Secondary battery positive electrode material calcining device

Abstract

A kind of secondary battery positive electrode material calcining device includes: calcining furnace, it includes the internal space with sequentially communicated temperature rising space, heat preservation space and cooling space;Multiple rollers are used to transport the refractory sagger containing positive electrode material from the temperature rising space via the heat preservation space to the cooling space;Multiple heaters are configured along the internal space;Multiple gas supply units are used to supply gas to the internal space;And multiple exhaust units are used to exhaust gas from the internal space, the cross-sectional area of the heat preservation space is less than the cross-sectional area of the temperature rising space and the cross-sectional area of the cooling space.

Description

Technical Field

[0001] This invention relates to a calcination apparatus for positive electrode materials of secondary batteries. Background Technology

[0002] Typically, a secondary battery cathode material calcination device is a device that calcines a refractory sagger containing the cathode material in a calcination furnace at a temperature of 400 to 1100 degrees Celsius, according to the material properties.

[0003] In the calcination process using a secondary battery cathode material calcination device, the cathode material contained in the refractory crucible will generate water vapor and carbon dioxide gas. Among them, the molecular weight of carbon dioxide gas is larger than that of oxygen or air used to regulate the atmosphere of the calcination furnace, so it is difficult to be discharged to the outside of the refractory crucible. There is a problem that the carbon dioxide gas remaining inside the refractory crucible will react chemically with the lithium oxide on the surface of the cathode active material formed by calcination to generate lithium carbonate.

[0004] For existing secondary battery cathode material calcination devices, in order to discharge the water vapor and carbon dioxide gas generated by the cathode material contained in the refractory sagger to the outside of the refractory sagger and to carry out the calcination reaction at the same time, oxygen and air are supplied to the bottom, top and sides of the calcination space where the refractory sagger is located.

[0005] However, for existing secondary battery cathode material calcination devices, the cross-sectional area of ​​the refractory sagger window through which gas flows from the outside of the refractory sagger into the inside of the refractory sagger is much smaller than the cross-sectional area of ​​the calcination space in which the refractory sagger is located. Therefore, there is a problem that only a very small amount of the total flow of gas through the cross-section of the calcination space flows into the inside of the refractory sagger. Summary of the Invention

[0006] Technical issues

[0007] One embodiment aims to provide a calcination apparatus for secondary battery cathode materials, which improves the discharge of carbon dioxide gas inside the refractory sagger by increasing the gas flow rate into the refractory sagger containing the secondary battery cathode material, thereby improving the calcination reaction of the secondary battery cathode material.

[0008] Technical solution

[0009] On one hand, a calcination apparatus for secondary battery cathode materials is provided, including a calcination furnace comprising an internal space having a heating space, a heat preservation space, and a cooling space connected in sequence; a plurality of rollers arranged along the internal space for conveying a refractory sagger containing cathode materials from the heating space through the heat preservation space to the cooling space; a plurality of heaters arranged along the internal space, with the plurality of rollers located between the plurality of heaters; a plurality of gas supply units connected to the internal space for supplying gas to the internal space; and a plurality of exhaust units connected to the internal space for exhausting gas from the internal space, wherein the cross-sectional area of ​​the heat preservation space is smaller than the cross-sectional areas of the heating space and the cooling space.

[0010] The first inner wall of the calcining furnace forming the heat-preserving space can be closer to the plurality of rollers than the second inner wall of the calcining furnace forming the heating space and the third inner wall of the calcining furnace forming the cooling space.

[0011] The plurality of heaters may include: a plurality of first heaters located inside the first inner wall; a plurality of second heaters spaced apart from the second inner wall and located in the heating space; and a plurality of third heaters spaced apart from the third inner wall and located in the cooling space.

[0012] The plurality of first heaters may have a smaller capacity than the plurality of second heaters and the plurality of third heaters.

[0013] The secondary battery cathode material calcination apparatus may include: a first isolation wall extending vertically from the second inner wall of the calcination furnace; and a second isolation wall extending vertically from the third inner wall of the calcination furnace, wherein the ends of the first isolation wall and the ends of the second isolation wall may be located on a horizontal line with the second inner wall.

[0014] The plurality of air supply units may include: a first air supply unit connected below the heating space; a second air supply unit connected below the insulation space; and a third air supply unit connected below the cooling space.

[0015] The plurality of exhaust units may include: a first exhaust unit connected above the heating space; and a second exhaust unit connected above the cooling space.

[0016] Invention Effects

[0017] According to one embodiment, a calcination apparatus for secondary battery cathode materials can be provided, which improves the discharge of carbon dioxide gas inside the refractory crucible by increasing the gas flow rate into the refractory crucible containing the secondary battery cathode material, thereby improving the calcination reaction of the secondary battery cathode material. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of a secondary battery cathode material calcination apparatus according to one embodiment.

[0019] Figure 2 These are schematic diagrams of the proportional section and the experimental section.

[0020] Figure 3 It is shown Figure 2 The table shows the experimental results for the comparative and experimental cross sections. Detailed Implementation

[0021] In the following, embodiments of the present invention will be described in detail with reference to the accompanying drawings to enable those skilled in the art to practice the invention. The present invention can be implemented in various different ways and is not limited to the embodiments described herein.

[0022] Parts unrelated to the description have been omitted from the accompanying drawings in order to clearly describe the invention. The same reference numerals are used throughout the specification to denote the same or similar components.

[0023] Furthermore, throughout the specification, when a section is described as "including" a component, unless there is an explicit statement to the contrary, it means that other components may also be included, not that other components are excluded.

[0024] In the following text, reference will be made to Figure 1 A calcination apparatus for secondary battery cathode material is described according to one embodiment.

[0025] Figure 1 This is a schematic diagram of a secondary battery cathode material calcination apparatus according to one embodiment.

[0026] Reference Figure 1 According to one embodiment of the secondary battery positive electrode material calcination apparatus, a refractory sagger SA containing secondary battery positive electrode material is heated in the internal space 110 of a calcination furnace 100, thereby calcining the secondary battery positive electrode material contained in the refractory sagger SA. In one embodiment, the refractory sagger SA is stacked in multiple layers, but it is not limited to this and can be set as a single layer.

[0027] The calcination device for secondary battery cathode materials includes a heating section A1, a heat preservation section A2, and a cooling section A3.

[0028] The heating section A1 is the section where the secondary battery positive electrode material contained in the refractory crucible SA is heated to a set temperature (e.g., 400 to 1100 degrees Celsius) according to its characteristics.

[0029] Insulation section A2 is the section that maintains the set temperature.

[0030] Cooling section A3 is the section that cools at a set temperature.

[0031] The secondary battery cathode material calcination device includes a calcination furnace 100 forming a heating section A1, a heat preservation section A2, and a cooling section A3, multiple rollers 200, multiple heaters 300, multiple gas supply units 400, and multiple exhaust units 500.

[0032] The calcining furnace 100 includes an internal space 110, a first inner wall 120, a second inner wall 130, a third inner wall 140, a first isolation wall 150, and a second isolation wall 160.

[0033] The internal space 110 is a space for the refractory crucible SA containing the positive electrode material to move in one direction, and includes a heating space S1, a heat preservation space S2, and a cooling space S3 that are connected in one direction in sequence.

[0034] The heating space S1 corresponds to the heating section A1. The cross-sectional area of ​​the heating space S1 is larger than the cross-sectional area of ​​the insulation space S2.

[0035] The insulation space S2 is connected to the heating space S1 and corresponds to the insulation section A2. The cross-sectional area of ​​the insulation space S2 is smaller than the cross-sectional area of ​​the heating space S1 and the cross-sectional area of ​​the cooling space S3.

[0036] Cooling space S3 is connected to insulation space S2 and corresponds to cooling section A3. The cross-sectional area of ​​cooling space S3 is larger than that of insulation space S2.

[0037] The first inner wall 120 forms an insulation space S2. The first inner wall 120 is the inner wall of the lower wall, upper wall, and side wall that form the insulation space S2. The first height L1 of the insulation space S2 formed by the first inner wall 120 is less than the second height L2 of the heating space S1 formed by the second inner wall 130 and the third height L3 of the cooling space S3 formed by the third inner wall 140.

[0038] The first inner wall 120 is closer to the roller 200 than the second inner wall 130 and the third inner wall 140.

[0039] The second inner wall 130 forms a heating space S1. The second inner wall 130 is the inner wall of the lower wall, upper wall, and side wall that form the heating space S1. The second height L2 of the heating space S1 formed by the second inner wall 130 is greater than the first height L1 of the heat preservation space S2 formed by the first inner wall 120.

[0040] The second inner wall 130 is further away from the roller 200 than the first inner wall 120.

[0041] The third inner wall 140 forms a cooling space S3. The third inner wall 140 is the inner wall of the lower wall, upper wall, and side wall that form the cooling space S3. The third height L3 of the cooling space S3 formed by the third inner wall 140 is greater than the first height L1 of the heat preservation space S2 formed by the first inner wall 120.

[0042] The third inner wall 140 is further away from the roller 200 than the first inner wall 120.

[0043] The first isolation wall 150 extends vertically from the second inner wall 130. The first isolation wall 150 divides the heating space S1, and the temperature can rise along the space divided by the first isolation wall 150.

[0044] The second isolation wall 160 extends vertically from the third inner wall 140. The second isolation wall 160 divides the cooling space S3, and the temperature can drop along the space divided by the second isolation wall 160.

[0045] The ends of the first isolation wall 150 and the second isolation wall 160, along with the second inner wall 130, can be located on a virtual horizontal line. That is, the first isolation wall 150, the second inner wall 130, and the second isolation wall 160 can be located on the same horizontal line.

[0046] Multiple rollers 200 are unidirectionally arranged along the internal space 110 of the calcining furnace 100. The multiple rollers 200 transport the refractory sagger SA containing the positive electrode material from the heating space S1 inside the calcining furnace 100 to the cooling space S3 via the heat preservation space S2.

[0047] The plurality of heaters 300 include a plurality of upper heaters and a plurality of lower heaters unidirectionally arranged along the interior space 110, with a plurality of rollers 200 located between the plurality of upper heaters and the plurality of lower heaters.

[0048] The plurality of heaters 300 include a plurality of first heaters 310, a plurality of second heaters 320, and a plurality of third heaters 330.

[0049] Multiple first heaters 310 are located inside the first inner wall 120, separated by an insulation space S2. The multiple first heaters 310 have a smaller capacity than the multiple second heaters 320.

[0050] Multiple second heaters 320 are spaced apart from the second inner wall 130 and located in the heating space S1.

[0051] Multiple third heaters 330 are spaced apart from the third inner wall 140 and located in the cooling space S3.

[0052] Multiple gas supply units 400 are connected to the interior space 110 to supply gas GA to the interior space 110. The gas GA supplied by the gas supply units 400 may include air and oxygen, but is not limited to these.

[0053] The multiple gas supply units 400 include a first gas supply unit 410, a second gas supply unit 420, and a third gas supply unit 430.

[0054] The first gas supply unit 410 is connected below the heating space S1 and supplies gas GA to the heating space S1. The gas GA supplied from the first gas supply unit 410 to the heating space S1 can selectively pass through the heating space S1, the heat preservation space S2, and the cooling space S3 before being discharged from the first exhaust unit 510 or the second exhaust unit 520.

[0055] The second gas supply unit 420 is connected below the heat preservation space S2 and supplies gas GA to the heat preservation space S2. The gas GA supplied from the second gas supply unit 420 to the heat preservation space S2 can selectively pass through the heating space S1, the heat preservation space S2, and the cooling space S3 before being discharged from the first exhaust unit 510 or the second exhaust unit 520.

[0056] The third gas supply unit 430 is connected below the cooling space S3 and supplies gas GA to the cooling space S3. The gas GA supplied from the third gas supply unit 430 to the cooling space S3 can selectively pass through the heating space S1, the heat preservation space S2, and the cooling space S3 before being discharged from the first exhaust unit 510 or the second exhaust unit 520.

[0057] Multiple exhaust units 500 are connected to the internal space 110 and exhaust gas GA from the internal space 110. In addition to the air and oxygen supplied by the air supply unit 400, the gas GA exhausted by the exhaust unit 500 may also include carbon dioxide gas and water vapor exhausted from the refractory crucible SA, but is not limited thereto.

[0058] The multiple exhaust units 500 include a first exhaust unit 510 and a second exhaust unit 520.

[0059] The first exhaust unit 510 is connected above the heating space S1 and exhausts gas GA from the heating space S1.

[0060] The second exhaust unit 520 is connected above the cooling space S3 and exhausts gas GA from the cooling space S3.

[0061] As described above, in a secondary battery cathode material calcination apparatus according to one embodiment, the cross-sectional area of ​​the heat preservation space S2 is smaller than that of the heating space S1 and the cooling space S3. Therefore, relative to the cooling space S3 and the heating space S1, the flow rate of gas GA flowing from the outside of the refractory sagger SA into the interior of the refractory sagger SA increases in the heat preservation space S2, thereby improving the discharge of carbon dioxide gas inside the refractory sagger SA and improving the calcination reaction of the secondary battery cathode material contained in the refractory sagger SA.

[0062] The inventors of this invention have determined which section of the internal space 110 in the heating section A1, the heat preservation section A2, and the cooling section A3 of the secondary battery cathode material calcination apparatus is more effective in reducing its cross-sectional area. From the calcination reaction of the cathode material contained in the refractory crucible SA, most of the carbon dioxide gas produced by the cathode material originates in the heating section A1, and the amount of carbon dioxide gas produced from the heat preservation section A2 onwards is significantly reduced. Therefore, according to one embodiment of the secondary battery cathode material calcination apparatus, the cross-sectional area of ​​the heat preservation space S2 corresponding to the heat preservation section A2 is smaller than the cross-sectional areas of the heating space S1 and the cooling space S3, in order to improve the discharge of carbon dioxide gas inside the refractory crucible SA.

[0063] Furthermore, the inventors of this invention believe that, in order for the cross-sectional area of ​​the heat preservation space S2 to be smaller than the cross-sectional areas of the heating space S1 and the cooling space S3, if the first inner wall 120 of the calcining furnace 100 is arranged on the same horizontal line as the first isolation wall 150 and the second isolation wall 160, the first heater 310 cannot be located in the heat preservation space S2 of the calcining furnace 100, and heat preservation of the heat preservation space S2 will become difficult. In response, based on confirmation of the actual heat generation of the upper and lower heaters during the operation of the mass production calcining furnace, when the set temperature conditions are reached and the temperature is maintained normally in the actual mass production calcining process, the internal temperature is maintained even if the heater hardly works in the heat preservation section without the isolation wall. Based on this, according to one embodiment of the secondary battery cathode material calcining apparatus, although the cross-sectional area of ​​the heat preservation space S2 is smaller than the cross-sectional areas of the heating space S1 and the cooling space S3, the small-capacity first heater 310 is located inside the first inner wall 120 forming the heat preservation space S2, thus achieving heat preservation of the heat preservation space S2.

[0064] In other words, according to one embodiment of the secondary battery cathode material calcination apparatus, since the first heater 310, which has a capacity smaller than that of the second heater 320 and the third heater 330, is located inside the first inner wall 120, the cross-sectional area of ​​the heat preservation space S2 can be minimized to the maximum extent, thereby maximizing the gas flow rate into the refractory crucible SA in the heat preservation space S2.

[0065] In the following text, reference will be made to Figure 2 and Figure 3The experiment described confirms the effectiveness of the secondary battery cathode material calcination apparatus according to one embodiment.

[0066] Figure 2 These are schematic diagrams of the proportional section and the experimental section. Figure 2 (A) shows a comparative section. Figure 2 (B) shows the cross section of the experimental example.

[0067] Figure 2 The comparative section CS1 shown in (A) represents the cross-section of the insulation space with the same cross-sectional area as the heating space and the cooling space.

[0068] Figure 2 The experimental example section CS2 shown in (B) represents the cross-section of the insulation space whose cross-sectional area is smaller than that of the heating space and the cooling space. The experimental example section can be the cross-section of the insulation space when the ends of the first inner wall and the first isolation wall and the second isolation wall forming the insulation space are on the same horizontal line.

[0069] Reference Figure 2 After calculating the flow rates of gas GA into the comparative section CS1 and the experimental section CS2 at the same flow rate using computational fluid dynamics, the proportion of gas flow rates through the window WI section on the side of the refractory crucible SA was compared. Furthermore, based on this difference in inflow gas flow rates, the concentration of exhaust gas (CO2) affecting the calcination reaction of the cathode material contained in the refractory crucible SA was also compared.

[0070] Figure 3 It is shown Figure 2 The table shows the experimental results for the comparative and experimental cross sections.

[0071] Reference Figure 3 According to fluid analysis results, in the comparative cross section, the area of ​​the side window of the refractory sagger is only 4.25% of the total area. The flow rate into the refractory sagger is 3.2% relative to the total supply flow rate, which is less than the area ratio of the side window of the refractory sagger.

[0072] In the experimental cross-section, the area of ​​the side window of the refractory sagger increased to 18.9% of the total area, and the flow rate into the refractory sagger also increased to 16.6% relative to the total supply flow rate.

[0073] As a result, compared with the comparative example, the partial pressure of the exhaust gas (CO2) from the calcination reaction inside the refractory crucible in the experimental example was reduced to less than half. This result confirms that, under the same supply flow rate, reducing the cross-sectional area of ​​the experimental example increases the flow rate inside the refractory crucible and reduces the concentration of the exhaust gas, thereby improving the calcination reaction of the cathode material contained within the refractory crucible.

[0074] As described above, the present invention provides a calcination apparatus for secondary battery cathode materials, which improves the discharge of carbon dioxide gas inside the refractory sagger by increasing the gas flow rate into the refractory sagger containing the secondary battery cathode material, and at the same time improves the calcination reaction of the secondary battery cathode material contained in the refractory sagger.

[0075] In addition, under the same gas supply flow rate, the calcination reaction conditions are improved. The same calcination reaction can be carried out by increasing the amount of cathode material (increasing production) or by using a smaller gas supply flow rate relative to the same amount of cathode material (reducing operating costs), ultimately providing a secondary battery cathode material calcination device that reduces the production cost of cathode materials.

[0076] Although embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements made by those skilled in the art using the basic concepts of the present invention as defined in the claims also fall within the scope of the present invention.

[0077] Explanation of reference numerals in the attached figures

[0078] S1: Heating space, S2: Insulation space, S3: Cooling space, 100: Calcination furnace, 200: Drum, 300: Heater, 400: Gas supply unit, 500: Exhaust unit.

Claims

1.A secondary battery positive electrode material calcination apparatus comprising: a calcination furnace including an internal space having a temperature increasing space formed by a second inner wall, a temperature maintaining space formed by a first inner wall, and a cooling space formed by a third inner wall, which are sequentially communicated; a plurality of rollers configured along the internal space for transporting a refractory sagger containing a positive electrode material from the temperature increasing space to the cooling space via the temperature maintaining space; a plurality of heaters configured along the internal space, the plurality of rollers being located between the plurality of heaters; a plurality of gas supply units connected to the internal space for supplying gas to the internal space; and a plurality of gas exhaust units connected to the internal space for exhausting gas from the internal space, a cross-sectional area of the temperature maintaining space being smaller than cross-sectional areas of the temperature increasing space and the cooling space, wherein the plurality of gas supply units include: a first gas supply unit connected to a lower portion of the temperature increasing space; a second gas supply unit connected to a lower portion of the temperature maintaining space; and a third gas supply unit connected to a lower portion of the cooling space, wherein the first, second, and third gas supply units are in communication with the temperature increasing space, the temperature maintaining space, and the cooling space, and wherein the plurality of heaters include: a plurality of first heaters located inside the first inner wall; a plurality of second heaters spaced apart from the second inner wall, located in the temperature increasing space; and a plurality of third heaters spaced apart from the third inner wall, located in the cooling space, wherein the plurality of first heaters have a capacity smaller than those of the plurality of second heaters and the plurality of third heaters. 2.The secondary battery positive electrode material calcination apparatus according to claim 1, wherein the first inner wall is closer to the plurality of rollers than the second and third inner walls. 3.The secondary battery positive electrode material calcination apparatus according to claim 2, further comprising: a first partition wall extending from the second inner wall of the calcination furnace in a vertical direction; and a second partition wall extending from the third inner wall of the calcination furnace in a vertical direction, an end portion of the first partition wall and an end portion of the second partition wall being located on a horizontal line with the first inner wall. 4.The secondary battery positive electrode material calcination apparatus according to claim 1, wherein the plurality of gas exhaust units include: a first gas exhaust unit connected to an upper portion of the temperature increasing space; and a second gas exhaust unit connected to an upper portion of the cooling space. ​ ​

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