Double-furnace and multi-furnace synchronous purification process for producing negative electrode material of lithium battery

Abstract

The invention discloses a double-furnace and multi-furnace synchronous purification process for producing a lithium battery negative electrode material, which is characterized in that the later stage of power transmission purification is a material constant temperature stage, at the moment, the power transmission power of a transformer is greatly reduced and power is supplied at intervals, and at the moment, power can be supplied to a second furnace body according to a power transmission purification curve; and so on, after the N furnace bodies enter the material constant temperature stage, the transformer supplies power to the (N + 1) th furnace body according to the power supply purification curve, and power supply to the next furnace body does not need to be performed until the power supply period is completely finished. According to the process, the original average power transmission period of each furnace is shortened from 5-6 days to less than 4 days, the production period is greatly shortened, one transformer can transmit one furnace of power at a time, after the process is reformed, under the same conditions, one transformer can transmit 2-3 furnaces of power at the same time before and in the middle stage of graphitization, the production efficiency is improved, the capacity of the transformer is fully utilized, and the production cost is reduced. And the production cost of graphitization enterprises is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of production of negative electrode materials for lithium batteries, and in particular to a dual-furnace or multi-furnace synchronous purification process for production of negative electrode materials for lithium batteries. Background Art

[0002] The production of lithium batteries cannot be separated from artificial graphite. Graphitization is a key process in the production of artificial graphite. It mainly uses thermal activation to transform thermodynamically unstable carbon atoms from a chaotic layer structure to a graphite crystal structure in an orderly manner. At present, our company adopts the graphitization Acheson box furnace production process. The box is built with refractory bricks, graphite electrode strips, and graphite blocks. Semi-graphite materials are used to make box plates of varying specifications (including bottom plates, side plates, upper covers, and baffles). Carbon black is laid under the bottom plate, and carbon black powder is filled between the side plates and the outer furnace body. In the existing process, each production line has 12 furnaces, equipped with a transformer of the corresponding model for power supply, and each power supply cycle during the production process can only supply power to one of the graphitization furnaces. This process has low production efficiency, wastes transformer capacity costs, and increases the production cost of graphitization enterprises. Summary of the invention

[0003] The technical problem to be solved by the present invention is to overcome the existing defects and provide a dual-furnace, multi-furnace synchronous purification process for the production of lithium battery negative electrode materials, which can effectively solve the problems in the background technology.

[0004] To achieve the above object, the present invention provides the following technical solution: a dual-furnace, multi-furnace synchronous purification process for the production of lithium battery negative electrode materials, comprising the following steps:

[0005] Step 1: Check incoming materials and load 12 furnaces in a production line;

[0006] Step 2: Formulate the power transmission and purification curve for each furnace;

[0007] Step 3, supplying power to the first furnace in the production line according to the power supply and purification curve;

[0008] Step 4: The later stage of power transmission and purification is the material constant temperature stage. At this time, the power transmission of the transformer is greatly reduced and the power supply is intermittent. At this time, the second furnace can be powered according to the power transmission and purification curve;

[0009] Step 5: Similarly, after N furnace bodies enter the material constant temperature stage, the transformer supplies power to the N+1th furnace body according to the power supply purification curve, without waiting until the power supply cycle is completely completed before supplying power to the next furnace body;

[0010] Step six: After the power supply cycle, each furnace body enters the cooling, furnace unloading and finished product inspection process.

[0011] As a preferred technical solution of the present invention, the power transmission purification curve in step 2 is formulated according to the graphitization degree, capacity, specific surface area, pH value and fiber index of the material.

[0012] As a preferred technical solution of the present invention, in step three, during the drainage, volatile matter, sulfur, magnetic substance and molecular qualitative change conversion stages of the negative electrode material in the graphitization power supply process, different amounts of electricity are respectively fed into the graphitization furnace to reach the optimal reaction temperature.

[0013] As a preferred technical solution of the present invention, the optimal reaction temperature for removing water in step three is 100°C, the optimal reaction temperature for removing volatile matter is 400-1200°C, the optimal reaction temperature for removing sulfur is 1800-2500°C, the optimal reaction temperature for removing magnetically attracted substances is 2200-3000°C, and the optimal reaction temperature for the molecular qualitative change of the negative electrode material is not less than 3000°C.

[0014] As a preferred technical solution of the present invention, in step five, since the duration of the material constant temperature stage is much longer than the duration of the power supply and temperature rise stage, one transformer can supply power to 2 to 3 furnace bodies at the same time.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] (1) The average power supply cycle of each furnace was shortened from 5 to 6 days to less than 4 days, which greatly shortened the production cycle. The original transformer could only supply power to one furnace at a time. After the process reform, under the same conditions, in the early and middle stages of graphitization, one transformer can supply power to 2 to 3 furnaces at the same time.

[0017] (2) The simultaneous purification of two or more furnaces reduces the power consumption per ton of negative electrode material by 200 to 300 KWH.

[0018] (3) The dual-furnace or multi-furnace synchronous purification method solves the problem of staggered power transmission during peak and valley periods without affecting production progress.

[0019] (4) This process improves production efficiency, fully utilizes transformer capacity, and reduces the production cost of graphitization enterprises. DETAILED DESCRIPTION

[0020] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0021] The present invention provides a technical solution: a dual-furnace, multi-furnace synchronous purification process for the production of lithium battery negative electrode materials, comprising the following steps:

[0022] Step 1: Check incoming materials and load 12 furnaces in a production line;

[0023] Step 2: Formulate a power transmission and purification curve for each furnace body; the power transmission and purification curve is formulated according to the graphitization degree, capacity, specific surface area, pH value, and fiber index of the material;

[0024] Step three, supply power to the first furnace body in the production line according to the power supply and purification curve; in the stages of water discharge, volatile discharge, sulfur discharge, magnetic substance discharge, and molecular mass change conversion of negative electrode materials in the graphitization power supply process, different amounts of electricity are respectively supplied to the graphitization furnace to make it reach the optimal reaction temperature; the optimal reaction temperature of water discharge is 100°C, the optimal reaction temperature of volatile discharge is 400-1200°C, the optimal reaction temperature of sulfur discharge is 1800-2500°C, the optimal reaction temperature of magnetic attraction discharge is 2200-3000°C, and the optimal reaction temperature of molecular mass change conversion of negative electrode materials is not less than 3000°C.

[0025] Step 4: The later stage of power transmission and purification is the material constant temperature stage. At this time, the power transmission of the transformer is greatly reduced and the power supply is intermittent. At this time, the second furnace can be powered according to the power transmission and purification curve;

[0026] Step 5: Similarly, after N furnace bodies enter the material constant temperature stage, the transformer supplies power to the N+1th furnace body according to the power supply purification curve, without waiting for the power supply cycle to end completely before supplying power to the next furnace body. Since the material constant temperature stage is much longer than the power supply temperature rise stage, one transformer can supply power to 2 to 3 furnace bodies at the same time, shortening the average power supply cycle of each furnace and improving production efficiency.

[0027] Step 6: After the power supply cycle, each furnace enters the cooling, unloading and finished product inspection process. The following table is the power supply table of one of the furnaces recorded by our company:

[0028]

[0029]

[0030] Purification power meter

[0031] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A dual-furnace or multi-furnace synchronous purification process for the production of negative electrode materials for lithium batteries, characterized in that: The following steps are involved: Step 1: Check incoming materials and load 12 furnaces in a production line; Step 2: Formulate the power transmission and purification curve for each furnace body; Step 3, supplying power to the first furnace in the production line according to the power supply and purification curve; Step 4: The later stage of power transmission and purification is the material constant temperature stage. At this time, the power transmission of the transformer is greatly reduced and the power supply is intermittent. At this time, the second furnace can be powered according to the power transmission and purification curve; Step 5, and so on, after N furnace bodies enter the material constant temperature stage, the transformer supplies power to the N+1th furnace body according to the power supply purification curve, without waiting until the power supply cycle is completely over before supplying power to the next furnace body. Step six: After the power supply cycle, each furnace body enters the cooling, furnace unloading and finished product inspection process.

2. The dual-furnace and multi-furnace synchronous purification process for the production of lithium battery negative electrode materials according to claim 1, characterized in that: The power transmission purification curve in step 2 is formulated according to the graphitization degree, capacity, specific surface area, pH value and fiber index of the material.

3. The dual-furnace and multi-furnace synchronous purification process for the production of lithium battery negative electrode materials according to claim 1, characterized in that: In step three, during the drainage, volatile matter, sulfur, magnetic substance and molecular mass transformation stages of the negative electrode material in the graphitization power supply process, different amounts of electricity are respectively fed into the graphitization furnace to reach the optimal reaction temperature.

4. The dual-furnace and multi-furnace synchronous purification process for the production of lithium battery negative electrode materials according to claim 3, characterized in that: In step three, the optimal reaction temperature for removing water components is 100°C, the optimal reaction temperature for removing volatile components is 400-1200°C, the optimal reaction temperature for removing sulfur is 1800-2500°C, the optimal reaction temperature for removing magnetically attracted substances is 2200-3000°C, and the optimal reaction temperature for the molecular qualitative change of the negative electrode material is not less than 3000°C.

5. The dual-furnace and multi-furnace synchronous purification process for the production of lithium battery negative electrode materials according to claim 1, characterized in that: In step five, since the material constant temperature stage duration is much longer than the power supply and temperature rise stage duration, one transformer can supply power to 2 to 3 furnaces at the same time.

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