CN206541886U - Electrode pole piece for lithium ion battery - Google Patents

Abstract

The utility model relates to an electrode plate for lithium ion battery belongs to the lithium ion battery field. The electrode pole piece for the lithium ion battery consists of a pole piece body and a pole lug, wherein the main body of the pole piece body is a current collector framework, the current collector framework is provided with a three-dimensional network structure, and a grid formed by the three-dimensional network structure is an irregular grid; a carbon layer is covered on the surface of the current collector framework grid; the interior of the grid is completely filled with a filler, and the filler is a mixture formed by dispersing titanium dioxide/niobium titanium oxide particles in polymer pyrolytic carbon. The utility model provides an electrode plate for lithium ion battery does not introduce common conductive agent and binder in traditional lithium ion battery pole piece, but constructs into the pole piece that has good dispersibility and high adhesion nature through the adhesive action of the polymer pyrolytic carbon between the three-dimensional network skeleton texture mass flow body of active composite electrode material and hole coating carbon layer to have advantages such as low cost, easy shaping.

Description

Electrode pole piece for lithium ion battery

technical field

The utility model relates to an electrode pole piece for a lithium-ion battery, in particular to a titanium dioxide/niobium-titanium oxide composite electrode pole piece which can be used as a negative pole of a lithium-ion battery and has high charge-discharge reversibility and good cycle performance. ion battery field.

Background technique

With the miniaturization of various portable electronic devices and the widespread demand for electric vehicles, the demand and performance requirements for chemical power sources have increased sharply, while traditional lithium-ion batteries use carbon materials as their negative electrode materials. Due to the limitation of the diffusion rate in the crystal lattice, when the carbon-based negative electrode material is overcharged and charged with a large current, it is easy to cause the deposition of lithium dendrites on its surface, and the lithium dendrites are easy to pierce the separator material separating the positive and negative electrodes, thereby causing Potential safety hazards such as battery micro-short circuit or local overheating. This is also one of the bottlenecks in the application of lithium-ion batteries in the field of power batteries. Therefore, finding safer new electrode materials is an important topic in the research of lithium-ion batteries.

The new generation of nano-scale lithium-ion battery oxide anode materials developed with _TiO2 as the matrix has excellent electrochemical reversibility due to its high lithium-intercalation potential and can effectively inhibit the decomposition of the electrolyte on the surface of the electrode material. . In addition, the biggest feature of this type of material is that since the electrochemical power storage reaction occurs at a higher potential, the precipitation of lithium can be avoided to the greatest extent. Therefore, this type of material can not only reduce the damage caused by irreversible electrolyte decomposition Lithium source consumption problem, and can avoid the precipitation of lithium dendrites on the surface of the electrode, thereby avoiding the micro-short circuit of the battery caused by the puncture of the diaphragm, and effectively improving the safety of the lithium-ion battery.

However, when this type of zero-volume effect oxide material is used as the negative electrode material of lithium-ion batteries, due to its semiconductor characteristics, its electronic and lithium-ion conductivity is low, so it is necessary to reduce the size of the material to increase the contact area between the material and the conductive agent. Meet the high current charge and discharge conditions. Therefore, for the preparation of such oxide material composite negative electrodes, most of the materials are highly dispersed in the conductive agent, and the mass and volume percentage of the conductive agent in the electrode are increased to overcome the low conductivity of the material itself. However, adding more conductive agents to the negative electrode material improves its conductivity on the one hand, and reduces the volume effect in the electrochemical process to a certain extent, but on the other hand, it also reduces the volume density of the electrode.

Contents of the invention

The purpose of the utility model is to provide an electrode pole piece for a lithium ion battery, aiming at the low conductivity of titanium dioxide/niobium titanium oxide, to provide a new type of negative composite pole piece with a three-dimensional network structure. The pole piece is composed of a titanium dioxide/niobium titanium oxide composite negative electrode material, a three-dimensional metal current collector skeleton coated with a carbon layer on the surface of the inner hole, and a pole lug. This new structure does not introduce conductive agents and binders, and the pole piece is formed by the adhesion between the titanium dioxide/niobium titanium oxide composite negative electrode material, polymer pyrolytic carbon and the three-dimensional skeleton current collector coated with carbon layer, The basic configuration formed by the three-dimensional metal network and the carbon layer on the surface of the current collector grid and the pyrolytic carbon between the negative electrode particles improve the electrical contact performance of the electrode active material and improve its cycle stability.

An electrode pole piece for a lithium ion battery, the electrode pole piece is composed of a pole piece body and a tab,

The main body of the pole piece body is a current collector skeleton, and the current collector skeleton has a three-dimensional network structure, and the grid formed by the three-dimensional network structure is an irregular grid; the surface of the current collector skeleton grid is covered with a carbon layer ; The interior of the grid is completely filled with a filler, which is a mixture formed by dispersing titanium dioxide/niobium titanium oxide particles in polymer pyrolytic carbon.

The main body of the lithium-ion electrode pole piece provided by the utility model is a current collector framework, and the current collector framework adopts a three-dimensional network structure instead of the two-dimensional flat metal film commonly used in traditional lithium-ion batteries. The current collector not only plays the role of current collection, but also It also serves as the basic frame of the electrode to form the supporting structure of the electrode. The grid formed by the three-dimensional network structure of the current collector skeleton is an irregular hole. The inner surface of the current collector skeleton with three-dimensional irregular holes is covered with a highly conductive carbon layer; the titanium dioxide/niobium titanium oxide composite negative electrode material is dispersed in polymer pyrolytic carbon and fixed on the current collector skeleton by pyrolytic carbon. In the network structure of the electrode, the lithium intercalation and removal process is completed by the electron transport of the current collector, which is the active center of the electrode; the tab is connected with the metal current collector by spot welding, and connected with the external circuit to form a current path. This three-dimensional filling structure is beneficial to improve the binding force between the current collector and the titanium dioxide/niobium-titanium oxide composite negative electrode material, and effectively bind the electrode material in the three-dimensional irregular cavity structure. The carbon layer on the surface of the inner pores of the three-dimensional metal current collector further improves the electrical conductivity and improves the cycle stability of the overall electrode.

The electrode pole piece for lithium-ion batteries described in the utility model is preferably fixed in the irregular three-dimensional grid of the current collector skeleton through the bonding effect of the polymer pyrolytic carbon generated by polymer pyrolysis of the titanium dioxide/niobium titanium oxide particles. .

The electrode pole piece for the lithium ion battery of the present invention preferably has a thickness of the carbon layer of 1-10 microns.

Preferably, the material of the carbon layer is one of graphite carbon, graphene, activated carbon, amorphous carbon or a mixture thereof for the lithium-ion battery electrode pole piece of the present invention.

Preferably, the carbon layer of the lithium-ion battery electrode sheet in the present invention is covered on the grid surface of the current collector by immersing the current collector skeleton in a solution containing carbon material and then drying it.

The lithium-ion battery electrode pole piece of the utility model is preferably composed of titanium oxide/niobium-titanium oxide particles and polymer high-temperature pyrolytic carbon, and the titanium dioxide/niobium-titanium oxide particles are spherical niobium-titanium oxide particles. Anatase-type titanium dioxide particles are dispersed on the surface of the oxide, and the amorphous niobium-titanium oxide is a compound with the general formula Ti _x Nb _y O _2x+2.5y , x=0.1-1, y=1-2; A polymer is any polymer that can be pyrolyzed to carbon at high temperature.

Further, preferably, the polymer is polypropylene, polyvinyl chloride.

The electrode pole piece for the lithium ion battery described in the utility model preferably has the current collector skeleton as an electrode active material that can be evenly dispersed on the neutralization surface, and has a certain high temperature resistance and good electrical conductivity. It is preferably foam nickel or foam copper.

The beneficial effects of the utility model are: the electrode pole piece for lithium ion battery provided by the utility model does not introduce the conductive agent and binder commonly used in the traditional lithium ion battery pole piece, but is coated with the active composite electrode material and the inner hole. The bonding effect of polymer pyrolytic carbon between the current collectors of the carbon-coated three-dimensional network skeleton structure forms a pole piece with good dispersion and high adhesion, which is the structure of the utility model that is different from other types of pole pieces salient features. And it has the advantages of low cost and easy molding.

Description of drawings

Fig. 1 is a kind of schematic diagram of microstructure of electrode pole piece for lithium ion battery;

Fig. 2 is a schematic diagram of the basic structure of an electrode pole piece for a lithium-ion battery, and the reference signs are as follows:

1. Current collector skeleton, 2. Carbon layer, 3. Titanium dioxide/niobium titanium oxide particles, 4. Polymer pyrolytic carbon, 5. Ears.

detailed description

The following non-limiting examples can enable those skilled in the art to understand the present invention more fully, but do not limit the present invention in any way.

The test methods described in the following examples, unless otherwise specified, are conventional methods; the reagents and materials, unless otherwise specified, can be obtained from commercial sources.

Example 1

An electrode pole piece for a lithium ion battery, the electrode pole piece is composed of a pole piece body and a tab 5, and the tab 5 is welded to one end of the outer edge of the pole piece body.

The body body of the pole piece is a current collector skeleton 1, and the current collector skeleton 1 has a three-dimensional network structure, and the grid formed by the three-dimensional network structure is an irregular grid; the grid surface of the current collector skeleton 1 is covered There is a carbon layer 2; the inside of the grid is completely filled with a filler, which is a mixture formed by dispersing titanium dioxide/niobium titanium oxide particles 3 in polymer pyrolytic carbon 4 .

The titanium dioxide/niobium titanium oxide particles are fixed in the irregular three-dimensional grid of the current collector skeleton 1 through the bonding effect of the polymer pyrolytic carbon 4 generated by polymer pyrolysis. The carbon layer 2 has a thickness of 8 microns. The carbon material of the carbon layer 2 is a graphitic carbon layer. The carbon layer 2 is covered on the grid surface of the current collector by immersing the current collector skeleton 1 in a solution containing graphite carbon powder and drying.

The filler is composed of titanium oxide/niobium titanium oxide particles and polymer high-temperature pyrolytic carbon. The titanium dioxide/niobium titanium oxide particles are spherical niobium titanium oxide particles with anatase titanium dioxide particles dispersed on the surface. The amorphous niobium titanium oxide is a compound with the general formula Ti _x Nb _y O _2x+2.5y , x=0.5, y=2; the polymer is polypropylene; the current collector skeleton 1 is nickel foam.

Example 2

An electrode pole piece for a lithium ion battery, the electrode pole piece is composed of a pole piece body and a tab 5, and the tab 5 is welded to one end of the outer edge of the pole piece body.

The body body of the pole piece is a current collector skeleton 1, and the current collector skeleton 1 has a three-dimensional network structure, and the grid formed by the three-dimensional network structure is an irregular grid; the grid surface of the current collector skeleton 1 is covered There is a carbon layer 2; the inside of the grid is completely filled with a filler, which is a mixture formed by dispersing titanium dioxide/niobium titanium oxide particles 3 in polymer pyrolytic carbon 4 .

The titanium dioxide/niobium titanium oxide particles are fixed in the irregular three-dimensional grid of the current collector skeleton 1 through the bonding effect of the polymer pyrolytic carbon 4 generated by polymer pyrolysis. The carbon layer 2 has a thickness of 3 microns. The carbon material of the carbon layer 2 is a mixture of graphene and amorphous carbon. The carbon layer 2 is covered on the surface of the current collector grid by immersing the current collector skeleton 1 in a solution containing a mixture of graphene and amorphous carbon and then drying.

The filler is composed of titanium oxide/niobium titanium oxide particles and polymer high-temperature pyrolytic carbon. The titanium dioxide/niobium titanium oxide particles are spherical niobium titanium oxide particles with anatase titanium dioxide particles dispersed on the surface. The amorphous niobium titanium oxide is a compound with the general formula Ti _x Nb _y O _2x+2.5y , x=0.2, y=1.3; the polymer is polyvinyl chloride; the current collector skeleton 1 is copper foam.

Claims (5)

1. a kind of lithium ion battery electrode plates, it is characterised in that：The electrode plates are by pole piece body and lug (5) group Into,

The pole piece body party is collector skeleton (1), and the collector skeleton (1) has three-dimensional net structure, with three The internal surface of hole for tieing up the collector skeleton of irregular holes is covered with the carbon-coating of high conductivity；Titanium dioxide/niobium-titanium oxide is combined Negative material is scattered in Polymer-pyrolysis carbon and is fixed on by pyrolytic carbon in the network structure of collector skeleton formation.

2. electrode plates according to claim 1, it is characterised in that：The thickness of the carbon-coating (2) is 1~10 micron.

3. electrode plates according to claim 1, it is characterised in that：The carbon material of the carbon-coating (2) is graphitic carbon, graphite Alkene, activated carbon, one kind of agraphitic carbon.

4. electrode plates according to claim 1, it is characterised in that：The polymer is polypropylene or polyvinyl chloride.

5. electrode plates according to claim 1, it is characterised in that：The collector skeleton (1) is nickel foam or foam Copper.