Energy storage cell temperature control system

Abstract

The utility model provides an energy storage battery cell temperature control system, which can better realize cold and hot temperature control on an energy storage battery cell, not only ensures uniform cooling and improves cooling efficiency, but also can prevent a battery cell cold plate from generating larger temperature fluctuation during heating operation. The air conditioner comprises a compressor, a condenser and a heat exchanger, the condenser is provided with a condensation fan, the heat exchanger comprises a first inlet, a second inlet, a first outlet and a second outlet, the first outlet is connected with an inlet of the compressor, and an outlet of the condenser is connected with the second inlet; the second outlet is connected with the primary throttling mechanism after passing through the one-way valve, the inlet of the cold plate is connected with a secondary throttling mechanism, the primary throttling mechanism is connected with the secondary throttling mechanism, the outlet of the cold plate is connected with the first inlet, and the outlet of the cold plate is connected with the second inlet. The output of the compressor after the refrigerant is compressed is divided into two paths after being connected with the control valve assembly, one path enters the condenser, and the other path is connected to a connecting pipeline between the one-way valve and the primary throttling mechanism.

Description

Technical Field

[0001] The utility model relates to the technical field of energy storage battery core temperature control, in particular to an energy storage battery core temperature control system. Background Art

[0002] In energy storage applications, current temperature control methods involve directly cooling or heating the energy storage cells by allowing refrigerant to flow directly into a cold plate. This involves cooling the cells by allowing the refrigerant to flow into the cold plate at the bottom of the cells, removing heat and cooling the cells. Alternatively, the cold plate is heated through a reverse Carnot cycle (heat pump operation). However, these cooling or heating temperature control methods have the following disadvantages:

[0003] 1. The battery cell cold plates are connected in parallel. During cooling operation, if the refrigerant enters the parallel battery cell cold plates together, the refrigerant entering each battery cell cold plate will be unevenly distributed. This will cause uneven cooling of each battery cell cold plate and low cooling efficiency, thus affecting the charging and discharging effect and life of the battery cell.

[0004] 2. The battery cold plate is covered with multiple energy storage batteries. In order to ensure that refrigerant liquid is evaporating in each flow channel of the battery cold plate, the refrigerant coming out of the battery cold plate must not be entirely in a gaseous state. If it is entirely in a gaseous state, it means that there is no liquid refrigerant in a part of the flow channel of the battery cold plate, that is, all the liquid refrigerant evaporates into gaseous refrigerant before leaving the battery cold plate. In this case, there will be a part of the flow channel where there is no liquid refrigerant to evaporate and absorb heat. The surface temperature of the battery cold plate in this area will be uneven, which will also lead to uneven cooling of the batteries arranged on the surface of the battery cold plate.

[0005] 3. During heating operation, if the conventional heat pump heating operation is used to heat the battery cell cold plate, the temperature control unit will have a defrosting action during heating operation, and the refrigerant entering the battery cell cold plate will have a hot and cold cycle, which will cause large temperature fluctuations in the battery cell cold plate. Summary of the Invention

[0006] In response to the above problems, the present invention provides an energy storage battery cell temperature control system, which can better achieve hot and cold temperature control of the energy storage battery cell, not only ensuring uniform cooling and improving cooling efficiency, but also avoiding large temperature fluctuations of the battery cell cold plate during heating operation.

[0007] The utility model adopts the following technical solution: a temperature control system for an energy storage battery cell, which includes a compressor, a condenser, and a heat exchanger. The condenser is equipped with a condensing fan. The heat exchanger includes a first inlet, a second inlet, a first outlet, and a second outlet. The first outlet is connected to the inlet of the compressor, and the outlet of the condenser is connected to the second inlet.

[0008] It also includes a one-way valve and a primary throttling mechanism. The second outlet is connected to the primary throttling mechanism after passing through the one-way valve. The inlet of the cold plate is connected to the secondary throttling mechanism. The primary throttling mechanism is connected to the secondary throttling mechanism. The outlet of the cold plate is connected to the first inlet. The output of the compressor after compressing the refrigerant is divided into two paths after being connected to the control valve assembly. One path enters the condenser, and the other path is connected to the connecting pipeline between the one-way valve and the primary throttling mechanism.

[0009] Furthermore, the control valve assembly includes a first solenoid valve and a second solenoid valve. The compressor divides the output of the compressed refrigerant into two paths, one path passes through the first solenoid valve and enters the condenser, and the other path passes through the second solenoid valve and is connected to the connecting pipeline between the one-way valve and the primary throttling mechanism.

[0010] Furthermore, the control valve assembly adopts a three-way valve, and the output of the refrigerant after the compressor is compressed is divided into two paths after being connected to the three-way valve. One path enters the condenser through one outlet of the three-way valve, and the other path passes through the other outlet of the three-way valve and is connected to the connecting pipeline between the one-way valve and the primary throttling mechanism;

[0011] Furthermore, the cold plates are provided with a plurality of blocks, and are connected in parallel with each other, the inlet of each cold plate is connected to the secondary throttling mechanism, and the outlet of the primary throttling mechanism is connected to the inlet of the secondary throttling mechanism;

[0012] Furthermore, a pressure sensor and a first temperature sensor are provided on the connecting pipeline between the cold plate and the heat exchanger, and a second temperature sensor is provided on the connecting pipeline between the heat exchanger and the compressor.

[0013] The beneficial effect of the present invention is that it can ensure that the refrigerant entering each cold plate is more uniform by adopting a two-stage throttling method of a primary throttling mechanism and a secondary throttling mechanism, thereby ensuring that the battery cells on the surface of the cold plate are cooled uniformly, and during heating operation, by allowing the high-temperature and high-pressure gaseous refrigerant to carry the heat generated by the compressor's own power consumption during operation, enter the cold plate to heat the cold plate. There is no phase change and heat absorption process of the refrigerant, so there is no defrosting process, which will not affect the temperature fluctuation during heating operation. The heating capacity is not affected by the external ambient temperature, which ensures the temperature stability of the cold plate during the heating process and the reliability of the compressor operation, and has good economic use value. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a connection diagram of the first embodiment of the present utility model;

[0015] Figure 2This is a connection diagram of the second embodiment of the present utility model. DETAILED DESCRIPTION

[0016] Example 1

[0017] like Figure 1 As shown, a temperature control system for an energy storage battery cell includes a compressor 1, a condenser 2, and a heat exchanger 3. The condenser 2 is equipped with a condensing fan 4. The heat exchanger 3 includes a first inlet, a second inlet, a first outlet, and a second outlet. The first outlet is connected to the inlet of the compressor 1, and the outlet of the condenser 2 is connected to the second inlet; it also includes a one-way valve 5 and a primary throttling mechanism 6. Several cold plates 7 are provided and connected in parallel with each other. The inlet of each cold plate 7 is connected to a secondary throttling mechanism 8, and the outlet of the primary throttling mechanism 6 is connected to the inlet of the secondary throttling mechanism 8; the second outlet is connected to the primary throttling mechanism 6 after passing through the one-way valve 5, and the outlet of the cold plate 7 is connected to the first inlet. The output of the refrigerant compressed by the compressor 1 is divided into two paths after being connected to the control valve assembly. One path enters the condenser 2, and the other path is connected to the connecting pipeline between the one-way valve 5 and the primary throttling mechanism 6.

[0018] The control valve assembly includes a first solenoid valve 9 and a second solenoid valve 10. The compressor 1 divides the output of the compressed refrigerant into two paths. One path enters the condenser 2 after passing through the first solenoid valve 9, and the other path passes through the second solenoid valve 10 and is connected to the connecting pipeline between the one-way valve 5 and the primary throttling mechanism 6.

[0019] A pressure sensor 11 and a first temperature sensor 12 are provided on the connecting pipeline between the cold plate 7 and the heat exchanger 3 , and a second temperature sensor 13 is provided on the connecting pipeline between the heat exchanger 3 and the compressor 1 .

[0020] Example 2

[0021] like Figure 2 As shown, the control valve assembly adopts a three-way valve 14. The compressor 1 divides the output of the compressed refrigerant into two paths after connecting to the three-way valve 14. One path enters the condenser 2 through one of the outlets of the three-way valve 14, and the other path passes through the other outlet of the three-way valve 14 and is connected to the connecting pipeline between the one-way valve 5 and the primary throttling mechanism 6.

[0022] By adopting the structures of Example 1 and Example 2, this patent also provides a temperature control method for an energy storage cell, including:

[0023] During cooling operation, the output of compressor 1 is divided into two paths. One path between compressor 1 and condenser 2 is connected, and the other path of compressor 1 output is closed. Then, compressor 1 compresses the gaseous refrigerant into a high-temperature and high-pressure gas and outputs it to condenser 2 for cooling. The gas then passes through heat exchanger 3, one-way valve 5, primary throttling mechanism 6, and corresponding secondary throttling mechanism 8 to enter the corresponding cold plate 7 for cooling. The refrigerant output from cold plate 7 then passes through heat exchanger 3 and returns to compressor 1 again, and continues to circulate to continuously cool the cold plate 7.

[0024] Specifically, during refrigeration operation, the following steps are included:

[0025] S1.1. In response to a cooling request, compressor 1 compresses the gaseous refrigerant into a high-temperature, high-pressure gas. The refrigerant then flows through the control valve assembly (i.e., first solenoid valve 9 is open and second solenoid valve 10 is closed; or, alternatively, three-way valve 14 opens one outlet connected to condenser 2 and closes the other outlet) into condenser 2 for cooling. Heat is removed by the air circulated by condensing fan 4 through condenser 2, and the refrigerant is cooled to a medium-temperature, high-pressure liquid.

[0026] S1.2. The medium-temperature, high-pressure liquid refrigerant passes through the heat exchanger 3 and the one-way valve 5, and undergoes preliminary throttling and pressure reduction through the primary throttling mechanism 6. At this point, the refrigerant pressure is higher than the refrigerant flash point, that is, the refrigerant exiting the primary throttling mechanism 6 is still medium-temperature, high-pressure liquid refrigerant. Because it is liquid refrigerant, this ensures that the refrigerant entering the secondary throttling mechanism 8 before each cold plate 7 is relatively uniform. Then, each channel of medium-temperature, high-pressure liquid refrigerant passes through the corresponding secondary throttling mechanism 8 to reduce the pressure below the refrigerant flash point, and the refrigerant becomes a low-temperature, low-pressure gas-liquid mixture. It evaporates and absorbs heat within the cold plate 7, thereby cooling the cold plate 7.

[0027] The primary throttling mechanism 6 is used to control the refrigerant flow rate and initial small pressure reduction entering the cold plate 7, and prevent the refrigerant from being depressurized to the flash point. The refrigerant exiting the primary throttling mechanism 6 is still a high-pressure liquid refrigerant, which ensures that the refrigerant entering the secondary throttling mechanism 8 of each cold plate 7 is evenly distributed. This solves the problem of even distribution of refrigerant entering each cold plate 7, and ensures the cooling uniformity of the cold plate 7.

[0028] S1.3. The refrigerant flowing out of the cold plate 7 exchanges heat with the medium-temperature, high-pressure liquid refrigerant coming out of the condenser 2 in the heat exchanger 3. The remaining unevaporated liquid refrigerant from the cold plate 7 continues to evaporate and absorb heat in the heat exchanger 3, cooling the liquid refrigerant coming out of the condenser 2 and simultaneously evaporating it into gaseous refrigerant. After the refrigerant has completely converted to gas, it returns to the compressor 1 and repeats step S1.1 to continue the cooling cycle.

[0029] During the entire refrigeration operation, in order to ensure the temperature uniformity of the entire surface of the cold plate 7, refrigerant liquid is evaporating in each flow channel in the cold plate 7. It is necessary to make the flow channels of the cold plate 7 all contain liquid refrigerant, that is, the refrigerant entering the cold plate 7 cannot be completely evaporated into gaseous refrigerant, and a small amount of liquid refrigerant must remain to flow out of the cold plate 7. If it is all gaseous, it means that there is a part of the flow channel in the cold plate 7 without liquid refrigerant, that is, all the liquid refrigerant is evaporated into gaseous refrigerant before leaving the cold plate 7. In this case, there will be a part of the flow channel without liquid refrigerant evaporation When absorbing heat, the surface temperature of the cold plate 7 in this area will be uneven, which will cause uneven cooling of the battery cells arranged on the surface of the cold plate 7. In order to avoid this situation, a small part of the refrigerant coming out of the cold plate 7 must be liquid. To this end, it is possible to judge whether the refrigerant coming out of the cold plate 7 contains some liquid based on the saturation temperature Ts of the refrigerant currently flowing out of the cold plate 7, and then control the opening size of the primary throttling mechanism 6 to adjust the flow rate of the refrigerant to ensure that the refrigerant coming out of the cold plate 7 contains a small part of liquid refrigerant, so as to ensure that the battery cells on the surface of the cold plate 7 are cooled evenly.

[0030] However, if liquid refrigerant directly enters the compressor 1, the compressor 1 will be damaged due to liquid hammer. In order to prevent some liquid refrigerant from entering the compressor 1, a heat exchanger 3 is set on the pipeline entering the compressor 1. At the same time, the medium-temperature refrigerant coming out of the condenser 2 also flows through the heat exchanger 3. The low-temperature gas-liquid mixed refrigerant exchanges heat with the medium-temperature refrigerant coming out of the condenser 2 in the heat exchanger 3. The medium-temperature refrigerant coming out of the condenser 2 is further cooled, which increases the supercooling of the refrigerant and improves the refrigeration efficiency. At the same time, the liquid refrigerant in the low-temperature and low-pressure refrigerant gas-liquid mixture flowing through the heat exchanger 3 absorbs heat and evaporates, and all becomes gaseous refrigerant. The gaseous refrigerant continues to exchange heat with the refrigerant entering the heat exchanger 3 in the heat exchanger 3. The low-temperature and low-pressure gaseous refrigerant absorbs heat and becomes superheated, and then enters the compressor 1, thereby ensuring the operating reliability of the compressor 1.

[0031] Furthermore, the pressure value P1 on the connecting pipe between the cold plate 7 and the heat exchanger 3 is obtained by the pressure sensor 11, and the saturation temperature Ts of the refrigerant currently flowing out of the cold plate 7 is obtained based on the pressure value P1. The method of obtaining the saturation temperature of the refrigerant by the pressure value is an existing method, and the corresponding saturation temperature can be obtained by directly comparing the pressure value.

[0032] If Ts<T1, the refrigerant currently flowing out of the cold plate 7 is in a superheated state, and the refrigerant flowing out of the cold plate 7 does not contain liquid refrigerant;

[0033] If Ts=T1 (actually, Ts≈T1 is sufficient), the refrigerant flowing out of the cold plate 7 is currently in a saturated state, and the refrigerant flowing out of the cold plate 7 contains liquid refrigerant;

[0034] Wherein, T1 is the temperature at the first inlet of the heat exchanger 3 collected by the first temperature sensor 12;

[0035] Furthermore, if the refrigerant flowing out of the cold plate 7 does not contain liquid refrigerant, the opening of the primary throttling mechanism 6 is increased to increase the refrigerant flow rate flowing into the cold plate 7, allowing more refrigerant to flow into the cold plate 7;

[0036] If T2-Ts is less than the set threshold, the opening of the primary throttling mechanism 6 is reduced to reduce the refrigerant flow into the cold plate 7. This ensures that all the remaining liquid refrigerant in the heat exchanger 3 evaporates into gas and then enters the compressor 1, ensuring the reliability of the compressor 1.

[0037] Wherein, T2 is the temperature at the first outlet of the heat exchanger 3 collected by the second temperature sensor 13;

[0038] During heating operation, the output of the compressor 1 is divided into two paths. One path of the pipeline between the compressor 1 and the condenser 2 is closed, and the other path of the compressor 1 output is opened. The compressor 1 compresses the gaseous refrigerant into a high-temperature and high-pressure gas and then flows to the primary throttling mechanism 6. Then, it passes through the corresponding secondary throttling mechanism 8 and enters the corresponding cold plate 7 for heating and temperature increase. Then, the refrigerant output from the cold plate 7 passes through the heat exchanger 3 and returns to the compressor 1 again, and continues to circulate to continuously heat and temperature increase the cold plate 7. During heating operation, the heat of the refrigerant comes from the working power consumption of the compressor 1 itself during operation. There is no phase change and heat absorption process of the refrigerant, so there is no defrosting. In this mode, the heating capacity is not affected by the external ambient temperature, which ensures that the cold plate 7 can be continuously heated and heated under various ambient temperature conditions, while ensuring the temperature stability of the cold plate 7 during the heating process and the reliability of the operation of the compressor 1.

[0039] Specifically, during heating operation, the following steps are included:

[0040] S2.1. In response to a heating request, the gaseous refrigerant enters compressor 1, where it is compressed and absorbs heat generated by the motor of compressor 1, becoming a high-temperature, high-pressure gas. The high-temperature, high-pressure gaseous refrigerant then flows through the control valve assembly (i.e., first solenoid valve 9 is closed and second solenoid valve 10 is open; or, alternatively, one outlet of three-way valve 14 connecting to condenser 2 is closed and the other outlet is open) into the connecting pipeline between check valve 5 and primary throttling mechanism 6. Because of the obstruction of check valve 5, the high-temperature, high-pressure gaseous refrigerant can only flow into primary throttling mechanism 6.

[0041] S2.2. The high-temperature, high-pressure gaseous refrigerant is depressurized by the primary throttling mechanism 6 and the secondary throttling mechanism 8 into a high-temperature, low-pressure gaseous refrigerant, which enters the cold plate 7 to heat the cold plate 7 and cool the refrigerant at the same time. Because the high-temperature, low-pressure gaseous refrigerant entering the cold plate 7 has a lower pressure and a lower saturation temperature, it is prevented from condensing into liquid in the cold plate 7 (which would damage the compressor 1 if the condensed liquid refrigerant enters the compressor 1). The high-temperature, low-pressure gaseous refrigerant only exchanges heat with the cold plate 7, heating the cold plate 7, while being cooled into a low-temperature, low-pressure refrigerant.

[0042] S2.3. After the low-temperature and low-pressure refrigerant flows out of the cold plate 7, it flows back to the compressor 1 through the heat exchanger 3 and repeats step S2.1 to continue the cycle of heating.

[0043] The utility model has the following technical effects:

[0044] A two-stage throttling mechanism is adopted. The primary throttling mechanism 6 mainly functions to adjust the flow rate and initially reduce the pressure. The refrigerant coming out of the primary throttling mechanism 6 is still liquid refrigerant. The secondary throttling mechanism 8 mainly functions to reduce the pressure. After throttling and reducing the pressure through the secondary throttling mechanism 8, the refrigerant becomes a low-pressure gas-liquid mixture and enters the cold plate 7. This can make the refrigerant entering each cold plate 7 more uniform. The secondary throttling mechanism 8 can adopt an existing throttling element with an adjustable opening, or a throttling element with a fixed opening.

[0045] In order to ensure that the battery cells arranged on the surface of the cold plate 7 are evenly cooled, the refrigerant flowing out of the cold plate 7 must contain a small amount of liquid refrigerant. By adjusting the opening of the primary throttling mechanism 6, this is ensured to contain a small amount of liquid refrigerant. At the same time, because the liquid refrigerant cannot directly enter the compressor 1, a heat exchanger 3 is used to achieve complete evaporation of the liquid refrigerant in the refrigerant flowing out of the cold plate 7, and the liquid refrigerant is superheated before entering the compressor 1, thereby ensuring the operational reliability of the compressor 1.

[0046] The low-pressure gaseous refrigerant carries the heat generated by the compressor 1 during operation and enters the cold plate 7 to heat the cold plate 7. There is no defrosting process, and the temperature fluctuation during heating operation will not be affected. It is also not affected by the external ambient temperature, and the heating capacity is continuously stable.

[0047] The direction of the arrow in the figure indicates the flow of the refrigerant.

[0048] In both the first and second embodiments, three cold plates are provided, and correspondingly, three secondary throttling mechanisms are also provided; the number of cold plates can be set according to actual conditions.

[0049] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the present invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the present invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the present invention is defined by the appended claims, not the foregoing description, and all variations within the meaning and range of equivalents of the claims are intended to be encompassed within the present invention. Any reference sign in a claim should not be construed as limiting the claim to which it relates.

[0050] In addition, it should be understood that although this specification is described in terms of implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

Claims

1. A temperature control system for an energy storage battery cell, comprising a compressor, a condenser, and a heat exchanger, wherein the condenser is equipped with a condensing fan, the heat exchanger comprises a first inlet, a second inlet, a first outlet, and a second outlet, the first outlet being connected to the inlet of the compressor, and the outlet of the condenser being connected to the second inlet; characterized in that: It also includes a one-way valve and a primary throttling mechanism. The second outlet is connected to the primary throttling mechanism after passing through the one-way valve. The inlet of the cold plate is connected to the secondary throttling mechanism. The primary throttling mechanism is connected to the secondary throttling mechanism. The outlet of the cold plate is connected to the first inlet. The output of the compressor after compressing the refrigerant is divided into two paths after being connected to the control valve assembly. One path enters the condenser, and the other path is connected to the connecting pipeline between the one-way valve and the primary throttling mechanism.

2. The energy storage battery core temperature control system according to claim 1, characterized in that: The control valve assembly includes a first solenoid valve and a second solenoid valve. The compressor divides the output of the compressed refrigerant into two paths, one path enters the condenser after passing through the first solenoid valve, and the other path passes through the second solenoid valve and is connected to the connecting pipeline between the one-way valve and the primary throttling mechanism.

3. The energy storage battery core temperature control system according to claim 1, characterized in that: The control valve assembly adopts a three-way valve, and the output of the refrigerant compressed by the compressor is divided into two paths after being connected to the three-way valve. One path enters the condenser through one of the outlets of the three-way valve, and the other path passes through the other outlet of the three-way valve and is connected to the connecting pipeline between the one-way valve and the primary throttling mechanism.

4. The energy storage battery core temperature control system according to claim 2 or 3, characterized in that: The cold plates are provided with a plurality of blocks and are connected in parallel with each other. The inlet of each cold plate is connected to the secondary throttling mechanism, and the outlet of the primary throttling mechanism is connected to the inlet of the secondary throttling mechanism.

5. The energy storage battery core temperature control system according to claim 2 or 3, characterized in that: A pressure sensor and a first temperature sensor are provided on the connecting pipeline between the cold plate and the heat exchanger, and a second temperature sensor is provided on the connecting pipeline between the heat exchanger and the compressor.

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