A battery energy storage cooling system capable of cooling and heating

Abstract

The application discloses a battery energy storage cooling system capable of refrigeration and heating, comprising a wind-cooled heat pump unit, a CO2 cooling loop and a battery energy storage box group, the CO2 cooling loop uses the phase change of CO2 to refrigerate the battery energy storage box, the wind-cooled heat pump unit comprises a liquid storage tank, a first heat exchanger, a heat pump and a second heat exchanger, the first heat exchanger is coupled with the CO2 cooling loop to refrigerate or heat the CO2 cooling loop, the first heat exchanger is connected with a four-way joint through a pipeline, the four-way joint is connected with the inlet and outlet of the heat pump and the second heat exchanger, the second heat exchanger is connected with the liquid storage tank through a pipeline, the liquid storage tank is connected with the first heat exchanger through a pipeline, when refrigeration is needed, the four-way joint is controlled to connect the outlet of the heat pump with the first heat exchanger and the inlet with the second heat exchanger; when heating is needed, the four-way joint is controlled to connect the inlet of the heat pump with the first heat exchanger and the outlet with the second heat exchanger, so that the heating efficiency is improved by using a simple structure.

Description

Technical Field

[0001] This invention relates to the field of cooling technology, specifically to a battery energy storage cooling system capable of both cooling and heating. Background Technology

[0002] With the development of new energy power generation, lithium battery energy storage systems are widely used. However, lithium battery performance is significantly affected by temperature, especially in low-temperature environments, which can easily lead to capacity reduction and increased internal resistance. Existing lithium battery energy storage systems are equipped with cooling systems. In winter, when the ambient temperature is low, the lithium battery temperature is below the normal charging and discharging temperature. Most existing energy storage systems use electric heating to raise the lithium battery temperature. Once the temperature reaches the lithium battery's operating temperature, the energy storage system is activated to begin charging and discharging. During the charging and discharging process, the lithium battery generates heat, requiring the cooling system to be activated again to maintain the lithium battery at a suitable operating temperature. However, electric heating for lithium battery heating suffers from slow response and high energy consumption. Summary of the Invention

[0003] To overcome the shortcomings of the above-mentioned related technologies, this application provides a battery energy storage cooling system that can both cool and heat, featuring high heating efficiency and a simple system architecture.

[0004] The technical solution adopted by this invention to solve the technical problem is as follows: a battery energy storage cooling system capable of both cooling and heating, comprising an air-cooled heat pump unit, a CO2 cooling circuit, and a battery energy storage tank. The CO2 cooling circuit utilizes the phase change of CO2 to cool the battery energy storage tank. The air-cooled heat pump unit includes a liquid storage tank, a first heat exchanger, a heat pump, and a second heat exchanger. The first heat exchanger is coupled to the CO2 cooling circuit for either cooling or heating. The first heat exchanger is connected to a four-way connector via a pipe. The four-way connector is connected to the inlet and outlet of the heat pump and the second heat exchanger, respectively. The second heat exchanger is connected to the liquid storage tank via a pipe. The liquid storage tank is connected to the first heat exchanger via a pipe. When cooling is required, the four-way connector can be controlled to connect the outlet of the heat pump to the first heat exchanger and the inlet of the heat pump to the second heat exchanger. When heating is required, the four-way connector can be controlled to connect the inlet of the heat pump to the first heat exchanger and the outlet of the heat pump to the second heat exchanger.

[0005] Preferably, a gas-liquid separation device is installed on the pipe at the heat pump inlet, and a filter device is installed on the pipe between the second heat exchanger and the storage tank.

[0006] Preferably, the CO2 cooling circuit includes a CO2 storage tank and a heat exchanger, the battery energy storage group includes several battery boxes, the CO2 storage tank is connected to each battery box via pipelines, and each battery box is connected to the CO2 storage tank via a heat exchanger after being connected by pipelines. A circulation pump is installed on the pipelines, and the heat exchanger is coupled to a first heat exchanger. Preferably, a fire-fighting pipeline is connected to the aggregated pipeline, and several CO2 gas nozzles are installed on the fire-fighting pipeline.

[0007] Preferably, a safety valve is installed on the CO2 storage tank, and a one-way check valve is installed on the pipeline before the CO2 flows into the heat exchanger.

[0008] Preferably, the battery box includes a box body, a box cover, and a plurality of lithium battery packs. The box body is filled with coolant, the lithium batteries are installed in the box body and immersed in the coolant, and a CO2 flow channel is provided in the bottom plate of the box body. The pipes are respectively connected to the CO2 flow channel of each battery box.

[0009] Preferably, the battery box includes a box body, a box cover, a plurality of lithium battery packs and cooling coils. The box body is filled with coolant, the lithium battery packs are installed in the box body, the lithium batteries are immersed in the coolant, and the cooling coils are evenly distributed in the gaps between the lithium battery packs.

[0010] Preferably, the lithium battery pack includes several lithium batteries, and the two ends of each row of lithium battery packs are fixedly connected to the bottom of the box through a fixing frame, and each row of lithium battery packs is provided with a horizontal strap.

[0011] Compared with related technologies, the present invention has the following advantages: This battery energy storage cooling system uses an air-cooled heat pump unit, which can simultaneously meet the cooling and heating needs during system operation. It can provide a suitable operating temperature for lithium batteries without the need for an additional independent electric heater or water heating system.

[0012] High heating efficiency: Traditional electric heating (PTC) methods typically have a coefficient of performance (COP) of less than 1, meaning that consuming 1kW of electrical energy can only produce a maximum of 1kW of heat. In contrast, heat pump heating typically has a COP of 2.0-4.0 or even higher, meaning that consuming 1kW of electrical energy can transfer 2-4kW of heat from the air to the battery compartment, reducing heating energy consumption by 50%-75% compared to pure electric heating. Precise temperature control: Precise temperature control can be implemented based on the battery's optimal operating temperature range (25±10℃), avoiding energy waste caused by excessive cooling or heating.

[0013] Simplified system configuration: Eliminating the need for separate procurement, installation, and interface matching of heating systems (such as electric heating elements and complex water circuits) results in a simpler system architecture and reduces potential points of failure. Guaranteed ultra-low temperature start-up: For energy storage power stations in frigid regions, air-cooled heat pump units can provide a stable heat source, ensuring that lithium batteries can quickly warm up to a chargeable / dischargeable state in extremely low winter temperatures, thus guaranteeing system availability. Attached Figure Description

[0014] Figure 1This is a schematic diagram of the structure of Example 1; Figure 2 A schematic diagram of the airflow direction during cooling by an air-cooled heat pump unit; Figure 3 A schematic diagram of the airflow direction during cooling by an air-cooled heat pump unit; Figure 4 This is a schematic diagram of the battery energy storage box structure; Figure 5 This is a schematic diagram of the CO2 flow channel on the bottom plate of the battery energy storage box; Figure 6 This is a schematic diagram of the battery storage box after the cover is opened in Example 2. Detailed Implementation

[0015] First, those skilled in the art should understand that these embodiments are merely used to explain the technical principles of the embodiments of this application and are not intended to limit the scope of protection of the embodiments of this application. Those skilled in the art can make adjustments as needed to adapt to specific application scenarios.

[0016] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0017] Example 1 like Figure 1-5 As shown, a battery energy storage cooling system capable of both cooling and heating includes an air-cooled heat pump unit 1, a CO2 cooling circuit 2, and a battery energy storage box 3. The CO2 cooling circuit utilizes the phase change of CO2 to cool the battery energy storage box, and the air-cooled heat pump unit 1 provides cooling or heating for the CO2 in the CO2 cooling circuit.

[0018] The air-cooled heat pump unit includes a liquid storage tank 11, a first heat exchanger 12, a heat pump 13, and a second heat exchanger 14. The first heat exchanger 12 is coupled to a CO2 cooling circuit 2 for either cooling or heating. The first heat exchanger 12 is connected to a four-way connector 15 via a pipe. The four-way connector 15 is connected to the inlet and outlet of the heat pump and the second heat exchanger 14, respectively. The second heat exchanger 14 is connected to the liquid storage tank 11 via a pipe. A filter device 16 is installed on the pipe between the second heat exchanger 14 and the liquid storage tank 11. The liquid storage tank 11 is connected to the first heat exchanger 12 via a pipe. When cooling is required, the four-way connector 15 can be controlled to connect the heat pump outlet to the first heat exchanger 12 and the heat pump inlet to the second heat exchanger 14. A gas-liquid separator 17 is installed on the pipe at the heat pump inlet. When heating is required, the four-way connector 15 can be controlled to connect the heat pump inlet to the first heat exchanger 12 and the heat pump outlet to the second heat exchanger 14. The air-cooled heat pump unit uses Freon as its operating medium, and the liquid Freon storage tank 11 is used to store liquid Freon. The second heat exchanger 14 is placed outdoors, dissipating heat to the outdoor environment during cooling and absorbing heat energy from the environment during heating, thereby saving energy consumption when heating the battery storage box.

[0019] Cooling mode operation: When the battery needs to be cooled, the air-cooled heat pump unit 1 operates in cooling mode, absorbing heat from the energy storage compartment or battery pack through the CO2 cooling circuit 2, and then discharging the absorbed heat into the environment through the second heat exchanger 14 to cool the lithium battery and avoid performance degradation, shortened life and thermal runaway risks caused by high temperature.

[0020] Heating Mode Operation: When the lithium battery requires heating, the air-cooled heat pump unit operates in heating mode. Utilizing a reverse circulation principle, it absorbs low-grade heat energy from the outdoor air, compresses it, and converts it into high-grade heat energy. This heat is then released into the battery compartment through the CO2 cooling circuit 2. At this time, liquid CO2 circulates within the CO2 cooling circuit 2. Because the lithium battery temperature is below the CO2 phase change temperature, the liquid CO2 does not undergo an endothermic phase change as it flows through the battery storage tank. The first heat exchanger 12 can heat the liquid CO2. Since the temperature of the liquid CO2 is higher than the temperature of the battery storage tank, the liquid CO2 can heat the lithium battery, bringing it to a suitable operating temperature.

[0021] The CO2 cooling circuit 2 includes a CO2 storage tank 21, a circulating pump 22, and circulating pipes. The battery energy storage group includes several battery boxes 31. A safety valve is installed on the CO2 storage tank 21. The CO2 storage tank 21 is connected to each battery box 31 through pipes. The battery boxes 31 are connected to the CO2 storage tank 21 through pipes and then to the first heat exchanger 12. The circulating pump 22 is installed on the circulating pipes. A one-way check valve 24 is installed on the circulating pipes before the collected energy flows into the first heat exchanger 12.

[0022] The combined circulation pipeline is connected to a fire-fighting pipeline 23, and several CO2 gas nozzles are installed on the fire-fighting pipeline 23.

[0023] The battery box 31 includes a box body 32, a box cover 33, and several lithium battery packs 34. The box body 32 is filled with coolant, and the lithium battery packs 34 are installed in the box body and immersed in the coolant. The bottom plate of the box body 32 is provided with a CO2 flow channel 35, and the circulation pipes are connected to the CO2 flow channel of each battery box.

[0024] In another embodiment, the battery box includes a box body 32, a box cover 33, a plurality of lithium battery packs 34 and a cooling coil 36. The box body 32 is filled with coolant, the lithium battery packs 34 are installed in the box body and are immersed in the coolant, and the cooling coils 36 are evenly distributed in the gaps between the lithium battery packs. The circulation pipes are connected to the cooling coils 36 of each battery box.

[0025] Example 2 like Figure 6As shown, the battery box includes a box body 32, a box cover, several lithium battery packs 34 and cooling coils 36. The box body 32 is filled with coolant. The lithium battery packs 34 are installed in the box body and are immersed in the coolant. The cooling coils 36 are evenly distributed in the gaps between the lithium battery packs. The circulation pipes are connected to the cooling coils 36 of each battery box. The rest is the same as in Embodiment 1.

[0026] This battery energy storage cooling system uses an air-cooled heat pump unit, which can simultaneously meet the cooling and heating needs during system operation. It can provide a suitable operating temperature for lithium batteries without the need for an additional independent electric heater or water heating system.

[0027] High heating efficiency: Traditional electric heating (PTC) methods typically have a coefficient of performance (COP) of less than 1, meaning that consuming 1kW of electrical energy can only produce a maximum of 1kW of heat. In contrast, heat pump heating typically has a COP of 2.0-4.0 or even higher, meaning that consuming 1kW of electrical energy can transfer 2-4kW of heat from the air to the battery compartment, reducing heating energy consumption by 50%-75% compared to pure electric heating. Precise temperature control: Precise temperature control can be implemented based on the battery's optimal operating temperature range (25±10℃), avoiding energy waste caused by excessive cooling or heating.

[0028] Simplified system configuration: Eliminating the need for separate procurement, installation, and interface matching of heating systems (such as electric heating elements and complex water circuits) results in a simpler system architecture and reduces potential points of failure. Guaranteed ultra-low temperature start-up: For energy storage power stations in frigid regions, air-cooled heat pump units can provide a stable heat source, ensuring that lithium batteries can quickly warm up to a chargeable / dischargeable state in extremely low winter temperatures, thus guaranteeing system availability.

[0029] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A battery energy storage cooling system capable of both cooling and heating, characterized in that, The system includes an air-cooled heat pump unit, a CO2 cooling circuit, and a battery energy storage tank. The CO2 cooling circuit utilizes the phase change of CO2 to cool the battery energy storage tank. The air-cooled heat pump unit includes a liquid storage tank, a first heat exchanger, a heat pump, and a second heat exchanger. The first heat exchanger is coupled to the CO2 cooling circuit for either cooling or heating. The first heat exchanger is connected to a four-way connector via a pipe. The four-way connector is connected to the inlet and outlet of the heat pump and the second heat exchanger, respectively. The second heat exchanger is connected to the liquid storage tank via a pipe. The liquid storage tank is connected to the first heat exchanger via a pipe. When cooling is required, the four-way connector can be controlled to connect the heat pump outlet to the first heat exchanger and the heat pump inlet to the second heat exchanger. When heating is required, the four-way connector can be controlled to connect the heat pump inlet to the first heat exchanger and the heat pump outlet to the second heat exchanger.

2. The battery energy storage cooling system capable of both cooling and heating according to claim 1, characterized in that, A gas-liquid separation device is installed on the pipe at the heat pump inlet, and a filter device is installed on the pipe between the second heat exchanger and the storage tank.

3. The battery energy storage cooling system capable of both cooling and heating according to claim 1, characterized in that, The CO2 cooling circuit includes a CO2 storage tank, a circulating pump, and a circulating pipeline. The battery energy storage box group includes several battery boxes. The CO2 storage tank is connected to each battery box through a circulating pipeline. Each battery box is connected to the CO2 storage tank through a heat exchanger after the circulating pipeline is connected. A circulating pump is installed on the circulating pipeline. The heat exchanger is coupled to the first heat exchanger.

4. The battery energy storage cooling system capable of both cooling and heating according to claim 3, characterized in that, The consolidated circulation pipeline is connected to a fire-fighting pipeline, and several CO2 gas nozzles are installed on the fire-fighting pipeline.

5. The lithium battery energy storage cooling system according to claim 3, characterized in that, The CO2 storage tank is equipped with a safety valve, and the circulating pipeline before the CO2 flows into the heat exchanger is equipped with a one-way check valve.

6. The battery energy storage cooling system capable of both cooling and heating according to claim 3, characterized in that, The battery box includes a box body, a box cover, and several lithium battery packs. The box body is filled with coolant, and the lithium batteries are installed in the box body and immersed in the coolant. The bottom plate of the box body is provided with a CO2 flow channel, and the circulation pipe is connected to the CO2 flow channel of each battery box.

7. The battery energy storage cooling system capable of both cooling and heating according to claim 3, characterized in that, The battery box includes a box body, a box cover, several lithium battery packs and cooling coils. The box body is filled with coolant, the lithium battery packs are installed in the box body and are immersed in the coolant, and the cooling coils are evenly distributed in the gaps between the lithium battery packs.

8. A battery energy storage cooling system capable of both cooling and heating according to any one of claims 6-7, characterized in that, The lithium battery pack includes several lithium batteries. The two ends of each row of lithium battery packs are fixedly connected to the bottom of the box through a fixing frame. Each row of lithium battery packs is provided with a horizontal strap.

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