METHOD AND APPARATUS FOR PREPARING A Ternary CATHODE MATERIAL

Abstract

The invention relates to a method for producing a ternary cathode material (130) for a lithium battery by roasting a raw material (110) in a roasting furnace (120), in which an atmosphere is provided in the roasting furnace (120), in which the injection of a gas component (a) of the atmosphere into the roasting furnace (120) is controlled in a closed-loop control manner on the basis of at least one measured process influencing parameter, an apparatus for preparing the ternary cathode material (130) is also disclosed.

Description

[0001] This application is a divisional application of the invention application with application number 201980091493.5, application date February 26, 2019, entitled "Method and apparatus for preparing ternary cathode materials". Technical Field

[0002] This invention relates to a method and apparatus for preparing ternary cathode materials for lithium batteries by calcining raw materials in a calcining furnace. Background Technology

[0003] The market for electric and hybrid vehicles is growing rapidly. This has created a growing demand for lithium-ion batteries, commonly used in the automotive industry. Lithium-ion batteries consist of cathode and anode materials, as well as other components. The processes for preparing these materials and components typically use gases such as oxygen, nitrogen, and argon.

[0004] Driven by the demand for long-range electric vehicles and hybrid vehicles, the lithium-ion battery industry needs to seek cathode materials with higher energy density and corresponding solutions. So-called ternary cathode materials with higher energy density have become a trend in the industry. These ternary cathode materials for lithium-ion batteries are typically prepared by calcining raw materials in a calcination furnace, which provides the necessary atmosphere.

[0005] The present invention aims to increase the likelihood of obtaining products from raw materials roasted in a roasting furnace, and thus provide better lithium batteries. Summary of the Invention

[0006] This objective is achieved by providing the method and apparatus according to the independent claims.

[0007] A method according to the invention is used to prepare ternary cathode materials for lithium batteries (or lithium-ion batteries) by calcining raw materials in a calcining furnace, wherein an atmosphere is provided in the calcining furnace. A continuous roller hearth furnace or pusher furnace is preferably used as the calcining furnace. Typically and preferably, the ternary cathode materials are nickel-cobalt-manganese and nickel-cobalt-aluminum. Typical temperatures for such calcination processes are between 700°C and 1000°C, and the calcination process typically lasts between 10 and 18 hours.

[0008] The chemical reactions that occur during the roasting process can be described by the following formula, where M represents Ni (nickel), Mn (manganese), Co (cobalt), and / or Al (aluminum): M(OH)2+ 0.5 Li2CO3+ 0.25 O2= LiMO2+ 0.5 CO2+ H2O M(OH)2+ LiOH.H2O + 0.25 O2= LiMO2+ 2.5 H2O Specifically, oxygen plays a crucial role in this process because it facilitates oxidation, for example, in the oxidation of Ni. 2+ Oxidation to Ni 3+ However, if the dominant temperature in the calcining furnace is too high, Ni... 3+ The ternary cathode material faces the problem of decomposition. Therefore, it is prone to decomposition at high or excessively high temperatures. Consequently, the calcination process should maintain the temperature as low as possible to ensure the safety of Ni. 3+ Decomposition will not occur. Another objective is to provide a uniform temperature distribution and / or a uniform atmosphere within the furnace, allowing all raw materials in the furnace to be exposed to the same process conditions.

[0009] According to the present invention, the gaseous component in the atmosphere, preferably oxygen, is controlled to be injected into the roasting furnace in a closed-loop control manner (i.e., by closed-loop control) based on at least one process influence parameter being measured. Specifically, closed-loop control is automatically executed using a control module or the like.

[0010] Such process-influencing parameters can be any parameters that affect the process. Preferably, the at least one process-influencing parameter is selected from parameters characterizing the raw materials (e.g., a specific composition of the raw materials) and / or parameters characterizing the atmosphere (e.g., the present gaseous components (e.g., oxygen, carbon dioxide) and their specific ratios or humidity) and / or parameters characterizing the ternary cathode material (e.g., its specific composition). To measure such parameters, corresponding measuring and / or analyzing devices can be provided at appropriate locations.

[0011] Advantageously, gas injection lances are used to inject gas components into one or more zones of the calcining furnace. Specifically, the gas injection lances are mounted or positioned on the top or sidewall of the calcining furnace. In cases with more than one zone, one of these gas injection lances can be used for each zone. Alternatively, two or more of these gas injection lances can be used in one or more of these zones. The zones of the calcining furnace can be defined based on zones or sections with different process parameters, such as different temperatures and / or different speeds for moving the raw material through the calcining furnace. Such gas injection lances allow for very precise injection and thus enable a very uniform gas supply within the calcining furnace. However, zones can also be assigned to saggers present in the calcining furnace.

[0012] For example, one or more nozzles with a predetermined direction are provided for the gas injection gun (or each of several gas injection guns). The predetermined direction can preferably be selected between 0° and 90° relative to the longitudinal axis of the roasting furnace. This allows the atmosphere, and specifically the injected gas, to move in the desired direction. Additionally, turbulence or gas flow movement may be generated as a result.

[0013] Preferably, the gas components are supplied to the gas injection nozzle at a pressure between 0.5 bar and 10 bar. This allows selection of the velocity at which the gas exits the nozzle or its tip. For example, the velocity can be up to the speed of sound.

[0014] Advantageously, at least a portion of the gas injection lance (or each of several lances) is made of a ceramic-coated material such as steel (stainless steel or heat-resistant alloy, etc.), or the gas injection lance (or each of several lances) is made of ceramic. Such ceramics, especially when used as a coating, can be Al2O3, ZrO, SiC, etc., and in particular have very high purity so that the material, such as steel or other metal parts, does not come into any direct contact with the atmosphere in the furnace.

[0015] The method of this invention exposes the feedstock to oxygen very uniformly, as is required for such processes. For example, in the presence of multiple saggers in the furnace, each sagger is exposed to sufficient oxygen. However, without such a method, less contact between the feedstock and oxygen is observed in the inner saggers. In contrast, the feedstock in the outer saggers has a better chance of contact with oxygen. Consequently, the quality of roasting is less desirable for feedstock in the inner saggers or sagger lines. The feedstock layer thickness must be very thin. These disadvantages can be overcome by the method of this invention.

[0016] The method of this invention can also improve the quality of ternary cathode materials used in lithium-ion battery production, improve the quality stability of such ternary cathode materials, and maintain stable oxygen content (or the content of other gas components) to meet the calcination process requirements of specific materials in each zone of the furnace. Furthermore, it provides the possibility of increasing production capacity. Energy consumption and the volume of flowing gas can be reduced.

[0017] It should be noted that the method of the present invention can also be used to convert other raw materials into corresponding products using such a roasting furnace. For example, lithium iron phosphate (LFP) cathode materials or graphene anode materials can be prepared from the corresponding raw materials.

[0018] Another object of the present invention is an apparatus for preparing ternary cathode materials for lithium-ion batteries, the apparatus comprising a calcining furnace in which an atmosphere and raw materials to be calcined are provided. The apparatus further comprises an injection device for injecting gaseous components of the atmosphere into the calcining furnace, and a control device for controlling the injection of the gaseous components in a closed-loop control manner based on at least one measured process influence parameter. Measuring devices for measuring such parameters are provided. The injection device preferably comprises one or more gas injection nozzles having nozzles at their ends, the nozzles having a predetermined orientation relative to the longitudinal axis of the gas injection nozzles between 0° and 90°, preferably between 20° and 70°. Preferably, the apparatus is adapted to perform the method according to the invention.

[0019] For further embodiments and advantages of the device according to the invention, refer to the above statements to avoid repetition.

[0020] The invention will now be described further with reference to the accompanying drawings, which illustrate a preferred embodiment. Attached Figure Description

[0021] Figure 1 An apparatus is schematically shown that allows for the advantageous implementation of the method of the invention.

[0022] Figure 2 A more detailed schematic illustration of as Figure 1 The gas injection spray gun is part of the equipment.

[0023] Figure 3 Shown in different views Figure 2 Gas injection spray gun. Detailed Implementation

[0024] exist Figure 1 The image shows a preferred embodiment of the device 100 according to the invention. Such a device can be used and is suitable for implementing the method according to the invention. The device and the corresponding method will be described together below.

[0025] The apparatus 100 includes a roasting furnace 120, for example, a continuous roller hearth furnace, through which raw material 110 is roasted to obtain ternary cathode material 130. Raw material 110 can be fed into the roasting furnace 120, in which the raw material can move, for example, in a crucible line 125.

[0026] During the movement of the raw material within the baking furnace 120, the raw material is baked and transformed into the desired ternary cathode material 130. The transformation refers to the formula described above. At the end of the baking furnace 120, after the raw material has been completely transformed, the product, namely the ternary cathode material 130, can be removed from the furnace.

[0027] In the roasting furnace 120, an atmosphere is provided, which includes different gaseous components such as (pure or mostly pure) oxygen, air, and flue gas. By way of example, oxygen or oxygen feed is represented by the number a, air or air feed is represented by the number b, and flue gas (such as nitrogen) or flue gas feed is represented by the number c.

[0028] These gaseous components a, b, and c are fed into the interior of the roasting furnace 120 via a control device or control module 150. The flow rate of each of those gaseous components can be controlled by the control module 150.

[0029] In the illustrated embodiment, oxygen a is fed into the roasting furnace 120 via three gas injection nozzles 140, which, by way of example, are positioned in different regions 126 along the movement path of the raw material in the roasting furnace 120. The control module 150 may be adapted to distribute the oxygen a (i.e., its mass flow) supplied to the control module in a predetermined and variable ratio among the three gas injection nozzles 140.

[0030] In order to determine the current preferred ratio of oxygen flow between the gas injection nozzles 140 on the one hand, and the absolute oxygen mass flow of each gas injection nozzle on the other hand, different parameters affecting the roasting process can be measured and fed into the control module to establish closed-loop control.

[0031] By way of example, measuring and / or analyzing apparatus 111 for measuring or analyzing parameters characterizing raw material 110, measuring and / or analyzing apparatus 121 for measuring or analyzing parameters characterizing atmosphere, and measuring and / or analyzing apparatus 131 for measuring or analyzing ternary cathode material 130 are provided. Each of these apparatuses can feed the measurement or analysis results to control module 150 in the form of a signal, so that these results can be used to change (or maintain) the oxygen flow.

[0032] It should be noted that, if necessary or as a stopgap measure, the flow of air b and / or flue gas c can also be altered in the same manner. Furthermore, the pressure of the furnace atmosphere can be measured and controlled.

[0033] exist Figure 2 In the middle, it is shown in more detail and in perspective as Figure 1 The gas injection nozzle 140 is a part of the device 100. Figure 3 In the middle, a sectional view is shown. Figure 2 Gas injection nozzle 140.

[0034] Oxygen can be supplied to the gas injection nozzle 140 from the left end. As the nozzle 140 is fed into the roasting furnace 120, the oxygen can be transferred into the furnace. At the right end or input end 141, the gas injection nozzle 140 includes a nozzle 142. The nozzle 142 is provided in the form of a channel that is angled relative to the longitudinal direction or axis of the gas injection nozzle 140 (and preferably, also relative to other directions).

[0035] Using such nozzles (or several nozzles may be provided at the spray gun), oxygen can be injected into the roasting furnace at a desired speed and in a desired direction. The final direction of oxygen injection is determined by the orientation of the nozzle (or channel) 142 in the gas injection spray gun 140 and the orientation of the gas injection spray gun 140 in the roasting furnace 120.

[0036] As previously mentioned, the gas injection spray gun 140 may be made of ceramic material or steel (or stainless steel) coated with such ceramic. Essentially, only the portion of the spray gun that will be placed inside the baking oven needs to be coated with or made of ceramic or other similar material to prevent damage due to oxidation.

[0037] By providing a desired number of such spray guns and giving them a desired orientation (relative to their nozzles), a very uniform distribution of oxygen can be achieved in the baking oven 120 or its atmosphere. Therefore, ternary cathode materials can be prepared in a better and more efficient manner.

Claims

1. A method for preparing a ternary cathode material (130) for a lithium battery by calcining a raw material (110) in a calcining furnace (120), wherein an atmosphere is provided in the calcining furnace (120). in, The injection of gaseous component (a) of the atmosphere into the roasting furnace (120) is controlled in a closed-loop control manner based on at least one measured process influence parameter. The gas component (a) is injected into two or more regions (126) of the baking oven (120) using two or more gas injection nozzles (140), wherein one of the two or more gas injection nozzles is used for one of the regions (126); And the gas component (a) is distributed at a predetermined and variable ratio to each of two or more gas injection nozzles (140) by a control device (150). Each of the two or more gas injection nozzles (140) is provided at its end with one or more nozzles (142) in the form of a channel having a predetermined direction selected between 20° and 70° relative to the longitudinal axis of the calcining furnace (120), such that the gas component (a) injected through the nozzles is capable of generating turbulence, wherein the two or more gas injection nozzles (140) are respectively arranged in different regions of two or more areas (126) along the movement path of the calcining raw material in the calcining furnace (120), and inject the oxygen gas component (a) into the different regions of the two or more areas (126) respectively. The roasting furnace (120) is a continuous roller hearth furnace or a pusher furnace.

2. The method of claim 1, wherein the gas component is supplied to the gas injection nozzle (140) at a pressure between 0.5 bar and 10 bar.

3. The method according to claim 1 or 2, wherein the gas injection nozzle (140) is at least partially made of a ceramic-coated material or is made of ceramic.

4. The method according to any one of the preceding claims, wherein the at least one process influence parameter is selected from parameters characterizing the raw material (110) and / or the atmosphere and / or the ternary cathode material (130).

5. The method according to any one of the preceding claims, wherein the gaseous component (a) in the atmosphere is oxygen.

6. The method according to any one of the preceding claims, wherein the ternary cathode material (130) comprises nickel cobalt manganese or nickel cobalt aluminum.

7. An apparatus (100) for preparing ternary cathode material (130) for lithium-ion batteries, said apparatus comprising a baking oven (120) wherein an atmosphere and raw material (110) to be baked are provided. Its features The system includes an injection device (140) for injecting a gaseous component (a) of the atmosphere into the roasting furnace (120), and a control device (150) for controlling the injection of the gaseous component (a) in a closed-loop control manner based on at least one measured process influence parameter, wherein two or more gas injection nozzles (140) are used to inject the gaseous component (a) into two or more zones (126) of the roasting furnace (120), wherein one of the two or more gas injection nozzles is used for one of the two or more zones (126); and the control device (150) distributes the gaseous component (a) to the two or more gas injection nozzles at a predetermined and variable ratio. Each of the two or more gas injection nozzles (140) provides one or more nozzles (142) in the form of a channel having a predetermined direction selected between 20° and 70° relative to the longitudinal axis of the roasting furnace, such that the gas component (a) injected through the nozzles is capable of generating turbulence. The two or more gas injection nozzles (140) are respectively arranged in different regions of two or more areas (126) along the movement path of the roasting raw material in the roasting furnace (120) and inject the gas component (a) of oxygen into the different regions of the two or more areas (126), wherein a continuous roller hearth furnace or a pusher furnace is used as the roasting furnace (120).

8. The apparatus (100) according to claim 7, wherein the gas injection gun has a nozzle at its end, and / or the gas injection gun is mounted on the top or side wall of the roasting furnace.

9. The apparatus (100) according to claim 7 or 8 is also adapted to perform the method according to any one of claims 1 to 6.

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