Battery pack cooling control circuit, pulse cooling control circuit and control method

Abstract

The invention discloses a battery pack cooling control circuit, a pulse cooling control circuit and a control method, which are applied to the technical field of battery pack cooling control, and are composed of a controller, a first cooling control unit, a second cooling control unit and a battery management system, the first cooling control unit comprises a first power supply, a first triode, a first resistor and a first load, and the second cooling control unit comprises a second power supply, a second triode, a second load and a second resistor. The battery pack is cooled in combination with the battery management system, so that the power consumption of extra cooling in the fast charging process of the battery pack is greatly reduced, and the cooling effect is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of electric vehicle cooling control, and in particular to a battery pack cooling control circuit, a pulse cooling control circuit, and a control method. Background Art

[0002] With the technological iteration of electric vehicles, fast charging is currently the mainstream energy replenishment technology direction. The current technical directions are divided into battery cell design, whole package system design and BMS design. The battery cell end is designed through material optimization so that it can bear a large amount of heat in the internal and external circuits during high-current charging; the BMS end is mainly divided into passive protection and active protection. In passive protection, the battery cell heats up during charging. When over-temperature is detected, it is fed back to the whole vehicle, and then charging at the charging pile is stopped. Active protection is to control the vehicle's thermal management system to cool the battery cells in the battery pack when over-temperature is detected. The turbulent effect generated by the pulsed cooling fluid during the flow process, that is, the formation of differential speed during the flow of the fluid, and the temperature gradient in the pipeline will produce a large turbulent temperature boundary layer. This phenomenon can increase the heat exchange rate of the pipeline wall. Improve the heat exchange rate between the cooling surface and the object.

[0003] The fast charging process actually generates a large amount of heat in the battery cells, which in turn affects the battery life. When the heat accumulates to a certain level, dangerous events such as thermal runaway may occur. Therefore, how to maintain the battery cells at a relatively comfortable temperature during fast charging is the main technical obstacle to fast charging. Secondly, during supercharging, the heat generated by the entire battery pack is greater than the heat generated under the vehicle's driving conditions. Relying solely on thermal management on the vehicle side to cool the entire battery pack is not enough to support the requirements of high-rate charging in the future. Therefore, how to control pulse water cooling and how to implement multiple forms of pulse cooling during the charging process are current problems that need to be solved. Summary of the Invention

[0004] In order to solve the above technical problems, the embodiments of the present invention provide a battery pack cooling control circuit, a pulse cooling control circuit and a control method to solve the technical problems in the prior art that the cooling effect is poor during the charging process of electric vehicles and the battery cannot be cooled down quickly.

[0005] A first aspect of an embodiment of the present invention provides a battery pack cooling control circuit, the circuit including a controller, a first cooling control unit, a second cooling control unit and a battery management system, wherein:

[0006] A first cooling control unit includes: a first power supply, a first transistor, a first resistor, and a first load, wherein the positive electrode of the first power supply is connected to the first end of the first resistor, the second end of the first resistor is connected to the emitter of the first transistor, the collector of the first transistor is connected to the first end of the first load, the second end of the first load is connected to the negative electrode of the first power supply, and the base of the first transistor is connected to the controller;

[0007] A second cooling control unit includes: a second power supply, a second transistor, a second load, and a second resistor, wherein the positive electrode of the second power supply is connected to the first end of the second resistor, the second end of the second resistor is connected to the emitter of the second transistor, the first end of the second load is connected to the collector of the second transistor, the second end of the second load is connected to the negative electrode of the second power supply, and the base of the second transistor is connected to the controller;

[0008] The controller is in communication with the battery management system.

[0009] In a possible implementation manner of the first aspect, the second cooling control unit further includes a third resistor, wherein:

[0010] A first end of the third resistor is connected to the collector of the second transistor, and a second end of the third resistor is connected to the negative electrode of the second power supply.

[0011] In a possible implementation of the first aspect, the method further includes:

[0012] The confluence module is used to converge the cooling medium provided by the first load and the cooling medium provided by the second load.

[0013] In a possible implementation of the first aspect, the controller, the first cooling control unit, and the second cooling control unit are installed at the charging pile end or the vehicle end.

[0014] A second aspect of an embodiment of the present invention provides a battery pack pulse cooling control circuit, comprising a battery pack cooling control circuit and a capacitor, wherein:

[0015] A battery pack cooling control circuit is the battery pack cooling control circuit of the first aspect;

[0016] A first end of the capacitor is connected to the collector of the second transistor, and a second end of the capacitor is connected to the negative electrode of the second power supply.

[0017] A third aspect of the present invention provides a cooling control method for an electric vehicle battery pack. The method is implemented by the battery pack cooling control circuit of the first aspect of the present invention, or by the battery pack pulse cooling control circuit of the second aspect of the present invention, and includes:

[0018] Obtaining a temperature of the battery pack after being cooled for a first preset time under a charging condition or a discharging condition, to obtain a first cooled temperature;

[0019] determining whether the temperature after the first cooling is greater than a first temperature threshold, and if so, sending a first control signal to a controller to cause the controller to close the first transistor, so that the first power supply drives the first load to cool the battery pack, obtaining a temperature of the battery pack after driving the first load to cool the battery pack for a preset time, and obtaining a second temperature after cooling;

[0020] determining whether the temperature after the second cooling is greater than or equal to the first temperature threshold; if it is still greater than the first temperature threshold, sending a second control signal to the controller to cause the controller to close the second transistor, so that the second power supply inputs pulse power according to a preset duty cycle to drive the second load to cool the battery pack;

[0021] Obtain the temperature of the battery pack after driving the second load to pulse-cool the battery pack for a preset time, and obtain a third temperature after cooling. If the third temperature after cooling is less than the first temperature threshold and greater than the second temperature threshold, continue to cool the battery pack until the temperature of the battery pack is less than the second temperature threshold, and stop cooling.

[0022] In a possible implementation manner of the third aspect, before obtaining the first cooled temperature, the method includes:

[0023] Obtaining the temperature of the battery pack after charging or discharging for a second preset time to obtain the current temperature;

[0024] determining whether the current temperature is less than a first temperature threshold and greater than a second temperature threshold; if so, opening a valve of a liquid cooling plate at the bottom of the battery pack to cool the battery pack, and obtaining a temperature of the battery pack during a preset cooling time period, wherein the second temperature threshold is less than the first temperature threshold;

[0025] The temperature rise rate is calculated based on the temperature of the battery pack during the preset cooling time period. When the temperature rise rate is greater than 0, the valve body of the top liquid cooling plate of the battery pack is opened.

[0026] In a possible implementation of the third aspect, causing the second power supply to input pulse power according to a preset duty cycle to drive the second load to cool the battery pack includes:

[0027] determining whether the battery pack is in a charging condition or a discharging condition, and if in a charging condition, causing the second power supply to output pulse power according to a first preset duty cycle to drive the second load to perform pulse cooling on the battery pack;

[0028] If it is in the discharging condition, the second power supply is made to output pulse power according to a second preset duty cycle to drive the second load to perform pulse cooling on the battery pack.

[0029] In a possible implementation of the third aspect, after obtaining the first cooled temperature, the method further includes:

[0030] Determine whether the temperature after the first cooling is greater than the first temperature threshold. If so, send a third control signal to the controller to cause the controller to close the first transistor, so that the first power supply outputs power according to the preset frequency pulse signal to drive the first load to cool the battery pack.

[0031] In a possible implementation manner of the third aspect, the pulse cooling includes rectangular pulse cooling or sawtooth pulse cooling.

[0032] The technical solution of the present invention has the following advantages:

[0033] The battery pack cooling control circuit provided by the present invention comprises a controller, a first cooling control unit, a second cooling control unit and a battery management system, wherein the first cooling control unit includes a first power supply, a first transistor, a first resistor and a first load, and the second cooling control unit includes: a second power supply, a second transistor, a second load and a second resistor. By adopting a dual-path independent design of the first cooling control unit and the second cooling control unit, combined with the battery management system to cool the battery pack, the power consumption of the battery pack for additional cooling during fast charging is greatly reduced, thereby providing a cooling effect.

[0034] The battery pack pulse cooling control circuit provided by the present invention, by adding a capacitor in parallel to the first cooling control unit, can convert the rectangular power wave output by the first cooling control unit and the second cooling control unit into a sawtooth power wave, while improving the cooling effect and reducing the pressure in the flow channel.

[0035] The electric vehicle battery pack cooling control method provided by the present invention utilizes a battery management system to collect the temperature of the battery pack during cooling. If the temperature is greater than a first temperature threshold, the first cooling control unit is controlled to cool the battery pack. If the temperature of the battery pack after cooling is still greater than the first temperature threshold, the second cooling control unit is controlled to cool the battery pack, so that the output pulse power performs pulse cooling on the battery pack. Through this method, differential water flow is achieved, and the turbulence effect is increased, thereby greatly improving the heat exchange of the cooling medium and improving the cooling effect of the battery pack. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific implementation methods or the description of the prior art. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0037] Figure 1 1 is a circuit structure diagram of a battery pack cooling control circuit according to an embodiment of the present invention;

[0038] Figure 2 This is a connection diagram of the vehicle and charging pile cooling system of the battery pack cooling control circuit in an embodiment of the present invention;

[0039] Figure 3 This is a schematic diagram of the layout of the battery pack cooling control circuit in a vehicle and a charging pile in an embodiment of the present invention;

[0040] Figure 4 This is a diagram of the cooling cycle system architecture of the battery pack cooling control circuit in an embodiment of the present invention;

[0041] Figure 5 This is a dual-power rectangular pulse cooling power diagram of the battery pack cooling control circuit in an embodiment of the present invention;

[0042] Figure 6 This is a single power supply cooling circuit of the battery pack cooling control circuit in an embodiment of the present invention;

[0043] Figure 7 This is a single-power rectangular pulse cooling power diagram of the battery pack cooling control circuit in an embodiment of the present invention;

[0044] Figure 8 1 is a circuit structure diagram of a battery pack pulse cooling control circuit according to an embodiment of the present invention;

[0045] Figure 9 This is a dual-power sawtooth cooling power diagram of the battery pack pulse cooling control circuit in an embodiment of the present invention;

[0046] Figure 10 This is a single power sawtooth pulse cooling circuit diagram of a battery pack pulse cooling control circuit according to an embodiment of the present invention;

[0047] Figure 11 This is a single power supply sawtooth cooling power diagram of the battery pack pulse cooling control circuit in an embodiment of the present invention;

[0048] Figure 12 This is a flow chart of a cooling control method for an electric vehicle battery pack according to an embodiment of the present invention;

[0049] Figure 13 This is a flow chart of dual power pulse cooling control under charging conditions of a cooling control method for an electric vehicle battery pack according to an embodiment of the present invention;

[0050] Figure 14 This is a flow chart of dual power pulse cooling control under driving conditions of a cooling control method for an electric vehicle battery pack according to an embodiment of the present invention;

[0051] Figure 15This is a flow chart of single power pulse cooling control under charging conditions of a cooling control method for an electric vehicle battery pack according to an embodiment of the present invention;

[0052] Figure 16 This is a flow chart of single power pulse cooling control under driving conditions of a cooling control method for an electric vehicle battery pack according to an embodiment of the present invention;

[0053] The figures are marked as follows: 1. Charging pile; 2. High-voltage charging line; 3. Cooling pipeline; 4. Vehicle end; 43. Bottom liquid cooling plate; 44. Top liquid cooling plate; 45. Vehicle end cooling system connection joint; 46. Vehicle end charging joint; 47. Charging end cooling system connection joint; 100. Controller; 200. First cooling control unit; 300. Second cooling control unit; 400. Battery management system; 21. First power supply; 41. First transistor; 61. First resistor; 31. First load; 22. Second power supply; 42. Second transistor; 32. Second load; 62. Second resistor; 63. Third resistor; 50. Confluence module; 70. Capacitor. DETAILED DESCRIPTION

[0054] The technical features of the above embodiments can be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0055] In the description of the present invention, it should be noted that the terms "first", "second" and "third" are used for descriptive purposes only and should not be understood as indicating or implying relative importance.

[0056] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the term "connection" should be understood in a broad sense. For example, it can mean a fixed connection, a detachable connection, or an integral connection; it can mean a mechanical connection or an electrical connection; it can mean a direct connection or an indirect connection through an intermediate medium; it can mean internal communication between two components; it can mean a wireless connection or a wired connection. Those skilled in the art will be able to understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0057] The battery pack cooling control circuit provided by the embodiment of the present invention is as follows: Figure 1 As shown, it includes a controller 100, a first cooling control unit 200, a second cooling control unit 300 and a battery management system 400, wherein,

[0058] The first cooling control unit 200 includes: a first power supply 21, a first transistor 41, a first resistor 61, and a first load 31, wherein the positive electrode of the first power supply 21 is connected to the first end of the first resistor 61, the second end of the first resistor 61 is connected to the emitter of the first transistor 41, the collector of the first transistor 41 is connected to the first end of the first load 31, the second end of the first load 31 is connected to the negative electrode of the first power supply 21, and the base of the first transistor 41 is connected to the controller 100;

[0059] The second cooling control unit 300 includes: a second power supply 22, a second transistor 42, a second load 32, and a second resistor 62, wherein the positive electrode of the second power supply 22 is connected to the first end of the second resistor 62, the second end of the second resistor 62 is connected to the emitter of the second transistor 42, the first end of the second load 32 is connected to the collector of the second transistor 42, the second end of the second load 32 is connected to the negative electrode of the second power supply 22, and the base of the second transistor 42 is connected to the controller 100;

[0060] The controller 10 is in communication with the battery management system.

[0061] In this embodiment, a complete cooling cycle system is formed by connecting the vehicle's cooling system and the charging pile's cooling system. Figure 2 and Figure 3 As shown, from Figure 2 and Figure 3 As can be seen, the vehicle end 4 and the charging pile 1 are connected through the cooling pipe 3 and the high-voltage charging line 2. A bottom liquid cooling plate 43 is provided on the battery pack in the vehicle end 4, a top liquid cooling plate 44 is provided at the bottom, and a vehicle end cooling system connection joint 45, a vehicle end charging joint 46, and a charging end cooling system connection joint 47 are provided in the middle of the cooling pipe.

[0062] A corresponding battery pack cooling control circuit is designed for the cooling cycle system to control the cooling cycle system. When the battery pack is in driving condition, the battery management system collects the temperature information of the battery pack and sends a control signal to the vehicle controller. The vehicle controller controls the vehicle-side cooling cycle system to cool the battery pack. When in charging condition, the battery management system collects the temperature information of the battery pack and sends a control signal to the charging pile. The control unit of the charging pile controls the cooling cycle system and cools the battery pack. The cooling cycle system architecture diagram is shown in the figure below. Figure 4 As shown, the control unit of the charging pile communicates with the battery management system and the vehicle controller, and controls the charging unit and the cooling unit by receiving the signal from the battery management system, so that the flow rate of the cooling medium is adjusted.

[0063] The battery pack cooling control circuit has dual power sources, namely a first power source 21 and a second power source 22, which respectively power two loads. Specifically, the battery pack cooling control circuit includes a controller 100, a first cooling control unit 200, a second cooling control unit 300, and a battery management system 400. The first power source 21 is located in the first cooling control unit. The first cooling control unit also includes a first transistor 41, a first resistor 61, and a first load 31. The connections between the various components are as follows: the positive electrode of the first power source 21 is connected to the first end of the first resistor 61, the second end of the first resistor 61 is connected to the emitter of the first transistor 41, the collector of the first transistor 41 is connected to the first end of the first load 31, the second end of the first load 31 is connected to the negative electrode of the first power source 21, and the base of the first transistor 41 is connected to the controller 100. When only the first power source 21 is operating, a continuous and stable power output is generated, and the flow rate of the cooling medium is also stable.

[0064] The second power supply 22 is located in the second cooling control unit 300, and the second cooling control unit 300 also includes a second transistor 42, a second load 32, and a second resistor 62. The connection between the various components is as follows: the positive electrode of the second power supply 22 is connected to the first end of the second resistor 62, the second end of the second resistor 62 is connected to the emitter of the second transistor 42, the first end of the second load 32 is connected to the collector of the second transistor 42, the second end of the second load 32 is connected to the negative electrode of the second power supply 22, and the base of the second transistor 42 is connected to the controller 100. When the second power supply 2 is intermittently supplied with power by the interruption of the second transistor 42, it can work together with the first power supply 21 to generate rectangular pulse-type power, such as Figure 5 As shown, the flow rate of the cooling medium is affected by the power to produce a pulse flow state. During the process of cooling the fluid in the form of pulses, the heat transfer effect of the boundary layer can be effectively improved, the heat transfer speed can be increased, and the cooling can be accelerated.

[0065] When the fluid is cooled in a pulsed manner, a velocity difference occurs between the high and low flow rates during the pulse process. The two fluids are subjected to mutual forces. Due to their large specific heat capacity, the temperature of the central fluid is low, while the temperature of the fluids in contact with the top and bottom liquid cooling plates is high, resulting in a temperature gradient. Therefore, under the action of the pulse, the high-flow rate impacts the low-flow rate fluid, mixing the temperatures and effectively improving the uniform temperature within the package. The thermal conductivity of water is 0.6W / (m·K), while the thermal conductivity of aluminum is 237W / (m·K). During the cooling and heat exchange process, the bottleneck of heat exchange is the slow heat conduction rate of liquid cooling. Therefore, cooling under the action of pulses can bring the coolant in the low-temperature center zone into contact with the flow channel walls. Due to the increased temperature difference, the heat transfer effect is further improved compared to traditional cooling solutions with a steady flow rate.

[0066] It should be noted that the first transistor 41 and the second transistor 42 function as transistors and can achieve a pulse effect by changing the voltage of the P wave output by the battery management system.

[0067] It should be noted that the battery pack cooling control circuit can also use only one power supply to power the cooling cycle system. Figure 6 As shown, Figure 6 For a single power supply cooling circuit, the cooling cycle system is powered by only one power supply to output the power required by the cooling cycle system. The single power supply has the maximum continuous power, and the flow rate of the cooling medium is also at its maximum. The MCU in the battery management system outputs a P wave which is transmitted to the controller 100 via a CAN signal, and then controls the second transistor 42 to change the power level to achieve a rectangular pulse cooling effect, such as Figure 7 As shown, this method can reduce energy consumption and greatly improve the heat exchange of the cooling medium.

[0068] In one embodiment, the second cooling control unit 300 further includes a third resistor 63, wherein:

[0069] A first end of the third resistor 63 is connected to the collector of the second transistor 42 , and a second end of the third resistor 63 is connected to the negative electrode of the second power supply 22 .

[0070] In this embodiment, a third resistor 63 is further connected in parallel to the second cooling control unit 300 to control the magnitude of the current flowing into the second load 32 , thereby adjusting the peak value of the rectangular pulse.

[0071] It should be noted that the third resistor 63 is a variable resistor, and its resistance value can be dynamically adjusted.

[0072] In one embodiment, the confluence module 50 is used to combine the cooling medium provided by the first load 31 and the cooling medium provided by the second load 32 .

[0073] In this embodiment, the battery pack cooling control circuit also includes a confluence module 50, which can combine the cooling medium provided by the first load 31 with the cooling medium provided by the second load 32. Specifically, when the first power supply 21 is operating and the second power supply 22 is also turned on, the second power supply 22 generates intermittent flow rate to the confluence module by supplying power to the second load 32, achieving pulse cooling in the form of rectangular pulses or sawtooth pulses.

[0074] In one embodiment, the controller 100 , the first cooling control unit 200 , and the second cooling control unit 300 are installed at the charging station or the vehicle.

[0075] In this embodiment, the controller 100, the first cooling control unit 200, and the second cooling control unit 300 can be installed on the charging pile or the vehicle. If installed on the charging pile, the controller 100 is the controller of the charging pile. If installed on the vehicle, the controller 100 is the vehicle controller.

[0076] To solve the same technical problem, the battery pack pulse cooling control circuit provided by the embodiment of the present invention is as follows: Figure 8 As shown, the battery pack cooling control circuit and capacitor 70, wherein,

[0077] The battery pack cooling control circuit is such as the battery pack cooling control circuit of this embodiment;

[0078] A first end of the capacitor 70 is connected to the collector of the second transistor 42 , and a second end of the capacitor 70 is connected to the negative electrode of the second power supply 22 .

[0079] In this embodiment, based on the battery pack cooling control circuit, a capacitor 70 is connected in parallel to the second cooling control unit 300 to convert the rectangular wave into a sawtooth-shaped power wave. The power acts on the cooling circulation system, producing a similar sawtooth-like flow pattern. This effect is similar to rectangular pulse cooling, but reduces the pressure within the flow channel. Specifically, the first end of capacitor 70 is connected to the collector of the second transistor 42, and the second end of capacitor 70 is connected to the negative electrode of the second power source 22.

[0080] The sawtooth power diagram is as follows Figure 9 As shown, since the rectangular pulse mode is suitable for commercial vehicles with a large pressure load on the cold plate, a capacitor is introduced into the second cooling control unit 300 to generate a sawtooth pulse, which is suitable for cold plates that can withstand a large pressure load in a short time.

[0081] It should be noted that the capacitor 70 connected in parallel in the second cooling control unit 300 can be set in a dual power supply cooling cycle system scenario, or can be set in a single power supply cooling cycle system scenario, such as Figure 10 As shown, Figure 10 It is a single power supply sawtooth pulse cooling circuit. A capacitor is connected in parallel or an inductor is connected in series on the basis of the single power supply cooling circuit to produce sawtooth pulse cooling and improve the heat transfer effect. Its power diagram is as follows Figure 11 shown.

[0082] To solve the same technical problem, an embodiment of the present invention provides a cooling control method for an electric vehicle battery pack, as follows: Figure 12 As shown, Figure 12 This is a flow chart of a cooling control method for an electric vehicle battery pack, including steps S121 to S124. The specific steps are as follows:

[0083] S121. Obtaining a temperature of the battery pack after being cooled for a first preset time under a charging condition or a discharging condition, to obtain a first cooled temperature;

[0084] In this embodiment, the battery management system is used to collect the temperature of the battery pack after it is cooled for a first preset time under charging conditions or discharging conditions to obtain the first cooled temperature. It can be understood that when cooling the battery pack, its conditions can be divided into charging conditions and operating conditions. If it is under charging conditions, the cooling process is as follows Figure 13 As shown, during the initial charging phase, the battery management system monitors the temperature of the entire battery pack in real time. If it detects that the battery pack temperature is greater than a second temperature threshold, it begins cooling the battery pack and continuously monitors the battery pack temperature to obtain a first cooled temperature. The first preset cooling time can be understood as a fixed duration (e.g., 1s, 5s, 10s, etc.) set manually when collecting the first cooled temperature, and can be set according to actual needs.

[0085] If it is in the operating condition, during the driving stage, the cooling process is as follows Figure 14 As shown, the battery management system adopts the same strategy as the above-mentioned charging condition, that is, monitoring the temperature of the entire battery pack. If it is detected that the temperature of the battery pack is greater than the second temperature threshold, the battery pack is cooled and the temperature of the battery pack is continuously monitored to obtain the first cooled temperature.

[0086] In one embodiment, before obtaining the first cooled temperature, the process includes:

[0087] Obtaining the temperature of the battery pack after charging or discharging for a second preset time to obtain the current temperature;

[0088] determining whether the current temperature is less than a first temperature threshold and greater than a second temperature threshold; if so, opening a valve of a liquid cooling plate at the bottom of the battery pack to cool the battery pack, and obtaining a temperature of the battery pack during a preset cooling time period, wherein the second temperature threshold is less than the first temperature threshold;

[0089] The temperature rise rate is calculated based on the temperature of the battery pack during the preset cooling time period. When the temperature rise rate is greater than 0, the valve body of the top liquid cooling plate of the battery pack is opened.

[0090] In this embodiment, during charging, at the initial charging stage, the battery management system monitors the temperature of the entire battery pack in real time to obtain the current temperature. When the current battery pack temperature is low, i.e., below a second temperature threshold, the battery management system controls the three-way valve to close and simultaneously inputs a signal to the charging pile, disabling cooling. If the current temperature is greater than the second temperature threshold and less than the first temperature threshold, a signal is sent to open the battery pack liquid cooling plate. Specifically, the valve of the bottom liquid cooling plate of the battery pack is opened to cool the battery pack. While the battery pack is cooling, the battery pack temperature is monitored in real time. If the monitored battery pack temperature rise rate is greater than 0 and the battery voltage has not reached the charge cutoff voltage, the valve of the top liquid cooling plate of the battery pack is opened, allowing both the bottom and top liquid cooling plates to cool the battery pack simultaneously.

[0091] If it is in operating conditions, when driving, the battery management system also takes the same operations as mentioned above under charging conditions, which will not be repeated here. The difference is that the battery management system inputs the signal into the vehicle end.

[0092] It should be noted that the second temperature threshold is lower than the first temperature threshold, and the second preset cooling time can be understood as: when the battery pack is in the initial stage of charging or after a manually set time of driving (for example, 1s, 5s, 10s, etc.), it can be set according to actual needs.

[0093] S122. Determine whether the temperature after the first cooling is greater than a first temperature threshold. If so, send a first control signal to the controller to cause the controller to close the first transistor, so that the first power supply drives the first load to cool the battery pack, obtain the battery pack temperature after driving the first load to cool the battery pack for a preset time, and obtain the second temperature after cooling.

[0094] In this embodiment, whether under charging conditions or driving conditions, if the first cooling temperature is greater than the first temperature threshold, the battery management system sends a first control signal to the controller 100. After the controller 100 closes the first transistor 41, the first power supply 21 starts working and drives the first load 61 to cool the battery pack. After a period of time, that is, after the preset cooling time, the battery management system re-detects the temperature and obtains the second cooling temperature.

[0095] It should be noted that the first control signal refers to a control signal sent by the battery management system to the first transistor 41 or the second transistor 42 in the battery pack cooling control circuit with dual power supplies.

[0096] S123. Determine whether the temperature after the second cooling is greater than or equal to the first temperature threshold. If it is still greater than the first temperature threshold, send a second control signal to the controller to cause the controller to close the second transistor, so that the second power supply inputs pulse power according to a preset duty cycle to drive the second load to cool the battery pack.

[0097] In this embodiment, after obtaining the second cooled temperature, when dual power supplies are used to power the cooling system, if the second cooled temperature is greater than the first temperature threshold, the battery management system outputs a signal to the charging station or vehicle via the CAN bus, causing the charging station or vehicle to close the second transistor 42 and supply power through the second power supply 62. Specifically, the switching frequency of the second transistor 42 is output according to a preset duty cycle, so that the second power supply 62 generates an intermittent flow rate by supplying power to the second load 32, thereby achieving pulsed cooling (rectangular pulses or sawtooth pulses) in the confluence module.

[0098] In one embodiment, the second power supply is caused to input pulse power according to a preset duty cycle to drive the second load to cool the battery pack, including:

[0099] determining whether the battery pack is in a charging condition or a discharging condition, and if in a charging condition, causing the second power supply to output pulse power according to a first preset duty cycle to drive the second load to perform pulse cooling on the battery pack;

[0100] If it is in the discharging condition, the second power supply is made to output pulse power according to a second preset duty cycle to drive the second load to perform pulse cooling on the battery pack.

[0101] In this embodiment, if the battery pack is in a charging state, the second power supply is caused to output pulse power according to a first preset duty cycle to drive the second load to perform pulse cooling on the battery pack, wherein the first preset duty cycle is set to 0% to 70%.

[0102] If it is in the discharging condition, the second power supply is made to output pulse power according to a second preset duty cycle to drive the second load to perform pulse cooling on the battery pack, wherein the second preset duty cycle is set to 20% to 80%.

[0103] In one embodiment, after obtaining the first cooled temperature, the method further includes:

[0104] Determine whether the temperature after the first cooling is greater than the first temperature threshold. If so, send a third control signal to the controller to cause the controller to close the first transistor, so that the first power supply outputs power according to the preset frequency pulse signal to drive the first load to cool the battery pack.

[0105] In this embodiment, after obtaining the first cooled temperature, a single power supply can also be used to power the cooling system. Specifically, when in the charging state, such as Figure 15 As shown, if the temperature after the first cooling is greater than the first temperature threshold, the battery management system outputs a P wave signal to the charging pile to control the change amplitude of the second transistor 42 to achieve single power pulse cooling.

[0106] When in driving state, Figure 16As shown, if the temperature after the first cooling is greater than the first temperature threshold, the battery management system outputs a P wave signal to the vehicle end to control the change amplitude of the second transistor 42 to achieve single power pulse cooling.

[0107] It should be noted that the third control signal can be understood as a signal that can enable the controller to close the first transistor, so that the first power supply outputs power according to the preset frequency pulse signal to drive the first load to cool the battery pack. The preset frequency pulse signal can be understood as a P-wave signal.

[0108] In one embodiment, the pulse cooling includes rectangular pulse cooling or sawtooth pulse cooling.

[0109] In this embodiment, pulse cooling includes rectangular pulse cooling or sawtooth pulse cooling. Rectangular pulse cooling is achieved through the dual power supply in the battery pack cooling control circuit. It can also be achieved by the battery management system in the single power supply cooling circuit outputting a P-wave signal to the vehicle end to control the change amplitude of the second transistor 42.

[0110] Sawtooth pulse cooling can be achieved by connecting a capacitor 70 in parallel in the second cooling control unit 300 to convert the rectangular wave into a sawtooth power wave. It can also be achieved by connecting a capacitor in parallel or an inductor in series on the basis of a single power supply cooling circuit to generate sawtooth pulse cooling.

[0111] S124. Obtain the temperature of the battery pack after driving the second load to pulse-cool the battery pack for a preset time, and obtain a third temperature after cooling. If the third temperature after cooling is less than the first temperature threshold and greater than the second temperature threshold, continue to cool the battery pack until the temperature of the battery pack is less than the second temperature threshold, and stop cooling.

[0112] In this embodiment, regardless of charging or driving conditions, after the second power source 62 generates an intermittent flow rate through the confluence module to achieve pulse cooling by supplying power to the second load 32, the battery pack temperature is continuously monitored to obtain a third post-cooling temperature. If the third post-cooling temperature is less than the first temperature threshold, a further determination is made to determine whether it is less than the second temperature threshold. If it is still greater than the second temperature threshold, pulse cooling of the battery pack continues. If it is less than the second temperature threshold, a signal is output to shut down the bottom and top liquid cooling plates, and power to the cooling system on the vehicle or charging station is simultaneously shut down.

[0113] After a period of time, the battery management system re-checks the battery pack temperature to identify whether the vehicle is powered off, the battery voltage has reached the charging cut-off SOC, or charging has been manually stopped. If not, the battery pack temperature is re-evaluated. If so, the entire battery pack stops supplying power.

[0114] The specific embodiments described above further illustrate the objectives, technical solutions, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the scope of protection of the present invention. In particular, it should be noted that any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included within the scope of protection of the present invention for those skilled in the art.

Claims

1. A battery pack cooling control circuit, characterized in that: The invention comprises a controller (100), a first cooling control unit (200), a second cooling control unit (300) and a battery management system (400), wherein: The first cooling control unit (200) comprises: a first power supply (21), a first transistor (41), a first resistor (61) and a first load (31), wherein the positive electrode of the first power supply (21) is connected to the first end of the first resistor (61), the second end of the first resistor (61) is connected to the emitter of the first transistor (41), the collector of the first transistor (41) is connected to the first end of the first load (31), the second end of the first load (31) is connected to the negative electrode of the first power supply (21), and the base of the first transistor (41) is connected to the controller (100); The second cooling control unit (300) comprises: a second power supply (22), a second transistor (42), a second load (32) and a second resistor (62), wherein the positive electrode of the second power supply (22) is connected to the first end of the second resistor (62), the second end of the second resistor (62) is connected to the emitter of the second transistor (42), the first end of the second load (32) is connected to the collector of the second transistor (42), the second end of the second load (32) is connected to the negative electrode of the second power supply (22), and the base of the second transistor (42) is connected to the controller (100); The controller (10) is in communication connection with the battery management system.

2. The battery pack cooling control circuit according to claim 1, wherein: The second cooling control unit (300) further includes a third resistor (63), wherein: The first end of the third resistor (63) is connected to the collector of the second transistor (42), and the second end of the third resistor (63) is connected to the negative electrode of the second power supply (22).

3. The battery pack cooling control circuit according to claim 1, wherein: Also includes: A confluence module (50) is used to converge the cooling medium provided by the first load (31) and the cooling medium provided by the second load (32).

4. The battery pack cooling control circuit according to claim 1, wherein: The controller (100), the first cooling control unit (200) and the second cooling control unit (300) are installed at the charging pile end or the vehicle end.

5. A battery pack pulse cooling control circuit, characterized in that: It includes a battery pack cooling control circuit and a capacitor (70), wherein: The battery pack cooling control circuit is a battery pack cooling control circuit according to any one of claims 1 to 4; The first end of the capacitor (70) is connected to the collector of the second transistor (42), and the second end of the capacitor (70) is connected to the negative electrode of the second power supply (22).

6. A cooling control method for an electric vehicle battery pack, characterized in that: The method is implemented by the battery pack cooling control circuit according to any one of claims 1 to 4, or by the battery pack pulse cooling control circuit according to claim 5, including: Obtaining a temperature of the battery pack after being cooled for a first preset time under a charging condition or a discharging condition, to obtain a first cooled temperature; determining whether the first cooled temperature is greater than a first temperature threshold, and if so, sending a first control signal to the controller to cause the controller to close the first transistor, so that the first power supply drives the first load to cool the battery pack, and obtaining a temperature of the battery pack after driving the first load to cool the battery pack for a preset time, thereby obtaining a second cooled temperature; determining whether the temperature after the second cooling is greater than or equal to the first temperature threshold, and if it is still greater than the first temperature threshold, sending a second control signal to the controller to cause the controller to close the second transistor, so that the second power supply inputs pulse power according to a preset duty cycle to drive the second load to cool the battery pack; Obtain the temperature of the battery pack after driving the second load to pulse-cool the battery pack for a preset time, and obtain a third temperature after cooling. If the third temperature after cooling is less than the first temperature threshold and greater than the second temperature threshold, continue to cool the battery pack until the temperature of the battery pack is less than the second temperature threshold, and stop cooling.

7. The electric vehicle battery pack cooling control method according to claim 6, characterized in that: Before obtaining the first cooled temperature, the method comprises: Obtaining the temperature of the battery pack after charging or discharging for a second preset time to obtain a current temperature; determining whether the current temperature is less than the first temperature threshold and greater than the second temperature threshold; if so, opening a valve of a bottom liquid cooling plate of the battery pack to cool the battery pack, and obtaining a temperature of the battery pack within a preset cooling time period, wherein the second temperature threshold is less than the first temperature threshold; The temperature rise rate is calculated according to the temperature of the battery pack during the preset cooling time period. When the temperature rise rate is greater than 0, the valve body of the top liquid cooling plate of the battery pack is opened.

8. The electric vehicle battery pack cooling control method according to claim 6, characterized in that: The step of causing the second power supply to input pulse power according to a preset duty cycle to drive the second load to cool the battery pack includes: determining whether the battery pack is in a charging condition or a discharging condition, and if in the charging condition, causing the second power supply to output pulse power according to a first preset duty cycle to drive the second load to perform pulse cooling on the battery pack; If it is in the discharging condition, the second power supply is made to output pulse power according to a second preset duty cycle to drive the second load to perform pulse cooling on the battery pack.

9. The electric vehicle battery pack cooling control method according to claim 6, wherein: After obtaining the first cooled temperature, the method further comprises: Determine whether the temperature after the first cooling is greater than the first temperature threshold. If so, send a third control signal to the controller to cause the controller to close the first transistor, so that the first power supply outputs power according to a preset frequency pulse signal to drive the first load to cool the battery pack.

10. The electric vehicle battery pack cooling control method according to claim 8, wherein: The pulse cooling includes rectangular pulse cooling or sawtooth pulse cooling.

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