阅读说明：本技术 一种极片及其制备方法 (Pole piece and preparation method thereof ) 是由 臧世伟 于 2021-02-04 设计创作，主要内容包括：本发明涉及锂电池技术领域,具体涉及一种极片及其制备方法,本发明的极片包括导电基膜、设于导电基膜两相对面的金属层、设于两金属层远离导电基膜一面的第一活性材料层、设于两第一活性材料层远离金属层一面的补锂层和设于两补锂层远离第一活性材料层一面的第二活性材料层。本发明的极片的制备方法,包括制备导电基膜；在导电基膜的两相对面上镀金属层；在两金属层远离导电基膜的表面涂覆第一活性浆料；在两第一活性材料层远离金属层的表面镀补锂层；在两补锂层远离第一活性材料层的表面涂覆第二活性浆料,制得极片。本发明的极片降低了电池内阻,减少了电池发热的可能性。(The invention relates to the technical field of lithium batteries, in particular to a pole piece and a preparation method thereof. The preparation method of the pole piece comprises the steps of preparing a conductive base film; plating metal layers on two opposite surfaces of the conductive base film; coating first active slurry on the surfaces of the two metal layers far away from the conductive base film; plating a lithium supplementing layer on the surfaces of the two first active material layers far away from the metal layer; and coating the second active slurry on the surfaces of the two lithium supplementing layers far away from the first active material layer to obtain the pole piece. The pole piece reduces the internal resistance of the battery and reduces the possibility of battery heating.)

1. A pole piece, characterized by: the lithium ion battery comprises a conductive base film, metal layers arranged on two opposite surfaces of the conductive base film, first active material layers arranged on two metal layers and far away from one surface of the conductive base film, lithium supplement layers arranged on two first active material layers and far away from one surface of the metal layers, and second active material layers arranged on two lithium supplement layers and far away from one surface of the first active material layers.

2. A preparation method of a pole piece is characterized by comprising the following steps: the method comprises the following steps:

step one, preparing a conductive base film;

mixing a high-molecular base material, an electronic conductor, diisocyanate and conductive carbon black, and preparing the mixture of the materials into a conductive base film by adopting film manufacturing equipment;

plating metal layers on two opposite surfaces of the conductive base film by adopting a vacuum coating technology;

coating first active slurry on the surfaces of the two metal layers far away from the conductive base film, and drying to form a first active material layer;

plating a lithium supplementing layer on the surfaces of the two first active material layers far away from the metal layer by adopting a vacuum coating technology;

and fifthly, coating second active slurry on the surfaces, far away from the first active material layer, of the two lithium supplement layers to form a second active material layer, and obtaining the pole piece.

3. The preparation method of the pole piece according to claim 2, characterized in that: the conductive basal membrane comprises the following components in parts by weight: 40-50 parts of high molecular base material, 20-30 parts of electronic conductor, 5-10 parts of diisocyanate and 10-20 parts of conductive carbon black.

4. The preparation method of the pole piece according to claim 2, characterized in that: the polymer base material is PP particles, PET particles or PE particles.

5. The preparation method of the pole piece according to claim 2, characterized in that: the electronic conductor is copper particles or aluminum particles.

6. The preparation method of the pole piece according to claim 2, characterized in that: the metal layer is a copper layer or an aluminum layer.

7. The preparation method of the pole piece according to claim 2, characterized in that: the lithium supplementing layer is a metal lithium layer.

8. The preparation method of the pole piece according to claim 2, characterized in that: the thickness of the metal lithium layer is 100-300 nm.

9. The preparation method of the pole piece according to claim 2, characterized in that: the first active paste includes 10-20% of an active material, 20-30% of a conductive agent, and 50-60% of a binder.

10. The preparation method of the pole piece according to claim 2, characterized in that: the second active paste includes 60-70% of an active material, 10-20% of a binder, and 10-20% of a conductive agent.

Technical Field

The invention relates to the technical field of lithium batteries, in particular to a pole piece and a preparation method thereof.

Background

Along with the development of society, people have higher and higher requirements on energy, the prior fossil energy can meet the requirements of people, and nowadays, along with the rise of electronic equipment, people pay more and more attention to the use of clean energy, and the most important of the clean energy is a lithium ion battery.

Disclosure of Invention

In order to overcome the defects of the prior art, the first object of the invention is to provide a pole piece which has the advantages of reducing the internal resistance of a battery and reducing the possibility of heat generation of the battery.

The second purpose of the invention is to provide a preparation method of the pole piece, which is simple, and the prepared pole piece has the advantages of reducing the internal resistance of the battery and reducing the possibility of battery heating.

The first purpose of the invention is realized by the following technical scheme:

the utility model provides a pole piece, its includes the electrically conductive base film, locate the double-phase opposite metal level of electrically conductive base film, locate two metal levels and keep away from the first active material layer of electrically conductive base film one side, locate two first active material layers and keep away from the mend lithium layer of metal level one side and locate two mend lithium layer and keep away from the second active material layer of first active material layer one side.

The second purpose of the invention is realized by the following technical scheme:

a preparation method of a pole piece comprises the following steps:

step one, preparing a conductive base film;

mixing a high molecular base material, an electronic conductor, diisocyanate and conductive carbon black, and preparing the mixture of the materials into a conductive base film by adopting film manufacturing equipment, wherein the equipment for manufacturing the film can be a casting film machine and a calender, and can also be other equipment capable of manufacturing the film;

plating metal layers on two opposite surfaces of the conductive base film by adopting a vacuum coating technology; specifically, the vacuum coating technology adopts magnetron sputtering equipment or vacuum evaporation equipment.

Coating first active slurry on the surfaces of the two metal layers far away from the conductive base film, and drying for 10-15min at the temperature of 60-80 ℃ to form a first active material layer;

plating a lithium supplementing layer on the surfaces of the two first active material layers far away from the metal layer by adopting a vacuum coating technology; specifically, the vacuum coating technology adopts magnetron sputtering equipment or vacuum evaporation equipment.

And fifthly, coating second active slurry on the surfaces, far away from the first active material layer, of the two lithium supplement layers to form a second active material layer, and obtaining the pole piece.

Wherein the thickness of the conductive base film is 1-2 microns.

The conductive base film comprises the following components in parts by weight: 40-50 parts of high molecular base material, 20-30 parts of electronic conductor, 5-10 parts of diisocyanate and 10-20 parts of conductive carbon black.

Wherein the polymer base material is PP particles, PET particles or PE particles. The electronic conductor is copper particles or aluminum particles. The particle diameter of the electronic conductor is 4-15 nm.

Wherein the metal layer is a copper layer or an aluminum layer. The thickness of the metal layer is 1-2 microns.

Wherein, the lithium supplement layer is a metal lithium layer. The thickness of the lithium supplement layer is 100-300 nm.

Wherein the first active material layer has a higher conductivity than the second active material layer.

Wherein the thickness of the first active material layer is 1-2 microns; the thickness of the second active material layer is 10 to 70 micrometers.

Wherein the first active paste comprises 10-20% of active material, 20-30% of conductive agent and 50-60% of binder. The second active paste includes 60-70% of an active material, 10-20% of a binder, and 10-20% of a conductive agent.

The conductive agent is at least one of acetylene black, Ketjen black, conductive graphite and conductive carbon fiber.

The binder is at least one of styrene-butadiene latex, polytetrafluoroethylene and polyethylene oxide.

When the metal layer is a copper layer, the active material is at least one of lithium titanate and graphite.

When the metal layer is an aluminum layer, the active material is at least one of lithium iron phosphate, lithium cobaltate and lithium nickel cobalt manganese oxide.

The invention has the beneficial effects that:

the pole piece of the invention adopts the conductive base film with conductive performance, so that when the pole piece is used in energy storage equipment, such as a lithium ion battery, the internal resistance of the lithium ion battery can be reduced, and the possibility of battery heating is reduced. Through the setting of first, second active material layer, strengthened the intensity of pole piece on the one hand, prevent the production of lithium dendrite, the proportion of battery active material has also been increased in the setting of multilayer active material, when being applied to among the lithium ion battery, has also increased lithium ion battery's energy density, and the setting of mending the lithium layer not only can supply the lithium source for lithium ion battery in addition, increases the energy density of battery, can further strengthen the electric conductive property of pole piece moreover, further reduces the possibility that the battery generates heat.

According to the novel pole piece prepared by the preparation method, the electronic conductor is added into the film base material, the anode material containing the binder and the conductive agent is arranged between the metal layer and the second active material layer, the conductivity of the film base material is increased, the internal resistance of the battery is reduced, the possibility of heating of the battery is reduced, and the lithium metal layer is arranged on the first active material layer, so that lithium ions consumed by the lithium ion battery in the operation process can be compensated, and the energy density of the lithium ion battery is increased.

Drawings

The invention is further illustrated with reference to the following figures and examples.

FIG. 1 is a side view of a pole piece of the present invention.

Description of reference numerals: 1. a conductive base film; 2. a metal layer; 3. a first active material layer; 4. a lithium supplement layer; 5. a second active material layer.

Detailed Description

The conception, the specific structure, and the technical effects produced by the present invention will be clearly and completely described below in conjunction with the embodiments and the accompanying drawings to fully understand the objects, the features, and the effects of the present invention. It is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments, and those skilled in the art can obtain other embodiments without inventive effort based on the embodiments of the present invention, and all embodiments are within the protection scope of the present invention. In addition, all the connection/connection relations referred to in the patent do not mean that the components are directly connected, but mean that a better connection structure can be formed by adding or reducing connection auxiliary components according to specific implementation conditions. All technical characteristics in the invention can be interactively combined on the premise of not conflicting with each other.

Example 1

A pole piece is shown in figure 1, and comprises a conductive base film 1, metal layers 2 arranged on two opposite surfaces of the conductive base film 1, first active material layers 3 arranged on one surfaces, far away from the conductive base film 1, of the two metal layers 2, lithium supplement layers 4 arranged on one surfaces, far away from the metal layers 2, of the two first active material layers 3, and second active material layers 5 arranged on one surfaces, far away from the first active material layers 3, of the two lithium supplement layers 4.

The pole piece of the invention adopts the conductive base film 1 with conductive performance, so that when the pole piece is used in energy storage equipment, such as a lithium ion battery, the internal resistance of the lithium ion battery can be reduced, and the possibility of battery heating is reduced. The first active material layer 3 is arranged on the surface of the metal layer 2, so that on one hand, the strength of the pole piece can be enhanced, the generation of lithium dendrites can be prevented, and when the pole piece provided by the invention is applied to a lithium ion battery, the energy density of the lithium ion battery is also improved due to the arrangement of the double-layer active material. The arrangement of the lithium supplement layer 4 can supplement a lithium source for the lithium ion battery, so that the energy density of the battery is increased, the conductivity of the pole piece can be further enhanced, and the possibility of heating of the battery is further reduced.

The conductive base film 1 comprises a film base material, and an electronic conductor and conductive carbon black which are uniformly arranged on the film base material. The electronic conductor and the conductive carbon black are uniformly arranged on the film base material, so that the conductivity of the conductive base film 1 is improved, the internal resistance of the lithium ion battery is reduced, and the possibility of battery heating is reduced.

Wherein, the thickness of the conductive basal membrane 1 is 1-2 microns.

Wherein, the film substrate is a PP film, a PE film or a PET film.

Wherein the electronic conductor is copper particles or aluminum particles. The copper particles and the aluminum particles have good conductivity, so that the internal resistance of the lithium ion battery is reduced, and the heat generation of the battery is reduced.

Wherein the particle diameter of the electronic conductor is 4-15 nm.

The metal layer 2 is a copper layer or an aluminum layer, and has good conductivity, so that the internal resistance of the lithium ion battery is reduced, and the heat generation of the battery is reduced.

Wherein the thickness of the metal layer 2 is 1-2 microns.

Wherein, the lithium supplement layer 4 is a metal lithium layer.

Wherein the thickness of the lithium-supplementing layer 4 is 100-300 nm.

Wherein the first active material layer 3 has a higher conductivity than the second active material layer 5.

Wherein the thickness of the first active material layer 3 is 1-2 microns, and the thickness of the second active material layer 5 is 10-70 microns.

Example 2

A preparation method of a pole piece comprises the following steps:

step one, preparing a conductive base film;

mixing a high molecular base material, an electronic conductor, diisocyanate and conductive carbon black, and preparing the mixture of the materials into a conductive base film by adopting film manufacturing equipment, wherein the equipment for manufacturing the film is a casting film machine;

plating metal layers on two opposite surfaces of the conductive base film by adopting magnetron sputtering equipment and a vacuum coating technology;

coating first active slurry on the surfaces of the two metal layers far away from the conductive base film, and drying for 12.5min at the temperature of 70 ℃ to form a first active material layer;

plating a lithium supplementing layer on the surfaces, far away from the metal layer, of the two first active material layers by adopting magnetron sputtering equipment and a vacuum coating technology;

and fifthly, coating second active slurry on the surfaces, far away from the first active material layer, of the two lithium supplement layers to form a second active material layer, and obtaining the pole piece.

Wherein the thickness of the conductive base film is 1.5 micrometers.

The conductive base film comprises the following components in parts by weight: 45 parts of polymer base material, 25 parts of electronic conductor, 7.5 parts of diisocyanate and 15 parts of conductive carbon black.

The polymer base material is PP particles, the electronic conductor is copper particles, and the particle size of the electronic conductor is 9.5 nm.

The metal layer is a copper layer, and the thickness of the metal layer is 1.5 microns.

The lithium supplement layer is a metal lithium layer, and the thickness of the lithium supplement layer is 250 nm.

Wherein the first active material layer has a higher conductivity than the second active material layer.

Wherein the first active material layer has a thickness of 1.5 microns; the thickness of the second active material layer was 42 μm.

Wherein the first active paste includes 15% of an active material, 25% of a conductive agent, and 55% of a binder. The second active paste includes 65% of an active material, 15% of a binder, and 15% of a conductive agent.

The conductive agent is acetylene black, the binder is styrene-butadiene latex, and the active material is lithium titanate.

Example 3

A preparation method of a pole piece comprises the following steps:

step one, preparing a conductive base film;

mixing a high molecular base material, an electronic conductor, diisocyanate and conductive carbon black, and preparing the mixture of the materials into a conductive base film by adopting film manufacturing equipment, wherein the equipment for manufacturing the film is a casting film machine;

plating metal layers on two opposite surfaces of the conductive base film by adopting a vacuum coating technology; specifically, the vacuum coating technology adopts magnetron sputtering equipment or vacuum evaporation equipment.

Coating first active slurry on the surfaces of the two metal layers far away from the conductive base film, and drying for 10min at the temperature of 60 ℃ to form a first active material layer;

plating a lithium supplementing layer on the surfaces of the two first active material layers far away from the metal layer by adopting a vacuum coating technology; specifically, the vacuum coating technology adopts magnetron sputtering equipment or vacuum evaporation equipment.

And fifthly, coating second active slurry on the surfaces, far away from the first active material layer, of the two lithium supplement layers to form a second active material layer, and obtaining the pole piece.

Wherein the thickness of the conductive base film is 1 micron.

The conductive base film comprises the following components in parts by weight: 40 parts of polymer base material, 20 parts of electronic conductor, 5 parts of diisocyanate and 10 parts of conductive carbon black.

Wherein the polymer base material is PP particles, PET particles or PE particles. The electronic conductor is copper particles. The particle diameter of the electronic conductor is 4 nm.

The metal layer is a copper layer, and the thickness of the metal layer is 1 micrometer.

The lithium supplement layer is a metal lithium layer, and the thickness of the lithium supplement layer is 10 nm.

Wherein the first active material layer has a higher conductivity than the second active material layer.

Wherein the first active material layer has a thickness of 1 micron; the thickness of the second active material layer was 10 μm.

Wherein the first active paste includes 10% of an active material, 20% of a conductive agent, and 50% of a binder. The second active paste includes 60% of an active material, 10% of a binder, and 10% of a conductive agent.

The conductive agent is Keqin black, the binder is polytetrafluoroethylene, and the active material is graphite.

Example 4

A preparation method of a pole piece comprises the following steps:

step one, preparing a conductive base film;

mixing a high molecular base material, an electronic conductor, diisocyanate and conductive carbon black, and preparing the mixture of the materials into a conductive base film by adopting film manufacturing equipment, wherein the equipment for manufacturing the film is a calender;

plating metal layers on two opposite surfaces of the conductive base film by using vacuum evaporation equipment and a vacuum coating technology;

coating first active slurry on the surfaces of the two metal layers far away from the conductive base film, and drying for 15min at the temperature of 80 ℃ to form a first active material layer;

plating a lithium supplementing layer on the surfaces, far away from the metal layer, of the two first active material layers by adopting vacuum evaporation equipment and a vacuum coating technology;

and fifthly, coating second active slurry on the surfaces, far away from the first active material layer, of the two lithium supplement layers to form a second active material layer, and obtaining the pole piece.

Wherein the thickness of the conductive base film is 2 micrometers.

The conductive base film comprises the following components in parts by weight: 50 parts of polymer base material, 30 parts of electronic conductor, 10 parts of diisocyanate and 20 parts of conductive carbon black.

Wherein, the polymer base material is PE particles. The electronic conductor is copper particles, and the particle size of the electronic conductor is 15 nm.

The metal layer is a copper layer, and the thickness of the metal layer is 2 microns.

Wherein, the lithium supplement layer is a metal lithium layer. The thickness of the lithium supplement layer is 300 nm.

Wherein the first active material layer has a higher conductivity than the second active material layer.

Wherein the first active material layer has a thickness of 2 microns; the thickness of the second active material layer was 70 μm.

Wherein the first active paste includes 20% of an active material, 30% of a conductive agent, and 60% of a binder. The second active paste includes 70% of an active material, 20% of a binder, and 20% of a conductive agent.

The conductive agent is conductive graphite, the binder is polyethylene oxide, and the active material is graphite.

Example 5

A method for preparing a pole piece, which is different from that of example 2 in that the electronic conductor in example 5 is aluminum particles. The metal layer is an aluminum layer, and the active material is lithium iron phosphate.

Preparation of the lithium ion batteries of the examples: the positive electrode plate is prepared by the preparation method of the embodiment 5, and correspondingly, the metal layer on the positive electrode plate is an aluminum layer, and the active material is lithium iron phosphate, so that the thickness of the positive electrode plate is kept at 50; the electrolyte consists of lithium salt LiBF4, solvent dimethyl carbonate and additive fluoroethylene carbonate, wherein the lithium salt LiBF4 is 1mol, and the ratio of the solvent dimethyl carbonate to the additive fluoroethylene carbonate is controlled to be 10: 1; then, in the glove box, button cells were assembled, and two groups of lithium ion batteries, namely experiment group 1 and experiment group 2, were prepared.

Preparation of comparative example: the positive pole piece of comparative example lithium ion battery adopts ordinary mass flow body, then coats active material lithium iron phosphate on this mass flow body to make the thickness of the anodal mass flow body keep the same with the thickness of the mass flow body of experiment group, for 50um, the negative pole piece is ordinary negative current collector, the metal on this mass flow body is copper, active material is graphite, make the thickness of whole negative current collector unanimous with the thickness of experiment group, for 50um, other are identical with the experiment group completely. And assembling to obtain the button cell, and dividing the lithium ion battery prepared in the comparative example into two groups, namely comparative example 1 and comparative example 2.

The HK-3560 precision battery internal resistance tester produced by Shenzhenjiao Jingzhida is used for testing the internal resistance of the lithium ion battery, and the experimental result is as follows:

internal resistance test	Comparative example 1	Comparative example 2	Experimental group 1	Experimental group 2
					Results	86.22mΩ	86.36mΩ	80.32mΩ	80.11mΩ

Therefore, the lithium ion battery adopting the pole piece has lower internal resistance.

While the preferred embodiments of the present invention have been illustrated and described, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.