Cold trap for lithium battery cell baking area vacuum system

Abstract

The utility model discloses a cold trap for a vacuum system in a lithium battery cell baking area in the technical field of lithium battery production, and aims to solve the problem of frost point condensation of a cold trap in the prior art. The heat exchanger comprises a bottom plate, a shell, a shell flange and a cold trap cover, the shell is welded to the bottom plate and the shell flange to form a closed space, the cold trap cover is fixed to the shell flange, a gas inlet, a gas outlet and a condensate outlet are formed in the shell, a liquid nitrogen inlet and a nitrogen outlet are formed in the cold trap cover, and the heat exchanger particularly comprises a spiral heat exchange pipe arranged in the shell; the spiral heat exchange tube is fixed at the bottom of the cold trap cover, one end is communicated with the liquid nitrogen inlet, and the other end is communicated with the nitrogen outlet. According to the utility model, the spiral heat exchange tube is arranged in the shell, so that the spiral heat exchange tube not only can stably capture NMP in the cavity of the drying oven, but also greatly increases the heat exchange area, is beneficial to gasification and reutilization of liquid nitrogen, and effectively prevents the vacuum pump from being corroded.

Description

Technical Field

[0001] The utility model relates to a cold trap for a vacuum system in a lithium battery core baking area, belonging to the technical field of lithium battery production equipment. Background Art

[0002] In the lithium battery cell baking section, in order to quickly bake the battery cells, the oven needs to be evacuated to 10~50 Pa. In the existing production line, an oil-filled rotary vacuum pump is generally used as a front-stage pump to pre-evacuate to about -96 kPa, and then the Roots pump is started to evacuate to the required vacuum degree of the oven.

[0003] With the continuous improvement of battery production technology, the NMP (N-methylpyrrolidone) content in the positive electrode sheets in the newly built production line seriously exceeded the standard. When the battery cells were baked in the oven, the vacuum pump pumped out a large amount of NMP and water vapor. NMP is a solvent. After dissolving in oil, the vacuum pump oil deteriorated, and the sealing ring and rotor were severely corroded. All these led to insufficient sealing of the oil rotor vacuum pump, thus affecting the vacuum degree of the vacuum system, causing great trouble to battery production.

[0004] In the prior art, liquid nitrogen cold traps are used as capture devices to capture NMP vapor and water vapor by condensation. Although the influence of NMP and water vapor can be eliminated from the source, the following problems may occur: 1. Frost will form during the operation of the cold trap, and the accumulation of frost points will increase the load-bearing capacity of the heat exchange tubes, affecting their stability. In severe cases, the heat exchange tubes may break; 2. If the cold trap is used for too long, impurities will inevitably remain, which is difficult to clean. Utility Model Content

[0005] The utility model aims to provide a cold trap for a vacuum system in a lithium battery core baking area, which can capture and recycle NMP and liquid nitrogen and reduce the failure rate.

[0006] In order to achieve the above purpose, the technical solution adopted by the utility model is as follows:

[0007] The utility model provides a cold trap for a vacuum system in a lithium battery cell baking area, comprising a bottom plate, a shell, a shell flange and a cold trap cover, wherein the shell is respectively welded to the bottom plate and the shell flange to form a closed space, the cold trap cover is fixed to the shell flange, an air inlet, an air outlet and a condensate outlet are arranged on the shell, a liquid nitrogen inlet and a nitrogen exhaust port are arranged on the cold trap cover, and further comprises a spiral heat exchange tube arranged inside the shell;

[0008] One end of the spiral heat exchange tube is connected to the liquid nitrogen inlet, and the other end is connected to the nitrogen exhaust port.

[0009] Preferably, the spiral heat exchange tube is fixed in the cold trap through a fixed end and a tube rack;

[0010] The fixed ends are evenly arranged on the cold trap cover along the spiral diameter of the spiral heat exchange tube;

[0011] One end of the pipe rack is fixedly connected to the fixed end;

[0012] The tube rack is provided with support holes, and the support holes are arranged equidistantly according to the longitudinal spiral tube pitch of the spiral heat exchange tube;

[0013] The spiral heat exchange tube is placed on the supporting hole.

[0014] Preferably, the spiral heat exchange tube is an odd-numbered spiral heat exchange tube.

[0015] The odd-numbered spiral heat exchange tubes are arranged downward from the point connected to the liquid nitrogen inlet along the center line of the shell to the bottom of the shell, and then spiral upward for an odd number of times according to a set diameter and are connected to the nitrogen exhaust port.

[0016] Preferably, the set diameter is 300mm~350mm.

[0017] Preferably, the spiral heat exchange tube is an even-numbered spiral heat exchange tube.

[0018] The even-numbered spiral heat exchange tubes start from the connection with the liquid nitrogen inlet, spiral downward for an even number of times according to the set diameter one, and then spiral upward for an even number of times according to the set diameter two, and are connected with the nitrogen exhaust port;

[0019] The tube rack is provided with two groups, inner and outer, wherein the inner tube rack is used to support the spiral heat exchange tube spiraling downward, and the outer tube rack is used to support the spiral heat exchange tube spiraling upward.

[0020] Preferably, the set diameter one is 200 mm to 250 mm, and the set diameter two is 400 mm to 450 mm.

[0021] Preferably, a baffle is provided inside the housing;

[0022] The baffle is L-shaped and is fixed above the air inlet.

[0023] Preferably, the cold trap further comprises a spray port;

[0024] The spray port is arranged at the center position of the top of the cold trap cover or at the side of the cold trap shell; the spray port is used to spray spray liquid to perform heat exchange and defrost the frost points in the spiral heat exchange tube.

[0025] Preferably, the cold trap further comprises a vent with a stop valve;

[0026] The vent with the stop valve is arranged on the top of the cold trap cover; the vent with the stop valve is opened during defrosting to introduce air to exchange heat with the frost point in the spiral heat exchange tube for defrosting.

[0027] Preferably, the cold trap further comprises a heated air inlet;

[0028] The heated air inlet is arranged on the top of the cold trap cover; the heated air inlet is used to introduce heated air to exchange heat with the frost point in the spiral heat exchange tube for defrosting.

[0029] Preferably, the cold trap further comprises a hanging column;

[0030] The hanging column is arranged on the cold trap cover.

[0031] Preferably, the bottom plate is an elliptical structure or a conical structure.

[0032] Compared with the prior art, the utility model has the following beneficial effects:

[0033] 1. The utility model provides a cold trap for a vacuum system in a lithium battery cell baking area. By arranging a spiral heat exchange tube inside the shell, the spiral heat exchange tube can not only stably capture NMP in the oven cavity, but also greatly increase the heat exchange area, which is beneficial to the gasification and reuse of liquid nitrogen and effectively prevents corrosion of the vacuum pump.

[0034] 2. The cold trap provided by the utility model for the vacuum system of the lithium battery cell baking area also realizes rapid defrosting, reduces the accumulation of frost points, makes the spiral heat exchange tube less prone to brittle cracking, and reduces the failure rate.

[0035] 3. The cold trap device provided by the utility model can be disassembled for maintenance and is easy to clean. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 This is a diagram of a cold trap device when top spray defrosting is used in Example 1 of the utility model;

[0037] Figure 2 This is a diagram of a cold trap device when the shell side spray defrosting is adopted in Example 2 of the utility model;

[0038] Figure 3 This is a diagram of a cold trap device when air defrosting is used in Example 3 of the utility model;

[0039] Figure 4 This is a diagram of a cold trap device when heated air is used to accelerate defrosting in Example 4 of the utility model;

[0040] Figure 5 This is a diagram showing the connection between the fixed end and the pipe rack in one embodiment of the utility model;

[0041] Figure 6 This is a diagram of an odd-numbered spiral heat exchange tube in one embodiment of the utility model;

[0042] Figure 7 This is a diagram of an even-numbered spiral heat exchange tube in one embodiment of the utility model;

[0043] Figure 8 This is a front view of a support for an odd-numbered spiral heat exchange tube rack in one embodiment of the utility model;

[0044] Fig. 9 This is a bottom view of a support for an odd-numbered spiral heat exchange tube rack in one embodiment of the utility model;

[0045] Fig.10 This is a front view of a support for an even-numbered spiral heat exchange tube rack in one embodiment of the utility model;

[0046] Fig.11 This is a bottom view of a support for an even-numbered spiral heat exchange tube rack in one embodiment of the utility model. DETAILED DESCRIPTION

[0047] The specific implementation of the utility model will be further described in detail below in conjunction with the accompanying drawings and embodiments. The embodiments described below with reference to the accompanying drawings are illustrative and intended to be used to explain the utility model, and should not be understood as limiting the utility model.

[0048] In the description of the present invention, it should be noted that the terms "upper", "lower", "front", "rear", "end", "bottom", "side", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or component referred to must have a specific orientation. Therefore, they cannot be understood as limitations on the present invention.

[0049] In the present invention, unless otherwise specified or limited, the terms "connection" and "installation" should be understood in a broad sense, for example, it can be a fixed connection, a direct connection, or a connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0050] Secondly, the term "one embodiment" or "embodiment" as used in the present invention refers to a specific feature, structure or characteristic that may be included in at least one implementation of the present invention. The term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive with other embodiments.

[0051] The following embodiments of the present invention are described in further detail in conjunction with the accompanying drawings. The following embodiments are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0052] Example 1, reference Figure 1 , which is the first embodiment of the utility model, and provides a cold trap for a vacuum system in a lithium battery cell baking area, comprising a bottom plate 1, a shell 4, a shell flange 6, a cold trap cover 7, an air inlet 3, an air outlet 12, a condensate outlet 15, a liquid nitrogen inlet 8, a spray port 9, a hanging column 10, a nitrogen exhaust port 11, and a spiral heat exchange tube 13, a fixed end 5 and a pipe rack 14 arranged inside the shell 4.

[0053] Specifically, the shell 4 is welded to the bottom plate 1 and the shell flange 6 respectively, the cold trap cover 7 is fixedly connected to the shell flange 6 by bolts, and the hanging column 10 is arranged on the cold trap cover 7 .

[0054] See also Figure 5 A fixed end 5 is provided at the bottom of the cold trap cover 7 , and the fixed end 5 is fixedly connected to a pipe rack 14 by bolts. The pipe rack 14 is used to support the spiral heat exchange tube 13 .

[0055] One end of the spiral heat exchange tube 13 is connected to the liquid nitrogen inlet 8, and the other end is connected to the nitrogen exhaust port 11. The spiral heat exchange tube can stably capture the NMP in the oven cavity, is not easy to crack, has a low failure rate, and greatly increases the heat exchange area, which is conducive to the gasification of liquid nitrogen in the spiral heat exchange tube.

[0056] It should be noted that the fixed ends 5 are evenly arranged on the cold trap cover 7 along the spiral tube diameter of the spiral heat exchange tube 13 , and the number of the fixed ends 5 is determined by the stress conditions.

[0057] The air inlet 3 , the air outlet 12 and the condensate outlet 15 are all arranged outside the shell 4 , the liquid nitrogen inlet 8 and the nitrogen exhaust port 11 are arranged on the top of the cold trap cover 7 , and the spray port 9 is arranged at the center of the top of the cold trap cover 7 .

[0058] Preferably, a baffle 2 is provided inside the shell 4. The baffle 2 is composed of two rectangular flat steels and has an L-shaped cross-section. It is fixed 100 mm above the air inlet. It can prevent the incoming air from impacting the spiral heat exchange tube and control the incoming air to exchange heat in a stable and sequential manner from the bottom of the spiral heat exchange tube upward.

[0059] Preferably, the bottom plate 1 may be an elliptical structure or a conical structure.

[0060] During the use of this embodiment 1, before vacuuming, liquid nitrogen first enters from the liquid nitrogen inlet 8, and then the oven gas enters from the air inlet 3. Under the action of the baffle 2, the spiral heat exchange tube 13 can be protected from the impact of the oven gas, and the oven gas can also be gradually and stably heat exchanged from the bottom of the spiral heat exchange tube 13 upward, condensed into frost on the spiral heat exchange tube 13, and the non-condensable gas is discharged from the exhaust port 12. The spiral heat exchange tube 13 is supported by the pipe rack 14, which not only enables the spiral heat exchange tube 13 to stably capture the NMP in the oven cavity, is not easy to crack, and has a low failure rate, but also greatly increases the heat exchange area, which is conducive to the gasification of liquid nitrogen in the spiral heat exchange tube 13. The gasified nitrogen is discharged from the nitrogen exhaust port 11 and fed to the workshop for reuse. When the vacuuming is stopped, the spray liquid enters from the spray port 9 and is evenly sprayed in the spiral heat exchange tube 13 for defrosting. After the NMP and water vapor frost point in the spiral heat exchange tube 13 melt, they are discharged and recycled from the condensate discharge port 15.

[0061] It should be noted that after the cold trap device provided in this embodiment has been working for a period of time, impurities will accumulate in the shell 4, which is difficult to clean or needs maintenance. The cold trap cover 7 is opened and moved away by the hanging column 10 for cleaning and maintenance.

[0062] Example 2, reference Figure 2 , which is the second embodiment of the utility model, and provides another cold trap for a vacuum system in a lithium battery cell baking area, including a bottom plate 1, a shell 4, a shell flange 6, a cold trap cover 7, an air inlet 3, an air outlet 12, a condensate outlet 15, a liquid nitrogen inlet 8, a spray port 9, a hanging column 10, a nitrogen exhaust port 11, and a spiral heat exchange tube 13, a fixed end 5 and a pipe rack 14 arranged inside the shell 4.

[0063] Specifically, the shell 4 is welded to the bottom plate 1 and the shell flange 6 respectively; the cold trap cover 7 is fixedly connected to the shell flange 6 by bolts, and the hanging column 10 is arranged on the cold trap cover 7 .

[0064] See also Figure 5 A fixed end 5 is provided at the bottom of the cold trap cover 7, and the fixed end 5 is fixedly connected to a pipe rack 14 by bolts, and the pipe rack 14 is used to support the spiral heat exchange tube 13. One end of the spiral heat exchange tube 13 is connected to the liquid nitrogen inlet 8, and the other end is connected to the nitrogen exhaust port 11.

[0065] The air inlet 3 , the air outlet 12 and the condensate outlet 15 are arranged outside the shell 4 , the liquid nitrogen inlet 8 and the nitrogen exhaust port 11 are arranged on the top of the cold trap cover 7 , and the spray port 9 is placed on the side of the cold trap shell 4 .

[0066] Preferably, a baffle 2 is disposed inside the shell 4. The baffle 2 is composed of two rectangular flat steels, has an L-shaped cross-section, and is fixed 100 mm above the air inlet.

[0067] During the use of this embodiment 2, before vacuuming, liquid nitrogen first enters from the liquid nitrogen inlet 8, and then the oven gas enters from the air inlet 3. Under the action of the baffle 2, the spiral heat exchange tube 13 can be protected from the impact of the oven gas, and the oven gas can also be heat-exchanged from the bottom of the spiral heat exchange tube 13 upward in a stable manner, condensed into frost on the spiral heat exchange tube 13, and the non-condensable gas is discharged from the exhaust port 12. The spiral heat exchange tube 13 is supported by the pipe rack 14, which not only enables the spiral heat exchange tube 13 to stably capture the NMP in the oven cavity, is not easy to crack, and has a low failure rate, but also greatly increases the heat exchange area, which is conducive to the gasification of liquid nitrogen in the spiral heat exchange tube 13. The gasified nitrogen is discharged from the nitrogen exhaust port 11 and fed to the workshop for reuse. When the vacuuming is stopped, the spray liquid enters from the spray port 9 and is evenly sprayed in the spiral heat exchange tube 13 for defrosting. After the NMP and water vapor frost point in the spiral heat exchange tube 13 melt, they are discharged and recycled from the condensate discharge port 15.

[0068] It should be noted that after the cold trap device provided in the present embodiment 2 has been in operation for a period of time, impurities will accumulate in the shell 4, which is difficult to clean or needs maintenance. The cold trap cover 7 is opened and moved away by the hanging column 10 for cleaning and maintenance.

[0069] Example 3, reference Figure 3 , which is the third embodiment of the utility model, and provides another cold trap for a vacuum system in a lithium battery cell baking area, comprising a bottom plate 1, a shell 4, a shell flange 6, a cold trap cover 7, an air inlet 3, an air outlet 12, a condensate outlet 15, a liquid nitrogen inlet 8, a hanging column 10, a nitrogen exhaust port 11, and a spiral heat exchange tube 13, a fixed end 5 and a pipe rack 14 disposed inside the shell 4, and also comprising a vent 16 with a stop valve.

[0070] Specifically, the shell 4 is welded to the bottom plate 1 and the shell flange 6 respectively; the cold trap cover 7 is fixedly connected to the shell flange 6 by bolts, and the hanging column 10 is arranged on the cold trap cover 7 .

[0071] A fixed end 5 is provided at the bottom of the cold trap cover 7 , and the fixed end 5 is fixedly connected to a pipe rack 14 by bolts. The pipe rack 14 is used to support the spiral heat exchange tube 13 .

[0072] The air inlet 3, the air outlet 12 and the condensate outlet 15 are arranged outside the shell 4, and the liquid nitrogen inlet 8 and the nitrogen exhaust port 11 are arranged on the top of the cold trap cover 7. One end of the spiral heat exchange tube 13 is connected to the liquid nitrogen inlet 8, and the other end is connected to the nitrogen exhaust port 11.

[0073] In this embodiment, a vent 16 with a stop valve is arranged on the top of the cold trap cover 7 .

[0074] Preferably, a baffle 2 is disposed inside the shell 4. The baffle 2 is composed of two rectangular flat steels, has an L-shaped cross-section, and is fixed 100 mm above the air inlet.

[0075] During the use of this embodiment 3, before vacuuming, liquid nitrogen first enters from the liquid nitrogen inlet 8, and then the oven gas enters from the air inlet 3. Under the action of the baffle 2, the spiral heat exchange tube 13 can be protected from the impact of the oven gas, and the oven gas can also be heat-exchanged upward from the bottom of the spiral heat exchange tube 13 in a stable and orderly manner, condensing into frost on the spiral heat exchange tube 13, and the non-condensable gas is discharged from the exhaust port 12. The spiral heat exchange tube 13 is supported by the tube rack 14, which not only enables the spiral heat exchange tube 13 to stably capture the NMP in the oven cavity, is not easy to crack, and has a low failure rate, but also greatly increases the heat exchange area, which is conducive to the gasification of liquid nitrogen in the spiral heat exchange tube 13. The gasified nitrogen is discharged from the nitrogen exhaust port 11 to the workshop for reuse. When the vacuum pumping stops, the vent 16 with the stop valve is opened. Under the action of the induced draft fan, air enters from the vent 16 with the stop valve and exchanges heat with the frost point in the spiral heat exchange tube 13. After the NMP and water vapor frost point melt, they are discharged from the condensate discharge port 15 for recovery.

[0076] It should be noted that after the cold trap device provided in the present embodiment 3 has been working for a period of time, impurities will accumulate in the shell 4, which is difficult to clean or needs maintenance. The cold trap cover 7 is opened and the cold trap cover is moved away by the hanging column 10 for cleaning and maintenance.

[0077] Example 4, reference Figure 4 , which is the fourth embodiment of the utility model, and this embodiment provides another cold trap for a vacuum system in a lithium battery cell baking area, including a bottom plate 1, a shell 4, a shell flange 6, a cold trap cover 7, an air inlet 3, an air outlet 12, a condensate outlet 15, a liquid nitrogen inlet 8, a hanging column 10, a nitrogen exhaust port 11, and a spiral heat exchange tube 13, a fixed end 5 and a pipe rack 14 arranged in the shell, and also includes a heated air inlet 17.

[0078] Specifically, the shell 4 is welded to the bottom plate 1 and the shell flange 6 respectively; the cold trap cover 7 is fixedly connected to the shell flange 6 by bolts, and the hanging column 10 is arranged on the cold trap cover 7 .

[0079] A fixed end 5 is provided at the bottom of the cold trap cover 7, and the fixed end 5 is fixedly connected to a pipe rack 14 by bolts. The pipe rack 14 is used to support a spiral heat exchange tube 13, one end of the spiral heat exchange tube 13 is connected to a liquid nitrogen inlet 8, and the other end is connected to a nitrogen exhaust port 11.

[0080] The air inlet 3 , the air outlet 12 and the condensate outlet 15 are arranged outside the shell 4 , and the liquid nitrogen inlet 8 and the nitrogen exhaust port 11 are arranged on the top of the cold trap cover 7 .

[0081] In this embodiment, the heating air inlet 17 is arranged on the top of the cold trap cover 7 .

[0082] Preferably, a baffle 2 is disposed inside the shell 4. The baffle 2 is composed of two rectangular flat steels, has an L-shaped cross-section, and is fixed 100 mm above the air inlet.

[0083] During the use of this embodiment 4, before vacuuming, liquid nitrogen first enters from the liquid nitrogen inlet 8, and then the oven gas enters from the air inlet 3. Under the action of the baffle 2, the spiral heat exchange tube 13 can be protected from the impact of the oven gas, and the oven gas can also be heat-exchanged from the bottom of the spiral heat exchange tube 13 upward in a stable manner, condensed into frost on the spiral heat exchange tube 13, and the non-condensable gas is discharged from the exhaust port 12. The spiral heat exchange tube 13 is supported by the pipe rack 14, which not only enables the spiral heat exchange tube 13 to stably capture the NMP in the oven cavity, is not easy to crack, and has a low failure rate, but also greatly increases the heat exchange area, which is conducive to the gasification of liquid nitrogen in the spiral heat exchange tube 13. The gasified nitrogen is discharged from the nitrogen exhaust port 11 and fed to the workshop for reuse. When the vacuuming stops, the heated air passes through the heated air inlet 17, and under the action of the induced draft fan, it quickly exchanges heat with the frost point in the spiral heat exchange tube 13. After the NMP and water vapor frost point melt, they are discharged and recycled from the condensate discharge port 15.

[0084] It should be noted that after the cold trap device provided in the present embodiment 4 has been in operation for a period of time, impurities will accumulate in the shell 4, which is difficult to clean or needs maintenance. The cold trap cover 7 is opened and moved away by the hanging column 10 for cleaning and maintenance.

[0085] Further, in one embodiment, the spiral heat exchange tube 13 is an odd-numbered spiral heat exchange tube 1301, see Figure 6 The odd-numbered spiral heat exchange tube 1301, i.e., the heat exchange tube connected to the liquid nitrogen inlet 8, is first arranged downward from the center line of the shell 4 to the bottom of the shell 4, and then spirals an odd number of times from bottom to top with a certain diameter and is connected to the nitrogen exhaust port 11.

[0086] See also Fig. 9 In this embodiment, the fixed end 5 is 4 No. 10 channel steels with a length of 100 mm, which are evenly welded on the cold trap cover 7 along the spiral diameter of the odd-numbered spiral heat exchange tubes, and the fixed end 5 is fixedly connected to the pipe rack 14 along the center line with bolts. Figure 8 Support holes are provided on the tube rack 14, and the support holes are evenly spaced along the center line according to the longitudinal spiral tube spacing of the spiral heat exchange tube 13, so as to stably support the odd-numbered spiral heat exchange tubes 1301, so that the odd-numbered spiral heat exchange tubes 1301 can stably capture the NMP in the oven cavity, are not prone to brittle cracking, have a low failure rate, and greatly increase the heat exchange area.

[0087] In this embodiment, the spiral diameter of the odd-numbered spiral heat exchange tube is 300-350 mm. During use, the heat exchange tube at one end of the spiral heat exchange tube 13 connected to the liquid nitrogen inlet 8 is first arranged downward from the center line of the shell 4 to the bottom of the shell 4, and then spiraled upward with a diameter of 300-350 mm to be connected to the nitrogen exhaust port 11.

[0088] It should be noted that the odd number of turns of the spiral heat exchange tube 13 depends on the actual heat exchange situation.

[0089] Further, in another embodiment, the spiral heat exchange tube 13 is an even-numbered spiral heat exchange tube 1302, see Figure 7 The even-numbered spiral heat exchange tube 1302, i.e. the heat exchange tube connected to the liquid nitrogen inlet 8, spirals downward and upward for an even number of times with a certain diameter and then connects to the nitrogen exhaust port 11.

[0090] Specifically, when the spiral heat exchange tube 13 is an even-numbered spiral heat exchange tube 1302, the heat exchange tube connected to the liquid nitrogen inlet 8 first spirals downward with a diameter of 200-250 mm, then spirals upward with a diameter of 400-450 mm and is connected to the nitrogen exhaust port 11.

[0091] See also Fig.11 In this embodiment, the fixed ends 5 are 8 No. 10 channel steels with a length of 100 mm, which are evenly welded on the cold trap cover 7 with diameters of 200-250 mm and 400-450 mm, respectively. Four fixed ends 5 are set on each diameter, and the fixed ends 5 are fixedly connected to the pipe rack 14 along the center line with bolts.

[0092] See also Fig.10 The tube rack is provided with support holes, and the support holes are evenly spaced along the center line according to the longitudinal spiral tube spacing of the spiral heat exchange tube 13. The internal tube rack supports the internal even-numbered spiral heat exchange tubes, and the external tube rack supports the external even-numbered spiral heat exchange tubes, so that the even-numbered spiral heat exchange tubes 1302 can stably capture the NMP in the oven cavity, are not easy to crack, have a low failure rate, and greatly increase the heat exchange area.

[0093] It should be noted that the even number of turns of the spiral heat exchange tube 13 is determined by the actual heat exchange situation.

[0094] Importantly, it should be noted that the construction and arrangement of the present application shown in a number of different exemplary embodiments are only exemplary. Although only a few embodiments are described in detail in this disclosure, it should be readily understood by those who refer to this disclosure that many modifications are possible (e.g., the size, scale, structure, shape and proportion of various elements, and parameter values ​​(e.g., temperature, pressure, etc.), mounting arrangements, use of materials, color, directional changes, etc.) without substantially departing from the novel teachings and advantages of the subject matter described in the application. For example, an element shown as integrally formed may be composed of multiple parts or elements, the position of the element may be inverted or otherwise changed, and the nature or number or position of the discrete element may be altered or changed. Therefore, all such modifications are intended to be included within the scope of the present invention. The order or sequence of any process or method steps may be changed or reordered according to alternative embodiments. In the claims, any "device plus function" clause is intended to cover the structure that performs the function described in the present utility model, and is not only structurally equivalent but also an equivalent structure. Without departing from the scope of the present invention, other substitutions, modifications, changes and omissions may be made in the design, operating conditions and arrangement of the exemplary embodiments. Therefore, the present invention is not limited to a specific embodiment, but extends to various modifications that still fall within the scope of the appended claims.

[0095] Additionally, in order to provide a concise description of example embodiments, all features of an actual embodiment may not be described (ie, those features that are not relevant to the best mode presently contemplated for carrying out the invention or those that are not relevant to implementing the invention).

[0096] It will be appreciated that in the development of any actual implementation, as in any engineering or design project, numerous implementation-specific decisions may be made. Such a development effort may be complex and time-consuming, but will be a routine task of design, fabrication, and production for those of ordinary skill having the benefit of this disclosure without undue experimentation.

[0097] It should be noted that the above embodiments are only used to illustrate the technical solution of the utility model rather than to limit it. Although the utility model has been described in detail with reference to the preferred embodiments, ordinary technicians in the field should understand that the technical solution of the utility model can be modified or replaced by equivalents without departing from the spirit and scope of the technical solution of the utility model, which should be included in the scope of the claims of the utility model.

Claims

1. A cold trap for a vacuum system in a lithium battery cell baking area, comprising a bottom plate, a shell, a shell flange and a cold trap cover, wherein the shell is respectively welded to the bottom plate and the shell flange to form a closed space, the cold trap cover is fixed to the shell flange, the shell is provided with an air inlet, an air outlet and a condensate outlet, and the cold trap cover is provided with a liquid nitrogen inlet and a nitrogen exhaust port, characterized in that: Also included is a spiral heat exchange tube disposed inside the shell; One end of the spiral heat exchange tube is communicated with the liquid nitrogen inlet, and the other end is communicated with the nitrogen exhaust port.

2. A cold trap for a vacuum system in a lithium battery cell baking area according to claim 1, characterized in that: The spiral heat exchange tube is fixed in the cold trap through a fixed end and a tube rack; The fixed ends are evenly arranged on the cold trap cover along the spiral diameter of the spiral heat exchange tube; One end of the pipe rack is fixedly connected to the fixed end; The tube rack is provided with support holes, and the support holes are arranged equidistantly according to the longitudinal spiral tube pitch of the spiral heat exchange tube; The spiral heat exchange tube is placed on the supporting hole.

3. A cold trap for a vacuum system in a lithium battery cell baking area according to claim 2, characterized in that: The spiral heat exchange tube is an odd-numbered spiral heat exchange tube. The odd-numbered spiral heat exchange tubes are arranged downward from the point connected to the liquid nitrogen inlet along the center line of the shell to the bottom of the shell, and then spiral upward for an odd number of times according to a set diameter and are connected to the nitrogen exhaust port.

4. A cold trap for a vacuum system in a lithium battery cell baking area according to claim 3, characterized in that: The set diameter is 300mm~350mm.

5. A cold trap for a vacuum system in a lithium battery cell baking area according to claim 2, characterized in that: The spiral heat exchange tube is an even-numbered spiral heat exchange tube. The even-numbered spiral heat exchange tubes start from the connection with the liquid nitrogen inlet, spiral downward for an even number of times according to the set diameter one, and then spiral upward for an even number of times according to the set diameter two, and are connected with the nitrogen exhaust port; The tube rack is provided with two groups, inner and outer, wherein the inner tube rack is used to support the spiral heat exchange tube spiraling downward, and the outer tube rack is used to support the spiral heat exchange tube spiraling upward.

6. A cold trap for a vacuum system in a lithium battery cell baking area according to claim 5, characterized in that: The set diameter one is 200mm~250mm, and the set diameter two is 400mm~450mm.

7. A cold trap for a vacuum system in a lithium battery cell baking area according to claim 1, characterized in that: A baffle is arranged inside the shell; The baffle is L-shaped and is fixed above the air inlet.

8. A cold trap for a vacuum system in a lithium battery cell baking area according to claim 1, characterized in that: The cold trap also includes a spray port; The spray port is arranged at the center position of the top of the cold trap cover or at the side of the cold trap shell; the spray port is used to spray spray liquid to perform heat exchange and defrost the frost points in the spiral heat exchange tube.

9. A cold trap for a vacuum system in a lithium battery cell baking area according to claim 1, characterized in that: The cold trap also includes a vent with a stop valve; The vent with the stop valve is arranged on the top of the cold trap cover; the vent with the stop valve is opened during defrosting to introduce air to exchange heat with the frost point in the spiral heat exchange tube for defrosting.

10. The cold trap for a vacuum system in a lithium battery cell baking area according to claim 1, characterized in that: The cold trap also includes a heated air inlet; The heated air inlet is arranged on the top of the cold trap cover; the heated air inlet is used to introduce heated air to exchange heat with the frost point in the spiral heat exchange tube for defrosting.

11. A cold trap for a vacuum system in a lithium battery cell baking area according to claim 1, characterized in that: The cold trap also includes a hanging column; The hanging column is arranged on the cold trap cover.

12. A cold trap for a vacuum system in a lithium battery cell baking area according to claim 1, characterized in that: The bottom plate is an elliptical structure or a conical structure.

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