Battery pack cooling system and electric vehicle

Abstract

The utility model discloses a battery pack cooling system and electromobile, battery pack cooling system includes refrigeration branch, first liquid cooling branch, second liquid cooling branch, ambient temperature sensor and controller, refrigeration branch includes compressor, first liquid cooling branch is coupled with refrigeration branch and carries out heat exchange with refrigeration branch, and second liquid cooling branch is coupled with refrigeration branch and carries out heat exchange with ambient temperature sensor. The first liquid cooling branch exchanges heat with the battery pack, the second liquid cooling branch exchanges heat with the battery pack, the environment temperature sensor is arranged on the compressor and used for collecting the environment temperature of the compressor, and the controller is configured to control the second liquid cooling branch to be started when the environment temperature of the compressor is lower than the starting temperature of the compressor. The cooling liquid in the second liquid cooling branch flows through the cooling pipe in the battery pack and exchanges heat with the battery pack, so that the battery pack is cooled, the problem that the compressor cannot be started when the environment temperature of the compressor is lower than the starting temperature of the compressor is avoided, the use performance of the battery pack is improved, the service life of the battery pack is prolonged, and the use safety of the battery pack is improved.

Description

Technical Field

[0001] The utility model relates to the battery pack cooling technology, in particular to a battery pack cooling system and an electric vehicle. Background Art

[0002] An electric vehicle refers to a vehicle powered by an on-vehicle battery pack and driven by an electric motor.

[0003] During the operation of the battery pack, a large amount of heat will be generated. Currently, the cooling method of the battery pack is usually compression refrigeration. However, when the compressor is below its starting temperature, the compressor cannot start, which will cause the heat of the battery pack to not dissipate, resulting in a temperature rise beyond the appropriate temperature range, thereby affecting the service performance and service life of the battery pack, and even posing a safety hazard. Summary of the Utility Model

[0004] The utility model provides a battery pack cooling system and an electric vehicle, which can avoid the problem that the compressor cannot start when the ambient temperature of the compressor is lower than the starting temperature of the compressor, and improve the service performance, service life and use safety of the battery pack.

[0005] In a first aspect, the utility model provides a battery pack cooling system, comprising:

[0006] A refrigeration branch, the refrigeration branch comprising a compressor;

[0007] A first liquid cooling branch, the first liquid cooling branch being coupled to the refrigeration branch and exchanging heat with the refrigeration branch, and the first liquid cooling branch exchanging heat with the battery pack;

[0008] A second liquid cooling branch, the second liquid cooling branch exchanging heat with the battery pack;

[0009] An ambient temperature sensor, the ambient temperature sensor being disposed on the compressor for collecting the ambient temperature of the compressor;

[0010] A controller, the ambient temperature sensor, the refrigeration branch and the second liquid cooling branch are all connected to the controller;

[0011] The controller is configured to control the start of the second liquid cooling branch when the ambient temperature of the compressor is lower than the starting temperature of the compressor.

[0012] Optionally, the battery pack cooling system further includes a heat exchanger. The refrigeration branch includes a compressor and an electromagnetic expansion valve. The liquid outlet of the compressor is communicated with the liquid inlet of the electromagnetic expansion valve. The liquid outlet of the electromagnetic expansion valve is communicated with the refrigerant inlet of the heat exchanger. The refrigerant outlet of the heat exchanger is communicated with the gas inlet of the compressor. The first liquid cooling branch is connected between the coolant inlet and the coolant outlet of the heat exchanger. Both the compressor and the electromagnetic expansion valve are connected to the controller.

[0013] Optionally, the battery pack cooling system further includes a heat exchanger. The first liquid cooling branch includes a circulation pump.

[0014] The coolant outlet of the heat exchanger is communicated with the liquid inlet of the battery pack. The liquid outlet of the battery pack is communicated with the liquid inlet of the circulation pump. The liquid outlet of the circulation pump is communicated with the coolant inlet of the heat exchanger. The circulation pump is connected to the controller.

[0015] Optionally, the second liquid cooling branch includes a radiator and a circulation pump.

[0016] The liquid inlet of the radiator is communicated with the liquid outlet of the battery pack. The liquid outlet of the radiator is communicated with the liquid inlet of the circulation pump. The liquid outlet of the circulation pump is communicated with the liquid inlet of the battery pack. The circulation pump is connected to the controller.

[0017] Optionally, the battery pack cooling system includes a heat exchanger, a three-way valve, a circulation pump and a radiator.

[0018] The coolant outlet of the heat exchanger is communicated with the liquid inlet of the battery pack. The liquid outlet of the battery pack is communicated with the first liquid inlet of the three-way valve. The liquid outlet of the three-way valve is communicated with the liquid inlet of the circulation pump. The liquid outlet of the circulation pump is communicated with the coolant inlet of the heat exchanger. A first liquid cooling branch is formed between the coolant inlet and the coolant outlet of the heat exchanger.

[0019] The coolant outlet of the heat exchanger is communicated with the liquid inlet of the battery pack. The liquid outlet of the battery pack is communicated with the liquid inlet of the radiator. The liquid outlet of the radiator is communicated with the second liquid inlet of the three-way valve. The liquid outlet of the three-way valve is communicated with the liquid inlet of the circulation pump. The liquid outlet of the circulation pump is communicated with the coolant inlet of the heat exchanger. A second liquid cooling branch is formed between the coolant inlet and the coolant outlet of the heat exchanger.

[0020] Both the three-way valve and the circulation pump are connected to the controller.

[0021] Optionally, the battery pack cooling system further includes a coolant temperature sensor disposed on the pipeline of the first liquid cooling branch, and the coolant temperature sensor is connected to the controller.

[0022] Optionally, the battery pack cooling system further includes a cooling fan disposed on one side of the radiator, and the cooling fan is connected to the controller.

[0023] Optionally, the battery pack cooling system further includes a heater and a battery temperature sensor;

[0024] The heater is connected in the first liquid cooling branch, and the battery temperature sensor is disposed on the battery pack for collecting the temperature of the battery pack. Both the heater and the battery temperature sensor are connected to the controller.

[0025] Optionally, the controller is a battery management system, and the battery management system is connected to the vehicle control system.

[0026] In a first aspect, the present invention further provides an electric vehicle including the battery pack cooling system provided in the first aspect of the present invention.

[0027] The battery pack cooling system provided by the present invention includes a refrigeration branch, a first liquid cooling branch, a second liquid cooling branch, an ambient temperature sensor, and a controller. The refrigeration branch includes a compressor. The first liquid cooling branch is coupled to the refrigeration branch for heat exchange with the refrigeration branch, and the first liquid cooling branch exchanges heat with the battery pack. The second liquid cooling branch exchanges heat with the battery pack. The ambient temperature sensor is disposed on the compressor for collecting the ambient temperature of the compressor. The ambient temperature sensor, the refrigeration branch, and the second liquid cooling branch are all connected to the controller. The controller is configured to control the start of the second liquid cooling branch when the ambient temperature of the compressor is lower than the start temperature of the compressor. The coolant in the second liquid cooling branch flows through the cooling pipe in the battery pack to exchange heat with the battery pack, achieving the cooling of the battery pack, and avoiding the problem that when the ambient temperature of the compressor is lower than the start temperature of the compressor, the compressor cannot start, the refrigeration branch cannot refrigerate, the coolant in the first liquid cooling loop cannot be cooled, and the heat exchange efficiency between the first liquid cooling loop and the battery pack is low, resulting in too high a temperature of the battery pack, affecting the service performance and service life of the battery pack, and improving the service performance, service life, and use safety of the battery pack. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The present invention will be further described in detail below with reference to the drawings and embodiments.

[0029] Figure 1 is a schematic structural diagram of a battery pack cooling system provided by the present invention;

[0030] Figure 2Schematic diagram of another battery pack cooling system provided by the present utility model;

[0031] Figure 3 Logic diagram of a control method for a battery pack cooling system provided by the present utility model. Detailed implementation manners

[0032] To make the technical problems solved, the technical solutions adopted, and the technical effects achieved by the present utility model clearer, the technical solutions of the embodiments of the present utility model will be further described in detail below with reference to the drawings. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all of the embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those skilled in the art without making creative efforts belong to the scope of protection of the present utility model.

[0033] In the description of the present utility model, unless otherwise clearly defined and limited, the terms "connected", "connected to", and "fixed" shall be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or integrated; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the internal communication of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood according to specific situations.

[0034] In the present utility model, unless otherwise clearly defined and limited, the first feature being "above" or "below" the second feature may include the direct contact between the first and second features, or may include the situation where the first and second features are not in direct contact but in contact through other features between them. Moreover, the first feature being "above", "above the upper side", and "on the upper surface" of the second feature includes the first feature being directly above and obliquely above the second feature, or simply indicating that the horizontal height of the first feature is higher than that of the second feature. The first feature being "below", "below the lower side", and "on the lower surface" of the second feature includes the first feature being directly below and obliquely below the second feature, or simply indicating that the horizontal height of the first feature is lower than that of the second feature. In addition, the terms "first" and "second" are only used for distinction in description and do not have special meanings.

[0035] Figure 1 Schematic diagram of a battery pack cooling system provided by the present utility model, as Figure 1 shown, the battery pack cooling system includes:

[0036] The refrigeration branch 110, and the refrigeration branch 110 includes a compressor 111. The refrigeration branch 110 is a closed pipeline system responsible for transferring refrigerant, including the path through which the refrigerant flows, connecting pipes, and various auxiliary devices. The compressor 111 raises the refrigerant from low pressure to high pressure, makes the refrigerant circulate continuously, and exchanges heat with the first liquid cooling branch to provide a cold source for the first liquid cooling branch.

[0037] The first liquid cooling branch 120, the first liquid cooling branch 120 is coupled to the refrigeration branch 110 and exchanges heat with the refrigeration branch 110. The first liquid cooling branch 120 exchanges heat with the battery pack and is used to cool the battery pack. Exemplarily, a coolant circulates inside the first liquid cooling branch 120. The first liquid cooling branch 120 and the refrigeration branch 110 can be coupled through a heat exchange device to realize the heat exchange between the coolant and the refrigerant and cool down the coolant inside the first liquid cooling branch 120. Exemplarily, the first liquid cooling branch 120 is connected to a cooling pipe arranged inside the battery pack to form a loop, and exchanges heat with the battery pack through the cooling pipe to cool down the battery pack.

[0038] The second liquid cooling branch 130, the second liquid cooling branch 130 exchanges heat with the battery pack. Exemplarily, a coolant circulates inside the second liquid cooling branch 130. The second liquid cooling branch 130 uses other methods besides compression refrigeration as a cold source to cool down the coolant in the second liquid cooling branch 130. For example, the second liquid cooling branch 130 exchanges heat with the air in the external environment to realize the cooling of the coolant in the second liquid cooling branch 130. The second liquid cooling branch 130 is connected to a cooling pipe arranged inside the battery pack to form a loop, and exchanges heat with the battery pack through the cooling pipe to cool down the battery pack. It should be noted that the coolants in the first liquid cooling branch 120 and the second liquid cooling branch 130 can be the same coolant or different coolants, and the embodiments of the present invention do not make any limitations here.

[0039] The ambient temperature sensor 140, the ambient temperature sensor 140 is arranged on the compressor 111 and is used to collect the ambient temperature of the compressor 111.

[0040] The controller 150, the ambient temperature sensor 140, the refrigeration branch 110, and the second liquid cooling branch 130 are all connected to the controller 150.

[0041] The controller 150 is configured to control the start of the second liquid cooling branch 130 when the ambient temperature of the compressor 111 is lower than the start temperature of the compressor 111.

[0042] Exemplarily, during the operation of an electric vehicle, when it is necessary to cool the battery pack, the ambient temperature sensor 140 collects the ambient temperature where the compressor 111 is located in real time and uploads it to the controller 150. The controller 150 compares the ambient temperature uploaded by the ambient temperature sensor 140 with the starting temperature of the compressor 111. When the ambient temperature of the compressor 111 is higher than or equal to the starting temperature of the compressor 111, the controller 150 controls the compressor 111 and the first liquid cooling branch 120 to start, and the refrigeration branch 110 starts to refrigerate. The first liquid cooling branch 120 exchanges heat with the refrigeration branch 110 to cool the coolant in the first liquid cooling branch 120. The coolant in the first liquid cooling branch 120 flows through the cooling pipes in the battery pack and exchanges heat with the battery pack to achieve cooling of the battery pack. When the ambient temperature of the compressor 111 is lower than the starting temperature of the compressor 111, the second liquid cooling branch 130 is controlled to start. The coolant in the second liquid cooling branch 130 flows through the cooling pipes in the battery pack and exchanges heat with the battery pack to achieve cooling of the battery pack, avoiding the problem that when the ambient temperature of the compressor 111 is lower than the starting temperature of the compressor 111, the compressor 111 cannot start, the refrigeration branch 110 cannot refrigerate, the coolant in the first liquid cooling loop 120 cannot be cooled, and the heat exchange efficiency between the first liquid cooling loop 120 and the battery pack is low, resulting in too high a temperature of the battery pack and affecting the service performance and service life of the battery pack. This improves the service performance and service life of the battery pack and enhances the use safety of the battery pack.

[0043] The battery pack cooling system provided by the embodiment of the present utility model includes a refrigeration branch, a first liquid cooling branch, a second liquid cooling branch, an ambient temperature sensor and a controller. The refrigeration branch includes a compressor. The first liquid cooling branch is coupled to the refrigeration branch for heat exchange. The first liquid cooling branch exchanges heat with the battery pack. The second liquid cooling branch exchanges heat with the battery pack. The ambient temperature sensor is disposed on the compressor for collecting the ambient temperature of the compressor. The ambient temperature sensor, the refrigeration branch and the second liquid cooling branch are all connected to the controller. The controller is configured to control the compressor and the first liquid cooling branch to start when the ambient temperature of the compressor is higher than or equal to the starting temperature of the compressor. The refrigeration branch starts to refrigerate. The first liquid cooling branch exchanges heat with the refrigeration branch to cool down the coolant in the first liquid cooling branch. The coolant in the first liquid cooling branch flows through the cooling pipes in the battery pack to exchange heat with the battery pack to achieve cooling of the battery pack. And when the ambient temperature of the compressor is lower than the starting temperature of the compressor, control the second liquid cooling branch to start. The coolant in the second liquid cooling branch flows through the cooling pipes in the battery pack to exchange heat with the battery pack to achieve cooling of the battery pack, avoiding the problem that when the ambient temperature of the compressor is lower than the starting temperature of the compressor, the compressor cannot start, the refrigeration branch cannot refrigerate, the coolant in the first liquid cooling loop cannot be cooled down, and the heat exchange efficiency between the first liquid cooling loop and the battery pack is low, resulting in too high temperature of the battery pack and affecting the service performance and service life of the battery pack, and improving the service performance, service life and use safety of the battery pack.

[0044] In some embodiments of the present utility model, as Figure 1 shown, the battery pack cooling system further includes a heat exchanger 160. The refrigeration branch 110 includes a compressor 111 and an electromagnetic expansion valve 112. The liquid outlet of the compressor 111 is communicated with the liquid inlet of the electromagnetic expansion valve 112. The liquid outlet of the electromagnetic expansion valve 112 is communicated with the refrigerant inlet of the heat exchanger 160. The refrigerant outlet of the heat exchanger 160 is communicated with the air inlet of the compressor 111. The first liquid cooling branch 120 is connected between the coolant inlet and the coolant outlet of the heat exchanger 160. Both the compressor 111 and the electromagnetic expansion valve 112 are connected to the controller 150.

[0045] Exemplarily, the working process of the refrigeration branch 110 is as follows: The controller 150 controls the compressor 111 to extract the low-temperature and low-pressure gaseous refrigerant from the heat exchanger 160, compress the gaseous refrigerant to obtain the low-temperature liquid refrigerant, and send the low-temperature liquid refrigerant into the electromagnetic expansion valve 112. The electromagnetic expansion valve 112 can adjust the valve opening under the control of the controller 150, thereby controlling the flow rate of the output gaseous refrigerant. After the flow rate of the low-temperature liquid refrigerant is adjusted by the electromagnetic expansion valve 112, it is sent into the heat exchanger 160, where it exchanges heat with the coolant in the first liquid cooling branch 120 to cool down the coolant in the first liquid cooling branch 120. During the heat exchange process, the liquid refrigerant is vaporized, and the gaseous refrigerant is extracted by the compressor 111 again, and this cycle repeats.

[0046] In some embodiments of the present invention, as Figure 1 shown, the first liquid cooling branch 120 includes a circulation pump 121. The coolant outlet of the heat exchanger 160 is communicated with the liquid inlet of the battery pack, the liquid outlet of the battery pack is communicated with the liquid inlet of the circulation pump 121, the liquid outlet of the circulation pump 121 is communicated with the coolant inlet of the heat exchanger 160, and the circulation pump 121 is connected to the controller 150. When the ambient temperature of the compressor 111 is higher than or equal to the starting temperature of the compressor 111, the controller 150 controls the compressor 111 to start. When the refrigeration branch 110 can refrigerate, the controller 150 controls the circulation pump 121 to start. The coolant in the first liquid cooling branch 120 circulates between the circulation pump 121, the heat exchanger 160 and the battery pack. The coolant in the first liquid cooling branch 120 exchanges heat with the refrigerant in the refrigeration branch 110 in the heat exchanger 160 to cool down the coolant in the first liquid cooling branch 120. The coolant in the first liquid cooling branch 120 flows through the cooling pipes in the battery pack and exchanges heat with the battery pack to cool down the battery pack, ensuring the service performance and service life of the battery pack and improving the use safety of the battery pack.

[0047] In some embodiments of the present invention, as Figure 1 shown, the second liquid cooling branch 130 includes a radiator 131 and a circulation pump 132. The liquid inlet of the radiator 131 is communicated with the liquid outlet of the battery pack, the liquid outlet of the radiator 131 is communicated with the liquid inlet of the circulation pump 132, the liquid outlet of the circulation pump 132 is communicated with the liquid inlet of the battery pack, and the circulation pump 132 is connected to the controller 150. When the ambient temperature of the compressor 111 is lower than the starting temperature of the compressor 111, the controller 150 controls the circulation pump 132 to start. The coolant in the second liquid cooling branch 130 flows through the radiator 131 to exchange heat with the external environment to achieve cooling. The cooled coolant flows through the cooling pipes in the battery pack and exchanges heat with the battery pack to cool down the battery pack, and then is extracted by the circulation pump 132 again and sent into the radiator, and this cycle repeats.

[0048] In some embodiments of the present utility model, such as Figure 1 shown, the battery pack cooling system further includes a cooling fan 133. The cooling fan 133 is disposed on one side of the radiator 131, and the cooling fan 133 is connected to the controller 150. When starting the circulation pump 132, the controller 150 controls the start of the cooling fan 133 to accelerate the air circulation speed near the radiator 131, thereby improving the heat dissipation efficiency of the radiator 131.

[0049] In some embodiments of the present utility model, such as Figure 1 shown, the battery pack cooling system further includes a coolant temperature sensor 122. The coolant temperature sensor 122 is disposed on the pipeline of the first liquid cooling branch 120, and the coolant temperature sensor 122 is connected to the controller 150, and is used to collect the temperature of the coolant in the pipeline of the first liquid cooling branch 120 and upload it to the controller 150. The controller 150 adjusts the opening degree of the electromagnetic expansion valve 112 based on the collected coolant temperature feedback, controls the refrigerant flow rate in the refrigeration branch 110, and thereby realizes the feedback control of the temperature of the coolant in the first liquid cooling branch 120 to maintain it within a set temperature range.

[0050] In some embodiments of the present utility model, such as Figure 1 shown, the battery pack cooling system further includes a heater 123 and a battery temperature sensor 124. The heater 123 is connected in the first liquid cooling branch 120, and the battery temperature sensor 124 is disposed on the battery pack. Exemplarily, it can be disposed inside or on the surface of the battery pack, and is used to collect the temperature of the battery pack. Both the heater 123 and the battery temperature sensor 124 are connected to the controller 150. Exemplarily, the battery temperature sensor 124 collects the temperature of the battery pack and uploads it to the controller 150. The controller 150 compares the collected temperature of the battery pack with a preset temperature. When the collected temperature of the battery pack is lower than the preset temperature, the controller 150 controls the refrigeration branch 110 and the second liquid cooling branch 130 to maintain a non-operating state, and controls the start of the first liquid cooling branch 120 and the heater 123. The refrigeration branch 110 and the second liquid cooling branch 130 stop working, and the coolant flowing through the heater 123 is heated. When the heated coolant flows through the battery pack, the battery pack is heated, avoiding the problem that the battery pack temperature is too low and the discharge performance decreases.

[0051] Figure 2 FIG. is a schematic structural diagram of another battery pack cooling system provided by the present utility model. In this embodiment, on the basis of the foregoing embodiment, a three-way valve is used to connect the first liquid cooling branch and the second liquid cooling branch, so as to realize the reuse of a circulation pump for the first liquid cooling branch and the second liquid cooling branch, reducing the system cost. Such as Figure 2 shown, the battery pack cooling system includes:

[0052] The refrigeration branch 110, and the refrigeration branch 110 includes a compressor 111.

[0053] The first liquid cooling branch 120, which is coupled to the refrigeration branch 110 and exchanges heat with the refrigeration branch 110. The first liquid cooling branch 120 exchanges heat with the battery pack and is used to cool the battery pack.

[0054] The second liquid cooling branch 130, which exchanges heat with the battery pack.

[0055] The ambient temperature sensor 140, which is disposed on the compressor 111 and is used to collect the ambient temperature of the compressor 111.

[0056] The controller 150, to which the ambient temperature sensor 140, the refrigeration branch 110, and the second liquid cooling branch 130 are all connected.

[0057] The controller 150 is configured to control the activation of the second liquid cooling branch 130 when the ambient temperature of the compressor 111 is lower than the starting temperature of the compressor 111.

[0058] Exemplarily, the battery pack cooling system includes a heat exchanger 160, a three-way valve 170, a circulation pump 180, and a radiator 131. The coolant outlet of the heat exchanger 160 is communicated with the liquid inlet of the battery pack. The liquid outlet of the battery pack is communicated with the first liquid inlet of the three-way valve 170. The liquid outlet of the three-way valve 170 is communicated with the liquid inlet of the circulation pump 180. The liquid outlet of the circulation pump 180 is communicated with the coolant inlet of the heat exchanger 160. Thus, a first liquid cooling branch 120 is formed between the coolant inlet of the heat exchanger 160 and the coolant outlet of the heat exchanger 160.

[0059] The coolant outlet of the heat exchanger 160 is communicated with the liquid inlet of the battery pack. The liquid outlet of the battery pack is communicated with the liquid inlet of the radiator 131. The liquid outlet of the radiator 131 is communicated with the second liquid inlet of the three-way valve 170. The liquid outlet of the three-way valve 170 is communicated with the liquid inlet of the circulation pump 180. The liquid outlet of the circulation pump 180 is communicated with the coolant inlet of the heat exchanger 160. A second liquid cooling branch 130 is formed between the coolant inlet of the heat exchanger 160 and the coolant outlet of the heat exchanger 160.

[0060] Both the three-way valve 170 and the circulation pump 180 are connected to the controller 150.

[0061] Exemplarily, when the ambient temperature of the compressor 111 is higher than or equal to the starting temperature of the compressor 111, the controller 150 controls the compressor 111 and the circulation pump 180 to start, controls the first liquid inlet of the three-way valve 170 to open, and the second liquid inlet to close. The coolant is driven by the circulation pump 180 and sent into the heat exchanger 160, where it exchanges heat with the refrigerant in the refrigeration branch 110. The temperature of the coolant drops, and then it is sent into the battery pack to cool the battery pack. The coolant flowing through the battery pack flows into the first liquid inlet of the three-way valve 170, flows out from the liquid outlet of the three-way valve 170, and is sent back into the heat exchanger 160 by the circulation pump 180 again, and so on in a cycle.

[0062] When the ambient temperature of the compressor 111 is lower than the starting temperature of the compressor 111, the compressor 111 cannot start. The controller 150 controls the circulation pump 180 to start, controls the second liquid inlet of the three-way valve 170 to open, and the first liquid inlet to close. The coolant is driven by the circulation pump 180 and flows through the radiator 131. The temperature of the coolant drops. The cooled coolant flows into the second liquid inlet of the three-way valve 170, flows out from the liquid outlet of the three-way valve 170, and is sent into the heat exchanger 160 by the circulation pump. Since the compressor 111 is not started, the coolant cannot exchange heat in the heat exchanger 160, and the temperature of the coolant hardly drops any more. The coolant after passing through the heat exchanger 160 is sent into the battery pack to cool the battery pack, and the coolant flowing through the battery pack is sent back into the radiator 131 again, and so on in a cycle.

[0063] In some embodiments of the present invention, as Figure 2 shown, the refrigeration branch 110 includes a compressor 111 and an electromagnetic expansion valve 112. The liquid outlet of the compressor 111 is communicated with the liquid inlet of the electromagnetic expansion valve 112. The liquid outlet of the electromagnetic expansion valve 112 is communicated with the refrigerant inlet of the heat exchanger 160. The refrigerant outlet of the heat exchanger 160 is communicated with the air inlet of the compressor 111. The first liquid cooling branch 120 is connected between the coolant inlet and the coolant outlet of the heat exchanger 160. Both the compressor 111 and the electromagnetic expansion valve 112 are connected to the controller 150.

[0064] In some embodiments of the present invention, as Figure 2 shown, the battery pack cooling system further includes a cooling fan 133. The cooling fan 133 is arranged on one side of the radiator 131, and the cooling fan 133 is connected to the controller 150. When starting the second liquid cooling branch 130, the controller 150 controls the cooling fan 133 to start, accelerating the air flow speed near the radiator 131, thereby improving the heat dissipation efficiency of the radiator 131.

[0065] In some embodiments of the present invention, as Figure 2As shown in the figure, the battery pack cooling system further includes a coolant temperature sensor 122. The coolant temperature sensor 122 is disposed on the pipeline of the first liquid cooling branch 120. The coolant temperature sensor 122 is connected to the controller 150 and is used to collect the temperature of the coolant in the pipeline of the first liquid cooling branch 120 and upload it to the controller 150. The controller 150 adjusts the opening degree of the electromagnetic expansion valve 112 based on the collected coolant temperature, controls the refrigerant flow rate in the refrigeration branch 110, and further realizes the feedback control of the temperature of the coolant in the first liquid cooling branch 120 to maintain it within the set temperature range.

[0066] In some embodiments of the present invention, as Figure 2 shown in the figure, the battery pack cooling system further includes a heater 123 and a battery temperature sensor 124. The heater 123 is connected between the liquid outlet of the battery pack and the first liquid inlet of the three-way valve 170. The battery temperature sensor 124 is disposed on the battery pack. Exemplarily, it can be disposed inside or on the surface of the battery pack and is used to collect the temperature of the battery pack. Both the heater 123 and the battery temperature sensor 124 are connected to the controller 150. Exemplarily, the battery temperature sensor 124 collects the temperature of the battery pack and uploads it to the controller 150. The controller 150 compares the collected temperature of the battery pack with the preset temperature. When the collected temperature of the battery pack is lower than the preset temperature, the controller 150 controls the refrigeration branch 110 and the second liquid cooling branch 130 to maintain a non-operating state, and controls the first liquid cooling branch 120 and the heater 123 to start, heating the coolant flowing through the heater 123. When the heated coolant flows through the battery pack, it heats the battery pack to avoid the problem of the battery pack temperature being too low and causing a decline in discharge performance.

[0067] In the above embodiments of the present invention, the controller 150 is a battery management system (Battery Management System, BMS), and the battery management system is connected to a vehicle control unit (Vehicle Control Unit, VCU). The existing battery pack cooling system is usually controlled by the vehicle control system, and the vehicle control system's response to the thermal management request of the battery pack is not flexible and rapid enough. In the embodiments of the present invention, the battery management system directly controls the battery pack cooling system, improving the response speed of the battery pack cooling system to the thermal management request.

[0068] The embodiments of the present invention further provide a control method for a battery pack cooling system. Figure 3 As shown in the logic diagram of a control method for a battery pack cooling system provided by the present invention, as Figure 3 shown in the figure, the control method of the battery pack cooling system is as follows:

[0069] During the operation of an electric vehicle, the temperature Ta of the battery pack is collected by a battery temperature sensor and uploaded to the controller. The controller compares the collected temperature Ta of the battery pack with the third set temperature T3 to determine whether the temperature Ta is less than the third set temperature T3. If the temperature Ta is less than the third set temperature T3, it is further determined whether the allowable discharge power Pmax of the battery pack under the current working condition is greater than the set power threshold Pset. If the allowable discharge power Pmax of the battery pack under the current working condition is not greater than the set power threshold Pset, the heating mode is entered. In the heating mode, the controller controls the refrigeration branch and the second liquid cooling branch not to work, controls the first liquid cooling branch to start, and the heater starts to heat the coolant in the first liquid cooling branch. When the heated coolant flows through the battery pack, the battery pack is heated. If the allowable discharge power Pmax of the battery pack under the current working condition is greater than the set power threshold Pset, the temperature equalization mode is entered. In the temperature equalization mode, the controller controls the refrigeration branch, the second liquid cooling branch and the heater not to work, controls the first liquid cooling branch to start, and uses the heat generated by the battery pack itself during operation to heat the battery pack, reducing energy consumption.

[0070] In the above steps, if the temperature Ta is not less than the third set temperature T3, it is further determined whether the temperature Ta is less than the second set temperature T2, where the second set temperature T2 is greater than the third set temperature T3. If the temperature Ta is less than the second set temperature T2, it is further determined whether the current charging current Ic is greater than the preset charging rate Iset. If the current charging current Ic is not greater than the preset charging rate Iset, the temperature equalization mode is entered. If the current charging current Ic is greater than the preset charging rate Iset, the first cooling mode is entered. In the first cooling mode, the controller controls the refrigeration branch, the first liquid cooling branch and the heater not to work, controls the second liquid cooling branch to start, and the second liquid cooling branch exchanges heat with the battery pack to cool the battery pack.

[0071] In the above steps, if the temperature Ta is not less than the second set temperature T2, it is further determined whether the temperature Ta is less than the first set temperature T1, where the first set temperature T1 is greater than the second set temperature T2. If the temperature Ta is less than the first set temperature T1, it is further determined whether the current charging current Ic is greater than the preset charging rate Iset. If the current charging current Ic is not greater than the preset charging rate Iset, the first cooling mode is entered. If the current charging current Ic is greater than the preset charging rate Iset, it is further determined whether the ambient temperature Tb collected by the ambient temperature sensor is less than the starting temperature Ts of the compressor. If the ambient temperature Tb is less than the starting temperature Ts of the compressor, the first cooling mode is entered. During the charging process, when the charging current Ic is greater than the preset charging rate Iset, the heat generation rate of the battery pack is relatively large, and cooling is advanced to reduce the temperature rise rate, which can shorten the charging time. If the ambient temperature Tb is not less than the starting temperature Ts of the compressor, the second cooling mode is entered. In the second cooling mode, the controller controls the refrigeration branch and the first liquid cooling branch to work, and the heater and the second cooling branch do not work. The first liquid cooling branch exchanges heat with the battery pack to cool down the battery pack.

[0072] In the above steps, if the temperature Ta is not less than the first set temperature T1, it is further determined whether the current state of charge SOC of the battery pack is greater than the preset state of charge SOCset. If the current state of charge SOC is greater than the preset state of charge SOCset, it is further determined whether the ambient temperature Tb collected by the ambient temperature sensor is less than the starting temperature Ts of the compressor. If the ambient temperature Tb is less than the starting temperature Ts of the compressor, the first cooling mode is entered. If the ambient temperature Tb is not less than the starting temperature Ts of the compressor, the second cooling mode is entered.

[0073] In the above steps, if the current state of charge SOC is not greater than the preset state of charge SOCset, the first cooling mode is entered. Since the power consumption of the compressor in the refrigeration branch is more than 10 times the rated power consumption of the second liquid cooling branch, when the vehicle is running and the state of charge SOC is relatively low, it is necessary to ensure a low power consumption mode, so the first cooling mode is switched to.

[0074] The present invention also provides an electric vehicle, including the battery pack cooling system provided in any of the foregoing embodiments of the present invention.

[0075] In the description herein, it should be understood that the orientation or positional relationships such as "upper", "lower", "left", "right", etc. are based on the orientation or positional relationships shown in the drawings, and are only for the convenience of description and simplifying the operation, 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 thus should not be construed as a limitation to the present invention.

[0076] In the description of this specification, the description with reference to the terms "an embodiment", "example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the utility model. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example.

[0077] In addition, it should be understood that although this specification is described according to 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 may also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

[0078] The technical principle of the present invention is described above in combination with specific embodiments. These descriptions are only for explaining the principle of the present invention and cannot be interpreted as limiting the protection scope of the present invention in any way. Based on the explanations here, technicians in this field can think of other specific implementation methods of the present invention without creative work, and these methods will fall within the protection scope of the present invention.

Claims

1. A battery pack cooling system, characterized in that: include: A refrigeration branch, wherein the refrigeration branch comprises a compressor; a first liquid cooling branch, the first liquid cooling branch being coupled to the refrigeration branch and performing heat exchange with the refrigeration branch, and the first liquid cooling branch exchanging heat with the battery pack; a second liquid cooling branch, wherein the second liquid cooling branch exchanges heat with the battery pack; An ambient temperature sensor is provided on the compressor and is used to collect the ambient temperature of the compressor; A controller, the ambient temperature sensor, the refrigeration branch and the second liquid cooling branch are all connected to the controller; The controller is configured to control the activation of the second liquid cooling branch when the ambient temperature of the compressor is lower than the activation temperature of the compressor.

2. The battery pack cooling system according to claim 1, characterized in that: The battery pack cooling system also includes a heat exchanger, and the refrigeration branch includes a compressor and an electromagnetic expansion valve. The liquid outlet of the compressor is connected to the liquid inlet of the electromagnetic expansion valve, and the liquid outlet of the electromagnetic expansion valve is connected to the refrigerant inlet of the heat exchanger. The refrigerant outlet of the heat exchanger is connected to the air inlet of the compressor. The first liquid cooling branch is connected between the coolant inlet and the coolant outlet of the heat exchanger, and the compressor and the electromagnetic expansion valve are both connected to the controller.

3. The battery pack cooling system according to claim 1, characterized in that: The battery pack cooling system further includes a heat exchanger, and the first liquid cooling branch includes a circulation pump; The coolant outlet of the heat exchanger is connected to the liquid inlet of the battery pack, the liquid outlet of the battery pack is connected to the liquid inlet of the circulation pump, the liquid outlet of the circulation pump is connected to the coolant inlet of the heat exchanger, and the circulation pump is connected to the controller.

4. The battery pack cooling system according to claim 1, characterized in that: The second liquid cooling branch includes a radiator and a circulation pump; The liquid inlet of the radiator is communicated with the liquid outlet of the battery pack, the liquid outlet of the radiator is communicated with the liquid inlet of the circulation pump, the liquid outlet of the circulation pump is communicated with the liquid inlet of the battery pack, and the circulation pump is connected to the controller.

5. The battery pack cooling system according to claim 1, characterized in that: The battery pack cooling system includes a heat exchanger, a three-way valve, a circulation pump and a radiator; The coolant outlet of the heat exchanger is communicated with the liquid inlet of the battery pack, the liquid outlet of the battery pack is communicated with the first liquid inlet of the three-way valve, the liquid outlet of the three-way valve is communicated with the liquid inlet of the circulation pump, the liquid outlet of the circulation pump is communicated with the coolant inlet of the heat exchanger, and a first liquid cooling branch is formed between the coolant inlet of the heat exchanger and the coolant outlet of the heat exchanger; The coolant outlet of the heat exchanger is communicated with the liquid inlet of the battery pack, the liquid outlet of the battery pack is communicated with the liquid inlet of the radiator, the liquid outlet of the radiator is communicated with the second liquid inlet of the three-way valve, the liquid outlet of the three-way valve is communicated with the liquid inlet of the circulation pump, the liquid outlet of the circulation pump is communicated with the coolant inlet of the heat exchanger, and a second liquid cooling branch is formed between the coolant inlet of the heat exchanger and the coolant outlet of the heat exchanger; The three-way valve and the circulation pump are both connected to the controller.

6. The battery pack cooling system according to any one of claims 1 to 5, characterized in that: The battery pack cooling system also includes a coolant temperature sensor, which is disposed on a pipeline of the first liquid cooling branch and is connected to the controller.

7. The battery pack cooling system according to claim 4 or 5, characterized in that: The battery pack cooling system also includes a cooling fan, which is disposed on one side of the radiator and is connected to the controller.

8. The battery pack cooling system according to any one of claims 1 to 5, characterized in that: The battery pack cooling system also includes a heater and a battery temperature sensor; The heater is connected in the first liquid cooling branch, the battery temperature sensor is arranged on the battery pack and is used to collect the temperature of the battery pack, and the heater and the battery temperature sensor are both connected to the controller.

9. The battery pack cooling system according to any one of claims 1 to 5, characterized in that: The controller is a battery management system, and the battery management system is connected to the vehicle control system.

10. An electric vehicle, characterized in that: Comprising a battery pack cooling system as described in any one of claims 1-9.

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