Preparation device of negative electrode material

Abstract

The utility model provides a preparation device of a negative electrode material. The preparation device comprises a raw material pretreatment unit, a deposition coating unit, a vacuum unit and a control unit, the raw material pretreatment unit comprises a first preheating chamber, a second preheating chamber and a mixed heating chamber; an outlet of the first preheating chamber and an outlet of the second preheating chamber are respectively connected with an inlet of the mixed heating chamber; the deposition coating unit comprises a rotary furnace; an inlet of the rotary furnace is connected with an outlet of the mixed heating chamber; the vacuum unit comprises a vacuum assembly, and an inlet of the vacuum assembly is connected with an outlet of the rotary furnace. According to the preparation device, silicon deposition and carbon coating can be carried out on the negative electrode material, and the selection range of raw materials is wide; through pressure detection and valve control, the pressure of gas in the equipment is monitored in real time, and the treatment process is controlled, so that not only is the safety coefficient improved, but also the processes of silicon deposition and carbon coating can be performed in an intermittent manner, thereby improving the utilization rate of a raw material gas source; and the deposition and coating uniformity can also be improved.

Description

Technical Field

[0001] This utility model relates to an apparatus for preparing negative electrode materials. Background Technology

[0002] Silicon-carbon anode materials are important lithium-ion battery anode materials, with higher energy densities than graphite anode materials. There are two main production processes for silicon-carbon anode materials: rotary kiln vapor deposition coating and fluidized bed vapor deposition coating. However, the fluidized bed coating process suffers from problems such as high specific surface area of ​​the finished silicon-carbon product and uneven coating; therefore, rotary kilns are often used for silicon-carbon coating. To simplify the process flow and reduce time and cost issues, there is an urgent need to develop an integrated rotary kiln deposition and coating equipment to reduce the cost of the finished silicon-carbon product.

[0003] Rotary furnace deposition coating refers to the deposition of porous carbon materials with silane in a rotary furnace, followed by coating with a carbon source to form a silicon-carbon product. During the transition from deposition to coating, the equipment is cooled without stopping to ensure continuity between deposition and coating.

[0004] The gas required for industrial production of silicon-carbon anode materials is generally silane gas. Due to the flammability of silane, air must be absolutely isolated during the production process to ensure an oxygen-free environment. Fluidized bed vapor deposition coating technology is relatively mature and stable, but its production capacity cannot be scaled up. Although rotary kilns have a large capacity and can achieve dynamic sintering, insufficient material fluidization, uneven reaction, overheating of the inlet pipe along its length, premature decomposition of process gases, and blockage of the inlet are all drawbacks. These defects mean that rotary kiln vapor deposition coating technology is currently only at the experimental stage. Utility Model Content

[0005] To overcome the shortcomings of existing technologies for depositing or coating anode materials in rotary kilns, such as insufficient material fluidization, uneven reaction, excessive preheating of the inlet pipe along its length, premature decomposition of process gases, and blockage of the inlet, this invention provides a device for preparing anode materials. This device can perform both silicon deposition and carbon coating on anode materials, and offers a wide range of raw material options. Furthermore, by using pressure detection and valve control, the gas pressure within the equipment is monitored in real time, and the processing progress is controlled. This not only improves safety but also allows both silicon deposition and carbon coating processes to be performed intermittently, thereby increasing the utilization rate of the raw material gas source. This method also improves the uniformity of deposition and coating.

[0006] The present invention solves the above-mentioned technical problems through the following technical solution:

[0007] This invention provides an apparatus for preparing a negative electrode material, comprising a raw material pretreatment unit, a deposition and coating unit, a vacuum unit, and a control unit. The raw material pretreatment unit includes a first preheating chamber, a second preheating chamber, and a mixing heating chamber. The outlets of the first and second preheating chambers are respectively connected to the inlet of the mixing heating chamber. The first preheating chamber is used to preheat a first carrier gas or a silicon source material, and the second preheating chamber is used to preheat a carbon source material or a second carrier gas. The deposition and coating unit includes a rotary kiln. The inlet of the rotary kiln is connected to the outlet of the mixing heating chamber. The vacuum unit includes a vacuum assembly, the inlet of which is connected to the outlet of the rotary kiln.

[0008] The control unit includes a control center and a first valve, a second valve, a third valve, a first pressure detection element, a second pressure detection element, and a third pressure detection element, all electrically connected to the control center. The first pressure detection element and the first valve are both located in the connecting pipeline between the first preheating chamber and the mixing heating chamber. The second pressure detection element and the second valve are located in the connecting pipeline between the second preheating chamber and the mixing heating chamber. The third pressure detection element and the third valve are both located in the connecting pipeline between the vacuum assembly and the rotary kiln.

[0009] In this invention, the apparatus for preparing the negative electrode material can be used to perform silicon deposition and / or carbon coating on the negative electrode material, so that the silicon deposition process and the carbon coating process can be carried out in the same equipment.

[0010] In this invention, by setting up a first preheating chamber and a second preheating chamber, the range of raw material selection can be expanded; for example, when performing silicon deposition on the negative electrode material, gaseous, liquid and solid silicon source materials can be used.

[0011] In the process of silicon deposition on the negative electrode material, silicon source material and second carrier gas are introduced into the first preheating chamber and the second preheating chamber, respectively. The two materials are mixed and heated in the mixing heating chamber and then introduced into the rotary kiln to perform silicon deposition on the negative electrode material.

[0012] When carbon coating is applied to the negative electrode material, a first carrier gas and a carbon source material are introduced into the first preheating chamber and the second preheating chamber, respectively. The two materials are mixed and heated in the mixing heating chamber and then introduced into the rotary kiln to perform carbon coating treatment on the negative electrode material.

[0013] In this invention, when the feed material is a silicon source material or a carbon source material, the feed material to the first preheating chamber and the second preheating chamber can be a liquid or a solid.

[0014] In some embodiments, the rotary kiln includes a furnace tube and a drive mechanism for driving the furnace tube to rotate.

[0015] In a specific embodiment, the furnace tube is provided with a plurality of lifting plates and a material conveying device inside; the lifting plates are spirally distributed along the furnace tube and are located at the inlet end of the furnace tube; the material conveying device is located at the outlet end of the furnace tube.

[0016] The inlet end of the furnace tube is the end of the furnace tube closest to the mixing heating chamber; the outlet end of the furnace tube is the end of the furnace tube closest to the vacuum assembly.

[0017] In a specific embodiment, both ends of the furnace tube are provided with rotary joints, and each rotary joint is connected to the connecting pipe between the mixing heating chamber and the rotary furnace, and the connecting pipe between the rotary furnace and the vacuum assembly.

[0018] In a preferred embodiment, each rotary joint is provided with a filter element at its end to allow gas to pass through and trap solid materials.

[0019] In this invention, the vacuum component is connected to the rotary kiln, ensuring the overall airtightness of the preparation device. Furthermore, the furnace tubes in the rotary kiln are filled under negative pressure, which is beneficial for silicon deposition and carbon coating, and can also reduce the replacement time of the internal atmosphere of the preparation device.

[0020] In some embodiments, the vacuum assembly includes a vacuum pump, a dust collector, and a filter element for evacuating the interior of the apparatus for preparing the negative electrode material to a vacuum.

[0021] In some embodiments, the apparatus for preparing the negative electrode material further includes an exhaust gas emission unit; the exhaust gas emission unit is connected to the outlet of the vacuum assembly.

[0022] In a specific implementation, the exhaust gas emission unit includes an alkaline solution tank, a buffer tank, a liquid seal tank, and a flame arrester.

[0023] In some embodiments, the rotary kiln, the first preheating chamber, the second preheating chamber, and the mixing heating chamber are each independently equipped with a cooling and temperature control device to precisely control the temperature of the raw materials, thereby improving the equipment's production capacity and shortening the equipment's cooling time.

[0024] In some embodiments, the control unit further includes a fourth valve and a fourth pressure sensing element electrically connected to the control center, wherein the fourth valve and the fourth pressure sensing element are both located in the connecting pipeline between the mixing heating chamber and the rotary kiln; the first valve, the second valve, the third valve, and the fourth valve are all solenoid valves.

[0025] By using pressure sensing elements to adjust the solenoid valve, the gas supply and pressure can be precisely controlled, thereby improving the level of automation.

[0026] In this invention, a fifth valve may be provided at the entrance of the first preheating chamber, which is used to electrically or manually regulate the material entering the first preheating chamber when ventilation is required.

[0027] In this invention, a sixth valve may be provided at the entrance of the second preheating chamber, which is used to control the material entering the second preheating chamber electrically or manually when ventilation is required.

[0028] In this invention, when the vacuum pump pressurizes to -0.1 MPa, the first and second valves are opened to allow gas to flow into the rotary kiln. When the pressure detected by the third pressure detection element reaches a value of x, the first and second valves are closed to allow deposition or carbon coating to proceed; however, the vacuum pump of the vacuum assembly does not pump gas. The vacuum assembly is in a closed state during the gas source reaction stage.

[0029] The pressure detected by the first and second pressure detection elements reflects the remaining gas supply in the first and second preheating chambers, respectively. When the pressure is low, additional gas is supplied to prevent insufficient gas supply. The x-value is not fixed and can be set according to the process requirements.

[0030] In this invention, after the silicon deposition or carbon coating process is completed and the partial pressure drops to the maximum, evacuation is performed. At this time, the gas is inert, which improves the utilization rate of silicon or carbon. When there is no gas source in the furnace, the vacuum assembly is opened to extract the carrier gas, and then the vacuum assembly is closed, and the gas source and carrier gas are reintroduced.

[0031] Among them, the partial pressure represents the pressure detected by the third pressure detection element, and the complete point is also set according to the process and the filling ratio of silicon source gas and nitrogen gas, and does not represent a specific value.

[0032] In one embodiment, when the pressure detected by the third pressure detection element rises to 100 kPa, the gas supply is stopped. If the silicon source or acetylene accounts for 40 kPa, the complete point is set to 60 kPa, and the x value is 100 kPa.

[0033] The positive and progressive effects of this utility model are as follows:

[0034] 1. This application uses a pressure-detecting solenoid valve for control, which can monitor the gas pressure inside the furnace at all times, improve the safety factor, dynamically maintain equal pressure gas inside the furnace, and improve the uniformity of deposition coating and the utilization rate of gas source.

[0035] 2. The preparation device of this application has two front heating zones that can achieve independent temperature control, and has pressure detection and solenoid valve linkage control.

[0036] 3. The preparation device of this application adopts a two-stage heating and premixing method with gas source, which effectively improves the adsorption capacity of materials for gas and the uniformity of gas source entering the equipment. Attached Figure Description

[0037] Figure 1 This is the apparatus for preparing the negative electrode material in Embodiment 1 of this application.

[0038] Explanation of reference numerals in the attached figures:

[0039] First Preheating Chamber 1

[0040] Second preheating chamber 2

[0041] Hybrid heating chamber 3

[0042] Rotary furnace 4

[0043] Vacuum Component 5

[0044] First valve 6

[0045] First pressure sensing element 7

[0046] Second valve 8

[0047] Second pressure sensing element 9

[0048] Third valve 10

[0049] Third pressure sensing element 11

[0050] Fourth valve 12

[0051] Fourth pressure sensing element 13

[0052] Fifth valve 14

[0053] Sixth valve 15. Detailed Implementation

[0054] The present invention will be described more clearly and completely below with reference to the accompanying drawings, using a preferred embodiment.

[0055] Example 1

[0056] To achieve integrated deposition and coating of anode materials, this embodiment provides an apparatus for preparing anode materials, which includes a raw material pretreatment unit, a deposition and coating unit, a vacuum unit, a control unit, and an exhaust gas emission unit.

[0057] The raw material pretreatment unit includes a first preheating chamber 1, a second preheating chamber 2, and a mixing heating chamber 3. The outlets of the first preheating chamber 1 and the second preheating chamber 2 are connected to the inlet of the mixing heating chamber 3, respectively. The first preheating chamber 1 is used to preheat the first carrier gas or silicon source material, and the second preheating chamber 2 is used to preheat the carbon source material or the second carrier gas. The deposition and coating unit includes a rotary kiln 4. The inlet of the rotary kiln 4 is connected to the outlet of the mixing heating chamber 3. The vacuum unit includes a vacuum assembly 5, the inlet of which is connected to the outlet of the rotary kiln 4. The vacuum assembly 5 includes a vacuum pump, a dust collector, and a filter element. The exhaust gas emission unit is connected to the outlet of the vacuum assembly 5. The exhaust gas emission unit includes an alkali tank, a buffer tank, a liquid seal tank, and a flame arrester.

[0058] The control unit includes a control center and four valves electrically connected to the control center: a first valve 6, a second valve 8, a third valve 10, a first pressure sensing element 7, a second pressure sensing element 9, a third pressure sensing element 11, a fourth valve 12, and a fourth pressure sensing element 13. The first pressure sensing element 7 and the first valve 6 are both located in the connecting pipeline between the first preheating chamber 1 and the mixing heating chamber 3. The second pressure sensing element 9 and the second valve 8 are located in the connecting pipeline between the second preheating chamber 2 and the mixing heating chamber 3. The third pressure sensing element 11 and the third valve 10 are both located in the connecting pipeline between the vacuum assembly 5 and the rotary kiln 4. The fourth valve 12 and the fourth pressure sensing element 13 are both located in the connecting pipeline between the mixing heating chamber 3 and the rotary kiln 4. The first valve 6, the second valve 8, the third valve 10, and the fourth valve 12 are all solenoid valves.

[0059] The rotary kiln 4 includes a furnace tube and a drive mechanism, which drives the furnace tube to rotate. The furnace tube has several lifting plates and a material conveying device inside. The lifting plates are spirally distributed along the furnace tube and located at the inlet end. The material conveying device is located at the outlet end of the furnace tube. Rotary joints are located at both ends of the furnace tube, each connected to the connecting pipes of the mixing heating chamber 3 and the rotary kiln 4, and to the connecting pipes of the rotary kiln 4 and the vacuum assembly 5. Each rotary joint has a filter element at its end to allow gas to pass through while trapping solid materials. The rotary kiln 4, the first preheating chamber 1, the second preheating chamber 2, and the mixing heating chamber 3 each have their own independent cooling and temperature control devices.

[0060] Application Example 1

[0061] This application example describes the deposition and coating process of a negative electrode material, which uses the negative electrode material preparation apparatus of Example 1; it includes the following steps:

[0062] S1. Turn on vacuum component 5 to vacuum the preparation device to ensure that the adsorbed air in the pipeline is completely extracted by vacuum.

[0063] S2. Carrier gas is introduced into the rotary kiln 4 from the first preheating chamber 1 for replacement, and then the gas is extracted. When the oxygen content reaches the required level, deposition and coating are performed. In the rotary kiln 4, inert gas enters the first preheating chamber 1, and the gas source gas enters the second preheating chamber 2 and enters the mixed gas heating chamber with the preheated carrier gas. After thorough mixing, the mixture enters the rotary kiln 4 for reaction.

[0064] Specifically:

[0065] When the vacuum pump pressurizes to -0.1 MPa, the first valve 6 and the second valve 8 are opened to allow gas to flow into the rotary kiln 4. When the pressure detected by the third pressure sensing element 11 reaches the x value, the first valve 6 and the second valve 8 are closed to allow deposition or carbon coating to proceed; however, the vacuum pump of the vacuum assembly 5 does not pump gas. The vacuum assembly 5 is in a closed state during the gas source reaction stage.

[0066] After the silicon deposition or carbon coating process is completed and the partial pressure drops to the maximum, evacuation is performed. At this point, the gas is inert to improve the utilization rate of silicon or carbon. When there is no gas source in the furnace, vacuum assembly 5 is opened to extract the carrier gas. Then, vacuum assembly 5 is closed, and gas source and carrier gas are reintroduced.

[0067] Among them, the partial pressure represents the pressure detected by the third pressure detection element 11, and the complete point is also set according to the process and the filling ratio of silicon source gas and nitrogen gas, and does not represent a specific value.

[0068] The preparation apparatus of Example 1 can perform both silicon deposition and carbon coating on anode materials, and offers a wide range of raw material options. Furthermore, by using pressure detection and valve control, the gas pressure within the equipment is monitored in real time, and the processing progress is controlled, which not only improves the safety factor but also enhances the uniformity of deposition and coating. Moreover, both silicon deposition and carbon coating processes are performed intermittently, thereby improving the utilization rate of the raw material gas source. Compared to the conventional rotary kiln equipment in the art, which achieves a silicon source utilization rate of 91%, the preparation apparatus of Example 1 achieves a silicon source utilization rate of over 99.5% during intermittent deposition, an improvement of at least 8.5%, ensuring full utilization of the silicon source material.

Claims

1. An apparatus for preparing a negative electrode material, characterized in that, It includes a raw material pretreatment unit, a deposition and coating unit, a vacuum unit, and a control unit; The raw material pretreatment unit includes a first preheating chamber, a second preheating chamber, and a mixing heating chamber; the outlet of the first preheating chamber and the outlet of the second preheating chamber are respectively connected to the inlet of the mixing heating chamber; the first preheating chamber is used to preheat a first carrier gas or silicon source material, and the second preheating chamber is used to preheat a carbon source material or a second carrier gas. The deposition coating unit includes a rotary kiln; the inlet of the rotary kiln is connected to the outlet of the mixing heating chamber; The vacuum unit includes a vacuum assembly, the inlet of which is connected to the outlet of the rotary kiln; The control unit includes a control center and a first valve, a second valve, a third valve, a first pressure detection element, a second pressure detection element, and a third pressure detection element, all electrically connected to the control center. The first pressure detection element and the first valve are both located in the connecting pipeline between the first preheating chamber and the mixing heating chamber. The second pressure detection element and the second valve are located in the connecting pipeline between the second preheating chamber and the mixing heating chamber. The third pressure detection element and the third valve are both located in the connecting pipeline between the vacuum assembly and the rotary kiln.

2. The apparatus for preparing the negative electrode material as described in claim 1, characterized in that, The rotary kiln includes a furnace tube and a drive mechanism, the drive mechanism being used to drive the furnace tube to rotate.

3. The apparatus for preparing the negative electrode material as described in claim 2, characterized in that, The furnace tube is equipped with several lifting plates and material conveying devices inside; The lifting plates are spirally distributed along the furnace tube and are located at the inlet end of the furnace tube; The material conveying device is located at the outlet end of the furnace tube.

4. The apparatus for preparing the negative electrode material as described in claim 2, characterized in that, Both ends of the furnace tube are equipped with rotary joints, and each rotary joint is connected to the connecting pipe between the mixing heating chamber and the rotary furnace, and the connecting pipe between the rotary furnace and the vacuum assembly.

5. The apparatus for preparing the negative electrode material as described in claim 4, characterized in that, Each rotary joint is equipped with a filter element at its end to allow gas to pass through while trapping solid materials.

6. The apparatus for preparing the negative electrode material as described in claim 1, characterized in that, The vacuum assembly includes a vacuum pump, a dust collector, and a filter element.

7. The apparatus for preparing the negative electrode material as described in claim 1, characterized in that, The apparatus for preparing the negative electrode material also includes an exhaust gas emission unit; the exhaust gas emission unit is connected to the outlet of the vacuum component.

8. The apparatus for preparing the negative electrode material as described in claim 7, characterized in that, The exhaust gas emission unit includes an alkali tank, a buffer tank, a liquid seal tank, and a flame arrester.

9. The apparatus for preparing the negative electrode material as described in claim 1, characterized in that, The rotary kiln, the first preheating chamber, the second preheating chamber, and the mixing heating chamber are each equipped with an independent cooling and temperature control device.

10. The apparatus for preparing the negative electrode material as described in claim 1, characterized in that, The control unit also includes a fourth valve and a fourth pressure detection element that are electrically connected to the control center. The fourth valve and the fourth pressure detection element are both located in the connecting pipeline between the mixing heating chamber and the rotary kiln. The first valve, the second valve, the third valve, and the fourth valve are all solenoid valves.

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