A device for recovering heat energy and NMP during positive electrode coating in lithium battery production.

Abstract

This invention relates to the field of lithium battery production technology, specifically to a device for recovering heat energy and NMP during positive electrode coating in lithium battery production. The invention includes an oven mechanism, a condensation and reheating mechanism, and a recovery mechanism. The condensation and reheating mechanism comprises an inner tube with coaxially spaced condensing fins and an outer tube with reheating fins. A semiconductor refrigeration chip is embedded in the inner tube, with the cooling end facing inward and the heating end facing outward, forming a condensation chamber within the inner cavity of the inner tube. A heating chamber is formed at the interval between the inner and outer tubes. A guiding air duct connects the condensation chamber and the heating chamber. In this invention, the heat energy generated by the condensation components during condensation reheats the condensed gas and recirculates it back into the oven. This effectively prevents ambient temperature air from entering the oven and affecting the uniformity of battery drying, and also improves energy utilization.

Description

Technical Field

[0001] This invention relates to the field of lithium battery production technology, specifically to a device for recovering heat energy and NMP during positive electrode coating in lithium battery production. Background Technology

[0002] NMP, also known as N-methylpyrrolidone, is a colorless, transparent, oily liquid with low volatility and excellent thermal and chemical stability. It evaporates with water vapor. Large quantities of NMP solvent are required in lithium-ion battery manufacturing production lines. However, NMP solution is expensive, accounting for a significant portion of battery manufacturing costs. During the coating process in battery production, NMP turns into a gaseous phase and is discharged with the drying gas. Discarding it immediately after use is neither economical nor environmentally friendly, and therefore, it must be recycled.

[0003] For example, Chinese patent CN208055235U discloses a device for recovering NMP solution from an oven. This cited patent uses a centrifugal blower to sequentially introduce a mixed gas from the oven into a heat exchanger and two sets of cooling coils before discharging it into the atmosphere. As the mixed gas passes through the heat exchanger and cooling coils, the NMP and water vapor in the mixed gas are condensed into liquid by the heat exchanger and cooling coils, and then flow to an NMP recovery tank to recover the NMP solution. The cited patent's method of directly discharging the condensed hot air from the oven into the atmosphere using a centrifugal blower obviously results in energy loss from the oven. Simultaneously, the oven needs to draw in ambient air, leading to uneven heat distribution and affecting the uniformity of battery drying. Furthermore, the heat generated by the heat exchanger during condensation cannot be recovered and utilized, resulting in energy waste. Therefore, this issue urgently needs to be addressed. Summary of the Invention

[0004] In order to avoid and overcome the technical problems existing in the prior art, the present invention provides a thermal energy and NMP recovery device for positive electrode coating in lithium battery production. The device relies on the heat energy generated by the condensation component during condensation to reheat the condensed gas and then recirculate it into the oven. This can effectively prevent room temperature air from entering the oven and affecting the uniformity of battery drying, and also improve the energy utilization rate.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] A device for recovering heat energy and NMP during positive electrode coating in lithium battery production includes an oven mechanism, a condensation and reheating mechanism, and a recovery mechanism. The condensation and reheating mechanism includes an inner tube with coaxially spaced condensation fins and an outer tube with reheating fins. A semiconductor cooling chip is embedded in the inner tube with the cooling end facing inward and the heating end facing outward, forming a condensation chamber within the inner cavity of the inner tube. A heating chamber is formed at the interval between the inner tube and the outer tube. A guide air duct connects the condensation chamber and the heating chamber. The mixed gas discharged from the oven mechanism passes through the air inlet of the inner tube, sequentially through the condensation chamber, the guide air duct, and the heating chamber, and then flows back to the oven mechanism through the exhaust port of the outer tube. The input end of the recovery mechanism is connected to the drain end of the inner tube.

[0007] As a further aspect of the present invention: the inner tube of the condensing fin has a structure with one end open and the other end sealed, the outer tube of the reheating fin has a structure with both ends sealed, there is a gap between the open end of the inner tube of the condensing fin and the end of the outer tube of the reheating fin, the gap constitutes a guide air duct, and the air inlet and exhaust outlet are respectively connected to the exhaust structure and air inlet structure of the oven mechanism.

[0008] As a further aspect of the present invention: the semiconductor cooling chips are several groups distributed along the axial direction of the inner tube of the condenser fins, and each group of semiconductor cooling chips is a number of chips evenly distributed circumferentially on the outer periphery of the inner tube of the condenser fins.

[0009] As a further embodiment of the present invention: the oven mechanism includes a positive electrode coating oven, the air inlet is located on the inner tube of the condenser fins away from the air duct, the exhaust port is located on the outer tube of the reheat fins away from the air duct, the positive electrode coating oven is connected to the air inlet through an exhaust pipe, and the positive electrode coating oven is connected to the exhaust port through a return air pipe.

[0010] As a further embodiment of the present invention: a return air fan is installed on the return air duct, and an exhaust fan is installed on the exhaust air duct.

[0011] As a further embodiment of the present invention: the recycling mechanism includes an NMP recycling tank, which is connected to the drain end of the inner tube of the condenser fins through a recycling pipe, and the output end of the NMP recycling tank is used to feed the slurry.

[0012] As a further embodiment of the present invention, an NMP recovery pump is installed on the recovery pipeline.

[0013] As a further aspect of the present invention: the semiconductor cooling chip is powered by a power supply mechanism, which includes a solar panel and a municipal power grid.

[0014] As a further embodiment of the present invention: the output end of the solar panel is connected to an energy storage container and a numerical control matching device, the output end of the energy storage container is electrically connected to the numerical control matching device, and the numerical control matching device is electrically connected to each semiconductor cooling chip through a circuit distribution box.

[0015] As a further aspect of the present invention, the energy storage container is also electrically connected to the output end of the municipal power grid.

[0016] Compared with the prior art, the beneficial effects of the present invention are:

[0017] 1. The condensation and reheating mechanism adopts a coaxial arrangement of the inner tube of the condensation fins and the outer tube of the reheating fins. A semiconductor cooling chip is embedded in the inner tube of the condensation fins, with the cooling end of the semiconductor cooling chip facing inward and the heating end facing outward. This makes the inner cavity of the inner tube of the condensation fins a condensation chamber, and the space between the inner tube of the condensation fins and the outer tube of the reheating fins a heating chamber. After the airflow from the oven mechanism enters the condensation chamber, the NMP in the external airflow condenses into an NMP solution. The NMP solution is then introduced into the recovery mechanism, while the gas continues to be introduced into the heating chamber through the guide air duct for reheating, and finally flows back to the oven mechanism. In the above structure, the condensation and reheating mechanism realizes the condensation and recovery of the NMP solution in a relatively compact space, and also realizes the reheating of the condensed gas through the recovery of heat energy, preventing room temperature air from entering the oven mechanism and affecting the uniformity of battery drying.

[0018] 2. The outer tube of the reheat fin adopts a two-end sealed structure, which effectively reduces heat loss. The inner tube of the condenser fin adopts a one-end open and one-end sealed structure, which also effectively reduces the loss of cold air and ensures the effect of heating and condensing the airflow.

[0019] 3. The semiconductor cooling chips are arranged in several groups along the axial direction of the inner tube of the condenser fins. Each group of semiconductor cooling chips is provided with several chips evenly distributed on the outer periphery of the inner tube of the condenser fins, thereby ensuring the uniformity of heating and cooling in the heating chamber and the condensing chamber.

[0020] 4. The air inlet is located on the inner tube of the condenser fins, away from the airflow duct, and the exhaust port is located on the outer tube of the reheat fins, away from the airflow duct. This ensures the flow path of the gas after entering the condenser and heating chambers as much as possible, thereby further ensuring the effect of gas condensation and reheating after condensation.

[0021] 5. The installation of exhaust and return air fans effectively ensures the efficiency of gas circulation in the positive electrode coating oven, thereby improving the drying efficiency of lithium batteries in the negative electrode coating oven.

[0022] 6. The NMP solution is recovered into the recovery tank by connecting the recovery pipe to the drain end of the inner tube of the condenser fin, and then sent into the mixing slurry through the output end of the recovery tank to complete the recycling of the NMP solution.

[0023] 7. The NMP recovery pump provides the kinetic energy for recovering the NMP solution, ensuring the effectiveness of NMP solution recovery.

[0024] 8. Semiconductor cooling chips can be powered by solar panels and municipal power grids, further realizing energy utilization and reducing energy loss.

[0025] 9. The output end of the solar panel is connected to an energy storage container, which can store the excess electricity generated by the solar panel. Both the solar panel and the energy storage container are electrically connected to a CNC matching device, and the CNC matching device is electrically connected to each thermoelectric cooler through a circuit distribution box. Thus, the solar panel can directly supply power to the thermoelectric cooler or the energy storage container can supply power to the thermoelectric cooler, effectively realizing the full utilization of the electrical energy generated by the solar panel.

[0026] 10. The energy storage container is also electrically connected to the output end of the municipal power grid, so that the energy storage container can be fully charged through the municipal power grid, and can also store energy during off-peak hours of the municipal power grid, effectively reducing electricity costs. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the structure of the present invention.

[0028] Figure 2 This is a schematic diagram of the cross-sectional distribution structure of the reheat finned inner tube and the condensation reheat mechanism of the present invention.

[0029] In the diagram: 10. Power supply mechanism; 11. Solar panel; 12. CNC matching unit; 13. Circuit distribution box; 14. Energy storage container; 15. Municipal power grid; 20. Condensation and reheat mechanism; 21. Condensation fin inner tube; 22. Reheat fin outer tube; 23. Semiconductor cooling chip; 24. Air duct; 30. Oven mechanism; 31. Positive electrode coating oven; 32. Return air duct; 33. Return air fan; 34. Exhaust air duct; 35. Exhaust fan; 40. Recycling mechanism; 41. NMP recycling pump; 42. Recycling pipeline; 43. NMP recycling tank. Detailed Implementation

[0030] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] For ease of understanding, the specific structure and operation of the present invention will be further described below with reference to the accompanying drawings:

[0032] The specific structure of this invention is as follows: Figure 1-2 As shown, its main structure includes a power supply mechanism 10, a condensation and reheat mechanism 20, an oven mechanism 30, and a recovery mechanism 40. Among them,

[0033] Condensation and reheat mechanism 20 Figure 1 and Figure 2 As shown, the condensation and reheat mechanism 20 includes a condensing finned inner tube 21 with one end open and the other end sealed, and a reheating finned outer tube 22 with both ends sealed, coaxially spaced outside the condensing finned inner tube 21. A semiconductor cooling chip 23 is embedded in the condensing finned inner tube 21, with the cooling end of the chip facing inward and the heating end facing outward, so that the inner cavity of the condensing finned inner tube 21 forms a condensation chamber, and the space between the condensing finned inner tube 21 and the reheating finned outer tube 22 forms a heating chamber. A guide air duct 24 connects the two tubes through the gap between the open end of the condensing finned inner tube 21 and the end of the reheating finned outer tube 22. External airflow enters the condensing chamber through the air inlet of the condensing finned inner tube 21, where water vapor condenses. The airflow is then guided through the guide air duct 24 into the heating chamber for reheating, and finally discharged through the exhaust port of the reheating finned outer tube 22, thus achieving reheating of the condensed gas. Specifically, the air inlet is located on the inner tube 21 of the condenser fins, away from the airflow duct 24, and the exhaust port is located on the outer tube 22 of the reheat fins, away from the airflow duct 24. This ensures the flow path of the airflow in the condenser and reheat chambers as much as possible, thereby achieving a good condensation effect in the condenser chamber and a good heating effect in the reheat chamber.

[0034] It is worth mentioning that the condensation and reheat mechanism 20 adopts a coaxial inner tube 21 for condensation fins and outer tube 22 for reheating fins. The space inside the outer tube 22 of the reheating fins is effectively utilized by the inner tube 21 of the condensation fins, thereby reducing the space required by the condensation and reheat mechanism 20. This allows the condensation and reheat mechanism 20 to achieve the reheating of the gas after condensation in a relatively compact space.

[0035] In specific implementation, the semiconductor cooling chip 23 can be configured as several groups distributed along the axial direction of the inner tube 21 of the condensing fins, and each group of semiconductor cooling chips 23 is provided with several evenly distributed on the outer periphery of the inner tube 21 of the condensing fins, thereby ensuring the uniformity of heating and cooling in the heating cavity and the condensing cavity.

[0036] In actual implementation, based on the coaxial and spaced distribution of the inner tube 21 of the condensing fins and the outer tube 22 of the reheating fins, both ends of the outer tube 22 of the reheating fins are connected to the air intake assembly of the external equipment through pipes, and both ends of the inner tube 21 of the condensing fins are connected to the exhaust assembly of the external equipment. By opening a connecting hole in the middle section of the inner tube 21 of the condensing fins to form a guide air duct 24, reheating after good airflow condensation can also be achieved.

[0037] Power supply mechanism 10 Figure 1 As shown, the power supply system 10 includes power supply from solar panels 11 and / or municipal power grid 15. The solar panels 11 can be directly connected to the CNC matching unit 12 or connected to the CNC matching unit 12 via an energy storage container 14. This allows the solar panels 11 to directly supply power to the semiconductor cooling chip 23 via the CNC matching unit 12 and the circuit distribution box 13. Excess energy from the solar panels 11 can also be stored in the energy storage container 14, effectively saving energy. The connection between the municipal power grid 15 and the energy storage container 14 allows the energy storage container 14 to be charged when the solar panels 11 generate insufficient power, ensuring sufficient power within the container. Additionally, the energy storage container 14 can store energy during off-peak hours on the municipal power grid 15.

[0038] Oven mechanism 30 Figure 1 As shown, the oven mechanism 30 includes a positive electrode coating oven 31. The positive electrode coating oven 31 is connected to the side of the inner tube 21 of the condenser fin away from the air guide channel through an exhaust duct 34, ensuring the flow path of the hot airflow discharged from the exhaust duct 34 in the condenser chamber and ensuring the condensation effect of water vapor in the hot airflow. The positive electrode coating oven 31 is connected to the side of the outer tube 22 of the reheat fin away from the air guide channel through a return air duct 32, ensuring the flow path of the cold airflow after condensation in the condenser chamber in the heating chamber and ensuring the heating effect of the cold airflow, so that the airflow returning to the positive electrode coating oven 31 through the return air duct 32 has a higher temperature.

[0039] It is worth mentioning that a return air fan 33 is installed on the return air duct 32 and an exhaust fan 35 is installed on the exhaust air duct 34. The arrangement of the return air fan 33 and the exhaust fan 35 effectively ensures the efficiency of gas circulation in the positive electrode coating oven 31, thereby accelerating the condensation efficiency of water vapor in the condensation chamber of the positive electrode coating oven 31, and thus improving the efficiency of drying lithium batteries in the positive electrode coating oven 31.

[0040] 40 recycling organizations Figure 1As shown, the recycling mechanism 40 includes an NMP recycling tank 43, which is connected to the drain end of the inner tube 21 of the condenser fins via a recycling pipe 42. The NMP solution discharged from the drain end of the inner tube 21 of the condenser fins is introduced into the NMP recycling tank 43 for storage via an NMP recycling pump 41. The NMP solution stored in the NMP recycling tank 43 is then sent to the mixing slurry for recycling.

[0041] In specific implementation, a chamber for storing NMP solution can be set in the inner tube 21 of the condenser fins. For example, the inner tube 21 of the condenser fins and the outer tube 22 of the reheat fins can be vertically distributed, and the open end of the inner tube 21 of the condenser fins faces upward. Through the bottom-sealed structure of the inner tube 21 of the condenser fins, the NMP solution can be stored through the bottom chamber of the inner tube 21 of the condenser fins, so that the drain end can be set at the bottom of the inner tube 21 of the condenser fins; or the inner tube 21 of the condenser fins can adopt a structure that is thick in the middle and thin at both ends. The NMP solution is stored in the inner cavity of the thick section of the inner tube 21 of the condenser fins, and the drain end can be set at the thick section of the inner tube 21 of the condenser fins.

[0042] Of course, those skilled in the art will recognize that the present invention is not limited to the details of the exemplary embodiments described above, but also includes the same or similar structures that can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0043] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

[0044] The technologies, shapes, and structures not described in detail in this invention are all known technologies.

Claims

1. A lithium battery positive electrode coating heat energy and NMP recovery device, characterized in that, The application relates to a condensation and reheating mechanism for a baking oven, which comprises a baking oven mechanism (30), a condensation and reheating mechanism (20) and a recovery mechanism (40), wherein the condensation and reheating mechanism (20) comprises a condensation fin inner tube (21) and a reheating fin outer tube (22) which are coaxially and spacedly arranged, the condensation fin inner tube (21) is embedded with semiconductor refrigerating sheets (23), the refrigerating end of the semiconductor refrigerating sheets (23) faces inwards, the heating end faces outwards, a condensation cavity is formed in the inner cavity of the condensation fin inner tube (21), a heating cavity is formed between the condensation fin inner tube (21) and the reheating fin outer tube (22), and a flow guide air channel (24) is arranged between the condensation cavity and the heating cavity, mixed gas discharged by the baking oven mechanism (30) flows back to the baking oven mechanism (30) through the gas inlet of the condensation fin inner tube (21) and then through the condensation cavity, the flow guide air channel (24) and the heating cavity and then through the gas outlet of the reheating fin outer tube (22), and the input end of the recovery mechanism (40) is communicated with the liquid outlet end of the condensation fin inner tube (21). The condensation fin inner tube (21) is of an open-end sealed structure, the reheating fin outer tube (22) is of a double-end sealed structure, and a gap is formed between the open end of the condensation fin inner tube (21) and the end of the reheating fin outer tube (22), which forms the flow guide air channel (24), and the gas inlet and the gas outlet are communicated with the gas discharge structure and the gas inlet structure of the baking oven mechanism (30) respectively.

2. The device for recovering heat and NMP from the coating of positive electrodes for lithium batteries according to claim 1, characterized in that, The semiconductor refrigerating sheets (23) are arranged in groups along the axial direction of the condensation fin inner tube (21), and each group of semiconductor refrigerating sheets (23) is arranged in a plurality of semiconductor refrigerating sheets which are uniformly distributed in the circumferential direction of the condensation fin inner tube (21).

3. The device for recovering heat and NMP according to claim 2, wherein the device is used for recovering heat and NMP in the production of positive electrode of lithium battery. The baking oven mechanism (30) comprises a positive electrode coating oven (31), the gas inlet is located on the condensation fin inner tube (21) and is away from the flow guide air channel (24), the gas outlet is located on the reheating fin outer tube (22) and is away from the flow guide air channel (24), the positive electrode coating oven (31) is communicated with the gas inlet through an air outlet pipeline (34), and the positive electrode coating oven (31) is communicated with the gas outlet through an air return pipeline (32).

4. The device for recovering heat and NMP according to claim 3, wherein the device is used for recovering heat and NMP in the production of positive electrode of lithium battery. An air return fan (33) is arranged on the air return pipeline (32), and an air outlet fan (35) is arranged on the air outlet pipeline (34).

5. The device for recovering heat and NMP according to any one of claims 1-4, wherein the device is used for recovering heat and NMP in the production of positive electrodes of lithium batteries. The recovery mechanism (40) comprises an NMP recovery tank (43), the NMP recovery tank (43) is communicated with the liquid outlet end of the condensation fin inner tube (21) through a recovery pipeline (42), and the output end of the NMP recovery tank (43) is connected with a slurry mixing device.

6. The device for recovering heat and NMP according to claim 5, wherein An NMP recovery pump (41) is arranged on the recovery pipeline (42).

7. The device for recovering heat and NMP according to any one of claims 2-4, wherein the device is used for recovering heat and NMP in the production of positive electrodes of lithium batteries. The semiconductor refrigerating sheets (23) are powered by a power supply mechanism (10), and the power supply mechanism (10) comprises a solar cell panel (11) and a municipal power grid (15).

8. The device for recovering heat and NMP according to claim 7, wherein the device is used for recovering heat and NMP in the production of positive electrode of lithium battery. The output end of the solar cell panel (11) is connected with an energy storage container (14) and a numerical control matching device (12), the output end of the energy storage container (14) is electrically connected with the numerical control matching device (12), and the numerical control matching device (12) is electrically connected with each semiconductor refrigerating sheet (23) through a circuit distribution box (13).

9. The device for recovering heat and NMP according to claim 8, wherein the device is used for recovering heat and NMP in the production of positive electrode of lithium battery. The energy storage container (14) is also electrically connected to an output of a municipal power grid (15).

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