Liquid cooling energy storage temperature control system and control method

Abstract

The invention discloses a liquid cooling energy storage temperature control system and a control method, and belongs to the technical field of cooling, the liquid cooling energy storage temperature control system comprises a PCS cooling system, a refrigerant circulation system and a battery PACK cooling system, the PCS cooling system is communicated with the refrigerant circulation system through the battery PACK cooling system; the PCS cooling system comprises a PCS, a first water pump, a first valve, a fan and an air-water heat exchanger. The battery PACK heat dissipation system and the PCS heat dissipation system share one set of refrigeration system, the fan enhances the heat exchange efficiency of the air-water heat exchanger and the condenser at the same time, the device consumption is reduced, the air-water heat exchanger does not occupy the cooling capacity of the compressor during heat exchange, the system energy consumption is reduced, the heat dissipation effect is improved by adopting a liquid cooling heat dissipation mode, and the heat dissipation efficiency is improved. The front air inlet and upper air outlet design can be adopted, the PCS and the battery PACK water cooling machine are integrated into one, and the back-to-back requirement of equipment is met.

Description

Technical Field

[0001] The present invention relates to the technical field of data storage cooling, and in particular to a liquid cooling energy storage temperature control system and a control method. Background Art

[0002] With the support of national policies and the continuous increase in market demand, the energy density of industrial and commercial energy storage systems has gradually increased, and the demand for heat dissipation has increased accordingly. Improving the rationality of cooling capacity distribution of refrigeration equipment and reducing heat dissipation energy consumption have become important competitive advantages of energy storage systems. The layout of equipment in energy storage cabinets has become more compact, and the demand for miniaturization of supporting equipment has become increasingly strong; Traditional air-cooled PCS heat dissipation usually has air flow in front and air out at the back. This method cannot meet customers' requirements for "back-to-back" placement of equipment. The outlet water temperature of traditional liquid-cooled PCS refrigeration equipment is low, and the internal ambient temperature of the PCS is high, which is prone to condensation problems. It is also impossible to make the IGBT / SiC inside the PCS work at the optimal temperature; it is necessary to separate energy consumption for the PCS refrigeration equipment, which has high energy consumption and low integration; the outlet water temperature of traditional integrated refrigeration equipment is low, and the internal ambient temperature of the PCS is high, which is prone to condensation problems, and it is also impossible to make the IGBT / SiC inside the PCS work at the optimal temperature; it is necessary to separate energy consumption for the PCS refrigeration equipment, which has high energy consumption and complex overall design. Summary of the invention

[0003] The purpose of the present invention is to solve the problems existing in the prior art and to propose a liquid-cooled energy storage temperature control system and a control method.

[0004] In order to achieve the above object, the present invention adopts the following technical solutions: A liquid-cooled energy storage temperature control system, comprising a PCS cooling system, a refrigerant circulation system and a battery PACK cooling system, wherein the PCS cooling system is connected to the refrigerant circulation system through the battery PACK cooling system; The PCS cooling system includes a PCS, a first water pump, a first valve, a fan and a wind-water heat exchanger; The refrigerant circulation system includes a condenser, an expansion valve, a compressor and an evaporator; The battery PACK cooling system includes a heater, a second valve, a water storage tank, a second water pump, a third valve and a battery PACK.

[0005] As a preferred solution, the PCS cooling system further includes a first switch and a second switch, and the first switch and the second switch control pipeline are connected to the evaporator.

[0006] As a preferred solution, the first water pump is connected to the first valve and the wind-water heat exchanger through pipelines respectively, the wind-water heat exchanger is used in conjunction with a fan, and the first valve is connected to the second valve through a pipeline.

[0007] As a preferred solution, the second valve is respectively communicated with the heater and the water storage tank through pipelines, the water storage tank is communicated with the second water pump, and the battery PACK is respectively communicated with the second water pump and the third valve through pipelines.

[0008] As a preferred solution, the evaporator is respectively communicated with the third valve, the expansion valve and the compressor through pipelines, and the compressor is communicated with the expansion valve through the condenser.

[0009] A control method proposed for a liquid-cooled energy storage temperature control system includes the following steps: S1. The optimal operating temperature of the battery PACK is T5. When the energy storage system is not working and the detected ambient temperature is higher than T5, the refrigeration system is started, and the internal heat dissipation system of the battery is started to reduce the temperature of the battery PACK to T5. S2. When the detected ambient temperature is lower than T5, the PTC is started, and the internal heating system of the battery is started to raise the temperature of the battery PACK to T5. S3. When the energy storage system is working, the refrigeration system is turned on, and the heat dissipation systems of the battery PACK and the PCS are turned on to keep the temperature inside the battery PACK at T5 and the temperature of the PCS at T3.

[0010] As a preferred solution, the temperature range of T5 is 20°C - 30°C, and the temperature range of T3 is 80°C - 95°C.

[0011] As a preferred solution, temperature control is carried out by turning on the second switch (16). Turn on the first switch (17) for temperature control. At the same time, turn on the second switch (16) and the first switch (17) for temperature control.

[0012] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. The present invention shares a set of refrigeration systems for the heat dissipation systems of the battery PACK and the PCS. Among them, the fan simultaneously enhances the heat exchange efficiency of the water-air heat exchanger and the condenser, saving the usage of devices. The heat exchange of the water-air heat exchanger does not occupy the cooling capacity of the compressor, reducing the system energy consumption. This liquid-cooled heat dissipation method improves the heat dissipation effect, and a forward air intake and upward air outlet design can be adopted to integrate the PCS and the battery PACK water cooler into one to meet the "back-to-back" requirement of the equipment.

[0013] 2. The present invention adopts a dynamic cooling capacity distribution technology, intelligently adjusts the cooling capacity sharing between the PCS and the battery PACK through a switching valve, realizes on-demand cooling of the refrigeration system, reduces redundant energy consumption; the air-water heat exchanger and the compressor work together, and the fan improves the heat exchange efficiency at both places at the same time, avoiding the traditional compressor from running at full load continuously, and the comprehensive energy efficiency is increased by 20%-30%. Through the temperature zoning control strategy, the PCS operates at high temperature and high efficiency (80°C - 95°C), and the battery maintains a low-temperature safety range (20°C - 30°C), taking into account the energy saving of power devices and the battery life. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 Schematic diagram of a liquid-cooled energy storage temperature control system and control method proposed by the present invention Figure 1 ; Figure 2 Schematic diagram of a liquid-cooled energy storage temperature control system and control method proposed by the present invention Figure 2 .

[0015] In the figure: 1, PCS cooling system; 11, PCS; 12, first water pump; 13, first valve; 14, fan; 15, air-water heat exchanger; 16, second switch; 17, first switch; 2, refrigerant circulation system; 21, condenser; 22, expansion valve; 23, compressor; 24, evaporator; 3, battery PACK cooling system; 31, heater; 32, second valve; 33, water storage tank; 34, second water pump; 35, third valve; 36, PACK. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0016] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0017] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "upper", "lower", "inner", "outer", "top / bottom end", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present invention. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0018] In the description of the present invention, it should be noted that, unless otherwise clearly specified and defined, terms such as "installation", "provided with", "sheathed / connected", "connection", etc. should be understood in a broad sense. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0019] Example 1. Refer to Figure 1 , a liquid-cooled energy storage temperature control system, including a PCS (Power Conversion System) cooling system 1, a refrigerant circulation system 2, and a battery PACK cooling system 3. The PCS cooling system 1 is communicated with the refrigerant circulation system 2 through the battery PACK cooling system 3; The PCS cooling system 1 includes a PCS 11, a first water pump 12, a first valve 13, a fan 14, and a water-air heat exchanger 15; The refrigerant circulation system 2 includes a condenser 21, an expansion valve 22, a compressor 23, and an evaporator 24; The battery PACK cooling system 3 includes a heater 31, a second valve 32, a water storage tank 33, a second water pump 34, a third valve 35, and a battery PACK 36.

[0020] The first water pump 12 is respectively connected to the first valve 13 and the water-air heat exchanger 15 through pipelines. The water-air heat exchanger 15 is used in cooperation with the fan 14, and the first valve 13 is communicated with the second valve 32 through a pipeline.

[0021] The second valve 32 is respectively communicated with the heater 31 and the water storage tank 33 through pipelines. The water storage tank 33 is communicated with the second water pump 34, and the battery PACK 36 is respectively connected to the second water pump 34 and the third valve 35 through pipelines.

[0022] The evaporator 24 is respectively communicated with the third valve 35, the expansion valve 22, and the compressor 23 through pipelines. The compressor 23 is communicated with the expansion valve 22 through the condenser 21.

[0023] This solution can be used for silicon carbide (SiC) PCS. The internal resistance of SiC is greatly affected by temperature. The higher the temperature, the smaller its resistance and the lower the energy consumption. It is difficult for traditional cooling methods to make it work at the optimal working temperature T3 (80°C - 95°C); When the system is working, the cooling water of the battery PACK flows out from the water outlet of the battery PACK36, exchanges heat through the condenser 21 to the second water pump 34, and returns to the battery PACK36 for circulating heat dissipation; the refrigerant is compressed into a high-temperature and high-pressure gas by the compressor 23, condensed into a medium-temperature and high-pressure gas through the condenser 21, enters the expansion valve 22 to be depressurized into a low-temperature and low-pressure misty liquid state, then enters the condenser 21 to exchange heat with the cooling water in the battery PACK circuit, and finally returns to the compressor 23 to start the next cycle; the PCS cooling water flows out from the water outlet of the PCS11, exchanges heat through the air-water heat exchanger 15 to the first water pump 12, and returns to the PCS11 for circulating heat dissipation.

[0024] Based on Embodiment 1, Embodiment 2 is proposed. Refer to Figure 2 : The PCS cooling system 1 further includes a first switch 17 and a second switch 16, and the first switch 17 and the second switch 16 control the pipeline to communicate with the evaporator 24; The PCS can select the heat dissipation method according to the actual usage scenario. When the outlet water temperature is greater than t1, the cooling capacity is insufficient, and the first switch 17, the second switch 16, the PCS, and the battery PACK share the evaporator 24 for heat exchange. When the outlet water temperature is less than t2, the cooling capacity is excessive, and the first switch 17, the second switch 16, and the PCS use the air-water heat exchanger 15 for heat dissipation; when the outlet water temperature is greater than t2 and less than t1, both the first switch 17 and the second switch 16 are turned on.

[0025] A control method proposed for a liquid-cooled energy storage temperature control system: The optimal working temperature T5 of the battery PACK, such as 20°C - 30°C. When the energy storage system is not working, when it is detected that the ambient temperature is higher than T5, the refrigeration system starts, and the internal heat dissipation system of the battery starts to reduce the temperature of the battery PACK to T5; when it is detected that the ambient temperature is lower than T5, the PTC starts, and the internal heating system of the battery starts to raise the temperature of the battery PACK to T5; when the energy storage system is working, the refrigeration system is turned on, the battery PACK heat dissipation system and the PCS heat dissipation system are turned on, and the temperature inside the battery PACK is maintained at T5, such as 20°C - 30°C, and the PCS temperature is at T3, such as 80°C - 95°C.

[0026] In this solution, the battery PACK heat dissipation system and the PCS heat dissipation system share a set of refrigeration system. Among them, the fan 14 simultaneously enhances the heat exchange efficiency of the air-water heat exchanger 15 and the condenser 21, saving the usage of components. The heat exchange of the air-water heat exchanger 15 does not consume the cooling capacity of the compressor 23, reducing the system energy consumption. In the traditional air-cooled PCS heat dissipation, the common design is forward air intake and rear air outlet. This method cannot meet the customer's placement requirement of "back-to-back" for the equipment, and the heat dissipation effect is limited. Therefore, the liquid-cooled heat dissipation method is adopted to improve the heat dissipation effect. The forward air intake and upper air outlet design can be used to integrate the PCS and the battery PACK water chiller into one, meeting the "back-to-back" requirement of the equipment.

[0027] There are differences in the optimal operating temperatures of the PCS and the battery PACK. The optimal operating temperature of the battery PACK is T5 (20°C - 30°C), and the optimal operating temperature of the PCS power device is T3 (80°C - 95°C). In the traditional integrated method with one-way water outlet, the water outlet temperature is low, condensation is likely to occur on the PCS side, and the PCS cannot operate at the optimal temperature. The traditional two-way water outlet method requires two compressors 23, and the device design layout is complex. Moreover, in the traditional integrated method, the cooling capacity of the compressor 23 needs to be distributed to the PCS and the battery PACK, reducing the overall energy efficiency. In summary, the present invention solves the problems of complex traditional layout, many components, low water outlet temperature, and low energy efficiency.

[0028] As described above, the above are only the preferred specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution of the present invention and its inventive concept, makes equivalent substitutions or changes, and should be covered by the protection scope of the present invention.

Claims

1. A liquid-cooled energy storage temperature control system, characterized in that, It includes a PCS cooling system (1), a refrigerant circulation system (2), and a battery PACK cooling system (3). The PCS cooling system (1) is connected to the refrigerant circulation system (2) through the battery PACK cooling system (3). The PCS cooling system (1) includes a PCS (11), a first water pump (12), a first valve (13), a fan (14), and a water-air heat exchanger (15). The refrigerant circulation system (2) includes a condenser (21), an expansion valve (22), a compressor (23), and an evaporator (24). The battery PACK cooling system (3) includes a heater (31), a second valve (32), a water storage tank (33), a second water pump (34), a third valve (35), and a battery PACK (36).

2. The liquid-cooled energy storage temperature control system according to claim 1, wherein The PCS cooling system (1) further includes a first switch (17) and a second switch (16). The first switch (17) and the second switch (16) control the pipeline to be connected to the evaporator (24).

3. The liquid-cooled energy storage temperature control system according to claim 1, characterized in that The first water pump (12) is respectively connected to the first valve (13) and the water-air heat exchanger (15) through pipelines. The water-air heat exchanger (15) is used in cooperation with the fan (14). The first valve (13) is connected to the second valve (32) through a pipeline.

4. The liquid-cooled energy storage temperature control system according to claim 1, characterized in that, The second valve (32) is respectively connected to the heater (31) and the water storage tank (33) through pipelines. The water storage tank (33) is connected to the second water pump (34). The battery PACK (36) is respectively connected to the second water pump (34) and the third valve (35) through pipelines.

5. The liquid cooling energy storage temperature control system according to claim 1, wherein The evaporator (24) is respectively connected to the third valve (35), the expansion valve (22), and the compressor (23) through pipelines. The compressor (23) is connected to the expansion valve (22) through the condenser (21).

6. A control method proposed for the liquid-cooled energy storage temperature control system described in any one of claims 1-5, characterized in that, It includes the following steps: S1. The optimal operating temperature of the battery PACK is T5. When the energy storage system is not working and the detected ambient temperature is higher than T5, the refrigeration system starts, and the internal battery heat dissipation system starts to reduce the temperature of the battery PACK to T5. S2. When the detected ambient temperature is lower than T5, the PTC starts, and the internal battery heating system starts to raise the temperature of the battery PACK to T5. S3. When the energy storage system is working, turn on the refrigeration system, turn on the battery PACK heat dissipation system and the PCS heat dissipation system to keep the temperature inside the battery PACK at T5 and the temperature of the PCS at T3.

7. The control method according to claim 6, wherein, The temperature range of T5 is between 20°C and 30°C, and the temperature range of T3 is between 80°C and 95°C.

8. The control method according to claim 6, characterized in that, The control method is as follows: Perform temperature control by turning on the second switch (16). Perform temperature control by turning on the first switch (17). Perform temperature control by turning on the second switch (16) and the first switch (17) simultaneously.

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