lamination of the lithium film layer onto the surface of the active material layer of the electrode substrate to form a lithium supplement electrode sheet; and because multiple grooves or / and multiple cracks are formed on the lithium film layer obtained by rolling, when the lithium film layer is laminated with the electrode substrate, there are more bonding sites (mechanical biting sites) between the lithium film layer and the electrode substrate, which can improve the bonding force between the lithium film layer and the active material layer of the electrode substrate, and solve the problems that the traditional lamination of the lithium film layer and the electrode substrate is relatively difficult and the bonding force between the lithium film layer and the active material layer of the electrode substrate is poor.

[0006] The lithium - supplementing electrode sheet prepared by using the preparation method provided by this application has an electrode sheet substrate and a lithium film layer on the surface of the active material layer of the electrode sheet substrate. The lithium film layer has a plurality of grooves and / or a plurality of cracks. The prepared lithium - supplementing electrode sheet has good wettability to the electrolyte. The battery prepared by using this lithium - supplementing electrode sheet has good cycling performance and good low - temperature resistance.

[0007] In some embodiments, the mass ratio of the lubricating oil to the inorganic particles is (30 - 80):(20 - 70). During asynchronous rolling and calendering, when the mass ratio of the lubricating oil to the inorganic particles in the lubricant is within the above - mentioned ratio range, not only can the frictional force between the surface of the lithium material and the surface of the calendering roll be relatively large, making the grooves and / or cracks on the formed lithium film layer after calendering more densely distributed, so that there are more binding sites when the lithium film layer is laminated with the active material layer of the electrode sheet substrate, facilitating the lamination of the lithium film layer and the electrode sheet substrate, but also it is beneficial to improve the binding force between the lithium film layer and the active material layer of the electrode sheet substrate. At the same time, it can also facilitate the relatively uniform coating of the lubricant on the surface of the lithium material and / or the calendering roll and the detachment of the formed lithium film layer from the calendering roll after calendering.

[0008] In some embodiments, the inorganic particles include first particles, and the volume - average particle size D V 50 of the first particles is ≤1 μm. The lubricant contains first particles with a volume - average particle size D V 50 ≤1 μm, which can make the frictional force between the surface of the lithium material and the surface of the calendering roll relatively large, making the grooves and / or cracks on the formed lithium film layer after calendering more densely distributed, so that there are more binding sites when the lithium film layer is laminated with the electrode sheet substrate, facilitating the lamination of the lithium film layer and the electrode sheet substrate, and is beneficial to improving the binding force between the lithium film layer and the active material layer of the electrode sheet substrate.

[0009] In some embodiments, the volume - average particle size D V 50 of the first particles is ≤500 nm. This can make the frictional force between the surface of the lithium material and the surface of the calendering roll more appropriate. It can not only make the grooves and / or cracks on the formed lithium film layer after calendering more densely distributed, but also make the thickness of the formed lithium film layer after calendering thinner, so that there are more binding sites when the formed lithium film layer after calendering is laminated with the electrode sheet substrate, and further facilitate the lamination of the formed lithium film layer after calendering and the electrode sheet substrate, which is beneficial to further improving the binding force between the lithium film layer and the active material layer of the electrode sheet substrate.

[0010] In some embodiments, the first particles are spherical, the inorganic particles further include second particles, the second particles are flaky, and the volume - average particle size D V 50 of the second particles is 1 μm - 20 μm. The lubricant contains second particles with a volume - average particle size D VThe second particle 50 has a size of 1 μm to 20 μm, which can endow the lubricant with a certain viscosity, facilitating the formation of a thin and evenly covered lubricant layer on the surface of the lithium material and / or the working roll. This is beneficial for forming a relatively thin lithium film layer after rolling, and further facilitating the lamination of the lithium film layer with the substrate of the electrode sheet, thereby enhancing the bonding force between the lithium film layer and the active material layer of the substrate of the electrode sheet.

[0011] In some embodiments, the volume average particle size D of the second particle V 50 is 2 μm to 7 μm. The volume average particle size D of the second particle V 50 within the above range can make the viscosity of the lubricant appropriate, enabling the thickness of the lithium film layer formed after rolling to be within a suitable range. This not only facilitates the lamination of the lithium film layer with the substrate of the electrode sheet but also fully exploits the lithium supplement performance of the lithium film layer.

[0012] In some embodiments, the mass ratio of the second particle to the first particle is (1 to 10):1. When the mass ratio of the first particle to the second particle is within the above range, it can balance the viscosity of the lubricant and the frictional force between the lithium material and the surface of the rolling roll during rolling, making both the viscosity of the lubricant and the frictional force between the lithium material and the surface of the rolling roll appropriate. This is not only beneficial for forming a relatively thin lithium film layer after rolling but also facilitates more bonding sites when the lithium film layer formed after rolling is laminated with the substrate of the electrode sheet, further facilitating the lamination of the lithium film layer with the substrate of the electrode sheet and enhancing the bonding force between the lithium film layer and the active material layer of the substrate of the electrode sheet.

[0013] In some embodiments, the viscosity of the lubricant is 10000 mPa·s to 150000 mPa·s. When the viscosity of the lubricant is within the above range, it is beneficial for forming a relatively thin lithium film layer after rolling; especially for the case where the lubricant covers the surface of the lithium material before rolling, when the viscosity of the lubricant is within the above range, it is convenient to form a thin and evenly covered lubricant layer on the surface of the lithium material, which is also beneficial for forming a relatively thin lithium film layer after rolling, and further facilitates the lamination of the lithium film layer with the substrate of the electrode sheet and enhances the bonding force between the lithium film layer and the substrate of the electrode sheet.

[0014] In some embodiments, the viscosity of the lubricant is 30000 mPa·s to 100000 mPa·s. When the viscosity of the lubricant is within the above range, it can make the thickness of the lithium film layer formed after rolling within a suitable range, not only facilitating the lamination of the lithium film layer with the substrate of the electrode sheet but also fully exploiting the lithium supplement performance of the lithium film layer.

[0015] In some embodiments, the inorganic particles contain at least one of carbon element, silicon element, and sulfur element.

[0016] In some embodiments, the material of the inorganic particles is selected from at least one of carbon, silicon and sulfur. The inorganic particles are selected from the above substances, which can increase the friction between the lithium material and the surface of the calendering roller, so that the lithium film layer formed by the calendered lithium material has multiple grooves and / or multiple cracks, which facilitates the lamination of the calendered lithium film layer with the pole piece substrate, and can improve the bonding force between the lithium film layer and the active material layer of the pole piece substrate.

[0017] In some embodiments, the inorganic particles are conductive particles, which is beneficial to improving the electronic conductivity of the lithium-supplementing electrode, and further beneficial to improving the rate performance of the battery prepared using the lithium-supplementing electrode.

[0018] In some embodiments, the lubricant includes at least one of a resin and a hydrocarbon lubricant. The lubricant is selected from the above substances to facilitate the lithium film layer formed after calendering to separate from the calendering roller, and then facilitate the lithium film layer to be coated on the surface of the electrode substrate to form a lithium supplement electrode.

[0019] In some embodiments, the resin is selected from at least one of polyether resin and epoxy resin, so as to facilitate the lithium film layer formed after calendering to separate from the calendering roller, and then facilitate the lithium film layer to be coated on the surface of the electrode substrate to form a lithium supplement electrode.

[0020] In some embodiments, the hydrocarbon lubricant is selected from at least one of poly-alpha-olefin lubricants, white oil and kerosene, so as to facilitate the lithium film layer formed after calendering to separate from the calendering roller, and then facilitate the lithium film layer to be coated on the surface of the electrode substrate to form a lithium supplement electrode.

[0021] In some embodiments, the ratio of the surface linear speeds of the two calendering rollers is (0.03-0.1): 1. This allows the grooves and / or cracks on the lithium film layer formed after calendering to be distributed more densely, so that there are more bonding sites when the lithium film layer formed after calendering is laminated with the pole piece substrate, thereby making it easier for the lithium film layer formed after calendering to laminate with the pole piece substrate, thereby improving the bonding force between the lithium film layer and the active material layer of the pole piece substrate.

[0022] In some embodiments, the surface linear speeds of the two calendering rollers are 1m / min to 50m / min and 2m / min to 100m / min, respectively. When the surface linear speeds of the two calendering rollers are within the above range, not only can the grooves and / or cracks on the lithium film layer formed after calendering be distributed more densely, but also the thickness of the lithium film layer formed after calendering can be within a more appropriate range, which can not only facilitate the lamination of the lithium film layer and the pole piece substrate, but also give full play to the lithium replenishment performance of the lithium film layer.

[0023] In a second aspect, the present application provides a lithium-replenishing pole piece, which includes a pole piece substrate and a lithium film layer located on the surface of the active material layer of the pole piece substrate; wherein the lithium film layer has a plurality of grooves and / or a plurality of cracks.

[0024] In the lithium supplement electrode sheet provided by the present application, there are many binding sites (mechanical biting sites) between the lithium film layer and the active material layer of the electrode sheet substrate, and the binding force between the lithium film layer and the active material layer of the electrode sheet substrate is relatively strong. Since the lithium film layer has a plurality of grooves or / and cracks, the prepared lithium supplement electrode sheet has good wettability with the electrolyte, and the battery prepared by using the lithium supplement electrode sheet has good cycle performance and good low-temperature resistance.

[0025] In some embodiments, the surface of the lithium film layer has a striped pattern formed by grooves or / and cracks, which can make the prepared lithium supplement electrode sheet have good wettability with the electrolyte, and the battery prepared by using the lithium supplement electrode sheet has good cycle performance and good low-temperature resistance.

[0026] In some embodiments, along the direction from the electrode sheet substrate to the lithium film layer, the lithium film layer includes a lithium material layer and a lubricant layer arranged in sequence; wherein, the thickness of the lithium material layer is 1μm to 15μm; the lubricant layer includes a lubricant, and the lubricant includes lubricating oil and inorganic particles dispersed in the lubricating oil. When the thickness of the lithium material layer is within the above range, it is not only convenient for the lithium film layer to be laminated with the electrode sheet substrate, but also can fully exert the lithium supplement performance of the lithium material layer.

[0027] In a third aspect, the present application provides a lubricant, which includes lubricating oil and inorganic particles dispersed in the lubricating oil; the mass ratio of the lubricating oil to the inorganic particles is (30 - 80):(20 - 70).

[0028] Place the lubricant provided by the present application between the surface of the lithium material and two calendering rolls, calender the lithium material, and then laminate the lithium material with the active material layer of the electrode sheet substrate. The inorganic particles in the lubricant can increase the friction force between the lithium material and the surface of the calendering roll. By means of asynchronous rolling, when the surface linear speeds of the two calendering rolls are different, the lithium film layer formed by the calendered lithium material can have a plurality of grooves or / and a plurality of cracks; the lubricating oil in the lubricant can facilitate the separation of the formed lithium film layer from the calendering roll, and further facilitate the lamination of the lithium film layer onto the surface of the active material layer of the electrode sheet substrate to form a lithium supplement electrode sheet; and since the lithium film layer obtained by calendering has a plurality of grooves or / and a plurality of cracks, when the lithium film layer is laminated with the electrode sheet substrate, there are many binding sites (mechanical biting sites) between the lithium film layer and the electrode sheet substrate, which can improve the binding force between the lithium film layer and the active material layer of the electrode sheet substrate, and solve the problems that the traditional lamination of the lithium film layer and the electrode sheet substrate is relatively difficult and the binding force between the lithium film layer and the active material layer of the electrode sheet substrate is not good.

[0029] In addition, the lithium supplement electrode sheet prepared by using the lubricant provided above has an electrode sheet substrate and a lithium film layer on the surface of the active material layer of the electrode sheet substrate, and the lithium film layer has a plurality of grooves and / or cracks. The prepared lithium supplement electrode sheet has good wettability to the electrolyte, and the battery prepared by using the lithium supplement electrode sheet has good cycle performance and good low-temperature resistance.

[0030] In some embodiments, the inorganic particles include first particles, and the volume average particle size D of the first particles V 50≤1 μm. The first particles with a volume average particle size D V 50≤1 μm contained in the lubricant can make the frictional force between the surface of the lithium material and the surface of the calendering roller larger, so that the grooves and / or cracks on the lithium film layer formed after calendering are more densely distributed, so that there are more bonding sites when the lithium film layer is laminated with the electrode sheet substrate, which is convenient for the lithium film layer to be laminated with the electrode sheet substrate, and is beneficial to improving the bonding force between the lithium film layer and the active material layer of the electrode sheet substrate.

[0031] In some embodiments, the volume average particle size D of the first particles V 50≤500 nm. It can make the frictional force between the surface of the lithium material and the surface of the calendering roller more appropriate, which can not only make the grooves and / or cracks on the lithium film layer formed after calendering more densely distributed, but also make the thickness of the lithium film layer formed after calendering thinner at the same time, so that there are more bonding sites when the lithium film layer formed after calendering is laminated with the electrode sheet substrate, and further facilitate the lamination of the lithium film layer formed after calendering with the electrode sheet substrate, which is beneficial to further improving the bonding force between the lithium film layer and the active material layer of the electrode sheet substrate.

[0032] In some embodiments, the first particles are spherical, the inorganic particles further include second particles, the second particles are flaky, and the volume average particle size D of the second particles V 50 is 1 μm to 20 μm. The lubricant contains second particles with a volume average particle size D V 50 of 1 μm to 20 μm, which can endow the lubricant with a certain viscosity, facilitate the formation of a lubricant layer with a relatively thin thickness and uniform coverage on the surface of the lithium material, is beneficial to the formation of a lithium film layer with a relatively thin thickness after calendering, and further facilitates the lamination of the lithium film layer with the electrode sheet substrate, and improves the bonding force between the lithium film layer and the active material layer of the electrode sheet substrate.

[0033] In some embodiments, the mass ratio of the second particles to the first particles is (1 to 10):1. When the mass ratio of the first particles to the second particles is within the above range, the viscosity of the lubricant and the frictional force between the lithium material and the surface of the rolling roller during rolling can be taken into account, so that both the viscosity of the lubricant and the frictional force between the lithium material and the surface of the rolling roller during rolling are appropriate. This is not only conducive to forming a relatively thin lithium film layer after rolling, but also facilitates more bonding sites when the lithium film layer formed after rolling is laminated with the electrode substrate, and further facilitates the lamination of the lithium film layer with the electrode substrate, thereby improving the bonding force between the lithium film layer and the active material layer of the electrode substrate.

[0034] In some embodiments, the viscosity of the lubricant is 10000 mPa·s to 150000 mPa·s; when the viscosity of the lubricant is within the above range, it is conducive to forming a relatively thin lithium film layer after rolling; especially for the case where the lubricant covers the surface of the lithium material before rolling, when the viscosity of the lubricant is within the above range, it is convenient to form a lubricant layer with a relatively thin thickness and uniform coverage on the surface of the lithium material, which is also conducive to forming a relatively thin lithium film layer after rolling, and further facilitates the lamination of the lithium film layer with the electrode substrate, thereby improving the bonding force between the lithium film layer and the electrode substrate.

[0035] Fourthly, the present application provides a battery, which includes the lithium supplement electrode provided in any one of the above second aspects. The battery provided by the present application has high cycle performance and low low-temperature resistance.

[0036] Fifthly, the present application provides an electrical device, which includes the battery provided in the above fourth aspect.

[0037] The above description is only an overview of the technical solution of the present application. In order to understand the technical means of the present application more clearly, it can be implemented according to the content of the specification. In order to make the above and other objects, features, and advantages of the present application more obvious and understandable, the specific embodiments of the present application are specifically exemplified below. Description of the Drawings

[0038] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required to be used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present application, and therefore should not be regarded as limiting the scope. For those of ordinary skill in the art, other related drawings can be obtained based on these drawings without creative efforts.

[0039] Figure 1 It is a schematic structural diagram of a vehicle provided in some embodiments of the present application.

[0040] Figure 2 It is a schematic exploded view of a battery provided in some embodiments of the present application.

[0041] Figure 3 Schematic diagram of the structure of a battery cell provided in some embodiments of the present application.

[0042] Figure 4 Exploded view of the battery cell provided in some embodiments of the present application.

[0043] Figure 5 Cross-sectional view of a lithium supplement electrode sheet with a continuous lithium film layer laminated on a substrate of the electrode sheet.

[0044] Figure 6 Cross-sectional view of the lithium supplement electrode sheet provided in some embodiments of the present application.

[0045] Figure 7 Photo of the lithium film layer prepared in Example 1.

[0046] Figure 8 Photo of the lithium film layer prepared in Comparative Example 1.

[0047] Icons: 1000 - vehicle; 100 - battery; 10 - box; 11 - accommodation space; 12 - first part; 13 - second part; 20 - battery cell; 21 - outer shell; 211 - opening; 22 - end cap assembly; 221 - end cap; 222 - electrode terminal; 23 - electrode assembly; 24 - current collector member; 25 - insulation protection member; 200 - controller; 300 - motor.

[0048] 1 - lithium supplement electrode sheet; 2 - substrate of the electrode sheet; 3 - lithium film layer; 4 - lithium material layer; 5 - lubricating oil layer.

[0049] 400 - lithium supplement electrode sheet; 410 - substrate of the electrode sheet; 420 - lithium film layer; 421 - lithium material layer; 422 - lubricant layer. Detailed implementation manners

[0050] Hereinafter, embodiments of the technical solutions of the present application will be described in detail with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solutions of the present application, and thus are only examples and should not be used to limit the protection scope of the present application.

[0051] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" and any variations thereof in the specification and claims of this application and the above accompanying drawings are intended to cover non-exclusive inclusion.

[0052] In the description of the embodiments of the present application, technical terms such as "first" and "second" are only used to distinguish different objects, and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity, specific order, or primary-secondary relationship of the indicated technical features. In the description of the embodiments of the present application, the meaning of "a plurality of" is more than two, unless otherwise specifically defined.

[0053] Reference to "embodiments" in this text means that the specific features, structures, or characteristics described in connection with the embodiments can be included in at least one embodiment of the present application. The phrase appearing at various positions in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0054] In the description of the embodiments of the present application, the term "and / or" is merely a description of the association relationship of associated objects, indicating that three relationships can exist. For example, A and / or B can represent three situations: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in this text generally represents an "or" relationship between the associated objects before and after.

[0055] In the description of the embodiments of the present application, the orientation or positional relationship indicated by technical terms such as "length", "width", "thickness", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the embodiments of the present application and simplifying the description, rather than indicating or implying that the indicated device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be construed as a limitation on the embodiments of the present application.

[0056] In the description of the embodiments of the present application, unless otherwise clearly specified and limited, technical terms such as "installation", "connection", "fixation", etc. should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can also be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and can be the communication inside two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present application can be understood according to specific circumstances.

[0057] Currently, from the perspective of the development of the market situation, the application of power batteries is becoming more and more extensive. Power batteries are not only applied to energy storage power systems such as hydraulic, thermal, wind, and solar power stations, but also widely used in electric transportation tools such as electric bicycles, electric motorcycles, and electric vehicles, as well as in multiple fields such as military equipment and aerospace. With the continuous expansion of the application fields of power batteries, the market demand for them is also continuously increasing.

[0058] The power battery can be a lithium-ion battery. During the charging process of the lithium-ion battery, lithium ions are removed from the cathode active material, transported through the electrolyte, and pass through the separator to be embedded in the anode active material. To improve the first efficiency and cycle performance of the battery, a lithium supplement electrode is often used in the lithium-ion battery.

[0059] The preparation method of the lithium supplement electrode is as follows: Lubricating oil is coated on the surface of the lithium material, and then the lithium material is placed between two working rollers to roll the lithium material to form a continuous lithium film layer; the continuous lithium film layer obtained after rolling is laminated with the active material layer of the electrode substrate so that the continuous lithium film layer covers and binds to the active material layer of the electrode substrate to form a lithium supplement electrode. However, when the continuous lithium film layer is laminated with the electrode substrate, the binding force between the active material layer of the electrode substrate and the continuous lithium film layer is poor, and there are often difficulties in laminating the continuous lithium film layer with the electrode substrate, and even the situation where the continuous lithium film layer cannot be laminated with the electrode substrate may occur.

[0060] Based on the above considerations, in order to solve the problems of difficult lamination between the lithium film layer and the electrode substrate and poor binding force between the lithium film layer and the active material layer of the electrode substrate, the present application designs a preparation method of a lithium supplement electrode, which includes: adopting an asynchronous rolling method, using a rolling roller to roll the lithium material, and there is a lubricant between the lithium material and the rolling roller; laminating the rolled lithium material on the surface of the electrode substrate; wherein, the lubricant includes lubricating oil and inorganic particles dispersed in the lubricating oil.

[0061] In the preparation method of the lithium supplement electrode provided by the present application, the lithium material is placed between two rolling rollers, and there is a lubricant between the lithium material and the rolling roller, and then the lithium material is rolled. The inorganic particles in the lubricant can increase the friction force between the lithium material and the surface of the rolling roller. By means of the asynchronous rolling method, when the surface linear speeds of the two rolling rollers are different, multiple grooves or / and multiple cracks can be formed on the lithium film layer formed by the rolled lithium material; the lubricating oil in the lubricant can facilitate the detachment of the lithium film layer formed after rolling from the rolling roller, and then facilitate the lamination of the lithium film layer on the surface of the active material layer of the electrode substrate to form a lithium supplement electrode; and because multiple grooves or / and multiple cracks are formed on the lithium film layer obtained by rolling, when the lithium film layer is laminated with the electrode substrate, there are more binding sites (mechanical biting sites) between the lithium film layer and the electrode substrate, which can improve the binding force between the lithium film layer and the active material layer of the electrode substrate, and solve the problems of difficult lamination between the traditional lithium film layer and the electrode substrate and poor binding force between the lithium film layer and the active material layer of the electrode substrate.

[0062] The lithium - supplemented electrode sheet prepared by the preparation method provided in this application has an electrode sheet matrix and a lithium film layer on the surface of the active material layer of the electrode sheet matrix, and the lithium film layer has a plurality of grooves or / and a plurality of cracks. The prepared lithium - supplemented electrode sheet has good wettability with the electrolyte, and the battery prepared by using this lithium - supplemented electrode sheet has good cycle performance and good low - temperature resistance.

[0063] The lithium - supplemented electrode sheet prepared in the above - mentioned manner can be used as a negative electrode sheet. This negative electrode sheet can be assembled with a positive electrode sheet, an electrolyte, and a separator into a battery. The battery can be a battery cell, a module, a battery pack, etc. The battery can be used, but is not limited to, power - consuming devices such as vehicles, ships, or aircraft. A power supply system of the power - consuming device can be composed of a battery disclosed in this application. In this way, it is beneficial to improve the cycle performance and service life of the battery at a relatively high temperature.

[0064] Embodiments of this application provide a power - consuming device using a battery as a power source. The power - consuming device can be a vehicle, a mobile phone, a portable device, a laptop computer, a ship, a spacecraft, an electric toy, an electric tool, etc. The vehicle can be a fuel - powered vehicle, a gas - powered vehicle, or a new - energy vehicle. The new - energy vehicle can be a pure - electric vehicle, a hybrid vehicle, or an extended - range vehicle, etc.; The spacecraft includes an airplane, a rocket, a space shuttle, a spaceship, etc.; The electric toy includes a fixed or mobile electric toy. For example, a game console, an electric vehicle toy, an electric ship toy, an electric airplane toy, etc.; The electric tool includes a metal - cutting electric tool, a grinding electric tool, an assembly electric tool, and a railway - use electric tool. For example, an electric drill, an electric grinding wheel, an electric wrench, an electric screwdriver, a hammer drill, an impact electric drill, a concrete vibrator, and a power planer, etc. Embodiments of this application do not impose special restrictions on the above - mentioned power - consuming devices.

[0065] For the convenience of description, the following embodiments take the power - consuming device as a vehicle as an example for description.

[0066] Please refer to Figure 1 , Figure 1 which is a schematic structural diagram of a vehicle 1000 provided by some embodiments of this application. A battery 100 is arranged inside the vehicle 1000. The battery 100 can be arranged at the bottom, the head, or the tail of the vehicle 1000. The battery 100 can be used for power supply of the vehicle 1000. For example, the battery 100 can be used as an operating power source of the vehicle 1000.

[0067] The vehicle 1000 may further include a controller 200 and a motor 300. The controller 200 is used to control the battery 100 to supply power to the motor 300. For example, it is used for the working power requirements during the start, navigation, and driving of the vehicle 1000.

[0068] In some embodiments of the present application, the battery 100 can not only serve as the operating power source of the vehicle 1000, but also as the driving power source of the vehicle 1000, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000.

[0069] Figure 2 Schematic exploded view of the battery 100 provided for some embodiments of the present application. Please refer to Figure 2 , the battery 100 includes a box body 10 and battery cells 20, and the battery cells 20 are received in the box body 10.

[0070] The box body 10 is used to provide an accommodation space 11 for the battery cells 20. In some embodiments, the box body 10 may include a first part 12 and a second part 13, and the first part 12 and the second part 13 cover each other to define the accommodation space 11 for accommodating the battery cells 20. Of course, the connection between the first part 12 and the second part 13 can be sealed by a sealing member (not shown in the figure), and the sealing member can be a sealing ring, sealant, etc.

[0071] The first part 12 and the second part 13 can be of various shapes, for example, a cuboid, a cylinder, etc. The first part 12 can be a hollow structure with an opening on one side to form an accommodation cavity for accommodating the battery cells 20, and the second part 13 can also be a hollow structure with an opening on one side to form an accommodation cavity for accommodating the battery cells 20. The opening side of the second part 13 covers the opening side of the first part 12, then the box body 10 with the accommodation space 11 is formed. Of course, as Figure 2 shown, it can also be that the first part 12 is a hollow structure with an opening on one side, and the second part 13 is a plate-like structure. The second part 13 covers the opening side of the first part 12, then the box body 10 with the accommodation space 11 is formed.

[0072] In the battery 100, the battery cells 20 can be one or multiple. If there are multiple battery cells 20, the multiple battery cells 20 can be connected in series, parallel or in a mixed connection. A mixed connection means that there are both series and parallel connections among the multiple battery cells 20. The multiple battery cells 20 can be directly connected in series, parallel or in a mixed connection together, and then the whole formed by the multiple battery cells 20 is received in the box body 10; of course, it can also be that multiple battery cells 20 are first connected in series, parallel or in a mixed connection to form battery modules, and then the multiple battery modules are connected in series, parallel or in a mixed connection to form a whole and are received in the box body 10. The battery cells 20 can be in the shape of a cylinder, a flat body, a cuboid or other shapes, etc. Figure 2 An exemplary case where the battery cells 20 are square is shown.

[0073] In some embodiments, the battery 100 may further include a busbar component (not shown in the figure). The multiple battery cells 20 can be electrically connected through the busbar component to achieve series connection, parallel connection, or hybrid connection of the multiple battery cells 20.

[0074] Figure 3 FIG. 4 is a schematic structural diagram of the battery cell 20 provided in some embodiments of the present application. Figure 4 FIG. 5 is an exploded view of the battery cell 20 provided in some embodiments of the present application. Please refer to Figure 3 and Figure 4 , the battery cell 20 may include a housing 21, an end cap assembly 22, and an electrode assembly 23. The housing 21 has an opening 211, the electrode assembly 23 is received in the housing 21, and the end cap assembly 22 is used to seal the opening 211.

[0075] The shape of the housing 21 can be determined according to the specific shape of the electrode assembly 23. For example, if the electrode assembly 23 is a cuboid structure, the housing 21 can be selected as a cuboid structure. Figure 3 and Figure 4 Exemplarily shows the case where the housing 21 and the electrode assembly 23 are square.

[0076] The material of the housing 21 can also be various, such as copper, iron, aluminum, stainless steel, aluminum alloy, etc. The embodiments of the present application do not make special limitations on this.

[0077] The end cap assembly 22 includes an end cap 221 and an electrode terminal 222. The end cap assembly 22 is used to seal the opening 211 of the housing 21 to form a closed installation space (not shown in the figure). The installation space is used to accommodate the electrode assembly 23. The installation space is also used to accommodate an electrolyte, such as an electrolytic solution. The end cap assembly 22 is a component for outputting the electrical energy of the electrode assembly 23. The electrode terminal 222 in the end cap assembly 22 is used to be electrically connected to the electrode assembly 23, that is, the electrode terminal 222 is electrically connected to the tab of the electrode assembly 23. For example, the electrode terminal 222 and the tab are connected through a current collecting member 24 to achieve the electrical connection between the electrode terminal 222 and the tab.

[0078] It should be noted that the opening 211 of the outer shell 21 can be one or two. If the opening 211 of the outer shell 21 is one, the end cap assembly 22 can also be one, and two electrode terminals 222 can be provided in the end cap assembly 22, and the two electrode terminals 222 are respectively used for electrically connecting with the positive electrode tab and the negative electrode tab of the electrode assembly 23. If the opening 211 of the outer shell 21 is two, for example, the two openings 211 are arranged on the opposite sides of the outer shell 21, the end cap assembly 22 can also be two, and the two end cap assemblies 22 are respectively covered at the two openings 211 of the outer shell 21. In this case, the electrode terminal 222 in one end cap assembly 22 can be a positive electrode terminal for electrically connecting with the positive electrode tab of the electrode assembly 23; the electrode terminal 222 in the other end cap assembly 22 can be a negative electrode terminal for electrically connecting with the negative electrode tab of the electrode assembly 23.

[0079] In some embodiments, as Figure 4 shown, the battery cell 20 may further include an insulating protection member 25 fixed to the outer periphery of the electrode assembly 23, and the insulating protection member 25 is used for insulating and isolating the electrode assembly 23 from the outer shell 21. Exemplarily, the insulating protection member 25 is a tape adhered to the outer periphery of the electrode assembly 23. In some embodiments, the number of the electrode assemblies 23 is multiple, and the insulating protection member 25 surrounds the outer peripheries of the multiple electrode assemblies 23 and forms an integral structure of the multiple electrode assemblies 23 to keep the structure of the electrode assembly 23 stable. Among them, the electrode assembly 23 can be a wound electrode assembly or a stacked electrode assembly, and the embodiments of the present application are not limited thereto.

[0080] The electrode assembly 23 includes a positive electrode tab, a negative electrode tab and a separator, and the separator is arranged between the positive electrode tab and the negative electrode tab.

[0081] The present application has no special limitation on the positive electrode tab and the separator.

[0082] The separator can be a PP (polypropylene) porous membrane, a PE (polyethylene) porous membrane, a polyimide porous membrane, and a porous membrane formed by composite of various polymers, etc.

[0083] The positive electrode sheet includes a positive electrode current collector and a positive electrode active layer covering at least one surface in the thickness direction of the positive electrode current collector; the material of the positive electrode current collector may include aluminum foil, aluminum foam, aluminum composite current collector (a current collector with a polymer support layer in the middle and aluminum metal layers on both surfaces of the support layer), nickel foil, nickel foam, etc.; the positive electrode active material in the positive electrode active layer includes one or several mixtures of lithium cobalt oxide, lithium nickel oxide, lithium manganese oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminum oxide, and lithium-containing phosphate with olivine structure, for example, lithium nickel cobalt manganate, lithium nickel cobalt aluminate, lithium cobaltate, lithium iron phosphate, lithium manganate, etc.; the binder in the positive electrode active layer is selected from at least one of polyvinylidene fluoride, polyvinylidene fluoride - hexafluoropropylene copolymer, polyacrylate, sodium carboxymethyl cellulose, styrene-butadiene rubber, polyurethane, ethylene-vinyl acetate copolymer, and ethylene-acrylic acid copolymer; the dispersant in the positive electrode active layer is selected from polyvinylpyrrolidone, etc.; the conductive particles in the positive electrode active layer are selected from at least one of conductive carbon black, acetylene black, Ketjen black, carbon fiber, carbon nanotube, graphene, activated carbon, graphite sheet, graphite particle, and mesophase carbon microsphere.

[0084] The negative electrode sheet uses a lithium-supplementing electrode sheet. In this application, the preparation method of the lithium-supplementing electrode sheet includes: rolling the lithium material by an asynchronous rolling method; then laminating the rolled lithium material on the surface of the active material layer of the electrode substrate; wherein, during rolling, there is a lubricant between the lithium material and the rolling roll; the lubricant includes lubricating oil and inorganic particles dispersed in the lubricating oil.

[0085] Among them, "rolling the lithium material by an asynchronous rolling method" means: placing the lithium material between two working rolls, and when rolling the lithium material, the surface linear velocities of the two working rolls are different.

[0086] "There is a lubricant between the lithium material and the rolling roll" can be achieved through the following three methods; Method 1: Cover the lubricant (such as by coating) on the surface of the lithium material; Method 2: Cover the lubricant (such as by coating) on the surface of the rolling roll; Method 3: Cover the lubricant on the surface of the rolling roll and the surface of the lithium material simultaneously.

[0087] The negative electrode substrate includes: a negative electrode current collector and a negative electrode active layer covering at least one surface in the thickness direction of the negative electrode current collector. Among them, the material of the negative electrode current collector can include aluminum foil, copper foil, copper alloy foil, nickel foil, stainless steel foil, titanium foil, nickel foam, copper foam or a polymer substrate coated with a conductive metal, etc. Among them, the conductive metal includes but is not limited to copper, nickel or titanium, and the material of the polymer substrate includes but is not limited to at least one of polyethylene, polypropylene, ethylene-propylene copolymer, polyethylene terephthalate, polyethylene naphthalate and poly(p-phenylene terephthalamide); the negative electrode active material in the negative electrode active layer includes graphite, coke, etc. The conductive agent in the negative electrode active layer can include but is not limited to carbon materials, metals or conductive polymers, etc. The carbon materials can include at least one of conductive carbon black (Super P), carbon nanotubes (CNTs), carbon nanofibers, natural graphite, artificial graphite, flake graphite, carbon dots or graphene, etc. The metal can include metal powders or metal fibers such as copper, iron, aluminum, etc., and the conductive polymer can include at least one of polythiophene, polypyrrole, polyaniline, polyphenylene and polyphenylene vinylene; the binder in the negative electrode active layer can include but is not limited to at least one of polyvinyl alcohol, sodium polyacrylate, potassium polyacrylate, lithium polyacrylate, polyimide, polyamideimide, hydroxypropyl cellulose, diacetyl cellulose, polyvinyl chloride, carboxylated polyvinyl chloride, polyvinylpyrrolidone, polyethylene, polypropylene, epoxy resin, nylon, styrene-butadiene rubber (SBR), polyvinyl alcohol (PVA), polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), polyvinyl butyral, water-based acrylic resin, carboxymethyl cellulose (CMC) or sodium carboxymethyl cellulose (CMC-Na), etc.

[0088] Figure 5 It is a cross-sectional view of the lithium supplementing electrode 1 in which the continuous lithium film layer 3 is laminated with the negative electrode substrate 2. Figure 6 It is a cross-sectional view of the lithium supplementing electrode 400 provided by some embodiments of the present application.

[0089] In the method for preparing the lithium supplementing electrode provided by the present application, an asynchronous rolling method is adopted to roll the lithium material by using a calender roll, and there is a lubricant between the lithium material and the calender roll; the rolled lithium material is laminated on the surface of the negative electrode substrate 410; among them, the lubricant includes lubricating oil and inorganic particles dispersed in the lubricating oil.

[0090] The lithium material is placed between two calender rolls, and there is a lubricant between the lithium material and the calender roll, and then the lithium material is rolled. The inorganic particles in the lubricant can increase the friction between the lithium material and the surface of the calender roll. By means of asynchronous rolling, when the surface linear speeds of the two calender rolls are different, multiple grooves or / and multiple cracks can be formed on the lithium film layer 420 formed by the rolled lithium material (for example, as Figure 6The shown striped lithium film layer 420 structure, where the lithium film layer 420 includes a lithium material layer 421 and a lubricant layer 422 covering the surface of the lithium material layer 421). The lubricating oil in the lubricant can facilitate the detachment of the formed lithium film layer 420 from the calender roll after calendering, and further facilitate the lamination of the lithium film layer 420 onto the surface of the active material layer of the electrode substrate 410 to form the lithium - supplementing electrode 400.

[0091] Comparison Figure 5 With Figure 6 , in Figure 5 , the lithium film layer 3 is a continuous lithium film layer (including a lithium material layer 4 and a lubricating oil layer 5 covering the surface of the lithium material layer 4), and the entire continuous lithium film layer 3 is laminated with the active material layer of the electrode substrate 2 to form the lithium - supplementing electrode 1. In this application, please refer to Figure 6 , since the calendered lithium film layer 420 is a discontinuous type, when the lithium film layer 420 is laminated with the electrode substrate 410, there are more binding sites (mechanical interlocking sites) between the lithium film layer 420 and the active material layer of the electrode substrate 410, which can improve the binding force between the lithium film layer 420 and the active material layer of the electrode substrate 410, and solve the problems that the lamination of the traditional continuous lithium film layer 420 with the electrode substrate 410 is difficult and the binding force between the lithium film layer 420 and the active material layer of the electrode substrate 410 is poor.

[0092] The lithium - supplementing electrode 400 prepared by the preparation method provided in this application has an electrode substrate 410 and a lithium film layer 420 located on the surface of the active material layer of the electrode substrate 410, and the lithium film layer 420 has a plurality of grooves and / or a plurality of cracks. The prepared lithium - supplementing electrode 400 has good wettability to the electrolyte, and the battery prepared with the lithium - supplementing electrode 400 has good cycle performance and good low - temperature resistance.

[0093] In some embodiments, in the lubricant, the mass ratio of the lubricating oil to the inorganic particles is (30 - 80):(20 - 70). During asynchronous rolling calendering, when the mass ratio of the lubricating oil to the inorganic particles in the lubricant is within the above - mentioned ratio range, not only can the friction force between the lithium material surface and the calender roll surface be larger, making the grooves and / or cracks on the formed lithium film layer more densely distributed, so that there are more binding sites when the lithium film layer is laminated with the active material layer of the electrode substrate, facilitating the lamination of the lithium film layer with the electrode substrate, but also it is beneficial to improve the binding force between the lithium film layer and the active material layer of the electrode substrate. At the same time, it can also facilitate the uniform coating of the lubricant on the surface of the lithium material and / or the calender roll and the detachment of the formed lithium film layer from the calender roll.

[0094] Exemplarily, in the lubricant, the mass ratio of the lubricating oil to the inorganic particles can be any value among 30:70, 40:60, 50:50, 55:45, 60:40, 65:35, 70:30, 75:25, and 80:20 or the range value between any two of them.

[0095] In some embodiments, the inorganic particles include first particles, and the volume average particle size D V 50 ≤ 1 μm.

[0096] The lubricant contains first particles with a volume average particle size D V 50 ≤ 1 μm, which can make the friction force between the surface of the lithium material and the surface of the calender roll larger, so that the grooves and / or cracks on the formed lithium film layer after calendering are more densely distributed, facilitating more bonding sites when the lithium film layer is laminated with the electrode substrate, facilitating the lamination of the lithium film layer with the electrode substrate, and being beneficial to improving the bonding force between the lithium film layer and the active material layer of the electrode substrate.

[0097] Exemplarily, the volume average particle size D V 50 of the first particles can be any value among 1 μm, 800 nm, 600 nm, 500 nm, 450 nm, 300 nm, 150 nm, 100 nm, and 50 nm or the range value between any two of them.

[0098] In some embodiments, the volume average particle size D V 50 ≤ 500 nm. This can make the friction force between the surface of the lithium material and the surface of the calender roll more appropriate, not only making the grooves and / or cracks on the formed lithium film layer after calendering more densely distributed, but also making the thickness of the formed lithium film layer thinner, facilitating more bonding sites when the formed lithium film layer is laminated with the electrode substrate, and further facilitating the lamination of the formed lithium film layer with the electrode substrate, being beneficial to further improving the bonding force between the lithium film layer and the active material layer of the electrode substrate.

[0099] In some embodiments, the first particles are spherical, the inorganic particles further include second particles, the second particles are flaky, and the volume average particle size D V 50 of the second particles is 1 μm to 20 μm.

[0100] Among them, the first particles being spherical means that the first particles can be spherical or quasi-spherical particles.

[0101] The lubricant contains first particles with a volume average particle size D VThe second particle 50 has a size of 1 μm to 20 μm, which can endow the lubricant with a certain viscosity, facilitating the formation of a thin and evenly covered lubricant layer on the surface of the lithium material and / or the working roll. This is conducive to forming a relatively thin lithium film layer after rolling, and further facilitating the lamination of the lithium film layer with the substrate of the electrode sheet, thereby enhancing the bonding force between the lithium film layer and the substrate of the electrode sheet.

[0102] Exemplarily, the volume average particle size D of the second particle V 50 can be any value among 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, 14 μm, 15 μm, 16 μm, 17 μm, 18 μm, 19 μm, and 20 μm, or a range value between any two of them.

[0103] In some embodiments, the volume average particle size D of the second particle V 50 is 2 μm to 7 μm. The volume average particle size D of the flaky particle V When 50 is within the above range, the viscosity of the lubricant can be appropriate, and the thickness of the lithium film layer formed after rolling can be within a suitable range. This can not only facilitate the lamination of the lithium film layer with the substrate of the electrode sheet but also fully utilize the lithium supplement performance of the lithium film layer.

[0104] Exemplarily, the volume average particle size D of the second particle V 50 can be any value among 2 μm, 2.5 μm, 3 μm, 3.5 μm, 4 μm, 4.5 μm, 5 μm, 5.5 μm, 6 μm, 6.5 μm, and 7 μm, or a range value between any two of them.

[0105] In some embodiments, the mass ratio of the second particle to the first particle is (1 - 10):1. When the mass ratio of the first particle to the second particle is within the above range, the viscosity of the lubricant and the friction force between the lithium material and the surface of the rolling roll during rolling can be balanced, making both the viscosity of the lubricant and the friction force between the lithium material and the surface of the rolling roll during rolling appropriate. This is not only conducive to forming a relatively thin lithium film layer after rolling but also makes it easier for the lithium film layer formed after rolling to have more bonding sites when laminated with the substrate of the electrode sheet, thus further facilitating the lamination of the lithium film layer with the substrate of the electrode sheet and enhancing the bonding force between the lithium film layer and the active material layer of the substrate of the electrode sheet.

[0106] Exemplarily, the mass ratio of the second particle to the first particle can be any value among 1:1, 2:1, 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1, and 10:1, or a range value between any two of them.

[0107] In some embodiments, the viscosity of the lubricant is 10000mpa.s to 150000mpa.s. The viscosity of the lubricant is within the above range, which is conducive to forming a relatively thin lithium film layer after calendering; especially for the case where the lubricant covers the surface of the lithium material before calendering, the viscosity of the lubricant is within the above range, which is convenient for forming a thin and uniformly covered lubricant layer on the surface of the lithium material, and is also conducive to forming a relatively thin lithium film layer after calendering, thereby making it easier for the lithium film layer to be laminated with the pole piece substrate, and improving the bonding force between the lithium film layer and the pole piece substrate.

[0108] As an example, the viscosity of the lubricant can be 10000 mpa.s, 15000 mpa.s, 20000 mpa.s, 25000 mpa.s, 30000 mpa.s, 35000 mpa.s, 40000 mpa.s, 45000 mpa.s, 50000 mpa.s, 55000 mpa.s, 60000 mpa.s, 65000 mpa. Any value among 10000mpa.s, 70000mpa.s, 75000mpa.s, 80000mpa.s, 85000mpa.s, 90000mpa.s, 100000mpa.s, 110000mpa.s, 120000mpa.s, 130000mpa.s, 140000mpa.s and 150000mpa.s or any range between two of them.

[0109] In some embodiments, the viscosity of the lubricant is 30000mPa.s to 100000mPa.s. When the viscosity of the lubricant is within the above range, the thickness of the lithium film layer formed after rolling can be within a relatively suitable range, which not only facilitates the lamination of the lithium film layer with the pole piece substrate, but also can give full play to the lithium replenishment performance of the lithium film layer.

[0110] In some embodiments, the inorganic particles contain at least one of carbon, silicon, and sulfur.

[0111] In some embodiments, the material of the inorganic particles is selected from at least one of carbon, silicon and sulfur. The inorganic particles are selected from the above substances, which can increase the friction between the lithium material and the surface of the calendering roller, so that the lithium film layer formed by the calendered lithium material has multiple grooves and / or multiple cracks, which facilitates the lamination of the calendered lithium film layer with the pole piece substrate, and can improve the bonding force between the lithium film layer and the active material layer of the pole piece substrate.

[0112] As an example, the carbon single substance may include at least one of carbon black (Super P), carbon nanotubes (CNTs), carbon nanofibers, natural graphite, artificial graphite, flake graphite, carbon dots, and graphene.

[0113] In some embodiments, the inorganic particles are conductive particles; this is beneficial to improving the electronic conductivity of the lithium supplement electrode sheet, and further beneficial to improving the rate performance of the battery prepared using this lithium supplement electrode sheet.

[0114] In some embodiments, the lubricating oil includes at least one of a resin and a hydrocarbon lubricating oil. Selecting the lubricating oil from the above substances facilitates the detachment of the lithium film layer formed after calendering from the calendering roll, and further facilitates the lamination of the lithium film layer onto the surface of the electrode substrate to form a lithium supplement electrode sheet.

[0115] In some embodiments, the resin is selected from at least one of a polyether resin and an epoxy resin. This facilitates the detachment of the lithium film layer formed after calendering from the calendering roll, and further facilitates the lamination of the lithium film layer onto the surface of the electrode substrate to form a lithium supplement electrode sheet.

[0116] Exemplarily, the polyether resin can be selected from polyoxymethylene or poly(chlorohydrin) ether, etc.; the epoxy resin can be selected from bisphenol A epoxy resin, polyphenolic glycidyl ether epoxy resin, aliphatic glycidyl ether epoxy resin, or glycidyl ether type epoxy resin.

[0117] In some embodiments, the hydrocarbon lubricating oil is selected from at least one of polyalphaolefin lubricating oil, white oil, and kerosene. This facilitates the detachment of the lithium film layer formed after calendering from the calendering roll, and further facilitates the lamination of the lithium film layer onto the surface of the electrode substrate to form a lithium supplement electrode sheet.

[0118] Exemplarily, the polyalphaolefin lubricating oil can be polyalphaolefin (PAO).

[0119] In some embodiments, the calendering step includes: the ratio of the surface linear velocities of the two calendering rolls is (0.03 - 0.1):1. This can make the grooves and / or cracks on the lithium film layer formed after calendering more densely distributed, so that there are more bonding sites when the lithium film layer formed after calendering is laminated with the electrode substrate, and further facilitate the lamination of the lithium film layer formed after calendering with the electrode substrate, improving the bonding force between the active material layer between the lithium film layer and the electrode substrate.

[0120] Among them, the surface linear velocity of the calendering roll refers to: the linear velocity of the mass points on the roll surface of the calendering roll.

[0121] Exemplarily, the ratio of the surface linear velocities of the two calendering rolls can be any value among 0.03:1, 0.035:1, 0.04:1, 0.045:1, 0.05:1, 0.055:1, 0.06:1, 0.065:1, 0.07:1, 0.075:1, 0.08:1, 0.085:1, 0.09:1, 0.095:1, and 0.1:1 or the range value between any two of them.

[0122] In some embodiments, the surface linear velocities of the two calendering rollers are 1 m / min to 50 m / min and 2 m / min to 100 m / min respectively. When the surface linear velocities of the two calendering rollers are within the above ranges, not only can the grooves and / or cracks on the formed lithium film layer after calendering be distributed more densely, but also the thickness of the lithium film layer formed after calendering can be within a more appropriate range, which is not only convenient for the lithium film layer to be laminated with the electrode substrate, but also can fully exert the lithium supplement performance of the lithium film layer.

[0123] Define the two calendering rollers as the first calendering roller and the second calendering roller respectively. Exemplarily, the surface linear velocity of the first calendering roller can be any value among 1 m / min, 5 m / min, 10 m / min, 15 m / min, 20 m / min, 25 m / min, 30 m / min, 35 m / min, 40 m / min, 45 m / min and 50 m / min or the range value between any two of them; the surface linear velocity of the second calendering roller can be any value among 2 m / min, 5 m / min, 10 m / min, 20 m / min, 30 m / min, 40 m / min, 50 m / min, 60 m / min, 70 m / min, 80 m / min, 90 m / min, 95 m / min and 100 m / min or the range value between any two of them.

[0124] This application also provides a lithium-supplemented electrode, as Figure 6 shown, the lithium-supplemented electrode 400 includes an electrode substrate 410 and a lithium film layer 420 located on at least one surface in the thickness direction of the electrode substrate 410; wherein, there are a plurality of grooves and / or a plurality of cracks on the lithium film layer 420.

[0125] In the lithium-supplemented electrode 400 provided by this application, there are more binding sites (mechanical biting sites) between the lithium film layer 420 and the electrode substrate 410, and the binding force between the lithium film layer 420 and the electrode substrate 410 is stronger. Since the lithium film layer 420 has a plurality of grooves and / or a plurality of cracks, the prepared lithium-supplemented electrode 400 has better wettability to the electrolyte, and the battery prepared by using the lithium-supplemented electrode 400 has better cycle performance and better low-temperature resistance.

[0126] In some embodiments, the surface of the lithium film layer 420 has a striped pattern formed by grooves and / or cracks. This can make the prepared lithium-supplemented electrode 400 have better wettability to the electrolyte, and the battery prepared by using the lithium-supplemented electrode 400 has better cycle performance and better low-temperature resistance.

[0127] In some embodiments, along the direction from the electrode substrate 410 to the lithium film layer 420, the lithium film layer 420 includes a lithium material layer 421 and a lubricant layer 422 arranged in sequence; wherein, the thickness of the lithium material layer 421 is 1 μm to 15 μm; the lubricant layer 422 includes a lubricant, and the lubricant includes lubricating oil and inorganic particles dispersed in the lubricating oil. When the thickness of the lithium material layer 421 is within the above range, it is not only convenient for the lithium film layer 420 to be laminated with the electrode substrate 410, but also the lithium supplement performance of the lithium material layer can be fully exerted.

[0128] Exemplarily, the thickness of the lithium material layer 421 can be any value among 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, 14 μm, and 15 μm or a range value between any two of them.

[0129] The present application also provides a lubricant, which includes lubricating oil and inorganic particles dispersed in the lubricating oil; the mass ratio of the lubricating oil to the inorganic particles is (30 - 80):(20 - 70).

[0130] Place the lubricant provided by the present application between the surface of the lithium material and two calendering rollers, calender the lithium material, and then laminate the lithium material with the active material layer of the electrode substrate. The inorganic particles in the lubricant can increase the friction force between the lithium material and the surface of the calendering roller. By means of asynchronous rolling, when the surface linear velocities of the two calendering rollers are different, multiple grooves or / and multiple cracks can be formed on the lithium film layer formed by the calendered lithium material; the lubricating oil in the lubricant can facilitate the detachment of the formed lithium film layer from the calendering roller, and further facilitate the lamination of the lithium film layer onto the surface of the active material layer of the electrode substrate to form a lithium supplement electrode; and because the calendered lithium film layer has multiple grooves or / and multiple cracks, when the lithium film layer is laminated with the electrode substrate, there are more binding sites (mechanical biting sites) between the lithium film layer and the electrode substrate, which can improve the binding force between the lithium film layer and the active material layer of the electrode substrate, and solve the problems that the traditional lamination of the lithium film layer and the electrode substrate is relatively difficult and the binding force between the lithium film layer and the active material layer of the electrode substrate is not good.

[0131] In addition, the lithium supplement electrode prepared with the above-provided lubricant has an electrode substrate and a lithium film layer on the surface of the active material layer of the electrode substrate, and the lithium film layer has multiple grooves or / and cracks. The prepared lithium supplement electrode has good wettability with the electrolyte, and the battery prepared with this lithium supplement electrode has good cycle performance and good low-temperature resistance.

[0132] In some embodiments, the inorganic particles include first particles, and the volume average particle size D of the first particles V 50 ≤ 1 μm. The lubricant contains a volume average particle size D VThe first particles with a volume average particle size D of 50 ≤ 1 μm can result in a relatively large frictional force between the surface of the lithium material and the surface of the calender roll, making the grooves and / or cracks on the lithium film layer formed after calendering more densely distributed. This is convenient for having more bonding sites when the lithium film layer is laminated with the substrate of the electrode sheet, facilitating the lamination of the lithium film layer with the substrate of the electrode sheet, and being beneficial to improving the bonding force between the lithium film layer and the active material layer of the substrate of the electrode sheet.

[0133] In some embodiments, the volume average particle size D of the first particles V is 50 ≤ 500 nm. This can result in a more appropriate frictional force between the surface of the lithium material and the surface of the calender roll. It can not only make the grooves and / or cracks on the lithium film layer formed after calendering more densely distributed, but also make the thickness of the lithium film layer formed after calendering relatively thin at the same time. This is convenient for having more bonding sites when the lithium film layer formed after calendering is laminated with the substrate of the electrode sheet, and further facilitates the lamination of the lithium film layer formed after calendering with the substrate of the electrode sheet, being beneficial to further improving the bonding force between the lithium film layer and the active material layer of the substrate of the electrode sheet.

[0134] In some embodiments, the first particles are spherical, and the inorganic particles further include second particles which are flaky. The volume average particle size D of the second particles V is 1 μm to 20 μm. The lubricant contains second particles with a volume average particle size D of 1 μm to 20 μm, which can endow the lubricant with a certain viscosity, facilitating the formation of a lubricant layer with a relatively thin thickness and uniform coverage on the surface of the lithium material and / or the working roll. This is beneficial to forming a lithium film layer with a relatively thin thickness after calendering, and further facilitating the lamination of the lithium film layer with the substrate of the electrode sheet, and improving the bonding force between the lithium film layer and the active material layer of the substrate of the electrode sheet. V The lubricant contains second particles with a volume average particle size D of 1 μm to 20 μm, which can endow the lubricant with a certain viscosity, facilitating the formation of a lubricant layer with a relatively thin thickness and uniform coverage on the surface of the lithium material and / or the working roll. This is beneficial to forming a lithium film layer with a relatively thin thickness after calendering, and further facilitating the lamination of the lithium film layer with the substrate of the electrode sheet, and improving the bonding force between the lithium film layer and the active material layer of the substrate of the electrode sheet.

[0135] In some embodiments, the mass ratio of the second particles to the first particles is (1 - 10):1. When the mass ratio of the first particles to the second particles is within the above proportion range, it can take into account both the viscosity of the lubricant and the frictional force between the lithium material and the surface of the calender roll during calendering, making both the viscosity of the lubricant and the frictional force between the lithium material and the surface of the calender roll during calendering more appropriate. This is not only beneficial to forming a lithium film layer with a relatively thin thickness after calendering, but also convenient for having more bonding sites when the lithium film layer formed after calendering is laminated with the substrate of the electrode sheet, and further facilitating the lamination of the lithium film layer with the substrate of the electrode sheet, and improving the bonding force between the lithium film layer and the active material layer of the substrate of the electrode sheet.

[0136] In some embodiments, the viscosity of the lubricant is 10,000 mPa·s to 150,000 mPa·s; within the above range of the viscosity of the lubricant, it is beneficial to form a lithium film layer with a relatively thin thickness after calendering; especially for the case where the lubricant covers the surface of the lithium material before calendering, within the above range of the viscosity of the lubricant, it is convenient to form a lubricant layer with a relatively thin thickness and uniform coverage on the surface of the lithium material, and it is also beneficial to form a lithium film layer with a relatively thin thickness after calendering, which is further more convenient for the lithium film layer to be laminated with the electrode substrate and improves the bonding force between the lithium film layer and the electrode substrate.

[0137] Regarding the specific selection, size parameters, ligands, etc. of the lubricating oil and inorganic particles in the lubricant, please refer to the foregoing content and will not be elaborated herein.

[0138] The present application also provides a preparation method of a lubricant, including: mixing a lubricating oil and inorganic particles.

[0139] Among them, regarding the specific selection, size parameters, ligands, etc. of the lubricating oil and inorganic particles in the lubricant, please refer to the foregoing content and will not be elaborated herein.

[0140] In some embodiments, the method of mixing the lubricating oil and inorganic particles adopts stirring mixing or segmented stirring mixing, and the stirring mixing time is 1 - 10 h to make the inorganic particles fully dispersed in the lubricating oil.

[0141] The above-mentioned lithium - supplementing electrode sheet can be used to prepare a battery 100, and the prepared battery 100 has high cycle performance and low low - temperature resistance. The battery 100 can be used as a power source for electrical equipment.

[0142] Next, one or more embodiments will be described in more detail with reference to the following examples. Of course, these examples do not limit the scope of one or more embodiments.

[0143] Experimental Example

[0144] (1) Preparation of a positive electrode sheet:

[0145] Lithium iron phosphate, conductive agent Super P, and binder polyvinylidene fluoride (PVDF) with a mass ratio of 95:3:2 are mixed in a solvent N - methyl - 2 - pyrrolidone (NMP) to form a positive electrode active paste with a solid content of 50 wt%.

[0146] The positive electrode active paste is coated on a current collector aluminum foil (with a thickness of 13 μm), dried at 85°C for 4 h, then cold - pressed, and then trimmed and sliced, and dried at 85°C under vacuum conditions for 4 h to obtain a positive electrode sheet, wherein the thickness of the single - side positive electrode active material layer is 200 μm.

[0147] (2) Preparation of a negative electrode sheet:

[0148] Graphite, conductive agent Super P, and binder polytetrafluoroethylene (PTFE) with a mass ratio of 95:2:3 were mixed in the solvent N-methylpyrrolidone (NMP) to prepare a negative electrode active paste with a solid content of 50 wt%.

[0149] The negative electrode active paste was coated on a current collector copper foil (with a thickness of 8 μm), dried at 85 °C for 4 h, then cold-pressed, followed by trimming and cutting into pieces, and dried in a vacuum at 85 °C for 4 h to obtain the negative electrode sheet substrate; among them, the thickness of the single-sided negative electrode active material layer was 150 μm.

[0150] The lubricant was evenly coated on the two opposite surfaces in the thickness direction of the lithium material with a thickness of 0.8 mm to cover a lubricant layer with a thickness of 2.5 μm on both opposite surfaces of the lithium material. Then the lithium material was placed between the first calender roll and the second calender roll to calender the lithium material to obtain a lithium film layer. Through the rotation of the first calender roll and the second calender roll, the lithium film layer was peeled off from the calender roll and then transferred onto the negative electrode sheet substrate to obtain the negative electrode sheet.

[0151] Among them, for the specific composition and related parameters of the lubricant, please refer to Table 1; for the surface linear velocities of the first calender roll and the second calender roll, please refer to Table 2.

[0152] (3) Preparation of the electrode assembly:

[0153] The separator was made of PP (polypropylene), and the thickness of the separator was 16 μm. The negative electrode sheet, the first separator, the positive electrode sheet, and the second separator were laminated and then wound to form the electrode assembly.

[0154] (4) Preparation of the battery cell:

[0155] The tabs of the electrode assembly were welded, the electrode assembly was placed into the housing, and the electrolyte (the electrolyte was a 1 M lithium hexafluorophosphate solution in EC / DMC (1:1 vol%)) was injected, and then through processes such as vacuum packaging, standing, formation, and shaping, the battery cell was obtained.

[0156] Table 1 Specific composition and related parameters of the lubricant

[0157]

[0158]

[0159] In Table 1, " / " means that there is no corresponding parameter.

[0160] Table 2 Surface linear velocities of the first calender roll and the second calender roll

[0161]

[0162]

[0163] Detect the performance of the negative electrode sheets and battery cells prepared in the detection examples and comparative examples:

[0164] (1) The lamination rate of the lithium film layer and the negative electrode sheet substrate

[0165] The calculation formula for the lamination rate of the lithium film layer and the negative electrode sheet substrate is: M = 1 - (A 1 / A 0 ) × 100%, where A 1 is the mass of the lithium film layer not transferred to the negative electrode sheet substrate, and A 0 is "the total mass of the lithium film layer on the calendering roll before the lithium film layer is transferred to the negative electrode sheet substrate".

[0166] (2) The wettability of the negative electrode sheet to the electrolyte

[0167] Drop 0.5 mL of electrolyte (the electrolyte is a 1M lithium hexafluorophosphate EC / DMC (1:1 vol%) solution) onto the surface of the metallic lithium film of the negative electrode sheets prepared in Examples 1-19 and Comparative Examples 1-4. The metallic lithium film on the surface will gradually undergo a lithium intercalation reaction with the negative electrode active material. Use a CCD camera (100X) to observe the time when the metallic lithium film on the surface is completely fused with the negative electrode active material. When there is no obvious solid metallic lithium on the surface of the negative electrode sheet, record this time as the wetting time of the negative electrode sheet.

[0168] (3) The low-temperature resistance of the battery cell

[0169] At 25°C, first charge the battery cell at a constant current of 0.5C to 3.65V, and discharge the battery cell at a constant current of 0.5C to 2.5V. The discharge capacity this time is the battery cell capacity Cn. Then at -25°C, discharge 0.5Cn of the battery cell's capacitance at a constant current of 1C. At this time, the battery capacitance is 0.5Cn. At the same time, measure the current U and voltage I of the battery cell at this time, and calculate the battery cell resistance DCR = U / I.

[0170] (4) The cycling performance of the battery cell

[0171] At 25°C, first charge the battery cell at a constant current of 0.5C to 3.65V, and discharge the battery cell at a constant current of 0.5C to 2.5V. This is a charge-discharge cycle process, and the discharge capacity this time is the discharge capacity of the first week of cycling. The battery cell is subjected to 200 weeks of cyclic charge-discharge testing in the above manner, and the discharge capacity of the 200th week of cycling is detected, and the capacity retention rate of the battery cell after cycling is calculated by the following formula.

[0172] Capacity retention rate (%) of battery cell after weekly cycling = [Discharge capacity at the 200th cycle / Discharge capacity at the 1st cycle] × 100%.

[0173] Among them, the performance of the negative electrode sheet and the battery cell is shown in Table 3.

[0174] Table 3 Performance of negative electrode sheet and battery cell

[0175]

[0176]

[0177] Figure 7 It is a photo of the lithium film layer prepared in Example 1. Figure 8 It is a photo of the lithium film layer prepared in Comparative Example 1.

[0178] From Figure 7 It can be seen that in the lithium film layer prepared in Example 1, there are stripe gaps on the surface of the lithium film layer, indicating that there are more bonding points between the lithium film layer prepared in Example 1 and the negative electrode sheet substrate, which can make the bonding ability between the lithium film layer and the negative electrode sheet substrate stronger.

[0179] From Figure 8 It can be seen that in the lithium film layer prepared in Comparative Example 1, the surface of the lithium film layer is smooth and there are no stripe gaps, indicating that there are few bonding points between the lithium film layer prepared in Comparative Example 1 and the negative electrode sheet substrate, which will lead to poor bonding ability between the lithium film layer and the negative electrode sheet substrate.

[0180] It can be seen from Table 3 that in the negative electrode sheet prepared in Example 1, the lamination rate of the lithium film layer and the negative electrode sheet substrate can reach 92%, while in the negative electrode sheet prepared in Comparative Example 1, the lamination rate of the lithium film layer and the negative electrode sheet substrate is only 8%; combined with Figure 7 , Figure 8 and Table 3, it can be seen that the solution of Example 1 can enable the lithium film layer to be effectively laminated with the negative electrode sheet substrate, while the solution of Comparative Example 1 cannot enable the lithium film layer to be effectively laminated with the negative electrode sheet substrate; it shows that: by adopting the method of "having a lubricant containing inorganic particles between the lithium material and the calendering roll and calendering the lithium material by asynchronous rolling", the lamination rate between the obtained lithium film layer and the negative electrode sheet substrate can be relatively high.

[0181] As can be seen from Table 3, the lamination rate of the lithium film layer and the negative electrode substrate in the battery cells prepared in Examples 1 to 19 and the capacity retention rate of the battery cells are higher than those in the battery cells prepared in Comparative Examples 1 to 4; the wetting time of the negative electrodes prepared in Examples 1 to 19 is lower than that of the negative electrodes prepared in Comparative Examples 3 to 4, and the low-temperature resistance of the battery cells prepared in Examples 1 to 19 is lower than that of the battery cells prepared in Comparative Examples 3 to 4; it is shown that by adopting the method of "having a lubricant containing inorganic particles between the lithium material and the rolling roller and rolling the lithium material in an asynchronous rolling manner", the lamination rate between the obtained lithium film layer and the negative electrode substrate can be relatively high, the wetting performance of the prepared negative electrode with respect to the electrolyte is good, the capacity retention rate of the prepared battery cell is high and the low-temperature performance is good.

[0182] From the comparison among Examples 1 to 5, it can be seen that the ratio of the mass of the lubricating oil to the "total mass of the spherical particles and the flaky particles" can further affect the lamination rate of the lithium film layer and the negative electrode substrate and the capacity retention rate of the battery cell; when the ratio of the mass of the lubricating oil to the "total mass of the spherical particles and the flaky particles" is (30 - 80):(20 - 70), the lamination rate of the lithium film layer and the negative electrode substrate can be relatively high and the capacity retention rate of the battery cell can be relatively high.

[0183] From the comparison between Example 1 and Examples 6 to 8, it can be seen that the volume average particle size D V 50 of the spherical particles can further affect the lamination rate of the lithium film layer and the negative electrode substrate and the capacity retention rate of the battery cell; when the volume average particle size D V 50 of the spherical particles ≤ 1 μm, it is beneficial to further improve the lamination rate of the lithium film layer and the negative electrode substrate and the capacity retention rate of the battery cell; further, when the volume average particle size D V 50 of the spherical particles ≤ 500 nm, it is beneficial to further improve the lamination rate of the lithium film layer and the negative electrode substrate and the capacity retention rate of the battery cell.

[0184] From the comparison between Example 1 and Examples 9 to 10, it can be seen that the volume average particle size D V 50 of the flaky particles can further affect the lamination rate of the lithium film layer and the negative electrode substrate and the capacity retention rate of the battery cell.

[0185] From the comparison between Example 1 and Examples 11 to 12, it can be seen that when the mass ratio of the lubricating oil in the lubricant is the same, the mass ratio of the spherical particles and the flaky particles being 1:(1 - 10) can both result in a relatively high lamination rate of the lithium film layer and the negative electrode substrate and a relatively high capacity retention rate of the battery cell.

[0186] It can be seen from the comparison between Example 1 and Examples 13 to 15 that the lubricating oil in the lubricant is selected from white oil or PAO, the spherical particles in the lubricant are graphite powder or sulfur powder, and the flaky particles in the lubricant are graphite powder or silicon powder, all of which can result in a relatively high compounding rate of the lithium film layer and the negative electrode substrate and a relatively high capacity retention rate of the battery cell.

[0187] It can be seen from the comparison between Example 1 and Examples 16 to 19 that the ratio of the rotational speed of the first working roll to the rotational speed of the second working roll can further affect the compounding rate of the lithium film layer and the negative electrode substrate and the capacity retention rate of the battery cell; when the ratio of the rotational speed of the first working roll to the rotational speed of the second working roll is (0.03 to 0.1):1, it is beneficial to further improve the compounding rate of the lithium film layer and the negative electrode substrate and the capacity retention rate of the battery cell.

[0188] The embodiments described above are some, but not all, of the embodiments of the present application. The detailed description of the embodiments of the present application is not intended to limit the scope of the present application claimed, but merely represents selected embodiments of the present application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without creative efforts fall within the scope of protection of the present application.

Claims

1. A method for preparing a lithium-supplementing electrode, the lithium-supplementing electrode comprising an electrode substrate, It is characterized in that include: Asynchronous rolling is adopted to roll the lithium material using a rolling roller, with a lubricant between the lithium material and the rolling roller; the rolled lithium material is coated on the surface of the pole piece substrate; Wherein, the lubricant includes lubricating oil and inorganic particles dispersed in the lubricating oil.

2. The preparation method according to claim 1, It is characterized in that The mass ratio of the lubricating oil to the inorganic particles is (30-80):(20-70).

3. The preparation method according to claim 1 or 2, It is characterized in that The inorganic particles include first particles, and the volume average particle diameter D of the first particles V 50≤1 μm; Optionally, the volume average particle size D of the first particles V 50 ≤ 500 nm.

4. The preparation method according to claim 3, It is characterized in that The first particles are spherical, and the inorganic particles further include second particles, the second particles are flaky, and the volume average particle size D V 50 of which is 1 μm to 20 μm; Optionally, the volume average particle size D V 50 of the second particles is 2 μm to 7 μm.

5. The preparation method according to claim 4, It is characterized in that The mass ratio of the second particles to the first particles is (1-10):

1.

6. The preparation method according to claim 1 or 2, It is characterized in that The viscosity of the lubricant is 10000mpa.s to 150000mpa.s; Optionally, the viscosity of the lubricant is 30000mPa.s to 100000mPa.s.

7. The preparation method according to claim 1 or 2, It is characterized in that The inorganic particles contain at least one of carbon, silicon and sulfur; Optionally, the material of the inorganic particles is selected from at least one of carbon, silicon and sulfur; Optionally, the inorganic particles are conductive particles.

8. The preparation method according to claim 1 or 2, It is characterized in that The lubricating oil comprises at least one of a resin and a hydrocarbon lubricating oil; Optionally, the resin is selected from at least one of a polyether resin and an epoxy resin; Optionally, the hydrocarbon lubricant is at least one of poly-α-olefin lubricant, white oil and kerosene.

9. The preparation method according to claim 1 or 2, It is characterized in that The ratio of the surface linear speeds of the two calendering rollers is (0.03-0.1):1; Optionally, the surface linear speeds of the two calendering rollers are 1 m / min to 50 m / min and 2 m / min to 100 m / min, respectively.

10. A lithium-replenishing electrode, It is characterized in that The lithium supplement pole piece comprises a pole piece substrate and a lithium film layer located on the surface of the active material layer of the pole piece substrate; Wherein, the lithium film layer has a plurality of grooves and / or a plurality of cracks.

11. The lithium supplement electrode according to claim 10, It is characterized in that The surface of the lithium film layer has a stripe pattern formed by the grooves and / or the cracks.

12. The lithium supplement electrode according to claim 10 or 11, It is characterized in that Along the direction from the pole piece substrate to the lithium film layer, the lithium film layer includes a lithium material layer and a lubricant layer arranged in sequence; wherein the thickness of the lithium material layer is 1 μm to 15 μm; the lubricant layer includes a lubricant, and the lubricant includes lubricating oil and inorganic particles dispersed in the lubricating oil.

13. A lubricant, It is characterized in that The lubricant includes lubricating oil and inorganic particles dispersed in the lubricating oil; The mass ratio of the lubricating oil to the inorganic particles is (30 - 80):(20 - 70).

14. The lubricant according to claim 13, wherein, The inorganic particles include first particles, and the volume average particle diameter D of the first particles V 50 ≤ 1 μm; Optionally, the volume average particle size D of the first particles V 50 ≤ 500 nm; Optionally, the first particles are spherical, the inorganic particles further include second particles, the second particles are flaky, and the volume average particle size D V 50 of the second particles is 1 μm to 20 μm; optionally, the mass ratio of the second particles to the first particles is (1 - 10):1; optionally, the viscosity of the lubricant is 10000 mpa.s - 150000 mpa.s.

15. A battery, wherein, the battery includes a lithium supplement electrode sheet as described in any one of claims 10 - 12.

16. An electrical device, wherein, the electrical device includes the battery according to claim 15.

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