Heating control method, energy storage system and readable storage medium

Abstract

The application discloses a heating control method, an energy storage system and a readable storage medium. The heating control method comprises the following steps: when it is determined that heating is to be performed, the direction of the current loop of the voltage conversion circuit is controlled to be kept as the direction of discharging the battery cell module; the current temperature of the heating module is obtained, and the target heating power of the heating module is determined according to the current temperature of the heating module; the target heating power is obtained by the energy storage inverter, and the input voltage of the heating module is adjusted according to the target heating power, so as to adjust the heating power of the heating module. In the foregoing manner, the battery pack can be quickly heated at low temperature, so that the battery pack can be normally used, and the safety risk caused by abnormal reaction at low temperature can be avoided, thereby prolonging the service life of the battery pack.

Description

TECHNICAL FIELD

[0001] Embodiments of the present application relate to the technical field of heating control, in particular to a heating control method, an energy storage system and a readable storage medium. BACKGROUND

[0002] The current mainstream distributed energy storage system has one or more battery packs. In some application scenarios, the temperature of the battery pack can be relatively low, such as tens of degrees below zero. In this case, directly enabling the battery pack can easily cause performance to drop, safety hazards, shortened service life, and other negative effects. SUMMARY

[0003] Embodiments of the present application provide a heating control method, an energy storage system and a readable storage medium, which can ensure that the battery pack is quickly heated at low temperature, so as to ensure that the battery pack can be normally used, and the safety risk caused by abnormal low temperature reaction can be avoided, thereby making the battery pack have a longer service life.

[0004] In a first aspect, embodiments of the present application provide a heating control method applied to an energy storage system, the energy storage system including N battery packs, N heating modules and an energy storage inverter, the battery packs and the heating modules corresponding one by one, the N battery packs being in communication connection with the energy storage inverter, the battery pack including a cell module and a voltage conversion circuit, the voltage conversion circuit being in electrical connection with the cell module, the energy storage inverter and the heating module respectively, the cell module including at least one cell, wherein N is a positive integer, and the method includes: when the battery pack determines to be heated, controlling the direction of a current loop of the voltage conversion circuit to be kept in a direction of discharging the cell module; the battery pack acquiring a current temperature of the heating module and determining a target heating power of the heating module according to the current temperature of the heating module; the energy storage inverter acquiring the target heating power and adjusting an input voltage of the heating module according to the target heating power to adjust the heating power of the heating module.

[0005] In one or more embodiments, the step of the battery pack acquiring the current temperature of the heating module and determining the target heating power of the heating module according to the current temperature of the heating module includes: the battery pack determining the target heating power based on the minimum value between the maximum heating power supported by the heating module and a first target power, wherein the first target power is a heating power that can be reached based on the real-time temperature of the heating module.

[0006] In one or more embodiments, the first target power Pac is: Pac=Pmax-(T-T1) / (T2-T1)*Pmax, wherein Pmax is the maximum heating power, T is the current temperature, T1 is the lowest working temperature to maintain the heating demand, and T2 is the upper limit value of the temperature of the heating module.

[0007] In one or more embodiments, the step of adjusting the input voltage of the heating module according to the target heating power by the energy storage inverter comprises: determining, by the energy storage inverter, a target input voltage of the heating module based on the target heating power; increasing, by the energy storage inverter, the input voltage of the heating module to increase the heating power of the heating module when the current input voltage of the heating module is less than the target input voltage.

[0008] In one or more embodiments, the voltage conversion circuit comprises a bus capacitor electrically connected to the heating module, and a voltage on the bus capacitor is the input voltage of the heating module; the step of determining, by the energy storage inverter, the target input voltage of the heating module based on the target heating power comprises: determining, by the energy storage inverter, a first target voltage based on an arithmetic square root of a product of the target heating power and a resistance value of the heating module; and determining, by the energy storage inverter, the target input voltage based on a minimum value between the first target voltage and an upper limit value of the input voltage of the heating module, wherein the upper limit value of the input voltage of the heating module is a minimum value between a maximum voltage that the bus capacitor can withstand and a maximum voltage that the heating module can withstand.

[0009] In one or more embodiments, the energy storage system further comprises an energy control module and a switch module, the switch module is electrically connected between the N battery packs and the energy storage inverter, the energy control module is electrically connected to the switch module to control the switch module to establish or break the electrical connection between the N battery packs and the energy storage inverter, and the energy control module is in communication connection with the energy storage inverter; the method further comprises: maintaining, by the energy storage inverter, the power output by the energy storage inverter unchanged when it is determined that the actual heating power of the heating module is greater than or equal to the maximum heating power supported by the heating module, and / or when it is determined that the input voltage of the heating module is greater than or equal to the upper limit value of the input voltage of the heating module; outputting, by the energy storage inverter, a first signal to the energy control module to make the energy control module control the switch module to break the electrical connection between the N battery packs and the energy storage inverter when it is determined that the actual temperature of the heating module is greater than or equal to the upper limit value of the temperature of the heating module.

[0010] In one or more embodiments, after the step of outputting, by the energy storage inverter, the first signal to the energy control module is performed, the method further comprises: outputting, by the energy storage inverter, a second signal to the energy control module to make the energy control module control the switch module to establish the electrical connection between the N battery packs and the energy storage inverter when it is determined that the current temperature of the heating module is less than the minimum operating temperature for maintaining the heating demand.

[0011] In one or more embodiments, the voltage conversion circuit includes a first inductor, a second inductor, a first bridge arm and a second bridge arm, the first inductor is electrically connected between the positive electrode of the battery cell module and a first node of the first bridge arm, the first node being a connection point between an upper bridge arm and a lower bridge arm of the first bridge arm, the second inductor is electrically connected between the positive electrode of the battery cell module and a second node of the second bridge arm, the second node being a connection point between an upper bridge arm and a lower bridge arm of the second bridge arm, the first bridge arm and the second bridge arm are connected in parallel with a bus capacitor in the voltage conversion circuit; the step of the battery pack controlling the direction of the current loop of the voltage conversion circuit to remain in the direction of discharging the battery cell module includes: the battery pack controls the upper bridge arms of the first bridge arm and the second bridge arm to remain off, and controls the lower bridge arms of the first bridge arm and the second bridge arm to alternately conduct and turn off, so as to control the direction of the current loop of the voltage conversion circuit to remain in the direction of discharging the battery cell module.

[0012] In a second aspect, the embodiments of the present application provide an energy storage system, including N battery packs, N heating modules and an energy storage inverter, wherein N is a positive integer; the battery packs correspond to the heating modules one by one, the N battery packs are in communication connection with the energy storage inverter, the battery pack includes a battery cell module and a voltage conversion circuit, the voltage conversion circuit is electrically connected with the battery cell module, the energy storage inverter and the heating module respectively, and the battery cell module includes at least one battery cell; wherein the battery pack is used to execute the method steps executed by the battery pack in the heating control method in the first aspect, and the energy storage inverter is used to execute the method steps executed by the energy storage inverter in the heating control method in the first aspect.

[0013] In a third aspect, the embodiments of the present application provide a computer readable storage medium, which stores a computer program, when the computer program is executed, the heating control method in the first aspect is realized.

[0014] The beneficial effects of the present application are: the heating control method of the embodiment of the present application is applied to an energy storage system, the energy storage system includes N battery packs, N heating modules and an energy storage inverter, the battery pack and the heating module are one-to-one corresponding, the N battery packs are in communication connection with the energy storage inverter, the battery pack includes a battery cell module and a voltage conversion circuit, the voltage conversion circuit is electrically connected with the battery cell module, the energy storage inverter and the heating module respectively, and the battery cell module includes at least one battery cell. The heating control method includes that when the battery pack determines to heat, the direction of the current loop of the voltage conversion circuit is kept as the discharging direction of the battery cell module, so as to ensure that the battery pack will not be charged, thereby ensuring that the input voltage of the heating module can be raised. Secondly, the heating control method further includes that the battery pack acquires the current temperature of the heating module, and determines the target heating power of the heating module according to the current temperature of the heating module; the energy storage inverter acquires the target heating power, and adjusts the input voltage of the heating module according to the target heating power, so as to adjust the heating power of the heating module. Therefore, the battery pack can be heated when the temperature is low, which is beneficial to avoid the safety risk caused by abnormal reaction at low temperature, so that the battery pack has a longer service life, and the heating power of the heating module is also raised to realize rapid heating, so as to ensure that the battery pack can be normally used. BRIEF DESCRIPTION OF DRAWINGS

[0015] One or more embodiments are illustrated by way of example in the figures that are part of this document and which illustrate key / representative principles of the one or more embodiments. The embodiments are not limited to the examples given herein.

[0016] Figure 1 is a schematic diagram of an energy storage system provided by an embodiment of the present application Figure 1 ;

[0017] Figure 2 is a schematic diagram of the connection of an energy storage inverter, a first heating module and a first battery pack provided by an embodiment of the present application

[0018] Figure 3 is a circuit structure schematic diagram of a voltage conversion circuit provided by an embodiment of the present application

[0019] Figure 4 is a schematic diagram of an energy storage system provided by an embodiment of the present application Figure 2 ;

[0020] Figure 5 is a flowchart of a heating control method provided by an embodiment of the present application Figure 1 ;

[0021] Figure 6 is a flowchart of a heating control method provided by an embodiment of the present application Figure 2 ;

[0022] Figure 7is a flow of the heating control method provided by the embodiment of the present application Figure 3 ;

[0023] Figure 8 is a flow of the heating control method provided by the embodiment of the present application Figure 4 ;

[0024] Figure 9 is a flow of the heating control method provided by the embodiment of the present application Figure 5 ;

[0025] Figure 10 is a flow of the heating control method provided by the embodiment of the present application Figure 6 . DETAILED DESCRIPTION

[0026] In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and in detail below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are some but not all of the embodiments of the present application. It should be understood that the specific embodiments described herein are only used to explain the present application and should not be used to limit the present application.

[0027] It should be noted that when an element is described as being "connected" to another element, it can be directly connected to the other element or one or more intermediate elements can be present therebetween.

[0028] In addition, the technical features involved in each of the embodiments of the present application described below can be combined with each other as long as they do not conflict with each other.

[0029] Please refer to Figure 1 , Figure 1 is a schematic diagram of a composition block diagram of the energy storage system provided by the embodiment of the present application. As shown in Figure 1 , the energy storage system 100 includes N battery packs, N heating modules and an energy storage inverter 10. The N battery packs include a first battery pack BA1, a second battery pack BA2,..., and an Nth battery pack BAN, and the N heating modules include a first heating module H1, a second heating module H2,..., and an Nth heating module HN, where N is a positive integer.

[0030] The battery pack and the heating module correspond to each other. Specifically, each battery pack is electrically connected to the corresponding heating module to supply power thereto, for example, the first battery pack BA1 is electrically connected to the first heating module H1 to supply power to the first heating module H1; each heating module heats the corresponding battery pack, for example, the first heating module H1 heats the first battery pack BA1.

[0031] The energy storage inverter 10 is connected with N battery packs and N heating modules. The connection between the N battery packs and the energy storage inverter 10 includes electrical connection and communication connection. Based on the electrical connection, the N battery packs and the energy storage inverter 10 can realize power transmission, that is, the energy storage inverter 10 charges the battery pack or the battery pack discharges to the energy storage inverter 10; based on the communication connection, the energy storage inverter 10 can monitor and manage the state of each battery pack in real time, for example, the energy storage inverter 10 can obtain the voltage, current, temperature, SOC (state of charge), SOH (state of health), fault alarm and other information of each battery pack, and the energy storage inverter 10 can also send control commands such as charge and discharge enable, power instruction, charge and discharge cutoff condition to the battery pack according to the system demand and the battery state. The connection between the energy storage inverter 10 and the N heating modules is electrical connection, and the energy storage inverter 10 can adjust the input voltage of the heating module to adjust the heating power of the heating module. Among them, each battery pack can execute the method steps executed by the battery pack in the heating control method of any embodiment of the present application, and the energy storage inverter 10 can execute the method steps executed by the energy storage inverter 10 in the heating control method of any embodiment of the present application.

[0032] In some embodiments, each heating module is configured as an electric heating film, wherein the electric heating film is a flexible or rigid thin film heating element that converts electrical energy into heat energy.

[0033] Figure 2 A schematic diagram showing that the energy storage inverter 10 is connected with the first heating module H1 and the first battery pack BA1 is shown. It can be understood that the connection mode and working principle of the energy storage inverter 10 with other heating modules except the first heating module H1 and other battery packs except the first battery pack BA1 are the same as Figure 2 The connection mode and working principle of the energy storage inverter 10 with the first heating module H1 and the first battery pack BA1 are the same as shown.

[0034] As shown in Figure 2 The first battery pack BA1 includes a battery cell module BA11 and a voltage conversion circuit BA12. The voltage conversion circuit BA12 is electrically connected with the battery cell module BA11, the energy storage inverter 10 and the first heating module H1 respectively. Among them, the battery cell module BA11 includes at least one battery cell for storing and providing electrical energy. When the battery cell module BA11 includes a plurality of battery cells, the plurality of battery cells are connected in parallel, series or mixed connection, and the mixed connection includes series connection and parallel connection. The voltage conversion circuit BA12 is configured to output the voltage output by the battery cell module BA11 after boosting or bucking, or charge the battery cell module BA11 after boosting or bucking the voltage output by the energy storage inverter 10.

[0035] Figure 3 An exemplary circuit structure of the voltage conversion circuit BA12 is shown. As Figure 3As shown, the voltage conversion circuit BA12 includes a first inductor L1, a second inductor L2, a first bridge arm BA121, a second bridge arm BA122, and a bus capacitor C1.

[0036] The first inductor L1 is electrically connected between the positive electrode of the battery cell module BA11 and a first node P1 of the first bridge arm BA121. The first node P1 is a connection point between an upper bridge arm and a lower bridge arm of the first bridge arm BA121, the upper bridge arm of the first bridge arm BA121 includes a first switch Q1, the lower bridge arm of the first bridge arm BA121 includes a second switch Q2, and the first node P1 is a connection point between the first switch Q1 and the second switch Q2. The second inductor L2 is electrically connected between the positive electrode of the battery cell module BA11 and a second node P2 of the second bridge arm BA121. The second node P2 is a connection point between an upper bridge arm and a lower bridge arm of the second bridge arm BA121, the upper bridge arm of the second bridge arm BA121 includes a third switch Q3, the lower bridge arm of the second bridge arm BA121 includes a fourth switch Q4, and the second node P2 is a connection point between the third switch Q3 and the fourth switch Q4. The first bridge arm BA121 is connected in parallel with the second bridge arm BA122, the bus capacitor C1, and the first heating module H1, and is electrically connected with the energy storage inverter 10, wherein the voltage on the bus capacitor C1 is the input voltage of the first heating module H1.

[0037] Specifically, Figure 3 The voltage conversion circuit BA12 has the following three working modes:

[0038] The first working mode: the upper bridge arm and the lower bridge arm of the same bridge arm are in a complementary state, that is, the upper bridge arm is turned on when the lower bridge arm is turned off, and the lower bridge arm is turned on when the upper bridge arm is turned off, for example, the first switch Q1 is turned on when the second switch Q2 is turned off. At this time, the battery cell module BA11 can be charged or discharged.

[0039] The second working mode: the upper bridge arms of each bridge arm are kept off, and the lower bridge arms are alternately turned on and turned off, that is, the first switch Q1 and the third switch Q3 are kept off, and the second switch Q2 and the fourth switch Q4 are alternately turned on and turned off under the control of the pulse width modulation signal, so as to step up the voltage of the battery cell module BA11. At this time, the battery cell module BA11 can only be discharged, that is, the direction of the current loop of the voltage conversion circuit BA12 remains the direction of discharging the battery cell module BA11. Thus, when the energy storage inverter 10 controls the voltage (i.e., the bus voltage) of the bus capacitor C1 to rise, the battery cell module BA11 will not be charged, but only the input voltage of the first heating module H1 will rise.

[0040] The third working mode: the lower bridge arms of each bridge arm are kept off, and the upper bridge arms are alternately turned on and off, that is, the second switch tube Q2 and the fourth switch tube Q4 are kept off, and the first switch tube Q1 and the third switch tube Q3 are alternately turned on and off under the control of the pulse width modulation signal, so as to step down the voltage output by the energy storage inverter 10, and charge the battery cell module BA11. At this time, the battery cell module BA11 can only be charged, that is, the direction of the current loop of the voltage conversion circuit BA12 is kept as the direction of charging the battery cell module BA11.

[0041] It should be noted that the hardware structure of the energy storage system 100 as shown is only an example, and the energy storage system 100 can have more or fewer components than those shown in the figure, two or more components can be combined, or have a different component configuration, and various components shown in the figure can be implemented in hardware, software, or a combination of hardware and software, including one or more signal processing and / or application specific integrated circuits. Figures 1-3

[0042] For example, as shown in Figure 4 The energy storage system 100 further includes an energy control module 30 and a switch module 20. The switch module 20 is electrically connected between the N battery packs and the energy storage inverter 10, and the energy control module 30 is electrically connected with the switch module 20 to control the switch module 20 to establish or break the electrical connection between the N battery packs and the energy storage inverter 10. The energy control module 30 is in communication connection with the energy storage inverter 10. In some embodiments, the switch module 20 includes a relay.

[0043] Please refer to Figure 5 , Figure 5 The flowchart of the heating control method provided by the embodiments of the present application. Wherein, the heating control method is applied to an energy storage system, and in some embodiments, the energy storage system can be implemented by the circuit structure as shown in Figures 1-4 The specific implementation process has been described in detail in the above embodiments, which will not be repeated here. As shown in Figure 5 The heating control method includes the following steps S510 to S530.

[0044] Step S510: When the battery pack determines to heat, the direction of the current loop of the voltage conversion circuit is controlled to keep the direction of discharging the battery cell module.

[0045] Specifically, when the energy storage system starts to run, each battery pack performs self-checking and judges whether heating is needed. When the battery pack determines that heating is needed, the direction of the current loop of the voltage conversion circuit is first controlled to keep the direction of discharging the battery cell module, so as to ensure that the voltage of the heating module can be lifted while the voltage of the battery cell module is not lifted, which is beneficial to effectively improve the heating power of the heating module on the one hand, and can play a role in protecting the battery cell module on the other hand.​

[0046] by Figure 3 For example, control Figure 3 The voltage conversion circuit BA12 shown is in the second working mode so that the direction of the current loop of the voltage conversion circuit BA12 is kept in the direction of discharge of the cell module BA11, so as to ensure that the voltage of the first heating module H1 can be raised while the voltage of the cell module BA11 is not raised.

[0047] Step S520: The battery pack obtains the current temperature of the heating module and determines the target heating power of the heating module based on the current temperature of the heating module.

[0048] In one specific embodiment, the current temperature of the heating module (i.e., the actual temperature of the heating module) can be obtained by setting a temperature sensor (such as a thermistor). Specifically, the temperature sensor can generate a corresponding detection signal to the battery pack based on the current temperature of the heating module, and the battery pack determines the current temperature of the heating module based on the detection signal.

[0049] The target heating power is the desired heating power. Determining the target heating power of the heating module based on its current temperature enables a temperature-based linear power limiting strategy, achieving smooth temperature control and preventing overheating.

[0050] In some embodiments, such as Figure 6 As shown, the specific implementation process of step S520 includes the following step S610.

[0051] Step S610: The battery pack determines the target heating power based on the minimum value between the maximum heating power supported by the heating module and the first target power, wherein the first target power is the heating power that can be achieved based on the real-time temperature of the heating module.

[0052] Specifically, the maximum heating power supported by the heating module refers to the highest electrical power input value that the heating module can operate safely and stably for a long period of time under specified voltage, ambient temperature, and heat dissipation conditions. The maximum heating power supported by the heating module is usually determined by factors such as the resistance and temperature resistance of the heating material. If the actual heating power of the heating module exceeds the maximum heating power supported by the heating module, it may lead to localized overheating or even short circuits and fires.

[0053] Therefore, if the first target power is less than the maximum heating power supported by the heating module, the abnormal situation will not occur, and the first target power can be directly used as the target heating power. If the first target power is greater than or equal to the maximum heating power supported by the heating module, the abnormal situation may occur, and the maximum heating power supported by the heating module should be used as the target heating power to avoid the abnormal situation and improve the safety and reliability of the entire system.

[0054] In some embodiments, the first target power Pac is: Pac = Pmax - (T - T1) / (T2 - T1) * Pmax, where Pmax is the maximum heating power, T is the current temperature, T1 is the minimum operating temperature for maintaining the heating demand, and T2 is the upper limit of the temperature of the heating module.

[0055] The minimum operating temperature for maintaining the heating demand refers to the lowest temperature at which heat needs to be provided to maintain basic functions. When T ≤ T1, the system determines that "heating is needed" and starts heating. When T > T1, the system can enter the power limiting mode.

[0056] The upper limit of the temperature of the heating module refers to a safety upper limit temperature threshold, which indicates the highest temperature that the heating module can reach under any working condition (including failure, poor heat dissipation, control failure, etc.). Once the temperature reaches or exceeds the threshold, the heating power must be immediately cut off or significantly reduced to prevent safety accidents such as material damage, fire, and burns. The upper limit of the temperature of the heating module is also the over-temperature protection point.

[0057] By obtaining the target heating power based on the first target power Pac, a closed-loop control process of the heating power of the heating module can be achieved. Specifically, when the current temperature T is less than T1, the heating module always heats at the maximum heating power Pmax. When the current temperature T is between T1 and T2, the heating power of the heating module gradually decreases to 0. Thus, smooth temperature control can be achieved and overheating can be prevented.

[0058] Step S530: The energy storage inverter obtains the target heating power and adjusts the input voltage of the heating module according to the target heating power to adjust the heating power of the heating module.

[0059] Specifically, since the voltage conversion circuit is controlled to be in the second working mode in the foregoing step, the direction of the current loop of the voltage conversion circuit is maintained as the direction of discharging the battery module. Therefore, when the bus voltage is adjusted by the energy storage inverter to increase, the battery module will not be charged, and the increased voltage will mainly act on the heating module as the input voltage of the heating module. According to P = U 2With the increase of the input voltage U of the heating module, the heating power P of the heating module also increases, which is beneficial to realize fast heating of the battery pack to ensure that the battery pack can be normally used.

[0060] In some embodiments, as shown in FIG. 7, the specific implementation process of step S530 includes steps S710-S720. Figure 7

[0061] Step S710: The energy storage inverter determines a target input voltage of the heating module based on the target heating power.

[0062] Step S720: When the current input voltage of the heating module is less than the target input voltage, the power output by the energy storage inverter increases the input voltage of the heating module to increase the heating power of the heating module.

[0063] Specifically, when the current input voltage is less than the target input voltage, it means that the current heating power of the heating module has not reached the target heating power, and then the energy storage inverter outputs power to charge the bus capacitor to increase the input voltage of the heating module, so as to increase the heating power of the heating module.

[0064] In some embodiments, the specific implementation process of step S710 includes steps S810-S820.

[0065] Step S810: The energy storage inverter determines a first target voltage based on the arithmetic square root of the product of the target heating power and the resistance value of the heating module.

[0066] Specifically, according to the formula P=U 2 / R, it can be obtained that U is equal to the arithmetic square root of P*R. Based on this, the first target voltage is equal to the arithmetic square root of the product of the target heating power and the resistance value of the heating module.

[0067] Step S820: The energy storage inverter determines the target input voltage based on the minimum value between the first target voltage and the upper limit value of the input voltage of the heating module, wherein the upper limit value of the input voltage of the heating module is the minimum value of the maximum voltage that the bus capacitor can withstand and the maximum voltage that the heating module can withstand.

[0068] ​The maximum voltage that the bus capacitor can withstand refers to the highest DC voltage value that the bus capacitor can safely and stably work for a long time, which is usually the rated voltage of the bus capacitor. If the voltage on the bus capacitor exceeds the maximum voltage that the bus capacitor can withstand, the bus capacitor may be broken down, the capacitor may fail and form a short circuit, and then a large instantaneous current may occur, which may not only damage the devices in the energy storage system but also may cause the capacitor to explode and cause a fire. The maximum voltage that the heating module can withstand refers to the highest power supply voltage that the heating module can apply under the condition of long-term, continuous and safe operation, which can also be understood as the maximum working voltage of the heating module. If the voltage applied to the heating module exceeds the maximum voltage that the heating module can withstand, the heating module may fail or even catch fire.

[0069] Therefore, if the first target voltage is less than the upper limit value of the input voltage of the heating module, the bus capacitor will not be broken down or the heating module will not fail, and the like. At this time, the first target voltage can be directly used as the target input voltage. Conversely, if the first target voltage is greater than or equal to the upper limit value of the input voltage of the heating module, the bus capacitor may be broken down or the heating module may fail, and the like. At this time, the upper limit value of the input voltage of the heating module should be used as the target input voltage to avoid the bus capacitor being broken down or the heating module failing, and the like, and to improve the safety and reliability of the entire system.

[0070] In some embodiments, as shown in FIG. 9, the heating control method further includes steps S910 to S920. Figure 9

[0071] Step S910: When the energy storage inverter determines that the actual heating power of the heating module is greater than or equal to the maximum heating power supported by the heating module, and / or when the energy storage inverter determines that the input voltage of the heating module is greater than or equal to the upper limit value of the input voltage of the heating module, the energy storage inverter controls the power output by the energy storage inverter to remain unchanged.

[0072] Step S920: When the energy storage inverter determines that the actual temperature of the heating module is greater than or equal to the upper limit value of the temperature of the heating module, the energy storage inverter outputs a first signal to the energy control module to make the energy control module control the switch module to disconnect the electrical connection between the N battery packs and the energy storage inverter.

[0073] ​Specifically, as known from the foregoing, if the actual heating power of the heating module is greater than or equal to the maximum heating power supported by the heating module, it can cause local overheating or even short-circuit fire; if the input voltage of the heating module is greater than or equal to the upper limit of the input voltage of the heating module, it can cause the bus capacitor to be broken down, and thus the devices in the energy storage system can be damaged or even cause a capacitor explosion and a fire. In this case, the power output by the energy storage inverter remains unchanged, and thus the input voltage of the heating module also remains unchanged, so as to reduce the risk of damage to the heating module and the bus capacitor.

[0074] Under the premise that the power output by the energy storage inverter remains unchanged, when the actual temperature of the heating module is greater than or equal to the upper limit of the temperature of the heating module, the energy storage inverter outputs a first signal to the energy control module, so that the energy control module controls the switch module to disconnect the electrical connection between the N battery packs and the energy storage inverter. On the one hand, since the electrical connection between the N battery packs and the energy storage inverter is disconnected, the energy storage inverter has no power output and thus no loss, which can improve the efficiency. On the other hand, since the power provided by the energy storage inverter is lost, the bus voltage, the temperature of the heating module and the heating power will gradually decrease, so as to ensure that the bus voltage, the temperature of the heating module and the heating power can be kept within a safe range, which is conducive to ensuring that the system has high reliability and safety.

[0075] In some embodiments, as shown in FIG. 10, after the energy storage inverter outputs the first signal to the energy control module in step S910, the heating control method further includes the following step S1010. Figure 10

[0076] Step S1010: When it is determined that the current temperature of the heating module is less than the minimum operating temperature for maintaining the heating requirement, the energy storage inverter outputs a second signal to the energy control module, so that the energy control module controls the switch module to establish the electrical connection between the N battery packs and the energy storage inverter.

[0077] Specifically, after the energy storage inverter outputs the first signal to the energy control module, although the bus voltage, the temperature of the heating module and the heating power will gradually decrease, the heating module is still heating the battery packs at this time. If the temperature of the heating module decreases to less than the minimum operating temperature for maintaining the heating requirement, it will result in poor heating effect on the battery packs. Therefore, it is necessary to close the switch module again to re-establish the electrical connection between the N battery packs and the energy storage inverter, so that the bus voltage, the temperature of the heating module and the heating power will gradually increase to achieve effective heating of the battery packs. The above process is repeatedly performed until the heating process of the battery packs is completed.

[0078] ​In the embodiments of the present application, when the battery pack is heated, the direction of the current loop of the voltage conversion circuit is controlled to remain the direction of discharging the cell module, so as to ensure that the voltage of the heating module can be lifted while the voltage of the cell module is not lifted, which is beneficial to effectively improve the heating power of the heating module on the one hand, and can protect the cell module on the other hand. Secondly, the energy storage inverter can provide larger power to make the heating module have larger heating power, so as to realize effective heating of the battery while reducing switching loss and improving efficiency. Thirdly, when the actual heating power of the heating module is greater than or equal to the maximum heating power supported by the heating module, and / or when the input voltage of the heating module is greater than or equal to the upper limit value of the input voltage of the heating module, the power output by the energy storage inverter is maintained unchanged; then, when the actual temperature of the heating module is greater than or equal to the upper limit value of the temperature of the heating module, the switch module disconnects the electrical connection between the N battery packs and the energy storage inverter, which not only can ensure that the bus voltage, the temperature and the heating power of the heating module are kept within a safe range, so as to reduce the risk of damage of the heating module and the bus capacitor, but also can improve the conversion efficiency, so as to reduce the switching loss. In addition, by increasing the bus voltage to increase the heating power in a way, the heating time can be shortened, and the battery pack can be used normally.

[0079] The embodiments of the present application also provide a non-volatile computer readable storage medium, which stores computer executable instructions, the computer executable instructions are executed by one or more processors, for example, the method steps of the above described Figures 5-10 are executed.

[0080] The embodiments of the present application also provide a computer program product, which includes a computer program stored on a non-volatile computer readable storage medium, the computer program includes program instructions, when the program instructions are executed by a computer, the computer executes the heating control method in any method embodiment described above, for example, the method steps of the above described Figures 5-10 are executed.

[0081] The above description is only the embodiments of the present application, and does not limit the patent scope of the present application, and any equivalent structure or equivalent process transformation using the content of the specification and drawings of the present application, or direct or indirect application in other related technical fields, are also included in the patent protection scope of the present application.

[0082] The above examples are only used to illustrate the technical solutions of the present application, and are not intended to limit the present application; under the idea of the present application, the technical features in the above examples or different examples can also be combined, and the steps can be implemented in any order. Those skilled in the art should understand that the technical solutions recorded in the foregoing examples can still be modified, or some technical features can be replaced by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the examples of the present application.

Claims

1. A heating control method, characterized in that, An application is made in an energy storage system, the energy storage system comprising N battery packs, N heating modules, and an energy storage inverter. Each battery pack corresponds one-to-one with a heating module, and the N battery packs are communicatively connected to the energy storage inverter. Each battery pack includes a cell module and a voltage conversion circuit. The voltage conversion circuit is electrically connected to the cell module, the energy storage inverter, and the heating module, respectively. Each cell module includes at least one cell, where N is a positive integer. The voltage conversion circuit includes a first inductor, a second inductor, a first bridge arm, and a second bridge arm. The first inductor is electrically connected between the positive terminal of the cell module and a first node of the first bridge arm, the first node being the connection point between the upper and lower bridge arms of the first bridge arm. The second inductor is electrically connected between the positive terminal of the cell module and a second node of the second bridge arm, the second node being the connection point between the upper and lower bridge arms of the second bridge arm. The first bridge arm, the second bridge arm, and the bus capacitor in the voltage conversion circuit are connected in parallel. The method includes: When the battery pack is determined to be heated, the direction of the current loop of the voltage conversion circuit is controlled to remain in the direction of discharge of the cell module; The battery pack acquires the current temperature of the heating module and determines the target heating power of the heating module based on the current temperature of the heating module. The energy storage inverter acquires the target heating power and adjusts the input voltage of the heating module according to the target heating power to adjust the heating power of the heating module; The step of controlling the direction of the current loop of the voltage conversion circuit to remain in the direction of discharge of the cell module includes: The battery pack controls the upper arms of the first and second bridge arms to remain off, and controls the lower arms of the first and second bridge arms to alternately turn on and off, so as to keep the direction of the current loop of the voltage conversion circuit in the direction of the cell module's discharge.

2. The heating control method according to claim 1, characterized in that, The step of the battery pack acquiring the current temperature of the heating module and determining the target heating power of the heating module based on the current temperature of the heating module includes: The battery pack determines the target heating power based on the minimum value between the maximum heating power supported by the heating module and the first target power, wherein the first target power is the heating power that can be achieved based on the real-time temperature of the heating module.

3. The heating control method according to claim 2, characterized in that, The first target power Pac is: Pac=Pmax-(T-T1) / (T2-T1)*Pmax, where Pmax is the maximum heating power, T is the current temperature, T1 is the minimum operating temperature to maintain the heating requirement, and T2 is the upper limit of the temperature of the heating module.

4. The heating control method according to claim 1, characterized in that, The step of adjusting the heating power of the heating module by adjusting the input voltage of the heating module according to the target heating power by the energy storage inverter includes: The energy storage inverter determines the target input voltage of the heating module based on the target heating power; When the current input voltage of the heating module is less than the target input voltage, the energy storage inverter outputs power to increase the input voltage of the heating module, thereby increasing the heating power of the heating module.

5. The heating control method according to claim 4, characterized in that, The voltage conversion circuit includes a bus capacitor electrically connected to the heating module, and the voltage on the bus capacitor is the input voltage of the heating module. The step of determining the target input voltage of the heating module based on the target heating power by the energy storage inverter includes: The energy storage inverter determines the first target voltage based on the square root of the product of the target heating power and the resistance value of the heating module; The energy storage inverter determines the target input voltage based on the minimum value between the first target voltage and the upper limit of the input voltage of the heating module, wherein the upper limit of the input voltage of the heating module is the minimum value between the maximum voltage that the bus capacitor can withstand and the maximum voltage that the heating module can withstand.

6. The heating control method according to claim 1, characterized in that, The energy storage system further includes an energy control module and a switch module. The switch module is electrically connected between the N battery packs and the energy storage inverter. The energy control module is electrically connected to the switch module to control the switch module to establish or disconnect the electrical connection between the N battery packs and the energy storage inverter. The energy control module is communicatively connected to the energy storage inverter. The method further includes: When the energy storage inverter determines that the actual heating power of the heating module is greater than or equal to the maximum heating power supported by the heating module, and / or when the energy storage inverter determines that the input voltage of the heating module is greater than or equal to the upper limit of the input voltage of the heating module, the energy storage inverter controls its output power to remain unchanged. When the energy storage inverter determines that the actual temperature of the heating module is greater than or equal to the upper limit of the heating module's temperature, the energy storage inverter outputs a first signal to the energy control module, so that the energy control module controls the switching module to disconnect the electrical connection between the N battery packs and the energy storage inverter.

7. The heating control method according to claim 6, characterized in that, After performing the step of outputting a first signal from the energy storage inverter to the energy control module, the method further includes: When the energy storage inverter determines that the current temperature of the heating module is lower than the minimum operating temperature required to maintain heating, the energy storage inverter outputs a second signal to the energy control module, so that the energy control module controls the switching module to establish electrical connections between N battery packs and the energy storage inverter.

8. An energy storage system, characterized in that, It includes N battery packs, N heating modules, and energy storage inverters, where N is a positive integer; The battery pack corresponds one-to-one with the heating module, and N battery packs are communicatively connected to the energy storage inverter. The battery pack includes a cell module and a voltage conversion circuit. The voltage conversion circuit is electrically connected to the cell module, the energy storage inverter and the heating module respectively. The cell module includes at least one cell. Wherein, the battery pack is used to perform the method steps performed by the battery pack in the heating control method as described in any one of claims 1-7, and the energy storage inverter is used to perform the method steps performed by the energy storage inverter in the heating control method as described in any one of claims 1-7.

9. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program that, when executed, implements the heating control method as described in any one of claims 1-7.

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