WO2023035780A1

WO2023035780A1 - Lithium supplementing device

Info

Publication number: WO2023035780A1
Application number: PCT/CN2022/106662
Authority: WO
Inventors: 李云明; 王学飞
Original assignee: 蜂巢能源科技股份有限公司
Priority date: 2021-09-07
Filing date: 2022-07-20
Publication date: 2023-03-16
Also published as: CN216161767U

Abstract

Disclosed is a lithium supplementing device. The lithium supplementing device comprises: a pole piece conveying mechanism configured to convey a pole piece; a lithium band conveying mechanism configured to convey a lithium band; a calendering mechanism, comprising a first calendering roller and a second calendering roller, with a gap capable of accommodating a lithium band being provided between the first calendering roller and the second calendering roller; a transfer roller is located between the second calendering roller and the pole piece and abuts the pole piece, and an auxiliary film is sleeved between the second calendering roller and the transfer roller; when a lithium band is located in the gap, two sides of the lithium band respectively abut the first calendering roller and the auxiliary film; the calendering mechanism is configured for calendering a lithium band through the gap to form a lithium foil, and for adhering same to an auxiliary film, and the transfer roller is configured for attaching to a pole piece the lithium foil adhered to the auxiliary film.

Description

Lithium supplementation device

This application claims the priority of the Chinese patent application with application number 202122147500.6 submitted to the China Patent Office on September 07, 2021, the entire content of which is incorporated herein by reference.

technical field

The present application relates to the technical field of production and manufacture of lithium batteries, for example, to a lithium replenishment device.

Background technique

Due to the advantages of high energy density, long cycle life and no memory effect, lithium-ion batteries are widely used in consumer electronics and new energy vehicles. However, during the first charging and discharging process of the electrode material of the lithium-ion battery, the loss of lithium caused by the formation of the solid electrolyte film will limit the energy density of the lithium-ion battery, especially in the silicon-based negative electrode material system, and in the cycle The loss of active lithium caused by side reactions in the process will shorten the cycle life.

In order to solve this problem, the related technology uses a lithium replenishment device to supplement lithium to the pole piece, so as to achieve the purpose of improving the energy density and cycle life of the lithium ion battery. Lithium supplementation device has the following two forms:

The first type is that the lithium replenishing device adopts the form of split calendering one-time coating. The lithium replenishing device includes a pole piece conveying mechanism, a lithium belt conveying mechanism, an auxiliary film conveying mechanism and a transfer mechanism. The pole piece conveying mechanism is set to transport the pole piece , the lithium belt conveying mechanism is set to convey the lithium belt, the auxiliary film conveying mechanism is set to convey the auxiliary film, the two sides of the lithium belt can be respectively abutted against the auxiliary film and the transfer mechanism, so as to bond the rolled lithium belt to the transfer mechanism On the surface, the transfer mechanism transports the lithium belt to the pole piece, thereby realizing the process of lithium supplementation for the pole piece. Since the two sides of the lithium ribbon can contact the auxiliary film and the transfer mechanism respectively, the auxiliary film provides support for the lithium ribbon, and the auxiliary film only covers the surface of the lithium ribbon once during the lithium replenishment process. As far as the electrode is concerned, the auxiliary film with double the area of the pole piece needs to be consumed, and the auxiliary film cannot be reused, resulting in high cost of lithium supplementation.

The second type is that the lithium supplementary device adopts the form of integral calendering without an auxiliary film. The transfer mechanism of the lithium supplementary device not only plays the role of transfer, but also plays the role of calendering. For the calendering process, the transfer mechanism needs to have a relatively Small size to roll thicker lithium ribbon to thinner lithium foil; for the transfer process, the transfer mechanism needs to have a larger size to reduce the extension effect of the pole piece, and the transfer mechanism is difficult to be compatible with the calendering process and Problems with the transfer process.

Contents of the invention

The application provides a lithium supplementation device, which can meet the functional requirements of calendering and transfer at the same time, realize the circulation of the auxiliary membrane, and save production costs.

A lithium supplement device, comprising:

The pole piece conveying mechanism is configured to convey the pole piece;

The lithium belt conveying mechanism is set to convey the lithium belt;

A calendering mechanism, including a first calendering roll and a second calendering roll, a gap capable of accommodating the lithium belt is provided between the first calendering roll and the second calendering roll;

a transfer roll, located between the second calender roll and the pole piece and abutting against the pole piece, an auxiliary film is sleeved between the second calender roll and the transfer roll;

When the lithium ribbon is located in the gap, both sides of the lithium ribbon abut against the first calendering roll and the auxiliary film respectively, and the calendering mechanism is configured to pass through the gap The lithium ribbon is rolled into a lithium foil and adhered to the auxiliary film, and the transfer roller is configured to attach the lithium foil adhered to the auxiliary film to the pole piece.

Description of drawings

Fig. 1 is a schematic structural diagram of a lithium supplementation device provided in an embodiment of the present application;

2 is a schematic structural view of the surface of a transfer roller in a lithium supplementation device provided in an embodiment of the present application;

FIG. 3 is a schematic structural view of the surface of a transfer roller in another lithium supplementation device provided in an embodiment of the present application.

In the picture:

100. Auxiliary film;

1. Electrode conveying mechanism; 2. Lithium belt conveying mechanism; 3. Support roller; 4. Calendering mechanism; 5. Release agent coating mechanism; 6. Cleaning mechanism; 7. Transfer roller;

11. Pole piece discharging roller; 12. Pole piece receiving roller;

41. The first calender roll; 42. The second calender roll;

71. Raised.

Detailed ways

The technical solutions of the embodiments of the present application will be described below in conjunction with the accompanying drawings, and the described embodiments are only part of the embodiments of the present application.

In the description of this application, unless otherwise stipulated and limited, the terms "connected", "connected" and "fixed" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral body; It can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediary, it can be the internal communication of two components or the interaction relationship between two components. Those of ordinary skill in the art can understand the meanings of the above terms in this application according to the situation.

In this application, unless otherwise specified and limited, a first feature being "on" or "under" a second feature may include that the first and second features are in direct contact, and may also include that the first and second features are not in direct contact. contact but through additional feature contact between them. Moreover, "above", "above" and "above" the first feature on the second feature include that the first feature is directly above and obliquely above the second feature, or simply means that the first feature is horizontally higher than the second feature. "Below", "beneath" and "under" the first feature to the second feature include that the first feature is directly below and obliquely below the second feature, or simply means that the first feature has a lower level than the second feature.

The technical solution of the present application will be described below in conjunction with the accompanying drawings and through specific implementation methods.

This embodiment provides a lithium replenishing device, which is configured to replenish lithium to a pole piece. As shown in Figure 1, the lithium replenishing device includes a pole piece conveying mechanism 1, a lithium belt conveying mechanism 2, a calendering mechanism 4, and a transfer roller 7, the pole piece conveying mechanism 1 is set to convey pole pieces, and the lithium belt conveying mechanism 2 is set to convey Lithium strip, calendering mechanism 4 is set to calendering lithium strip, is wound with auxiliary film 100 between calendering mechanism 4 and transfer roller 7, and lithium strip can be calendered into lithium foil and adheres to the surface of auxiliary film 100, and auxiliary film 100 is Lithium straps provide support and transfer. The transfer roller 7 is located between the calendering mechanism 4 and the pole piece and abuts against the pole piece. The transfer roller 7 plays the role of intermediate transfer, and the lithium foil is attached to the pole piece through the transfer roller 7 .

The pole piece conveying mechanism 1 includes a pole piece discharge roller 11 and a pole piece take-up roller 12, the pole piece is respectively wound around the pole piece discharge roller 11 and the pole piece take-up roller 12, and the pole piece discharge roller 11 is set as a pole piece The feeding of the pole piece, the pole piece receiving roller 12 is set to complete the collection of the lithium supplemented pole piece. At least one of the pole piece discharging roller 11 and the pole piece receiving roller 12 can rotate to drive the movement of the pole piece, thereby realizing the conveying process of the pole piece. The lithium belt conveying mechanism 2 includes a lithium belt discharge roller, the lithium belt is wound on the outside of the lithium belt discharge roller, the lithium belt discharge roller is set as the discharge of the lithium belt, and the lithium belt discharge roller can rotate to drive the movement of the lithium belt , so as to realize the conveying process of the lithium belt.

If the auxiliary film 100 only covers the surface of the lithium strip at one time during the lithium supplementation process, for a pole piece that needs lithium supplementation on both sides, the auxiliary film 100 with double the area of the pole piece needs to be consumed, and the auxiliary film 100 cannot Repeated use causes the cost of lithium supplementation to be too high. At the same time, if the calendering mechanism 4 and the transfer roller 7 are used for calendering, the transfer roller 7 has the problem that the two processes of the calendering process and the transfer process cannot be compatible.

In order to solve this problem, the calendering mechanism 4 includes a first calendering roll 41 and a second calendering roll 42, a gap that can accommodate and calender the lithium band is provided between the first calendering roll 41 and the second calendering roll 42, and the lithium band conveying mechanism 2. The lithium ribbon can be released to the gap between the first calender roll 41 and the second calender roll 42. If the thickness of the lithium ribbon is greater than 1 mm, the lithium ribbon is a thick lithium ribbon. The gap between the first calender roll 41 and the second calender roll 42 is The gap between them is small, and under the joint action of the first calender roll 41 and the second calender roll 42, the lithium strip can be rolled to the lithium foil, and the thickness of the lithium foil is between 2 μm-10 μm, so as to complete the rolling of the thick lithium strip to ultrathin lithium foil.

During this process, the auxiliary film 100 is sleeved between the second calender roll 42 and the transfer roll 7, and the second calender roll 42 also realizes the supply of the auxiliary film 100 while realizing the calendering function. Both sides of the lithium ribbon can contact the first calender roll 41 and the auxiliary film 100 respectively, and the auxiliary film 100 provides support and transfer for the lithium ribbon. The lithium ribbon can be rolled into a lithium foil and adhered to the auxiliary film 100, and the lithium foil is attached to the pole piece by the transfer roller 7, and the transfer roller 7 plays the role of transferring the lithium foil. At the same time, the pole piece conveying mechanism 1 is set to transport the pole piece. By setting the transfer roller 7 between the second calender roll 42 and the pole piece and abutting against the pole piece, it adheres to the auxiliary film 100 under the action of pressure. The lithium foil on the surface of the electrode is attached to the pole piece, thereby completing the lithium replenishment process for the pole piece.

The lithium replenishing device provided in this embodiment, under the joint action of the transfer roller 7 and the second calender roller 42, enables the auxiliary film 100 to form a closed ring structure to realize the recycling of the auxiliary film 100, which is different from the auxiliary film 100 in the related art. Compared with disposable use, by introducing the auxiliary membrane 100 that can be recycled in a closed loop, the auxiliary membrane 100 has a high reusability rate and saves production costs. A gap that can accommodate and calender the lithium strip is provided between the first calender roller 41 and the second calender roller 42 to complete the calendering process, and the auxiliary film 100 attaches the lithium foil to the pole piece through the transfer roller 7 to complete the lithium foil In the transfer lamination process, the calendering process and the transfer process are separated by adding the auxiliary film 100, which can meet the functional requirements of calendering and transfer at the same time, and has good compatibility.

Both the diameters of the first calendering roll 41 and the second calendering roll 42 are d, and the diameter of the transfer roll 7 is D, where d<D. In this embodiment, 100mm≤d≤200mm, 200mm≤D≤500mm. By setting the diameters of the two calendering rolls to be small, and using two calendering rolls with small roll diameters in the calendering process, a thicker lithium ribbon can be rolled to a thinner lithium foil, thereby realizing the preparation of an ultra-thin metal lithium foil. By setting the diameter of the transfer roller 7 to be relatively large, the transfer roller 7 with a large diameter is used in the transfer process to avoid the extension of the pole piece caused by the lithium foil during the transfer process, so as to achieve the purpose of reducing the extension effect of the pole piece.

The linear velocity v1 of the first calendering roll 41 is less than or equal to the linear velocity v2 of the second calendering roll 42 , and in this embodiment, 0.4≦v1/v2≦1. By setting the linear velocity v1 of the first calendering roll 41 to be less than or equal to the linear velocity v2 of the second calendering roll 42, there is a linear velocity difference between the two calendering rolls to ensure the calendering effect of the lithium foil.

Since the auxiliary film 100 supports the thinned and elongated lithium foil during the rolling process of the lithium ribbon, when the lithium foil needs to be adhered to the pole piece, it is required that the lithium foil can be separated from the auxiliary film 100. If the lithium foil It cannot be separated from the auxiliary film 100, and the auxiliary film 100 is easy to deviate along with the movement of the lithium strip, which affects the transfer of the lithium foil by the transfer roller 7.

In order to solve this problem, the total friction force between the auxiliary film 100 and the second calender roll 42 and the transfer roll 7 is greater than the friction force between the auxiliary film 100 and the lithium belt, that is, the auxiliary film 100 and the second calender roll 42 The sum of the friction force between them and the friction force between the auxiliary film 100 and the transfer roller 7 is greater than the friction force between the auxiliary film 100 and the lithium ribbon. The auxiliary film 100 is made of polyester fiber (Polyester, PET) film, polypropylene (Polypropylene, PP) film, polyethylene (Polyethylene, PE) film or stainless steel foil, the outer surface of the auxiliary film 100 is smoothed, and the auxiliary film The inner surface of the film 100 is roughened, so that the total friction between the inner surface of the auxiliary film 100 and the second calender roll 42 and the transfer roll 7 is greater than the resistance of the calender mechanism 4 and the transfer roll 7 when rolling the lithium strip, so as to realize the auxiliary The film 100 operates synchronously with the second calender roll 42 and the transfer roll 7 to avoid deviation of the auxiliary film 100 and ensure the lithium replenishment effect of the transfer roll 7 on the pole piece.

In order to realize the extension and calendering of the lithium ribbon, and attach the extended lithium foil to the auxiliary film 100, before calendering the lithium ribbon, the surfaces of both sides of the lithium ribbon are coated with a release agent, such as polymethyl Silicones and polyethers. By adjusting the type and coating amount of the release agent, the release force on the side of the auxiliary film is greater than the release force of the first calender roll 41, so that the lithium foil can be completely pasted on the outer surface of the auxiliary film 100, while ensuring the rolling effect of the lithium strip. At the same time, the separation of the lithium foil and the first calender roll 41 is ensured.

A conductive agent or a lithium salt or a mixture of a conductive agent and a lithium salt is added to the release agent, so that the release agent has ionic, electronic or mixed conductivity, thereby reducing the effect of the release agent on the diffusion of lithium ions.

In order to improve the calendering effect of the metal lithium foil, the lithium replenishing device also includes a release agent coating mechanism 5, which is located between the lithium belt conveying mechanism 2 and the first calendering roller 41, and is set to the lithium belt Coating the release agent plays the role of recoating the release agent to the lithium tape. The coating method can be one of spray coating, extrusion coating and transfer coating.

The lithium replenishing device also includes a support roll 3, and the auxiliary film 100 is sleeved on the outside of the support roll 3, the second calender roll 42 and the transfer roll 7, under the joint action of the support roll 3, the second calender roll 42 and the transfer roll 7 , so that the auxiliary film 100 can form a closed-loop structure to realize the recycling of the auxiliary film 100. Compared with the one-time use of the auxiliary film 100 in the related art, by introducing the auxiliary film 100 that can be recycled in a closed loop, the reusability of the auxiliary film 100 is improved. High, saving production costs.

The position of the support roller 3 is adjustable, and the tension of the auxiliary film 100 can be controlled by controlling the position of the support roller 3 .

The auxiliary film 100 is detachably connected to the support roll 3 and the second calender roll 42 . By setting the auxiliary film 100 as a detachable structure, the auxiliary film 100 can be replaced regularly according to the release force and damage degree of the outer surface during use, so as to ensure that the auxiliary film 100 always has a good auxiliary supporting effect on the lithium ribbon.

In order to improve the electrolyte infiltration effect of the pole piece, the lithium replenishment method can also be stripe lithium replenishment. In order to realize stripe lithium replenishment, as shown in FIGS. 1-3 , the outer wall of the transfer roller 7 is provided with protrusions 71 . By providing the protrusion 71, the protrusion 71 can reduce the contact area and increase the pressure. Under the action of the pressure, the lithium foil corresponding to the position of the protrusion 71 can be better transferred to the pole piece.

Protrusion 71 can be arranged along the circumference of transfer roller 7 (as shown in Figure 2), and the quantity of protrusion 71 can be a plurality of, and the extension direction of a plurality of protrusions 71 is arranged in parallel with the axial direction of transfer roller 7 and along the transfer roller 7. The circumferential direction of the rollers 7 is distributed in parallel and at intervals to form a transverse stripe structure.

Protrusion 71 can be arranged along the axial direction of transfer roller 7 (as shown in Figure 3), the quantity of protrusion 71 can be a plurality of, the extension direction of a plurality of protrusions 71 and the axial direction of described transfer roller 7 are perpendicular to each other and They are distributed in parallel and at intervals along the axial direction of the transfer roller 7 to form a vertical stripe structure. The striped structure is used to improve the uniformity of lithium foil transfer.

Since residues inevitably remain between two adjacent protrusions 71 during the transfer process, for this reason, as shown in FIG. To prevent the remaining metal lithium residue from adhering to the pole piece, thereby affecting the flatness of the pole piece surface. The cleaning mechanism 6 includes a scraper and a suction nozzle, the scraper is set to separate the residue from the auxiliary film 100, and the suction nozzle is set to suck the residue.

The above-mentioned mechanism can be set as one-sided lithium replenishment of the pole piece. If the pole piece needs double-sided lithium supplementation, the lithium belt conveying mechanism 2, the support roller 3, the first calender roller 41, the second calender roller 42, the transfer roller 7, the There are two formulation coating mechanisms 5 and two cleaning mechanisms 6, which are symmetrically arranged on both sides of the pole piece, which is equivalent to two sets of systems simultaneously replenishing lithium on both sides of the pole piece, with good synchronization and high production efficiency.

In the description herein, the terms "upper", "lower", "right", and other orientations or positional relationships are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of description and simplification of operations, rather than indicating or implying References to devices or elements must have a particular orientation, be constructed, and operate in a particular orientation and therefore should not be construed as limiting the application. In addition, the terms "first" and "second" are only used for distinction in description and have no special meaning.

In the description of this specification, descriptions with reference to the terms "an embodiment", "example" and the like mean that the features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application . In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example.

Claims

A lithium supplement device, comprising:

The pole piece transport mechanism (1) is configured to transport the pole piece;

The lithium belt conveying mechanism (2) is set to convey the lithium belt;

The calendering mechanism (4) comprises a first calendering roller (41) and a second calendering roller (42), and a device capable of accommodating all The gap between the lithium strips;

A transfer roll (7), located between the second calender roll (42) and the pole piece and abutting on the pole piece, between the second calender roll (42) and the transfer roll (7) An auxiliary film (100) is set between them;

When the lithium ribbon is located in the gap, both sides of the lithium ribbon are in contact with the first calender roll (41) and the auxiliary film (100), respectively, and the calender mechanism (4) set to roll the lithium ribbon into a lithium foil through the gap and stick it on the auxiliary film (100), and the transfer roller (7) is set to roll the lithium foil stuck on the auxiliary film (100) The lithium foil is attached to the pole piece.
The lithium replenishing device according to claim 1, wherein the diameter of the first calender roll (41) and the diameter of the second calender roll (42) are both d, and the diameter of the transfer roll (7) is D, where d is less than D.
The lithium replenishing device according to claim 1, wherein the linear velocity of the first calendering roll (41) is less than or equal to the linear velocity of the second calendering roll (42).
The lithium replenishing device according to claim 1, further comprising a release agent coating mechanism (5), and the release agent coating mechanism (5) is located between the lithium belt conveying mechanism (2) and the first calender Between the rollers (41), it is arranged to apply a release agent to the lithium belt.
The lithium replenishing device according to claim 4, wherein a conductive agent or a lithium salt or a mixture of a conductive agent and a lithium salt is added in the release agent.
The lithium supplementing device according to claim 1, wherein the total friction force between the auxiliary film (100) and the second calender roll (42) and the transfer roll (7) is greater than the auxiliary film ( 100) and the friction between the lithium ribbon.
The lithium replenishing device according to claim 1, further comprising a support roll (3), the auxiliary film (100) is sheathed on the support roll (3), the second calender roll (42) and the transfer The outside of the roller (7).
The lithium replenishing device according to claim 1, wherein, the outer wall of the transfer roller (7) is provided with protrusions (71).
The lithium replenishing device according to claim 8, wherein the number of the protrusions (71) can be multiple, and the extension direction of the plurality of protrusions (71) is perpendicular to the axial direction of the transfer roller (7) And along the axial direction of the transfer roller (7), distributed in parallel and at intervals, or the extension direction of the plurality of protrusions (71) is arranged parallel to the axial direction of the transfer roller (7) and along the direction of the transfer roller (7) Circumferentially distributed in parallel intervals.
The lithium supplementing device according to claim 8, further comprising a cleaning mechanism (6), the cleaning mechanism (6) being configured to clean residues on the auxiliary membrane (100).