A tunnel kiln

Abstract

This utility model discloses a tunnel kiln, comprising: a kiln body, with a heating zone, a constant temperature zone, and a cooling zone sequentially arranged along a first direction; a heating system located in the heating zone and the constant temperature zone for heating the heating zone and the constant temperature zone; a cooling system located in the cooling zone for cooling the cooling zone; and an exhaust system including an exhaust fan, an exhaust pipe, a heat tracing element, and a waste gas treatment component. The waste gas treatment component is connected to the outlet end of the exhaust fan, the inlet end of the exhaust fan is connected to the outlet end of the exhaust pipe, the inlet end of the exhaust pipe is connected to both the heating zone and the constant temperature zone, and the heat tracing element is located on the outer periphery of the exhaust pipe for heating the exhaust pipe. This utility model can avoid the condensation and backflow of battery pack drying decomposition products, improving the efficiency and effect of battery pack pretreatment.

Description

Technical Field

[0001] This utility model relates to the technical field of battery recycling equipment, and in particular to a tunnel kiln. Background Technology

[0002] The pretreatment and recycling process for lithium iron phosphate battery packs generally consists of two parts: the first part is obtaining individual cells from the battery pack; the second part is crushing, drying, and sorting the individual cells to obtain battery powder and other products. The entire pretreatment process involves structural adhesive destruction, electrolyte and binder drying, and exhaust gas emission. Specifically, for the treatment of electrolyte and binder in the crushed battery material, the binder and other waste materials are dried and decomposed into gases such as alkanes and olefins, which are then emitted into the exhaust gas treatment device. However, during the exhaust gas emission process, due to the high boiling points of the substances produced by the decomposition of binders, backflow of decomposition products often occurs, leading to poor pretreatment results or low efficiency, and even affecting the subsequent battery powder recovery rate. Utility Model Content

[0003] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention proposes a tunnel kiln.

[0004] The solution to the technical problem of this utility model is: A tunnel kiln, comprising: The kiln body is provided with a heating zone, a constant temperature zone and a cooling zone in sequence along the first direction; A heating system is provided in the heating zone and the constant temperature zone for heating the heating zone and the constant temperature zone; A cooling system, located in the cooling zone, is used to cool the cooling zone; An exhaust system includes an exhaust fan, an exhaust pipe, a heat tracing element, and a waste gas treatment component. The waste gas treatment component is connected to the outlet end of the exhaust fan, the inlet end of the exhaust fan is connected to the outlet end of the exhaust pipe, the inlet end of the exhaust pipe is connected to the heating zone and the constant temperature zone, and the heat tracing element is disposed on the outer periphery of the exhaust pipe and is used to heat the exhaust pipe.

[0005] This invention has at least the following beneficial effects: The battery pack enters the kiln along the first direction and passes through the heating zone, the constant temperature zone, and the cooling zone in sequence. Under the action of the heating zone and the constant temperature zone, the electrolyte, binder, and other waste materials of the battery pack decompose and form waste gas. Under the action of the exhaust system, the waste gas is discharged from the kiln and fed into the waste gas treatment component for recycling, thus achieving separation from recyclable materials such as battery powder. Since the exhaust pipe in the exhaust system is equipped with a heat tracing element on the outside, the exhaust pipe maintains a high temperature under the action of the heat tracing element, keeping the waste gas in the exhaust pipe in a gaseous state. This avoids the waste material from condensing and flowing back into the kiln, and avoids the waste material from repeatedly undergoing gaseous and liquid conversion. This improves the decomposition efficiency, enhances the pretreatment effect of the battery pack, and is more conducive to the subsequent recycling of materials such as battery powder.

[0006] As a further improvement to the above technical solution, the exhaust system also includes a heat insulation component, which covers the outer periphery of the exhaust pipe, and the heat tracing element is disposed between the heat insulation component and the exhaust pipe. The heat insulation component can wrap and insulate the exhaust pipe and the heat tracing element, reducing heat loss.

[0007] As a further improvement to the above technical solution, the heating zone and the constant temperature zone are respectively connected to multiple exhaust pipes, which are evenly distributed along the first direction. Multiple exhaust pipes can improve the exhaust gas discharge efficiency, thereby improving the drying and decomposition efficiency of the battery pack.

[0008] As a further improvement to the above technical solution, the exhaust system also includes an exhaust pipe. The inlet end of the exhaust gas treatment component is connected to the outlet end of the exhaust fan through the exhaust pipe, and the heat tracing element is provided on the outer periphery of the exhaust pipe. The heat tracing element located outside the exhaust pipe can heat the exhaust pipe, allowing the exhaust gas to enter the exhaust gas treatment component in a gaseous state, thus preventing the exhaust gas from condensing and flowing back to the exhaust fan.

[0009] As a further improvement to the above technical solution, the tunnel kiln also includes: The nitrogen system includes a nitrogen supply component and multiple nitrogen pipes. The inlet ends of the nitrogen pipes are connected to the outlet ends of the nitrogen supply component, and the outlet ends of the nitrogen pipes are connected to the heating zone, the constant temperature zone, and the cooling zone.

[0010] The nitrogen system keeps the kiln in a nitrogen-protected atmosphere, ensuring the safety of the battery pack drying process.

[0011] As a further improvement to the above technical solution, the nitrogen system also includes an oxygen detection element, which is installed inside the kiln and used to detect the oxygen content inside the kiln. The oxygen detection element assists operators in detecting the oxygen content inside the kiln, further ensuring the safety of the drying process.

[0012] As a further improvement to the above technical solution, the cooling system includes a cold water pipe and a water pump. The cold water pipe is laid on top of the cooling zone, and the water pump is located on the outside of the kiln body. The outlet and inlet ends of the cold water pipe extend out of the kiln body, respectively. The outlet end of the water pump is connected to the inlet end of the cold water pipe, and the inlet end of the water pump is connected to the outlet end of the cold water pipe. Cooling water, driven by the water pump, flows through the cold water pipe into and out of the cooling zone of the kiln body, carrying away the heat from the battery packs moving to the cooling zone, thus achieving a cooling effect.

[0013] As a further improvement to the above technical solution, the wall of the kiln body includes a refractory layer, a thermal insulation layer, and an impact-resistant layer, which are arranged sequentially from the inside to the outside. This three-layer structure enables the kiln body to possess excellent refractory, thermal insulation, and impact-resistant properties, further ensuring the safety of the drying process and improving the drying and decomposition effect of the battery pack.

[0014] As a further improvement to the above technical solution, the tunnel kiln also includes: The conveying system includes a kiln car, a power unit, a first track, a second track, a first shuttle lane, and a second shuttle lane. The first track passes through the kiln body in a first direction, and the second track is located on the outside of the kiln body. The two ends of the first shuttle lane are respectively connected to the inlet end of the first track and the outlet end of the second track. The two ends of the second shuttle lane are respectively connected to the outlet end of the first track and the inlet end of the second track. The first track, the second shuttle lane, the second track, and the first shuttle lane together form a turning lane. The power unit is driven by the kiln car to drive the kiln car to move along the turning lane.

[0015] Driven by the power unit, the kiln car carrying the battery pack moves along the rotary track, realizing the automatic entry and exit of the battery pack into and out of the kiln body, improving the automation level of the battery pack drying process. In addition, a second track is set on the outside of the kiln body, which makes it easier for operators to load and unload materials after the kiln car enters the second track.

[0016] As a further improvement to the above technical solution, the kiln body is provided with multiple movable chambers, each of which extends through both ends of the kiln body along a first direction. The movable chambers are used for the kiln car to move within the kiln body. With this configuration, the tunnel kiln can simultaneously dry battery packs entering different movable chambers, improving drying efficiency. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this utility model, the accompanying drawings used in the description of the embodiments will be briefly explained below. Obviously, the described drawings are only a part of the embodiments of this utility model, and not all of them. Those skilled in the art can obtain other design schemes and drawings based on these drawings without creative effort.

[0018] Figure 1 This is a front view of the kiln body according to an embodiment of the present utility model; Figure 2 This is a top view of the tunnel kiln according to an embodiment of the present utility model; Figure 3 This is a schematic diagram of the exhaust system according to an embodiment of the present invention; Figure 4 This is a cross-sectional view of the exhaust pipe according to an embodiment of the present utility model; Figure 5 This is a cross-sectional view of the kiln body according to an embodiment of the present invention.

[0019] Figure label: 100. Kiln body; 110. Heating zone; 120. Constant temperature zone; 130. Cooling zone; 140. Moving chamber; 150. Refractory layer; 160. Insulation layer; 170. Impact-resistant layer; 200. Conveying system; 210. Kiln car; 220. Hydraulic station; 230. First track; 240. Second track; 241. Loading area; 242. Unloading area; 250. First shuttle lane; 260. Second shuttle lane; 270. Maintenance lane; 300. Cooling system; 400. Exhaust system; 410. Exhaust fan; 420. Exhaust pipe; 430. Heat tracing element; 440. Insulation component; 450. Waste gas treatment component; 460. Waste gas pipe; 500. Nitrogen system; 600. Heating system; 700, replacement room; 800, battery pack. Detailed Implementation

[0020] The embodiments of this utility model are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this utility model, and should not be construed as limiting this utility model.

[0021] In the description of this utility model, the orientation descriptions, such as up, down, front, back, left, right, etc., are based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0022] In the description of this utility model, "several" means one or more, "multiple" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. If "first" or "second" is used in the description, it is only for the purpose of distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0023] In the description of this utility model, unless otherwise explicitly defined, terms such as "setting," "installation," and "connection" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this utility model in conjunction with the specific content of the technical solution.

[0024] Obviously, the described embodiments are only some, not all, of the embodiments of this utility model. Other embodiments obtained by those skilled in the art based on the embodiments of this utility model without creative effort are all within the scope of protection of this utility model. The various technical features of this utility model can be combined interactively without contradicting each other.

[0025] Reference Figure 1 , Figure 2 and Figure 5 This utility model embodiment proposes a tunnel kiln, which can be applied in the pretreatment process of lithium iron phosphate battery pack 800 recycling. It can realize the drying of battery pack 800 and exhaust gas emission, and can avoid the backflow of drying decomposition products, improve the waste decomposition efficiency, and improve the battery powder recovery rate.

[0026] Specifically, the tunnel kiln includes a kiln body 100, a heating system 600, a cooling system 300, and an exhaust system 400. The kiln body 100 is arranged along a first direction, and a heating zone 110, a constant temperature zone 120, and a cooling zone 130 are arranged sequentially along the first direction. It can be understood that the kiln car 210 carrying the battery pack 800 can pass through the heating zone 110, the constant temperature zone 120, and the cooling zone 130 sequentially along the first direction within the kiln body 100, thereby achieving drying and decomposition.

[0027] A heating system 600 is disposed within a heating zone 110 and a constant temperature zone 120, and includes multiple heating elements. The heating elements located in the heating zone 110 are used to raise the temperature of the battery pack 800 within the heating zone 110, ensuring sufficient heating to decompose the structural adhesive, electrolyte, binder, and separator within the battery pack 800. The heating elements located in the constant temperature zone 120 are used to maintain the temperature of the battery pack 800 within the constant temperature zone 120, allowing the waste materials such as structural adhesive, electrolyte, binder, and separator to continue decomposing, thereby increasing the purity of the remaining battery powder in the battery pack 800.

[0028] The cooling system 300 is installed in the cooling zone 130 and can cool the cooling zone 130 and the battery pack 800 entering the cooling zone 130 so that the battery pack 800 can enter the next process for processing and recycling.

[0029] It is worth noting that, referring to Figure 3 and Figure 4 The exhaust system 400 includes an exhaust fan 410, an exhaust pipe 420, a heat tracing element 430, and a waste gas treatment component 450. The outlet end of the exhaust pipe 420 is connected to the inlet end of the exhaust fan 410, the waste gas treatment component 450 is connected to the outlet end of the exhaust fan 410, the inlet end of the exhaust pipe 420 is connected to the heating zone 110 and the constant temperature zone 120 respectively, and the heat tracing element 430 is disposed on the outer periphery of the exhaust pipe 420.

[0030] Understandably, the structural adhesive, electrolyte, binder, and separator of the battery pack 800, as waste materials in the battery recycling process, are dried in the heating zone 110 and the constant temperature zone 120, and directly decomposed into gases such as alkanes and olefins. Under the action of the exhaust fan 410, these gases are discharged from the kiln body 100 through the exhaust pipe 420, and then fed into the waste gas treatment component 450 for incineration or other tail gas treatment methods, thereby improving the battery powder recovery rate.

[0031] Because the substances produced by the decomposition of diaphragms, binders, etc., have high boiling points, the gas has already left the high-temperature environment of the heating zone 110 or the constant-temperature zone 120 when it enters the exhaust pipe 420, resulting in condensation and reflux. In this embodiment, a heating element 430 is provided on the outer periphery of the exhaust pipe 420 to heat the exhaust pipe 420 and maintain a high-temperature environment inside the exhaust pipe 420, thereby keeping the substances produced by the decomposition of waste in a gaseous state and achieving the effect of avoiding condensation and reflux.

[0032] In addition, by using the tunnel kiln of this embodiment to pre-treat the battery pack 800, the battery pack 800 does not need to be mechanically crushed before drying and decomposition, thereby reducing dust overflow and preventing the dust from carrying electrolyte and entering the dust removal system.

[0033] In some embodiments, refer to Figure 4 The exhaust system 400 also includes an insulation component 440, which covers the outer periphery of the exhaust pipe 420. A heat tracing element 430 is disposed between the insulation component 440 and the exhaust pipe 420. By wrapping the exhaust pipe 420 and the heat tracing element 430 with the insulation component 440, more heat can be transferred to the exhaust pipe 420, reducing heat loss from the heat tracing element 430, thereby reducing energy consumption while achieving the preset heating effect.

[0034] In some embodiments, the exhaust pipe 420 is made of 316 stainless steel, the heating element 430 is a heating wire, and the insulation component 440 is made of rock wool. The heating wire is attached to the exhaust pipe 420, and the exhaust pipe 420 and the heating wire are wrapped and insulated by the rock wool insulation component 440 to prevent the electrolyte from condensing and flowing back inside the exhaust pipe 420. During the exhaust process, the heating element 430 heats the exhaust pipe 420 by electric heating.

[0035] In some embodiments, the heating zone 110 and the constant temperature zone 120 are respectively connected to multiple exhaust pipes 420, which are evenly distributed along a first direction, thereby enabling exhaust to be discharged from the entire heating zone 110 and the entire constant temperature zone 120, improving the exhaust efficiency and thus improving the pretreatment efficiency of the battery pack 800.

[0036] In some embodiments, refer to Figure 3 The exhaust system 400 also includes an exhaust pipe 460. The inlet end of the exhaust gas treatment component 450 is connected to the outlet end of the exhaust fan 410 via the exhaust pipe 460. A heat tracing element 430 is also provided on the outer periphery of the exhaust pipe 460. It is understood that the heat tracing element 430 on the outer periphery of the exhaust pipe 460 can heat the exhaust pipe 460, keeping the waste in a gaseous state as it enters the exhaust gas treatment component 450, thus preventing the decomposition products of waste such as electrolyte from condensing in the exhaust pipe 460 and causing backflow to the exhaust fan 410.

[0037] It is understandable that the exhaust gas treatment component 450 can be an incinerator, etc.

[0038] In some embodiments, an insulation element 440 is also provided on the outer periphery of the exhaust pipe 460. The insulation element 440 wraps and insulates the heat tracing element 430 and the exhaust pipe 460, thereby preventing the gas formed by the decomposition of electrolyte and other substances from condensing and flowing back into the exhaust pipe 460.

[0039] In some embodiments, refer to Figure 1The tunnel kiln also includes a nitrogen system 500, which includes a nitrogen supply component and multiple nitrogen pipes. The inlet end of the nitrogen pipes is connected to the outlet end of the nitrogen supply component, and the outlet end of the nitrogen pipes is connected to the heating zone 110, the constant temperature zone 120, and the cooling zone 130, respectively.

[0040] Nitrogen pipes are arranged at the bottom of the kiln body 100 and are distributed throughout the entire kiln body 100. Nitrogen is introduced into the heating zone 110, the constant temperature zone 120 and the cooling zone 130 through the nitrogen supply components and nitrogen pipes. This allows the battery pack 800 to be in an inert environment protected by nitrogen throughout the drying process, preventing oxidation reaction and improving the safety of the decomposition process.

[0041] It is understandable that, since the battery pack 800 is pretreated using the tunnel kiln of this embodiment, the crushing step before drying is omitted, the entire pretreatment process is simpler, the process flow is shortened, and the amount of nitrogen required in the pretreatment process can be reduced.

[0042] In some embodiments, the nitrogen system 500 further includes an oxygen detection element disposed within the kiln body 100 and used to detect the oxygen content within the kiln body 100. The oxygen detection element is electrically connected to a nitrogen supply component, which is configured to adjust the nitrogen output based on the oxygen content detected by the oxygen detection element.

[0043] Understandably, when the oxygen content inside the kiln 100 is too high, the inert environment inside the kiln 100 is disrupted, requiring the introduction of nitrogen into the kiln 100 or the repair of the nitrogen pipe and nitrogen supply components.

[0044] In some embodiments, the cooling system 300 of the tunnel kiln reduces the temperature within the cooling zone 130 using water cooling. The cooling system 300 includes a cold water pipe and a water pump. The cold water pipe is laid on top of the cooling zone 130, and the water pump is located on the outside of the kiln body 100. The outlet and inlet ends of the cold water pipe extend to the outside of the kiln body 100 and are connected to the water pump, forming a loop. Specifically, the outlet end of the water pump is connected to the inlet end of the cold water pipe, and the inlet end of the water pump is connected to the outlet end of the cold water pipe.

[0045] Under the action of the water pump, cooling water can enter and exit the cooling zone 130 of the kiln body 100 through the cold water pipe, and carry away the heat in the kiln by heat exchange in the cooling zone 130, thus achieving the effect of cooling.

[0046] In some embodiments, refer to Figure 5The wall of the kiln body 100 comprises a three-layer structure, consisting of a refractory layer 150, an insulation layer 160, and an impact-resistant layer 170, from the inside out. Specifically, the innermost refractory layer 150 is made of high-alumina bricks, offering superior fire resistance and corrosion resistance, effectively resisting HF corrosion; the middle insulation layer 160 is made of lightweight high-alumina bricks, providing both corrosion resistance and insulation, effectively resisting HF corrosion; and the outermost impact-resistant layer 170 is made of fired red bricks, providing impact resistance and effectively protecting the inner layers.

[0047] In some embodiments, refer to Figure 1 , Figure 2 and Figure 5 The tunnel kiln also includes a conveying system 200, which comprises a kiln car 210, a power unit, a first track 230, a second track 240, a first shuttle lane 250, and a second shuttle lane 260. The first track 230 runs along a first direction through the kiln body 100. The second track 240 is located on the outside of the kiln body 100. The two ends of the first shuttle lane 250 are connected to the entrance end of the first track 230 and the exit end of the second track 240, respectively. The two ends of the second shuttle lane 260 are connected to the exit end of the first track 230 and the entrance end of the second track 240, respectively. Thus, the first track 230, the second track 240, the first shuttle lane 250, and the second shuttle lane 260 together form a turning lane. Figure 2 The arrows indicate the direction in which the kiln car 210 moves on the turnaround track when the tunnel kiln is in operation.

[0048] The power unit is connected to the kiln car 210. The kiln car 210 moves along the rotary track under the drive of the power unit. The second track 240 is set outside the kiln body 100. When the kiln car 210 moves to the second track 240, the operator can take the dried battery pack 800 off the kiln car 210 and place a new battery pack 800 to be processed.

[0049] Understandably, multiple kiln cars 210 can be placed along the rotary track, and the kiln cars 210 can be continuously fed into the kiln body 100 without waiting for the previous battery pack 800 to complete the entire drying process before the next battery pack 800 is fed into the kiln body 100 for drying, which greatly improves the drying efficiency of the battery pack 800.

[0050] Since the first track 230 passes through the interior of the kiln body 100, it is made of insulating material to reduce heat loss in the heating zone 110 and the constant temperature zone 120. In some embodiments, the first track 230 is made of expanded clay concrete, that is, a material made of cement and porous ceramic particles, which can effectively prevent energy loss in the lower part of the kiln body 100 and reduce the power consumption per unit material processing.

[0051] In some embodiments, refer to Figure 2 The second track 240 is equipped with a discharge area 242 and a loading area 241. The loading area 241 is close to the first shuttle lane 250, and the discharge area 242 is located close to the second shuttle lane 260. Operators can place the battery pack 800 on the kiln car 210 in the loading area 241 and remove the dried battery pack 800 from the kiln car 210 in the discharge area 242.

[0052] In some embodiments, the power unit is a hydraulic jacking machine, which pushes the kiln car 210 to move on the first track 230 and the second track 240. In some embodiments, the tunnel kiln is equipped with a hydraulic station 220 to facilitate the operator's control of the hydraulic jacking machine.

[0053] In some embodiments, the first track 230 and the second track 240 are arranged in parallel to each other, which makes the overall layout of the tunnel kiln more reasonable and compact.

[0054] In some embodiments, refer to Figure 5 The kiln body 100 is provided with multiple movable chambers 140, each of which extends through both ends of the kiln body 100 along a first direction. The movable chambers 140 are used for the movement of the kiln car 210. In an embodiment with a first track 230, a second track 240, a first shuttle lane 250, and a second shuttle lane 260, the number of the first track 230, the second track 240, the first shuttle lane 250, and the second shuttle lane 260 corresponds to the number of movable chambers 140. With this configuration, the tunnel kiln can simultaneously dry battery packs 800 on multiple first tracks 230, improving drying efficiency.

[0055] In some embodiments, two moving cavities 140 are provided, and correspondingly, two tracks 230 and two tracks 240 are also provided, which can simultaneously dry two sets of battery packs 800 entering the kiln body 100.

[0056] In some embodiments, each movable cavity 140 is provided with a heating element on the side wall surface within the heating zone 110 and the constant temperature zone 120 to ensure effective heating within each movable cavity 140.

[0057] In some embodiments, the heating element is a heating rod, which uses electric heating to heat the heating zone 110 and the constant temperature zone 120. The outer layer of the heating rod is made of a corrosion-resistant material, such as PLS-SiC material with a purity greater than 99%, which can effectively slow down the corrosion of corrosive substances such as hydrofluoric acid, extend the service life of the heating rod, and ensure the stability of the process production.

[0058] In some embodiments, refer to Figure 1 and Figure 2 The kiln body 100 is provided with replacement chambers 700 at both ends along the first direction. The replacement chambers 700 are used to replace the gas at the inlet and outlet of the kiln body 100 to ensure that the gas concentration inside the kiln body 100 remains constant, thus ensuring the stability and effectiveness of the atmosphere inside the kiln body 100. The kiln car 210 enters the replacement chamber 700 located at the inlet end of the kiln body 100 through the first shuttle lane 250. After being depressurized, nitrogen gas is introduced to positive pressure, and then the car is sent into the kiln body 100 for drying under the action of the power components.

[0059] Understandably, one or more nitrogen pipes of the nitrogen system 500 are connected to two replacement chambers 700 respectively, and the nitrogen supply component introduces nitrogen through the nitrogen pipe box into the replacement chamber 700, which can realize the gas replacement in the replacement chamber 700.

[0060] In some embodiments, the tunnel kiln also includes temperature detection elements, such as temperature sensors, which can monitor the temperature inside the kiln body 100 to ensure that the temperature of the heating zone 110 rises stably to a preset value, the constant temperature zone 120 remains within a preset temperature range, and the cooling zone 130 cools down stably. When the temperature inside the kiln body 100 becomes abnormal, for example, if the temperature of the constant temperature zone 120 is lower than the preset temperature range, the operator can promptly inspect and repair the heating elements in the constant temperature zone 120.

[0061] In some embodiments, refer to Figure 2 The conveying system 200 includes a maintenance lane 270, which is located at the tail end of the kiln body 100, facilitating technicians to inspect and maintain the internal components of the tunnel kiln 100.

[0062] The process of drying lithium iron phosphate battery packs 800 using a tunnel kiln is as follows: First, the battery pack 800 is discharged. The top cover of the battery pack 800 is manually removed, and an external resistor is used to discharge the battery pack 800 until it reaches a safe voltage (the voltage of a single cell is less than 0.4V). Then, the safety valves of the individual cells inside the battery pack 800 are removed. After the battery pack 800 is discharged, it is hoisted from the loading area 241 onto the kiln car 210 by a crane. One battery pack 800 is placed on each kiln car 210. The kiln car 210 travels along the second track 240 and passes through the first transfer track 250 to reach the replacement chamber 700 at the entrance of the kiln body 100.

[0063] Kiln car 210 undergoes a 20-minute replacement period in replacement chamber 700. After the chamber is depressurized to negative pressure, nitrogen is introduced to create positive pressure. The kiln car 210 is then lowered by a hydraulic top-mounted machine and fed into kiln body 100 for drying. Kiln car 210 sequentially passes through heating zone 110, constant temperature zone 120, and cooling zone 130 in the first direction. Waste materials such as structural adhesive, electrolyte, binder, and separator decompose in heating zone 110 and constant temperature zone 120 and are discharged through exhaust system 400. The remaining material in battery pack 800 consists of recyclable battery powder, copper-aluminum foil, and aluminum casing. The exhaust fan 410 of exhaust system 400 drives the decomposed gas through exhaust pipe 420 to exhaust gas treatment component 450. Because heat tracing element 430 and insulation component 440 are arranged on the outside of exhaust pipe 420, the exhaust gas is always discharged in a gaseous state, effectively preventing condensation and improving the treatment efficiency, thereby increasing drying efficiency. The total drying time is 4 hours, of which the kiln car 210 moves for 1 hour in the heating zone 110, 1 hour in the constant temperature zone 120, and 2 hours in the cooling zone 130.

[0064] Subsequently, the kiln car 210 travels through the replacement chamber 700 at the kiln outlet of the kiln body 100 to the kiln tail, and then through the second shuttle lane 260 to the second track 240. The kiln car 210 continues to reach the unloading area 242 under the action of the hydraulic jack, where the battery pack 800 is unloaded via the hoisting device, completing the entire drying process. After unloading, the kiln car 210 continues along the second track 240 to the feeding area 241 to begin the feeding process, and repeats the aforementioned drying process.

[0065] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the embodiments described. Those skilled in the art can make various equivalent modifications or substitutions without departing from the spirit of the present invention. All such equivalent modifications or substitutions are included within the scope defined by the claims of this application.

Claims

1. A tunnel kiln characterized in that, include: The kiln body (100) is provided with a heating zone (110), a constant temperature zone (120) and a cooling zone (130) in sequence along the first direction. A heating system (600) is provided in the heating zone (110) and the constant temperature zone (120) for heating the heating zone (110) and the constant temperature zone (120); A cooling system (300) is provided in the cooling zone (130) for cooling the cooling zone (130). The exhaust system (400) includes an exhaust fan (410), an exhaust pipe (420), a heat tracing element (430), and a waste gas treatment component (450). The waste gas treatment component (450) is connected to the outlet end of the exhaust fan (410), the inlet end of the exhaust fan (410) is connected to the outlet end of the exhaust pipe (420), the inlet end of the exhaust pipe (420) is connected to the heating zone (110) and the constant temperature zone (120), and the heat tracing element (430) is disposed on the outer periphery of the exhaust pipe (420) and is used to heat the exhaust pipe (420).

2. Tunnel kiln according to claim 1, characterized in that The exhaust system (400) further includes an insulation component (440) which covers the outer periphery of the exhaust pipe (420), and the heat tracing element (430) is disposed between the insulation component (440) and the exhaust pipe (420).

3. The tunnel kiln according to claim 1, characterized in that The heating zone (110) and the constant temperature zone (120) are respectively connected to multiple exhaust pipes (420), and the exhaust pipes (420) are evenly distributed along the first direction.

4. The tunnel kiln according to claim 1, characterized in that, The exhaust system (400) also includes an exhaust pipe (460), the inlet end of the exhaust gas treatment component (450) and the outlet end of the exhaust fan (410) are connected through the exhaust pipe (460), and the heat tracing element (430) is provided on the outer periphery of the exhaust pipe (460).

5. The tunnel kiln according to claim 1, characterized in that, The tunnel kiln also includes: The nitrogen system (500) includes a nitrogen supply component and multiple nitrogen pipes. The inlet end of each nitrogen pipe is connected to the outlet end of the nitrogen supply component, and the outlet end of each nitrogen pipe is connected to the heating zone (110), the constant temperature zone (120), and the cooling zone (130).

6. The tunnel kiln according to claim 5, characterized in that The nitrogen system (500) also includes an oxygen detection element, which is located inside the kiln body (100) and is used to detect the oxygen content inside the kiln body (100).

7. The tunnel kiln of claim 1, wherein The cooling system (300) includes a cold water pipe and a water pump. The cold water pipe is laid on the top of the cooling zone (130), and the water pump is located on the outside of the kiln body (100). The outlet end and the inlet end of the cold water pipe extend out of the kiln body (100) respectively. The outlet end of the water pump is connected to the inlet end of the cold water pipe, and the inlet end of the water pump is connected to the outlet end of the cold water pipe.

8. The tunnel kiln of claim 1, wherein, The wall of the kiln body (100) includes a refractory layer (150), a heat insulation layer (160), and an impact-resistant layer (170), which are arranged sequentially from the inside to the outside.

9. The tunnel kiln of claim 1, wherein, The tunnel kiln also includes: The conveying system (200) includes a kiln car (210), a power unit, a first track (230), a second track (240), a first shuttle lane (250), and a second shuttle lane (260). The first track (230) passes through the kiln body (100) along a first direction. The second track (240) is located on the outside of the kiln body (100). The two ends of the first shuttle lane (250) are respectively connected to the entrance end of the first track (230) and the exit end of the second track (240). The two ends of the second shuttle lane (260) are respectively connected to the exit end of the first track (230) and the entrance end of the second track (240). The first track (230), the second shuttle lane (260), the second track (240), and the first shuttle lane (250) together form a turning lane. The power unit is driven by the kiln car (210) to drive the kiln car (210) to move along the turning lane.

10. The tunnel kiln of claim 1, wherein, The kiln body (100) is provided with a plurality of movable cavities (140), each of the movable cavities (140) passing through both ends of the kiln body (100) along a first direction.

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