Temperature control method and system for high-voltage electrical box

Abstract

The invention provides a high-voltage electric appliance box temperature control method and system, and belongs to the technical field of high-voltage electric appliance boxes. Comprising the following steps that temperature sensors are arranged at the positions of copper bars at contact points of relays respectively, and real-time temperature information is sent to a BMS end; a high-voltage loop of the BDU is electrically connected with the battery pack; in the discharging process, the main positive relay and the main negative relay are closed to provide power for the motor, the temperature sensor obtains the first real-time temperature and the second real-time temperature of the contact copper bar, the first actual temperature rise rate is combined and compared with a plurality of discharging temperature threshold values and a first temperature rise rate threshold value, and a power reduction discharging strategy of the discharging process is executed; in the charging process, the fast charging relay and the main negative relay are closed, the battery pack is charged, the temperature sensor obtains the third real-time temperature and the fourth real-time temperature of the copper bar, the third real-time temperature and the fourth real-time temperature are combined with the second actual temperature rise rate and are compared with a plurality of charging temperature threshold values and a second temperature rise rate threshold value, and the current reduction charging strategy of the charging process is executed.

Description

Technical Field

[0001] This invention relates to the field of high-voltage electrical box technology, and in particular to a high-voltage electrical box temperature control method and system. Background Technology

[0002] The high-voltage electrical box (BDU) for new energy power batteries is one of the core components of the high-voltage system in electric vehicles, directly affecting the distribution and safety of electrical energy. It not only efficiently and rationally distributes the high-voltage energy output from the battery to key electrical equipment such as the drive motor, air conditioning compressor, and charger, but also uses fuses, relays, pre-charge circuits, and sensors to monitor overcurrent, short circuits, insulation, and isolate faults. Therefore, the BDU is both the "central hub" of the vehicle's high-voltage energy and a "barrier" for safety protection. Its reliability and intelligence level directly determine the stable operation of the power battery system, thus affecting the vehicle's performance, safety, and lifespan. The BDU faces multiple challenges in application. First, as the voltage platform of new energy vehicles gradually develops from 400V to 800V or even higher, the requirements for insulation and withstand voltage significantly increase. Simultaneously, the internal integration of the electrical box is becoming increasingly higher, placing higher demands on space layout and heat dissipation. Third, long-term operation under high voltage, high current, and complex environments severely tests the reliability and lifespan of components. Finally, how to ensure safety while simultaneously achieving high performance, low cost, and intelligence requires continuous optimization at the technological and industrial levels.

[0003] Therefore, it is essential to provide a high-voltage electrical box temperature control method and system that monitors the temperature status of key components in the high-voltage electrical box and executes corresponding temperature control strategies to ensure the safety of the battery pack and the entire vehicle. Summary of the Invention

[0004] In view of this, the present invention proposes a high-voltage electrical box temperature control method and system that can detect the real-time temperature of multiple copper busbars and quickly reduce the discharge power or charging current when the real-time temperature is abnormal or the temperature rise is abnormal, thereby improving the reliability of BDU use.

[0005] On one hand, the present invention provides a method for temperature control of a high-voltage electrical box, comprising the following steps: S1: Temperature sensors are installed at the copper busbars of the fast charging relay, main positive relay and main negative relay contacts of the BDU. The temperature sensors send real-time temperature information to the BMS terminal through the wiring harness; the high voltage circuit of the BDU is electrically connected to the battery pack. S2: During the discharge process, the main positive relay and the main negative relay of the BDU close, providing power to the motor. The temperature sensor obtains the first real-time temperature of the contact copper busbars of the main positive relay and the main negative relay. T 1 and second real-time temperature T 2. Combined with the first real-time temperature T1 or second real-time temperature T The first actual temperature rise rate of 2 is compared with several discharge temperature thresholds and the first temperature rise rate threshold, and the BMS terminal executes a power reduction discharge strategy for the discharge process. S3: During charging, the fast charging relay and main negative relay of the BDU close to charge the battery pack. The temperature sensor obtains the third real-time temperature of the contact copper busbars of the fast charging relay and main negative relay. T 3 and 4 real-time temperatures T 4. Combined with the third real-time temperature T 3 or 4 real-time temperature T The second actual temperature rise rate of 4 is compared with several charging temperature thresholds and the second temperature rise rate threshold, and the BMS terminal executes a current reduction charging strategy during the charging process.

[0006] Based on the above technical solution, preferably, step S2 includes: setting several discharge temperature thresholds, with the first discharge temperature threshold, the second discharge temperature threshold, the third discharge temperature threshold, and the fourth temperature threshold increasing sequentially; the first real-time temperature... T 1 or second real-time temperature T The larger of 2 is the real-time discharge temperature. Combined with the first actual temperature rise rate, the following power reduction discharge strategy is set for the discharge process: 1) When the real-time discharge temperature does not exceed the first discharge temperature threshold, regardless of the magnitude of the first actual temperature rise rate, the output power of the battery pack is the first output power. P 1; 2) When the real-time discharge temperature exceeds the first discharge temperature threshold but does not exceed the second discharge temperature threshold, regardless of the magnitude of the first actual temperature rise rate, in the first time... t Within 1, the battery pack output power will be reduced from the first output power. P 1 is reduced to the second output power P 2;3) When the real-time discharge temperature exceeds the second discharge temperature threshold but does not exceed the third discharge temperature threshold, regardless of the magnitude of the first actual temperature rise rate, at the second time... t Within 2, the battery pack output power will be changed from the second output power. P 2 is reduced to the third output power P 3; 4) When the real-time discharge temperature exceeds the third discharge temperature threshold but does not exceed the fourth discharge temperature threshold, if the first actual temperature rise rate is less than the first temperature rise rate threshold, at the third time... t Within 3, the battery pack output power will be reduced from the third output power. P 3 is reduced to the fourth output power P 4; 5) When the real-time discharge temperature exceeds the third discharge temperature threshold but does not exceed the fourth discharge temperature threshold, if the first actual temperature rise rate exceeds the first temperature rise rate threshold, then at the fourth time... t 4. The battery pack output power will be reduced from the third output power. P3 was reduced to the fifth highest output power. P 5; 6) If the actual temperature exceeds the fourth discharge temperature threshold, and after reducing the output power in cases 2), 3), 4), or 5) of the above-mentioned power reduction discharge strategy, the first actual temperature rise rate still exceeds the first temperature rise rate threshold and remains there for more than 10 seconds, or the interval between two consecutive power reductions does not exceed 30 seconds, then at the fifth time... t Within 5 days, the current output power will be reduced to 0. In the above strategy... t 1> t 2> t 3> t 4> t 5; and the output power meets the requirements. P 1> P 2> P 3> P 4> P 5.

[0007] Preferably, the output power of the battery pack is calculated based on the derating ratio, the current discharge voltage, the rated current, the influence of ambient temperature, the influence of aging, or the influence of voltage.

[0008] Preferably, the first time t 1 is 30 seconds; the second time t 2 is 20 seconds; third time t 3 is 10 seconds; fourth time t 4 is 5 seconds; the fifth time t 5 represents 1 second.

[0009] Preferably, the first temperature rise rate threshold is 1℃ / s.

[0010] A further preferred embodiment includes step S3, which involves setting several charging temperature thresholds, with the first, second, third, and fourth charging temperature thresholds increasing sequentially, and the third real-time temperature... T 3 or 4 real-time temperature T The larger of 4 is the real-time charging temperature. Combined with the second actual temperature rise rate, the following current-reducing charging strategy is set for the charging process: 1) When the real-time charging temperature does not exceed the first charging temperature threshold, regardless of the magnitude of the second actual temperature rise rate, the rated current is applied. 1) Charging; 2) When the real-time charging temperature exceeds the first charging temperature threshold but does not exceed the second charging temperature threshold, regardless of the magnitude of the second actual temperature rise rate, at the sixth time... t Within 6 hours, the current charging current will be linearly reduced from the rated current to the first charging current. I 1;3) When the real-time charging temperature exceeds the second charging temperature threshold but does not exceed the third charging temperature threshold, regardless of the magnitude of the second actual temperature rise rate, at the seventh time...t Within 7 days, the current charging current will be changed from the first charging current. I 1. Adjust to the second charging current I 2;4) When the actual charging temperature exceeds the third charging temperature threshold but does not exceed the fourth temperature threshold, if the second actual temperature rise rate is less than the second temperature rise rate threshold, then at the eighth time... t Within 8 days, the current charging current will be changed from the second charging current. I 2. Adjust to the third charging current I 3;5) When the actual charging temperature exceeds the third charging temperature threshold but does not exceed the fourth temperature threshold, if the second actual temperature rise rate exceeds the second temperature rise rate threshold, then at the ninth time... t Within 9 minutes, the current charging current will be changed from the second charging current. I 2. Adjust to the fourth charging current I 4; 6) If the actual charging temperature exceeds the fourth temperature threshold, and after reducing the charging current in cases 2), 3), 4), or 5) of the above-mentioned current reduction charging strategy, the second actual temperature rise rate still exceeds the second temperature rise rate threshold and remains there for more than 10 seconds, or the interval between two consecutive stages of reducing the charging current does not exceed 30 seconds, then at the tenth time... t Within 10 minutes, the current charging current will be reduced to 0; among which... t 6> t 7> t 8> t 9> t 10; .

[0011] More preferably, the first charging current I 1 is obtained by linearly decreasing the rated current; the second charging current. I 2 refers to the first charging current I The third charging current was obtained by a linear decreasing method. I 3 refers to the second charging current I The fourth charging current was obtained by a linear decreasing method. I 4 refers to the third charging current I 3. Obtained through a linear descent method.

[0012] More preferably, the sixth time t 6 is 10 seconds; the seventh time t 7 is 10 seconds; the eighth time t 8 is 10 seconds; the ninth time t 9 is 5 seconds; the tenth time t 10 equals 1 second.

[0013] More preferably, the second temperature rise rate threshold is 1℃ / s.

[0014] On the other hand, the present invention also provides a high-voltage electrical box temperature control system for implementing the above-mentioned method, characterized in that it includes: BDU is used for electrical connection to a battery pack, motor, or charging device; The relay unit further includes a fast-charging relay, a main positive relay, and a main negative relay disposed within the BDU, with temperature sensors arranged at the contact point copper busbars of each relay. The BMS is electrically connected to the relay unit and the temperature sensor respectively; during the discharge process, the BDU selectively executes a power reduction discharge strategy based on the temperature of the contact copper busbars of the main positive relay and the main negative relay and the current value of the first actual temperature rise rate; or during the charging process, it obtains the temperature of the contact copper busbars of the fast charging relay and the main negative relay and the current value of the second actual temperature rise rate, and selectively executes a current reduction charging strategy.

[0015] The present invention provides a high-voltage electrical box temperature control method and system, which, compared with the prior art, has the following advantages: 1. This solution simultaneously monitors the real-time temperature and temperature rise rate of the relay contact copper busbar, and adopts a graded strategy during discharge. When the temperature rise is slow or does not exceed the specified threshold, power reduction measures are not triggered to avoid unnecessary derating. When the temperature rise rate is abnormal or the real-time temperature exceeds the set temperature threshold, the output power is reduced in a stepwise manner to avoid vehicle jerking. 2. When implementing the power reduction strategy, the battery aging degree, dynamic discharge voltage, and ambient temperature compensation items related to the number of cycles and mileage are fully considered to make the power control more accurate and avoid the risk of output overload. 3. During charging, the real-time temperature and temperature rise rate of the corresponding relay contact copper busbar are also monitored. A four-level stepped current regulation method is adopted. For abnormal real-time temperature or temperature rise rate, a linear decrease and smooth transition method is adopted to avoid charging interruption. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a flowchart illustrating a high-voltage electrical box temperature control method and system according to the present invention. Figure 2 This is a temperature control logic diagram of the BDU of a high-voltage electrical box temperature control method and system according to the present invention; Figure 3This is an electrical schematic diagram of a high-voltage electrical box temperature control method and system according to the present invention. Detailed Implementation

[0018] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0019] As the integration density of BDUs (Browser Ducts) increases, higher demands are placed on space layout and heat dissipation. Long-term operation under high voltage, high current, and complex environments poses a severe test to the reliability and lifespan of components. Therefore, such as... Figure 1 Combination Figure 2 As shown, in one aspect, the present invention provides a high-voltage electrical box temperature control method, comprising the following steps: S1: Temperature sensors are installed at the copper busbars of the fast charging relay, main positive relay, and main negative relay contacts of the BDU. The temperature sensors transmit real-time temperature information to the BMS terminal through the wiring harness. The high-voltage circuit of the BDU is electrically connected to the battery pack. like Figure 3 As shown in the diagram, the relays include a fast-charging positive relay, a fast-charging negative relay, a main positive relay, a main negative relay, and a pre-charge relay. During discharge, the pre-charge relay activates first, raising the voltage on the load side. The main positive and main negative relays then activate, forming a circuit with the battery pack and the discharge terminal to supply power to the load, such as a motor. To avoid excessive voltage differences, a large capacitor is usually included. The pre-charge relay can pre-charge this capacitor, reducing the voltage difference between the load and the battery pack. When the battery pack needs charging, the fast-charging positive relay, fast-charging negative relay, main positive relay, and main negative relay all activate, and the BDU connects the charging equipment to the battery pack.

[0020] The temperature sensor can be set Figure 3 The circled "+" symbol indicates the temperature of each relay contact. Examples include the markings at FC+ for the fast-charging positive relay, BAT+ and PRE+ at both ends of the main positive relay, and BAT- and PRE- at both ends of the main negative relay.

[0021] S2: During the discharge process, the main positive relay and the main negative relay of the BDU close, providing power to the motor. The temperature sensor obtains the first real-time temperature of the contact copper busbars of the main positive relay and the main negative relay. T 1 and second real-time temperature T 2. Combined with the first real-time temperature T 1 or second real-time temperature TThe first actual temperature rise rate of 2 is compared with several discharge temperature thresholds and the first temperature rise rate threshold, and the BMS terminal executes a power reduction discharge strategy for the discharge process.

[0022] Step S2 involves setting several discharge temperature thresholds, with the first, second, third, and fourth discharge temperature thresholds increasing sequentially; the first real-time temperature... T 1 or second real-time temperature T The larger of 2 is the real-time discharge temperature. Combined with the first actual temperature rise rate, the following power reduction discharge strategy is set for the discharge process: 1) When the real-time discharge temperature does not exceed the first discharge temperature threshold, regardless of the magnitude of the first actual temperature rise rate, the output power of the battery pack is the first output power. P 1; 2) When the real-time discharge temperature exceeds the first discharge temperature threshold but does not exceed the second discharge temperature threshold, regardless of the magnitude of the first actual temperature rise rate, in the first time... t Within 1, the battery pack output power will be reduced from the first output power. P 1 is reduced to the second output power P 2;3) When the real-time discharge temperature exceeds the second discharge temperature threshold but does not exceed the third discharge temperature threshold, regardless of the magnitude of the first actual temperature rise rate, at the second time... t Within 2, the battery pack output power will be changed from the second output power. P 2 is reduced to the third output power P 3; 4) When the real-time discharge temperature exceeds the third discharge temperature threshold but does not exceed the fourth discharge temperature threshold, if the first actual temperature rise rate is less than the first temperature rise rate threshold, at the third time... t Within 3, the battery pack output power will be reduced from the third output power. P 3 is reduced to the fourth output power P 4; 5) When the real-time discharge temperature exceeds the third discharge temperature threshold but does not exceed the fourth discharge temperature threshold, if the first actual temperature rise rate exceeds the first temperature rise rate threshold, then at the fourth time... t 4. The battery pack output power will be reduced from the third output power. P 3 was reduced to the fifth highest output power. P 5; 6) If the actual temperature exceeds the fourth discharge temperature threshold, and after reducing the output power in cases 2), 3), 4), or 5) of the above-mentioned power reduction discharge strategy, the first actual temperature rise rate still exceeds the first temperature rise rate threshold and remains there for more than 10 seconds, or the interval between two consecutive power reductions does not exceed 30 seconds, then at the fifth time... t Within 5 days, the current output power will be reduced to 0. In the above strategy... t 1> t 2> t 3> t 4> t5; and the output power meets the requirements. P 1> P 2> P 3> P 4> P 5. The first actual temperature rise rate is essentially the rate of temperature change between adjacent sampling periods, such as the temperature change at the relay contact copper busbar position per second or per minute. When the output power drops to 0, it essentially activates the fuse to protect the electrical structure.

[0023] In this embodiment, the first discharge temperature threshold, the second discharge temperature threshold, the third discharge temperature threshold, and the fourth temperature threshold can be set to 90℃, 110℃, 120℃, and 130℃ respectively. Of course, they can also be a set of discrete temperature values ​​set manually.

[0024] As a preferred embodiment, the battery pack output power in this application... P 1. P 2. P 3. P 4 and P 5 is calculated based on the derating ratio, current discharge voltage, rated current, ambient temperature effect, aging effect, or voltage effect. The expression for the battery pack output power is as follows: ,in This is the reduction ratio coefficient. ; This is the current discharge voltage. Rated voltage, These are exponential parameters, all of which are real numbers greater than 1; Rated current; For the influence of ambient temperature, For ambient temperature, These are the temperature fitting coefficients. 25 is the reference ambient temperature; For the effects of aging, These are the fitting coefficients for the charging cycle and the cumulative mileage. To accumulate the number of charging cycles, This represents the cumulative driving mileage. It is evident that this embodiment, when implementing the power reduction strategy, fully considers factors related to battery aging, dynamic discharge voltage, and ambient temperature compensation related to cycle count and mileage, resulting in more precise power control that better matches load demands and avoids the risk of output overload.

[0025] In one embodiment, the parameter in the above scheme is the first time. t 1 is 30 seconds; the second time t 2 is 20 seconds; third time t 3 is 10 seconds; fourth time t 4 is 5 seconds; the fifth timet 5 represents 1 second. The first temperature rise rate threshold is 1℃ / s. Of course, the above time is based on the risk of high temperature overheating. As the current temperature increases, the corresponding time will be set shorter and shorter, eventually actively disconnecting the power output to avoid risks such as high-voltage system fires and high-voltage short circuits leading to loss of control.

[0026] S3: During charging, the fast charging relay and main negative relay of the BDU close to charge the battery pack. The temperature sensor obtains the third real-time temperature of the contact copper busbars of the fast charging relay and main negative relay. T 3 and 4 real-time temperatures T 4. Combined with the third real-time temperature T 3 or 4 real-time temperature T The second actual temperature rise rate of 4 is compared with several charging temperature thresholds and the second temperature rise rate threshold, and the BMS terminal executes a current reduction charging strategy during the charging process.

[0027] Specifically, several charging temperature thresholds are set, with the first, second, third, and fourth charging temperature thresholds increasing sequentially, and the third real-time temperature threshold being the lowest value. T 3 or 4 real-time temperature T The larger of 4 is the real-time charging temperature. Combined with the second actual temperature rise rate, the following current-reducing charging strategy is set for the charging process: 1) When the real-time charging temperature does not exceed the first charging temperature threshold, regardless of the magnitude of the second actual temperature rise rate, the rated current is applied. 1) Charging; 2) When the real-time charging temperature exceeds the first charging temperature threshold but does not exceed the second charging temperature threshold, regardless of the magnitude of the second actual temperature rise rate, at the sixth time... t Within 6 hours, the current charging current will be linearly reduced from the rated current to the first charging current. I 1;3) When the real-time charging temperature exceeds the second charging temperature threshold but does not exceed the third charging temperature threshold, regardless of the magnitude of the second actual temperature rise rate, at the seventh time... t Within 7 days, the current charging current will be changed from the first charging current. I 1. Adjust to the second charging current I 2;4) When the actual charging temperature exceeds the third charging temperature threshold but does not exceed the fourth temperature threshold, if the second actual temperature rise rate is less than the second temperature rise rate threshold, then at the eighth time... t Within 8 days, the current charging current will be changed from the second charging current. I 2. Adjust to the third charging current I 3;5) When the actual charging temperature exceeds the third charging temperature threshold but does not exceed the fourth temperature threshold, if the second actual temperature rise rate exceeds the second temperature rise rate threshold, then at the ninth time... t Within 9 minutes, the current charging current will be changed from the second charging current. I2. Adjust to the fourth charging current I 4; 6) If the actual charging temperature exceeds the fourth temperature threshold, and after reducing the charging current in cases 2), 3), 4), or 5) of the above-mentioned current reduction charging strategy, the second actual temperature rise rate still exceeds the second temperature rise rate threshold and remains there for more than 10 seconds, or the interval between two consecutive stages of reducing the charging current does not exceed 30 seconds, then at the tenth time... t Within 10 minutes, the current charging current will be reduced to 0; among which... t 6> t 7> t 8> t 9> t 10; When the charging current drops to 0, it essentially activates the fuse, protecting the circuit from further heat buildup.

[0028] In one embodiment, the first charging current I 1 is obtained by linearly decreasing the rated current; the second charging current. I 2 refers to the first charging current I The third charging current was obtained by a linear decreasing method. I 3 refers to the second charging current I The fourth charging current was obtained by a linear decreasing method. I 4 refers to the third charging current I 3. Obtained by linear descent: I 1 = 0.8 × I rated , I 2 = 0.8 × I 1, I 3 = 0.8 × I 2, I 4 = 0.5 × I 3. The Sixth Time t 6 is 10 seconds; the seventh time t 7 is 10 seconds; the eighth time t 8 is 10 seconds; the ninth time t 9 is 5 seconds; the tenth time t 10 seconds equals 1 second. This step-by-step linear decrease in charging current avoids the rapid accumulation of heat caused by high current during charging, ensuring safety without significantly reducing charging efficiency. The charging current will only decrease in a continuous gradient unless the temperature of the relay contacts rises too quickly. Even if the instantaneous temperature is too high or the second actual temperature rise rate is too high, about 10 seconds of fuse trigger judgment time is provided to avoid interference from instantaneous noise jumps.

[0029] In another embodiment, a second temperature rise rate threshold of 1°C / s is given. Of course, the second temperature rise rate threshold can be the same as or different from the first temperature rise rate threshold.

[0030] On the other hand, the present invention also provides a high-voltage electrical box temperature control system for implementing the above-mentioned method, characterized in that it includes: BDU is used for electrical connection to a battery pack, motor, or charging device; The relay unit further includes a fast-charging relay, a main positive relay, and a main negative relay disposed within the BDU, with temperature sensors arranged at the contact point copper busbars of each relay. The BMS is electrically connected to the relay unit and the temperature sensor respectively; during the discharge process, the BDU selectively executes a power reduction discharge strategy based on the temperature of the contact copper busbars of the main positive relay and the main negative relay and the current value of the first actual temperature rise rate; or during the charging process, it obtains the temperature of the contact copper busbars of the fast charging relay and the main negative relay and the current value of the second actual temperature rise rate, and selectively executes a current reduction charging strategy.

[0031] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for temperature control of a high-voltage electrical box, characterized in that, Includes the following steps: S1: Temperature sensors are installed at the copper busbars of the fast charging relay, main positive relay and main negative relay contacts of the BDU. The temperature sensors send real-time temperature information to the BMS terminal through the wiring harness; the high voltage circuit of the BDU is electrically connected to the battery pack. S2: During the discharge process, the main positive relay and the main negative relay of the BDU close, providing power to the motor. The temperature sensor obtains the first real-time temperature of the contact copper busbars of the main positive relay and the main negative relay. T 1 and second real-time temperature T 2. Combined with the first real-time temperature T 1 or second real-time temperature T The first actual temperature rise rate of 2 is compared with several discharge temperature thresholds and the first temperature rise rate threshold, and the BMS terminal executes a power reduction discharge strategy for the discharge process.

2. The high-voltage electrical box temperature control method according to claim 1, characterized in that, Step S2 involves setting several discharge temperature thresholds, with the first, second, third, and fourth discharge temperature thresholds increasing sequentially; the first real-time temperature... T 1 or second real-time temperature T The larger of 2 is the real-time discharge temperature. Combined with the first actual temperature rise rate, the following power reduction discharge strategy is set for the discharge process: 1) When the real-time discharge temperature does not exceed the first discharge temperature threshold, regardless of the magnitude of the first actual temperature rise rate, the output power of the battery pack is the first output power. P 1; 2) When the real-time discharge temperature exceeds the first discharge temperature threshold but does not exceed the second discharge temperature threshold, regardless of the magnitude of the first actual temperature rise rate, in the first time... t Within 1, the battery pack output power will be reduced from the first output power. P 1 is reduced to the second output power P 2;3) When the real-time discharge temperature exceeds the second discharge temperature threshold but does not exceed the third discharge temperature threshold, regardless of the magnitude of the first actual temperature rise rate, at the second time... t Within 2, the battery pack output power will be changed from the second output power. P 2 is reduced to the third output power P 3; 4) When the real-time discharge temperature exceeds the third discharge temperature threshold but does not exceed the fourth discharge temperature threshold, if the first actual temperature rise rate is less than the first temperature rise rate threshold, at the third time... t Within 3, the battery pack output power will be reduced from the third output power. P 3 is reduced to the fourth output power P 4; 5) If the real-time discharge temperature exceeds the third discharge temperature threshold but does not exceed the fourth discharge temperature threshold, and if the first actual temperature rise rate exceeds the first temperature rise rate threshold, then at the fourth time... t 4. The battery pack output power will be reduced from the third output power. P 3 was reduced to the fifth highest output power. P 5; 6) If the actual temperature exceeds the fourth discharge temperature threshold, and after reducing the output power in cases 2), 3), 4), or 5) of the above-mentioned power reduction discharge strategy, the first actual temperature rise rate still exceeds the first temperature rise rate threshold and remains there for more than 10 seconds, or the interval between two consecutive power reductions does not exceed 30 seconds, then at the fifth time... t Within 5 days, the current output power will be reduced to 0. In the above strategy... t 1> t 2> t 3> t 4> t 5; and the output power meets the requirements. P 1> P 2> P 3> P 4> P 5.

3. The high-voltage electrical box temperature control method according to claim 2, characterized in that, The output power of the battery pack is calculated based on the derating ratio, current discharge voltage, rated current, ambient temperature effect, aging effect, or voltage effect.

4. The high-voltage electrical box temperature control method according to claim 2, characterized in that, First time t 1 is 30 seconds; the second time t 2 is 20 seconds; third time t 3 is 10 seconds; fourth time t 4 is 5 seconds; the fifth time t 5 represents 1 second.

5. The high-voltage electrical box temperature control method according to claim 2, characterized in that, The first temperature rise rate threshold is 1℃ / s.

6. The high-voltage electrical box temperature control method according to claim 3, characterized in that, It also includes step S3, which involves setting several charging temperature thresholds, with the first, second, third, and fourth charging temperature thresholds increasing sequentially, and the third real-time temperature... T 3 or 4 real-time temperature T The larger of 4 is the real-time charging temperature. Combined with the second actual temperature rise rate, the following current-reducing charging strategy is set for the charging process: 1) When the real-time charging temperature does not exceed the first charging temperature threshold, regardless of the magnitude of the second actual temperature rise rate, the rated current is applied. 1) Charging; 2) When the real-time charging temperature exceeds the first charging temperature threshold but does not exceed the second charging temperature threshold, regardless of the magnitude of the second actual temperature rise rate, at the sixth time... t Within 6 hours, the current charging current will be linearly reduced from the rated current to the first charging current. I 1;3) When the real-time charging temperature exceeds the second charging temperature threshold but does not exceed the third charging temperature threshold, regardless of the magnitude of the second actual temperature rise rate, at the seventh time... t Within 7 days, the current charging current will be changed from the first charging current. I 1. Adjust to the second charging current I 2;4) When the actual charging temperature exceeds the third charging temperature threshold but does not exceed the fourth temperature threshold, if the second actual temperature rise rate is less than the second temperature rise rate threshold, then at the eighth time... t Within 8 days, the current charging current will be changed from the second charging current. I 2. Adjust to the third charging current I 3; 5) If the actual charging temperature exceeds the third charging temperature threshold but does not exceed the fourth temperature threshold, and if the second actual temperature rise rate exceeds the second temperature rise rate threshold, then at the ninth time... t Within 9 minutes, the current charging current will be changed from the second charging current. I 2. Adjust to the fourth charging current I 4; 6) If the actual charging temperature exceeds the fourth temperature threshold, and after reducing the charging current in cases 2), 3), 4), or 5) of the above-mentioned current reduction charging strategy, the second actual temperature rise rate still exceeds the second temperature rise rate threshold and remains there for more than 10 seconds, or the interval between two consecutive stages of reducing the charging current does not exceed 30 seconds, then at the tenth time... t Within 10 minutes, the current charging current will be reduced to 0; among which... t 6> t 7> t 8> t 9> t 10; .

7. The high-voltage electrical box temperature control method according to claim 6, characterized in that, The first charging current I 1 is obtained by the linear decrease of the rated current; Second charging current I 2 refers to the first charging current I It was obtained through a linear descent method; Third charging current I 3 refers to the second charging current I The fourth charging current was obtained by a linear decreasing method. I 4 refers to the third charging current I 3. Obtained by linear descent: I 1 = 0.8 × I rated , I 2 = 0.8 × I 1, I 3 = 0.8 × I 2, I 4 = 0.5 × I 3.

8. The high-voltage electrical box temperature control method according to claim 6, characterized in that, The sixth time t 6 is 10 seconds; the seventh time t 7 is 10 seconds; the eighth time t 8 is 10 seconds; the ninth time t 9 is 5 seconds; the tenth time t 10 equals 1 second.

9. A method for temperature control of a high-voltage electrical box according to claim 6, characterized in that, The second temperature rise rate threshold is 1℃ / s.

10. A high-voltage electrical box temperature control system, used to implement the method according to any one of claims 1-9, characterized in that, include: BDU is used for electrical connection to a battery pack, motor, or charging device; The relay unit further includes a fast-charging relay, a main positive relay, and a main negative relay disposed within the BDU, with temperature sensors arranged at the contact point copper busbars of each relay. The BMS is electrically connected to the relay unit and the temperature sensor respectively; during the discharge process, the BDU selectively executes a power reduction discharge strategy based on the temperature of the contact copper busbars of the main positive relay and the main negative relay, and the current value of the first actual temperature rise rate. Alternatively, during the charging process, the temperature of the contact copper busbars of the fast charging relay and the main negative relay, as well as the current value of the second actual temperature rise rate, can be obtained to selectively execute a reduced current charging strategy.

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