Lithium manganese iron phosphate battery

Abstract

The invention relates to the technical field of batteries, in particular to a lithium manganese iron phosphate battery. The battery comprises the following components: a positive electrode material: lithium manganese iron phosphate; the negative electrode material is graphite or a silicon composite material; the electrolyte is an organic electrolyte containing LiPF6; the diaphragm is a polypropylene or polyethylene diaphragm; the battery shell is a metal shell or a composite shell; the positive electrode material is prepared by the following method: adding a nanoscale lithium source, a nanoscale manganese source, a nanoscale iron source and a nanoscale phosphorus source into a solvent according to the molar ratio of each element of lithium manganese iron phosphate, and dissolving to obtain a transparent solution A; adding a complexing agent into the transparent solution A, and mixing to obtain a mixed solution B; adding a graphdiyne solution into the mixed solution B, and mixing to obtain a mixed solution C; the lithium manganese iron phosphate positive electrode material is adopted, so that the battery has relatively high energy density and can meet the high-energy requirements in the fields of electric automobiles, mobile equipment and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of batteries, and in particular to a lithium manganese iron phosphate battery. Background Art

[0002] With the rapid development of electric vehicles, mobile devices and other fields, the demand for lithium-ion batteries with high energy density, long life and excellent safety performance is growing. Existing lithium-ion batteries mainly use positive electrode materials such as NCA (nickel cobalt aluminum) or NMC (nickel manganese cobalt). However, these materials are expensive and their safety performance needs to be improved under certain environments. Therefore, developing a new type of positive electrode material to increase the energy density of the battery while reducing costs and improving safety is an important direction of current technological development. Summary of the invention

[0003] The technical problem to be solved by the present invention is to overcome the deficiencies of the prior art and provide a lithium manganese iron phosphate battery and a preparation method thereof, which has high energy density, long life and excellent safety performance, and the preparation method is simple and low cost.

[0004] The technical solution of the present invention is:

[0005] A lithium manganese iron phosphate battery, characterized in that it comprises the following components:

[0006] Cathode material: lithium iron manganese phosphate;

[0007] Anode material: graphite or silicon composite material;

[0008] Electrolyte: Contains LiPF 6 of organic electrolyte;

[0009] Diaphragm: polypropylene or polyethylene diaphragm;

[0010] Battery shell: metal shell or composite shell.

[0011] Preferably, the positive electrode material is prepared by the following method:

[0012] According to the molar ratio of each element of lithium manganese iron phosphate, a nanometer-scale lithium source, a manganese source, an iron source, and a phosphorus source are added into a solvent for dissolution treatment to obtain a transparent solution A;

[0013] Adding a complexing agent to the transparent solution A and mixing the mixture to obtain a mixed solution B;

[0014] Adding a gyrene solution to the mixed solution B and mixing them to obtain a mixed solution C; wherein the amount of the gyrene solution added ensures that the gyrene is 0.5-5% of the mass of the theoretically generated lithium iron manganese phosphate; the mass concentration of the gyrene solution is 20%-80%, and the dripping rate of the gyrene solution added to the mixed solution B is 1d / min-10d / min;

[0015] The mixed solution C is dried to obtain a lithium manganese iron phosphate composite positive electrode material precursor;

[0016] The lithium manganese iron phosphate composite positive electrode material precursor is ground, sieved through 50-300 mesh, heat treated at 500-900°C in a protective atmosphere, and then annealed; wherein the annealing treatment is performed in a protective atmosphere at a rate of 1-5°C / min to cool to room temperature.

[0017] Preferably, the negative electrode material is prepared by the following method: mixing natural graphite or silicon composite material with an organic binder to obtain the negative electrode material.

[0018] Preferably, the electrolyte is prepared by the following method: dissolving LiPF6 in an organic solvent to obtain an electrolyte.

[0019] Preferably, the diaphragm is prepared by the following method: melt-extruding, stretching and heat-treating polypropylene or polyethylene resin to obtain the diaphragm.

[0020] Preferably, the battery assembly process is performed in a dry, dust-free environment.

[0021] Preferably, after the battery is subjected to charge and discharge test and cycle life test, its performance indicators meet the following requirements: the energy density of the battery is greater than 150Wh / kg, and the cycle life is greater than 2000 times.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] High energy density: Due to the use of lithium iron manganese phosphate (LMP) positive electrode material, the battery has a high energy density and can meet the high energy requirements of electric vehicles, mobile devices and other fields.

[0024] Long life: Due to the high chemical stability and structural stability of LMP positive electrode materials, the battery has a long cycle life and can meet the needs of long-term use.

[0025] Excellent safety performance: Due to the use of graphite or silicon composite materials as negative electrode materials, the battery has good safety performance and can ensure the safety of the battery under abnormal circumstances.

[0026] Simple and easy preparation method: The preparation method of the present invention is simple and easy, the ratio between the components is highly accurate, and large-scale production of batteries can be achieved at a relatively low cost.

[0027] Applicable to various environments: Since the battery of the present invention has good adaptability, it can work normally in various environments, such as high temperature, low temperature, humidity and the like. DETAILED DESCRIPTION

[0028] In order to enable those skilled in the art to better understand the technical solutions in the present invention, the technical solutions in the embodiments of the present invention are described clearly and completely. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0029] Example

[0030] A lithium manganese iron phosphate battery, characterized in that it comprises the following components:

[0031] Cathode material: lithium iron manganese phosphate;

[0032] Anode material: graphite or silicon composite material;

[0033] Electrolyte: Contains LiPF 6 of organic electrolyte;

[0034] Diaphragm: polypropylene or polyethylene diaphragm;

[0035] Battery shell: metal shell or composite shell.

[0036] Preferably, the positive electrode material is prepared by the following method:

[0037] According to the molar ratio of each element of lithium manganese iron phosphate, a nanometer-scale lithium source, a manganese source, an iron source, and a phosphorus source are added into a solvent for dissolution treatment to obtain a transparent solution A;

[0038] Adding a complexing agent to the transparent solution A and mixing the mixture to obtain a mixed solution B;

[0039] Adding a gyrene solution to the mixed solution B and mixing them to obtain a mixed solution C; wherein the amount of the gyrene solution added ensures that the gyrene is 0.5-5% of the mass of the theoretically generated lithium iron manganese phosphate; the mass concentration of the gyrene solution is 20%-80%, and the dripping rate of the gyrene solution added to the mixed solution B is 1d / min-10d / min;

[0040] The mixed solution C is dried to obtain a lithium manganese iron phosphate composite positive electrode material precursor;

[0041] The lithium manganese iron phosphate composite positive electrode material precursor is ground, sieved through 50-300 mesh, heat treated at 500-900°C in a protective atmosphere, and then annealed; wherein the annealing treatment is performed in a protective atmosphere at a rate of 1-5°C / min to cool to room temperature.

[0042] Preferably, the negative electrode material is prepared by the following method: mixing natural graphite or silicon composite material with an organic binder to obtain the negative electrode material.

[0043] Preferably, the electrolyte is prepared by the following method: dissolving LiPF6 in an organic solvent to obtain an electrolyte.

[0044] Preferably, the diaphragm is prepared by the following method: melt-extruding, stretching and heat-treating polypropylene or polyethylene resin to obtain the diaphragm.

[0045] Preferably, the battery assembly process is performed in a dry, dust-free environment.

[0046] Preferably, after the battery is subjected to charge and discharge test and cycle life test, its performance indicators meet the following requirements: the energy density of the battery is greater than 150Wh / kg, and the cycle life is greater than 2000 times.

[0047] Although the present invention has been described in detail by way of preferred embodiments, the present invention is not limited thereto. Without departing from the spirit and essence of the present invention, a person of ordinary skill in the art may make various equivalent modifications or substitutions to the embodiments of the present invention, and these modifications or substitutions shall be within the scope of the present invention. Any person of ordinary skill in the art may easily think of changes or substitutions within the technical scope disclosed by the present invention, and these shall be within the scope of protection of the present invention. Therefore, the scope of protection of the present invention shall be subject to the scope of protection of the claims.

Claims

1. A lithium manganese iron phosphate battery, It is characterized in that Includes the following components: Cathode material: lithium iron manganese phosphate; Anode material: graphite or silicon composite material; Electrolyte: Contains LiPF 6 of organic electrolyte; Diaphragm: polypropylene or polyethylene diaphragm; Battery shell: metal shell or composite shell.

2. According to the lithium manganese iron phosphate battery of claim 1, the positive electrode material is prepared by the following method: According to the molar ratio of each element of lithium manganese iron phosphate, a nanometer-scale lithium source, a manganese source, an iron source, and a phosphorus source are added into a solvent for dissolution treatment to obtain a transparent solution A; Adding a complexing agent to the transparent solution A and mixing the mixture to obtain a mixed solution B; Adding a gyrene solution to the mixed solution B and mixing them to obtain a mixed solution C; wherein the amount of the gyrene solution added ensures that the gyrene is 0.5-5% of the mass of the theoretically generated lithium iron manganese phosphate; the mass concentration of the gyrene solution is 20%-80%, and the dripping rate of the gyrene solution added to the mixed solution B is 1d / min-10d / min; The mixed solution C is dried to obtain a lithium manganese iron phosphate composite positive electrode material precursor; The lithium manganese iron phosphate composite positive electrode material precursor is ground, sieved through 50-300 mesh, heat treated at 500-900°C in a protective atmosphere, and then annealed; wherein the annealing treatment is performed in a protective atmosphere at a rate of 1-5°C / min to cool to room temperature.

3. According to the lithium manganese iron phosphate battery of claim 1 or 2, the negative electrode material is prepared by the following method: mixing natural graphite or silicon composite material with an organic binder to obtain the negative electrode material.

4. According to the lithium manganese iron phosphate battery of claim 3, the electrolyte is prepared by the following method: dissolving LiPF6 in an organic solvent to obtain an electrolyte.

5. According to the lithium manganese iron phosphate battery of claim 4, the diaphragm is prepared by the following method: melt-extruding, stretching and heat-treating polypropylene or polyethylene resin to obtain the diaphragm.

6. According to the lithium manganese iron phosphate battery of claim 5, the battery assembly process is carried out in a dry and dust-free environment.

7. According to claim 5 or 6, a lithium manganese iron phosphate battery, after the battery is subjected to charge and discharge test and cycle life test, its performance indicators meet the following requirements: the energy density of the battery is greater than 150Wh / kg, and the cycle life is greater than 2000 times.