Patent Description:
At present, lithium-ion batteries are widely used in the fields of electric vehicles, consumer electronics, etc., because of their advantages such as high energy density and long service life. During the initial charge of a lithium-ion battery, some lithium will be consumed due to the formation of an SEI film (i.e., a solid electrolyte interface film), which will lead to the loss of lithium in a positive electrode material, reduce the battery capacity, and eventually reduce the efficiency of initial charge. In order to reduce the irreversible reduction of the battery capacity during the initial charge of the battery, in the industry, a prelithiation device is generally used to coat a surface of a substrate with lithium. Therefore, a prelithiation process is very important. Document <CIT>, which forms the basis for the preamble of claim <NUM>, discloses a prelithiation device for bonding a lithium ribbon to a substrate. The device comprises a coating mechanism for coating the two opposite surfaces of a lithium ribbon with a release agent.

An objective of the present application is to provide a prelithiation device and a prelithiation method. The prelithiation device can prevent a lithium ribbon from sticking to a roller to improve the production safety.

The present application is achieved by the following technical solutions.

In one aspect, the present application provides a prelithiation device for bonding a lithium ribbon to a substrate, the prelithiation device comprising: a bonding mechanism comprising a first roller, a second roller and a third roller, which are sequentially disposed adjacent to each other, the first roller and the second roller being used to roll the lithium ribbon, with the rolled lithium ribbon adhering to the second roller, and the second roller and the third roller being used to bond the lithium ribbon adhering to the second roller to the substrate, the lithium ribbon comprising two first surfaces opposite each other in a width direction of the lithium ribbon and a second surface facing the second roller; and a coating mechanism disposed upstream of the bonding mechanism in a running direction of the lithium ribbon and configured to simultaneously coat the second surface and at least one of the first surfaces with a release agent.

In the prelithiation device according to the embodiment of the present application, the second surface and the first surface of the lithium ribbon are simultaneously coated with the release agent by means of the coating mechanism, and the release agent on the second surface and the first surface is diffused as the lithium ribbon extends, so that the release agent is provided on the extended portions of the lithium ribbon, and when the lithium ribbon rotates with the second roller to be between the third roller and the second roller, the lithium ribbon can be separated from the second roller to bond to the substrate, thus preventing the lithium ribbon from sticking to the roller, thereby improving the production safety.

According to some embodiments of the present application, the coating mechanism comprises a coating roller, with a roller face of the coating roller being provided with a recess for accommodating the lithium ribbon, the recess being configured to simultaneously coat the second surface and at least one of the first surfaces with the release agent.

In the above implementations, since the recess can accommodate the lithium ribbon, the cooperation of the recess and the lithium ribbon facilitates simultaneous coating of the second surface and the first surface with the release agent by means of the recess.

According to some embodiments of the present application, the recess is an annular recess disposed around the axis of the coating roller.

In the above implementations, when the coating roller rotates, the second surface and the first surface of the lithium ribbon are continuously coated with the release agent by means of the annular recess, thereby improving the coating efficiency.

According to some embodiments of the present application, the recess comprises a bottom face and two first side faces opposite each other in an axial direction of the coating roller, the bottom face being configured to coat the second surface with the release agent, and the two first side faces being configured to coat the two first surfaces with the release agent.

In the above implementations, the second surface and the two first surfaces of the lithium ribbon are simultaneously coated with the release agent by means of the bottom face and the two first side faces, which can ensure the coating effect and achieve high coating efficiency.

According to some embodiments of the present application, an included angle is formed between each of the first side faces and the bottom face, and the included angle is an obtuse angle.

In the above implementations, the inclined arrangement of the first side faces and the bottom face enables the first surfaces of the lithium ribbon to be coated with more release agent, so as to ensure that sufficient release agent is provided on the extended portions of the lithium ribbon after the lithium ribbon is rolled.

According to some embodiments of the present application, the coating mechanism further comprises a fixed roller, at least a part of the fixed roller being inserted in the recess and forming a gap with the recess, and the fixed roller being used to control the thickness of the release agent adhering to the coating roller.

In the above implementations, the cooperation of the fixed roller and the recess enables the fixed roller to scrape off the extra-thick part of the release agent on the coating roller, so as to control the thickness of the release agent on the coating roller to ensure that the thickness of the release agent adhering to the surface of the lithium ribbon is consistent.

According to some embodiments of the present application, a roller face of the fixed roller is provided with a boss that is inserted in the recess and forms a gap with the recess.

In the above implementations, the thickness of the release agent adhering to the coating roller is controlled by means of the gap between the boss and the recess, and the structure is simple.

According to some embodiments of the present application, the boss is an annular boss disposed around the axis of the fixed roller.

In the above implementations, the boss is disposed around the axis of the fixed roller, so as to facilitate machining.

According to some embodiments of the present application, a notch is formed in the boss to control the thickness of the release agent on the coating roller.

In the above implementations, a fixed roller scraper is easily formed at the notch, so as to control the thickness of the release agent on the coating roller.

According to some embodiments of the present application, the fixed roller is located on the side of the coating roller that is away from the lithium ribbon.

In the above implementations, the fixed roller is located on the side of the coating roller that is away from the lithium ribbon, so as to achieve the rational utilization of the installation space to avoid affecting the running of the lithium ribbon.

According to some embodiments of the present application, the coating mechanism further comprises a release agent squeezing mechanism for squeezing the release agent to a position between the coating roller and the fixed roller.

In the above implementations, the release agent squeezing mechanism squeezes the release agent to a position between the coating roller and the fixed roller so as to supply the release agent for the coating roller.

According to some embodiments of the present application, the coating mechanism further comprises a support roller, the lithium ribbon passing between the support roller and the coating roller.

In the above implementations, the support roller can support the lithium ribbon, so as to facilitate the cooperation of the lithium ribbon and the coating roller to ensure that the release agent uniformly adheres to the surface of the lithium ribbon.

In another aspect, an embodiment of the present application further provides a prelithiation method for bonding a lithium ribbon to a substrate, the prelithiation method comprising: feeding the lithium ribbon between a first roller and a second roller, and rolling the lithium ribbon by means of the first roller and the second roller, with the rolled lithium ribbon adhering to the second roller, and the lithium ribbon comprising two first surfaces opposite each other in a width direction of the lithium ribbon and a second surface facing the second roller; feeding the substrate between the second roller and a third roller to bond the lithium ribbon adhering to the second roller to the substrate by means of the second roller and the third roller; and coating the second surface and at least one of the first surfaces with a release agent, by means of a coating mechanism, in a running direction of the lithium ribbon and upstream of the first roller and the second roller.

The prelithiation method according to the embodiment of the present application can implement coating of the first surface of the lithium ribbon with the release agent, and avoid the sticking of the lithium ribbon to the roller in a prelithiation process, thereby improving the prelithiation production safety.

Some of the additional aspects and advantages of the present application will be set forth in the following description, and some will become apparent from the following description, or be learned by practice of the present application.

In order to more clearly describe the technical solutions of the embodiments of the present application, the accompanying drawings required in the embodiments will be described briefly below. It should be understood that the following accompanying drawings illustrate only some embodiments of the present application and therefore should not be construed as a limitation on the scope thereof. For those of ordinary skill in the art, other relevant accompanying drawings can also be obtained from these accompanying drawings without any creative effort.

In the accompanying drawings, the figures are not drawn to scale.

List of reference numerals: <NUM> - bonding mechanism; <NUM> - first roller; <NUM> - second roller; <NUM> - third roller; <NUM> - fourth roller; <NUM> - coating mechanism; <NUM> - coating roller; <NUM> - recess; <NUM> - first side face; <NUM> - bottom face; α - included angle; <NUM> - fixed roller; <NUM> - boss; <NUM> - notch; <NUM> - fixed roller scraper; <NUM> - support roller; <NUM> - nozzle; <NUM> - accommodating recess; <NUM> - lithium ribbon conveying mechanism; <NUM> - lithium ribbon unwinding roller; <NUM> - substrate conveying mechanism; <NUM> - substrate unwinding roller; <NUM> - substrate winding roller; <NUM> - prepressing mechanism; <NUM> - prepressing roller; <NUM> - traction roller; <NUM> - traction belt; <NUM> - cleaning mechanism; <NUM> - cleaning scraper; <NUM> - cleaning brush; <NUM> - dust collection assembly; L - lithium ribbon; L1 - first surface; L2 - second surface; L3 - third surface; and P - substrate.

In order to make the objectives, technical solutions and advantages of embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the embodiments described are some of, rather than all of, the embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those of ordinary skill in the art without any creative effort fall within the scope of protection of the present application.

Unless otherwise defined, all technical and scientific terms used in the present application have the same meanings as those commonly understood by those skilled in the art to which the present application belongs; the terms used in the description of the present application are merely for the purpose of describing specific embodiments, but are not intended to limit the present application. The terms "comprising" and "having" and any variations thereof in the description and the claims of the present application as well as the brief description of the accompanying drawings described above are intended to cover non-exclusive inclusion. The terms "first", "second", etc. in the description and the claims of the present application as well as the foregoing accompanying drawings are used to distinguish between different objects, rather than describing a specific order or a primary-secondary relationship.

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

In the description of the present application, it should be noted that, the terms "mount", "connected", "connect", or "attach" should be interpreted in a broad sense unless explicitly defined and limited otherwise. For example, they may be a fixed connection, a detachable connection, or an integral connection; or may be a direct connection, an indirect connection by means of an intermediate medium, or internal communication between two elements. For those of ordinary skills in the art, the specific meaning of the foregoing terms in the present application may be understood according to specific circumstances.

The term "and/or" in the present application is merely a description of the associated relationship of associated objects, representing that three relationships may exist, for example, A and/or B, may be expressed as: the three instances of A alone, A and B simultaneously, and B alone. In addition, the character "/" in the present application generally indicates that the associated objects before and after the character are in a relationship of "or".

In the present application, "a plurality of" means two or more (including two), and similarly, "a plurality of groups" means two or more groups (including two groups), and "a plurality of pieces" means two or more pieces (including two pieces).

A battery mentioned in the present application refers to a single physical module including one or more battery cells to provide a higher voltage and capacity. For example, the battery mentioned in the present application may comprise a battery module, a battery pack, etc..

The core member of a lithium-ion battery that can implement the repeated charge and discharge function is an electrode assembly in a battery cell. The electrode assembly comprises a positive electrode plate, a negative electrode plate, and a separator. The lithium-ion battery operates mainly by the movement of lithium ions between the positive electrode plate and the negative electrode plate.

The positive electrode plate comprises a positive electrode current collector and a positive electrode active material layer applied to a surface of the positive electrode current collector, and the current collector not coated with the positive electrode active material layer protrudes from the current collector coated with the positive electrode active material layer and serves as a positive electrode tab. Generally, in the lithium-ion battery, the positive electrode current collector may be aluminum foil, and the positive electrode active material layer may be ternary lithium, lithium manganate, lithium cobaltate or lithium iron phosphate, etc..

The negative electrode plate comprises a negative electrode current collector and a negative electrode active material layer applied to a surface of the negative electrode current collector, and the current collector not coated with the negative electrode active material layer protrudes from the current collector coated with the negative electrode active material layer and serves as a negative electrode tab. Generally, in the lithium-ion battery, the negative electrode current collector may be copper foil, and the negative electrode active material layer may be carbon or silicon, etc..

The lithium-ion battery forms a solid electrolyte interface film during the initial charge and discharge process, and the solid electrolyte interface film will consume some lithium, resulting in the loss of lithium and thus leading to a capacity loss of the lithium-ion battery. In order to compensate for the loss of active lithium during the initial charge and discharge process of the lithium-ion battery, it is desired to supplement active lithium onto the active material layer of the electrode plate in advance during forming of the electrode plate. At present, a prelithiation device is generally used to coat the surface of the electrode plate with lithium to reduce the irreversible decrease in capacity of the lithium-ion battery during the initial charge process and thus improve the capacity and cycle life of the lithium-ion battery.

The electrode plate prelithiation device may be used for prelithiation on the electrode plate to improve the capacity and cycle life of the lithium-ion battery. The substrate mentioned in the embodiments of the present application may be metal foil, i.e., a current collector, or may be an electrode plate provided with an active material layer.

A prelithiation process for the substrate mainly comprises a rolling process and a bonding process. In the rolling process, a lithium ribbon is thinned by pressing to form a lithium film; and in the bonding process, the lithium film is bonded to the surface of the substrate by rolling. It should be noted that for ease of subsequent description, the lithium film in the practical sense is also named after the lithium ribbon.

In the prior art, the prelithiation device rolls the lithium ribbon by means of a bonding mechanism and bonds the rolled lithium ribbon to the substrate, and potential safety hazards such as smoking and fire often occur during prelithiation.

The inventor has found that the main reason for smoking and fire is that the lithium ribbon sticks to a roller, and the sticking of the lithium ribbon to the roller is mainly due to the adhesion of an edge portion of the lithium ribbon to the roller. It has been found through further research that after the lithium ribbon is rolled, the lithium ribbon extends in a width direction, but since no release agent is provided on extended portions of the lithium ribbon, the adhesive force between the extended portions of the lithium ribbon and the roller face of the roller is greater than that between the lithium ribbon and the substrate during bonding, so that the extended portions of the lithium ribbon still adhere to the roller face of the roller to cause sticking to the roller, resulting in potential safety hazards such as smoking and fire.

In view of this, the present application provides a prelithiation device comprising a bonding mechanism and a coating mechanism. The bonding mechanism comprises a first roller, a second roller and a third roller, which are sequentially disposed adjacent to each other, and the coating mechanism is disposed upstream of the bonding mechanism. A second surface of a lithium ribbon facing the second roller and at least one of first surfaces of the lithium ribbon in a width direction are simultaneously coated with a release agent by means of the coating mechanism, and the release agent on the second surface and the first surface is diffused as the lithium ribbon extends, so that the release agent is provided on the extended portions of the lithium ribbon; and when the lithium ribbon rotates with the second roller to locate between the third roller and the second roller, the lithium ribbon can be separated from the second roller and bonded to the substrate, thus preventing the lithium ribbon from sticking to the roller, thereby improving the production safety.

<FIG> shows a schematic structural diagram of a prelithiation device according to an embodiment of the present application; and <FIG> shows a schematic diagram of the principle of a prelithiation process according to an embodiment of the present application. As shown in <FIG>, the prelithiation device comprises a bonding mechanism <NUM> and a coating mechanism <NUM>.

The bonding mechanism <NUM> comprising a first roller <NUM>, a second roller <NUM> and a third roller <NUM>, which are sequentially provided adjacent to each other. As shown in <FIG>, the first roller <NUM> and the second roller <NUM> are used to roll a lithium ribbon L, and the rolled lithium ribbon L adheres to the second roller <NUM>, so as to implement a rolling process. The second roller <NUM> and the third roller <NUM> are used to bond the lithium ribbon L adhering to the second roller <NUM> to a substrate P to implement a bonding process.

The first roller <NUM>, the second roller <NUM> and the third roller <NUM> are parallel to each other, that is, have axes thereof parallel to each other.

The first roller <NUM> and the second roller <NUM> are disposed opposite each other, a roller gap between the first roller <NUM> and the second roller <NUM> is used for the lithium ribbon L to pass through, and the first roller <NUM> and the second roller <NUM> cooperate to achieve a rolling function. The second roller <NUM> and the third roller <NUM> are disposed opposite each other, a roller gap between the second roller <NUM> and the third roller <NUM> is used for the substrate P to pass through, and the second roller <NUM> and the third roller <NUM> cooperate to achieve a bonding function.

It should be noted that the arrangement of the first roller <NUM>, the second roller <NUM> and the third roller <NUM> is not limited. For example, the first roller <NUM>, the second roller <NUM> and the third roller <NUM> may be sequentially arranged in a horizontal direction, or the first roller <NUM>, the second roller <NUM> and the third roller <NUM> may be sequentially arranged in a vertical direction, or the first roller <NUM>, the second roller <NUM> and the third roller <NUM> may be arranged in an L-shape. The specific arrangement of the first roller <NUM>, the second roller <NUM> and the third roller <NUM> can be determined according to the operating condition requirements matched for the prelithiation device. In this embodiment, the arrangement of the first roller <NUM>, the second roller <NUM> and the third roller <NUM> is not limited. In this embodiment, only the example in which the first roller <NUM>, the second roller <NUM> and the third roller <NUM> are sequentially arranged in the horizontal direction is taken as an example for description.

The lithium ribbon L comprises two first surfaces L1 (see <FIG>) opposite each other in a width direction of the lithium ribbon L and a second surface L2 facing the second roller <NUM>, the width direction of the lithium ribbon L being parallel to an axial direction of the second roller <NUM>, i.e., the first surfaces L1 are narrow side faces of the lithium ribbon L.

The lithium ribbon L has certain plasticity. When the lithium ribbon L is fed between the first roller <NUM> and the second roller <NUM>, since the roller gap between the first roller <NUM> and the second roller <NUM> is smaller than the thickness of the lithium ribbon L, the lithium ribbon is pressed to extend in the width direction and form a film-like structure with a certain thickness, which is conductive to bonding to the surface of the substrate P in a subsequent bonding process.

As shown in <FIG>, the coating mechanism <NUM> is disposed upstream of the bonding mechanism <NUM> in a running direction of the lithium ribbon L, and the coating mechanism <NUM> is configured to simultaneously coat the second surface L2 and at least one of the first surfaces L1 with a release agent.

It should be noted that upstream and downstream are the sequence in the process for machining the lithium ribbon L, regardless of a spatial position. For example, the coating mechanism <NUM> being located upstream of the bonding mechanism <NUM> means that the lithium ribbon L is first coated with the release agent by the coating mechanism <NUM>, then subjected to a rolling and bonding process by means of the bonding mechanism <NUM>, and finally bonded to the substrate P.

In the prelithiation device according to the embodiment of the present application, as shown in <FIG>, the second surface L2 and the first surface L1 are simultaneously coated with the release agent by means of the coating mechanism <NUM>, and the release agent on the second surface L2 and the first surface L1 is diffused as the lithium ribbon L extends, so that the release agent is provided on extended portions of the lithium ribbon L, and when the lithium ribbon L rotates with the second roller <NUM> to be between the third roller <NUM> and the second roller <NUM>, since the lithium ribbon L is coated with the release agent, the lithium ribbon L can be transferred from the second roller <NUM> and bonded to the substrate P, and the lithium ribbon L is not likely to adhere to the second roller <NUM>, thus alleviating the problems such as smoking and fire caused by sticking of the lithium ribbon L to the roller, thereby improving the production safety.

It should be noted that the coating mechanism <NUM> may coat only one first surface L1 of the lithium ribbon L with the release agent, or may coat both the first surfaces L1 of the lithium ribbon L with the release agent. When the coating mechanism <NUM> coats only one first surface L1 of the lithium ribbon L with the release agent, in order to ensure that both the first surfaces L1 of the lithium ribbon L can be coated with the release agent, the prelithiation device is provided with a further coating mechanism, and the two coating mechanisms respectively coat the two first surfaces L1 of the lithium ribbon L in the width direction with the release agent. In order to ensure the uniform coating of the surface of the lithium ribbon L with the release agent, the coating mechanism <NUM> of the embodiment of the present application can simultaneously coat the second surface L2 and the two first surfaces L1 of the lithium ribbon L with the release agent.

<FIG> shows a schematic structural diagram of a coating roller <NUM> according to an embodiment of the present application; and <FIG> shows a schematic structural diagram of a coating mechanism <NUM> according to an embodiment of the present application.

According to some embodiments of the present application, as shown in <FIG> and <FIG>, the coating mechanism <NUM> comprises a coating roller <NUM>, with a roller face of the coating roller <NUM> being provided with a recess <NUM> for accommodating the lithium ribbon L, the recess <NUM> being configured to simultaneously coat the second surface L2 and at least one of the first surfaces L1 with the release agent. Since the recess <NUM> can accommodate the lithium ribbon L, the recess <NUM> coats the lithium ribbon L with the release agent in such a manner that, when the lithium ribbon L passes through the recess <NUM>, the release agent adhering to the recess face of the recess <NUM> adheres to both the first surface L1 and the second surface L2 of the lithium ribbon L.

According to some embodiments of the present application, the recess <NUM> is an annular recess disposed around the axis of the coating roller <NUM>. When the coating roller <NUM> rotates, the first surface L1 and the second surface L2 of the lithium ribbon L are continuously coated with the release agent by means of the annular recess <NUM>, thus improving coating efficiency.

According to some embodiments of the present application, as shown in <FIG> and <FIG>, the recess <NUM> comprises a bottom face <NUM> and two first side faces <NUM> opposite each other in an axial direction of the coating roller <NUM>, the bottom face <NUM> being configured to coat the second surface L2 with a release agent, and the two first side faces <NUM> being configured to coat the two first surfaces L1 with a release agent. The bottom face <NUM> and the two first side faces <NUM> are both recess faces of the recess <NUM>. The bottom face <NUM> is connected to the two first side faces <NUM> so as to accommodate the lithium ribbon L. When the bottom face <NUM> and the first side faces <NUM> are coated with the release agent, after the lithium ribbon L enters the recess <NUM>, the release agent on the bottom face <NUM> and the release agent on the first side faces <NUM> can be simultaneously transferred to the second surface L2 and the first surfaces L1 of the lithium ribbon L, thus completing the simultaneous coating of the second surface L2 and the first surfaces L1 with the release agent. The second surface L2 and the two first surfaces L1 of the lithium ribbon L are simultaneously coated with the release agent by means of the bottom face <NUM> and the two first side faces <NUM>, which can ensure the coating effect and achieve high coating efficiency.

In addition, the position of the lithium ribbon L is easily offset during running of the lithium ribbon L. When the lithium ribbon L cooperates with the recess <NUM>, since the two first side faces <NUM> correspond to the two first surfaces L1, the two first side faces <NUM> can also achieve a limiting effect, thus ensuring that the first surfaces L1 and the second surface L2 of the lithium ribbon L can be coated with the release agent.

As shown in <FIG> and <FIG>, an included angle α is formed between each of the first side faces <NUM> and the bottom face <NUM>.

For example, in some embodiments of the present application, the included angle α may be a right angle.

For another example, in some embodiments of the present application, as shown in <FIG>, the included angle α may also be an obtuse angle. That is, the first side faces <NUM> and the bottom face <NUM> are disposed in an inclined manner. In this case, the first side faces <NUM> have a large area, and thus the first surfaces L1 can be coated with more release agent, so as to ensure that sufficient release agent is provided on the extended portions of the lithium ribbon L after the lithium ribbon L is rolled.

Optionally, the included angle α is <NUM>° to facilitate machining.

According to some embodiments of the present application, as shown in <FIG>, the coating mechanism <NUM> further comprises a fixed roller <NUM>, at least a part of the fixed roller <NUM> being inserted in the recess <NUM> and forming a gap with the recess <NUM>, and the fixed roller <NUM> being used to control the thickness of the release agent adhering to the coating roller <NUM>. The gap between the part of the fixed roller <NUM> inserted in the recess <NUM> and the recess <NUM> means that the contour of structure of the part of the fixed roller <NUM> matches the contour of the recess <NUM>, and the part of the fixed roller <NUM> is inserted in the recess <NUM> and forms a gap with the recess face of the recess <NUM>, the gap allowing the release agent to pass through. The thickness of the release agent adhering to the coating roller <NUM> can be controlled by means of controlling the width of the gap between the fixed roller <NUM> and the recess <NUM>. That is, the fixed roller <NUM> is fixedly disposed, the coating roller <NUM> is rotatably disposed, and the coating roller <NUM> can rotate relative to the fixed roller <NUM>. The cooperation of the fixed roller <NUM> and the recess <NUM> can control the thickness of the release agent on the coating roller <NUM> to ensure that the thickness of the release agent adhering to the surface of the lithium ribbon L is consistent.

Specifically, after the lithium ribbon L enters the recess <NUM>, since the gap between the fixed roller <NUM> and the coating roller <NUM> is fixed, the fixed roller <NUM> scrapes off the extra-thick part of the release agent on the coating roller <NUM> through rotation of the coating roller <NUM>, so that the thickness of the release agent on the coating roller <NUM> is approximately equal to the width of the gap, and thus the thickness of the release agent on the coating roller <NUM> is consistent. When the coating roller <NUM> cooperates with the lithium ribbon L, the release agent on the coating roller <NUM> is transferred to the first surface L1 of the lithium ribbon L, thereby completing the coating of the first surface L1 with the release agent. The uniform thickness of the release agent on the coating roller <NUM> can alleviate the problem of uneven coating due to the uneven supply of the release agent by the coating roller <NUM>, so that the thickness of the release agent on the first surface L1 is consistent.

According to some embodiments of the present application, as shown in <FIG>, a roller face of the fixed roller <NUM> is provided with a boss <NUM>, the boss <NUM> being inserted in the recess <NUM> and forms a gap with the recess <NUM>. That is, the contour of the boss <NUM> matches the contour of the recess <NUM>, and the value of depth of the boss <NUM> inserted into the recess <NUM> determines the size of the gap between the boss <NUM> and the recess <NUM>, so that the adjustment of the depth of the boss <NUM> inserted into the recess <NUM> can change the gap between the boss <NUM> and the recess <NUM> and then control the thickness of the release agent on the coating roller <NUM>. The thickness of the release agent adhering to the coating roller <NUM> is controlled by means of the gap between the boss <NUM> and the recess <NUM>, achieving a simple structure and convenient operation.

According to some embodiments of the present application, the boss <NUM> is an annular boss disposed around the axis of the fixed roller <NUM> to facilitate machining.

<FIG> shows a schematic diagram of the operating state of a coating mechanism <NUM> according to an embodiment of the present application. According to some other embodiments of the present application, as shown in <FIG>, the boss <NUM> is disposed around the axis of the fixed roller <NUM>, and the boss <NUM> has a notch <NUM> in a circumferential direction of the fixed roller <NUM>. In other words, on the basis of the boss <NUM> of an annular structure, the notch <NUM> is formed in the boss <NUM> to control the thickness of the release agent on the coating roller <NUM>. Specifically, in the circumferential direction of the fixed roller <NUM>, the notch <NUM> cuts off the annular boss <NUM>. In addition, the notch <NUM> penetrates the boss <NUM> in the axial direction of the fixed roller <NUM>, so that a fixed roller scraper <NUM> is formed at an edge of the notch <NUM> of the boss <NUM> close to the recess <NUM>. The fixed roller scraper <NUM> matches the contour of the recess <NUM>, and the thickness of the release agent adhering to the recess face of the recess <NUM> is determined by means of a gap between the fixed roller scraper <NUM> and the recess <NUM>, thereby controlling the thickness of the release agent on the coating roller <NUM>.

During the operation of the coating roller <NUM>, in the direction of rotation around the coating roller <NUM>, the coating roller <NUM> first passes across the fixed roller <NUM> and cooperates with the fixed roller <NUM> to control the thickness of the release agent on the coating roller <NUM>, and then the coating roller <NUM> coats the second surface L2 and the first surface L1 of the lithium ribbon L with the release agent.

According to some embodiments of the present application, the fixed roller <NUM> is located on the side of the coating roller <NUM> that is away from the lithium ribbon L. That is, the fixed roller <NUM> and the lithium ribbon L are disposed at <NUM>° in the direction of rotation of the coating roller <NUM>. This arrangement achieves rational utilization of the installation space to avoid affecting the running of the lithium ribbon L.

It should be noted that the position of the fixed roller <NUM> may be determined according to the actual prelithiation condition. When it is ensured that the running of the lithium ribbon L is not affected and no interference with another component occurs, the fixed roller <NUM> may be disposed at any position in the direction of rotation of the coating roller <NUM>, provided that it can be ensured that the thickness of the release agent on the coating roller <NUM> is consistent.

According to some embodiments of the present application, the coating mechanism <NUM> may further comprise a release agent squeezing mechanism (not shown) that is used to squeeze the release agent between the coating roller <NUM> and the fixed roller <NUM>. For example, a storage apparatus is connected by means of a conduit, and the release agent is squeezed between the coating roller <NUM> and the fixed roller <NUM> through the conduit by means of a pumping mechanism.

According to some embodiments of the present application, as shown in <FIG> and <FIG>, the coating mechanism <NUM> further comprises a support roller <NUM>, and the lithium ribbon L passes between the support roller <NUM> and the coating roller <NUM>. That is, the support roller <NUM> comes into contact with a third surface L3 of the lithium ribbon L on the side away from the second roller <NUM> (see <FIG>), and supports the third surface L3 (see <FIG>). The lithium ribbon L will shake during running of the lithium ribbon L. The lithium ribbon L is limited between the support roller <NUM> and the coating roller <NUM> by means of the cooperation of the support roller <NUM> and the coating roller <NUM>, so as to ensure that the first surface L1 and the second surface L2 of the lithium ribbon L can be simultaneously coated with the release agent and ensure that the release agent adhering to the surface of the lithium ribbon L is uniform. For example, as shown in <FIG>, the support roller <NUM> is disposed in parallel with the coating roller <NUM>, the size of the recess <NUM> of the coating roller <NUM> is slightly greater than that of the lithium ribbon L, the roller face of the support roller <NUM> adheres to the roller face of the coating roller <NUM>, the support roller <NUM> presses the lithium ribbon L into the recess <NUM> of the coating roller <NUM>, and the contact stress between the support roller <NUM> and the lithium ribbon L is stable, which ensures that the gap between the lithium ribbon L and the recess <NUM> is fixed and then ensures that the release agent coating on the surface of the lithium ribbon L is uniform.

It should be noted that the axial dimension of the support roller <NUM> is greater than the dimension of the recess <NUM> of the coating roller <NUM> in the axial direction of the coating roller <NUM>. In addition, when the support roller <NUM> cooperates with the coating roller <NUM>, the projection of the recess <NUM> is located in the projection of the support roller <NUM> in a thickness direction of the lithium ribbon L.

In addition, since the support roller <NUM> presses the lithium ribbon L into the recess <NUM>, the two first side faces <NUM> of the recess <NUM> can limit the movement of the lithium ribbon L in the width direction, thereby achieving a limiting effect.

When the support roller <NUM> cooperates with the coating roller <NUM>, the support roller <NUM> presses the lithium ribbon L into the recess <NUM>, and as the coating roller <NUM> rotates, the second surface L2 and the two first surfaces L1 of the lithium ribbon L can be simultaneously coated with the release agent by means of the recess <NUM>, thereby ensuring the uniformity of the release agent adhering to the surface of the lithium ribbon L to ensure the coating effect.

<FIG> shows a schematic structural diagram of a coating mechanism <NUM> according to another embodiment of the present application; and <FIG> shows a schematic structural diagram of a coating mechanism <NUM> according to still another embodiment of the present application. With regard to the coating mechanism <NUM>, in addition to the above method of transferring and coating the release agent by means of the coating roller <NUM>, according to some other embodiments of the present application, the coating mechanism <NUM> may also be a spray-coating mechanism. That is, as shown in <FIG> and <FIG>, the coating mechanism <NUM> comprises a nozzle <NUM>, and the nozzle <NUM> is configured to simultaneously coat the second surface L2 and the first surface L1 of the lithium ribbon L with the release agent. The coating mechanism <NUM> is provided with an accommodating recess <NUM> for accommodating the lithium ribbon L. The accommodating recess <NUM> can accommodate at least the second surface L2 and the two first surfaces L1 of the lithium ribbon L. For example, as shown in <FIG>, the accommodating recess <NUM> can accommodate the second surface L2 and the two first surfaces L1 of the lithium ribbon L. For another example, as shown in <FIG>, the accommodating recess <NUM> can accommodate all surfaces of the lithium ribbon L including the second surface L2 and the two first surfaces L1, that is, the accommodating recess <NUM> is an annular recess, and the lithium ribbon L passes through the accommodating recess <NUM>. It should be noted that <FIG> and <FIG> are only schematic diagrams of the arrangement of the nozzle <NUM> of the coating mechanism <NUM>, and other components are not disclosed.

<FIG> shows a schematic diagram of a prelithiation device during prelithiation according to an embodiment of the present application.

Generally, as shown in <FIG>, the prelithiation device further comprises a lithium ribbon conveying mechanism <NUM> and a substrate conveying mechanism <NUM>, the lithium ribbon conveying mechanism <NUM> being used to feed the lithium ribbon L between the first roller <NUM> and the second roller <NUM>, and the substrate conveying mechanism <NUM> being used to feed the substrate P between the second roller <NUM> and the third roller <NUM>.

The lithium ribbon conveying mechanism <NUM> comprises a lithium ribbon unwinding roller <NUM>. The lithium ribbon unwinding roller <NUM> is configured to arrange the lithium ribbon L. For example, the lithium ribbon L may be disposed on the lithium ribbon unwinding roller <NUM> in a winding manner, and the lithium ribbon L is fed between the first roller <NUM> and the second roller <NUM> through rotation of the lithium ribbon unwinding roller <NUM>. The substrate conveying mechanism <NUM> comprises a substrate unwinding roller <NUM> and a substrate winding roller <NUM>. The substrate unwinding roller <NUM> and the substrate winding roller <NUM> are used to arrange the substrate P. For example, the substrate P may be disposed on the substrate unwinding roller <NUM> and the substrate winding roller <NUM> in a winding manner.

While the lithium ribbon L is fed between the second roller <NUM> and the third roller <NUM>, since the substrate conveying mechanism <NUM> feeds the substrate P between the second roller <NUM> and the third roller <NUM>, the lithium ribbon L and the substrate P are simultaneously located in a roller gap between the second roller <NUM> and the third roller <NUM>. Compared with the roller face of the second roller <NUM>, the substrate P has a larger surface roughness, and the adhesive force between the lithium ribbon L and the substrate P is greater than that between the lithium ribbon L and the second roller <NUM>. When the lithium ribbon L comes into contact with the substrate P and is rolled, the lithium ribbon L adheres to the substrate P, and as the substrate P is conveyed, the substrate P pulls the lithium ribbon L, so that the lithium ribbon L is peeled off from the roller face of the second roller <NUM>, thereby coating the substrate P with lithium, that is, completing a prelithiation process for the substrate P.

To improve applicability of the bonding mechanism <NUM>, the prelithiation device further comprises a roller gap adjustment mechanism (not shown) for adjusting the roller gap between the first roller <NUM> and the second roller <NUM> and adjusting the roller gap between the second roller <NUM> and the third roller <NUM>, so as to regulate the rolling effect and the bonding effect of the bonding mechanism <NUM> and then adapt to different prelithiation requirements.

According to some embodiments of the present application, as shown in <FIG>, the prelithiation device further comprises a prepressing mechanism <NUM>. The prepressing mechanism <NUM> is disposed upstream of the coating mechanism <NUM> in the running direction of the lithium ribbon L, and the prepressing mechanism <NUM> is used to prepress the lithium ribbon L to improve the thickness consistency of the lithium ribbon L, so as to significantly improve the effect of coating the surface of the lithium ribbon L with the release agent. The thickness consistency of the lithium ribbon L is associated with manufacturing costs, and reducing the requirement for the thickness consistency of the lithium ribbon L can reduce the cost of incoming material of the lithium ribbon L. As shown in <FIG>, the prepressing mechanism <NUM> comprises two prepressing rollers <NUM>, and the lithium ribbon L first passes between the two prepressing rollers <NUM> and then passes across the coating mechanism <NUM>.

Under the rolling action of the prepressing mechanism <NUM>, the amount of compression of the lithium ribbon L is <NUM>% to <NUM>%. Since the lithium ribbon L has a small amount of compression and does not easily adhere to the prepressing rollers <NUM>, the two prepressing rollers <NUM> may be disposed upstream of the coating mechanism <NUM>.

According to some embodiments of the present application, the roller diameter of the first roller <NUM> is less than that of the second roller <NUM>. Different-diameter rolling can be implemented by configuration of large and small roller diameters. Compared with same-diameter rolling, the different-diameter rolling increases the contact area between the second roller <NUM> and the lithium ribbon L, and improves the engagement between the lithium ribbon L and the first roller <NUM> and the engagement between the lithium ribbon L and the second roller <NUM>, so that the lithium ribbon L more easily adheres to the roller face of the second roller <NUM>.

Since the first roller <NUM> has a small roller diameter, the first roller <NUM> is easily deformed during rolling, which reduces the thickness consistency of rolling. According to some embodiments of the present application, the bonding mechanism <NUM> further comprises a fourth roller <NUM>. The fourth roller <NUM> is disposed opposite the first roller <NUM> and is located on the side of the first roller <NUM> that is away from the second roller <NUM>. The fourth roller <NUM> has a roller diameter greater than that of the first roller <NUM>. The fourth roller <NUM> and the first roller <NUM> come into contact with each other and rotate relative to each other, which can reduce the deformation of the first roller <NUM> during long-term use, improve the thickness consistency of the lithium ribbon L during rolling, and prolong the service life of the device.

According to some embodiments of the present application, as shown in <FIG>, the prelithiation device further comprises a traction roller <NUM> and a traction belt <NUM>, the traction belt <NUM> being connected to the traction roller <NUM>, and the traction roller <NUM> being disposed downstream of the first roller <NUM> in the running direction of the lithium ribbon L. The traction roller <NUM> is a driving roller. When the lithium ribbon L needs to be pulled to run, the traction belt <NUM> may be connected to the lithium ribbon L, and then the lithium ribbon L is driven through rotation of the traction roller <NUM> to run. When the lithium ribbon L follows the traction belt <NUM> to enter between the first roller <NUM> and the second roller <NUM>, since the roller gap between the first roller <NUM> and the second roller <NUM> is smaller than the thickness of the lithium ribbon L, the thinned lithium ribbon L is separated from the traction belt <NUM> under the action of rolling pressure, and the lithium ribbon L adheres to the roller face of the second roller <NUM>.

If the traction roller <NUM> and the traction belt <NUM> are not provided, the lithium ribbon L needs to be manually pulled between the first roller <NUM> and the second roller <NUM>, and the lithium ribbon L is pulled by the first roller <NUM> and the second roller <NUM> to run. In this way, the coating mechanism <NUM> cannot coat an initial section of the lithium ribbon L with the release agent, so that the initial section of the lithium ribbon L will adhere to the surface of the first roller <NUM> or the second roller <NUM>. In this case, the initial section of the lithium ribbon L cannot be transferred to the surface of the substrate P, resulting in a waste of the lithium ribbon L and also reducing the flatness of the roller faces of the first roller <NUM> and the second roller <NUM> to affect the subsequent rolling of the lithium ribbon L.

After the lithium ribbon L is bonded to the substrate P, lithium filings and the release agent will remain on the roller face of the second roller <NUM>. In order to avoid affecting the rolling and bonding of the lithium ribbon L, it is necessary to remove the residue on the second roller <NUM> in a timely manner.

As shown in <FIG>, the prelithiation device further comprises a cleaning mechanism <NUM>. The cleaning mechanism <NUM> is used to clean the roller face of the second roller <NUM>. <FIG> shows a schematic diagram of the cleaning mechanism <NUM> according to an embodiment of the present application; and <FIG> shows another schematic diagram of the cleaning mechanism <NUM> according to an embodiment of the present application. As shown in <FIG>, the cleaning mechanism <NUM> comprises a cleaning scraper <NUM>, a cleaning brush <NUM>, and a dust collection assembly <NUM>, the cleaning scraper <NUM> abutting against the roller face of the second roller <NUM>, the cleaning brush <NUM> being in contact with the roller face of the second roller <NUM>, and the dust collection assembly <NUM> being used to remove the lithium filings and release agent scraped off by the cleaning scraper <NUM>. As the second roller <NUM> rotates, the cleaning scraper <NUM> scrapes off the residual lithium filings and release agent on the roller face of the second roller <NUM>. The cleaning brush <NUM> is located downstream of the cleaning scraper <NUM>, and is used to further clean the roller face of the second roller <NUM>. The dust collection assembly <NUM> may be disposed on a side of the cleaning scraper <NUM>, so as to remove the scraped lithium filings and release agent under the action of negative pressure.

A prelithiation method provided according to an embodiment of the present application will be described below, and the prelithiation method is implemented using the prelithiation device mentioned above. <FIG> shows a schematic flowchart of a prelithiation method according to an embodiment of the present application. As shown in <FIG>, the prelithiation method comprises:.

In the prelithiation method according to the embodiment of the present application, before the lithium ribbon L is rolled, the first surface L1 of the lithium ribbon L in the width direction is coated with the release agent, so that sufficient release agent is provided on an extended portion of the rolled lithium ribbon L so as to prevent the lithium ribbon L from sticking to the roller, thereby improving the production safety.

Claim 1:
A prelithiation device for bonding a lithium ribbon (L) to a substrate (P), the prelithiation device comprising:
a bonding mechanism (<NUM>) comprising a first roller (<NUM>), a second roller (<NUM>) and a third roller (<NUM>), which are sequentially disposed adjacent to each other, the first roller (<NUM>) and the second roller (<NUM>) being used to roll the lithium ribbon (L), with the rolled lithium ribbon (L) adhering to the second roller (<NUM>), and the second roller (<NUM>) and the third roller (<NUM>) being used to bond the lithium ribbon (L) adhering to the second roller (<NUM>) to the substrate (P),
the lithium ribbon (L) comprising two first surfaces (L1) opposite each other in a width direction of the lithium ribbon (L) and a second surface (L2) facing the second roller (<NUM>);
characterised in that the prelithiation device further comprises:
a coating mechanism (<NUM>) disposed upstream of the bonding mechanism (<NUM>) in a running direction of the lithium ribbon (L) and configured to simultaneously coat the second surface (L2) and at least one of the first surfaces (L1) with a release agent.