CN113725397A

CN113725397A - Fast response transfer multiplexing method

Info

Publication number: CN113725397A
Application number: CN202111285463.3A
Authority: CN
Inventors: 齐大志; 程滋平; 刘慧芳; 陈强; 牟瀚波; 吴春敢
Original assignee: China Energy Lithium Co ltd
Current assignee: China Energy Lithium Co ltd
Priority date: 2021-11-02
Filing date: 2021-11-02
Publication date: 2021-11-30
Anticipated expiration: 2041-11-02
Also published as: CN113725397B

Abstract

The invention discloses a quick response transfer combination method, which comprises the following steps: providing a lithium film, wherein the lithium film is composed of a support film and an ultrathin lithium layer, the ultrathin lithium layer side of the lithium film is called a lithium layer side, and the opposite support film side of the lithium film is called a thin film side; providing a pole piece; providing a pair roller device, wherein the pair roller device comprises a fixed roller and a floating roller which are oppositely arranged up and down, the fixed roller can only rotate around the axis of the fixed roller, and the floating roller can rotate around the axis of the floating roller and can also move up and down along the vertical direction; and arranging the lithium layer side of the lithium film opposite to the pole piece, and rolling by using a roller device, wherein the floating roller moves in the vertical direction and automatically adjusts in response to the thickness change of the lithium film and the pole piece. The floating roller keeps constant pressure, and the vertical movement of the floating roller is automatically adjusted according to the thicknesses of the lithium film and the pole piece, so that the pressure born by all the positions of the lithium film and the pole piece is constant, and the stability of the transfer lamination process and the better consistency of the final product are ensured.

Description

Fast response transfer multiplexing method

Technical Field

The invention relates to the technical field of battery manufacturing, in particular to a quick response transfer combination method for pre-lithiation of a lithium battery.

Background

Lithium ion batteries have become one of the most widely used secondary batteries due to their advantages of high specific energy, small size and long cycle life. However, with the continuous development of high-power and high-energy devices such as electronic devices and electric vehicles, the demand for energy density of lithium ion batteries is higher and higher.

It has been proven that the energy density of a lithium ion battery can be effectively improved by coating lithium on a pole piece. The thickness of the lithium-on-pole piece is usually in the micron order, the lithium layer is attached to a film, and the lithium layer needs to be transferred from the film to the pole piece during lithium coating. However, the existing method cannot completely transfer the ultrathin lithium layer on the lithium film to the pole piece, and the situations of transfer leakage, pole piece wrinkling and the like often exist.

Disclosure of Invention

The invention aims to overcome the defects in the prior art and provides a novel quick response transfer combination method for pre-lithiation of a lithium battery, which is simple and reliable in operation, so that the requirement of the lithium battery for pre-lithiation is met.

The method provided by the invention applies constant pressure through the quick-response floating roller, and the roll gap is dynamically adjusted along with the thicknesses of the lithium film and the pole piece, so that the same bearing pressure at any position of the pole piece and the lithium film is ensured, the stability of the transfer lamination process is realized, and the better consistency of the final product is ensured.

The purpose of the invention can be realized by the following technical scheme.

A fast response transfer compounding method, comprising: providing a lithium film, wherein the lithium film is composed of a support film and an ultrathin lithium layer with the thickness of 2-20 μm, the ultrathin lithium layer side of the lithium film is called a lithium layer side, and the opposite support film side of the lithium film is called a thin film side; providing a pole piece; providing a pair roller device, wherein the pair roller device comprises a fixed roller and a floating roller which are oppositely arranged up and down, the fixed roller can only rotate around the axis of the fixed roller, and the floating roller can rotate around the axis of the floating roller and can also move up and down along the vertical direction; and arranging the lithium layer side of the lithium film opposite to the pole piece, and rolling by using a roller device, wherein the floating roller moves in the vertical direction and automatically adjusts in response to the thickness change of the lithium film and the pole piece.

Optionally, the support film is a polymer film or a release film made of a polymer, wherein the polymer comprises polyolefin (polyethylene, polypropylene, polystyrene), polyester.

Optionally, the thickness of the support film is 10-100 μm, preferably 25-50 μm.

Optionally, the thickness of the ultra-thin lithium layer is 2-20 μm, preferably 2-5 μm.

Optionally, the pole piece is a negative pole piece or a positive pole piece comprising a current collector and an active material.

Optionally, the floating roll in the pair roll device is of a hollow structure.

Optionally, the floating roll in the roll pair device is under constant pressure control.

Optionally, the movement of the floating roller in the vertical direction is automatically adjusted according to the thicknesses of the lithium film and the pole piece.

Optionally, the movement of the dancer roll in the vertical direction is driven by a servo hydraulic cylinder.

The technical scheme of the invention has at least one of the following advantages:

1. the constant pressure control is adopted, so that the gap of the pair roller is perfectly matched with the thickness of the material, and the method can be suitable for pole pieces and lithium films with different thicknesses and pole pieces and lithium films with larger tolerance ranges;

2. the floating roller adopts a hollow structure, has smaller inertia and is quick in response.

Drawings

FIG. 1 is a schematic, partially enlarged cross-sectional view of a representative pole piece.

FIG. 2 is a schematic diagram of the process of the transfer coating method of the present invention.

Fig. 3 is an isometric schematic view of a transfer assembly that may be used with the present invention.

FIG. 4 is a side view of a transfer apposition device useful in the present invention after dissection of a stent.

FIG. 5 is an isometric view of the outboard lower bearing mount of FIG. 3.

Detailed Description

The following describes specific embodiments of the present invention. It is to be understood that other various embodiments can be devised and modified by those skilled in the art in light of the teachings herein without departing from the scope or spirit of the invention. The following detailed description is, therefore, not to be taken in a limiting sense.

In the description of the present invention, it is to be understood that the terms "upper", "lower", and the like are used only for convenience in describing the present invention and for simplification of description, and thus, are not to be construed as limiting the present invention.

Referring to fig. 1 and fig. 2, fig. 1 is a schematic view showing a cross section of a pole piece in a partially enlarged manner, and fig. 2 is a schematic view showing a process of a transfer lamination method. The thickness of the pole piece P is usually between 100 and 200 μm, and the common tolerance is 1-5 μm; the lithium films (L1 and L2) are typically 20-70 μm thick, with the lithium layer typically being 2-20 μm thick, and the tolerances for the lithium films (L1 and L2) typically being 1-3 μm. Therefore, there is usually a certain variation in thickness at different positions of the pole piece P, as shown in fig. 1, the thick area a and the thin area B of the pole piece may appear several times in a certain length range of the pole piece, and the thickness difference between the thick area a and the thin area B of the pole piece may reach 3-5 μm at most. Referring to fig. 2, in the transfer lamination, the pole piece P enters the roller 200 together with the upper lithium film L1 and the lower lithium film L2 and is rolled.

The conventional transfer lamination method adopts rolling equipment in a constant roll gap mode, if the roll gap is set to be larger, the lithium films (L1 and L2) corresponding to the thick area A of the pole piece can transfer and laminate the metal lithium layer on the pole piece P, and the lithium films (L1 and L2) corresponding to the thin area B of the pole piece can not transfer and laminate the metal lithium layer on the pole piece P; if the roll gap is set to be small, when the metal lithium layer corresponding to the lithium film (L1 and L2) corresponding to the thin area B part of the pole piece can be transferred to the pole piece P, the serious wrinkle phenomenon will occur to the thick area A part corresponding to the pole piece, which causes the damage of the pole piece P and influences the use.

The transfer lamination method adopts constant pressure control, and the roll gap can be quickly and automatically adapted according to the thickness of the material. When the part A of the thick area of the pole piece and the part B of the thin area of the pole piece are aimed at, the parts A and B correspond to different roll gaps respectively, but the rolling pressure can be kept constant, so that the rolling pressure of each position of the pole piece P can be ensured to be the same, and the wrinkles caused by overlarge local rolling pressure are effectively avoided on the premise of finishing the transfer laminating function.

The invention relates to a quick response transfer combination method, which comprises the following steps:

providing a lithium film, wherein the lithium film is composed of a support film and an ultrathin lithium layer; providing a pole piece, typically a negative pole piece or a positive pole piece comprising a current collector and an active material; providing a pair roller device, wherein the pair roller device comprises a fixed roller and a floating roller, the fixed roller can only rotate around the axis of the fixed roller, and the floating roller can rotate around the axis of the floating roller and can move up and down along the vertical direction; and arranging the lithium layer side of the lithium film opposite to the pole piece, and rolling by using a pair roller device together.

Specific embodiments of the fast response transition multiplexing method are described in detail below with reference to the accompanying drawings.

In the embodiment, lithium films with the same specification and thickness are adopted as the upper lithium film L1 and the lower lithium film L2, the thicknesses of the supporting films M1 and M2 are 50 μ M, the thickness of the ultrathin lithium layer is 5 μ M, and the total thickness of the lithium films is 55 μ M; the pole piece P is a negative pole piece, the current collector P0 is copper foil, the upper active material P1 and the lower active material P2 are silicon-carbon-containing active materials, and the total thickness of the pole piece P is 120 mu m.

Referring to fig. 2, the pole piece P is located in the middle of the upper lithium film L1 and the lower lithium film L2, wherein the lithium layer sides of the upper lithium film L1 and the lower lithium film L2 are disposed opposite to the pole piece P. The three layers L1 and P, L2 enter between the fixed roller 201 and the floating roller 202 of the double-roller device from top to bottom for rolling. The fixed roller 201 and the floating roller 202 are both rotated around their axes, and the floating roller 202 is applied with a constant pressure by the servo hydraulic cylinder 600.

The total thickness of the upper lithium film L1, the pole piece P and the lower lithium film L2 in the embodiment is 230 μm, and the total thickness is floated between 225 and 235 μm in consideration of the tolerance of the lithium films (L1 and L2) and the pole piece P. In the present embodiment, in order to obtain a good transfer lamination effect, the total pressure applied to the dancer 202 by the servo cylinder 600 is 30 kN. When the total thickness of the lithium films (L1 and L2) and the pole piece P is 230 mu m, constant pressure rolling is carried out under the pressure of 30 kN; when the total thickness of the lithium film (L1 and L2) and the pole piece P is 225 microns, the floating roller 202 rises rapidly under the condition of keeping 30kN constant pressure, so that the roller gap between the fixed roller 201 and the floating roller 202 is reduced instantaneously to match the total thickness of the lithium film (L1 and L2) and the pole piece P; when the total thickness of the lithium film (L1 and L2) and the pole piece P becomes thicker, for example, 235 μm, the dancer roll 202 rapidly drops while maintaining a constant pressure of 30kN, so that the roll gap between the fixed roll 201 and the dancer roll 202 momentarily increases, matching the total thickness of the current lithium film (L1 and L2) and the pole piece P. Thereby ensuring that the pressure exerted on the lithium film (L1 and L2) and the pole piece P is constant at 30kN under the condition that the total thicknesses of the lithium film (L1 and L2) and the pole piece P are different.

The quick response transfer combination method can be carried out by adopting the following quick response transfer combination device, and the quick response transfer combination device comprises the following components:

a support;

the double rollers consist of an upper roller and a lower roller which are arranged in parallel;

an upper bearing seat for mounting the upper roller;

a lower bearing seat for mounting the lower roller;

a pair roller driving device; and

the pressure thrust mechanism is arranged on the upper portion of the main body,

the upper bearing seat is fixedly connected with the bracket, and the lower bearing seat is movably connected with the bracket and can move along the vertical direction; the pair roller driving device is used for driving the upper roller and the lower roller to rotate; the pressure thrust mechanism is used for driving the lower roller to move along the vertical direction.

Optionally, the lower bearing seat comprises a bearing seat main body and needle roller plates, and the needle roller plates are arranged on two sides of the bearing seat main body; and a bearing seat lining plate is arranged on the support and opposite to the lower bearing seat, and the bearing seat lining plate is in contact with the needle roller plate on the bearing seat and is in rolling friction with the needle roller plate.

Optionally, the lower bearing seat is axially fixed by an end baffle assembly, an end baffle bearing is arranged in the end baffle assembly, and the bearing is in contact with the bearing seat and is in rolling friction with the bearing seat.

Optionally, the pair of rollers is a hollow structure.

Optionally, only the lower roller of the pair of rollers is of a hollow structure.

Optionally, the pair roller driving device comprises a motor and a speed reducer.

Optionally, the pair roller driving device comprises two sets of motors and speed reducers, and the motors and the speed reducers are respectively used for driving the upper roller and the lower roller.

Optionally, the pressure thrust mechanism is a servo hydraulic cylinder.

Optionally, the stand is of a detachable construction.

Optionally, the stent comprises a medial stent, a lateral stent, and connecting columns and connecting blocks for connecting the medial stent and the lateral stent.

Optionally, both the upper and lower rolls have an internal hollow structure, and smaller journals that meet strength requirements.

Optionally, the upper bearing housing is divided into an inner upper bearing housing and an outer upper bearing housing, both of which are journalled at both ends of the upper roller by bearings and then fixedly connected to the bracket.

Optionally, the lower bearing seat is divided into an inner lower bearing seat and an outer lower bearing seat, and the inner lower bearing seat and the outer lower bearing seat are both connected with the shaft necks at the two ends of the lower roller through bearings; the bearing seat further comprises a bearing seat main body and needle rolling plates, the needle rolling plates are arranged on two sides of the bearing seat main body, and the other sides of the needle rolling plates are in contact with bearing seat lining plates on the support.

Optionally, the upper roller is of a common solid structure, and the lower roller which only has the function of moving in the vertical direction is of a hollow structure, so that the characteristics of low weight and low inertia are ensured.

Optionally, the upper bearing seat and the lower bearing seat have smaller volume to meet the strength requirement, so the bearing seats also have the characteristics of low weight and low inertia.

Alternatively, only the roller moving in the vertical direction is of a hollow structure, and the bearing seat is of a small size, so that the roller bearing has the characteristics of low weight and low inertia.

Referring to fig. 3, 4 and 5, one exemplary fast response transfer multiplexing device that may be used with the present invention includes:

the bracket 100 is of a detachable structure and comprises an inner bracket 101, an outer bracket 102, a connecting column 103 and a connecting block 104, wherein the connecting column 103 is used for connecting the inner bracket 101 and the outer bracket 102; bearing seat lining plates 110 are arranged on the inner side bracket 101 and the outer side bracket 102 at positions opposite to lower bearing seats (420 and 410);

the double-roller 200 comprises an upper roller 201 and a lower roller 202, wherein the upper roller 201 and the lower roller 202 both have internal hollow structures and smaller journals meeting strength requirements; in some embodiments, only the lower roller 202 may be an internal hollow structure.

An upper bearing housing 300 divided into an inner upper bearing housing 310 and an outer upper bearing housing 320, both of which are connected to journals at both ends of the upper roll by bearings and then fixedly connected to the bracket 100;

a lower bearing seat 400 divided into an inner lower bearing seat 410 and an outer lower bearing seat 420, both of which are connected with journals at both ends of the lower roll through bearings; the lower bearing housing 400 further includes a housing body 401 and needle plates 402, the needle plates 402 being disposed at both sides of the housing body 401, the other sides of the needle plates 402 being in contact with the housing liner 110 on the bracket 100; the bearing block liner 110 is fixedly connected to the bracket 100;

the pair roller driving device 500 comprises an upper roller driving motor 511, an upper roller speed reducer 512, a lower roller driving motor 521 and a lower roller speed reducer 522, wherein the upper roller driving motor 511 drives the upper roller 201 to rotate after speed reduction through the upper roller speed reducer 512, and the lower roller driving motor 521 drives the lower roller 202 to rotate after speed reduction through the lower roller speed reducer 522; in some other embodiments, the pair-roller driving device 500 may only include one set of driving motor and speed reducer, where the speed reducer is a dual output shaft for driving the upper roller 201 and the lower roller 202 to rotate simultaneously;

the pressure thrust mechanism 600 is configured to drive the inner lower bearing housing 410 and the outer lower bearing housing 420 to move in the vertical direction, in this embodiment, the pressure thrust mechanism 600 is a hydraulic servo cylinder, and in some embodiments, a servo electric cylinder, a gas-liquid pressure boost cylinder, an electro-hydraulic servo cylinder, or the like may be used.

In some embodiments, axial retention of lower bearing housing 400 is achieved using bearing housing end baffle assembly 430; the bearing seat end baffle assembly 430 comprises an end baffle body 431, an end baffle bearing 432 and a bearing fixing shaft 433, wherein a groove is formed in the end baffle body 431, the end baffle bearing 432 is arranged in the groove and is fixed by the bearing fixing shaft 433, and the outer circular surface of the fixed end baffle bearing 432 slightly protrudes out of the end baffle body 431; thus, there is rolling friction between the bearing housing body 401 and the bearing housing end stop assembly 430 with minimal frictional resistance.

In some embodiments, both the upper roll chock 300 and the lower roll chock 400 are of a relatively small volume construction meeting strength requirements, with minimal weight and inertia; in some embodiments, only the lower roll chock 400 may be of a smaller volume construction.

In the invention, the lower roller bearing seat 400 and the lower roller 202 have extremely small weight and motion inertia, and the structure of the roller plate 402 and the bearing seat end baffle plate assembly 430 reduces the running resistance of the bearing seat in the working process, thereby ensuring that the lower roller 202 can rapidly move in the vertical direction according to the thickness of materials in the running process of the transfer combination device and realizing rapid response.

Although the present invention has been disclosed above, the present invention is not limited thereto. Various changes and modifications may be effected therein by one skilled in the art without departing from the spirit and scope of the invention as defined in the appended claims.

Claims

1. A fast response transfer compounding method, comprising:

providing a lithium film, wherein the lithium film is composed of a support film and an ultrathin lithium layer with the thickness of 2-20 μm, the ultrathin lithium layer side of the lithium film is called a lithium layer side, and the opposite support film side of the lithium film is called a thin film side;

providing a pole piece;

providing a pair roller device, wherein the pair roller device comprises a fixed roller and a floating roller which are oppositely arranged up and down, the fixed roller can only rotate around the axis of the fixed roller, and the floating roller can rotate around the axis of the floating roller and can also move up and down along the vertical direction;

and arranging the lithium layer side of the lithium film opposite to the pole piece, and rolling by using a roller device, wherein the floating roller moves in the vertical direction and automatically adjusts in response to the thickness change of the lithium film and the pole piece.

2. The rapid response transfer lamination process of claim 1 wherein the support film is a polymeric film or a release film made from a polymer comprising a polyolefin, a polyester.

3. The rapid response transfer lamination process of claim 2 wherein the polyolefin comprises polyethylene, polypropylene, polystyrene.

4. The rapid response transfer cladding method of claim 1, wherein the thickness of the ultra-thin lithium layer is 2-5 μ ι η.

5. The rapid response transfer lamination process of claim 1, wherein the pole piece is a negative pole piece or a positive pole piece comprising a current collector and an active material.

6. The rapid response transfer lamination method of claim 1, wherein the floating roll in the pair roll apparatus is a hollow structure.

7. The rapid response transfer lamination method of claim 1 wherein the dancer roll in the counter roll apparatus is under constant pressure control.

8. The rapid response transfer lamination method of claim 1 wherein the vertical movement of the dancer is driven by a servo hydraulic cylinder.