Power battery system temperature control method

Abstract

The present invention relates to a method for controlling the temperature of a power battery system, comprising the steps of: obtaining a vehicle's motion state and temperature control state; if the vehicle is in a driving state and a cooling state, executing a driving cooling control sub-process; if the vehicle is in a charging state and a cooling state, executing a charging cooling control sub-process; if the vehicle is in a driving state and a heating state, executing a driving heating control sub-process; if the vehicle is in a charging state and a heating state, executing a charging heating control sub-process; if the vehicle is in a driving state and a temperature-averaging self-circulation state, executing a driving temperature-averaging self-circulation control sub-process; if the vehicle is in a charging state and a temperature-averaging self-circulation state, executing a charging temperature-averaging self-circulation control sub-process. The present invention only takes into account the power battery system's own state indicators, and under the premise of ensuring that the operating temperature of the power battery system meets the battery safety and life requirements, effectively reduces battery energy consumption; reduces the maximum temperature difference of the battery cells caused by long-term uneven heat release or uneven cooling; and alleviates battery life loss.

Description

Technical Field

[0001] The present invention relates to the technical field of electric vehicles, and in particular to a temperature control method for a power battery system. Background Art

[0002] Current electric vehicles typically use rechargeable lithium-ion batteries as the energy storage element in their power battery systems. To ensure the safety and service life of lithium-ion batteries, the charging and discharging of power battery systems must be strictly controlled within an appropriate temperature range. Charging and discharging outside the allowable operating temperature range may cause the battery to short-circuit and cause thermal runaway, which is a serious risk. At the very least, the battery's service life may be significantly shortened compared to normal temperature operation.

[0003] To address the above issues, existing electric vehicle battery systems typically have a matching thermal management system for temperature regulation. To minimize energy loss caused by the thermal management system while maintaining the battery temperature within an appropriate range, the following patent applications are typical examples of existing technical solutions:

[0004] A typical example is the Chinese patent application number CN202210216299.9, entitled "Power Battery Charging Thermal Management Method, Device, Electronic Device, and Storage Medium," which discloses a power battery charging thermal management method, device, electronic device, and storage medium, including: obtaining a first state parameter of the power battery, where the first state parameter includes at least a first temperature parameter and a first voltage parameter; determining a first preset charging capacity of the power battery based on the first state parameter; and controlling the on / off state of the thermal management system based on the first preset charging capacity of the power battery and the output charging capacity of the charging device. This solution aims to adjust the thermal management system in real time based on parameters such as the first preset charging capacity of the power battery and the output charging capacity of the charging device, thereby shortening the charging time of the power battery and reducing unnecessary charging energy consumption during the charging process.

[0005] Another typical example is Chinese patent application number CN202311238689.7, entitled "Pure Electric Vehicle Power Battery Thermal Management Control Method, System, and Vehicle," which discloses a pure electric vehicle power battery thermal management control method, system, and vehicle. The method includes obtaining vehicle travel road condition information, determining the vehicle's steady-state drive power and instantaneous drive power based on the travel road condition information, collecting the current power battery state of charge (SOC) and second state parameter information, determining the battery's heating temperature data value and estimated temperature rise duration value, and obtaining a corrected heating target temperature value and a corrected estimated temperature rise duration value based on the ratio of the estimated temperature rise duration value to the travel duration data value. Based on the current battery temperature data value, the corrected heating target temperature value, and the corrected estimated temperature rise duration value, a secondary correction is performed to obtain an executed temperature rise duration value and execute a thermal management control strategy. This solution is expected to achieve the goal of optimal vehicle driving economy while meeting future travel power requirements by taking into account the relationship between travel duration and actual thermal management time.

[0006] Another typical example is the Chinese patent application with application number CN202311824676.8, entitled "Heating Control Method, Device, Vehicle, and Electronic Equipment for Vehicle Power Battery," which provides a heating control method, device, vehicle, electronic equipment, and storage medium for a vehicle power battery. The method includes: obtaining power consumption data required for the vehicle to travel a preset mileage; obtaining state-of-charge interval data corresponding to the power consumption data; obtaining a target heating temperature based on the state-of-charge interval data; obtaining an expected heating time based on the target heating temperature; and controlling the heating of the power battery based on the expected heating time to obtain a heating control result. This technical solution is expected to improve the efficiency of power battery heating control, more reasonably control the temperature of the power battery, and save energy consumption.

[0007] Another typical example is Chinese patent application number CN202410216508.9, titled "Vehicle Power Battery Thermal Management Method, Storage Medium, Electronic Device, and Vehicle." This patent discloses a vehicle power battery thermal management method, storage medium, electronic device, and vehicle, including: obtaining the vehicle's current driving data and determining a target driving range and target driving style based on the current driving data; determining a cooling activation temperature threshold based on the target driving range and target driving style; and cooling the power battery when the battery temperature of the vehicle power battery is greater than the cooling activation temperature threshold. This method is expected to reduce energy consumption for thermal management during vehicle operation.

[0008] The defects of the prior art are:

[0009] 1. If thermal management is not considered when using a power battery system, energy conservation may be wasted due to unnecessary cooling and heating of the battery during parking and charging, or during driving. This not only shortens the driving range in hot or cold weather, but also leads to unnecessary increases in the user's electricity costs.

[0010] 2. Since the aforementioned patented technical solutions only consider one of the two typical basic operating conditions of parking charging or driving electricity consumption, or the technical judgment conditions adopted are too complex or too simple in actual application, they cannot actually effectively match the actual application status of the power battery.

[0011] To sum up, existing technologies are actually unable to solve current technical problems and have no possibility of practical application. They only have theoretical possibilities, and some of them are not even valid as technical solutions. Summary of the Invention

[0012] In response to the above-mentioned problems, the present invention provides a power battery system temperature control method, which aims to effectively reduce battery energy consumption while ensuring that the operating temperature of the power battery system meets the battery safety and life requirements, based only on the power battery system's own status indicators such as battery charging or discharging current rate, battery SOC status, and battery temperature; reduce the maximum temperature difference of the battery cells caused by long-term uneven heat release or uneven cooling; and alleviate battery life loss.

[0013] In order to solve the above problems, the technical solution provided by the present invention is:

[0014] A method for controlling the temperature of a power battery system comprises the following steps:

[0015] S100 obtains the current vehicle motion state, temperature control state; the vehicle motion state includes driving state, charging state; the temperature control state includes cooling state, heating state, and temperature self-circulation state;

[0016] S200. Perform the following operations based on the vehicle motion state and the temperature control state:

[0017] If the vehicle motion state is the driving state, and the temperature control state is the cooling state, executing S300;

[0018] If the vehicle motion state is the charging state and the temperature control state is the cooling state, executing S400;

[0019] If the vehicle motion state is the driving state, and the temperature control state is the heating state, executing S500;

[0020] If the vehicle motion state is the charging state, and the temperature control state is the heating state, executing S600;

[0021] If the vehicle motion state is the driving state, and the temperature control state is the temperature-averaging self-circulating state, then execute S700;

[0022] If the vehicle motion state is the charging state, and the temperature control state is the temperature-averaging self-circulation state, execute S800;

[0023] S300. Execute the driving cooling control sub-process;

[0024] S400. Execute the charging cooling control sub-process;

[0025] S500. Execute the driving heating control sub-process;

[0026] S600. Execute charging and heating control sub-process;

[0027] S700. Execute the driving temperature self-circulation control sub-process;

[0028] S800. Execute the charging temperature equalization self-circulation control sub-process.

[0029] Preferably, the driving cooling control sub-process in S300 specifically includes the following steps:

[0030] S310. Real-time collection of the discharge current rate, SOC, cell temperature of each cell in the battery pack, and the average temperature of the battery pack; then timestamping the collected discharge current rate, SOC, cell temperature, and average temperature of the battery pack according to the time of collection, and arranging them in increasing order of the timestamps;

[0031] S320. For each discharge current rate, calculate the arithmetic mean within the 10-minute range before the corresponding timestamp to obtain the average discharge current rate corresponding to the timestamp; if the time between the corresponding timestamp and the starting time point is less than 10 minutes, calculate the average discharge current rate between the corresponding timestamp and the starting time point; then stamp the calculated average discharge current rate with the corresponding timestamp and arrange them in ascending order of the timestamps;

[0032] S330. Check the temperature of the single cell and the average temperature of the battery pack corresponding to each timestamp in real time; then perform the following operations based on the check results:

[0033] If there is a timestamp corresponding to which the highest temperature of the single battery cell is not lower than a manually preset first temperature threshold, and the average temperature of the battery pack corresponding to the timestamp is not lower than a manually preset second temperature threshold, then execute S340;

[0034] If there is a timestamp corresponding to which the highest temperature of the single battery cell is not lower than the second temperature threshold, and the average temperature of the battery pack corresponding to the timestamp is not lower than the manually preset third temperature threshold, then execute S350;

[0035] Otherwise, return and execute S310 again;

[0036] S340. Check the average discharge current rate and the SOC corresponding to the timestamp in S330; then perform the following operations based on the check result:

[0037] If the average discharge current rate corresponding to the timestamp in S330 is between the manually preset first current rate and the second current rate, and the SOC is not less than 20%, then the first driving cooling control sub-process is executed;

[0038] Otherwise, return and execute S310 again;

[0039] S350. Check the average discharge current rate and the SOC corresponding to the timestamp in S330; then perform the following operations based on the check result:

[0040] If the average discharge current rate corresponding to the timestamp in S330 is not lower than the first current rate, and the SOC is not lower than 20%, then executing the second driving cooling control sub-process;

[0041] Otherwise, return and execute S310 again;

[0042] The first driving cooling control sub-process specifically includes the following contents:

[0043] Sa341. Set the SOC management strategy effective range to 20% to 100%;

[0044] Sa342. Set the current rate management strategy effective range to 0.15C ~ 0.30C;

[0045] Sa343. The target water temperature of the water-cooled unit coolant is set to the manually preset twentieth temperature threshold;

[0046] Sa344. Check the single cell temperature, the average temperature of the battery pack, the average discharge current rate, and the SOC corresponding to the current timestamp; then perform the following operations based on the check results:

[0047] If there is a timestamp corresponding to which the average discharge current rate is less than the second current rate, or the corresponding SOC is lower than 20%, or the corresponding maximum temperature of the single battery is not higher than the second temperature threshold, or the corresponding average temperature of the battery pack is not higher than the third temperature threshold, then the first driving cooling control sub-process is closed;

[0048] Otherwise, return and execute Sa344 again;

[0049] The second driving cooling control sub-process specifically includes the following contents:

[0050] Sa351. Set the SOC management strategy effective range to 20% to 100%;

[0051] Sa352. Set the current rate management strategy effective range to 0.30C to 0.80C and above 0.80C;

[0052] Sa353. The target water temperature of the water-cooled unit coolant is set to the manually preset 21st temperature threshold;

[0053] Sa353. Check the single cell temperature, the average temperature of the battery pack, the average discharge current rate, and the SOC corresponding to the current timestamp; then perform the following operations based on the check results:

[0054] If there is a timestamp corresponding to which the average discharge current rate is less than the second current rate, or the corresponding SOC is lower than 20%, or the corresponding maximum temperature of the single battery is not higher than the third temperature threshold, or the corresponding average temperature of the battery pack is not higher than the manually preset fourth temperature threshold, then the second driving cooling control sub-process is closed;

[0055] Otherwise, return and execute Sa351 again.

[0056] Preferably, the charging cooling control sub-process in S400 specifically includes the following steps:

[0057] S410. Collecting the charging current rate, SOC, the temperature of each battery cell in the battery pack, and the average temperature of the battery pack in real time; then timestamping the collected charging current rate, SOC, the temperature of each battery cell, and the average temperature of the battery pack according to the time of collection, and arranging them in increasing order of the timestamps;

[0058] S420. Check the temperature of the single battery cell and the average temperature of the battery pack corresponding to each timestamp in real time; then perform the following operations based on the check results:

[0059] If there is a timestamp corresponding to which the highest temperature of the single battery cell is not lower than the third temperature threshold, and the average temperature of the battery pack corresponding to the timestamp is not lower than the manually preset seventh temperature threshold, then execute S430;

[0060] If there is a timestamp corresponding to which the highest temperature of the single battery cell is not lower than the second temperature threshold, and the average temperature of the battery pack corresponding to the timestamp is not lower than the third temperature threshold, executing S440;

[0061] If there is a timestamp corresponding to which the highest temperature of the single battery cell is not lower than the first temperature threshold, and the average temperature of the battery pack corresponding to the timestamp is not lower than the second temperature threshold, executing S450;

[0062] Otherwise, return and execute S410 again;

[0063] S430. Check the charging current rate and the SOC corresponding to the timestamp in S420; then perform the following operations based on the check result:

[0064] If the charging current rate corresponding to the timestamp in S420 is higher than a manually preset fourth current rate, and the SOC is not higher than 30%, executing the first charging and cooling control sub-process;

[0065] Otherwise, return and execute S410 again;

[0066] S440. Check the charging current rate and the SOC corresponding to the timestamp in S420; then perform the following operations based on the check result:

[0067] If the charging current rate corresponding to the timestamp in S420 is between the third current rate and the fourth current rate, and the SOC is between 30% and 80%, then executing the second driving cooling control sub-process;

[0068] Otherwise, return and execute S410 again;

[0069] S450. Check the charging current rate and the SOC corresponding to the timestamp in S420; then perform the following operations based on the check result:

[0070] If the charging current rate corresponding to the timestamp in S420 is less than the third current rate, and the SOC is between 80% and 100%, executing the third driving cooling control sub-process;

[0071] Otherwise, return and execute S410 again;

[0072] The first charging and cooling control sub-process specifically includes the following steps:

[0073] Sa431. Set the SOC management strategy effective range to 0% to 30%;

[0074] Sa432. Set the current rate management strategy effective range to 0.80C and above;

[0075] Sa433. The target water temperature of the water-cooling unit coolant is set to the 21st temperature threshold;

[0076] Sa434. Check the single cell temperature and the battery pack temperature corresponding to the current timestamp; then perform the following operations based on the check results:

[0077] If there is a timestamp corresponding to which the highest temperature of the single battery cell is not higher than the manually preset fourth temperature threshold, or the corresponding battery pack temperature is not higher than the manually preset eighth temperature threshold, then closing the first driving cooling control sub-process;

[0078] Otherwise, return and execute Sa434 again;

[0079] The second charging and cooling control sub-process specifically includes the following steps:

[0080] Sa441. Set the SOC management strategy effective range to 30% to 80%;

[0081] Sa442. Set the current rate management strategy effective range to 0.50C ~ 0.80C;

[0082] Sa443. Set the target water temperature of the water-cooling unit coolant to the twenty-first temperature threshold;

[0083] Sa444. Check the single cell temperature and the battery pack temperature corresponding to the current timestamp; then perform the following operations based on the check results:

[0084] If the highest temperature of the single battery cell corresponding to a timestamp is not higher than the manually preset sixth temperature threshold, or the corresponding battery pack temperature is not higher than the fourth temperature threshold, then closing the second driving cooling control sub-process;

[0085] Otherwise, return and execute Sa444 again;

[0086] The third charging and cooling control sub-process specifically includes the following steps:

[0087] Sa451. Set the SOC management policy effective range to 80% to 100%;

[0088] Sa452. Set the current rate management strategy effective range to 0.10C to 0.50C;

[0089] Sa453. The target water temperature of the water-cooled unit coolant is set to the manually preset twentieth temperature threshold;

[0090] Sa454. Check the single cell temperature and the battery pack temperature corresponding to the current timestamp; then perform the following operations based on the check results:

[0091] If the highest temperature of the single battery cell corresponding to a timestamp is not higher than the manually preset fifth temperature threshold, or the corresponding battery pack temperature is not higher than the sixth temperature threshold, then the third driving cooling control sub-process is closed;

[0092] Otherwise, return and execute Sa454 again.

[0093] Preferably, the vehicle heating control sub-process in S500 specifically includes the following steps:

[0094] S510. Collecting in real time the discharge current rate, SOC, the temperature of each battery cell in the battery pack, and the average temperature of the battery pack; then timestamping the collected discharge current rate, SOC, battery cell temperature, and average temperature of the battery pack according to the time of collection, and arranging them in increasing order of the timestamps;

[0095] S520. Check the temperature of the single battery cell and the average temperature of the battery pack corresponding to each timestamp in real time; then perform the following operations based on the check results:

[0096] If there is a timestamp corresponding to which the lowest temperature of the single battery cell is not higher than the manually preset tenth temperature threshold, and the average temperature of the battery pack corresponding to this timestamp is not higher than the manually preset ninth temperature threshold, then execute S530;

[0097] S530. Check the SOC corresponding to the timestamp in S520; then, based on the check result, perform the following operations:

[0098] If the SOC corresponding to the timestamp in S520 is not less than 30%, executing the driving heating control sub-process;

[0099] Otherwise, return and execute S510 again;

[0100] The vehicle heating control sub-process specifically includes the following steps:

[0101] S511. Set the SOC management policy effective range to 30% to 100%;

[0102] S512. Set the current rate management strategy effective range to 0.15C to 0.80C and above;

[0103] S513. The target water temperature of the water-cooling unit coolant is set to the manually preset 23rd temperature threshold;

[0104] S514. For each discharge current rate, calculate the arithmetic mean within the 60 minutes before the corresponding timestamp to obtain the average discharge current rate corresponding to the timestamp; if the time between the corresponding timestamp and the starting time point is less than 60 minutes, calculate the average discharge current rate between the corresponding timestamp and the starting time point; then stamp the calculated average discharge current rate with the corresponding timestamp and arrange them in ascending order of the timestamps;

[0105] S515. Check the single cell temperature, the average temperature of the battery pack, the average discharge current rate, and the SOC corresponding to the current timestamp; then perform the following operations based on the check results:

[0106] If there is a timestamp corresponding to which the average discharge current rate is less than the second current rate, or the corresponding SOC is lower than 30%, or the corresponding lowest temperature of the single battery is not lower than the ninth temperature threshold, or the corresponding average temperature of the battery pack is not lower than the manually preset eleventh temperature threshold, then the driving heating control sub-process is closed;

[0107] Otherwise, return and execute S510 again.

[0108] Preferably, the charging heating control sub-process in S600 specifically includes the following steps:

[0109] S610. Real-time collection of charging current rate, SOC, cell temperature of each cell in the battery pack, and average temperature of the battery pack provided by the charging pile; then the collected charging current rate, SOC, cell temperature, and average temperature of the battery pack provided by the charging pile are timestamped at the time of collection and arranged in ascending order of the timestamps;

[0110] S620. Check the temperature of the single cell and the average temperature of the battery pack corresponding to each timestamp in real time; then perform the following operations based on the check results:

[0111] If there is a timestamp corresponding to which the lowest temperature of the single battery cell is not higher than the manually preset thirteenth temperature threshold, and the average temperature of the battery pack corresponding to the timestamp is not higher than the manually preset twelfth temperature threshold, execute S630;

[0112] If there is a timestamp corresponding to which the lowest temperature of the single battery cell is not higher than the manually preset fourteenth temperature threshold, and the battery pack average temperature corresponding to the timestamp is not higher than the manually preset seventeenth temperature threshold, execute S640;

[0113] If there is a timestamp corresponding to which the lowest temperature of the single battery cell is not higher than the manually preset fifteenth temperature threshold, and the average temperature of the battery pack corresponding to this timestamp is not higher than the manually preset eighteenth temperature threshold, then execute S650;

[0114] Otherwise, return and execute S610 again;

[0115] S630. Check whether the charging pile corresponding to the timestamp in S620 can provide the charging current rate and the SOC; then, based on the check result, perform the following operations:

[0116] If the charging pile corresponding to the timestamp in S620 can provide a charging current rate higher than the fourth current rate, and the SOC is not higher than 30%, then executing the first charging and heating control sub-process;

[0117] Otherwise, return and execute S610 again;

[0118] S640. Check whether the charging pile corresponding to the timestamp in S620 can provide the charging current rate and the SOC; then perform the following operations based on the check result:

[0119] If the charging pile corresponding to the timestamp in S620 can provide a charging current rate between the third current rate and the fourth current rate, and the SOC is between 30% and 80%, then execute the second charging and heating control sub-process;

[0120] Otherwise, return and execute S610 again;

[0121] S650. Check whether the charging pile corresponding to the timestamp in S620 can provide the charging current rate and the SOC; then perform the following operations based on the check result:

[0122] If the charging current rate provided by the charging pile corresponding to the timestamp in S620 is less than the third current rate, and the SOC is between 80% and 100%, then executing the third charging and heating control sub-process;

[0123] Otherwise, return and execute S610 again;

[0124] The first charging and heating control sub-process specifically includes the following steps:

[0125] Sa631. Set the SOC management strategy effective range to 0% to 30%;

[0126] Sa632. Set the current rate management strategy effective range to the charging current rate that the charging pile can provide;

[0127] Sa633. The target water temperature of the water-cooled unit coolant is set to the manually preset 22nd temperature threshold;

[0128] Sa634. Check the single cell temperature and the battery pack temperature corresponding to the current timestamp; then perform the following operations based on the check results:

[0129] If there is a timestamp corresponding to which the lowest temperature of the single battery cell is not lower than the manually preset twelfth temperature threshold, and the corresponding battery pack temperature is not lower than the manually preset sixteenth temperature threshold, then closing the first charging and heating control sub-process;

[0130] Otherwise, return and execute Sa634 again;

[0131] The second charging and heating control sub-process specifically includes the following steps:

[0132] Sa641. Set the SOC management policy effective range to 30% to 80%;

[0133] Sa642. Set the current rate management strategy effective range to the charging current rate that the charging pile can provide;

[0134] Sa643. Set the target water temperature of the water-cooling unit coolant to the twenty-second temperature threshold;

[0135] Sa644. Check the single cell temperature and the battery pack temperature corresponding to the current timestamp; then perform the following operations based on the check results:

[0136] If there is a timestamp corresponding to which the lowest temperature of the single battery cell is not lower than a manually preset thirteenth temperature threshold, and the corresponding battery pack temperature is not lower than a manually preset twelfth temperature threshold, then closing the second charging and heating control sub-process;

[0137] Otherwise, return and execute Sa644 again;

[0138] The third charging and heating control sub-process specifically includes the following steps:

[0139] Sa651. Set the SOC management policy effective range to 80% to 100%;

[0140] Sa652. Set the current rate management strategy effective range to the charging current rate that the charging pile can provide;

[0141] Sa653. Set the target water temperature of the water-cooling unit coolant to the twenty-second temperature threshold;

[0142] Sa654. Check the single cell temperature and the battery pack temperature corresponding to the current timestamp; then perform the following operations based on the check results:

[0143] If there is a time stamp corresponding to which the lowest temperature of the single battery cell is not lower than the manually preset fourteenth temperature threshold, or the corresponding battery pack temperature is not lower than the manually preset seventeenth temperature threshold, then the third charging and heating control sub-process is closed;

[0144] Otherwise, return and execute Sa654 again.

[0145] Preferably, the driving temperature averaging self-circulation control sub-process in S700 specifically includes the following steps:

[0146] S710. Collecting the charging current rate, SOC, the temperature of each battery cell in the battery pack, and the average temperature of the battery pack in real time; then timestamping the collected charging current rate, SOC, the temperature of each battery cell, and the average temperature of the battery pack according to the time of collection, and arranging them in increasing order of the timestamps;

[0147] S720. Check whether cooling and heating are currently on; then make the following operations based on the check results.

[0148] If cooling is not currently on and heating is not on, execute S730;

[0149] If cooling is currently on, or heating is on, return to and execute S720 again;

[0150] S730. Check the SOC, the single cell temperature, and the average temperature of the battery pack corresponding to each of the timestamps in real time; then perform the following operations based on the check results:

[0151] If there is a time stamp corresponding to the SOC of not less than 20%, and the difference between the highest temperature of the single battery cell and the lowest temperature of the single battery cell is not less than the manually preset 24th temperature threshold, then executing the driving temperature averaging self-circulation control sub-process;

[0152] Otherwise, return and execute S710 again;

[0153] The driving temperature average self-circulation control sub-process specifically includes the following steps:

[0154] Sa731. Set the SOC management policy effective range to 20% to 100%;

[0155] Sa732. Set the current rate management strategy effective range to 0.15C to 0.80C and above;

[0156] Sa733. Start water circulation;

[0157] Sa734. For each discharge current rate, calculate the arithmetic mean within the 60 minutes before the corresponding timestamp to obtain the average discharge current rate corresponding to the timestamp; if the time between the corresponding timestamp and the starting time point is less than 60 minutes, calculate the average discharge current rate between the corresponding timestamp and the starting time point; then stamp the calculated average discharge current rate with the corresponding timestamp and arrange them in ascending order of the timestamps;

[0158] Sa735. Check the single cell temperature, the average temperature of the battery pack, the average discharge current rate, and the SOC corresponding to the current timestamp; then perform the following operations based on the check results:

[0159] If the SOC corresponding to one of the timestamps is lower than 20%, or the difference between the corresponding maximum temperature of the single cell and the minimum temperature of the single cell is not higher than the 25th manually preset temperature threshold, or the average discharge current rate is lower than the second current rate, or the single cell temperature and the average temperature of the battery pack meet the manually preset cooling / heating judgment conditions, then the driving temperature averaging self-circulation control sub-process is closed;

[0160] Otherwise, return and execute Sa734 again.

[0161] Preferably, the charging temperature equalization self-circulation control sub-process in S800 specifically includes the following steps:

[0162] S810. Collecting the charging current rate, SOC, the temperature of each battery cell in the battery pack, and the average temperature of the battery pack in real time; then timestamping the collected charging current rate, SOC, the temperature of each battery cell, and the average temperature of the battery pack according to the time of collection, and arranging them in increasing order of the timestamps;

[0163] S820. Check whether cooling and heating are currently on; then make the following operations based on the check results.

[0164] If cooling is not currently on and heating is not on, execute S830;

[0165] If cooling is currently on, or heating is on, return to and execute S820 again;

[0166] S830. Check the SOC, the single cell temperature, and the average temperature of the battery pack corresponding to each of the timestamps in real time; then perform the following operations based on the check results:

[0167] If there is a time stamp corresponding to the SOC not higher than 80%,

[0168] and if the difference between the highest temperature of the single battery and the lowest temperature of the single battery is not lower than the twenty-fourth temperature threshold, then executing the charging temperature equalization self-circulation control sub-process;

[0169] Otherwise, return and execute S810 again;

[0170] The charging temperature equalization self-circulation control sub-process specifically includes the following steps:

[0171] Sa831. Set the SOC management strategy effective range to 0% to 80%;

[0172] Sa832. Start the water cycle;

[0173] Sa833. Check the single cell temperature, the average battery pack temperature, the average charging current rate, and the SOC corresponding to the current timestamp; then, perform the following operations based on the check results:

[0174] If the SOC corresponding to one of the timestamps is higher than 80%, or the difference between the corresponding highest temperature of the single cell and the lowest temperature of the single cell is not higher than the 25th temperature threshold, or the temperature of the single cell and the average temperature of the battery pack reach the manually preset cooling / heating judgment condition, then the current charging temperature equalization self-circulation control sub-process is closed;

[0175] Otherwise, return and execute Sa834 again.

[0176] Preferably, the first temperature threshold is 34°C; the second temperature threshold is 30°C; the third temperature threshold is 26°C; the fourth temperature threshold is 24°C; the fifth temperature threshold is 32°C; the sixth temperature threshold is 28°C; the seventh temperature threshold is 22°C; the eighth temperature threshold is 20°C; the ninth temperature threshold is 5°C; the tenth temperature threshold is 2°C; the eleventh temperature threshold is 8°C; the twelfth temperature threshold is 20°C; the thirteenth temperature threshold is 18°C; the fourteenth temperature threshold is 14°C; the fifteenth temperature threshold is 10°C; the sixteenth temperature threshold is 22°C; the seventeenth temperature threshold is 16°C; the eighteenth temperature threshold is 12°C; the twentieth temperature threshold is 20°C; the twenty-first temperature threshold is 15°C; the twenty-second temperature threshold is 45°C; the twenty-third temperature threshold is 40°C; the twenty-fourth temperature threshold is 8°C; and the twenty-fifth temperature threshold is 5°C.

[0177] Preferably, the first current magnification is 0.30C; the second current magnification is 0.15C; the third current magnification is 0.50C; and the fourth current magnification is 0.80C.

[0178] Preferably, in S200, if the vehicle motion state is the driving state, and if the thermal management unit does not normally respond to the cooling demand or heating demand of the BMS within 5 minutes after the cooling demand or heating demand is issued, the driving temperature averaging self-circulation control sub-process is executed;

[0179] In S200, if the vehicle movement state is the charging state, and if the thermal management unit does not normally respond to the cooling demand or heating demand of the BMS within 5 minutes after the cooling demand or heating demand is issued, the charging temperature equalization self-circulation control sub-process is executed.

[0180] Compared with the prior art, the present invention has the following advantages:

[0181] 1. The present invention effectively reduces battery energy consumption by adjusting the thermal management start / stop temperature threshold and target water temperature when the battery operates at lower power.

[0182] 2. Since the present invention also introduces a temperature-averaging self-circulation, it reduces the maximum temperature difference of the battery cells caused by long-term uneven heat release or uneven cooling, and further alleviates the loss of battery life. BRIEF DESCRIPTION OF THE DRAWINGS

[0183] Figure 1 Schematic diagram of the control method flow in a specific embodiment of the present invention. DETAILED DESCRIPTION

[0184] The present invention is further illustrated below with reference to specific examples. It should be understood that these examples are only used to illustrate the present invention and are not used to limit the scope of the present invention. After reading the present invention, modifications of various equivalent forms of the present invention made by those skilled in the art all fall within the scope defined by the claims attached to this application.

[0185] It should be noted that the power battery system involved in this specific embodiment is composed of the following components:

[0186] A power battery pack with a power distribution module and a battery management system, a charging port that matches the output port of an off-board conductive charger, and a thermal management unit that can provide cooling / heating functions according to battery needs.

[0187] Within the operating temperature range of the power battery system, the main ways of generating heat are Joule heat and polarization heat. The heat generation power Q is approximately I^2*(Rp+Re), where Rp is the ohmic internal resistance and Re is the polarization internal resistance. Under the same conditions, the battery temperature rise rate is mainly related to the current I, so setting different thermal management start-stop temperature thresholds requires first considering the average charge and discharge rate over a period of time; secondly, during the charging process, the discharge rate may be relatively large, but the amount of electricity to be charged may be low. Although the temperature rise rate is very high at this time, the total heat generation is not large. This requires setting the thermal management start-stop threshold in combination with the SOC when starting charging.

[0188] like Figure 1 As shown, a power battery system temperature control method includes the following steps:

[0189] S100. Obtain the current vehicle motion state and temperature control state; the vehicle motion state includes the driving state and the charging state; the temperature control state includes the cooling state, the heating state, and the temperature equalization self-circulation state.

[0190] S200. Perform the following operations based on the vehicle's motion status and temperature control status:

[0191] If the vehicle motion state is the driving state and the temperature control state is the cooling state, S300 is executed.

[0192] If the vehicle motion state is the charging state and the temperature control state is the cooling state, S400 is executed.

[0193] If the vehicle motion state is the driving state and the temperature control state is the heating state, S500 is executed.

[0194] If the vehicle motion state is the charging state and the temperature control state is the heating state, S600 is executed.

[0195] If the vehicle motion state is the driving state and the temperature control state is the temperature equalization self-circulation state, execute S700.

[0196] If the vehicle's motion state is the charging state, and the temperature control state is the temperature-averaging self-circulation state, execute S800.

[0197] In this specific embodiment, if the vehicle motion state is driving state in S200, and if the thermal management unit does not respond normally to the cooling demand or heating demand of the BMS within 5 minutes after the cooling demand or heating demand is issued, the driving temperature equalization self-circulation control sub-process is executed.

[0198] In this specific embodiment, if the vehicle's motion state is charging in S200, and if the thermal management unit does not respond normally to the BMS's cooling demand or heating demand within 5 minutes after issuing the cooling demand or heating demand, the charging temperature equalization self-circulation control sub-process is executed.

[0199] S300. Execute the driving cooling control sub-process.

[0200] In this specific embodiment, the vehicle cooling control sub-process in S300 specifically includes the following steps:

[0201] S310. Collect the discharge current rate, SOC, the temperature of each single cell in the battery pack, and the average temperature of the battery pack in real time; then timestamp the collected discharge current rate, SOC, single cell temperature, and average temperature of the battery pack according to the time of collection, and arrange them in increasing order of the timestamps.

[0202] S320. For each discharge current rate, calculate the arithmetic mean within the 10 minutes before the corresponding timestamp to obtain the average discharge current rate corresponding to this timestamp; if the time from the corresponding timestamp to the starting time point is less than 10 minutes, calculate the average discharge current rate between the corresponding timestamp and the starting time point; then mark the calculated average discharge current rate with the corresponding timestamp and arrange them in increasing order of timestamps.

[0203] S330. Check the single cell temperature and battery pack average temperature corresponding to each timestamp in real time; then, based on the check results, perform the following operations:

[0204] If there is a timestamp corresponding to a single battery whose highest temperature is not lower than a manually preset first temperature threshold, and the battery pack average temperature corresponding to this timestamp is not lower than a manually preset second temperature threshold, then S340 is executed.

[0205] If there is a timestamp corresponding to which the highest temperature of the single battery is not lower than the second temperature threshold, and the average temperature of the battery pack corresponding to this timestamp is not lower than the manually preset third temperature threshold, then S350 is executed.

[0206] Otherwise, return and execute S310 again.

[0207] S340. Check the average discharge current rate and SOC corresponding to the timestamp in S330; then, based on the check result, perform the following operations:

[0208] If the average discharge current rate corresponding to the timestamp in S330 is between the manually preset first current rate and the second current rate, and the SOC is not less than 20%, the first driving cooling control sub-process is executed.

[0209] Otherwise, return and execute S310 again.

[0210] S350. Check the average discharge current rate and SOC corresponding to the timestamp in S330; then, based on the check result, perform the following operations:

[0211] If the average discharge current rate corresponding to the timestamp in S330 is not lower than the first current rate, and the SOC is not lower than 20%, the second driving cooling control sub-process is executed.

[0212] Otherwise, return and execute S310 again.

[0213] It should be noted that generally, when the SOC is lower than 20%, the power will be limited and the vehicle will enter a limp state. At this time, the operating conditions are relatively mild and no cooling is required.

[0214] It should be further explained that if the average discharge current rate of the battery within 10 minutes is not lower than the first current rate, it indicates that the current operating conditions are more stringent than the previous conditions and require a higher cooling effect.

[0215] The first driving cooling control sub-process specifically includes the following contents:

[0216] Sa341. Set the SOC management strategy effective range to 20% to 100%.

[0217] Sa342. Set the current rate management strategy effective range to 0.15C~0.30C.

[0218] Sa343. Set the target water temperature of the coolant in the water-cooling unit to the manually preset 20th temperature threshold.

[0219] Sa344. Check the single cell temperature, battery pack average temperature, average discharge current rate, and SOC corresponding to the current timestamp; then, based on the check results, perform the following operations:

[0220] If there is a timestamp whose average discharge current rate is less than the second current rate, or the corresponding SOC is lower than 20%, or the corresponding maximum temperature of the single cell is not higher than the second temperature threshold, or the corresponding average temperature of the battery pack is not higher than the third temperature threshold, then the first driving cooling control sub-process is closed.

[0221] Otherwise, return and execute Sa344 again.

[0222] The second driving cooling control sub-process specifically includes the following contents:

[0223] Sa351. Set the SOC management strategy effective range to 20% to 100%.

[0224] Sa352. Set the current rate management strategy effective range to 0.30C~0.80C and above 0.80C.

[0225] Sa353. Set the target water temperature of the coolant in the water-cooling unit to the manually preset 21st temperature threshold.

[0226] Sa353. Check the single cell temperature, battery pack average temperature, average discharge current rate, and SOC corresponding to the current timestamp; then, based on the check results, perform the following operations:

[0227] If there is a timestamp whose average discharge current rate is less than the second current rate, or the corresponding SOC is lower than 20%, or the corresponding maximum temperature of the single cell is not higher than the third temperature threshold, or the corresponding average temperature of the battery pack is not higher than the manually preset fourth temperature threshold, then the second driving cooling control sub-process is closed.

[0228] Otherwise, return and execute Sa351 again.

[0229] S400. Execute the charging cooling control sub-process.

[0230] In this specific embodiment, the charging cooling control sub-process in S400 specifically includes the following steps:

[0231] S410. Collect the charging current rate, SOC, the temperature of each single cell in the battery pack, and the average temperature of the battery pack in real time; then timestamp the collected charging current rate, SOC, single cell temperature, and average temperature of the battery pack according to the time of collection, and arrange them in increasing order of the timestamps.

[0232] S420. Check the single cell temperature and battery pack average temperature corresponding to each timestamp in real time; then perform the following operations based on the check results:

[0233] If there is a timestamp corresponding to which the highest temperature of the single battery is not lower than the third temperature threshold, and the average temperature of the battery pack corresponding to this timestamp is not lower than the manually preset seventh temperature threshold, then S430 is executed.

[0234] If there is a timestamp corresponding to which the highest temperature of the single battery is not lower than the second temperature threshold, and the average temperature of the battery pack corresponding to this timestamp is not lower than the third temperature threshold, then S440 is executed.

[0235] If there is a timestamp corresponding to which the highest temperature of the single battery is not lower than the first temperature threshold, and the average temperature of the battery pack corresponding to this timestamp is not lower than the second temperature threshold, then S450 is executed.

[0236] Otherwise, return and execute S410 again.

[0237] S430. Check the charging current rate and SOC corresponding to the timestamp in S420; then, based on the check results, perform the following operations:

[0238] If the charging current rate corresponding to the timestamp in S420 is higher than the manually preset fourth current rate, and the SOC is not higher than 30%, the first charging and cooling control sub-process is executed.

[0239] Otherwise, return and execute S410 again.

[0240] It should be noted that the corresponding working conditions at this time are the most stringent.

[0241] S440. Check the charging current rate and SOC corresponding to the timestamp in S420; then, based on the check results, perform the following operations:

[0242] If the charging current rate corresponding to the timestamp in S420 is between the third current rate and the fourth current rate, and the SOC is between 30% and 80%, the second driving cooling control sub-process is executed.

[0243] Otherwise, return and execute S410 again.

[0244] S450. Check the charging current rate and SOC corresponding to the timestamp in S420; then, based on the check results, perform the following operations:

[0245] If the charging current rate corresponding to the timestamp in S420 is less than the third current rate, and the SOC is between 80% and 100%, the third driving cooling control sub-process is executed.

[0246] It should be noted that the working conditions at this time are relatively mild and the demand for cooling capacity is not high. Subsequently, the cooling effect can be achieved by simply setting the target water temperature of the coolant in the water-cooled unit to the manually preset 20th temperature threshold.

[0247] Otherwise, return and execute S410 again.

[0248] The first charging and cooling control sub-process specifically includes the following steps:

[0249] Sa431. Set the SOC management strategy effective range to 0% to 30%.

[0250] Sa432. Set the current rate management strategy effective range to 0.80C and above.

[0251] Sa433. Set the target water temperature of the coolant in the water-cooling unit to the 21st temperature threshold.

[0252] Sa434. Check the single cell temperature and battery pack temperature corresponding to the current timestamp; then, based on the check results, perform the following operations:

[0253] If there is a timestamp corresponding to a single battery whose highest temperature is not higher than the manually preset fourth temperature threshold, or the corresponding battery pack temperature is not higher than the manually preset eighth temperature threshold, the first driving cooling control sub-process is closed.

[0254] Otherwise, return and execute Sa434 again.

[0255] The second charging and cooling control sub-process specifically includes the following steps:

[0256] Sa441. Set the SOC management strategy effective range to 30% to 80%.

[0257] Sa442. Set the current rate management strategy effective range to 0.50C~0.80C.

[0258] Sa443. Set the target water temperature of the coolant in the water-cooling unit to the 21st temperature threshold.

[0259] Sa444. Check the single cell temperature and battery pack temperature corresponding to the current timestamp; then, based on the check results, perform the following operations:

[0260] If there is a timestamp corresponding to a single battery whose highest temperature is not higher than the manually preset sixth temperature threshold, or the corresponding battery pack temperature is not higher than the fourth temperature threshold, the second driving cooling control sub-process is closed.

[0261] Otherwise, return and execute Sa444 again.

[0262] The third charging and cooling control sub-process specifically includes the following steps:

[0263] Sa451. Set the SOC management strategy effective range to 80% to 100%.

[0264] Sa452. Set the current rate management strategy effective range to 0.10C~0.50C.

[0265] Sa453. Set the target water temperature of the coolant in the water-cooling unit to the manually preset 20th temperature threshold.

[0266] Sa454. Check the single cell temperature and battery pack temperature corresponding to the current timestamp; then, based on the check results, perform the following operations:

[0267] If there is a timestamp corresponding to a single battery whose highest temperature is not higher than the manually preset fifth temperature threshold, or the corresponding battery pack temperature is not higher than the sixth temperature threshold, then the third driving cooling control sub-process is closed.

[0268] Otherwise, return and execute Sa454 again.

[0269] S500. Execute the driving heating control sub-process.

[0270] In this specific embodiment, the driving heating control sub-process in S500 specifically includes the following steps:

[0271] S510. Collect the discharge current rate, SOC, the temperature of each single cell in the battery pack, and the average temperature of the battery pack in real time; then timestamp the collected discharge current rate, SOC, single cell temperature, and average temperature of the battery pack according to the time of collection, and arrange them in increasing order of the timestamps.

[0272] S520. Check the single cell temperature and battery pack average temperature corresponding to each timestamp in real time; then perform the following operations based on the check results:

[0273] If there is a timestamp corresponding to which the lowest temperature of the single battery is not higher than the manually preset tenth temperature threshold, and the average temperature of the battery pack corresponding to this timestamp is not higher than the manually preset ninth temperature threshold, then S530 is executed.

[0274] It should be noted that when heating while driving, the battery will generate heat autonomously due to discharge behavior. When the SOC is above a certain value or the operating power is high, the heating temperature threshold and target water temperature can be appropriately lowered.

[0275] S530. Check the SOC corresponding to the timestamp in S520; then, based on the check result, perform the following operations:

[0276] If the SOC corresponding to the timestamp in S520 is not less than 30%, the driving heating control sub-process is executed.

[0277] Otherwise, return and execute S510 again.

[0278] The driving heating control sub-process specifically includes the following steps:

[0279] S511. Set the SOC management policy effective range to 30% to 100%.

[0280] S512. Set the current rate management strategy effective range to 0.15C to 0.80C and above.

[0281] S513. Set the target water temperature of the coolant in the water-cooling unit to a manually preset 23rd temperature threshold.

[0282] S514. For each discharge current rate, calculate the arithmetic mean within the 60 minutes before the corresponding timestamp to obtain the average discharge current rate corresponding to this timestamp; if the time from the corresponding timestamp to the starting time point is less than 60 minutes, calculate the average discharge current rate between the corresponding timestamp and the starting time point; then mark the calculated average discharge current rate with the corresponding timestamp and arrange them in increasing order of timestamps.

[0283] S515. Check the single cell temperature, battery pack average temperature, average discharge current rate, and SOC corresponding to the current timestamp; then, based on the check results, perform the following operations:

[0284] If there is a timestamp whose corresponding average discharge current rate is less than the second current rate, or the corresponding SOC is lower than 30%, or the corresponding lowest temperature of the single cell is not lower than the ninth temperature threshold, or the corresponding average temperature of the battery pack is not lower than the manually preset eleventh temperature threshold, then the driving heating control sub-process is closed.

[0285] Otherwise, return and execute S510 again.

[0286] S600. Execute the charging and heating control sub-process.

[0287] In this specific embodiment, the charging heating control sub-process in S600 specifically includes the following steps:

[0288] S610. Real-time collection of the charging current rate, SOC, temperature of each single cell in the battery pack, and average temperature of the battery pack that the charging pile can provide; then the collected charging current rate, SOC, temperature of each single cell, and average temperature of the battery pack that the charging pile can provide are timestamped at the time of collection and arranged in increasing order of timestamps.

[0289] S620. Check the single cell temperature and battery pack average temperature corresponding to each timestamp in real time; then, based on the check results, perform the following operations:

[0290] If there is a timestamp corresponding to which the lowest temperature of the single battery is not higher than the manually preset thirteenth temperature threshold, and the average temperature of the battery pack corresponding to this timestamp is not higher than the manually preset twelfth temperature threshold, then S630 is executed.

[0291] If there is a timestamp corresponding to which the lowest temperature of the single battery is not higher than the manually preset fourteenth temperature threshold, and the average temperature of the battery pack corresponding to this timestamp is not higher than the manually preset seventeenth temperature threshold, then S640 is executed.

[0292] If there is a timestamp corresponding to which the lowest temperature of the single battery is not higher than the manually preset fifteenth temperature threshold, and the average temperature of the battery pack corresponding to this timestamp is not higher than the manually preset eighteenth temperature threshold, then S650 is executed.

[0293] Otherwise, return and execute S610 again.

[0294] It's important to note that, similar to charging cooling, charging heating also needs to consider the impact of SOC. The lower the initial SOC during charging, the greater the total heat generated, and the less heat required from the heating circuit. Lowering the heating temperature threshold and target water temperature can not only reduce energy consumption but also avoid the phenomenon of heating at the beginning and cooling at the end of the charging cycle, which can waste energy.

[0295] S630. Check whether the charging pile corresponding to the timestamp in S620 can provide charging current rate and SOC; then, based on the check result, perform the following operations:

[0296] If the charging pile corresponding to the timestamp in S620 can provide a charging current rate higher than the fourth current rate and the SOC is not higher than 30%, the first charging and heating control sub-process is executed.

[0297] Otherwise, return and execute S610 again.

[0298] S640. Check whether the charging pile corresponding to the timestamp in S620 can provide charging current rate and SOC; then, based on the check result, perform the following operations:

[0299] If the charging pile corresponding to the timestamp in S620 can provide a charging current rate between the third current rate and the fourth current rate, and the SOC is between 30% and 80%, the second charging and heating control sub-process is executed.

[0300] Otherwise, return and execute S610 again.

[0301] S650. Check whether the charging pile corresponding to the timestamp in S620 can provide charging current rate and SOC; then, based on the check result, perform the following operations:

[0302] If the charging pile corresponding to the timestamp in S620 can provide a charging current rate that is less than the third current rate, and the SOC is between 80% and 100%, the third charging and heating control sub-process is executed.

[0303] Otherwise, return and execute S610 again.

[0304] It should be noted that the actual situation corresponding to the third charging and heating control sub-process is: if the charging power is low and the initial SOC entering charging is high, the heating circuit needs to provide most of the heating power.

[0305] The first charging and heating control sub-process specifically includes the following steps:

[0306] Sa631. Set the SOC management strategy effective range to 0% to 30%.

[0307] Sa632. Set the effective range of the current rate management strategy to the charging current rate that the charging pile can provide.

[0308] Sa633. Set the target water temperature of the coolant in the water-cooling unit to the manually preset 22nd temperature threshold.

[0309] Sa634. Check the single cell temperature and battery pack temperature corresponding to the current timestamp; then, based on the check results, perform the following operations:

[0310] If there is a timestamp corresponding to a single battery whose lowest temperature is not lower than the manually preset twelfth temperature threshold, and the corresponding battery pack temperature is not lower than the manually preset sixteenth temperature threshold, then the first charging and heating control sub-process is closed.

[0311] Otherwise, return and execute Sa634 again.

[0312] The second charging and heating control sub-process specifically includes the following steps:

[0313] Sa641. Set the SOC management strategy effective range to 30% to 80%.

[0314] Sa642. Set the effective range of the current rate management strategy to the charging current rate that the charging pile can provide.

[0315] Sa643. Set the target water temperature of the coolant in the water-cooling unit to the 22nd temperature threshold.

[0316] Sa644. Check the single cell temperature and battery pack temperature corresponding to the current timestamp; then, based on the check results, perform the following operations:

[0317] If there is a timestamp corresponding to a single battery whose lowest temperature is not lower than the manually preset thirteenth temperature threshold, and the corresponding battery pack temperature is not lower than the manually preset twelfth temperature threshold, then the second charging and heating control sub-process is closed.

[0318] Otherwise, return and execute Sa644 again.

[0319] The third charging and heating control sub-process specifically includes the following steps:

[0320] Sa651. Set the SOC management strategy effective range to 80% to 100%.

[0321] Sa652. Set the effective range of the current rate management strategy to the charging current rate that the charging pile can provide.

[0322] Sa653. Set the target water temperature of the coolant in the water-cooling unit to the 22nd temperature threshold.

[0323] Sa654. Check the single cell temperature and battery pack temperature corresponding to the current timestamp; then, based on the check results, perform the following operations:

[0324] If there is a timestamp corresponding to a single battery whose lowest temperature is not lower than the manually preset fourteenth temperature threshold, or the corresponding battery pack temperature is not lower than the manually preset seventeenth temperature threshold, the third charging and heating control sub-process is closed.

[0325] Otherwise, return and execute Sa654 again.

[0326] S700. Execute the driving temperature average self-circulation control sub-process.

[0327] In this specific embodiment, the driving temperature average self-circulation control sub-process in S700 specifically includes the following steps:

[0328] S710. Collect the charging current rate, SOC, the temperature of each single cell in the battery pack, and the average temperature of the battery pack in real time; then timestamp the collected charging current rate, SOC, single cell temperature, and average temperature of the battery pack according to the time of collection, and arrange them in increasing order of the timestamps.

[0329] S720. Check whether cooling and heating are currently on; then make the following operations based on the check results.

[0330] If cooling is not currently on and heating is not currently on, execute S730.

[0331] If cooling is currently on, or heating is on, the process returns to and executes S720 again.

[0332] S730. Check the SOC, single cell temperature, and average battery pack temperature corresponding to each timestamp in real time; then, based on the check results, perform the following operations:

[0333] If there is a timestamp corresponding to an SOC not less than 20%, and the difference between the highest temperature of the single cell and the lowest temperature of the single cell is not less than the manually preset 24th temperature threshold, the driving temperature averaging self-circulation control sub-process is executed.

[0334] Otherwise, return and execute S710 again.

[0335] The driving temperature average self-circulation control sub-process specifically includes the following steps:

[0336] Sa731. Set the SOC management strategy effective range to 20% to 100%.

[0337] Sa732. Set the current rate management strategy effective range to 0.15C to 0.80C and above.

[0338] Sa733. Start the water cycle.

[0339] Sa734. For each discharge current rate, calculate the arithmetic mean within the 60 minutes before the corresponding timestamp to obtain the average discharge current rate corresponding to this timestamp; if the time from the corresponding timestamp to the starting time point is less than 60 minutes, calculate the average discharge current rate between the corresponding timestamp and the starting time point; then mark the calculated average discharge current rate with the corresponding timestamp and arrange them in increasing order of timestamps.

[0340] Sa735. Check the single cell temperature, battery pack average temperature, average discharge current rate, and SOC corresponding to the current timestamp; then, based on the check results, perform the following operations:

[0341] If there is a timestamp corresponding to an SOC lower than 20%, or the difference between the corresponding highest temperature of the single cell battery and the lowest temperature of the single cell battery is not higher than the manually preset 25th temperature threshold, or the average discharge current rate is less than the second current rate, or the single cell battery temperature and the average temperature of the battery pack reach the manually preset cooling / heating judgment conditions, then the driving average temperature self-circulation control sub-process will be closed.

[0342] Otherwise, return and execute Sa734 again.

[0343] S800. Execute the charging temperature equalization self-circulation control sub-process.

[0344] In this specific embodiment, the charging temperature equalization self-circulation control sub-process in S800 specifically includes the following steps:

[0345] S810. Collect the charging current rate, SOC, the temperature of each single cell in the battery pack, and the average temperature of the battery pack in real time; then timestamp the collected charging current rate, SOC, single cell temperature, and average temperature of the battery pack according to the time of collection, and arrange them in increasing order of the timestamps.

[0346] S820. Check whether cooling and heating are currently on; then make the following operations based on the check results.

[0347] If cooling is not currently on and heating is not currently on, execute S830.

[0348] If cooling is currently on, or heating is on, the process returns to and executes S820 again.

[0349] S830. Check the SOC, single cell temperature, and average battery pack temperature corresponding to each timestamp in real time; then, based on the check results, perform the following operations:

[0350] If there is a timestamp corresponding to the SOC not higher than 80%,

[0351] If the difference between the highest temperature of the single battery and the lowest temperature of the single battery is not lower than the twenty-fourth temperature threshold, the charging temperature equalization self-circulation control sub-process is executed.

[0352] Otherwise, return and execute S810 again.

[0353] The charging temperature equalization self-circulation control sub-process specifically includes the following steps:

[0354] Sa831. Set the SOC management strategy effective range to 0% to 80%.

[0355] Sa832. Start the water cycle.

[0356] Sa833. Check the single cell temperature, battery pack average temperature, average charge current rate, and SOC corresponding to the current timestamp; then, based on the check results, perform the following operations:

[0357] If there is a timestamp corresponding to an SOC higher than 80%, or the difference between the corresponding maximum temperature of the single cell and the minimum temperature of the single cell is not higher than the 25th temperature threshold, or the temperature of the single cell and the average temperature of the battery pack reach the manually preset judgment conditions for turning on cooling / heating, then the current charging temperature averaging self-circulation control sub-process will be closed.

[0358] Otherwise, return and execute Sa834 again.

[0359] It should be noted that the reason for both driving and charging temperature-averaging self-circulation is the same: to prevent the maximum temperature difference of the battery cells from continuing to increase during charging, discharging, or thermal management, a temperature-averaging self-circulation function is required to keep the temperature of each battery cell basically consistent to avoid damaging the battery life. When cooling and heating are not turned on, the temperature-averaging self-circulation, i.e., water circulation, is started when the difference between the highest temperature of a single cell and the lowest temperature of a single cell is no higher than the 24th temperature threshold, and the circulation is stopped until the temperature difference falls below the 25th temperature threshold.

[0360] In this specific embodiment, the first temperature threshold is 34°C; the second temperature threshold is 30°C; the third temperature threshold is 26°C; the fourth temperature threshold is 24°C; the fifth temperature threshold is 32°C; the sixth temperature threshold is 28°C; the seventh temperature threshold is 22°C; the eighth temperature threshold is 20°C; the ninth temperature threshold is 5°C; the tenth temperature threshold is 2°C; the eleventh temperature threshold is 8°C; the twelfth temperature threshold is 20°C; the thirteenth temperature threshold is 18°C; the fourteenth temperature threshold is 14°C; the fifteenth temperature threshold is 10°C; the sixteenth temperature threshold is 22°C; the seventeenth temperature threshold is 16°C; the eighteenth temperature threshold is 12°C; the twentieth temperature threshold is 20°C; the twenty-first temperature threshold is 15°C; the twenty-second temperature threshold is 45°C; the twenty-third temperature threshold is 40°C; the twenty-fourth temperature threshold is 8°C; and the twenty-fifth temperature threshold is 5°C.

[0361] In this specific embodiment, the first current magnification is 0.30C; the second current magnification is 0.15C; the third current magnification is 0.50C; and the fourth current magnification is 0.80C.

[0362] In order to further demonstrate the technical effects of the present invention, this specific embodiment also includes an example based on an experiment, and the corresponding experimental process data and result data are disclosed as follows:

[0363] For the convenience of expression, the concepts in the present invention are represented by symbols below: Tmax is the maximum temperature of the single cell.

[0364] The standard thermal management strategy of the power battery system in this experiment stipulates that cooling should be entered when Tmax ≥ 28°C and cooling should be exited when Tmax ≤ 25°C.

[0365] The initial parameters of this experiment are: target water temperature 15°C, initial water temperature 25°C, total coolant volume 10L, density 1.1kg / L, coolant specific heat 3.3kJ / kg.K, battery specific heat 1kJ / kg.K, initial temperature 38°C, battery weight 200kg.

[0366] According to the initial conditions, the energy required to reduce the coolant to the target water temperature is 1.1*10*(25-15)*3.3=363kJ≈0.1kWh, and the energy required for power battery cooling is 200*1*(38-28)=2000kJ≈0.56kWh.

[0367] If the working conditions are relatively mild at this time, the target water temperature can be set to 20℃, and cooling can be started when Tmax≥38℃ and exited when Tmax≤35℃. The energy required to lower the coolant to the target water temperature is 1.1*10*(25-20)*3.3=363kJ≈0.05kWh.

[0368] When the battery Tmax = 35 ° C, this solution can reduce 0.1-0.05+0.56=0.61kWh compared with the original solution. If the battery energy density is 150Wh / kg, the power is 150*200=30000Wh=30kWh.

[0369] Through simple calculation, it can be known that the adoption of the technical solution of the present invention can save approximately 0.61 / 30*100%≈2.03% of the SOC.

[0370] In the foregoing detailed description, various features are grouped together in a single embodiment to simplify the disclosure. This method of disclosure should not be interpreted as reflecting an intention that embodiments of the claimed subject matter require more features than are expressly recited in each claim. On the contrary, as reflected in the appended claims, the invention comprises less than all the features of any individual disclosed embodiment. The appended claims are hereby expressly incorporated into the detailed description, with each claim standing on its own as a separate preferred embodiment of the invention.

[0371] The above description of the disclosed embodiments is intended to enable any person skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other embodiments without departing from the spirit and scope of the present disclosure. Therefore, the present disclosure is not limited to the embodiments presented herein but is intended to be accorded the widest scope consistent with the principles and novel features disclosed herein.

[0372] The foregoing description includes examples of one or more embodiments. Of course, it is not possible to describe all possible combinations of components or methods for the purposes of describing the above embodiments, but one of ordinary skill in the art will recognize that the various embodiments may be further combined and arranged. Therefore, the embodiments described herein are intended to encompass all such changes, modifications and variations that fall within the scope of the appended claims. Furthermore, to the extent the term "comprising" is used in the specification or claims, the term is intended to be encompassed in a manner similar to the term "including," as explained in terms of "including," used as a transitional word in the claims. Furthermore, any use of the term "or" in the specification of the claims is intended to mean a "non-exclusive or."

[0373] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A power battery system temperature control method, characterized in that: The following steps are involved: S100 obtains the current vehicle motion state, temperature control state; the vehicle motion state includes driving state, charging state; the temperature control state includes cooling state, heating state, and temperature self-circulation state; S200. Perform the following operations based on the vehicle motion state and the temperature control state: If the vehicle motion state is the driving state, and the temperature control state is the cooling state, executing S300; If the vehicle motion state is the charging state and the temperature control state is the cooling state, executing S400; If the vehicle motion state is the driving state, and the temperature control state is the heating state, executing S500; If the vehicle motion state is the charging state, and the temperature control state is the heating state, executing S600; If the vehicle motion state is the driving state, and the temperature control state is the temperature-averaging self-circulating state, then execute S700; If the vehicle motion state is the charging state, and the temperature control state is the temperature-averaging self-circulation state, execute S800; S300. Execute the driving cooling control sub-process; S400. Execute the charging cooling control sub-process; S500. Execute the driving heating control sub-process; S600. Execute charging and heating control sub-process; S700. Execute the driving temperature self-circulation control sub-process; S800. Execute the charging temperature self-circulation control sub-process; The driving cooling control sub-process in S300 specifically includes the following steps: S310. Real-time collection of the discharge current rate, SOC, cell temperature of each cell in the battery pack, and the average temperature of the battery pack; then timestamping the collected discharge current rate, SOC, cell temperature, and average temperature of the battery pack according to the time of collection, and arranging them in increasing order of the timestamps; S320. For each of the discharge current magnifications, calculate the arithmetic mean within the 10 minutes before the corresponding timestamp to obtain the average discharge current magnification corresponding to the timestamp; If the time from the corresponding timestamp to the starting time point is less than 10 minutes, then calculating the average discharge current rate between the corresponding timestamp and the starting time point; Then, the calculated average discharge current rate is marked with the corresponding timestamp and arranged in increasing order of the timestamp; S330. Check the temperature of the single cell and the average temperature of the battery pack corresponding to each timestamp in real time; then perform the following operations based on the check results: If there is a timestamp corresponding to which the highest temperature of the single battery cell is not lower than a manually preset first temperature threshold, and the average temperature of the battery pack corresponding to the timestamp is not lower than a manually preset second temperature threshold, then execute S340; If there is a timestamp corresponding to which the highest temperature of the single battery cell is not lower than the second temperature threshold, and the average temperature of the battery pack corresponding to the timestamp is not lower than the manually preset third temperature threshold, then execute S350; Otherwise, return and execute S310 again; S340. Check the average discharge current rate and the SOC corresponding to the timestamp in S330; then perform the following operations based on the check result: If the average discharge current rate corresponding to the timestamp in S330 is between the manually preset first current rate and the second current rate, and the SOC is not less than 20%, then the first driving cooling control sub-process is executed; Otherwise, return and execute S310 again; S350. Check the average discharge current rate and the SOC corresponding to the timestamp in S330; then perform the following operations based on the check result: If the average discharge current rate corresponding to the timestamp in S330 is not lower than the first current rate, and the SOC is not lower than 20%, then executing the second driving cooling control sub-process; Otherwise, return and execute S310 again; The first driving cooling control sub-process specifically includes the following contents: Sa341. Set the SOC management strategy effective range to 20% to 100%; Sa342. Set the current rate management strategy effective range to 0.15C ~ 0.30C; Sa343. The target water temperature of the water-cooled unit coolant is set to the manually preset twentieth temperature threshold; Sa344. Check the single cell temperature, the average temperature of the battery pack, the average discharge current rate, and the SOC corresponding to the current timestamp; then perform the following operations based on the check results: If there is a timestamp corresponding to which the average discharge current rate is less than the second current rate, or the corresponding SOC is lower than 20%, or the corresponding maximum temperature of the single battery is not higher than the second temperature threshold, or the corresponding average temperature of the battery pack is not higher than the third temperature threshold, then the first driving cooling control sub-process is closed; Otherwise, return and execute Sa344 again; The second driving cooling control sub-process specifically includes the following contents: Sa351. Set the SOC management strategy effective range to 20% to 100%; Sa352. Set the current rate management strategy effective range to 0.30C to 0.80C and above 0.80C; Sa353. The target water temperature of the water-cooled unit coolant is set to the manually preset 21st temperature threshold; Sa353. Check the single cell temperature, the average temperature of the battery pack, the average discharge current rate, and the SOC corresponding to the current timestamp; then perform the following operations based on the check results: If there is a timestamp corresponding to which the average discharge current rate is less than the second current rate, or the corresponding SOC is lower than 20%, or the corresponding maximum temperature of the single battery is not higher than the third temperature threshold, or the corresponding average temperature of the battery pack is not higher than the manually preset fourth temperature threshold, then the second driving cooling control sub-process is closed; Otherwise, return and execute Sa351 again.

2. The power battery system temperature control method according to claim 1, characterized in that: The charging cooling control sub-process in S400 specifically includes the following steps: S410. Collecting the charging current rate, SOC, the temperature of each battery cell in the battery pack, and the average temperature of the battery pack in real time; then timestamping the collected charging current rate, SOC, the temperature of each battery cell, and the average temperature of the battery pack according to the time of collection, and arranging them in increasing order of the timestamps; S420. Check the temperature of the single battery cell and the average temperature of the battery pack corresponding to each timestamp in real time; then perform the following operations based on the check results: If there is a timestamp corresponding to which the highest temperature of the single battery cell is not lower than the third temperature threshold, and the average temperature of the battery pack corresponding to the timestamp is not lower than the manually preset seventh temperature threshold, then execute S430; If there is a timestamp corresponding to which the highest temperature of the single battery cell is not lower than the second temperature threshold, and the average temperature of the battery pack corresponding to the timestamp is not lower than the third temperature threshold, executing S440; If there is a timestamp corresponding to which the highest temperature of the single battery cell is not lower than the first temperature threshold, and the average temperature of the battery pack corresponding to the timestamp is not lower than the second temperature threshold, executing S450; Otherwise, return and execute S410 again; S430. Check the charging current rate and the SOC corresponding to the timestamp in S420; then perform the following operations based on the check result: If the charging current rate corresponding to the timestamp in S420 is higher than a manually preset fourth current rate, and the SOC is not higher than 30%, executing the first charging and cooling control sub-process; Otherwise, return and execute S410 again; S440. Check the charging current rate and the SOC corresponding to the timestamp in S420; then perform the following operations based on the check result: If the charging current rate corresponding to the timestamp in S420 is between the third current rate and the fourth current rate, and the SOC is between 30% and 80%, then executing the second charging and cooling control sub-process; Otherwise, return and execute S410 again; S450. Check the charging current rate and the SOC corresponding to the timestamp in S420; then perform the following operations based on the check result: If the charging current rate corresponding to the timestamp in S420 is less than the third current rate, and the SOC is between 80% and 100%, executing the third charging and cooling control sub-process; Otherwise, return and execute S410 again; The first charging and cooling control sub-process specifically includes the following steps: Sa431. Set the SOC management strategy effective range to 0% to 30%; Sa432. Set the current rate management strategy effective range to 0.80C and above; Sa433. The target water temperature of the water-cooling unit coolant is set to the 21st temperature threshold; Sa434. Check the single cell temperature and the battery pack temperature corresponding to the current timestamp; then perform the following operations based on the check results: If there is a timestamp corresponding to which the highest temperature of the single battery cell is not higher than the manually preset fourth temperature threshold, or the corresponding battery pack temperature is not higher than the manually preset eighth temperature threshold, then closing the first driving cooling control sub-process; Otherwise, return and execute Sa434 again; The second charging and cooling control sub-process specifically includes the following steps: Sa441. Set the SOC management strategy effective range to 30% to 80%; Sa442. Set the current rate management strategy effective range to 0.50C ~ 0.80C; Sa443. Set the target water temperature of the water-cooling unit coolant to the twenty-first temperature threshold; Sa444. Check the single cell temperature and the battery pack temperature corresponding to the current timestamp; then perform the following operations based on the check results: If the highest temperature of the single battery cell corresponding to a timestamp is not higher than the manually preset sixth temperature threshold, or the corresponding battery pack temperature is not higher than the fourth temperature threshold, then closing the second driving cooling control sub-process; Otherwise, return and execute Sa444 again; The third charging and cooling control sub-process specifically includes the following steps: Sa451. Set the SOC management policy effective range to 80% to 100%; Sa452. Set the current rate management strategy effective range to 0.10C to 0.50C; Sa453. The target water temperature of the water-cooled unit coolant is set to the manually preset twentieth temperature threshold; Sa454. Check the single cell temperature and the battery pack temperature corresponding to the current timestamp; then perform the following operations based on the check results: If the highest temperature of the single battery cell corresponding to a timestamp is not higher than the manually preset fifth temperature threshold, or the corresponding battery pack temperature is not higher than the sixth temperature threshold, then the third charging and cooling control sub-process is closed; Otherwise, return and execute Sa454 again.

3. The power battery system temperature control method according to claim 2, characterized in that: The driving heating control sub-process in S500 specifically includes the following steps: S510. Collecting in real time the discharge current rate, SOC, the temperature of each battery cell in the battery pack, and the average temperature of the battery pack; then timestamping the collected discharge current rate, SOC, battery cell temperature, and average temperature of the battery pack according to the time of collection, and arranging them in increasing order of the timestamps; S520. Check the temperature of the single battery cell and the average temperature of the battery pack corresponding to each timestamp in real time; then perform the following operations based on the check results: If there is a timestamp corresponding to which the lowest temperature of the single battery cell is not higher than the manually preset tenth temperature threshold, and the average temperature of the battery pack corresponding to this timestamp is not higher than the manually preset ninth temperature threshold, then execute S530; S530. Check the SOC corresponding to the timestamp in S520; then, based on the check result, perform the following operations: If the SOC corresponding to the timestamp in S520 is not less than 30%, executing the driving heating control sub-process; Otherwise, return and execute S510 again; The vehicle heating control sub-process specifically includes the following steps: S511. Set the SOC management policy effective range to 30% to 100%; S512. Set the current rate management strategy effective range to 0.15C to 0.80C and above; S513. The target water temperature of the water-cooling unit coolant is set to the manually preset 23rd temperature threshold; S514. For each of the discharge current magnifications, calculate the arithmetic mean within the 60 minutes before the corresponding timestamp to obtain the average discharge current magnification corresponding to the timestamp; If the time from the corresponding timestamp to the starting time point is less than 60 minutes, then calculating the average discharge current rate between the corresponding timestamp and the starting time point; Then, the calculated average discharge current rate is marked with the corresponding timestamp and arranged in increasing order of the timestamp; S515. Check the single cell temperature, the average temperature of the battery pack, the average discharge current rate, and the SOC corresponding to the current timestamp; then perform the following operations based on the check results: If there is a timestamp corresponding to which the average discharge current rate is less than the second current rate, or the corresponding SOC is lower than 30%, or the corresponding lowest temperature of the single battery is not lower than the ninth temperature threshold, or the corresponding average temperature of the battery pack is not lower than the manually preset eleventh temperature threshold, then the driving heating control sub-process is closed; Otherwise, return and execute S510 again.

4. The power battery system temperature control method according to claim 3, characterized in that: The charging heating control sub-process in S600 specifically includes the following steps: S610. Real-time collection of charging current rate, SOC, cell temperature of each cell in the battery pack, and average temperature of the battery pack provided by the charging pile; then the collected charging current rate, SOC, cell temperature, and average temperature of the battery pack provided by the charging pile are timestamped at the time of collection and arranged in ascending order of the timestamps; S620. Check the single cell temperature and the average temperature of the battery pack corresponding to each timestamp in real time; then perform the following operations based on the check results: If there is a timestamp corresponding to which the lowest temperature of the single battery cell is not higher than the manually preset thirteenth temperature threshold, and the average temperature of the battery pack corresponding to the timestamp is not higher than the manually preset twelfth temperature threshold, execute S630; If there is a timestamp corresponding to which the lowest temperature of the single battery cell is not higher than the manually preset fourteenth temperature threshold, and the battery pack average temperature corresponding to the timestamp is not higher than the manually preset seventeenth temperature threshold, execute S640; If there is a timestamp corresponding to which the lowest temperature of the single battery cell is not higher than the manually preset fifteenth temperature threshold, and the average temperature of the battery pack corresponding to this timestamp is not higher than the manually preset eighteenth temperature threshold, then execute S650; Otherwise, return and execute S610 again; S630. Check whether the charging pile corresponding to the timestamp in S620 can provide the charging current rate and the SOC; then, based on the check result, perform the following operations: If the charging pile corresponding to the timestamp in S620 can provide a charging current rate higher than the fourth current rate, and the SOC is not higher than 30%, then executing the first charging and heating control sub-process; Otherwise, return and execute S610 again; S640. Check whether the charging pile corresponding to the timestamp in S620 can provide the charging current rate and the SOC; then perform the following operations based on the check result: If the charging pile corresponding to the timestamp in S620 can provide a charging current rate between the third current rate and the fourth current rate, and the SOC is between 30% and 80%, then execute the second charging and heating control sub-process; Otherwise, return and execute S610 again; S650. Check whether the charging pile corresponding to the timestamp in S620 can provide the charging current rate and the SOC; then perform the following operations based on the check result: If the charging current rate provided by the charging pile corresponding to the timestamp in S620 is less than the third current rate, and the SOC is between 80% and 100%, then executing the third charging and heating control sub-process; Otherwise, return and execute S610 again; The first charging and heating control sub-process specifically includes the following steps: Sa631. Set the SOC management strategy effective range to 0% to 30%; Sa632. Set the current rate management strategy effective range to the charging current rate that the charging pile can provide; Sa633. The target water temperature of the water-cooled unit coolant is set to the manually preset 22nd temperature threshold; Sa634. Check the single cell temperature and the battery pack temperature corresponding to the current timestamp; then perform the following operations based on the check results: If there is a timestamp corresponding to which the lowest temperature of the single battery cell is not lower than the manually preset twelfth temperature threshold, and the corresponding battery pack temperature is not lower than the manually preset sixteenth temperature threshold, then closing the first charging and heating control sub-process; Otherwise, return and execute Sa634 again; The second charging and heating control sub-process specifically includes the following steps: Sa641. Set the SOC management policy effective range to 30% to 80%; Sa642. Set the current rate management strategy effective range to the charging current rate that the charging pile can provide; Sa643. Set the target water temperature of the water-cooling unit coolant to the twenty-second temperature threshold; Sa644. Check the single cell temperature and the battery pack temperature corresponding to the current timestamp; then perform the following operations based on the check results: If there is a timestamp corresponding to which the lowest temperature of the single battery cell is not lower than a manually preset thirteenth temperature threshold, and the corresponding battery pack temperature is not lower than a manually preset twelfth temperature threshold, then closing the second charging and heating control sub-process; Otherwise, return and execute Sa644 again; The third charging and heating control sub-process specifically includes the following steps: Sa651. Set the SOC management policy effective range to 80% to 100%; Sa652. Set the current rate management strategy effective range to the charging current rate that the charging pile can provide; Sa653. Set the target water temperature of the water-cooling unit coolant to the twenty-second temperature threshold; Sa654. Check the single cell temperature and the battery pack temperature corresponding to the current timestamp; then perform the following operations based on the check results: If there is a time stamp corresponding to which the lowest temperature of the single battery cell is not lower than the manually preset fourteenth temperature threshold, or the corresponding battery pack temperature is not lower than the manually preset seventeenth temperature threshold, then the third charging and heating control sub-process is closed; Otherwise, return and execute Sa654 again.

5. The power battery system temperature control method according to claim 4, characterized in that: The driving temperature averaging self-circulation control sub-process in S700 specifically includes the following steps: S710. Collecting the charging current rate, SOC, the temperature of each battery cell in the battery pack, and the average temperature of the battery pack in real time; then timestamping the collected charging current rate, SOC, the temperature of each battery cell, and the average temperature of the battery pack according to the time of collection, and arranging them in increasing order of the timestamps; S720. Check whether cooling and heating are currently turned on; then, based on the check results, perform the following operations: If cooling is not currently turned on and heating is not turned on, execute S730; If cooling is currently on, or heating is on, return to and execute S720 again; S730. Check the SOC, the single cell temperature, and the average temperature of the battery pack corresponding to each of the timestamps in real time; then perform the following operations based on the check results: If there is a time stamp corresponding to the SOC of not less than 20%, and the difference between the highest temperature of the single battery cell and the lowest temperature of the single battery cell is not less than the manually preset 24th temperature threshold, then executing the driving temperature averaging self-circulation control sub-process; Otherwise, return and execute S710 again; The driving temperature average self-circulation control sub-process specifically includes the following steps: Sa731. Set the SOC management strategy effective range to 20% to 100%; Sa732. Set the current rate management strategy effective range to 0.15C to 0.80C and above; Sa733. Start water circulation; Sa734. For each of the discharge current magnifications, calculate the arithmetic mean within the 60 minutes before the corresponding timestamp to obtain the average discharge current magnification corresponding to the timestamp; If the time from the corresponding timestamp to the starting time point is less than 60 minutes, then calculating the average discharge current rate between the corresponding timestamp and the starting time point; Then, the calculated average discharge current rate is marked with the corresponding timestamp and arranged in increasing order of the timestamp; Sa735. Check the single cell temperature, the average temperature of the battery pack, the average discharge current rate, and the SOC corresponding to the current timestamp; then perform the following operations based on the check results: If the SOC corresponding to one of the timestamps is lower than 20%, or the difference between the corresponding maximum temperature of the single cell and the minimum temperature of the single cell is not higher than the 25th manually preset temperature threshold, or the average discharge current rate is lower than the second current rate, or the single cell temperature and the average temperature of the battery pack meet the manually preset cooling / heating judgment conditions, then the driving temperature averaging self-circulation control sub-process is closed; Otherwise, return and execute Sa734 again.

6. The power battery system temperature control method according to claim 5, characterized in that: The charging temperature equalization self-circulation control sub-process in S800 specifically includes the following steps: S810. Collecting the charging current rate, SOC, the temperature of each battery cell in the battery pack, and the average temperature of the battery pack in real time; then timestamping the collected charging current rate, SOC, the temperature of each battery cell, and the average temperature of the battery pack according to the time of collection, and arranging them in increasing order of the timestamps; S820. Check whether cooling and heating are currently turned on; then, based on the check results, perform the following operations: If cooling is not currently turned on and heating is not turned on, execute S830; If cooling is currently on, or heating is on, return to and execute S820 again; S830. Check the SOC, the single cell temperature, and the average temperature of the battery pack corresponding to each of the timestamps in real time; then perform the following operations based on the check results: If there is a time stamp corresponding to the SOC not higher than 80%, and if the difference between the highest temperature of the single battery and the lowest temperature of the single battery is not lower than the twenty-fourth temperature threshold, then executing the charging temperature equalization self-circulation control sub-process; Otherwise, return and execute S810 again; The charging temperature equalization self-circulation control sub-process specifically includes the following steps: Sa831. Set the SOC management strategy effective range to 0% to 80%; Sa832. Start the water cycle; Sa833. Check the single cell temperature, the average temperature of the battery pack, the average charging current rate, and the SOC corresponding to the current timestamp; then perform the following operations based on the check results: If the SOC corresponding to one of the timestamps is higher than 80%, or the difference between the corresponding highest temperature of the single cell and the lowest temperature of the single cell is not higher than the 25th temperature threshold, or the temperature of the single cell and the average temperature of the battery pack reach the manually preset cooling / heating judgment condition, then the current charging temperature equalization self-circulation control sub-process is closed; Otherwise, return and execute Sa834 again.

7. The power battery system temperature control method according to claim 6, characterized in that: The first temperature threshold is 34°C; the second temperature threshold is 30°C; the third temperature threshold is 26°C; the fourth temperature threshold is 24°C; the fifth temperature threshold is 32°C; the sixth temperature threshold is 28°C; the seventh temperature threshold is 22°C; the eighth temperature threshold is 20°C; the ninth temperature threshold is 5°C; the tenth temperature threshold is 2°C; the eleventh temperature threshold is 8°C; the twelfth temperature threshold is 20°C; the thirteenth temperature threshold is 18°C; the fourteenth temperature threshold is 14°C; the fifteenth temperature threshold is 10°C; the sixteenth temperature threshold is 22°C; the seventeenth temperature threshold is 16°C; the eighteenth temperature threshold is 12°C; the twentieth temperature threshold is 20°C; the twenty-first temperature threshold is 15°C; the twenty-second temperature threshold is 45°C; the twenty-third temperature threshold is 40°C; the twenty-fourth temperature threshold is 8°C; and the twenty-fifth temperature threshold is 5°C.

8. The power battery system temperature control method according to claim 7, characterized in that: The first current magnification is 0.30C; the second current magnification is 0.15C; the third current magnification is 0.50C; and the fourth current magnification is 0.80C.

9. The power battery system temperature control method according to claim 8, characterized in that: If the vehicle motion state is the driving state in S200, and if the thermal management unit does not normally respond to the cooling demand or heating demand of the BMS within 5 minutes after the cooling demand or heating demand is issued, the driving temperature averaging self-circulation control sub-process is executed; In S200, if the vehicle movement state is the charging state, and if the thermal management unit does not normally respond to the cooling demand or heating demand of the BMS within 5 minutes after the cooling demand or heating demand is issued, the charging temperature equalization self-circulation control sub-process is executed.

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