Battery heating control method, battery management system, and computer-readable storage medium

Abstract

The embodiment of the present application relates to the field of battery, and especially relates to a battery heating control method, a battery management system and a computer readable storage medium, wherein an energy benefit table of the battery is acquired, the energy benefit table represents the corresponding relationship among the battery temperature, the battery SOC and the energy benefit value, the energy benefit value comprises a first value and a second value, the first value represents the positive benefit of heating energy, and the second value represents the negative benefit of heating energy; the battery temperature is monitored, if the battery temperature is lower than a first temperature threshold value and the battery is in a discharging state, the battery SOC is acquired, the energy benefit value is determined based on the battery temperature, the battery SOC and the energy benefit table, if the energy benefit value is the first value, the battery is controlled to supply power for an external heat source.In the case of low temperature of the battery, according to the trade-off of the heating energy benefit, the battery is controlled to supply power for the external heat source to heat in the discharging state, and the battery performance is improved.

Description

TECHNICAL FIELD

[0001] Embodiments of the present application relate to the field of batteries, and in particular to a battery heating control method, a battery management system and a computer readable storage medium. BACKGROUND

[0002] With the popularization of electric vehicles, electric tools and other applications, lithium batteries, as a high-efficiency, environmentally friendly energy storage method, are increasingly widely used. However, in a low-temperature environment, the lithium battery has poor performance and severely limits its use in cold regions due to the increase in internal resistance, the decrease in lithium ion migration rate, and the resulting attenuation of effective capacity. In order to solve this problem, researchers have developed various active / passive heating strategies to improve the temperature of the battery, reduce the internal resistance of the battery, and improve the electrochemical reaction activity, thereby restoring part of the available capacity and improving the performance of the lithium battery in a low-temperature environment.

[0003] For the method of heating the battery by an external heat source, the prior art usually uses mains (power grid) to power the external heat source, such as providing power to the external heat source while charging the battery with the power grid, so that the external heat source generates heat to heat the battery. This method requires users to pay for the "electricity bill", resulting in additional expenses and burdening users. To avoid additional expenses, renewable energy sources such as photovoltaic power may also be used to power the external heat source, but photovoltaic power generation is greatly affected by light, day and night alternation, weather changes (such as cloud cover, rainy weather), and seasonal changes.

[0004] The existing battery heating strategy by an external heat source generally focuses on improving the temperature of the battery by means of external energy input, but all ignore a potentially promising approach, that is, skillfully using the energy of the battery itself to drive the external heat source to achieve efficient heating of the battery. The deep-seated reason for this phenomenon is that due to the complex electrochemical mechanism inside the battery and the multiple influences of external environmental factors, it is difficult to accurately weigh the negative energy gain from the consumed energy during the heating process against the positive gain of the available capacity increase of the battery due to the temperature rise, thereby limiting the further development of battery heating technology in terms of energy consumption optimization and performance improvement. In addition, in the selection process of the power grid, photovoltaic and other renewable energy sources, and batteries and other driving sources, due to the complexity and diversity of working conditions, the control strategies currently developed for different working conditions are not perfect enough, and it is difficult to fully utilize the advantages of various driving sources, resulting in deficiencies in adaptability and effectiveness. SUMMARY

[0005] The technical problem solved by the embodiments of the present application is to provide a battery heating control method that can balance energy gains in a low-temperature battery to heat the battery and improve battery performance.

[0006] In a first aspect, embodiments of the present application provide a battery heating control method, comprising:

[0007] obtaining an energy benefit table of the battery, the energy benefit table representing a correspondence relationship among a battery temperature, a battery SOC and an energy benefit value, the energy benefit value including a first value and a second value, the first value representing a positive benefit of heating with energy, and the second value representing a negative benefit of heating with energy;

[0008] monitoring the battery temperature;

[0009] if the battery temperature is lower than a first temperature threshold and the battery is in a discharging state, obtaining a battery SOC, and determining an energy benefit value based on the battery temperature, the battery SOC and the energy benefit table;

[0010] if the energy benefit value is the first value, controlling the battery to supply power to an external heat source.

[0011] In some embodiments, the method further comprises:

[0012] if the battery temperature is lower than the first temperature threshold and the battery is in a charging state, controlling an external charging device to supply power to the external heat source until the battery temperature reaches the first temperature threshold.

[0013] In some embodiments, the method further comprises:

[0014] if the battery temperature is lower than the first temperature threshold, in response to a received user instruction, determining a heating start time according to the user instruction, the user instruction including at least one of a scheduled discharging, a scheduled charging and a scheduled heating;

[0015] after the heating start time is reached, obtaining a first state of the battery;

[0016] if the first state of the battery is a stationary state and the battery SOC is greater than or equal to a first power threshold, controlling the battery to supply power to the external heat source;

[0017] if the battery SOC is less than the first power threshold, and the external charging device is in an allowed charging state, controlling the external charging device to supply power to the external heat source until the battery temperature reaches the first temperature threshold.

[0018] In some embodiments, the method further comprises:

[0019] If the first state of the battery is a resting state and the SOC of the battery is less than the first power threshold, when the external charging device is in a charging-allowed state, controlling the external charging device to supply power to the external heat source until the battery temperature reaches a first temperature threshold, and when the external charging device is in a charging-not-allowed state, controlling the battery to supply power to the external heat source until the battery temperature reaches the first temperature threshold.

[0020] In some embodiments, the method further comprises:

[0021] If the first state of the battery is a charging state, controlling the external charging device to supply power to the external heat source until the battery temperature reaches a first temperature threshold.

[0022] If the first state of the battery is a discharging state, controlling the battery to supply power to the external heat source until the battery temperature reaches a first temperature threshold.

[0023] In some embodiments, the controlling the external charging device to supply power to the external heat source comprises:

[0024] If the charging current of the external charging device is greater than the required current of the external heat source and the battery is in a charging-allowed state, controlling the external charging device to supply power to the external heat source and the battery simultaneously.

[0025] If the charging current of the external charging device is less than the required current of the external heat source and the battery is in a discharging-allowed state, controlling the external charging device and the battery to supply power to the external heat source simultaneously.

[0026] In some embodiments, the method further comprises:

[0027] If the user instruction further comprises a temperature-maintaining instruction, after the battery temperature reaches the first temperature threshold, continuing to control the external heat source to heat until the battery temperature reaches a second temperature threshold, the second temperature threshold being higher than the first temperature threshold.

[0028] In some embodiments, the external charging device comprises an energy storage inverter and a photovoltaic.

[0029] The method further comprises:

[0030] If the output power of the photovoltaic is greater than or equal to a first power threshold and the battery temperature is less than a third temperature threshold, controlling the photovoltaic to supply power to the external heat source until the battery temperature reaches the third temperature threshold.

[0031] In some embodiments, the method further comprises:

[0032] Monitoring a power grid price.

[0033] If the grid price is higher than the preset price and the battery SOC is greater than the second power threshold, the energy storage converter is set to a no-charge state to close the battery charging and heating request.

[0034] In some embodiments, the method for obtaining the energy benefit table comprises:

[0035] The battery is subjected to charging / discharging test and standing test at different ambient temperatures, and test data of the battery are recorded, and a battery self-heating temperature prediction model is established based on the test data;

[0036] The dischargeable capacity of the battery under different currents, different battery temperatures and different battery SOCs is obtained to form a dischargeable capacity table;

[0037] The discharge self-heating simulation of the battery is performed according to the battery self-heating temperature prediction model and the dischargeable capacity table to form an energy benefit table of the battery.

[0038] In a second aspect, the embodiments of the present application provide a battery management system, comprising a memory, a processor and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of the battery heating control method according to the first aspect.

[0039] In a third aspect, the embodiments of the present application provide a non-volatile computer readable storage medium, characterized in that the computer readable storage medium stores computer executable instructions, when the computer executable instructions are executed by at least one processor, the at least one processor executes the steps of the battery heating control method according to the first aspect.

[0040] The battery heating control method provided by the embodiments of the present application is different from the prior art. Firstly, by monitoring the battery temperature, when the battery temperature is lower than the first temperature threshold, the battery itself is used to drive the external heat source to realize self-heating of the battery, thereby reducing the user's cost expenditure. Secondly, the energy benefit table is obtained, the battery temperature and the battery SOC are combined, and the real-time energy benefit value is calculated; when the heating has a positive energy benefit, the battery is controlled to supply power to the external heat source, not only realizing the battery temperature rise and improving the battery performance, but also making the positive gain of the battery available capacity increase exceed the electric energy consumed by the heating system, thereby realizing the positive energy benefit. BRIEF DESCRIPTION OF DRAWINGS

[0041] One or more embodiments are illustrated by way of example in the drawings and are described herein in connection with the embodiments presented. The embodiments disclosed herein are not intended to be exhaustive or to limit the claims to the precise form disclosed. The drawings are not necessarily to scale and the dimensions of the various features can have been generalized in order to illustrate the embodiments.

[0042] Figure 1 An application environment schematic diagram of a battery heating control method provided by an embodiment of the present application is shown in the figure.

[0043] Figure 2 An application environment schematic diagram of a battery heating control method provided by another embodiment of the present application is shown in the figure.

[0044] Figure 3 An application environment schematic diagram of a battery heating control method provided by another embodiment of the present application is shown in the figure.

[0045] Figure 4 An application environment schematic diagram of a battery heating control method provided by another embodiment of the present application is shown in the figure.

[0046] Figure 5 A structure block diagram of a battery management system provided by an embodiment of the present application is shown in the figure.

[0047] Figure 6 A flow schematic diagram of a battery heating control method provided by an embodiment of the present application is shown in the figure.

[0048] Figure 7 A flow schematic diagram of an energy income table acquisition method provided by an embodiment of the present application is shown in the figure.

[0049] Figure 8 A flow schematic diagram of a battery heating control method provided by another embodiment of the present application is shown in the figure.

[0050] Figure 9 A true value representation of an energy income table provided by an embodiment of the present application is shown in the figure. DETAILED DESCRIPTION

[0051] The present application will be described in detail below with specific embodiments. The following embodiments will help those skilled in the art to further understand the present application, but do not limit the present application in any form. It should be noted that those skilled in the art can make several modifications and improvements without departing from the concept of the present application. These are within the scope of protection of the present application.

[0052] In order to make the purpose, technical solutions and advantages of the present application clearer, the present application is further described in detail below in combination with the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and do not limit the present application.

[0053] It should be noted that the various features of the embodiments of the present application can be combined with each other, and all within the scope of the present application, if there is no conflict. In addition, although the functional modules are divided in the device schematic diagram, and the logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in a different order than the module division in the device or the order in the flowchart. In addition, the terms "first", "second", "third" and the like used herein do not limit the data and execution order, but only distinguish the same items or similar items with basically the same function and effect.

[0054] Unless otherwise defined, all technical and scientific terms used in the specification are the same as those commonly understood by those skilled in the art to which the present application belongs. The terms used in the specification of the present application are only for the purpose of describing the specific embodiments and are not used to limit the present application. The term "and / or" used in the specification includes any and all combinations of one or more related listed items.

[0055] In addition, the technical features involved in each embodiment of the present application described below can be combined with each other as long as there is no conflict.

[0056] Figures 1-4 is a schematic diagram of the application environment of the battery heating control method provided by the embodiments of the present application. Please refer to Figures 1-4 , the application environment includes a battery 10, an external heat source 20, an external charging device 30 and a load 40. In the figure, the solid line represents the flow of electric (energy), and the dashed line represents the flow of heat.

[0057] When the battery is in a low-temperature environment, the performance of the battery will be affected, so the battery needs to be heated to prevent the performance of the battery from decreasing or freezing in a low-temperature environment. The low-temperature standard in the low-temperature environment can be set by the user according to the actual situation, or determined according to the performance of each battery, or obtained according to big data statistics, etc. For example, the low-temperature environment can be an environment with a temperature lower than minus 20 degrees Celsius.

[0058] The battery 10 can be a lithium ion battery, a lithium polymer battery, a nickel-hydrogen battery or various types of batteries, and the present application does not limit this. The battery 10 is connected to the external heat source 20, and the battery 10 is heated and kept warm by the external heat source 20. In some embodiments, the battery 10 supplies power to the external heat source 20. The battery 10 is electrically connected to the external charging device 30, and the battery 10 is charged by the external charging device 30. The battery 10 is electrically connected to the load 40, and the battery 10 supplies power to the load 40 by discharging.

[0059] The external heat source 20 is connected to the battery 10, and the external heat source 20 heats the battery 10. In some embodiments, the battery 10 supplies power to the external heat source 20 to heat the battery. In some embodiments, the external heat source 20 is connected to the external charging device 30, and the external charging device 30 supplies power to the external heat source 20, so that the external heat source 20 can heat the battery. For example, the external heat source 20 can be a lithium battery heating sheet, a graphene heating film, or an electrolyte heater, and the present application does not limit the same.

[0060] Please refer to Figures 1-4 In some embodiments, the battery 10 supplies power to the external heat source 20 and the load 40 at the same time, and the external heat source 20 heats the battery 10. In some embodiments, the external charging device 30 supplies power to the battery 10 and the external heat source 20 at the same time, and the battery 10 is charged and the external heat source 20 heats the battery 10. In some embodiments, the battery 10 supplies power to the external heat source 20, and the external heat source 20 heats the battery 10. In some embodiments, the external charging device 30 supplies power to the external heat source 20, and the external heat source 20 heats the battery 10.

[0061] In order to solve the problems that the battery is easily affected by the low temperature environment, the heating time of the battery is not easy to control, and the heating energy benefit cannot be balanced, one embodiment of the present application provides a battery heating control method. The battery heating control method is executed by the battery management system 50, can save user cost, balance energy benefit, heat the battery, and improve the performance of the battery under the condition of low temperature of the battery.

[0062] Before the battery heating control method is described in detail, the hardware structure of the battery management system provided by another embodiment of the present application is described.

[0063] On the basis of the above Figures 1-4 , another embodiment of the present application provides a battery management system, as shown in Figure 5 , the battery management system 50 includes at least one processor 51 and a memory 52 connected in communication (for example, one processor is connected by a bus) Figure 5 . Those skilled in the art can understand that Figure 5 the structure shown is only schematic, and does not limit the structure of the above-mentioned electronic device. For example, the battery management system 50 can include more or fewer components than those shown in Figure 5 , or have a different configuration from Figure 5 .

[0064] The processor 51 is configured to provide computing and control capabilities to control the battery management system 50 to perform corresponding tasks, for example, to control the battery management system 50 to perform any one of the battery heating control methods provided in the embodiments of the present application.

[0065] It can be understood that the processor 51 can be a general-purpose processor, including a central processing unit (CPU), a network processor (NP), etc., and can also be a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA) or other programmable logic device, a discrete gate or transistor logic device, a discrete hardware component.

[0066] The memory 52 is a non-transitory computer-readable storage medium, which can be configured to store non-transitory software programs, non-transitory computer-executable programs and modules, such as program instructions / modules corresponding to the battery heating control method in the embodiments of the present application. The processor 51 can implement the battery heating control method in any one of the method embodiments by running the non-transitory software programs, instructions and modules stored in the memory 52. The memory 52 can include a high-speed random access memory, and can also include a non-transitory memory, such as at least one magnetic disk storage device, a flash memory device, or other non-transitory solid-state memory device. In some embodiments, the memory 52 can also include a memory remotely arranged with respect to the processor, and these remote memories can be connected to the processor through a network. Examples of the above-mentioned network include but are not limited to the Internet, an intranet, a local area network, a mobile communication network, and a combination thereof.

[0067] The battery heating control method provided in the embodiments of the present application will be described in detail below. Please refer to Figure 6 , the battery heating control method includes but is not limited to the following steps S101-S105:

[0068] S101: Obtain the energy benefit table of the battery, the energy benefit table representing the correspondence between the battery temperature, the battery SOC and the energy benefit value, the energy benefit table including a first value and a second value, the first value representing positive benefit of heating energy, and the second value representing negative benefit of heating energy.

[0069] In some embodiments, the first value is 1, and the second value is 0.

[0070] In some embodiments, please refer toFigure 7 The method for obtaining the energy yield table comprises steps S201-S203:

[0071] S201: performing charge / discharge test and standing test on the battery at different ambient temperatures, recording test data of the battery, and establishing a battery self-heating temperature prediction model based on the test data.

[0072] The test data of the battery includes ambient temperature, charge / discharge current, temperature of the battery, charge / discharge duration, standing duration, etc.

[0073] Step S201 specifically comprises steps S2011 and S2012.

[0074] S2011: performing charge / discharge test and standing test on the battery at different ambient temperatures to obtain model parameters of the battery.

[0075] The test is divided into two stages, namely, a charge / discharge stage and a standing stage.

[0076] Taking the discharge test in the first stage as an example, the battery is discharged at a constant current of 0.5C in a low-temperature oven at -40°C and in an environment with a humidity of 50%.

[0077] At the beginning of the discharge test, the temperature of the battery is equal to the ambient temperature. As the discharge proceeds, the temperature of the battery rises. After the discharge ends, the thermal power of the battery is:

[0078]

[0079] Wherein, P all_1 represents the thermal power of the battery at the end of the discharge, P bat_1 represents the self-generated heat power of the battery due to charge / discharge, and P env_1 represents the heat power exchanged with the environment by convection during the charge / discharge process.

[0080] According to the general formula of thermal energy calculation, Joule's law and the principle of convective heat transfer, P all_1 , P bat_1 and P env_1 can be respectively represented as follows:

[0081]

[0082] Wherein, c represents the specific heat capacity of the battery, m represents the mass of the battery, T0 represents the temperature of the battery at the beginning of charge / discharge, which is equal to the ambient temperature, T1 represents the temperature of the battery at the end of charge / discharge, t1 represents the duration of charge / discharge, K represents the equivalent battery self-heat power coefficient, I represents the current of the battery during charge / discharge, R represents the thermal equivalent internal resistance of the battery, and Ku represents the environmental heat dissipation coefficient.

[0083] Wherein, the mass m, the specific heat capacity c and the thermal equivalent resistance R of the battery can be measured by experiment or provided by the battery manufacturer.

[0084] In the static phase, due to the initial battery temperature is higher than the ambient temperature, the battery and the environment convective exchange, the battery temperature gradually decreases, and the battery temperature is equal to the ambient temperature after the static phase, and the thermal power is:

[0085]

[0086] Wherein, P all_2 represents the thermal power of the battery after the static phase, P env_2 represents the thermal power of the battery in the static process and the environment convective exchange.

[0087] P all_2 , P evn_2 may be represented as follows, respectively:

[0088]

[0089] Wherein, t2 represents the static duration.

[0090] According to the discharge test and the ambient temperature T0 (such as-40℃ above) in the static test process, the discharge current I (such as 0.5C above), and the battery temperature T1 at the end of discharge, the discharge duration t1, the static duration t2, combined with the above formula (1)-(7), the equivalent battery self-heating power coefficient K and the environmental heat dissipation coefficient Ku under the ambient temperature T0 and the charge / discharge current I can be obtained.

[0091] By changing different ambient temperature, different charge / discharge current, more equivalent battery self-heating power coefficient K and environmental heat dissipation coefficient Ku under different environment are obtained; then all the equivalent battery self-heating power coefficient K and the environmental heat dissipation coefficient Ku are fitted respectively, and the final equivalent battery self-heating power coefficient K and the environmental heat dissipation coefficient Ku are obtained.

[0092] S2012: according to the model parameters (equivalent battery self-heating power coefficient K and environmental heat dissipation coefficient Ku) of the battery obtained in step S2011, a battery self-heating temperature prediction model is established,

[0093] The battery self-heating temperature prediction model is a model for predicting the future temperature of the battery based on the self-driven heating of the battery.

[0094]

[0095] Wherein, the equivalent battery self-heating power coefficient K and the environmental heat dissipation coefficient Ku are model parameters obtained in step S2011; the mass m, the specific heat capacity c and the thermal equivalent resistance R of the battery can be measured by experiment or provided by the battery manufacturer; Pavg represents the average thermal power in the battery discharge phase; P heat represents the heating thermal power of the external heat source, which is obtained according to the design parameters of the external heat source and can be provided by the manufacturer; P env represents the thermal power of the battery convective exchange with the environment during the charge-discharge process. T end represents the temperature at the end of the battery discharge; T begin represents the temperature at the beginning of the battery discharge; T t represents the real-time temperature during the battery discharge process; T env represents the ambient temperature, which is usually not detected alone, but the battery temperature at the time of power-on after the battery is left for a long enough time.

[0096] S202: Obtain the dischargeable capacity of the battery under different currents, different battery temperatures, and different battery SOCs to form a dischargeable capacity table.

[0097] The experimental test method includes:

[0098] Preparation: Select appropriate battery test equipment, such as a battery charge-discharge tester, which has the functions of accurately controlling the charge-discharge current, voltage, and recording data. At the same time, prepare an environment test box that can accurately control the temperature, such as a high-low temperature test box, to simulate different temperature conditions.

[0099] Set initial SOC: Place the battery in the environmental test box, set to the target temperature and stabilize for a period of time to ensure that the battery temperature is consistent with the ambient temperature. Charge or discharge the battery to the required initial SOC state through the charge-discharge tester.

[0100] Discharge test under different currents: Set the discharge current of the charge-discharge tester to a target value and start the discharge test. During the discharge process, record the voltage, current, time, and other data of the battery in real time. When the battery voltage reaches the cutoff voltage, stop discharging. Calculate the discharge capacity under this condition according to the discharge current and discharge time (discharge capacity = discharge current × discharge time).

[0101] Change parameters and repeat the test: Change the charge-discharge current and repeat the above steps to obtain the discharge capacity data under different discharge currents. Then, change the temperature of the environmental test box and repeat the above steps of setting the initial SOC and discharging under different currents to obtain the discharge capacity data under different temperatures. Finally, change the initial SOC and repeat the test again to obtain the discharge capacity data under different SOCs.

[0102] Under a specific current I k The dischargeable capacity table C under a specific current I

[0103]

[0104] C i,j,k represents the dischargeable capacity under the battery temperature T i , the battery SOC SOC j , and the current I k .

[0105] S203: Combine the battery self-heating temperature prediction model of step S201 and the dischargeable capacity table of step S202 to perform discharge self-heating simulation of the battery, and form an energy yield table of the battery.

[0106] The simulation is performed by a simulation tool simulink, and the process of the simulation is: inputting the initial SOC of the battery, the discharge current, and the initial temperature of the battery, and outputting the real-time temperature of the battery, the real-time SOC, and the corresponding running time t.

[0107] According to the running time t, the first electric quantity consumed for heating the battery from the initial temperature to the real-time temperature is determined as: .

[0108] Based on the dischargeable capacity table, the second electric quantity increased by the battery can be obtained according to the discharge current of the battery, the initial SOC, the initial temperature, the real-time temperature, and the real-time SOC.

[0109] Specifically, according to the discharge current of the battery, the initial SOC, and the initial temperature, the dischargeable capacity table is searched to obtain the dischargeable capacity C0; according to the discharge current of the battery, the real-time temperature, and the real-time SOC, the dischargeable capacity table is searched to obtain the dischargeable capacity C1, and the second electric quantity increased ΔQ2 = C1- C0.

[0110] Based on the real-time first electric quantity and the second electric quantity, an energy yield table is formed. When the second electric quantity is greater than the first electric quantity, the energy yield value is a first value, which represents that heating has a positive energy yield; when the second electric quantity is less than the first electric quantity, the energy yield value is a second value, which represents that heating has a negative energy yield.

[0111] The first electric quantity and the second electric quantity are both counted throughout the whole process from the start of discharge to the end of discharge, and the end of discharge specifically refers to that the battery is discharged to a specified cut-off voltage, for example, 2.8V for a lithium-iron battery.

[0112] The energy yield value is directly and intuitively shown as follows:

[0113] For example 1: If there is no self-heating of the battery, when the initial battery temperature is 0℃, the battery SOC is 20%, and the discharge current is 0.5C, the discharge energy at the time when the cut-off voltage is reached is 5kWh. If there is self-heating of the battery, when the initial battery temperature is 0℃, the battery SOC is 20%, and the discharge current is 0.5C, the discharge energy at the time when the cut-off voltage is reached is 6kWh, and the heating power consumption is 2kWh. Therefore, the second electric quantity is the increased discharge electric quantity of the battery, i.e. 1kWh. The first electric quantity is the heating power consumption, i.e. 2kWh. In this case, the second electric quantity is less than the first electric quantity, which indicates that heating is not beneficial, and heating has a negative energy gain.

[0114] For example 2: If there is no self-heating of the battery, when the initial battery temperature is 0℃, the battery SOC is 50%, and the discharge current is 0.5C, the discharge energy at the time when the cut-off voltage is reached is 7kWh. If there is self-heating of the battery, when the initial battery temperature is 0℃, the battery SOC is 50%, and the discharge current is 0.5C, the discharge energy at the time when the cut-off voltage is reached is 10kWh, and the heating power consumption is 2kWh. Therefore, the second electric quantity is the increased discharge electric quantity of the battery, i.e. 3kWh. The first electric quantity is the heating power consumption, i.e. 2kWh. In this case, the second electric quantity is greater than the first electric quantity, which indicates that heating is beneficial, and heating has a positive energy gain.

[0115] In some embodiments, the energy gain table is a truth table, as shown in Figure 9 The horizontal coordinate of the truth table is the battery SOC, the vertical coordinate of the truth table is the battery temperature, and the content of the truth table is the first value and the second value. The first value indicates that heating has a positive gain, and the second value indicates that heating has a negative gain. For example, the first value is 1, and the second value is 0. The value of the intersection of the battery temperature and the battery SOC is the energy gain value corresponding to the battery temperature and the battery SOC. Figure 9 The truth area (blank part) in the truth table indicates the area with the first value (positive energy gain), and the other grid parts indicate the area with the second value (negative energy gain). The energy gain value corresponding to the battery temperature and the battery SOC can be determined by querying the truth table, and whether heating is beneficial can be determined.

[0116] S102: Monitor the battery temperature.

[0117] S103: If the battery temperature is lower than the first temperature threshold and the battery is in a discharge state, obtain the battery SOC.

[0118] S104: Determine the energy gain value based on the battery temperature, the battery SOC, and the energy gain table.

[0119] S105: If the energy gain value is the first value, control the battery to be powered by an external heat source.

[0120] The first temperature threshold is a temperature that will affect the performance of the battery. The first temperature threshold can be set by the user according to the actual situation, or determined according to the performance of the battery, or obtained according to big data statistics, etc. For example, the first temperature threshold can be 10 degrees Celsius.

[0121] The SOC of the battery is the state of charge, which refers to the proportion of the available capacity in the battery to the nominal capacity, that is, the state of charge of the battery.

[0122] In this embodiment, the battery temperature is monitored. When the battery is at low temperature, that is, the battery temperature is lower than the first temperature threshold, if the battery is in a discharging state, for example, the battery is supplying power to the load, the SOC of the battery is obtained, the energy benefit value is determined based on the battery temperature, the SOC of the battery and the energy benefit table, and if the energy benefit value is the first value, the battery is controlled to supply power to the external heat source. First, the battery itself is used to drive the external heat source to realize self-heating of the battery, reduce the user's cost, and improve the performance of the battery. Second, when the energy benefit value is the first value, the battery is controlled to supply power to the external heat source, which ensures that the self-heating of the battery has a positive energy benefit, makes the heating decision more scientific, and effectively utilizes the energy of the battery to improve the use efficiency of the battery.

[0123] In this embodiment, by establishing the battery self-heating model and the dischargeable capacity table, the energy benefit table is formed, which can accurately and conveniently determine whether the battery heating has a benefit, and facilitate the heating control.

[0124] In some embodiments, the battery heating control method further includes step S106:

[0125] S106: If the battery temperature is lower than the first temperature threshold and the battery is in a charging state, the external charging device is controlled to supply power to the external heat source until the battery temperature reaches the first temperature threshold.

[0126] In this embodiment, when the battery is at low temperature, that is, the battery temperature is lower than the first temperature threshold, if the battery is in a charging state, that is, the battery is connected with the external charging device and is charged through the external charging device, the external charging device is controlled to supply power to the external heat source to heat the battery until the battery temperature reaches the first temperature threshold.

[0127] In this embodiment, when the battery is at low temperature and in a charging state, the external charging device is used to supply power to the external heat source for heating, which can improve the battery temperature and improve the performance of the battery without affecting the charging of the battery. In addition, the heat generated during the charging process can be fully utilized.

[0128] In some embodiments, please refer to Figure 8The battery heating control method further includes steps S301-S304.

[0129] S301: If the battery temperature is lower than the first temperature threshold, in response to receiving a user instruction, determining a heating start time of the external heat source according to the user instruction.

[0130] The user instruction is used for scheduling operation, and the user instruction includes at least one of scheduled discharging, scheduled charging and scheduled heating. The scheduled discharging instruction is used for scheduling the battery to discharge, for example, scheduling the battery to supply power to a load; the scheduled charging instruction is used for scheduling the battery to charge, for example, scheduling an external charging device to supply power to the battery so as to charge the battery; and the scheduled heating instruction is used for scheduling the battery to heat, for example, scheduling to heat after three hours or to heat now, etc. In some embodiments, the user instruction can include information such as a scheduled start time and a scheduled duration.

[0131] In some embodiments, if the heating start time is included in the user instruction, the heating start time is determined as the time selected by the user. For example, the user instruction is to heat now or to heat after two hours or to heat at 5 pm on Wednesday, etc., and the heating start time is the current time or after two hours or at 5 pm on Wednesday.

[0132] In some embodiments, if the scheduled operation start time is included in the user instruction, the heating start time is determined according to the scheduled operation start time. For example, the scheduled operation start time and the current battery temperature can be combined to calculate the heating start time according to an empirical formula. The empirical formula can be obtained by summarizing the past heating rate or calculated according to big data, etc. The heating start time is obtained by reserving the heating time required before the scheduled operation start time according to the empirical formula to calculate the time required for the current battery temperature to rise to the ideal temperature, i.e., the first temperature threshold. For example, the user instruction is to schedule to charge after three hours, the current battery temperature is 0℃, the average heating rate is 10℃ per hour according to the past heating process, and the first temperature threshold is 10℃. Therefore, the heating needs to be started one hour in advance, i.e., after two hours. In some embodiments, since the battery may continue to cool down, the influence of the ambient temperature on the battery temperature needs to be considered when calculating the heating start time.

[0133] In this embodiment, if the battery is heated at the heating start time, the battery temperature has been heated to the ideal temperature when the user scheduled operation starts. Therefore, the user scheduled operation can be better completed, the battery performance is improved, and repeated heating when the battery is not needed can be reduced, thereby reducing resource waste and improving benefits.

[0134] S302: Obtain the first state of the battery when the heating start time is reached.

[0135] The first state of the battery includes a static state, a charging state and a discharging state. The static state means that the battery is not currently working and is in a static waiting state. The charging state means that the battery is being charged. The discharging state means that the battery is being discharged.

[0136] S303: If the first state of the battery is a static state and the SOC of the battery is greater than or equal to the first power threshold, the battery is controlled to supply power to the external heat source.

[0137] If the first state of the battery is a static state and the SOC of the battery is greater than or equal to the first power threshold, the battery is controlled to supply power to the external heat source, and the external heat source heats the battery. For example, the first power threshold can be a power value at which the battery is easily overcharged. For example, the first power threshold can be 95% power. If the SOC of the battery is too high, the battery can be overcharged when supplied with power by an external charging device, which can affect the performance of the battery. Therefore, when the SOC of the battery is greater than or equal to the first power threshold, the battery is first controlled to supply power to the external heat source to consume part of the power. When the SOC of the battery is less than the first power threshold, if the requirement is met, the external charging device can be switched to charge, which can effectively reduce the occurrence of overcharging.

[0138] S304: When the SOC of the battery is less than the first power threshold, if the external charging device is in an allowed charging state, the external charging device is controlled to supply power to the external heat source until the temperature of the battery reaches the first temperature threshold.

[0139] When the battery supplies power to the external heat source until the SOC of the battery is less than the first power threshold, if the external charging device connected to the battery is in an allowed charging state, the external charging device is controlled to supply power to the external heat source, and the external heat source heats the battery until the temperature of the battery reaches the first temperature threshold.

[0140] In this embodiment, when the battery is at a low temperature, the heating start time is determined by receiving a user instruction, and the state of the battery and the SOC of the battery are obtained. In the static state, if the SOC of the battery is too high, the battery is first controlled to supply power to the external heat source for heating until the SOC of the battery is less than the first power threshold. If the external charging device is in an allowed charging state, the external charging device is controlled to supply power to the external heat source for heating. This method can realize early heating, so that the battery is at a suitable temperature when the user needs to use the battery, and can prevent overcharging caused by charging and heating, can protect the battery, improve the performance of the battery and improve the user experience.

[0141] In some embodiments, the battery heating control method further includes steps S305-S306:

[0142] S305: If the first state of the battery is the static state and the SOC of the battery is less than the first power threshold, when the external charging device is in the allowed charging state, the external charging device is controlled to supply power to the external heat source until the temperature of the battery reaches the first temperature threshold.

[0143] S306: When the external charging device is in the disallowed charging state, the battery is controlled to supply power to the external heat source until the temperature of the battery reaches the first temperature threshold.

[0144] In this embodiment, if the first state of the battery is the static state and the SOC of the battery is less than the first power threshold, the state of the external charging device is obtained, if the external charging device is in the allowed charging state, the external charging device is controlled to supply power to the external heat source, and the external heat source heats the battery until the temperature of the battery reaches the first temperature threshold. If the external charging device is in the disallowed charging state, the battery is controlled to supply power to the external heat source until the temperature of the battery reaches the first temperature threshold. In an example, the disallowed charging state of the external charging device can include that the battery is not connected to the external charging device, the external charging device has no power input, the external charging device is in an offline state, etc.

[0145] In this embodiment, when the first state of the battery is the static state and the SOC of the battery is less than the first power threshold, the way of supplying power to the external heat source is determined by the state of the external charging device. When the state of the external charging device is allowed, the external charging device is preferentially used for power supply, and when the state of the external charging device is disallowed, the battery is used for power supply. The battery power can be preferentially protected, but the battery can also be heated when the external condition is not allowed, and the user demand can be ensured.

[0146] In some embodiments, the battery heating control method further includes steps S307-S308:

[0147] S307: If the first state of the battery is the charging state, the external charging device is controlled to supply power to the external heat source until the temperature of the battery reaches the first temperature threshold.

[0148] S308: If the first state of the battery is the discharging state, the battery is controlled to supply power to the external heat source until the temperature of the battery reaches the first temperature threshold.

[0149] In this embodiment, if the battery is in the charging state after the heating start time is reached, the external charging device is controlled to supply power to the external heat source, and the external heat source heats the battery until the temperature of the battery reaches the first temperature threshold. If the battery is in the discharging state after the heating start time is reached, the battery is controlled to supply power to the external heat source, and the external heat source heats the battery until the temperature of the battery reaches the first temperature threshold.

[0150] In some embodiments, the method further comprises steps S401-S402:

[0151] S401: if the charging current of the external charging device is greater than the required current of the external heat source and the battery is in the allowed charging state, then controlling the external charging device to supply power to both the external heat source and the battery;

[0152] S402: if the charging current of the external charging device is less than the required current of the external heat source and the battery is in the allowed discharging state, then controlling the external charging device and the battery to supply power to the external heat source.

[0153] In this embodiment, if the external charging device supplies power to the external heat source, the charging current of the external charging device is monitored, if the charging current of the external charging device is greater than the required current of the external heat source, i.e. the charging current is too large, the battery state is determined, if the battery is in the allowed charging state, then controlling the external charging device to supply power to both the external heat source and the battery, so that the battery shares the excessive charging current. If the charging current of the external charging device is less than the required current of the external heat source, i.e. the charging current is insufficient, the battery state is determined, if the battery is in the allowed discharging state, then controlling the external charging device and the battery to supply power to the external heat source, so that the battery provides the insufficient charging current. This method can improve the stability of the external charging device supplying power to the external heat source and improve the heating efficiency.

[0154] In some embodiments, if the charging current of the external charging device is greater than the required current of the external heat source and the battery is in the disallowed charging state, then controlling the external charging device to stop supplying power to the external heat source. If the charging current of the external charging device is less than the required current of the external heat source and the battery is in the disallowed discharging state, then controlling the external charging device to stop supplying power to the external heat source.

[0155] In some embodiments, the battery heating control method further comprises step S309:

[0156] S309: if the user instruction further comprises a holding instruction, then after the battery temperature reaches the first temperature threshold, continuing to control the external heat source to heat until the battery temperature reaches a second temperature threshold.

[0157] wherein the second temperature threshold is higher than the first temperature threshold, for example, the second temperature threshold can be the optimal working temperature of the battery, for example, the second temperature threshold can be 20°C.

[0158] In this embodiment, if the user instruction further comprises a holding instruction, then after the battery temperature reaches the first temperature threshold, the battery continues to be heated until the battery temperature reaches the second temperature threshold. The battery can be controlled to heat according to the user's needs, and the battery temperature can be raised to a higher temperature when the user needs it, achieving better performance.

[0159] In some embodiments, the battery heating control method further comprises step S501:

[0160] S501: if the output power of the photovoltaic is greater than or equal to the first power threshold, and the battery temperature is less than the third temperature threshold, then control the photovoltaic to supply power to the external heat source until the battery temperature reaches the third temperature threshold.

[0161] Wherein, the external charging device comprises an energy storage converter and a photovoltaic. The photovoltaic refers to a power generation system that uses the photovoltaic effect of a photovoltaic cell to directly convert solar radiation energy into electrical energy. The photovoltaic uses free solar energy. The first power threshold is the power that can meet the working requirements of the external heat source.

[0162] Wherein, for example, the third temperature threshold can be a better battery working temperature, and the third temperature threshold can be equal to or not equal to the second temperature threshold.

[0163] In this embodiment, since the photovoltaic is a free energy source, in order to fully utilize the free energy source, when the output power of the photovoltaic is greater than or equal to the first power threshold, i.e. the requirement of supplying power to the external heat source can be met, if the battery temperature is less than the third temperature threshold, then control the photovoltaic to supply power to the external heat source until the battery reaches the third temperature threshold, and use the free energy source to raise the battery to a more suitable temperature, so that the battery maintains better performance, realizes full and efficient use of the free energy source, and effectively reduces the cost.

[0164] In some embodiments, the battery heating control method further comprises steps S502-S503:

[0165] S502: monitor the grid electricity price.

[0166] S503: if the grid electricity price is higher than the preset price, and the battery SOC is greater than the second electric quantity threshold, then set the energy storage converter to a state of not allowing charging, to close the battery charging and heating request.

[0167] In this embodiment, since the grid electricity price will fluctuate, when the electricity price is too high, using grid power to heat the battery will result in high cost, therefore, the grid electricity price is monitored, if the grid electricity price is higher than the preset price, and the battery SOC is greater than the second electric quantity threshold, then set the energy storage converter to a state of not allowing charging, to not allow the battery to be heated by the grid. This method can reduce the cost and reduce the high cost that may be generated by heating, but at the same time, the battery SOC is considered, and the battery charging and heating request is closed only when the battery has sufficient electric quantity, so that the heating control is more scientific and reasonable.

[0168] In some embodiments, when the grid price is low, the heating can be performed in advance before the user uses electricity to save cost and meet the user's use demand in combination with the user's electricity use rule.

[0169] To sum up, the battery heating control method provided by the embodiment of the application first, by monitoring the battery temperature, in the case of the battery temperature being lower than the first temperature threshold, the battery itself is used to drive the external heat source to realize self-heating of the battery, reducing the user's cost expenditure. Secondly, the energy income table is obtained, the battery temperature and the battery SOC are combined to calculate the real-time energy income value; when the heating has positive energy income, the battery is controlled to supply power to the external heat source, not only realizing the battery temperature rise and improving the battery performance, but also making the positive gain of the battery available capacity increase exceed the electric energy consumed by the heating system, realizing the positive energy income.

[0170] Another embodiment of the application also provides a non-volatile computer readable storage medium, the computer readable storage medium stores computer executable instructions, when the computer executable instructions are executed by at least one processor, the at least one processor executes the battery heating control method as described in any one of the above embodiments.

[0171] It should be noted that the apparatus embodiments described above are only schematic, wherein the units as described as separate components may or may not be physically separate, and the components as shown as units may or may not be physical units, i.e., may be located in one place, or may be distributed on a plurality of network units. Some or all of the modules can be selected according to actual needs to achieve the purpose of the embodiment scheme.

[0172] Through the description of the above embodiments, those skilled in the art can clearly understand that each embodiment can be realized by means of software and a general hardware platform, and of course can also be realized by hardware. Those skilled in the art can understand that all or part of the processes in the above embodiment methods can be completed by a computer program instructing related hardware, and the program can be stored in a computer readable storage medium, and when the program is executed, the processes of the above embodiments can be included. The storage medium can be a magnetic disc, an optical disc, a read-only memory (ROM) or a random access memory (RAM), etc.

[0173] Finally, it should be noted that: the above examples are only used to illustrate the technical solutions of the present application, but not limited to them; under the idea of the present application, the technical features of the above examples or different examples can also be combined, the steps can be implemented in any order, and there are many other changes of different aspects of the present application as described above, which are not provided in details for simplicity; although the present application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing examples, or make equivalent replacement for part of the technical features; 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 embodiments of the present application.

Claims

1. A battery heating control method, characterized by, The method is applied to a battery management system, and the method comprises: obtaining an energy benefit table of the battery, the energy benefit table representing a correspondence relationship among a battery temperature, a battery SOC and an energy benefit value, the energy benefit value comprising a first value and a second value, the first value representing a positive benefit of heating energy, and the second value representing a negative benefit of heating energy; the method for obtaining the energy benefit table comprises: performing charge / discharge tests and standing tests on the battery at different ambient temperatures, recording test data of the battery, and establishing a battery self-heating temperature prediction model based on the test data; obtaining dischargeable capacities of the battery at different currents, different battery temperatures and different battery SOCs to form a dischargeable capacity table; performing a discharge self-heating simulation of the battery according to the battery self-heating temperature prediction model and the dischargeable capacity table to form the energy benefit table of the battery; monitoring a battery temperature; if the battery temperature is lower than a first temperature threshold and the battery is in a discharging state, obtaining a battery SOC; determining an energy benefit value based on the battery temperature, the battery SOC and the energy benefit table; if the energy benefit value is the first value, controlling the battery to supply power to an external heat source; if the battery temperature is lower than the first temperature threshold, determining a heating start time according to a received user instruction in response to the received user instruction, the user instruction comprising at least one of a scheduled discharging, a scheduled charging and a scheduled heating; after the heating start time is reached, obtaining a first state of the battery; if the first state of the battery is a standing state and the battery SOC is greater than or equal to a first power threshold, controlling the battery to supply power to the external heat source; if the first state of the battery is the standing state and the battery SOC is less than the first power threshold, when an external charging device is in a state of allowing charging, controlling the external charging device to supply power to the external heat source until the battery temperature reaches the first temperature threshold, and when the external charging device is in a state of not allowing charging, controlling the battery to supply power to the external heat source until the battery temperature reaches the first temperature threshold.

2. The method of claim 1, wherein, The method further comprises: if the battery temperature is lower than the first temperature threshold and the battery is in a charging state, controlling an external charging device to supply power to an external heat source until the battery temperature reaches the first temperature threshold.

3. The method of claim 1, wherein, The method further comprises: if the first state of the battery is a charging state, controlling the external charging device to supply power to the external heat source until the battery temperature reaches the first temperature threshold; if the first state of the battery is a discharging state, controlling the battery to supply power to the external heat source until the battery temperature reaches the first temperature threshold.

4. The method according to any one of claims 2-3, characterized in that, The control of the external charging device to supply power to the external heat source comprises: if a charging current of the external charging device is greater than a required current of the external heat source and the battery is in a state of allowing charging, controlling the external charging device to supply power to the external heat source and the battery simultaneously; If the charging current of the external charging device is less than the required current of the external heat source, and the battery is in a state allowing discharging, the external charging device and the battery are controlled to supply power to the external heat source simultaneously.

5. The method according to any one of claims 1 to 3, characterized in that, The method further comprises: If the user instruction further comprises a temperature maintaining instruction, after the battery temperature reaches the first temperature threshold, the external heat source continues to be controlled to heat until the battery temperature reaches a second temperature threshold, the second temperature threshold being higher than the first temperature threshold.

6. The method according to any one of claims 1 to 3, characterized in that, The external charging device comprises an energy storage converter and a photovoltaic; The method further comprises: If the output power of the photovoltaic is greater than or equal to a first power threshold, and the battery temperature is less than a third temperature threshold, the photovoltaic is controlled to supply power to the external heat source until the battery temperature reaches the third temperature threshold.

7. The method of claim 6, wherein, The method further comprises: Monitoring a power grid price; If the power grid price is higher than a preset price, and the battery SOC is greater than a second electric quantity threshold, the energy storage converter is set to a state not allowing charging to close a battery charging and heating request.

8. A battery management system comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, The processor executes the computer program to implement the battery heating control method in any one of claims 1 to 7.

9. A non-transitory computer readable storage medium, comprising: The computer readable storage medium stores computer executable instructions, when the computer executable instructions are executed by at least one processor, the at least one processor executes the battery heating control method in any one of claims 1 to 7.

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