Battery direct cooling system, method, vehicle battery management system and vehicle

Abstract

The present invention provides a battery direct cooling system, method, vehicle battery management system and vehicle, the system includes: a direct cooling plate and a switching detection device, a flow channel and a liquid accumulation tank are arranged in the direct cooling plate; wherein, refrigerant flows in the flow channel, and two flow ports are arranged, namely a first flow port and a second flow port, one of the flow ports is selected as the inlet of the flow channel, and the other flow port is selected as the outlet of the flow channel; the liquid accumulation tank includes a first liquid accumulation tank and a second liquid accumulation tank, which are respectively arranged at the first flow port and the second flow port, and refrigerant is deposited, the liquid accumulation tank near the outlet is used to replenish the refrigerant in the flow channel, and the liquid accumulation tank near the inlet is used to receive the refrigerant flowing into the inlet, so that the refrigerant in the flow channel remains in a saturated state; if a trigger signal generated by the switching detection device is received, the outlet is switched to the inlet to allow the refrigerant to flow in the reverse direction. The present invention ensures the uniformity of heat exchange in the direct cooling system, avoids the phenomenon of drying out, and the reliability of heat exchange in the direct cooling system is high.

Description

Technical Field

[0001] The present invention relates to the technical field of battery direct cooling, and in particular to a battery direct cooling system, method, vehicle battery management system and vehicle. Background Art

[0002] Power batteries are the power source of new energy vehicles. On the one hand, in order to increase the vehicle's cruising range, the vehicle needs to arrange as many battery cells as possible in a certain space, so the space of the battery pack is very limited. The battery will generate a lot of heat during the operation of the vehicle and accumulate in a relatively small space over time; on the other hand, in order to shorten the charging time of electric vehicles to the greatest extent, the battery is charged at a high rate, causing the heat generated by the battery to soar sharply. If this heat cannot be dissipated in time, the battery temperature will be too high, greatly affecting the battery's power and life. In severe cases, there is also a risk of thermal runaway. Therefore, the battery needs to be cooled. In the relevant technology, the battery heat dissipation methods include air cooling, water cooling and direct cooling. Among them, air cooling heat dissipation is to achieve the effect of heat exchange cooling by flowing cold air through the surface of the battery. Water cooling heat dissipation is generally indirect heat dissipation. The heat generated by the battery is transferred to the cooling system through the cooling system, and then the heat is transferred to the refrigerant in the battery cooler through the battery cooler. Finally, the heat is dissipated to the air by the condenser. The two heat dissipation methods of air cooling and water cooling are less efficient, and direct cooling heat dissipation is direct heat exchange. That is, in the direct cooling system, the compressor drives the refrigerant to condense through the condenser first, and then enters the direct cooling plate after the expansion valve to directly dissipate the heat of the battery. The refrigerant heat exchange is phase change heat exchange, which has the advantages of high heat dissipation efficiency, strong heat exchange capacity and low cost. Therefore, battery direct cooling technology has been quickly put on the agenda.

[0003] However, the direct cooling system mainly utilizes the principle of latent heat of evaporation of refrigerant. The coolant evaporates in the direct cooling plate to quickly take away the heat from the battery and complete the cooling of the battery. On the one hand, the refrigerant must be in a saturated state in the direct cooling plate, but the size of the direct cooling plate is getting larger and larger. Uneven temperature and local drying are prone to occur during the heat exchange process, resulting in poor heat exchange efficiency and excessive temperature difference between battery packs. On the other hand, when the refrigerant enters the compressor, there is a problem of liquid hammer in the compressor due to insufficient superheat, which can easily damage the compressor.

[0004] Patent CN114784414A discloses a direct-cooling and liquid-cooling universal heat exchanger structure for new energy battery packs, which ensures the uniform temperature performance of the heat exchanger by setting up a complex and long flow channel. However, the flow channel structure of this solution has limitations and the improvement of the uniform temperature performance is limited. Patent CN114976350A provides a stamping plate structure of a direct-cooling and direct-heating heat exchanger for new energy battery packs, which uses a complex flow channel structure and a temperature plate to ensure the uniform temperature in the flow channel. However, this solution has high process requirements and the improvement of the uniform temperature performance is limited.

[0005] Therefore, how to improve the temperature uniformity performance of the direct cooling system and meet the superheat requirements of the refrigerant is a problem that needs to be solved urgently. Summary of the invention

[0006] In view of the above-mentioned shortcomings of the prior art, the present invention provides a battery direct cooling system, method, vehicle battery management system and vehicle to solve at least one of the above-mentioned technical problems.

[0007] In a first aspect, the present invention provides a battery direct cooling system, comprising: a direct cooling plate and a switching detection device, wherein a flow channel and a liquid accumulation groove are arranged in the direct cooling plate; wherein a refrigerant flows in the flow channel for absorbing heat generated by a battery pack, and the flow channel is provided with two flow ports, namely a first flow port and a second flow port, one of the flow ports is optionally used as an inlet for the refrigerant to flow into the flow channel, and the other flow port is optionally used as an outlet for the refrigerant to flow out of the flow channel; the liquid accumulation groove comprises a first liquid accumulation groove and a second liquid accumulation groove, which are respectively arranged at the first flow port and the second flow port and are deposited with the refrigerant, the liquid accumulation groove close to the outlet is used to replenish the refrigerant in the flow channel, and the liquid accumulation groove close to the inlet is used to receive the refrigerant flowing into the inlet so that the refrigerant in the flow channel remains in a saturated state; if a trigger signal generated by the switching detection device is received, the outlet is switched to the inlet to allow the refrigerant to flow in the reverse direction.

[0008] In one embodiment of the present invention, the switching detection device includes a first temperature sensor and a second temperature sensor, which are respectively arranged at the first circulation port and the second circulation port, the first temperature sensor is used to detect the first temperature of the refrigerant flowing through the first circulation port, and the second temperature sensor is used to detect the second temperature flowing through the second circulation port; wherein, if the outlet is set to the first circulation port, and the first temperature is higher than the preset first temperature threshold, it is determined that the refrigerant in the liquid accumulation tank located at the first circulation port is insufficient, and the first temperature sensor generates a first trigger signal to switch the outlet to the second circulation port; until the second temperature is higher than the preset first temperature threshold, the second trigger signal is generated by the second temperature sensor, and then the outlet is switched to the first circulation port, wherein the first trigger signal and the second trigger signal are respectively used as the trigger signals.

[0009] In one embodiment of the present invention, the switching detection device includes a controller and a battery temperature sensor carried by each of the battery packs, the battery temperature sensor is used to detect the battery temperature corresponding to the battery pack, and the controller is used to calculate the maximum temperature difference between each of the battery packs based on the battery temperature of each of the battery packs; wherein, if the maximum temperature difference is greater than a preset second temperature threshold, the controller generates a third trigger signal, and uses the third trigger signal as a trigger signal to cause the outlet to switch to the inlet, so that the refrigerant flows in the opposite direction.

[0010] In one embodiment of the present invention, the switching detection device includes a first liquid level sensor and a second liquid level sensor, which are respectively arranged in the first liquid storage tank and the second liquid storage tank, the first liquid level sensor is used to detect the first liquid level of the refrigerant in the first liquid storage tank, and the second liquid level sensor is used to detect the second liquid level of the refrigerant in the second liquid storage tank; wherein, if the outlet is set to the first circulation port, and the first liquid level is lower than a preset liquid level threshold, it is determined that the refrigerant in the liquid storage tank located at the first circulation port is insufficient, and the first liquid level sensor generates a fourth trigger signal to switch the outlet to the second circulation port; until the second liquid level is lower than the preset liquid level threshold, a fifth trigger signal is generated by the second liquid level sensor, and then the outlet is switched to the first circulation port, wherein the fourth trigger signal and the fifth trigger signal are respectively used as the trigger signals.

[0011] In one embodiment of the present invention, the battery direct cooling system also includes a four-way valve, which is provided with a first port and a second port, the first port is connected to the first flow port, the second port is connected to the second flow port, and the first port and the second port are used to switch the inlet and outlet of the flow channel.

[0012] In one embodiment of the present invention, the battery direct cooling system further includes an expansion valve, and the four-way valve is further provided with a third port, and the third port is connected to the expansion valve to transport the refrigerant to the flow channel through the expansion valve.

[0013] In one embodiment of the present invention, the battery direct cooling system further includes a compressor, the four-way valve is further provided with a fourth port, and the compressor is connected to the fourth port so that the flow channel transports the refrigerant to the compressor.

[0014] In one embodiment of the present invention, the battery direct cooling system also includes a heater for heating the refrigerant flowing out of the outlet, and the heater includes a first heater and a second heater, the first heater is arranged between the first flow port and the first port, and the second heater is arranged between the second flow port and the second port; wherein, if the first flow port is set as the inlet, the first heater does not work, and the second heater is used to heat the refrigerant flowing out of the second flow port; if the second flow port is set as the inlet, the first heater is used to heat the refrigerant flowing out of the second flow port, and the second heater does not work.

[0015] In one embodiment of the present invention, the battery direct cooling system further includes a third temperature sensor and a fourth temperature sensor, wherein the third temperature sensor is disposed between the first heater and the first port, and is used to detect a third temperature of the refrigerant flowing through the first heater, the fourth temperature sensor is disposed between the second heater and the second port, and is used to detect a fourth temperature of the refrigerant flowing through the second heater, the fifth temperature sensor is disposed between the first heater and the first flow port, and is used to detect a fifth temperature of the refrigerant flowing out of the first flow port, and the sixth temperature sensor is disposed between the second heater and the second flow port, and is used to detect a sixth temperature of the refrigerant flowing out of the first flow port; wherein when the second flow port is set as the inlet, a first superheat of the refrigerant is determined according to the third temperature and the fifth temperature; if the first superheat is greater than a preset temperature difference threshold, the power of the first heater is adjusted; when the first flow port is set as the inlet, a second superheat of the refrigerant is determined according to the fourth temperature and the sixth temperature; if the second superheat is greater than the preset temperature difference threshold, the power of the second heater is adjusted.

[0016] In one embodiment of the present invention, the flow channel and the liquid accumulation groove are both symmetrical structures, and the first flow opening and the second flow opening are arranged on the same side of the direct cooling plate.

[0017] In one embodiment of the present invention, the direct cooling plate includes a bottom plate and a top plate, the flow channel and the liquid accumulation groove are arranged on the bottom plate, and the battery pack is arranged on the top plate.

[0018] In a second aspect, the present invention further provides a vehicle battery management system, wherein the vehicle battery management system is integrated with the battery direct cooling system as described in the above embodiment.

[0019] In a third aspect, the present invention further provides a vehicle, wherein the vehicle is integrated with the battery direct cooling system as described in the above embodiment.

[0020] In a fourth aspect, the present invention further provides a method for direct cooling of a battery, which is used in a direct cooling system of a battery, wherein a flow channel and a liquid accumulation groove are arranged in a direct cooling plate, the flow channel is provided with two flow ports, the liquid accumulation grooves are respectively arranged at the two flow ports, and refrigerant is deposited thereon, the method comprising: selecting any one of the flow ports as an inlet for the refrigerant to flow into the flow channel, and using the other flow port as an outlet for the refrigerant to flow out of the flow channel; using the liquid accumulation groove close to the outlet to replenish the refrigerant in the flow channel, and the liquid accumulation groove close to the inlet to receive the refrigerant flowing into the inlet, so that the refrigerant in the flow channel remains in a saturated state; detecting the temperature of the refrigerant flowing through the outlet, and determining whether to generate a trigger signal for switching the inlet and outlet of the flow channel based on the detection result, and if the trigger signal is generated, switching the outlet to the inlet to allow the refrigerant to flow in the opposite direction.

[0021] Beneficial effects of the present invention: The present invention proposes a battery direct cooling system, method, vehicle battery management system and vehicle, including a direct cooling plate and a switching detection device, wherein a flow channel and a liquid accumulation tank are arranged in the direct cooling plate; wherein a refrigerant flows in the flow channel for absorbing the heat generated by the battery pack, and the flow channel is provided with two flow ports, namely a first flow port and a second flow port, one of the flow ports is optionally used as an inlet for the refrigerant to flow into the flow channel, and the other flow port is optionally used as an outlet for the refrigerant to flow out of the flow channel; the liquid accumulation tank includes a first liquid accumulation tank and a second liquid accumulation tank, which are respectively arranged at the first flow port and the second flow port, and refrigerant is deposited, the liquid accumulation tank close to the outlet is used to replenish the refrigerant in the flow channel, and the liquid accumulation tank close to the inlet is used to receive the refrigerant flowing into the inlet, so that the refrigerant in the flow channel remains in a saturated state; if a trigger signal generated by the switching detection device is received, the outlet is switched to the inlet to allow the refrigerant to flow in the reverse direction. In this way, firstly, by setting liquid accumulation grooves at the inlet and outlet of the flow channel in the direct cooling plate to replenish the refrigerant in the flow channel, the refrigerant in the flow channel can be kept in a gas-liquid saturated state to the greatest extent, thereby improving the heat exchange capacity of the direct cooling system; secondly, by controlling the refrigerant inlet and outlet, that is, the interchange of the flow channel inlet and outlet, it is ensured that there is always liquid refrigerant in the liquid accumulation groove near the flow channel outlet, thereby improving the temperature uniformity performance of the direct cooling system, and being able to avoid the rapid increase in the temperature of the battery pack near the flow channel outlet, so that the direct cooling system achieves a temperature uniformity effect, improves the temperature difference between the battery packs, and improves the working performance and service life of the battery; thirdly, the structural design of the direct cooling plate is simple, and the requirements for the manufacturing process are low.

[0022] It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The drawings herein are incorporated into the specification and constitute a part of the specification, showing embodiments consistent with the present invention, and together with the specification, are used to explain the principles of the present invention. Obviously, the drawings described below are only some embodiments of the present invention, and for those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative work. In the drawings:

[0024] Figure 1 is a schematic diagram of a direct cooling plate flow channel shown in an exemplary embodiment of the present invention;

[0025] Figure 2 is a structural schematic diagram of a battery direct cooling system shown in an exemplary embodiment of the present invention;

[0026] Figure 3 is a schematic structural diagram of a bottom plate and a top plate of a direct cooling plate shown in an exemplary embodiment of the present invention;

[0027] Figure 4 is a schematic diagram of a refrigerant circulation structure shown in an exemplary embodiment of the present invention;

[0028] Figure 5 is a schematic diagram of a local structure of a direct cooling plate shown in an exemplary embodiment of the present invention;

[0029] Figure 6 It is a flow chart of a method for direct cooling of a battery shown in an exemplary embodiment of the present invention. DETAILED DESCRIPTION

[0030] The following will describe the embodiments of the present invention with reference to the accompanying drawings and preferred embodiments. Those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be understood that the preferred embodiments are only for illustrating the present invention, not for limiting the scope of protection of the present invention.

[0031] It should be noted that the illustrations provided in the following embodiments are only schematic illustrations of the basic concept of the present invention, and thus the drawings only show components related to the present invention rather than being drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component may be changed arbitrarily, and the component layout may also be more complicated.

[0032] In the following description, numerous details are discussed to provide a more thorough explanation of the embodiments of the present invention. However, it is obvious to those skilled in the art that the embodiments of the present invention can be implemented without these specific details. In other embodiments, well-known structures and devices are shown in the form of block diagrams rather than in detail to avoid making the embodiments of the present invention difficult to understand.

[0033] It should be noted that the direct cooling system mainly absorbs heat from the battery by evaporating the refrigerant in the direct cooling plate. The direct cooling plate is similar to the evaporator in the traditional refrigeration system, which is a latent heat exchange. Latent heat is the heat absorbed by the refrigerant in the process of changing from liquid to gas while the temperature remains unchanged. When the refrigerator only absorbs latent heat, it will not cause the temperature to rise (or fall). This heat only plays a potential role in temperature changes. Therefore, in order to efficiently perform latent heat exchange, it is necessary to ensure that the refrigerant is always in a saturated state, that is, when liquid and vapor exist at the same time, the refrigerant is in a saturated state. It should be understood that water cooling means that the coolant absorbs the heat of the battery pack as it flows along the flow channel, causing its own temperature to gradually increase. In the direct cooling system, the pressure of the refrigerant gradually decreases as it flows along the flow channel, causing the saturation temperature of the refrigerant to decrease, that is, the temperature at which the refrigerant changes from liquid to gas under a certain pressure. This temperature depends on the pressure. Different refrigerants will have different saturation temperatures under the same pressure. The lower the saturation temperature of the refrigerant, the better the cooling effect. Therefore, direct cooling is more efficient and has stronger heat dissipation capacity. However, due to the growing demand for mileage in new energy vehicles, the battery packs in the vehicles are getting bigger and bigger, and the size of the direct cooling plate is also expanding. Compared with the size of the traditional evaporator, it has increased several times or even more than ten times, making it difficult to ensure that the refrigerant is in a gas-liquid saturated state everywhere in the direct cooling plate, resulting in uneven cooling and easy local drying, especially at the outlet position at the end of the flow channel, which hinders the heat exchange of the battery pack, reduces the heat exchange efficiency, and causes the temperature to rise rapidly, resulting in a larger temperature difference between the battery packs. Therefore, it is necessary to ensure that the temperature is uniform when the battery pack is cooled by the direct cooling plate to avoid excessive temperature differences between the battery packs.

[0034] See also Figure 1 , is a schematic diagram of a direct cooling plate flow channel according to an exemplary embodiment of the present invention. Figure 1 As shown, in the related art, a distributed flow channel structure is set in the direct cooling plate to improve the temperature uniformity of the direct cooling plate during heat exchange. However, the distributed flow channel structure has limited effect on the improvement of the temperature uniformity of the direct cooling plate heat exchange, and the flow channel is too tortuous and complicated, which will cause excessive pressure drop of the refrigerant and affect the normal operation of the compressor.

[0035] Therefore, in order to solve the above problems, the present invention proposes a battery direct cooling system, in which liquid accumulation grooves are set at the inlet and outlet of the flow channel in the direct cooling plate, so that the refrigerant in the flow channel can be kept in a gas-liquid saturated state to the greatest extent, thereby improving the heat exchange capacity, and by controlling the refrigerant inlet and outlet, that is, the interchange of the flow channel inlet and outlet, it is ensured that there is always liquid refrigerant in the liquid accumulation groove near the flow channel outlet, thereby improving the temperature uniformity performance of the direct cooling system, being able to avoid the rapid increase in the temperature of the battery pack near the flow channel outlet, so that the direct cooling system achieves a temperature uniformity effect, improves the temperature difference between battery packs, and improves the working performance and service life of the battery.

[0036] See also Figure 2 , is a schematic diagram of the structure of a battery direct cooling system shown in an exemplary embodiment of the present invention. This exemplary embodiment provides a battery direct cooling system, comprising at least: a direct cooling plate and a switching detection device, wherein a flow channel and a liquid accumulation tank are arranged in the direct cooling plate; wherein a refrigerant flows in the flow channel for absorbing the heat generated by the battery pack, and the flow channel is provided with two flow ports, namely a first flow port and a second flow port, wherein one flow port is selected as an inlet for the refrigerant to flow into the flow channel, and the other flow port is selected as an outlet for the refrigerant to flow out of the flow channel; the liquid accumulation tank comprises a first liquid accumulation tank and a second liquid accumulation tank, which are respectively arranged at the first flow port and the second flow port, and refrigerant is deposited therein, the liquid accumulation tank near the outlet is used to replenish the refrigerant in the flow channel, and the liquid accumulation tank near the inlet is used to receive the refrigerant flowing into the inlet, so that the refrigerant in the flow channel remains in a saturated state; if a trigger signal generated by the switching detection device is received, the outlet is switched to the inlet to allow the refrigerant to flow in the reverse direction.

[0037] In one embodiment of the present invention, as the refrigeration process using the refrigerant proceeds, if the liquid refrigerant in the saturated refrigerant is vaporized into a gaseous state, and the battery pack is still generating heat, then the refrigerant will be insufficient and dry, resulting in a decrease in the refrigeration effect, and even the temperature of the refrigerant will rise rapidly, causing local overheating in the direct cooling plate, thereby damaging other components in the direct cooling system. In particular, at the location of the flow channel outlet of the direct cooling plate, it is usually necessary to use a battery to heat the refrigerant to a state with a certain degree of superheat. Therefore, in order to prevent the refrigerant near the flow channel outlet from being dried up, a liquid accumulation tank is set at the outlet of the flow channel, and the liquid refrigerant deposited in the corresponding liquid accumulation tank at the flow channel outlet is used to replenish the refrigerant in the flow channel, so that the refrigerant in the flow channel remains in a gas-liquid saturated state. In addition, because the refrigerant in the liquid storage tank corresponding to the flow channel outlet is burned dry and the refrigerant in the flow channel cannot be replenished in time, the temperature of the refrigerant will increase rapidly, and the inlet and outlet of the flow channel need to be switched, so that the liquid storage tank corresponding to the switch flow channel outlet is switched to another liquid storage tank containing refrigerant, and the liquid storage tank corresponding to the original outlet is located at the inlet of the flow channel to receive the liquid refrigerant flowing into the inlet. Therefore, a switching detection device is provided in the battery direct cooling system. When a trigger signal generated by the switching detection device is received, the inlet and outlet of the flow channel are controlled to switch.

[0038] Specifically, the flow channel and the liquid accumulation groove are both symmetrical structures, the first flow opening and the second flow opening are arranged on the same side of the direct cooling plate, the position of the first liquid accumulation groove is the first flow opening, and the position of the second liquid accumulation groove is the second flow opening. Figure 2 As shown, the structure of the flow channel is a simple symmetrical structure, the first liquid accumulation groove C1 is a groove located at the first flow opening, the second liquid accumulation groove C2 is a groove located at the second flow opening, and the first liquid accumulation groove C1 and the second liquid accumulation groove C2 are grooves on the plane where the flow channels are located. In this way, the direct cooling plate is a simple symmetrical structure with low requirements on the manufacturing process.

[0039] In one embodiment of the present invention, the refrigerant is also called a refrigerant, which usually takes away the heat generated by the battery pack from the flow channel of the direct cooling plate in a reversible phase change (such as a gas-liquid phase change), thereby achieving a heat exchange cooling effect. The refrigerant entering the inlet of the flow channel in the direct cooling plate is in a low-temperature and low-pressure gas-liquid saturated state. Because the density of the liquid is greater than the density of the gas, the liquid refrigerant will slowly settle into the liquid accumulation tank due to gravity, and the remaining gas-liquid mixed refrigerant will continue to vaporize in the direct cooling plate and transform into a fully gaseous refrigerant, thereby efficiently absorbing the heat generated by the battery pack and quickly cooling the battery.

[0040] See also Figure 3 , is a schematic diagram of the structure of the bottom plate and the top plate of the direct cooling plate shown in an exemplary embodiment of the present invention. Figure 3As shown, the direct cooling plate includes a bottom plate and a top plate, the flow channel and the liquid accumulation groove are arranged on the bottom plate, and the battery pack, that is, the battery module is arranged on the top plate.

[0041] In one embodiment of the present invention, a plurality of battery packs are arranged on the upper surface of the top plate, and the top plate of the direct cooling plate is covered on the bottom plate so that the flow channel, the first liquid accumulation groove C1 and the second liquid accumulation groove C2 on the bottom plate are isolated from the battery packs. Figure 2 As shown, the liquid accumulation tank is arranged at a position away from the flow channel inlet and outlet of the battery pack and at a certain distance from the battery pack. In this way, the liquid refrigerant deposited in the liquid accumulation tank is kept away from the battery pack, and the liquid refrigerant in the liquid accumulation tank at the outlet is burned dry, so that the refrigerant at the flow channel outlet is replenished in time, so that the refrigerant is still in a saturated state when it flows to the flow channel outlet, and the heat exchange efficiency is high.

[0042] Specifically, the switching detection device comprises at least the following three situations:

[0043] First, the switching detection device includes a first temperature sensor and a second temperature sensor, which are respectively arranged at the first flow port and the second flow port, the first temperature sensor is used to detect the first temperature of the refrigerant flowing through the first flow port, and the second temperature sensor is used to detect the second temperature flowing through the second flow port; wherein, if the outlet is set to the first flow port, and the first temperature is higher than the preset first temperature threshold, it is determined that the refrigerant in the liquid accumulation tank located at the first flow port is insufficient, and the first temperature sensor generates a first trigger signal to switch the outlet to the second flow port; until the second temperature is higher than the preset first temperature threshold, the second trigger signal is generated by the second temperature sensor, and then the outlet is switched to the first flow port, wherein the first trigger signal and the second trigger signal are respectively used as trigger signals.

[0044] like Figure 2 As shown, Figure 2T1 is the first temperature sensor, and T2 is the second temperature sensor. When the first flow port is the outlet of the flow channel, the first liquid accumulation tank C1 automatically replenishes the refrigerant near the outlet in the flow channel, and the liquid accumulation tank 2 deposits the liquid refrigerant flowing into the inlet of the flow channel, that is, the second flow port. At this time, the temperature of the refrigerant at the first flow port is detected by the first temperature sensor T1 as the first temperature. If the first temperature is higher than the preset first temperature threshold, the refrigerant in the flow channel is insufficient and has been burned dry. The first temperature sensor T1 will generate a first trigger signal to control the four-way valve to switch the inlet and outlet of the flow channel. After the switch, the second flow port is the outlet of the flow channel, the second liquid accumulation tank C2 automatically replenishes the refrigerant near the outlet in the flow channel, and the liquid accumulation tank 2 deposits the refrigerant flowing into the inlet of the flow channel to prepare for the next switch of the inlet and outlet. At this time, the second temperature sensor T2 is used to detect the temperature of the refrigerant at the second flow port as the second temperature. If the second temperature is higher than the preset first temperature threshold, the refrigerant in the flow channel is insufficient and has been burned dry. The second temperature sensor T2 will generate a first trigger signal to control the four-way valve to switch the inlet and outlet of the flow channel. In this way, by setting a temperature sensor at the outlet of the flow channel, the temperature of the refrigerant flowing through the outlet of the flow channel can be detected more sensitively and accurately, and the accuracy of controlling the switching of the inlet and outlet of the flow channel is high.

[0045] Second, the switching detection device includes a controller and a battery temperature sensor carried by each battery pack, the battery temperature sensor is used to detect the battery temperature of the corresponding battery pack, and the controller is used to calculate the maximum temperature difference between the battery packs according to the battery temperature of each battery pack; wherein, if the maximum temperature difference is greater than a preset second temperature threshold, the controller generates a third trigger signal, and uses the third trigger signal as a trigger signal to cause the outlet to switch to the inlet, so that the refrigerant flows in the opposite direction.

[0046] In one embodiment of the present invention, because the battery pack usually carries a temperature sensor for monitoring its own temperature, that is, a battery temperature sensor, the maximum temperature difference between each battery pack can be calculated by collecting the battery temperature of the corresponding battery pack through each battery temperature sensor. In addition, in the process of cooling the battery pack with a refrigerant, if the temperature difference between the battery packs begins to rise rapidly, it means that the refrigerant is insufficient and local drying occurs, resulting in a decrease in heat exchange efficiency and a larger temperature difference between the battery packs, and the refrigerant in the flow channel needs to be supplemented. Therefore, a communication connection is established between the controller and the battery temperature sensor. If the maximum temperature difference calculated by the controller based on the battery temperature of each battery pack is greater than the preset second temperature threshold, a third trigger signal can be generated to control the outlet of the flow channel to switch to the inlet. In this way, the manufacturing cost is saved, that is, the difficulty of the manufacturing process is reduced.

[0047] Third, the switching detection device includes a first liquid level sensor and a second liquid level sensor, which are respectively arranged in the first liquid storage tank and the second liquid storage tank, the first liquid level sensor is used to detect the first liquid level of the refrigerant in the first liquid storage tank, and the second liquid level sensor is used to detect the second liquid level of the refrigerant in the second liquid storage tank; wherein, if the outlet is set to the first flow port, and the first liquid level is lower than the preset liquid level threshold, it is determined that the refrigerant in the liquid storage tank located at the first flow port is insufficient, and the first liquid level sensor generates a fourth trigger signal to switch the outlet to the second flow port; until the second liquid level is lower than the preset liquid level threshold, the fifth trigger signal is generated by the second liquid level sensor, and then the outlet is switched to the first flow port, wherein the fourth trigger signal and the fifth trigger signal are respectively used as trigger signals.

[0048] In one embodiment of the present invention, a liquid level sensor is provided in the liquid reservoir to monitor the liquid level of the refrigerant in the liquid reservoir in real time. When the liquid level of the refrigerant in the liquid reservoir at the outlet is detected to be lower than the preset liquid level threshold, it indicates that the refrigerant in the liquid reservoir corresponding to the outlet of the flow channel is insufficient and has been burned dry. Therefore, the outlet of the flow channel is switched to the inlet. In this way, the refrigerant in the flow channel can be replenished in time, the temperature difference between the battery packs is avoided to be too large, and the uniformity performance in the direct cooling system is improved.

[0049] Through the above method, the inlet and outlet of the flow channel are cyclically switched. In this way, when the direct cooling plate exchanges heat through the refrigerant, the refrigerant in each part of the flow channel is in gas-liquid two-phase through the design of the liquid accumulation tank. While improving the temperature uniformity performance, efficient latent heat exchange is maintained, which greatly improves the heat exchange capacity of the battery direct cooling system, thereby reducing the energy consumption of the thermal management system in the vehicle and increasing the vehicle's cruising range.

[0050] See also Figure 4 , is a schematic diagram of a refrigerant circulation structure shown in an exemplary embodiment of the present invention. Figure 4 As shown, the battery direct cooling system also includes a four-way valve V, an expansion valve and a compressor. The four-way valve V is provided with a first port G1, a second port G2, a third port G3 and a fourth port G4, the first port G1 is connected to the first flow port, the second port G2 is connected to the second flow port, the first port G1 and the second port G2 are used to switch the inlet and outlet of the flow channel, the third port G3 is connected to the expansion valve to transport the refrigerant to the flow channel through the expansion valve, and the fourth port G4 is connected to the compressor to enable the flow channel to transport the refrigerant to the compressor.

[0051] In one embodiment of the present invention, if the inlet of the current flow channel is the second flow port, then when the regulating valve receives a trigger signal, the inlet of the flow channel is switched to the first flow port; if the inlet of the current flow channel is the first flow port, then when the regulating valve receives a trigger signal, the inlet of the flow channel is switched to the second flow port. Because the flow channel structure of the direct cooling plate is completely symmetrical, the working pressure of the direct cooling system will not change after replacing the flow channel inlet and outlet to reverse the flow of the refrigerant, and it will not affect the working conditions of other components other than the direct cooling plate, such as the compressor, expansion valve and condenser, etc. Therefore, the reliability of heat exchange of the direct cooling system is high.

[0052] In one embodiment of the present invention, if the inlet of the flow channel is set as the first flow port, the flow direction of the refrigerant is the expansion valve, the third port G3, the four-way valve V, the first port G1, the flow channel, the second port G2, the four-way valve V and the fourth port G4; if the inlet of the flow channel is set as the second flow port, the flow direction of the refrigerant is the expansion valve, the third port G3, the four-way valve V, the second port G2, the flow channel, the first port G2, the four-way valve V and the fourth port G4. In this way, by controlling the switching of the flow channel inlet and outlet, there is liquid refrigerant in the liquid accumulation tank corresponding to the flow channel outlet, thereby reducing the temperature difference of the battery. Because the flow channel is a symmetrical structure, based on the short board effect, the temperature difference between the battery packs can be reduced by half to a certain extent, that is, the temperature difference can be reduced from about 10°C (degrees Celsius) to about 5°C, thereby improving the temperature uniformity performance of the direct cooling system and improving the charging performance, discharging performance and service life of the battery.

[0053] In one embodiment of the present invention, since the refrigerant entering the compressor must remain in a full gas state, otherwise liquid hammer will occur, that is, the refrigerant fails to or does not fully absorb heat and evaporates, and the refrigerant liquid or wet steam is sucked into the compressor by the compressor, which will damage the air compressor. Therefore, the refrigerant flowing out of the outlet of the flow channel needs to have a certain degree of superheat (temperature difference). A heater is provided at the outlet of the flow channel to heat the refrigerant flowing out of the outlet to ensure the superheat of the refrigerant, and avoid the situation where the refrigerant is heated by the battery cell close to the outlet of the flow channel, and the corresponding liquid accumulation tank at the outlet is quickly dried up.

[0054] See also Figure 5 , is a schematic diagram of a local structure of a direct cooling plate according to an exemplary embodiment of the present invention. Figure 2 and Figure 5As shown, the battery direct cooling system also includes a heater for heating the refrigerant flowing out of the outlet, and the heater includes a first heater P1 and a second heater P2, the first heater P1 is arranged between the first flow port T1 and the first port, and the second heater P2 is arranged between the second flow port and the second port; wherein, if the first flow port is set as an inlet, the first heater P1 does not work, and the second heater P2 is used to heat the refrigerant flowing out of the second flow port; if the second flow port is set as an inlet, the first heater P1 is used to heat the refrigerant flowing out of the second flow port, and the second heater P2 does not work.

[0055] In one embodiment of the present invention, because the pressure of the refrigerant at the inlet of the flow channel is greater than the pressure at the outlet, when the refrigerant is in a saturated state at both the inlet and the outlet, the temperature of the refrigerant at the inlet is greater than the temperature at the outlet. In order to ensure the superheat of the refrigerant flowing out of the outlet of the flow channel in the direct cooling plate, so that the refrigerant is in a low-temperature and low-pressure full gas state, only the heater corresponding to the flow channel outlet is used to adjust the temperature of the refrigerant flowing out of the flow channel outlet so that its temperature meets the superheat, and the heater corresponding to the flow channel inlet does not work. Among them, the power of the heater is calibrated by the flow rate and pressure of the refrigerant in the direct cooling system, and the temperature difference of the refrigerant after being heated by the heater can be adjusted according to the actual situation, and can be adjusted to 5 degrees Celsius or below.

[0056] Specifically, combined Figure 2 and Figure 5 As shown, the battery direct cooling system also includes a third temperature sensor T3 and a fourth temperature sensor T4. The third temperature sensor T3 is arranged between the first heater and the first port, and is used to detect the third temperature of the refrigerant flowing through the first heater. The fourth temperature sensor T4 is arranged between the second heater and the second port, and is used to detect the fourth temperature of the refrigerant flowing through the second heater. The fifth temperature sensor is arranged between the first heater and the first flow port, and is used to detect the fifth temperature of the refrigerant flowing out of the first flow port. The sixth temperature sensor is arranged between the second heater and the second flow port, and is used to detect the sixth temperature of the refrigerant flowing out of the first flow port; wherein, when the second flow port is set as an inlet, the first superheat of the refrigerant is determined according to the third temperature and the fifth temperature; if the first superheat is greater than the preset temperature difference threshold, the power of the first heater is adjusted; when the first flow port is set as an inlet, the second superheat of the refrigerant is determined according to the fourth temperature and the sixth temperature; if the second superheat is greater than the preset temperature difference threshold, the power of the second heater is adjusted.

[0057] In one embodiment of the present invention, temperature sensors are respectively arranged at both ends of the heater, including detecting the temperature of the refrigerant when it does not flow through the heater in working state, and the temperature of the refrigerant after being heated by the heater in working state, so as to calculate the superheat of the refrigerant, judge whether the superheat meets the preset temperature difference threshold, avoid the superheat of the refrigerant failing to meet the requirements, ensure that no liquid refrigerant enters the compressor, and prevent the liquid rush phenomenon from affecting the safe operation of the compressor, wherein the preset temperature difference threshold is preferably 5 degrees Celsius or less, and can also be adjusted according to actual conditions. The first heater P1 and the second heater P2 do not work at the same time. When the first heater P1 works, the superheat of the refrigerant is the temperature difference between the third temperature and the fifth temperature; when the second heater P2 works, the superheat of the refrigerant is the temperature difference between the fourth temperature and the sixth temperature.

[0058] In one embodiment of the present invention, the functions of the fifth temperature sensor and the sixth temperature sensor can be implemented by the first temperature sensor and the second temperature sensor. Therefore, when the first temperature sensor and the second temperature sensor exist in the direct cooling system, there is no need to additionally set up the fifth temperature sensor and the sixth temperature sensor. In this case, when the first heater P1 is working, the superheat of the refrigerant is the temperature difference between the third temperature and the first temperature; when the second heater P2 is working, the superheat of the refrigerant is the temperature difference between the fourth temperature and the second temperature.

[0059] The present invention provides a battery direct cooling system. First, by arranging liquid accumulation grooves at the inlet and outlet of the flow channel in the direct cooling plate to replenish the refrigerant in the flow channel, the refrigerant in the flow channel can be kept in a gas-liquid saturated state to the greatest extent, thereby improving the heat exchange capacity of the direct cooling system and having high reliability; second, by controlling the refrigerant inlet and outlet, that is, the interchange of the flow channel inlet and outlet, it is ensured that there is always liquid refrigerant in the liquid accumulation groove near the flow channel outlet, thereby improving the temperature uniformity performance of the direct cooling system, being able to avoid the rapid increase in the temperature of the battery pack near the flow channel outlet, enabling the direct cooling system to achieve a temperature uniformity effect, improving the temperature difference between the battery packs, and improving the working performance and service life of the battery; third, the direct cooling plate has a simple structural design and low requirements on the manufacturing process; fourth, a heater is arranged at the outlet of the flow channel to avoid heating the flow channel through the battery cells in the battery pack near the flow channel outlet, thereby ensuring the uniformity of the refrigerant overheat and the temperature difference between the battery packs.

[0060] An embodiment of the present invention further provides a vehicle battery management system, which integrates the battery direct cooling system in the above embodiment.

[0061] An embodiment of the present invention further provides a vehicle, wherein the vehicle is integrated with the battery direct cooling system as in the above embodiment.

[0062] See also Figure 6, is a flow chart of a battery direct cooling method shown in an exemplary embodiment of the present invention. As shown in 6, the battery direct cooling method is used in a battery direct cooling system, in which a flow channel and a liquid accumulation tank are arranged in a direct cooling plate, the flow channel is arranged with two flow ports, the liquid accumulation tank is arranged at the two flow ports respectively, and refrigerant is deposited, and at least steps S610 to S630 are described in detail as follows:

[0063] Step S610, selecting one of the flow openings as an inlet for the refrigerant to flow into the flow channel, and selecting another flow opening as an outlet for the refrigerant to flow out of the flow channel;

[0064] Step S620, using the liquid accumulating tank near the outlet to replenish the refrigerant in the flow channel, and the liquid accumulating tank near the inlet to receive the refrigerant flowing into the inlet, so that the refrigerant in the flow channel remains in a saturated state.

[0065] Step S630, detecting the temperature of the refrigerant flowing through the outlet, and determining whether to generate a trigger signal for switching the inlet and outlet of the flow channel based on the detection result. If a trigger signal is generated, the outlet is switched to the inlet to allow the refrigerant to flow in the reverse direction.

[0066] Specifically, the two flow ports are divided into a first flow port and a second flow port; when the outlet is set to the first flow port, the first temperature of the refrigerant flowing through the first flow port is detected. If the first temperature is higher than the preset temperature threshold, the refrigerant in the liquid accumulation tank located in the first flow port has been burned dry, and a trigger signal is generated to switch the outlet to the second flow port; the second temperature of the refrigerant flowing through the second flow port is detected. If the second temperature is higher than the preset temperature threshold, a trigger signal is generated, and then the outlet is switched to the first flow port.

[0067] It should be noted that the battery direct cooling method provided in the above embodiment and the battery direct cooling system provided in the above embodiment belong to the same concept, wherein the specific manner of performing the operation of each step has been described in detail in the system embodiment and will not be repeated here.

[0068] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical concept disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. A battery direct cooling system, characterized in that: include: A direct cooling plate and a switching detection device, wherein a flow channel and a liquid accumulation tank are arranged in the direct cooling plate; Wherein, a refrigerant flows in the flow channel for absorbing heat generated by the battery pack, and the flow channel is provided with two flow openings, namely a first flow opening and a second flow opening, and one of the flow openings is selected as an inlet for the refrigerant to flow into the flow channel, and the other flow opening is selected as an outlet for the refrigerant to flow out of the flow channel; The liquid accumulation tank includes a first liquid accumulation tank and a second liquid accumulation tank, which are respectively arranged at the first circulation port and the second circulation port and deposited with the refrigerant, the liquid accumulation tank close to the outlet is used to replenish the refrigerant in the flow channel, and the liquid accumulation tank close to the inlet is used to receive the refrigerant flowing into the inlet, so that the refrigerant in the flow channel remains in a saturated state; If a trigger signal generated by the switching detection device is received, the outlet is switched to the inlet to allow the refrigerant to flow in the reverse direction; The switching detection device includes a first temperature sensor and a second temperature sensor, which are respectively arranged at the first circulation port and the second circulation port, the first temperature sensor is used to detect a first temperature of the refrigerant flowing through the first circulation port, and the second temperature sensor is used to detect a second temperature of the refrigerant flowing through the second circulation port; Wherein, if the outlet is set as the first circulation port, and the first temperature is higher than a preset first temperature threshold, it is determined that the refrigerant in the liquid accumulation tank located at the first circulation port is insufficient, and the first temperature sensor generates a first trigger signal to switch the outlet to the second circulation port; Until the second temperature is higher than the preset first temperature threshold, a second trigger signal is generated by the second temperature sensor, and then the outlet is switched to the first flow port, wherein the first trigger signal and the second trigger signal are respectively used as the trigger signals.

2. The battery direct cooling system according to claim 1, characterized in that: The switching detection device includes a controller and a battery temperature sensor carried by each of the battery packs, the battery temperature sensor is used to detect the battery temperature of the corresponding battery pack, and the controller is used to calculate the maximum temperature difference between each of the battery packs according to the battery temperature of each of the battery packs; If the maximum temperature difference is greater than a preset second temperature threshold, the controller generates a third trigger signal, and uses the third trigger signal as a trigger signal to cause the outlet to switch to the inlet, so that the refrigerant flows in the reverse direction.

3. The battery direct cooling system according to claim 1, characterized in that: The switching detection device comprises a first liquid level sensor and a second liquid level sensor, which are respectively arranged in the first liquid sump and the second liquid sump, the first liquid level sensor being used to detect a first liquid level of the refrigerant in the first liquid sump, and the second liquid level sensor being used to detect a second liquid level of the refrigerant in the second liquid sump; Wherein, if the outlet is set as the first circulation port, and the first liquid level is lower than a preset liquid level threshold, it is determined that the refrigerant in the liquid accumulation tank located at the first circulation port is insufficient, and the first liquid level sensor generates a fourth trigger signal to switch the outlet to the second circulation port; Until the second liquid level is lower than the preset liquid level threshold, the fifth trigger signal is generated by the second liquid level sensor, and then the outlet is switched to the first flow port, wherein the fourth trigger signal and the fifth trigger signal are respectively used as the trigger signals.

4. The battery direct cooling system according to claim 1, characterized in that: The battery direct cooling system also includes a four-way valve, which is provided with a first port and a second port, the first port is connected to the first flow port, the second port is connected to the second flow port, and the first port and the second port are used to switch the inlet and outlet of the flow channel.

5. The battery direct cooling system according to claim 4, characterized in that: The battery direct cooling system further includes an expansion valve. The four-way valve is further provided with a third port. The third port is connected to the expansion valve so as to transport the refrigerant to the flow channel through the expansion valve.

6. The battery direct cooling system according to claim 4, characterized in that: The battery direct cooling system further includes a compressor, and the four-way valve is further provided with a fourth port, and the compressor is connected to the fourth port so that the flow channel transports the refrigerant to the compressor.

7. The battery direct cooling system according to claim 4, characterized in that: The battery direct cooling system further includes a heater for heating the refrigerant flowing out of the outlet, the heater including a first heater and a second heater, the first heater being disposed between the first flow port and the first port, and the second heater being disposed between the second flow port and the second port; Wherein, if the first flow port is set as the inlet, the first heater does not work, and the second heater is used to heat the refrigerant flowing out of the second flow port; If the second flow port is set as the inlet, the first heater is used to heat the refrigerant flowing out of the second flow port, and the second heater does not work.

8. The battery direct cooling system according to claim 7, characterized in that: The battery direct cooling system further includes a third temperature sensor, a fourth temperature sensor, a fifth temperature sensor and a sixth temperature sensor, wherein the third temperature sensor is disposed between the first heater and the first port, and is used to detect a third temperature of the refrigerant flowing through the first heater, the fourth temperature sensor is disposed between the second heater and the second port, and is used to detect a fourth temperature of the refrigerant flowing through the second heater, the fifth temperature sensor is disposed between the first heater and the first flow port, and is used to detect a fifth temperature of the refrigerant flowing out of the first flow port, and the sixth temperature sensor is disposed between the second heater and the second flow port, and is used to detect a sixth temperature of the refrigerant flowing out of the second flow port; Wherein, when the second flow port is set as the inlet, the first superheat degree of the refrigerant is determined according to the third temperature and the fifth temperature; If the first superheat degree is greater than a preset temperature difference threshold, adjusting the power of the first heater; When the first flow port is set as the inlet, determining a second superheat degree of the refrigerant according to the fourth temperature and the sixth temperature; If the second superheat degree is greater than the preset temperature difference threshold, the power of the second heater is adjusted.

9. The battery direct cooling system according to any one of claims 1 to 8, characterized in that: The flow channel and the liquid accumulation groove are both symmetrical structures, and the first flow opening and the second flow opening are arranged on the same side of the direct cooling plate.

10. The battery direct cooling system according to claim 1, characterized in that: The direct cooling plate includes a bottom plate and a top plate, the flow channel and the liquid accumulation groove are arranged on the bottom plate, and the battery pack is arranged on the top plate.

11. A vehicle battery management system, characterized in that: The vehicle battery management system is integrated with a battery direct cooling system as claimed in any one of claims 1 to 10.

12. A vehicle, characterized in that: The vehicle is integrated with the battery direct cooling system according to any one of claims 1 to 10.

13. A method for direct cooling of a battery, characterized in that: Applied to a battery direct cooling system as claimed in any one of claims 1 to 10, wherein a flow channel and a liquid accumulation groove are arranged in a direct cooling plate, the flow channel is provided with two flow openings, namely a first flow opening and a second flow opening, the liquid accumulation groove is respectively arranged at the two flow openings and refrigerant is deposited, the method comprising: Select one of the circulation ports as an inlet for the refrigerant to flow into the flow channel, and select another of the circulation ports as an outlet for the refrigerant to flow out of the flow channel; The refrigerant in the flow channel is replenished by the liquid accumulating groove near the outlet, and the liquid accumulating groove near the inlet receives the refrigerant flowing into the inlet, so that the refrigerant in the flow channel is kept in a saturated state; Detecting the temperature of the refrigerant flowing through the outlet, determining whether to generate a trigger signal for switching the inlet and outlet of the flow passage based on the detection result, and if the trigger signal is generated, switching the outlet to the inlet to allow the refrigerant to flow in the reverse direction; wherein a first temperature of the refrigerant flowing through the first circulation port is detected, and a second temperature of the refrigerant flowing through the second circulation port is detected; If the outlet is set as the first circulation port, and the first temperature is higher than a preset first temperature threshold, it is determined that the refrigerant in the liquid accumulation tank located at the first circulation port is insufficient, and a first trigger signal is generated to switch the outlet to the second circulation port; Until the second temperature is higher than the preset first temperature threshold, a second trigger signal is generated, and then the outlet is switched to the first flow port, wherein the first trigger signal and the second trigger signal are respectively used as the trigger signals.

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