Battery charging and discharging system and control method thereof, vehicle and battery manager

Abstract

The invention discloses a battery charging and discharging system and a control method thereof, a vehicle and a battery manager, the battery charging and discharging system comprises a battery charging and discharging loop, one end of a positive electrode connecting line of the battery charging and discharging loop and one end of a negative electrode connecting line of the battery charging and discharging loop are connected to the positive end and the negative end of a power battery; the battery heating loop is bridged between the positive electrode connecting wire and the negative electrode connecting wire of the battery charging and discharging loop, and the battery heating loop comprises a thermistor unit used for heating the power battery; the battery manager is connected with the battery charging and discharging loop and the battery heating loop and is used for acquiring state parameters of the power battery and adjusting the heating temperature of the thermistor unit according to the state parameters of the power battery; by adopting the method, the heating power of the thermistor unit can be actively adjusted through the state parameters of the power battery, the heating efficiency is improved, and the heating time is shortened.

Description

Technical Field

[0001] The present invention relates to the technical field of power battery systems, and in particular to a battery charging and discharging system and a control method thereof, a vehicle and a battery manager. Background Art

[0002] In the related art, for a battery charging and discharging system, a thermistor unit and a pure resistance heating unit are set in series to heat the battery. When the temperature of the thermistor unit reaches its Curie point temperature, the resistance value of the thermistor unit will increase rapidly as the temperature rises, thereby preventing the risk of dry burning and achieving the purpose of passively protecting the battery charging and discharging system. However, when the resistance value of the thermistor unit increases rapidly as the temperature rises, it will also cause a decrease in heating power, affecting the heating efficiency. Summary of the invention

[0003] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, one object of the present invention is to provide a battery charging and discharging system, which can actively adjust the heating power of the thermistor unit according to the state parameters of the power battery, thereby improving the heating efficiency and shortening the heating time.

[0004] A second object of the present invention is to provide a vehicle.

[0005] A third objective of the present invention is to provide a control method for a battery charging and discharging system.

[0006] A fourth objective of the present invention is to provide a battery manager.

[0007] A fifth object of the present invention is to provide a computer-readable storage medium.

[0008] In order to solve the above problems, a first aspect of the present invention provides a battery charging and discharging system, including: a battery charging and discharging circuit, one end of the positive electrode connection line and one end of the negative electrode connection line of the battery charging and discharging circuit are connected to the positive and negative ends of the power battery; a battery heating circuit, the battery heating circuit is bridged between the positive electrode connection line and the negative electrode connection line of the battery charging and discharging circuit, and the battery heating circuit includes a thermistor unit for heating the power battery; a battery manager, the battery manager is connected to the battery charging and discharging circuit and the battery heating circuit, and is used to obtain the state parameters of the power battery and adjust the heating temperature of the thermistor unit according to the state parameters of the power battery.

[0009] According to the battery charging and discharging system of the embodiment of the present invention, the heating temperature of the thermistor unit is adjusted by the state parameters of the power battery, thereby adjusting the heating power of the battery charging and discharging system to the power battery during the heating process. Moreover, compared with the existing battery charging and discharging system in which the thermistor unit and the pure resistance heating unit are connected in series for heating, the battery charging and discharging system in the present application adjusts the heating power by the state parameters of the power battery, so that the battery charging and discharging system is no longer limited to the passive protection of the temperature of the thermistor unit reaching the Curie point temperature, thereby helping to improve the heating efficiency and shorten the heating time.

[0010] In some embodiments, the battery heating circuit also includes: a pure resistance heating unit, which is used to heat the power battery; a first contactor, which is connected in series with the thermistor unit; a second contactor, which is connected in series with the pure resistance heating unit and then connected in parallel with the first contactor; wherein the battery manager is connected to the first contactor and the second contactor, and the battery manager is specifically used to control the switching states of the first contactor and the second contactor according to the state parameters of the power battery to adjust the heating temperature of the thermistor unit.

[0011] In some embodiments, the battery charge and discharge circuit includes: a main positive contactor, a first end of the main positive contactor is connected to the positive terminal of the power battery and the thermistor unit, and a second end of the main positive contactor is used to connect to a rear-end load; a main negative contactor, a first end of the main negative contactor is connected to the negative terminal of the power battery, and a second end of the main negative contactor is connected to the first contactor, the second contactor, and the rear-end load.

[0012] In some embodiments, the battery charge and discharge circuit includes: a main positive contactor, a first end of the main positive contactor is connected to the positive terminal of the power battery, the first contactor, and the second contactor, and a second end of the main positive contactor is used to connect to a rear-end load; a main negative contactor, a first end of the main negative contactor is connected to the negative terminal of the power battery, and a second end of the main negative contactor is connected to the thermistor unit and the rear-end load.

[0013] In some embodiments, the battery manager is specifically used to: determine whether the state parameter of the power battery meets the charging or discharging heating condition, and control the second contactor to close.

[0014] In some embodiments, the state parameters of the power battery include at least the remaining power value of the power battery, the minimum temperature value and the maximum temperature value of the power battery during the charging and discharging process, and the battery manager is specifically used to: when the power battery is in a discharging state, determine that the remaining power value is greater than a first preset power value and the minimum temperature value is less than a first preset temperature and the maximum temperature value is less than a second preset temperature, and control the second contactor to close, wherein the second preset temperature is greater than the first preset temperature.

[0015] In some embodiments, the state parameters of the power battery include at least a minimum temperature value and a maximum temperature value of the power battery during the charging and discharging process, and the battery manager is specifically used to: when the power battery is in a charging state, determine that the minimum temperature value is less than a third preset temperature and the maximum temperature value is less than a fourth preset temperature, and control the second contactor to close, wherein the fourth preset temperature is greater than the third preset temperature.

[0016] In some embodiments, the thermistor unit is used to heat the surface of the power battery. After controlling the second contactor to close, the battery manager is specifically used to: determine whether the state parameters of the power battery meet the heating restriction conditions, and control the first contactor to be alternately closed and opened.

[0017] In some embodiments, the battery charging and discharging system also includes: a temperature detection device, which is connected to the battery manager and is used to detect the current heating temperature of the thermistor unit; the battery manager is specifically used to control the first contactor to be alternately closed and opened according to the current heating temperature when it is determined that the state parameters of the power battery meet the heating restriction conditions.

[0018] In some embodiments, the temperature detection device includes a plurality of temperature sensors.

[0019] In some embodiments, the temperature sensor is an NTC temperature sensor.

[0020] In some embodiments, the state parameters of the power battery include at least a minimum temperature value and a maximum temperature value of the power battery during the charging and discharging process, and the battery manager is specifically used to: calculate the temperature difference between the maximum temperature value and the minimum temperature value; when it is determined that the temperature difference is greater than a first preset temperature difference threshold, control the first contactor to be alternately closed and opened according to the current heating temperature.

[0021] In some embodiments, the battery manager is specifically used for: step a, determining the target temperature range of the temperature difference, and obtaining the target heating power according to the target temperature range; step b, controlling the first contactor to close; step c, determining the current resistance value of the thermal resistance heating unit according to the current heating temperature; step d, obtaining the total voltage value of the power battery, and obtaining the estimated heating power according to the total voltage value, the current resistance value and the resistance value of the pure resistance heating unit; step e, when it is determined that the estimated heating power reaches the target heating power, controlling the first contactor to disconnect; looping through step a, step b, step c, step d and step e until the state parameters of the power battery meet the heating exit conditions, controlling both the first contactor and the second contactor to disconnect.

[0022] In some embodiments, for step a, the battery manager is specifically used to: determine that the temperature difference is within a first target temperature range, and obtain a first target heating power based on the first target temperature range; determine that the temperature difference is within a second target temperature range, and obtain a second target heating power based on the second target temperature range; wherein the upper limit value of the first target temperature range is less than or equal to the lower limit value of the second target temperature range, and the first target heating power is greater than the second target heating power.

[0023] In some embodiments, the battery manager is also specifically used to: determine that the minimum temperature value is greater than a fifth preset temperature, and control the first contactor and the second contactor to be disconnected; or, determine that the maximum temperature value is greater than a sixth preset temperature, and control the first contactor and the second contactor to be disconnected; or, determine that the temperature difference is greater than a second preset temperature difference threshold, and control the first contactor and the second contactor to be disconnected.

[0024] In some embodiments, when the power battery is in a discharging state, the battery manager is further specifically used to: determine that the remaining power value of the power battery is less than a second preset power value, and control the first contactor and the second contactor to be disconnected.

[0025] A second aspect of the present invention provides a vehicle, comprising the battery charging and discharging system.

[0026] According to the vehicle of the embodiment of the present invention, through the battery charging and discharging system of the above embodiment, the heating power of the thermistor unit can be actively adjusted according to the state parameters of the power battery, which is beneficial to improving the heating efficiency and shortening the heating time.

[0027] A third aspect of the present invention provides a control method for a battery charging and discharging system, comprising: the battery charging and discharging system comprises a battery charging and discharging circuit and a battery heating circuit, the battery heating circuit is connected across the positive and negative poles of the battery charging and discharging circuit, the battery heating circuit comprises a thermistor unit for heating a power battery, and the control method comprises: obtaining a state parameter of the power battery; and adjusting a heating temperature of the thermistor unit according to the state parameter of the power battery.

[0028] According to the control method of the battery charging and discharging system of the embodiment of the present invention, the heating temperature of the thermistor unit is adjusted by the state parameters of the power battery, thereby adjusting the heating power of the battery charging and discharging system to the power battery during the heating process. Moreover, compared with the heating method in which the thermistor unit and the pure resistance heating unit are connected in series, the heating power is adjusted by the state parameters of the power battery in the present application, so that the battery charging and discharging system is no longer limited to the passive protection of the temperature of the thermistor unit reaching the Curie point temperature, thereby facilitating the improvement of heating efficiency and shortening the heating time.

[0029] In some embodiments, the battery heating circuit also includes a pure resistance heating unit, a first contactor and a second contactor for heating the power battery, the first contactor is connected in series with the thermistor unit, the second contactor is connected in series with the pure resistance heating unit and then connected in parallel with the first contactor, and the heating temperature of the thermistor unit is adjusted according to the state parameters of the power battery, including: controlling the switching states of the first contactor and the second contactor according to the state parameters of the power battery to adjust the heating temperature of the thermistor unit.

[0030] In some embodiments, the state parameters of the power battery control the switching states of the first contactor and the second contactor, including: determining that the state parameters of the power battery meet the charging or discharging heating conditions, and controlling the second contactor to close.

[0031] In some embodiments, the state parameters of the power battery include at least the remaining power value of the power battery, the minimum temperature value and the maximum temperature value of the power battery during the charging and discharging process, and determining that the state parameters of the power battery meet the charging or discharging heating conditions and controlling the second contactor to close include: when the power battery is in a discharging state, determining that the remaining power value is greater than a first preset power value and the minimum temperature value is less than a first preset temperature and the maximum temperature value is less than a second preset temperature, and controlling the second contactor to close, wherein the second preset temperature is greater than the first preset temperature.

[0032] In some embodiments, the state parameters of the power battery include at least a minimum temperature value and a maximum temperature value of the power battery during the charging and discharging process, and determining that the state parameters of the power battery meet the charging or discharging heating conditions and controlling the second contactor to close include: when the power battery is in a charging state, determining that the minimum temperature value is less than a third preset temperature and the maximum temperature value is less than a fourth preset temperature, and controlling the second contactor to close, wherein the fourth preset temperature is greater than the third preset temperature.

[0033] In some embodiments, the thermistor unit is used to heat the surface of the power battery. After controlling the second contactor to close, controlling the switching states of the first contactor and the second contactor according to the state parameters of the power battery, and also includes: determining that the state parameters of the power battery meet the heating restriction conditions, and controlling the first contactor to be alternately closed and opened.

[0034] In some embodiments, determining that the state parameters of the power battery meet the heating restriction conditions and controlling the first contactor to be alternately closed and opened include: obtaining the current heating temperature of the thermistor unit; and when determining that the state parameters of the power battery meet the heating restriction conditions, controlling the first contactor to be alternately closed and opened according to the current heating temperature.

[0035] In some embodiments, the state parameters of the power battery include at least a minimum temperature value and a maximum temperature value of the power battery during the charging and discharging process. When it is determined that the state parameters of the power battery meet the heating restriction conditions, the first contactor is controlled to be alternately closed and opened according to the current heating temperature, including: calculating the temperature difference between the maximum temperature value and the minimum temperature value; when it is determined that the temperature difference is greater than a first preset temperature difference threshold, the first contactor is controlled to be alternately closed and opened according to the current heating temperature.

[0036] In some embodiments, the first contactor is controlled to be alternately closed and opened according to the current heating temperature, including: step a, determining the target temperature range of the temperature difference, and obtaining the target heating power according to the target temperature range; step b, controlling the first contactor to close; step c, determining the current resistance value of the thermal resistance heating unit according to the current heating temperature; step d, obtaining the total voltage value of the power battery, and obtaining the estimated heating power according to the total voltage value, the current resistance value and the resistance value of the pure resistance heating unit; step e, when it is determined that the estimated heating power reaches the target heating power, controlling the first contactor to open; looping through steps a, b, c, d and e until the state parameters of the power battery meet the heating exit conditions, controlling both the first contactor and the second contactor to open.

[0037] In some embodiments, obtaining a target heating power according to the target temperature range includes: determining that the temperature difference is within a first target temperature range, and obtaining a first target heating power according to the first target temperature range; determining that the temperature difference is within a second target temperature range, and obtaining a second target heating power according to the second target temperature range; wherein the upper limit value of the first target temperature range is less than or equal to the lower limit value of the second target temperature range, and the first target heating power is greater than the second target heating power.

[0038] In some embodiments, after the state parameters of the power battery meet the heating exit conditions, the first contactor and the second contactor are controlled to be disconnected, including: determining that the minimum temperature value is greater than the fifth preset temperature, and controlling the first contactor and the second contactor to be disconnected; or, determining that the maximum temperature value is greater than the sixth preset temperature, and controlling the first contactor and the second contactor to be disconnected; or, determining that the temperature difference is greater than the second preset temperature difference threshold, and controlling the first contactor and the second contactor to be disconnected.

[0039] In some embodiments, when the power battery is in a discharging state, until the state parameter of the power battery meets the heating exit condition, the first contactor and the second contactor are controlled to be disconnected, and it also includes: determining that the remaining power value of the power battery is less than a second preset power value, and controlling the first contactor and the second contactor to be disconnected.

[0040] A fourth aspect of the present invention provides a battery manager, comprising: a processor; a memory connected to the processor in communication; the memory stores a computer program executable by the processor, and the processor implements the control method of the battery charging and discharging system when executing the computer program.

[0041] According to the battery manager of the embodiment of the present invention, the heating power of the thermistor unit can be actively adjusted according to the state parameters of the power battery, which is beneficial to improving the heating efficiency and shortening the heating time.

[0042] A fifth aspect of the present invention provides a computer-readable storage medium having a computer program stored thereon, and the computer program, when executed, implements the control method of the battery charging and discharging system.

[0043] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0045] Figure 1 is a schematic diagram of a battery charging and discharging system according to an embodiment of the present invention;

[0046] Figure 2 is a schematic diagram of a battery charging and discharging system according to another embodiment of the present invention;

[0047] Figure 3 is a structural block diagram of a vehicle according to an embodiment of the present invention;

[0048] Figure 4 is a flow chart of a control method of a battery charging and discharging system according to an embodiment of the present invention;

[0049] Figure 5 is a structural block diagram of a battery manager according to an embodiment of the present invention.

[0050] Reference numerals:

[0051] Vehicle 100;

[0052] Battery charging and discharging system 90;

[0053] Thermistor unit 1; pure resistance heating unit 2; first contactor 3; second contactor 4; power battery 5; battery manager 6; main negative contactor 7; main positive contactor 8; temperature detection device 9; rear end load 10; processor 61; memory 62. DETAILED DESCRIPTION

[0054] Embodiments of the present invention are described in detail below. The embodiments described with reference to the accompanying drawings are exemplary. Embodiments of the present invention are described in detail below.

[0055] In order to solve the above problems, a first embodiment of the present invention provides a battery charging and discharging system, which can actively adjust the heating power of the thermistor unit according to the state parameters of the power battery, thereby improving the heating efficiency and shortening the heating time.

[0056] Reference below Figure 1 A battery charging and discharging system 90 according to an embodiment of the present invention is described as follows: Figure 1 As shown, the system includes: a battery charging and discharging circuit, a battery heating circuit and a battery manager 6.

[0057] Among them, one end of the positive electrode connection line and one end of the negative electrode connection line of the battery charging and discharging circuit are connected to the positive and negative ends of the power battery 6; the battery heating circuit is connected between the positive electrode connection line and the negative electrode connection line of the battery charging and discharging circuit, and the battery heating circuit includes a thermistor unit 1 for heating the power battery; the battery manager 6 is connected to the battery charging and discharging circuit and the battery heating circuit, and is used to obtain the state parameters of the power battery, and adjust the heating temperature of the thermistor unit according to the state parameters of the power battery.

[0058] Specifically, the existing battery charging and discharging system heats the battery by setting a thermistor unit and a pure resistance heating unit in series. When the temperature of the thermistor unit reaches its Curie point, the resistance value of the thermistor unit will increase rapidly with the increase of temperature, thereby preventing the risk of dry burning and achieving the purpose of passively protecting the battery charging and discharging system. However, when the resistance value of the thermistor unit increases rapidly with the increase of temperature, it will also cause the heating power to decrease, affecting the heating efficiency. In order to solve this problem, the battery charging and discharging system in the present application obtains the state parameters of the power battery through the battery manager, and then adjusts the thermistor unit according to the state parameters of the power battery. The heating temperature of the thermistor unit is adjusted by adjusting the heating temperature of the thermistor unit according to the state parameters of the power battery, thereby changing the resistance value of the thermistor unit, and then adjusting the heating power of the power battery to the battery charging and discharging system during the heating process. Compared with the heating method in which the thermistor unit is connected in series with the pure resistance heating unit, the battery charging and discharging system in the present application adjusts the heating power according to the state parameters of the power battery, so that the battery charging and discharging system is no longer limited to the passive protection of the temperature of the thermistor unit reaching the Curie point temperature, thereby helping to improve the heating efficiency and shorten the heating time.

[0059] According to the battery charging and discharging system 90 of the embodiment of the present invention, the heating temperature of the thermistor unit is adjusted by the state parameters of the power battery, thereby adjusting the heating power of the battery charging and discharging system to the power battery during the heating process. Moreover, compared with the existing battery charging and discharging system in which the thermistor unit and the pure resistance heating unit are connected in series for heating, the battery charging and discharging system in the present application adjusts the heating power by the state parameters of the power battery, which means that the battery charging and discharging system is no longer limited to the passive protection of the temperature of the thermistor unit reaching the Curie point temperature, thereby helping to improve the heating efficiency and shorten the heating time.

[0060] In some embodiments, Figure 1 As shown, the battery heating circuit further includes: a pure resistance heating unit 2 , a first contactor 3 and a second contactor 4 .

[0061] Among them, the pure resistance heating unit 2 is used to heat the power battery; the first contactor 3 is connected in series with the thermistor unit 1; the second contactor 4 is connected in series with the pure resistance heating unit 2 and then connected in parallel with the first contactor 3; the battery manager 6 is connected to the first contactor 3 and the second contactor 4, and the battery manager 6 is specifically used to control the switching state of the first contactor and the second contactor according to the state parameters of the power battery to adjust the heating temperature of the thermistor unit.

[0062] Specifically, the switch states of the first contactor and the second contactor are controlled to be closed or open according to the state parameters of the power battery, so that the thermistor unit works alone or the thermistor unit and the pure resistance heating unit work together, and the characteristic of the thermistor unit that the resistance value changes with the temperature is used to adjust the heating temperature of the thermistor unit, thereby changing the resistance value of the thermistor unit, and then adjusting the heating power of the power battery by the battery charging and discharging system during the heating process. Compared with the heating method in which the thermistor unit and the pure resistance heating unit are connected in series, the circuit connection method based on the thermistor unit and the pure resistance heating unit in the present application adjusts the heating power through the state parameters of the power battery, so that the battery charging and discharging system will no longer be limited to the passive protection of the temperature of the thermistor unit reaching the Curie point temperature, thereby helping to improve the heating efficiency, shorten the heating time, and the regulation of the heating power is more accurate.

[0063] In some embodiments, as shown in FIG. 1 , the battery charging and discharging circuit includes: a main positive contactor 8 and a main negative contactor 7 .

[0064] Among them, Figure 1As shown, the first end of the main positive contactor 8 is connected to the positive terminal of the power battery 5 and the thermistor unit 1, and the second end of the main positive contactor 8 is used to connect the rear-end load; the first end of the main negative contactor 7 is connected to the negative terminal of the power battery 5, and the second end of the main negative contactor 7 is connected to the first contactor 3, the second contactor 4, and the rear-end load 10. That is to say, after the high voltage is applied to the vehicle, when the power battery is in a discharging state, the main positive contactor 8 and the main negative contactor 7 are controlled to be closed so that the power battery 5 supplies power to the rear-end load 10; combined with the signal interaction between the vehicle end and the charging pile end, when the power battery is in a charging state, the main positive contactor 8 and the main negative contactor 7 are closed.

[0065] In some embodiments, Figure 2 As shown, the battery charging and discharging circuit includes: a main positive contactor 8 and a main negative contactor 7.

[0066] Among them, Figure 2 As shown, the first end of the main positive contactor 8 is connected to the positive terminal of the power battery 5, the first contactor 3, and the second contactor 4, and the second end of the main positive contactor 8 is used to connect the rear-end load 10; the first end of the main negative contactor 7 is connected to the negative terminal of the power battery 5, and the second end of the main negative contactor 7 is connected to the thermistor unit 1 and the rear-end load 10. That is to say, after the high voltage is applied to the vehicle, when the power battery is in a discharging state, the main positive contactor 8 and the main negative contactor 7 are controlled to be closed so that the power battery 5 supplies power to the rear-end load 10; combined with the signal interaction between the vehicle end and the charging pile end, when the power battery is in a charging state, the main positive contactor 8 and the main negative contactor 7 are closed.

[0067] In an embodiment, when the first contactor or the second contactor has a fault such as adhesion, the negative contactor serves as a redundancy to improve the safety of the battery charging and discharging system.

[0068] In some embodiments, the battery manager is specifically used to: determine whether the state parameters of the power battery meet the charging or discharging heating conditions, and control the second contactor to close. That is, the battery manager detects the state parameters of the power battery and determines whether the state parameters meet the charging or discharging heating conditions, thereby determining whether to control the thermistor unit and the pure resistance heating unit to heat the power battery during the charging and discharging process of the power battery. If the state parameters meet the charging or discharging heating conditions, the second contactor is controlled to close, so that the thermistor unit and the pure resistance heating unit jointly heat the power battery.

[0069] In some embodiments, the state parameters of the power battery include at least the remaining power value of the power battery, the minimum temperature value and the maximum temperature value of the power battery during the charging and discharging process, and the battery manager is specifically used to: when the power battery is in a discharging state, determine that the remaining power value is greater than a first preset power value and the minimum temperature value is less than a first preset temperature and the maximum temperature value is less than a second preset temperature, and control the second contactor to close, wherein the second preset temperature is greater than the first preset temperature.

[0070] The first preset temperature may be understood as a temperature value set according to the minimum temperature of the power battery in the discharge state that affects the performance of the power battery, such as the first preset temperature is 5°C, which is not limited. The second preset temperature may be understood as a temperature value set according to the maximum temperature of the power battery in the discharge state that affects the performance of the power battery, such as the second preset temperature is 30°C, which is not limited.

[0071] Specifically, when the power battery is in a discharging state, the battery manager collects the remaining power value of the power battery and the minimum temperature value and the maximum temperature value of the power battery during the discharging process, and determines whether the remaining power value, the minimum temperature value and the maximum temperature value meet the discharge heating condition, so as to determine whether the power battery controls the thermistor unit and the pure resistance heating unit to heat the power battery during the discharging process. If it is determined that the remaining power value is greater than the first preset power value, and the first preset power value may be 10%, it means that the remaining power can provide the current for the thermistor unit and the pure resistance heating unit to work during the discharging process of the power battery, and the remaining power can meet the discharge demand of the power battery, and the minimum temperature value is less than the first preset temperature and the maximum temperature value is less than the second preset temperature, it means that the overall temperature of the power battery is relatively low during the discharging process. At this time, the power battery needs to be heated to ensure the discharge performance of the power battery under low temperature. After the above-mentioned discharge heating condition is met, the second contactor is controlled to be closed so that the thermistor unit and the pure resistance heating unit jointly heat the power battery, thereby increasing the overall temperature of the power battery. In addition, if the minimum temperature value, the maximum temperature value and the remaining power value do not meet the discharge heating condition, it is determined that the power battery is not heated during the discharging process. Therefore, in the present application, the heating temperature of the thermistor unit is actively adjusted through the state parameters of the power battery, so that the battery charging and discharging system is no longer limited to the passive protection of the temperature of the thermistor unit reaching the Curie point temperature, thereby helping to improve the heating efficiency and shorten the heating time.

[0072] In some embodiments, the state parameters of the power battery include at least the minimum temperature value and the maximum temperature value of the power battery during the charging and discharging process, and the battery manager is specifically used to: when the power battery is in a charging state, determine that the minimum temperature value is less than a third preset temperature and the maximum temperature value is less than a fourth preset temperature, and control the second contactor to close, wherein the fourth preset temperature is greater than the third preset temperature.

[0073] The third preset temperature may be understood as a temperature value set according to the fact that the minimum temperature of the power battery in the charging state affects the performance of the power battery, such as the third preset temperature is 0°C, which is not limited. The fourth preset temperature may be understood as a temperature value set according to the fact that the maximum temperature of the power battery in the charging state affects the performance of the power battery, such as the fourth preset temperature is 15°C, which is not limited.

[0074] Specifically, when the power battery is in a charging state, the battery manager collects the minimum temperature value and the maximum temperature value of the power battery during the charging process, and determines whether the minimum temperature value and the maximum temperature value meet the charging heating condition, so as to determine whether the power battery controls the thermistor unit and the pure resistance heating unit to heat the power battery during the charging process, that is, if it is determined that the minimum temperature value is less than the third preset temperature and the maximum temperature value is less than the fourth preset temperature, it means that the overall temperature of the power battery is low during the charging process. At this time, the power battery needs to be heated to ensure the charging performance of the power battery under low temperature conditions. After the above charging heating conditions are met, the second contactor is controlled to close so that the thermistor unit and the pure resistance heating unit jointly heat the power battery, thereby increasing the overall temperature of the power battery. In addition, if the minimum temperature value and the maximum temperature value do not meet the charging heating condition, it is determined that the power battery is not heated during the charging process. Therefore, in the present application, the heating temperature of the thermistor unit is actively adjusted through the state parameters of the power battery, so that the battery charging and discharging system will no longer be limited to the passive protection of the temperature of the thermistor unit reaching the Curie point temperature, thereby helping to improve the heating efficiency and shorten the heating time.

[0075] In some embodiments, the thermistor unit is used to heat the surface of the power battery. After controlling the second contactor to close, the battery manager is specifically used to: determine whether the state parameters of the power battery meet the heating restriction conditions, and control the first contactor to be alternately closed and opened.

[0076] Specifically, the thermistor unit in the present application is arranged on the surface of the power battery and close to the external environment, and the heat transfer rate of the power battery surface is relatively fast, so that the surface temperature of the power battery close to the external environment is easier to reduce, and the pure resistance heating unit is arranged inside the power battery, and because the internal insulation effect of the power battery is better, that is, due to the stacking and structural layout of the battery cells, after controlling the second contactor to close, so that the thermistor unit and the pure resistance heating unit jointly heat the power battery, the temperature of the power battery close to the external environment surface rises slowly and the internal temperature of the power battery rises rapidly, which leads to excessive temperature difference of the power battery. Based on this, in order to ensure the safety of the power battery during the charging and discharging heating process, and to avoid excessive temperature difference As for the problem affecting the performance of the power battery, the present application pre-sets the heating restriction condition for limiting the thermistor unit and the pure resistance heating unit to heat the power battery, that is, during the process of the thermistor unit and the pure resistance heating unit heating the power battery, if the state parameter of the power battery meets the heating restriction condition, it means that the temperature difference of the power battery is too large at this time, and then the first contactor is controlled to be alternately closed and disconnected. When the first contactor is controlled to be closed, the heating power of the thermistor unit to the power battery during the heating process is increased, so that the surface temperature of the power battery close to the external environment is rapidly increased, thereby reducing the temperature difference, ensuring the safety of the power battery during the charging and discharging heating process, and avoiding the problem of affecting the performance of the power battery due to the excessive temperature difference. When the first contactor is controlled to be disconnected, the second contactor is in a closed state, and the thermistor unit and the pure resistance heating unit heat the power battery, thereby increasing the surface temperature while increasing the overall temperature of the power battery, and increasing the heating rate of the overall temperature of the power battery.

[0077] In some embodiments, Figure 1 and Figure 2 As shown, the battery charging and discharging system 90 further includes: a temperature detection device 9 .

[0078] Among them, the temperature detection device 9 is connected to the battery manager 6 for detecting the current heating temperature of the thermistor unit 1; the battery manager 6 is specifically used to control the first contactor to be alternately closed and opened according to the current heating temperature when it is determined that the state parameters of the power battery meet the heating restriction conditions.

[0079] Specifically, during the heating process of the power battery by the thermistor unit and the pure resistance heating unit under charge and discharge heating, the current heating temperature of the thermistor unit is detected in real time. Since the thermistor unit has the characteristic that the resistance value changes with temperature, the heating temperature of the thermistor unit is adjusted to change the resistance value of the thermistor unit, thereby adjusting the heating power of the thermistor unit to the power battery during the heating process, and then changing the surface temperature of the power battery. When it is determined that the state parameter of the power battery meets the heating restriction condition, it means that the temperature difference of the power battery is too large at this time, and then the first contactor is controlled to be alternately closed and opened by the current heating temperature, that is, the time of alternating closing and opening of the first contactor is controlled by the current heating temperature, thereby changing the heating temperature of the thermistor unit, and then adjusting the heating power of the thermistor unit to the power battery during the heating process, so that the temperature difference can be reduced to a normal range under the heating power without affecting the performance of the power battery.

[0080] In some embodiments, the temperature detection device includes multiple temperature sensors, that is, multiple temperature sensors are set in the thermistor unit to collect the current heating temperature of the thermistor unit, so as to more accurately determine the current heating temperature of the thermistor unit.

[0081] In some embodiments, the temperature sensor is a Negative Temperature Coefficient Sensor (NTC) temperature sensor.

[0082] In some embodiments, the state parameter of the power battery includes at least the minimum temperature value and the maximum temperature value of the power battery during the charging and discharging process, and the battery manager is specifically used to: calculate the temperature difference between the maximum temperature value and the minimum temperature value; when it is determined that the temperature difference is greater than the first preset temperature difference threshold, control the first contactor to be alternately closed and disconnected according to the current heating temperature. That is to say, in the process of heating the power battery by the thermistor unit and the pure resistance heating unit under charging and discharging heating, the temperature difference between the maximum temperature value of the power battery during the charging and discharging process and the minimum temperature value of the power battery during the charging and discharging process is calculated, and the power battery continuously determines whether the temperature difference is greater than the preset temperature difference threshold during the charging and discharging heating process. If it is determined that the temperature difference is greater than the first preset temperature difference threshold, it means that the temperature difference of the power battery is too large and affects its performance or the safety of the power battery. Then, according to the current heating temperature, the first contactor is controlled to be alternately closed and disconnected, so that the surface temperature of the power battery close to the external environment is increased, thereby reducing the temperature difference to a normal range. Therefore, in the present application, the temperature difference is adjusted by the state parameter, so as to ensure the safety of the power battery during the charging and discharging heating process, and avoid the problem of affecting the performance of the power battery due to the excessive temperature difference. In addition, compared with the method of heating the battery by separately setting up a pure resistance heating unit or a thermistor unit, the battery temperature difference during the heating process can be effectively controlled, the consistency can be improved, and the battery life can be extended.

[0083] In some embodiments, the battery manager is specifically configured to:

[0084] Step a, determining the target temperature range where the temperature difference is located, and obtaining the target heating power according to the target temperature range. In other words, multiple temperature ranges are divided and the heating power is set accordingly. If the target temperature range where the temperature difference is located is determined and the corresponding target heating power is called, the temperature difference can be reduced to a normal range under the target heating power without affecting the performance of the power battery.

[0085] Step b, controlling the first contactor to close so that the thermistor heating unit heats the power battery, thereby quickly increasing the surface temperature of the power battery to reduce the temperature difference and be lower than the first preset temperature difference threshold, thereby ensuring the safety of the power battery during the charging and discharging heating process, and avoiding the problem of affecting the performance of the power battery due to excessive temperature difference.

[0086] Step c, determining the current resistance value of the thermal resistance heating unit according to the current heating temperature.

[0087] It should be noted that, since the thermistor unit has the characteristic that the resistance value changes with temperature, the current resistance value of the thermistor heating unit corresponding to the current heating temperature of the thermistor unit can be obtained through the curve corresponding to the heating temperature and resistance value of the thermistor unit.

[0088] Step d, obtaining the total voltage value of the power battery, and obtaining the estimated heating power according to the total voltage value, the current resistance value and the resistance value of the pure resistance heating unit, wherein the estimated heating power is the heating power of the thermistor unit to the power battery at the current heating temperature.

[0089] Step e: when it is determined that the estimated heating power reaches the target heating power, the first contactor is controlled to be disconnected. In the process of the thermistor heating unit heating the power battery, the estimated heating power changes with the increase of the current heating temperature of the thermistor heating unit. When the estimated heating power reaches the target heating power, it means that the surface temperature of the power battery is increased at this time, so that the temperature difference is reduced to a normal range and no longer affects the performance of the power battery.

[0090] Step a, step b, step c, step d and step e are executed in a loop until the state parameters of the power battery meet the heating exit condition. At this time, it means that the temperature of the power battery is high and there is no need to heat the power battery to improve the charging and discharging performance. Then, the first contactor and the second contactor are controlled to be disconnected so that the thermistor unit and the pure resistance heating unit stop heating the power battery.

[0091] In some embodiments, for step a, the battery manager is specifically used to: if it is determined that the temperature difference is within the first target temperature range, then call the first target heating power corresponding to the first target temperature range, and then control the first contactor to close, so that the thermosensitive heating unit heats the power battery, and when the estimated heating power reaches the first target heating power, control the first contactor to disconnect; if it is determined that the temperature difference is within the second target temperature range, then call the second target heating power corresponding to the second target temperature range, control the first contactor to close, so that the thermosensitive heating unit heats the power battery, and when the estimated heating power reaches the second target heating power, control the first contactor to disconnect; wherein, the upper limit value of the first target temperature range is less than or equal to the lower limit value of the second target temperature range, and the first target heating power is greater than the second target heating power.

[0092] In some embodiments, the battery manager is further specifically used to: if it is determined that the minimum temperature value is greater than the fifth preset temperature, it means that the temperature of the power battery is high and there is no need to heat the power battery to improve the charging and discharging performance, then the first contactor and the second contactor are controlled to be disconnected, thereby controlling the thermistor unit and the pure resistance heating unit to stop heating the power battery; or, if it is determined that the maximum temperature value is greater than the sixth preset temperature, it means that the temperature of the power battery is high and there is no need to heat the power battery to improve the charging and discharging performance, then the first contactor and the second contactor are controlled to be disconnected, thereby controlling the thermistor unit and the pure resistance heating unit to stop heating the power battery; or, if it is determined that the temperature difference value is greater than the second preset temperature difference threshold value, the temperature difference value is too large, then the first contactor and the second contactor are controlled to be disconnected, thereby controlling the thermistor unit and the pure resistance heating unit to stop heating the power battery. Thus, the thermistor unit and the pure resistance heating unit are controlled to stop heating the power battery by the minimum temperature value, the maximum temperature value and the temperature difference.

[0093] In some embodiments, when the power battery is in a discharging state, the battery manager is further specifically used to: when it is determined that the remaining power value of the power battery is less than a second preset power value, it means that the remaining power cannot provide the current required for the thermistor unit and the pure resistance heating unit of the power battery to work during the discharge process, and the remaining power cannot meet the discharge requirements of the power battery, and the first contactor and the second contactor are controlled to be disconnected, thereby controlling the thermistor unit and the pure resistance heating unit to stop heating the power battery.

[0094] A second aspect of the present invention provides a vehicle 100, such as Figure 3 As shown, it includes the battery charging and discharging system 90 in the above embodiment.

[0095] According to the vehicle 100 of the embodiment of the present invention, through the battery charging and discharging system of the above embodiment, the heating power of the thermistor unit can be actively adjusted according to the state parameters of the power battery, which is beneficial to improving the heating efficiency and shortening the heating time.

[0096] A third aspect of the present invention provides a control method for a battery charging and discharging system, wherein the battery charging and discharging system includes a battery charging and discharging circuit and a battery heating circuit, wherein the battery heating circuit is connected across the positive and negative electrode connections of the battery charging and discharging circuit, and the battery heating circuit includes a thermistor unit for heating the power battery, such as Figure 4 As shown, the control method at least includes: step S1 to step S2.

[0097] Step S1, the battery manager obtains status parameters of the power battery.

[0098] Step S2, adjusting the heating temperature of the thermistor unit according to the state parameters of the power battery.

[0099] Specifically, the existing battery charging and discharging system heats the battery by setting a thermistor unit and a pure resistance heating unit in series. When the temperature of the thermistor unit reaches its Curie point temperature, the resistance value of the thermistor unit will increase rapidly with the increase of temperature, thereby preventing the risk of dry burning and achieving the purpose of passively protecting the battery charging and discharging system. However, when the resistance value of the thermistor unit increases rapidly with the increase of temperature, it will also cause the heating power to decrease, affecting the heating efficiency. In order to solve this problem, the heating temperature of the thermistor unit is adjusted by the state parameters of the power battery in the present application, that is, the thermistor unit has a resistance According to the characteristic that the value changes with temperature, the heating temperature of the thermistor unit is adjusted by the state parameters of the power battery, thereby changing the resistance value of the thermistor unit, and then adjusting the heating power of the power battery to the battery charging and discharging system during the heating process. Compared with the heating method in which the thermistor unit is connected in series with the pure resistance heating unit, the circuit connection method based on the thermistor unit and the pure resistance heating unit in the present application adjusts the heating power by the state parameters of the power battery, so that the battery charging and discharging system will no longer be limited to the passive protection of the temperature of the thermistor unit reaching the Curie point temperature, thereby helping to improve the heating efficiency and shorten the heating time.

[0100] Exemplarily, when the thermistor unit is a positive temperature coefficient thermistor unit, the thermistor unit is arranged on the surface of the power battery and close to the external environment. When it is identified through the state parameters of the power battery that the surface temperature of the power battery is high, the heating temperature of the thermistor unit is adjusted according to the state parameters of the power battery. That is, in the process of the thermistor unit heating the power battery, the heating temperature of the thermistor unit increases so that the resistance value of the thermistor unit increases, thereby reducing the heating power of the battery charging and discharging system on the power battery during the heating process and preventing the risk of dry burning.

[0101] According to the control method of the battery charging and discharging system of the embodiment of the present invention, the heating temperature of the thermistor unit is adjusted by the state parameters of the power battery, thereby adjusting the heating power of the battery charging and discharging system to the power battery during the heating process. Moreover, compared with the heating method in which the thermistor unit and the pure resistance heating unit are connected in series, the heating power is adjusted by the state parameters of the power battery in the present application, so that the battery charging and discharging system is no longer limited to the passive protection of the temperature of the thermistor unit reaching the Curie point temperature, thereby facilitating the improvement of heating efficiency and shortening the heating time.

[0102] In some embodiments, the battery heating circuit also includes a pure resistance heating unit for heating the power battery, a first contactor and a second contactor, the first contactor is connected in series with the thermistor unit, the second contactor is connected in series with the pure resistance heating unit and then connected in parallel with the first contactor, and the heating temperature of the thermistor unit is adjusted according to the state parameters of the power battery, including: controlling the switching states of the first contactor and the second contactor according to the state parameters of the power battery to adjust the heating temperature of the thermistor unit.

[0103] Specifically, the switch states of the first contactor and the second contactor are controlled to be closed or open according to the state parameters of the power battery, so that the thermistor unit works alone or the thermistor unit and the pure resistance heating unit work together, and the characteristic of the thermistor unit that the resistance value changes with the temperature is used to adjust the heating temperature of the thermistor unit, thereby changing the resistance value of the thermistor unit, and then adjusting the heating power of the power battery by the battery charging and discharging system during the heating process. Compared with the heating method in which the thermistor unit and the pure resistance heating unit are connected in series, the circuit connection method based on the thermistor unit and the pure resistance heating unit in the present application adjusts the heating power through the state parameters of the power battery, so that the battery charging and discharging system is no longer limited to the passive protection of the temperature of the thermistor unit reaching the Curie point temperature, thereby helping to improve the heating efficiency, shorten the heating time, and the regulation of the power battery heating power is more accurate.

[0104] Exemplarily, when the thermistor unit is a positive temperature coefficient thermistor unit, the thermistor unit is arranged on the surface of the power battery and close to the external environment, and the pure resistance heating unit is arranged inside the power battery, the state parameter of the power battery may be the temperature information of the power battery. When it is identified through the state parameter of the power battery that the surface temperature of the power battery is low and the internal temperature of the power battery is high, the switch state of the first contactor is controlled to be closed, and the switch state of the second contactor is controlled to be open, so that the thermistor unit heats the surface of the power battery alone. At this time, the resistance value of the thermistor is small, thereby improving the heating effect of the battery charging and discharging system on the power battery during the heating process. Thermal power, thereby quickly increasing the surface temperature of the power battery; or when the power battery status parameters identify that the overall temperature of the power battery is low, the switch state of the second contactor is controlled to be closed, so that the pure resistance heating unit and the thermistor unit heat the power battery together, thereby increasing the overall temperature of the power battery; or when the power battery status parameters identify that the overall temperature of the power battery is low and the surface temperature of the power battery is very low, the switch states of the first contactor and the second contactor are controlled to be closed, thereby increasing the heating power of the thermistor unit to the power battery during the heating process, thereby increasing the surface temperature while increasing the overall temperature of the power battery.

[0105] In some embodiments, controlling the switch states of the first contactor and the second contactor according to the state parameters of the power battery includes: determining that the state parameters of the power battery meet the charging or discharging heating conditions, and controlling the second contactor to close. That is, the battery manager detects the state parameters of the power battery, and determines whether the state parameters meet the charging or discharging heating conditions, thereby determining whether the power battery controls the thermistor unit and the pure resistance heating unit to heat the power battery during the charging and discharging process. If the state parameters meet the charging or discharging heating conditions, the second contactor is controlled to close, so that the thermistor unit and the pure resistance heating unit jointly heat the power battery.

[0106] In some embodiments, the state parameters of the power battery include at least the remaining power value of the power battery, the minimum temperature value and the maximum temperature value of the power battery during the charging and discharging process, and determining that the state parameters of the power battery meet the charging or discharging heating conditions and controlling the second contactor to close include: when the power battery is in a discharging state, determining that the remaining power value is greater than a first preset power value and the minimum temperature value is less than a first preset temperature and the maximum temperature value is less than a second preset temperature, and controlling the second contactor to close, wherein the second preset temperature is greater than the first preset temperature.

[0107] Specifically, when the power battery is in a discharging state, the battery manager collects the remaining power value of the power battery and the minimum temperature value and the maximum temperature value of the power battery during the discharging process, and determines whether the remaining power value, the minimum temperature value and the maximum temperature value meet the discharge heating condition, so as to determine whether the power battery controls the thermistor unit and the pure resistance heating unit to heat the power battery during the discharging process. If it is determined that the remaining power value is greater than the first preset power value, and the first preset power value may be 10%, it means that the remaining power can provide the current for the thermistor unit and the pure resistance heating unit to work during the discharging process of the power battery, and the remaining power can meet the discharge demand of the power battery, and the minimum temperature value is less than the first preset temperature and the maximum temperature value is less than the second preset temperature, it means that the overall temperature of the power battery is relatively low during the discharging process. At this time, the power battery needs to be heated to ensure the discharge performance of the power battery under low temperature. After the above-mentioned discharge heating condition is met, the second contactor is controlled to be closed so that the thermistor unit and the pure resistance heating unit jointly heat the power battery, thereby increasing the overall temperature of the power battery. In addition, if the minimum temperature value, the maximum temperature value and the remaining power value do not meet the discharge heating condition, it is determined that the power battery is not heated during the discharging process. Therefore, in the present application, the heating temperature of the thermistor unit is actively adjusted through the state parameters of the power battery, so that the battery charging and discharging system is no longer limited to the passive protection of the temperature of the thermistor unit reaching the Curie point temperature, thereby helping to improve the heating efficiency and shorten the heating time.

[0108] In some embodiments, the state parameters of the power battery include at least the minimum temperature value and the maximum temperature value of the power battery during the charging and discharging process, and determining that the state parameters of the power battery meet the charging or discharging heating conditions and controlling the second contactor to close include: when the power battery is in a charging state, determining that the minimum temperature value is less than a third preset temperature and the maximum temperature value is less than a fourth preset temperature, and controlling the second contactor to close, wherein the fourth preset temperature is greater than the third preset temperature.

[0109] Specifically, when the power battery is in a charging state, the battery manager collects the minimum temperature value and the maximum temperature value of the power battery during the charging process, and determines whether the minimum temperature value and the maximum temperature value meet the charging heating condition, so as to determine whether the power battery controls the thermistor unit and the pure resistance heating unit to heat the power battery during the charging process, that is, if it is determined that the minimum temperature value is less than the third preset temperature and the maximum temperature value is less than the fourth preset temperature, it means that the overall temperature of the power battery is low during the charging process. At this time, the power battery needs to be heated to ensure the charging performance of the power battery under low temperature conditions. After the above charging heating conditions are met, the second contactor is controlled to close so that the thermistor unit and the pure resistance heating unit jointly heat the power battery, thereby increasing the overall temperature of the power battery. In addition, if the minimum temperature value and the maximum temperature value do not meet the charging heating condition, it is determined that the power battery is not heated during the charging process. Therefore, in the present application, the heating temperature of the thermistor unit is actively adjusted through the state parameters of the power battery, so that the battery charging and discharging system will no longer be limited to the passive protection of the temperature of the thermistor unit reaching the Curie point temperature, thereby helping to improve the heating efficiency and shorten the heating time.

[0110] In some embodiments, the thermistor unit is used to heat the surface of the power battery. After controlling the second contactor to close, the switching states of the first contactor and the second contactor are controlled according to the state parameters of the power battery. It also includes: determining that the state parameters of the power battery meet the heating restriction conditions, and controlling the first contactor to be alternately closed and opened.

[0111] Specifically, the thermistor unit in the present application is arranged on the surface of the power battery and close to the external environment, and the heat transfer rate of the power battery surface is relatively fast, so that the surface temperature of the power battery close to the external environment is easier to reduce, and the pure resistance heating unit is arranged inside the power battery, and because the internal insulation effect of the power battery is better, that is, due to the stacking and structural layout of the battery cells, after controlling the second contactor to close, so that the thermistor unit and the pure resistance heating unit jointly heat the power battery, the temperature of the power battery close to the external environment surface rises slowly and the internal temperature of the power battery rises rapidly, which leads to excessive temperature difference of the power battery. Based on this, in order to ensure the safety of the power battery during the charging and discharging heating process, and to avoid excessive temperature difference As for the problem affecting the performance of the power battery, the present application pre-sets the heating restriction condition for limiting the thermistor unit and the pure resistance heating unit to heat the power battery, that is, during the process of the thermistor unit and the pure resistance heating unit heating the power battery, if the state parameter of the power battery meets the heating restriction condition, it means that the temperature difference of the power battery is too large at this time, and then the first contactor is controlled to be alternately closed and disconnected. When the first contactor is controlled to be closed, the heating power of the thermistor unit to the power battery during the heating process is increased, so that the surface temperature of the power battery close to the external environment is rapidly increased, thereby reducing the temperature difference, ensuring the safety of the power battery during the charging and discharging heating process, and avoiding the problem of affecting the performance of the power battery due to the excessive temperature difference. When the first contactor is controlled to be disconnected, the second contactor is in a closed state, and the thermistor unit and the pure resistance heating unit heat the power battery, thereby increasing the surface temperature while increasing the overall temperature of the power battery, and increasing the heating rate of the overall temperature of the power battery.

[0112] In some embodiments, determining that the state parameters of the power battery meet the heating restriction conditions and controlling the first contactor to be alternately closed and opened include: obtaining the current heating temperature of the thermistor unit; when determining that the state parameters of the power battery meet the heating restriction conditions, controlling the first contactor to be alternately closed and opened according to the current heating temperature.

[0113] Specifically, during the heating process of the power battery by the thermistor unit and the pure resistance heating unit under charge and discharge heating, the current heating temperature of the thermistor unit is detected in real time. Since the thermistor unit has the characteristic that the resistance value changes with temperature, the heating temperature of the thermistor unit is adjusted to change the resistance value of the thermistor unit, thereby adjusting the heating power of the thermistor unit to the power battery during the heating process, and then changing the surface temperature of the power battery. When it is determined that the state parameter of the power battery meets the heating restriction condition, it means that the temperature difference of the power battery is too large at this time, and then the first contactor is controlled to be alternately closed and opened by the current heating temperature, that is, the time of alternating closing and opening of the first contactor is controlled by the current heating temperature, thereby changing the heating temperature of the thermistor unit, and then adjusting the heating power of the thermistor unit to the power battery during the heating process, so that the temperature difference can be reduced to a normal range under the heating power without affecting the performance of the power battery.

[0114] Exemplarily, when the thermistor unit is a positive temperature coefficient thermistor unit, the lower the current heating temperature of the thermistor unit, the smaller the resistance value of the thermistor unit. Based on this, when it is determined that the state parameters of the power battery meet the heating restriction conditions, it means that the temperature difference of the power battery is too large at this time, and the first contactor is controlled to be alternately closed and opened by the current heating temperature, that is, the time of alternating closing and opening of the first contactor is controlled by the current heating temperature, so as to increase the heating temperature of the thermistor unit when controlling the first contactor to close, and then increase the heating power of the thermistor unit to the power battery during the heating process, so as to increase the surface temperature of the power battery, so that the temperature difference can be reduced to a normal range under the heating power without affecting the performance of the power battery.

[0115] In some embodiments, the state parameter of the power battery includes at least the minimum temperature value and the maximum temperature value of the power battery during the charging and discharging process. When it is determined that the state parameter of the power battery meets the heating restriction condition, the first contactor is controlled to be alternately closed and disconnected according to the current heating temperature, including: calculating the temperature difference between the maximum temperature value and the minimum temperature value; when it is determined that the temperature difference is greater than the first preset temperature difference threshold, the first contactor is controlled to be alternately closed and disconnected according to the current heating temperature. That is to say, during the heating process of the power battery by the thermistor unit and the pure resistance heating unit under charging and discharging heating, the temperature difference between the maximum temperature value of the power battery during the charging and discharging process and the minimum temperature value of the power battery during the charging and discharging process is calculated, and the power battery continuously determines whether the temperature difference is greater than the preset temperature difference threshold during the charging and discharging heating process. If it is determined that the temperature difference is greater than the first preset temperature difference threshold, it means that the temperature difference of the power battery is too large and affects its performance or the safety of the power battery. Then, the first contactor is controlled to be alternately closed and disconnected according to the current heating temperature, so that the surface temperature of the power battery close to the external environment is increased, thereby reducing the temperature difference to a normal range. Therefore, in this application, the temperature difference is adjusted by the state parameter to ensure the safety of the power battery during the charging and discharging heating process, and avoid the problem of affecting the performance of the power battery due to excessive temperature difference. In addition, compared with the method of heating the battery by separately setting a pure resistance heating unit or a thermistor unit, the battery temperature difference during the heating process can be effectively controlled, the consistency can be improved, and the battery life can be extended.

[0116] In some embodiments, controlling the first contactor to alternately close and open according to the current heating temperature includes:

[0117] Step a, determining the target temperature range where the temperature difference is located, and obtaining the target heating power according to the target temperature range. In other words, multiple temperature ranges are divided and the heating power is set accordingly. If the target temperature range where the temperature difference is located is determined and the corresponding target heating power is called, the temperature difference can be reduced to a normal range under the target heating power without affecting the performance of the power battery.

[0118] Step b, controlling the first contactor to close so that the thermistor heating unit heats the power battery, thereby quickly increasing the surface temperature of the power battery to reduce the temperature difference and be lower than the first preset temperature difference threshold, thereby ensuring the safety of the power battery during the charging and discharging heating process, and avoiding the problem of affecting the performance of the power battery due to excessive temperature difference.

[0119] Step c, determining the current resistance value of the thermal resistance heating unit according to the current heating temperature.

[0120] In step d, the battery manager obtains the total voltage value of the power battery, and obtains the estimated heating power according to the total voltage value, the current resistance value and the resistance value of the pure resistance heating unit.

[0121] Step e: when it is determined that the estimated heating power reaches the target heating power, the first contactor is controlled to be disconnected. In the process of the thermistor heating unit heating the power battery, the estimated heating power changes with the increase of the current heating temperature of the thermistor heating unit. When the estimated heating power reaches the target heating power, it means that the surface temperature of the power battery is increased at this time, so that the temperature difference is reduced to a normal range and no longer affects the performance of the power battery.

[0122] Step a, step b, step c, step d and step e are executed in a loop until the state parameters of the power battery meet the heating exit condition. At this time, it means that the temperature of the power battery is high and there is no need to heat the power battery to improve the charging and discharging performance. Then, the first contactor and the second contactor are controlled to be disconnected so that the thermistor unit and the pure resistance heating unit stop heating the power battery.

[0123] In some embodiments, a target heating power is obtained according to a target temperature range. If it is determined that the temperature difference is within a first target temperature range, the first target heating power corresponding to the first target temperature range is called, and then the first contactor is controlled to be closed, so that the thermistor heating unit heats the power battery. When the estimated heating power reaches the first target heating power, the first contactor is controlled to be disconnected. If it is determined that the temperature difference is within a second target temperature range, the second target heating power corresponding to the second target temperature range is called, and the first contactor is controlled to be closed, so that the thermistor heating unit heats the power battery. When the estimated heating power reaches the second target heating power, the first contactor is controlled to be disconnected. wherein, the upper limit value of the first target temperature range is less than or equal to the lower limit value of the second target temperature range, and the first target heating power is greater than the second target heating power.

[0124] In some embodiments, until the state parameters of the power battery meet the heating exit conditions, the first contactor and the second contactor are controlled to be disconnected, including: determining that the minimum temperature value is greater than the fifth preset temperature, controlling the first contactor and the second contactor are both disconnected; or, determining that the maximum temperature value is greater than the sixth preset temperature, controlling the first contactor and the second contactor are both disconnected; or, determining that the temperature difference is greater than the second preset temperature difference threshold, controlling the first contactor and the second contactor are both disconnected.

[0125] In some embodiments, until the state parameter of the power battery meets the heating exit condition, the first contactor and the second contactor are controlled to be disconnected, that is, the minimum temperature value is determined to be greater than the fifth preset temperature, which means that the temperature of the power battery is high and there is no need to heat the power battery to improve the charging and discharging performance, then the first contactor and the second contactor are controlled to be disconnected, thereby controlling the thermistor unit and the pure resistance heating unit to stop heating the power battery; or, if the maximum temperature value is determined to be greater than the sixth preset temperature, then it means that the temperature of the power battery is high and there is no need to heat the power battery to improve the charging and discharging performance, then the first contactor and the second contactor are controlled to be disconnected, thereby controlling the thermistor unit and the pure resistance heating unit to stop heating the power battery; or, if the temperature difference is determined to be greater than the second preset temperature difference threshold, the temperature difference is too large, then the first contactor and the second contactor are controlled to be disconnected, thereby controlling the thermistor unit and the pure resistance heating unit to stop heating the power battery. Thus, the thermistor unit and the pure resistance heating unit are controlled to stop heating the power battery by the minimum temperature value, the maximum temperature value and the temperature difference.

[0126] The fifth preset temperature can be understood as a temperature value set according to the minimum temperature of the power battery no longer affecting its performance, such as the fifth preset temperature can be 15 degrees Celsius, and there is no limitation on the comparison. The sixth preset temperature can be understood as a temperature value set according to the maximum temperature of the power battery no longer affecting its performance, such as the sixth preset temperature is 40 degrees Celsius, and there is no limitation on the comparison.

[0127] In some embodiments, when the power battery is in a discharging state, until the state parameter of the power battery meets the heating exit condition, the first contactor and the second contactor are controlled to be disconnected, and the method further includes: determining that the remaining power value of the power battery is less than the second preset power value, and controlling the first contactor and the second contactor to be disconnected, that is, when it is determined that the remaining power value of the power battery is less than the second preset power value, it means that the remaining power cannot provide the current required for the thermistor unit and the pure resistance heating unit to work during the discharge process of the power battery, and the remaining power cannot meet the discharge demand of the power battery, then the first contactor and the second contactor are controlled to be disconnected, so as to control the thermistor unit and the pure resistance heating unit to stop heating the power battery. Therefore, the thermistor unit and the pure resistance heating unit can also be controlled to stop heating the power battery according to the size of the remaining power value.

[0128] A fourth aspect of the present invention provides a battery manager 6, such as Figure 5 As shown, the battery manager 6 includes: a processor 61 and a memory 62 which is communicatively connected to the processor 61 .

[0129] The memory 62 stores a computer program that can be executed by the processor 61 , and the processor 61 implements the control method of the battery charging and discharging system of the above embodiment when executing the computer program.

[0130] It should be noted that the specific implementation of the battery manager 6 in the embodiment of the present invention is similar to the specific implementation of the control method of the battery charging and discharging system in any of the above embodiments of the present invention. Please refer to the description of the method part for details. In order to reduce redundancy, it will not be repeated here.

[0131] According to the battery manager 6 of the embodiment of the present invention, the heating power of the thermistor unit can be actively adjusted according to the state parameters of the power battery, which is beneficial to improving the heating efficiency and shortening the heating time.

[0132] A fifth aspect of the present invention provides a computer storage medium having a computer program stored thereon, wherein the computer program is executed by a processor to implement the control method of the battery charging and discharging system of the above embodiment.

[0133] In the description of this specification, any process or method description in a flowchart or otherwise described herein may be understood to represent a module, fragment or portion of code including one or more executable instructions for implementing the steps of a custom logical function or process, and the scope of the preferred embodiments of the present invention includes alternative implementations in which functions may not be performed in the order shown or discussed, including performing functions in a substantially simultaneous manner or in reverse order depending on the functions involved, which should be understood by technicians in the technical field to which the embodiments of the present invention belong.

[0134] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as an ordered list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by an instruction execution system, device or apparatus (such as a computer-based system, a system including a processor, or other system that can fetch instructions from an instruction execution system, device or apparatus and execute instructions), or in combination with these instruction execution systems, devices or apparatuses. For the purpose of this specification, "computer-readable medium" can be any device that can contain, store, communicate, propagate or transmit a program for use by an instruction execution system, device or apparatus, or in combination with these instruction execution systems, devices or apparatuses. More specific examples of computer-readable media (a non-exhaustive list) include the following: an electrical connection with one or more wires (electronic device), a portable computer disk box (magnetic device), a random access memory (RAM), a read-only memory (ROM), an erasable and programmable read-only memory (EPROM or flash memory), a fiber optic device, and a portable compact disk read-only memory (CDROM). In addition, the computer-readable medium may even be paper or other suitable medium on which the program is printed, since the program may be obtained electronically, for example, by optically scanning the paper or other medium and then editing, interpreting or processing in other suitable ways if necessary, and then stored in a computer memory.

[0135] It should be understood that the various parts of the present invention can be implemented by hardware, software, firmware or a combination thereof. In the above-mentioned embodiments, a plurality of steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented by hardware, as in another embodiment, it can be implemented by any one of the following technologies known in the art or their combination: a discrete logic circuit having a logic gate circuit for implementing a logic function for a data signal, a dedicated integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0136] A person skilled in the art may understand that all or part of the steps in the method for implementing the above-mentioned embodiment may be completed by instructing related hardware through a program, and the program may be stored in a computer-readable storage medium, which, when executed, includes one or a combination of the steps of the method embodiment.

[0137] In addition, each functional unit in each embodiment of the present invention may be integrated into a processing module, or each unit may exist physically separately, or two or more units may be integrated into one module. The above-mentioned integrated module may be implemented in the form of hardware or in the form of a software functional module. If the integrated module is implemented in the form of a software functional module and sold or used as an independent product, it may also be stored in a computer-readable storage medium.

[0138] The storage medium mentioned above may be a read-only memory, a magnetic disk or an optical disk, etc. Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limiting the present invention. A person of ordinary skill in the art may change, modify, replace and modify the above embodiments within the scope of the present invention.

[0139] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example.

[0140] Although the embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

Claims

1. A battery charging and discharging system, characterized in that: include: A battery charge and discharge circuit, wherein one end of the positive electrode connection line and one end of the negative electrode connection line of the battery charge and discharge circuit are connected to the positive and negative ends of the power battery; A battery heating circuit, the battery heating circuit is connected across the positive electrode connection line and the negative electrode connection line of the battery charging and discharging circuit, and the battery heating circuit includes a thermistor unit for heating the power battery; A battery manager is connected to the battery charging and discharging circuit and the battery heating circuit, and is used to obtain the state parameters of the power battery and adjust the heating temperature of the thermistor unit according to the state parameters of the power battery.

2. The battery charging and discharging system according to claim 1, characterized in that: The battery heating circuit also includes: A pure resistance heating unit, wherein the pure resistance heating unit is used to heat the power battery; a first contactor, the first contactor being connected in series with the thermistor unit; a second contactor, the second contactor being connected in series with the pure resistance heating unit and then connected in parallel with the first contactor; The battery manager is connected to the first contactor and the second contactor, and is specifically used to control the switching states of the first contactor and the second contactor according to the state parameters of the power battery to adjust the heating temperature of the thermistor unit.

3. The battery charging and discharging system according to claim 2, characterized in that: The battery charging and discharging circuit comprises: A main positive contactor, wherein a first end of the main positive contactor is connected to the positive terminal of the power battery and the thermistor unit, and a second end of the main positive contactor is used to connect to a rear end load; A main negative contactor, wherein a first end of the main negative contactor is connected to the negative terminal of the power battery, and a second end of the main negative contactor is connected to the first contactor, the second contactor, and the rear-end load.

4. The battery charging and discharging system according to claim 2, characterized in that: The battery charging and discharging circuit comprises: A main positive contactor, wherein a first end of the main positive contactor is connected to the positive terminal of the power battery, the first contactor, and the second contactor, and a second end of the main positive contactor is used to connect to a rear-end load; A main negative contactor, wherein a first end of the main negative contactor is connected to the negative terminal of the power battery, and a second end of the main negative contactor is connected to the thermistor unit and the rear-end load.

5. The battery charging and discharging system according to any one of claims 2 to 4, characterized in that: The battery manager is specifically used for: It is determined that the state parameter of the power battery meets the charging or discharging heating condition, and the second contactor is controlled to close.

6. The battery charging and discharging system according to claim 5, characterized in that: The state parameters of the power battery include at least the remaining power value of the power battery, the minimum temperature value and the maximum temperature value of the power battery during the charging and discharging process, and the battery manager is specifically used for: When the power battery is in a discharging state, it is determined that the remaining power value is greater than a first preset power value, the minimum temperature value is less than a first preset temperature, and the maximum temperature value is less than a second preset temperature, and the second contactor is controlled to close, wherein the second preset temperature is greater than the first preset temperature.

7. The battery charging and discharging system according to claim 5, characterized in that: The state parameter of the power battery includes at least a minimum temperature value and a maximum temperature value of the power battery during the charging and discharging process. The battery manager is specifically used for: When the power battery is in a charging state, it is determined that the minimum temperature value is less than a third preset temperature and the maximum temperature value is less than a fourth preset temperature, and the second contactor is controlled to be closed, wherein the fourth preset temperature is greater than the third preset temperature.

8. The battery charging and discharging system according to claim 5, characterized in that: The thermistor unit is used to heat the surface of the power battery. After controlling the second contactor to close, the battery manager is specifically used to: It is determined that the state parameter of the power battery meets the heating restriction condition, and the first contactor is controlled to be alternately closed and opened.

9. The battery charging and discharging system according to claim 8, characterized in that: The battery charging and discharging system further comprises: a temperature detection device, the temperature detection device being connected to the battery manager and being used to detect the current heating temperature of the thermistor unit; The battery manager is specifically configured to control the first contactor to be alternately closed and opened according to the current heating temperature when it is determined that the state parameter of the power battery meets the heating restriction condition.

10. The battery charging and discharging system according to claim 9, characterized in that: The temperature detection device includes a plurality of temperature sensors.

11. The battery charging and discharging system according to claim 10, characterized in that: The temperature sensor is an NTC temperature sensor.

12. The battery charging and discharging system according to any one of claims 9 to 11, characterized in that: The state parameter of the power battery includes at least a minimum temperature value and a maximum temperature value of the power battery during the charging and discharging process. The battery manager is specifically used for: Calculating a temperature difference between the maximum temperature value and the minimum temperature value; When it is determined that the temperature difference is greater than a first preset temperature difference threshold, the first contactor is controlled to be alternately closed and opened according to the current heating temperature.

13. The battery charging and discharging system according to claim 12, characterized in that: The battery manager is specifically used for: Step a, determining a target temperature range in which the temperature difference is located, and obtaining a target heating power according to the target temperature range; Step b, controlling the first contactor to close; Step c, determining the current resistance value of the thermal resistance heating unit according to the current heating temperature; Step d, obtaining a total voltage value of the power battery, and obtaining an estimated heating power according to the total voltage value, the current resistance value and the resistance value of the pure resistance heating unit; Step e, when it is determined that the estimated heating power reaches the target heating power, controlling the first contactor to disconnect; The step a, the step b, the step c, the step d and the step e are executed in a loop until the state parameter of the power battery meets the heating exit condition, and the first contactor and the second contactor are controlled to be disconnected.

14. The battery charging and discharging system according to claim 13, characterized in that: For step a, the battery manager is specifically used for: Determining that the temperature difference is within a first target temperature range, and obtaining a first target heating power according to the first target temperature range; Determining that the temperature difference is within a second target temperature range, and obtaining a second target heating power according to the second target temperature range; The upper limit of the first target temperature range is less than or equal to the lower limit of the second target temperature range, and the first target heating power is greater than the second target heating power.

15. The battery charging and discharging system according to claim 13 or 14, characterized in that: The battery manager is also specifically used for: Determining that the minimum temperature value is greater than a fifth preset temperature, and controlling both the first contactor and the second contactor to be disconnected; Alternatively, it is determined that the maximum temperature value is greater than a sixth preset temperature, and the first contactor and the second contactor are both controlled to be disconnected; Alternatively, it is determined that the temperature difference is greater than a second preset temperature difference threshold, and the first contactor and the second contactor are both controlled to be disconnected.

16. The battery charging and discharging system according to claim 15, characterized in that: When the power battery is in a discharging state, the battery manager is further specifically used for: It is determined that the remaining power value of the power battery is less than a second preset power value, and the first contactor and the second contactor are controlled to be disconnected.

17. A vehicle, characterized in that: A battery charging and discharging system comprising any one of claims 1-16.

18. A control method for a battery charging and discharging system, characterized in that: The battery charging and discharging system includes a battery charging and discharging circuit and a battery heating circuit, the battery heating circuit is connected across the positive and negative electrode connections of the battery charging and discharging circuit, the battery heating circuit includes a thermistor unit for heating the power battery, and the control method includes: Acquiring state parameters of the power battery; The heating temperature of the thermistor unit is adjusted according to the state parameter of the power battery.

19. The control method of the battery charging and discharging system according to claim 18, characterized in that: The battery heating circuit further includes a pure resistance heating unit, a first contactor, and a second contactor for heating the power battery, wherein the first contactor is connected in series with the thermistor unit, and the second contactor is connected in series with the pure resistance heating unit and then connected in parallel with the first contactor, and the heating temperature of the thermistor unit is adjusted according to the state parameter of the power battery, including: The switching states of the first contactor and the second contactor are controlled according to the state parameters of the power battery to adjust the heating temperature of the thermistor unit.

20. The control method of the battery charging and discharging system according to claim 19, characterized in that: Controlling the switching states of the first contactor and the second contactor according to the state parameter of the power battery includes: It is determined that the state parameter of the power battery meets the charging or discharging heating condition, and the second contactor is controlled to close.

21. The control method of the battery charging and discharging system according to claim 20, characterized in that: The state parameters of the power battery at least include a remaining power value of the power battery, a minimum temperature value and a maximum temperature value of the power battery during the charging and discharging process, and determining that the state parameters of the power battery meet the charging or discharging heating condition, and controlling the second contactor to close, including: When the power battery is in a discharging state, it is determined that the remaining power value is greater than a first preset power value, the minimum temperature value is less than a first preset temperature, and the maximum temperature value is less than a second preset temperature, and the second contactor is controlled to close, wherein the second preset temperature is greater than the first preset temperature.

22. The control method of the battery charging and discharging system according to claim 20, characterized in that: The state parameter of the power battery includes at least a minimum temperature value and a maximum temperature value of the power battery during the charging and discharging process, and determining that the state parameter of the power battery meets the charging or discharging heating condition, and controlling the second contactor to close, comprises: When the power battery is in a charging state, it is determined that the minimum temperature value is less than a third preset temperature and the maximum temperature value is less than a fourth preset temperature, and the second contactor is controlled to be closed, wherein the fourth preset temperature is greater than the third preset temperature.

23. The control method of the battery charging and discharging system according to claim 20, characterized in that: The thermistor unit is used to heat the surface of the power battery, and after controlling the second contactor to close, the switching states of the first contactor and the second contactor are controlled according to the state parameters of the power battery, and further includes: It is determined that the state parameter of the power battery meets the heating restriction condition, and the first contactor is controlled to be alternately closed and opened.

24. The control method of the battery charging and discharging system according to claim 23, characterized in that: Determining that the state parameter of the power battery meets the heating restriction condition, and controlling the first contactor to be alternately closed and opened, comprises: Obtaining the current heating temperature of the thermistor unit; When it is determined that the state parameter of the power battery meets the heating restriction condition, the first contactor is controlled to be alternately closed and opened according to the current heating temperature.

25. The control method of the battery charging and discharging system according to claim 24, characterized in that: The state parameter of the power battery at least includes a minimum temperature value and a maximum temperature value of the power battery during the charging and discharging process. When it is determined that the state parameter of the power battery meets the heating restriction condition, the first contactor is controlled to be alternately closed and opened according to the current heating temperature, including: Calculating a temperature difference between the maximum temperature value and the minimum temperature value; When it is determined that the temperature difference is greater than a first preset temperature difference threshold, the first contactor is controlled to be alternately closed and opened according to the current heating temperature.

26. The control method of the battery charging and discharging system according to claim 25, characterized in that: Controlling the first contactor to be alternately closed and opened according to the current heating temperature includes: Step a, determining a target temperature range in which the temperature difference is located, and obtaining a target heating power according to the target temperature range; Step b, controlling the first contactor to close; Step c, determining the current resistance value of the thermal resistance heating unit according to the current heating temperature; Step d, obtaining a total voltage value of the power battery, and obtaining an estimated heating power according to the total voltage value, the current resistance value and the resistance value of the pure resistance heating unit; Step e, when it is determined that the estimated heating power reaches the target heating power, controlling the first contactor to disconnect; The step a, the step b, the step c, the step d and the step e are executed in a loop until the state parameter of the power battery meets the heating exit condition, and the first contactor and the second contactor are controlled to be disconnected.

27. The control method of the battery charging and discharging system according to claim 26, characterized in that: Obtaining a target heating power according to the target temperature range includes: Determining that the temperature difference is within a first target temperature range, and obtaining a first target heating power according to the first target temperature range; Determining that the temperature difference is within a second target temperature range, and obtaining a second target heating power according to the second target temperature range; The upper limit of the first target temperature range is less than or equal to the lower limit of the second target temperature range, and the first target heating power is greater than the second target heating power.

28. The control method of the battery charging and discharging system according to claim 26 or 27, characterized in that: After the state parameter of the power battery meets the heating exit condition, the first contactor and the second contactor are controlled to be disconnected, including: Determining that the minimum temperature value is greater than a fifth preset temperature, and controlling both the first contactor and the second contactor to be disconnected; Alternatively, it is determined that the maximum temperature value is greater than a sixth preset temperature, and the first contactor and the second contactor are both controlled to be disconnected; Alternatively, it is determined that the temperature difference is greater than a second preset temperature difference threshold, and the first contactor and the second contactor are both controlled to be disconnected.

29. The control method of the battery charging and discharging system according to claim 28, characterized in that: When the power battery is in a discharging state, until the state parameter of the power battery meets the heating exit condition, the first contactor and the second contactor are controlled to be disconnected, and further comprising: It is determined that the remaining power value of the power battery is less than a second preset power value, and the first contactor and the second contactor are controlled to be disconnected.

30. A battery manager, characterized in that: include: processor; a memory communicatively coupled to the processor; The memory stores a computer program that can be executed by the processor, and when the processor executes the computer program, the control method of the battery charging and discharging system according to any one of claims 18 to 29 is implemented.

31. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed, the control method of the battery charging and discharging system according to any one of claims 18 to 29 is implemented.

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