All-vanadium redox flow battery heat dissipation and heat energy recovery integrated device

Abstract

This invention discloses an integrated heat dissipation and heat recovery device for vanadium redox flow batteries, relating to the technical field of vanadium redox flow batteries. The invention employs a three-stage waste heat recovery design: In the first stage, hot air from the energy storage device is transferred to an air-cooled heat exchanger via an external fan, where it undergoes initial heat exchange with the cold medium on the condenser side of the heat pump; in the second stage, cold water enters a heat dissipation coil outside the electrolyte storage tank and exchanges heat with the electrolyte inside the tank, resulting in warm water with a certain heat grade entering a buffer tank to mix with the cold medium recovered in the first stage; in the third stage, a heat transfer medium exchanges heat with the electrolyte inside a heat exchanger, then transfers the heat to the heat pump module. The heat exchange medium absorbs heat on the evaporation side and releases heat on the condensation side, then the high-grade heat medium exchanges heat with the cold medium water in the buffer tank via a plate heat exchanger, and the resulting hot water enters a storage tank for storage.

Description

Technical Field

[0001] This invention relates to the technical field of vanadium redox flow batteries, and more specifically to an integrated device for heat dissipation and heat recovery of vanadium redox flow batteries. Background Technology

[0002] During charging and discharging, vanadium redox flow batteries undergo electrochemical reactions accompanied by endothermic and exothermic processes, leading to temperature changes in the electrolyte solution, the energy storage medium of the battery system. The generation and absorption of heat mainly include reaction heat, polarization heat, Joule heat, self-discharge heat, and the conversion of mechanical energy into thermal energy. Currently, the DC-side charge-discharge efficiency of vanadium redox flow batteries reaches 75%–80%, with an energy loss rate of 20–25%. Based on measurements and statistics of actual operating data from typical vanadium redox flow batteries, approximately 15% of the charging energy, or 60–75% of the total energy loss, is converted into heat energy and stored in the electrolyte solution of the battery system.

[0003] In a vanadium redox flow battery system, the heat generated and the resulting temperature changes in the electrolyte and other components affect the electrolyte's cycle stability, capacity utilization, and battery efficiency. According to theoretical and practical research, within a certain temperature range, as the electrolyte temperature increases, the battery system's conversion efficiency and battery capacity both improve to varying degrees. However, as the electrolyte temperature exceeds a certain range, the electrolyte's operational stability faces higher risks. Excessively high temperatures can cause pentavalent vanadium ions to precipitate, leading to stack blockage and safety hazards. Therefore, an independent heat exchanger is needed to manage the electrolyte's heat exchange and ensure the system's safe and normal operation.

[0004] In summary, existing vanadium redox flow batteries use independent heat exchangers to exchange heat with the electrolyte. However, the heat generated after heat exchange using traditional heat exchange systems is directly discharged into the atmosphere, failing to effectively utilize this heat and resulting in a significant waste of heat. Summary of the Invention

[0005] The purpose of this invention is to provide an integrated device for heat dissipation and heat recovery of vanadium redox flow batteries, so as to overcome the above-mentioned defects in the prior art.

[0006] An integrated device for heat dissipation and heat recovery of vanadium redox flow battery includes a stack in a power unit container and an electrolyte storage tank in a capacity unit container. The stack is connected to the electrolyte storage tank through pipelines.

[0007] The primary waste heat recovery system includes a fan and an air-cooled heat exchanger. The hot air inside the power unit container and the capacity unit container is transported to the air-cooled heat exchanger through the fan on the exhaust duct. The cold water pipe connected to the inlet of the air-cooled heat exchanger is used for heat exchange. The outlet of the air-cooled heat exchanger is connected to the buffer water tank.

[0008] The secondary waste heat recovery system includes a heat dissipation coil installed on the outside of the electrolyte storage tank. The cold water inlet of the heat dissipation coil is connected to a cold water pipe, and the warm water outlet of the heat dissipation coil is connected to a buffer water tank to mix with the cold medium after the primary waste heat recovery.

[0009] The three-stage waste heat recovery system includes an evaporator and a heat pump unit. The evaporator inside the capacity unit container is connected to the heat pump unit, which is connected to a plate heat exchanger. The high-grade heat medium exchanges heat with the cold medium water in the buffer tank through the plate heat exchanger, and the produced hot water enters the hot water storage tank for storage.

[0010] Preferably, the ventilator is electrically connected to the BMS system via a ventilator controller.

[0011] Preferably, both the power unit container and the capacity unit container are provided with air inlets on the top and air ducts inside, and the air ducts are connected to the exhaust pipes through exhaust outlets.

[0012] Preferably, a constant pressure water supply tank is provided between the heat pump unit and the evaporator, and between the heat pump unit and the plate heat exchanger.

[0013] Preferably, the hot water storage tank is connected to the overflow storage tank via an overflow valve, and the hot water storage tank and the overflow storage tank are respectively connected to the bathing system, while the overflow storage tank is connected to the kitchen system.

[0014] Preferably, an electric valve is provided between the cold water inlet of the heat dissipation coil and the cold water pipe.

[0015] The present invention has the following advantages:

[0016] 1. Traditional heat exchangers exchange heat between the refrigerant medium and the electrolyte in the evaporator, and then dissipate the heat into the atmosphere through a fan. This invention uses a waste heat recovery device to extract heat from the electrolyte and the inside of the energy storage device to the greatest extent possible. The hot water produced can meet the hot water needs of the plant area where the energy storage device is located, thus maximizing the utilization of waste heat.

[0017] 2. This invention employs a three-stage waste heat recovery design: Stage 1 waste heat recovery involves designing air ducts and exhaust vents inside the power unit container and capacity unit container. Hot air inside the energy storage device is transferred to the air-cooled heat exchanger via external fans and exhaust pipes, where it undergoes initial heat exchange with the cold medium on the heat pump's condenser side, improving the initial heat quality of the cold medium. Stage 2 waste heat recovery involves designing a heat dissipation coil outside the electrolyte storage tank inside the capacity unit container. Cold water enters the coil and exchanges heat with the electrolyte inside the tank. Warm water with a certain heat quality enters the buffer tank and mixes with the cold medium recovered in Stage 1, then supplies the condenser side water demand of the heat pump. Stage 3 waste heat recovery involves heat exchange between the transfer medium and the electrolyte inside the heat exchanger. The transfer medium then transfers heat to the heat pump module. The heat exchange medium absorbs heat on the evaporation side and releases heat on the condensation side. The high-grade heat medium then exchanges heat with the cold medium water in the buffer tank via a plate heat exchanger, and the resulting hot water enters the storage tank for storage.

[0018] 3. By calculating the heat generated during the operation of the energy storage system and the hot water output of the three-stage waste heat recovery device, this invention incorporates a combination design of a hot water storage tank and an overflow tank in the hot water storage device. The hot water storage tank ensures the necessary hot water demand of the plant area, while the overflow tank can supply hot water for the kitchen and other areas. This design ensures the hot water demand while avoiding the use of a heat dissipation tower and reducing the power consumption of auxiliary equipment.

[0019] 4. Vanadium redox flow batteries have lower system conversion efficiency than lithium batteries, mainly because heat loss is not collected and reused. By adopting a three-stage waste heat recovery device, efficient recovery and reuse of waste heat is achieved, reducing the power consumption for preparing daily hot water in the factory area where the equipment is located, which is equivalent to improving the conversion efficiency of the vanadium redox flow battery system.

[0020] 5. This invention achieves controllable adjustment of primary waste heat recovery by setting temperature measuring points inside the power unit container and capacity unit container of the primary waste heat recovery system. The data from these measuring points is uploaded to the BMS in real time, allowing the BMS to control the start and stop of the ventilation fan based on the real-time temperature. For secondary waste heat recovery, temperature measuring points are set on the outlet water pipe, and the data from these measuring points is uploaded to the BMS in real time. The BMS can then control the opening and stopping of the inlet valve based on the outlet water temperature, achieving controllable adjustment of secondary waste heat recovery. Furthermore, high and low level sensors are installed in the buffer water tank, and the sensor data is uploaded to the BMS in real time. When the buffer tank reaches full level, the BMS issues a command to close the primary waste heat recovery fan and the secondary waste heat recovery inlet valve. When the buffer tank level falls below the low level, the BMS issues a command to open the primary waste heat recovery fan and the secondary waste heat recovery inlet valve, achieving fully automated control. This combined primary and secondary control has a higher priority than the primary and secondary waste heat recovery controls. Only when the combined primary and secondary control allows the primary waste heat recovery fan and the secondary waste heat recovery inlet valve to open, can the primary and secondary waste heat recovery controls function independently. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the overall angular structure of the present invention.

[0022] Figure 2 This is a schematic diagram of the internal air duct of the rate unit container and capacity unit container of the present invention.

[0023] Figure 3 This is a schematic diagram of the heat dissipation coil structure of the present invention.

[0024] Figure 4 This is a flowchart of the combined control process for primary and secondary waste heat recovery in this invention.

[0025] Figure 5 This is a flowchart of the automatic control process for primary waste heat recovery according to the present invention.

[0026] Figure 6 This is a flowchart of the automatic control process for secondary waste heat recovery according to the present invention.

[0027] The components include: 1. Power unit container, 2. Capacity unit container, 3. Ventilation fan, 4. Exhaust duct, 5. Air-cooled heat exchanger, 6. Cold water pipe, 7. Buffer water tank, 8. Radiating coil, 9. Evaporator, 10. Heat pump unit, 11. Plate heat exchanger, 12. Hot water storage tank, 13. Air inlet, 14. Air duct, 15. Exhaust outlet, 16. Constant pressure water supply tank, 17. Overflow storage tank, and 18. Electric valve. Detailed Implementation

[0028] The following detailed description of the embodiments, with reference to the accompanying drawings, will further illustrate the specific implementation of the present invention, in order to help those skilled in the art to have a more complete, accurate, and in-depth understanding of the concept and technical solutions of the present invention.

[0029] like Figure 1-6 As shown, the present invention provides an integrated device for heat dissipation and heat recovery of vanadium redox flow batteries, including a battery stack in a power unit container 1 and an electrolyte storage tank in a capacity unit container 2. The battery stack is connected to the electrolyte storage tank through pipelines.

[0030] The primary waste heat recovery system includes a fan 3 and an air-cooled heat exchanger 5. Hot air inside the power unit container 1 and the capacity unit container 2 is transported to the air-cooled heat exchanger 5 through the fan 3 on the exhaust pipe 4. Heat exchange is performed through the cold water pipe 6 connected to the inlet of the air-cooled heat exchanger 5 to improve the initial heat quality of the cold medium. The outlet of the air-cooled heat exchanger 5 is connected to the buffer water tank 7. The fan 3 is electrically connected to the BMS system through the fan controller.

[0031] The secondary waste heat recovery system includes a heat dissipation coil 8 installed on the outside of the electrolyte storage tank. The cold water inlet of the heat dissipation coil 8 is connected to the cold water pipe 6. An electric valve 18 is installed between the cold water inlet of the heat dissipation coil 8 and the cold water pipe 6. The electric valve 18 controls the cold water from the cold water pipe 6 to enter the heat dissipation coil 8. The warm water outlet of the heat dissipation coil 8 is connected to the buffer water tank 7. After the cold water enters the heat dissipation coil 8, it exchanges heat with the electrolyte inside the electrolyte storage tank. The warm water with a certain heat quality enters the buffer water tank 7 and mixes with the cold medium after the primary waste heat recovery, and then supplies the condensate side water demand of the heat pump recovery.

[0032] The three-stage waste heat recovery system includes an evaporator 9 and a heat pump unit 10. The evaporator 9 inside the capacity unit container 2 is connected to the heat pump unit 10, and the heat pump unit 10 is connected to the plate heat exchanger 11. Heat exchange occurs between the heat pump unit and the electrolyte through a transfer medium inside the heat exchanger. The transfer medium then transfers the heat to the heat pump module. The heat exchange medium absorbs heat on the evaporation side and releases heat on the condensation side. The high-grade heat medium then exchanges heat with the cold medium water in the buffer tank through the plate heat exchanger 11. The produced hot water enters the storage tank for storage. The hot water storage tank 12 is connected to the overflow storage tank 17 through an overflow valve. The hot water storage tank 12 and the overflow storage tank 17 are respectively connected to the bathing system, and the overflow storage tank 17 is connected to the kitchen system.

[0033] In addition, both the power unit container 1 and the capacity unit container 2 are provided with air inlets 13 on the top and air ducts 14 inside. The air ducts 14 are connected to the exhaust pipe 4 through exhaust outlets 15. The hot air inside the power unit container 1 and the capacity unit container 2 is discharged through the air ducts 14 and exhaust outlets 15 for heat exchange.

[0034] In addition, constant pressure water supply tanks 16 are provided between the heat pump unit 10 and the evaporator 9, and between the heat pump unit 10 and the plate heat exchanger 11, respectively, to replenish water to the pipelines between the heat pump unit 10 and the evaporator 9, and between the heat pump unit 10 and the plate heat exchanger 11.

[0035] Detailed implementation methods and principles:

[0036] In practical applications, temperature measuring points are installed inside the power unit and capacity unit containers of the primary waste heat recovery system. Data from these points is uploaded to the BMS (Battery Management System) in real time. The BMS can then control the start and stop of the ventilation fans based on the real-time temperature, achieving controllable adjustment of the primary waste heat recovery. For secondary waste heat recovery, temperature measuring points are installed on the outlet water pipe. Data from these points is also uploaded to the BMS in real time. The BMS can then control the start and stop of the inlet water valve based on the outlet water temperature, achieving controllable adjustment of the secondary waste heat recovery. Furthermore, high and low level sensors are installed in the buffer tank, and the sensor data is uploaded to the BMS in real time. When the buffer tank reaches full level, the BMS issues a command to close the primary waste heat recovery fan and the secondary waste heat recovery inlet valve. When the buffer tank level is below low level, the BMS issues a command to open the primary waste heat recovery fan and the secondary waste heat recovery inlet valve, achieving fully automated control. This combined primary and secondary control has a higher priority than the primary and secondary waste heat recovery controls. Only when the combined primary and secondary control allows the primary waste heat recovery fan and the secondary waste heat recovery inlet valve to open, can the primary and secondary waste heat recovery controls function independently.

[0037] The power unit and capacity unit generate a lot of heat during operation. The heat inside the equipment is carried out by the exhaust system 4 and used for heat exchange between the air-cooled heat exchanger 5 and the cold water to increase the temperature of the cold water. Modular coil heat exchangers 16 are installed around the electrolyte storage tank to further recover the heat around the storage tank and increase the temperature of the cold water. The basic cold water is heated by primary and secondary waste heat recovery and flows into the buffer water tank 6. After passing through the heat pump unit 8, the water temperature is reheated to 60°C to supply water for the dormitory and kitchen. The entire system solves the system cooling problem through three-stage heat recovery, while improving the working efficiency of the heat pump and reducing power consumption.

[0038] The present invention has been described above by way of example with reference to the accompanying drawings. Obviously, the specific implementation of the present invention is not limited to the above-described manner. Any non-substantial improvements made using the concept and technical solution of the present invention, or the direct application of the present invention and technical solution to other situations without modification, are all within the protection scope of the present invention.

Claims

1. An integrated device for heat dissipation and heat recovery of a vanadium redox flow battery, characterized in that: Includes a fuel cell stack in a power unit container (1) and an electrolyte storage tank in a capacity unit container (2), wherein the fuel cell stack is connected to the electrolyte storage tank via pipelines; The primary waste heat recovery system includes a fan (3) and an air-cooled heat exchanger (5). The hot air inside the power unit container (1) and the capacity unit container (2) is transported to the air-cooled heat exchanger (5) through the fan (3) on the exhaust pipe (4). The cold water pipe (6) connected to the inlet of the air-cooled heat exchanger (5) is used for heat exchange. The outlet of the air-cooled heat exchanger (5) is connected to the buffer water tank (7). The secondary waste heat recovery system includes a heat dissipation coil (8) installed on the outside of the electrolyte storage tank. The cold water inlet of the heat dissipation coil (8) is connected to the cold water pipe (6), and the warm water outlet of the heat dissipation coil (8) is connected to the buffer water tank (7) to mix with the cold medium after the primary waste heat recovery. The three-stage waste heat recovery system includes an evaporator (9) and a heat pump unit (10). The evaporator (9) inside the capacity unit container (2) is connected to the heat pump unit (10), and the heat pump unit (10) is connected to the plate heat exchanger (11). The high-grade heat medium exchanges heat with the cold medium water in the buffer tank through the plate heat exchanger (11), and the produced hot water enters the hot water storage tank (12) for storage. The ventilator (3) is electrically connected to the BMS system via a ventilator controller; Both the power unit container (1) and the capacity unit container (2) are provided with air inlets (13) on the top and air ducts (14) inside. The air ducts (14) are connected to the exhaust pipes (4) through the exhaust outlets (15).

2. The integrated heat dissipation and heat recovery device for a vanadium redox flow battery according to claim 1, characterized in that: A constant pressure water supply tank (16) is provided between the heat pump unit (10) and the evaporator (9), and between the heat pump unit (10) and the plate heat exchanger (11).

3. The integrated heat dissipation and heat recovery device for a vanadium redox flow battery according to claim 1, characterized in that: The hot water storage tank (12) is connected to the overflow storage tank (17) via an overflow valve. The hot water storage tank (12) and the overflow storage tank (17) are respectively connected to the bathing system, and the overflow storage tank (17) is connected to the kitchen system.

4. The integrated heat dissipation and heat recovery device for a vanadium redox flow battery according to claim 1, characterized in that: An electric valve (18) is provided between the cold water inlet of the heat dissipation coil (8) and the cold water pipe (6).

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