WO2021000492A1

WO2021000492A1 - Method for preparing lithium battery

Info

Publication number: WO2021000492A1
Application number: PCT/CN2019/117832
Authority: WO
Inventors: 张聪聪; 王卫润东
Original assignee: 萨姆蒂萨（天津）数据信息技术有限公司
Priority date: 2019-07-02
Filing date: 2019-11-13
Publication date: 2021-01-07
Also published as: CN110459813A; CN110459813B

Abstract

Disclosed is a method for preparing a lithium battery, comprising: providing an insulation film; preparing at least one first electrode layer on the insulation film by means of film-coating with a first conductive metal and applying a first slurry; preparing an isolation application film on the first electrode layer by means of applying a second slurry; preparing at least one second electrode layer on the isolation application film by means of applying a third slurry and film-coating a second conductive metal; and folding the insulation film and the prepared first electrode layer isolation application film and second electrode layer, and soaking same in an electrolyte, and then curing and packaging same to obtain the lithium battery. The invention solves the problem that a breakthrough in the material performance is difficult during the lithium battery preparation process, and the lithium battery cannot meet the requirements of a high energy density, a high power density, and a long cycle lifetime.

Description

Method for preparing lithium battery

Technical field

The invention relates to the technical field of lithium batteries, in particular to a method for preparing lithium batteries.

Background technique

As the number of mobile terminals continues to increase, as one of the core components of mobile terminals, the demand for batteries is also getting higher and higher. At present, the energy of the battery configured in the mobile terminal is generally low, and a mobile power supply (also called a power bank) is often required to supplement the battery of the mobile terminal. The sustainable energy of ion batteries is about 230wh/kg and the energy density is about 600wh/L, which cannot meet the requirements of high energy density, high power density, and long cycle life. And the performance of the battery is mainly determined by the material. The technical breakthrough of the material is very difficult, the cycle is very long, and it is not conducive to meeting the battery requirements of high energy density, high power density, and long cycle life.

Summary of the invention

In order to solve the above technical problems, the present invention provides a method for preparing a lithium battery, which solves the difficulty of material performance breakthrough in the lithium battery preparation process, and the lithium battery cannot meet the requirements of high energy density, high power density, and long cycle life.

The embodiment of the present invention provides a method for preparing a lithium battery, including:

Provide an insulating film;

At least one first electrode layer is prepared on the insulating film by using the first conductive metal for coating and the first slurry for wiping and pressing;

Using the second slurry to wipe and press, prepare an isolation wipe press film on the first electrode layer;

At least one second electrode layer is prepared on the isolation wiping film by using the third slurry for wiping and the second conductive metal for coating;

The insulating film and the prepared first electrode layer, the isolation wipe pressing film and the second electrode layer are folded, and the electrolyte is soaked, and then solidified and packaged to obtain a lithium battery.

Optionally, the preparation of at least one first electrode layer on the insulating film by using the first conductive metal for coating and the first slurry for wiping and pressing includes:

Vapor-depositing a first conductive metal on the insulating film or the first electrode layer by vacuum evaporation or magnetron sputtering to obtain a first current collector film;

The first slurry with a weight solid content of 55-90% and a viscosity of 3500-15000 cP is wiped and pressed on the first current collector film to obtain a first wiped press film.

Optionally, the thickness of the first current collector film ranges from 0.5 to 10 μm.

Optionally, the thickness of the first application film ranges from 3 to 70 μm.

Optionally, the method of using the second slurry to wipe and press to prepare an isolation wipe and press film on the first electrode layer includes:

A second slurry with a solid content of 5-50% by weight and a viscosity of 500-6000 cP is wiped and pressed on the first electrode layer to obtain an isolation wipe press film.

Optionally, the thickness of the isolation wipe pressing film ranges from 3 to 15 um.

Optionally, the method of using a third slurry for wipe pressing and a second metal for coating to obtain at least one second electrode layer on the isolation wipe pressing film includes:

Applying a third slurry with a weight solid content of 55 to 90% and a viscosity of 3500 to 15000 cP on the isolation wipe press film or the second electrode layer to obtain a second wipe press film;

The second conductive metal is vapor-deposited on the second wiped film by vacuum evaporation or magnetron sputtering to obtain a second current collector film.

Optionally, the thickness of the second current collector film ranges from 0.5 to 10 μm.

Optionally, the thickness of the second application film is in the range of 3 to 70 μm.

Optionally, the preparation method of the lithium battery further includes at least one of the following:

The negative electrode material is stirred by a planetary propeller at a temperature of 30-50°C to prepare the negative electrode slurry;

The positive electrode material is stirred by a planetary propeller at a temperature of 30 to 50°C to prepare a positive electrode slurry;

The isolation raw material is stirred by a planetary propeller at a temperature of 30-50°C to prepare the second slurry;

Wherein, the first slurry is one of the positive electrode slurry and the negative electrode slurry, and the third slurry is the other one of the positive electrode slurry and the negative electrode slurry.

Optionally, the insulating film and the prepared first electrode layer, the isolation wipe press film, and the second electrode layer are folded, and the electrolyte is soaked, and then solidified and packaged to obtain a lithium battery, include:

Fold the insulating film and the prepared first electrode layer, the isolation wipe press film, and the second electrode layer, and after soaking in the electrolyte solution for 0 to 4 hours in a vacuum state, at 60 to 100°C The lithium battery is obtained by curing and molding under pressure at a temperature of 0-2 MPa and packaging.

The beneficial effects of the embodiments of the present invention are:

In the above scheme, the first electrode layer, the isolation wipe pressure film and the second electrode layer are prepared by means of metal plating and paste wipe pressure to ensure that the insulation film and the first electrode layer are between the insulating film and the first electrode layer. Between and the isolation wiping film, between the isolation wiping film and the second electrode layer, between at least two of the first electrode layers, and between at least two of the second electrode layers, Adopt atom or molecular adsorption type gapless contacts, which greatly improves the stability of the battery during charging and discharging, greatly reduces the intermediary substances, reduces the conductive internal resistance, and solves the problem of low specific energy, low energy density, and low energy density of lithium-ion batteries. The problems of low specific power, low power density, poor safety performance, fewer cycles, narrow operating temperature range, high kWh investment density, and long production cycle.

Description of the drawings

Figure 1 shows a flow chart of a method for preparing a lithium battery according to an embodiment of the present invention;

Figure 2 shows one of the structural schematic diagrams of a lithium battery according to an embodiment of the present invention;

FIG. 3 shows the second structural diagram of a lithium battery according to an embodiment of the present invention;

Figure 4 shows one of the schematic diagrams of the wiper pressing device of the embodiment of the present invention;

Fig. 5 shows the second schematic diagram of the wiping and pressing device according to the embodiment of the present invention.

Detailed ways

Hereinafter, exemplary embodiments of the present invention will be described in more detail with reference to the accompanying drawings. Although exemplary embodiments of the present invention are shown in the drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to enable a more thorough understanding of the present invention and to fully convey the scope of the present invention to those skilled in the art.

As shown in Figure 1, an embodiment of the present invention provides a method for preparing a battery, including:

Step 11: Provide an insulating film.

Optionally, the insulating film can be a polyethylene terephthalate (PET) film with a thickness ranging from 8 to 15 μm.

Step 12: At least one first electrode layer is prepared on the insulating film by using the first conductive metal for coating and the first slurry for wiping.

Optionally, the above step 12 may specifically include:

The first slurry with a weight solid content of 55 to 90% and a viscosity of 3500 to 15000 cP is wiped and pressed on the first current collector film to obtain a first wipe press film to reduce contact resistance caused by various welding.

Optionally, the thickness of the first current collector film ranges from 0.5 to 10 μm. The thickness of the first wiping press film ranges from 3 to 70 μm.

For example: when the first electrode layer is used as the negative electrode, pure copper (Cu) can be vapor-deposited on the insulating film by vacuum evaporation or magnetron sputtering to obtain the negative electrode current collector film; The 360mAh/g artificial graphite with a content of 55-90% and a viscosity of 3500-15000 cP is applied and baked on the negative electrode current collector film to form a negative electrode wipe pressure film.

Optionally, when there are multiple first electrode layers, the first conductive metal is vapor deposited on the insulating film by vacuum evaporation or magnetron sputtering to obtain a first-level first current collector Film; then the first slurry with a weight solid content of 55 to 90% and a viscosity of 3500 to 15000 cP is wiped and pressed on the first current collector film of the first stage to obtain the first wipe pressure film of the first stage, Thus, the first electrode layer of the first level is obtained.

Further, the first conductive metal is vapor-deposited on the first electrode layer of the first stage by vacuum evaporation or magnetron sputtering to obtain the first current collector film of the second stage; then the weight solid content The first slurry with a viscosity of 55 to 90% and a viscosity of 3500 to 15000 cP is wiped and pressed on the first current collector film of the second stage to obtain the first wipe press film of the second stage, thereby obtaining the second pressure film of the second stage One electrode layer; and so on, so that multiple first electrode layers can be prepared.

Step 13: Using the second slurry to wipe and press, prepare an isolation wipe and press film on the first electrode layer.

Optionally, the above step 13 may specifically include:

For example, a polyvinylidene fluoride (PVDF) with a weight solid content of 5-50% and a viscosity of 500-6000 cP is wiped and baked to form an isolation wiped film on the first electrode layer.

Step 14: At least one second electrode layer is prepared on the isolation wiping film by using the third slurry for wiping and the second conductive metal for coating.

Optionally, the foregoing step 14 may specifically include:

The second conductive metal is vapor-deposited on the second wiped film by vacuum evaporation or magnetron sputtering to obtain a second current collector film to reduce contact resistance caused by various welding.

For example: when the second electrode layer is used as the positive electrode, 163mAh/g NCM622 with a weight solid content of 55 to 90% and a viscosity of 3500 to 15000 cP can be wiped and baked to form a positive electrode wipe on the separator wiper film. After pressing the film, pure aluminum (Al) is vapor-deposited on the second pressing film by vacuum evaporation or magnetron sputtering to obtain a positive electrode current collector film.

Optionally, when there are multiple second electrode layers, a third slurry with a weight solid content of 55 to 90% and a viscosity of 3500 to 15000 cP is first wiped and pressed on the isolation wipe press film, Obtain the first-level second wipe press film; then use vacuum evaporation or magnetron sputtering to vapor-deposit the second conductive metal on the first-level second wipe press film to obtain the first-level second press film Two current collector films, thereby obtaining the first-level second electrode layer.

Further, a third slurry with a weight solid content of 55 to 90% and a viscosity of 3500 to 15000 cP is wiped and pressed on the second current collector film of the first stage to obtain the second Wipe the film; then use vacuum evaporation or magnetron sputtering to vapor-deposit a second conductive metal on the second level of the second wipe press film to obtain the second level of the second current collector film, thereby obtaining The second electrode layer of the second level, and so on, so that multiple second electrode layers can be prepared.

Step 15: Fold the insulating film, the prepared first electrode layer, the isolation wipe press film and the second electrode layer, and after soaking in electrolyte, curing and packaging to obtain a lithium battery.

Optionally, the above step 15 may specifically include:

Specifically, it can be folded into: capacity 8400mAh, size 6mm*65mm*80mm according to the size of the lithium battery to be prepared (such as length, width, height) and battery capacity and voltage requirements; then immerse in the electrolysis under vacuum After being in the liquid for 0 to 4 hours, in a temperature environment of 60 to 100° C. under pressure of 0 to 2 MPa, solidified and molded, then packaged in an aluminum plastic film to obtain a lithium battery.

Optionally, after packaging, processes such as battery formation, battery high temperature aging, battery shaping, and room temperature aging can be performed in sequence to obtain a lithium battery.

In this way, the lithium battery manufactured according to the above process has a capacity of 8400mAh, a size of 6mm*65mm*80mm, a specific energy of 330-350wh/kg, an energy density of 1000-1500wh/L, a cycle life of 1500, and a cyclic state of charge ( The State of Charge (SOC) reaches 85% or more, and the safety performance of puncture and extrusion will not catch fire or explode.

Optionally, the method for preparing the lithium battery may further include at least one of the following:

As shown in Fig. 2 and Fig. 3, for the lithium battery prepared by the above preparation method, the preparation method of the lithium battery according to the embodiment of the present invention will be described in detail below:

The preparation process of the lithium battery according to the embodiment of the present invention includes: material baking, computer batching, high-viscosity mixing pulping, metal vacuum coating, wiping and pressing into film, wiping and pressing film folding, folding and wiping and pressing film immersion liquid curing and packaging, Composite wipe press film battery formation, composite wipe press film battery high temperature aging, composite wipe press film battery shaping and room temperature aging, composite wipe press film battery screening and storage.

The process parameters include at least: the solid content and viscosity of the positive/negative electrode slurry, the thickness of the wiping film, the angle of the wiping tool, and the curing temperature of the immersion liquid of the folded wiping film.

The preparation process of the above-mentioned lithium battery is described in detail below in combination with specific parameters:

The planetary propeller stirring method is used in advance, the stirring temperature is controlled in the range of 40±10℃, the weight solid content is 55 to 90%, and the viscosity is 3500 to 15000 cP to obtain high-viscosity positive and negative electrode slurry; and the planetary propeller stirring method is used to control the stirring temperature In the range of 40±10℃, the weight solid content is 5-50%, the viscosity is 500-6000cP, and the high-viscosity isolation slurry is obtained;

Provide an insulating film 21, the material can be PET material;

Conductive metals such as Cu or Ni are vapor-deposited on the insulating film 21 by vacuum evaporation or magnetron sputtering, etc., to obtain a negative current collector film 22 with a thickness of 0.5-10 μm;

Then use the wiper pressing device shown in FIG. 2 to wipe and press the negative electrode slurry on the negative electrode current collector film 22 to obtain a negative electrode wiper film 23 with a thickness of 3 to 70 μm; the separator slurry is wiped and pressed on the negative electrode wiper film 23 To obtain a spacer wipe press film 24 with a thickness of 3-15um; wipe and press the positive electrode slurry on the spacer wipe press film 24 to obtain a positive electrode wipe press film 25 with a thickness of 3～70um;

Then, conductive metal such as Al is vapor-deposited on the positive electrode wiped film 25 by vacuum evaporation or magnetron sputtering, etc., to obtain a positive electrode current collector film 26 with a thickness of 0.5-10 μm;

Fold according to the size of the designed battery and battery capacity and voltage requirements; soak the folded composite wiper film in the electrolyte for 0～4h under normal pressure or vacuum, and then put the composite wiper film at 60～100℃ after soaking After being cured and molded under pressure of 0-2MPa in the environment, it is encapsulated in an aluminum plastic film; then a lithium battery is formed after the processes of battery formation, battery high temperature aging, battery shaping, and room temperature aging.

Optionally, the positive/negative ear connection of the lithium battery in this embodiment is realized by conductive metal vapor deposition coating to reduce contact resistance caused by various welding.

Specifically, the wiping and pressing device shown in FIGS. 4 and 5 includes: a wiping and pressing platform 41, a wiping die 42, and a wiping tool 43; wherein the wiping and pressing platform 41 is fixed on the equipment foundation, and the wiping and pressing platform 41 can be used 304 stainless steel flat plate; the wiping die 42 is pressed and fixed on the wiping platform 41, the wiping die 42 can be made of 304 stainless steel sheet; the wiping tool 43 can be a polyethylene scraper; the wiping tool 43 is in contact with the wiping die 42 and passes Move left and right to wipe and press out the wipe press film 44 (for example, positive electrode wipe press film, negative electrode wipe press film, or isolation wipe press film). Optionally, the included angle between the left and right movement directions of the wiping tool 43 is 0-90°.

In the description of the present invention, the terms "first" and "second" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of these features. In the description of the present invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise specifically defined.

The above are the preferred embodiments of the present invention. It should be pointed out that for those of ordinary skill in the art, several improvements and modifications can be made without departing from the principles of the present invention, and these improvements and modifications are also included in the present invention. Within the scope of protection of the invention.

Claims

A method for preparing a lithium battery, characterized in that it comprises:

Provide an insulating film;

At least one first electrode layer is prepared on the insulating film by using the first conductive metal for coating and the first slurry for wiping and pressing;

Using the second slurry to wipe and press, prepare an isolation wipe press film on the first electrode layer;

At least one second electrode layer is prepared on the isolation wiping film by using the third slurry for wiping and the second conductive metal for coating;

The insulating film and the prepared first electrode layer, the isolation wipe pressing film and the second electrode layer are folded, and the electrolyte is soaked, and then solidified and packaged to obtain a lithium battery.
The method for preparing a lithium battery according to claim 1, wherein the first conductive metal is used for coating and the first slurry is used for wiping, and at least one first electrode is prepared on the insulating film Layers, including:

Vapor-depositing a first conductive metal on the insulating film or the first electrode layer by vacuum evaporation or magnetron sputtering to obtain a first current collector film;

The first slurry with a weight solid content of 55-90% and a viscosity of 3500-15000 cP is wiped and pressed on the first current collector film to obtain a first wiped press film.
The method for manufacturing a lithium battery according to claim 2, wherein the thickness of the first current collector film is in the range of 0.5-10 μm.
The method for manufacturing a lithium battery according to claim 2, wherein the thickness of the first wipe press film ranges from 3 to 70 μm.
The method for manufacturing a lithium battery according to claim 1, wherein the step of using a second slurry for wiping and pressing to prepare an isolation wipe and pressing film on the first electrode layer comprises:

A second slurry with a solid content of 5-50% by weight and a viscosity of 500-6000 cP is wiped and pressed on the first electrode layer to obtain an isolation wipe press film.
The method for preparing a lithium battery according to claim 5, wherein the thickness of the isolation wipe press film is in the range of 3-15um.
The method for preparing a lithium battery according to claim 1, wherein the third slurry is used for wiping and the second metal is coated, and at least one second is prepared on the isolation wiping film. Electrode layer, including:

Applying a third slurry with a weight solid content of 55 to 90% and a viscosity of 3500 to 15000 cP on the isolation wipe press film or the second electrode layer to obtain a second wipe press film;

The second conductive metal is vapor-deposited on the second wiped film by vacuum evaporation or magnetron sputtering to obtain a second current collector film.
8. The method for manufacturing a lithium battery according to claim 7, wherein the thickness of the second current collector film is in the range of 0.5-10 μm.
7. The method for manufacturing a lithium battery according to claim 7, wherein the thickness of the second wipe press film is in the range of 3 to 70 μm.
The method for preparing a lithium battery according to any one of claims 1 to 9, characterized in that it further comprises at least one of the following:

The negative electrode material is stirred by a planetary propeller at a temperature of 30-50°C to prepare the negative electrode slurry;

The positive electrode material is stirred by a planetary propeller at a temperature of 30 to 50°C to prepare a positive electrode slurry;

The isolation raw material is stirred by a planetary propeller at a temperature of 30-50°C to prepare the second slurry;

Wherein, the first slurry is one of the positive electrode slurry and the negative electrode slurry, and the third slurry is the other one of the positive electrode slurry and the negative electrode slurry.