Battery heating method, charging device and battery management system

Abstract

The embodiment of the invention provides a battery heating method, a charging device and a battery management system. A power battery can be effectively heated. The method is executed by a charging device and comprises the steps that before the charging device charges a power battery, first indication information is received from a control device of the power battery, and the first indication information is used for indicating the charging device to heat the power battery; and heating the power battery according to the first indication information.

Description

[0001] This application is a divisional application. The application number of the original application is 202280004148.5, and the original application date is March 1, 2022. The entire contents of the original application are incorporated into this application by reference. Technical Field

[0002] The present application relates to the field of battery technology, and in particular to a battery heating method, a charging device and a battery management system. Background Art

[0003] Due to its advantages such as high energy density, rechargeable, safe and environmentally friendly, power batteries are widely used in new energy vehicles, consumer electronics, energy storage systems and other fields.

[0004] However, the use of power batteries in low temperature environments is subject to certain restrictions. For example, the discharge capacity of power batteries in low temperature environments will seriously decline, and the battery cannot be charged in low temperature environments. In order to be able to use the power battery normally, it is necessary to heat the power battery in low temperature environments. How to effectively heat the power battery has become an urgent problem to be solved. Summary of the invention

[0005] The present application provides a battery heating method, a charging device and a battery management system, which can effectively heat a power battery.

[0006] In a first aspect, a battery heating method is provided, which is performed by a charging device, and the method comprises: before the charging device charges the power battery, receiving first indication information from a control device of the power battery, the first indication information being used to instruct the charging device to heat the power battery; and heating the power battery according to the first indication information.

[0007] Charging a power battery at low temperatures may cause lithium deposition and other problems, affecting the safety of the power battery. In the embodiment of the present application, before charging the power battery, if the temperature of the power battery is low, the control device of the power battery will send a first instruction message to the charging device to instruct it to heat the power battery. The charging device receives the first instruction message and heats the power battery based on the first instruction message, thereby avoiding damage to the power battery caused by low-temperature charging.

[0008] In one implementation, the first indication information includes information about the amplitude and / or frequency of a pulse current used to heat the power battery.

[0009] The frequency of the pulse current used when heating different power batteries may be different. The control device of the power battery can determine the information of the amplitude and / or frequency of the pulse current used to heat the power battery, and carry this information of the pulse current in the first indication information, so that the charging device heats the power battery based on the appropriate pulse current to improve the heating performance.

[0010] In one implementation, the charging device includes a bidirectional DC / DC converter, and heating the power battery according to the first indication information includes: controlling the bidirectional DC / DC converter to form a circuit for discharging from the power battery to the charging device, and a circuit for charging from the charging device to the power battery, so as to heat the power battery during the discharging and charging process.

[0011] The bidirectional DC / DC converter includes multiple switching tubes. In this embodiment, the power battery and the charging device can be charged and discharged alternately by controlling each switching tube in the bidirectional DC / DC converter, thereby heating the power battery during the charging and discharging process.

[0012] In one implementation, the charging device further includes an AC / DC converter, and the AC / DC converter and the bidirectional DC / DC converter are connected between an AC power source and the power battery.

[0013] In one implementation, the charging device further includes an energy storage battery, and the bidirectional DC / DC converter is connected between the energy storage battery and the power battery.

[0014] In one implementation, the method further includes: receiving second indication information from the control device, the second indication information being used to instruct the charging device to stop heating the power battery; and stopping heating the power battery according to the second indication information.

[0015] In one implementation, the method further includes: receiving third indication information from the control device, the third indication information being used to instruct the charging device to charge the power battery, the third indication information including information on the charging voltage and / or charging current; and charging the power battery according to the third indication information.

[0016] In this embodiment, after the power battery is heated to a predetermined temperature, the control device of the power battery sends a third instruction information to the charging device to instruct it to charge the power battery, and the charging device receives the third instruction information and charges the power battery based on the third instruction information. Since the temperature of the power battery has risen at this time, damage to the power battery caused by low-temperature charging is avoided, thereby ensuring the safety of the power battery.

[0017] In one implementation, the method further includes: receiving fourth indication information from the control device, the fourth indication information being used to instruct the charging device to stop charging the power battery; and stopping charging the power battery according to the fourth indication information.

[0018] In a second aspect, a battery heating method is provided, which is executed by a battery management system BMS of a power battery, and the method includes: obtaining the temperature of the power battery before a charging device charges the power battery; if the temperature of the power battery is lower than a temperature threshold, sending first indication information to the charging device, wherein the first indication information is used to instruct the charging device to heat the power battery.

[0019] Charging a power battery at low temperatures may cause lithium deposition and other problems, affecting the safety of the power battery. In the embodiment of the present application, before charging the power battery, if the temperature of the power battery is low, the BMS will send a first instruction message to the charging device to instruct it to heat the power battery. The charging device receives the first instruction message and heats the power battery based on the first instruction message, thereby avoiding damage to the power battery caused by low-temperature charging.

[0020] In one implementation, the first indication information includes information about the amplitude and / or frequency of a pulse current used to heat the power battery.

[0021] The frequency of the pulse current used when heating different power batteries may be different. The BMS can determine the amplitude and / or frequency information of the pulse current used to heat the power battery, and carry the pulse current information in the first indication information, so that the charging device heats the power battery based on the appropriate pulse current to improve the heating performance.

[0022] In one implementation, before sending the first indication information to the charging device, the method further includes: determining the maximum amplitude of the pulse current as an amplitude corresponding to the temperature of the power battery based on a correspondence between multiple preset temperatures and multiple amplitudes; and / or determining the frequency of the pulse current as a frequency corresponding to the temperature of the power battery based on a correspondence between multiple preset temperatures and multiple frequencies.

[0023] Based on the current temperature of the power battery, the BMS can determine information such as the maximum amplitude and / or frequency of the pulse current corresponding to the current temperature by looking up a table or the like, which is simple and accurate.

[0024] In one implementation, the method further includes: when the temperature of the power battery is greater than or equal to the temperature threshold, sending second indication information to the charging device, wherein the second indication information is used to instruct the charging device to stop heating the power battery.

[0025] During the heating process, information such as the frequency and / or maximum amplitude of the pulse current can be adjusted accordingly based on the increase in the temperature of the power battery. The BMS can send the first indication information to the charging device multiple times to update the information of the pulse current. A temperature threshold is set. When the power battery is heated to exceed the temperature threshold, the BMS sends the second indication information to the charging device to instruct it to stop heating. The charging device receives the second indication information and stops heating the power battery based on the second indication information.

[0026] In one implementation, the method further includes: sending third indication information to the charging device, where the third indication information is used to instruct the charging device to charge the power battery, and the third indication information includes information of a charging voltage and / or a charging current.

[0027] In this embodiment, after the power battery is heated to a predetermined temperature, the BMS will send a third instruction message to the charging device to instruct it to charge the power battery. The third instruction message may include information on the charging voltage and / or the charging current. The charging device receives the third instruction message and charges the power battery based on the third instruction message. Since the temperature of the power battery has risen at this time, the safety of the power battery is guaranteed and damage to the power battery is avoided.

[0028] In one implementation, the method further includes: sending fourth indication information to the charging device, where the fourth indication information is used to instruct the charging device to stop charging the power battery.

[0029] In a third aspect, a charging device is provided, comprising: a receiving module, used to receive first indication information sent by a battery management system BMS of the power battery before the charging device charges the power battery, wherein the first indication information is used to instruct the charging device to heat the power battery; and a processing module, used to heat the power battery according to the first indication information.

[0030] In one implementation, the first indication information includes information about the amplitude and / or frequency of a pulse current used to heat the power battery.

[0031] In one implementation, the charging device also includes a bidirectional DC / DC converter, and the processing module is specifically used to control the bidirectional DC / DC converter to form a circuit for discharging from the power battery to the charging device, and a circuit for charging from the charging device to the power battery, so as to heat the power battery during the discharging and charging process.

[0032] In one implementation, the charging device further includes an AC / DC converter, and the AC / DC converter and the bidirectional DC / DC converter are connected between an AC power source and the power battery.

[0033] In one implementation, the charging device further includes an energy storage battery, and the bidirectional DC / DC converter is connected between the energy storage battery and the power battery.

[0034] In one implementation, the receiving module is further used to: receive second indication information sent by the BMS, where the second indication information is used to instruct the charging device to stop heating the power battery; the processing module is further used to: stop heating the power battery according to the second indication information.

[0035] In one implementation, the receiving module is further used to: receive third indication information sent by the BMS, the third indication information is used to instruct the charging device to charge the power battery, and the third indication information includes information on the charging voltage and / or charging current; the processing module is further used to: charge the power battery according to the third indication information.

[0036] In one implementation, the receiving module is further used to: receive fourth indication information sent by the BMS, wherein the fourth indication information is used to instruct the charging device to stop charging the power battery; the processing module is further used to: stop charging the power battery according to the fourth indication information.

[0037] In a fourth aspect, a BMS is provided, comprising: a processing module, used to obtain the temperature of the power battery before the charging device charges the power battery; a sending module, used to send first indication information to the charging device when the temperature of the power battery is less than a temperature threshold, the first indication information being used to instruct the charging device to heat the power battery.

[0038] In one implementation, the first indication information includes information about the amplitude and / or frequency of a pulse current used to heat the power battery.

[0039] In one implementation, before sending the first indication information to the charging device, the processing module is also used to: determine the maximum amplitude of the pulse current as an amplitude corresponding to the temperature of the power battery based on a correspondence between multiple preset temperatures and multiple amplitudes; and / or determine the frequency of the pulse current as a frequency corresponding to the temperature of the power battery based on a correspondence between multiple preset temperatures and multiple frequencies.

[0040] In one implementation, the sending module is further used to: when the temperature of the power battery is greater than or equal to the temperature threshold, send second indication information to the charging device, wherein the second indication information is used to instruct the charging device to stop heating the power battery.

[0041] In one implementation, the sending module is further used to: send third indication information to the charging device, where the third indication information is used to instruct the charging device to charge the power battery, and the third indication information includes information on the charging voltage and / or charging current.

[0042] In one implementation, the sending module is further used to: send fourth indication information to the charging device, where the fourth indication information is used to instruct the charging device to stop charging the power battery.

[0043] In a fifth aspect, a battery heating device is provided, comprising a memory and a processor, wherein the memory is used to store instructions, and the processor is used to read the instructions and execute the battery heating method described in the first aspect or any implementation of the first aspect based on the instructions.

[0044] In a sixth aspect, a computer storage medium is provided, comprising instructions for causing a computer to execute the battery heating method described in the first aspect or any implementation of the first aspect, or the battery heating method described in the second aspect or any implementation of the second aspect. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments of the present application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the drawings without paying creative work.

[0046] Figure 1 It is a schematic diagram of an application scenario of the battery heating device of an embodiment of the present application.

[0047] Figure 2 It is a schematic diagram of an application scenario of the battery heating device of an embodiment of the present application.

[0048] Figure 3 It is a flow chart of the battery heating method according to an embodiment of the present application.

[0049] Figure 4 It is a flow chart of a battery heating method according to another embodiment of the present application.

[0050] Figure 5 It is a schematic block diagram of a charging device according to an embodiment of the present application.

[0051] Figure 6 It is a schematic block diagram of the BMS of an embodiment of the present application.

[0052] Figure 7 It is a schematic block diagram of a charging device according to an embodiment of the present application.

[0053] Figure 8 It is a schematic block diagram of the BMS of an embodiment of the present application.

[0054] Fig. 9 is a schematic block diagram of a battery heating device according to an embodiment of the present application.

[0055] Fig.10 It is a schematic block diagram of a computer storage medium according to an embodiment of the present application.

[0056] In the drawings, the drawings are not drawn to scale. DETAILED DESCRIPTION

[0057] The following detailed description and drawings of the embodiments of the present application are used to illustrate the principles of the present application, but cannot be used to limit the scope of the present application, that is, the present application is not limited to the described embodiments.

[0058] In the description of the present application, it should be noted that, unless otherwise specified, "multiple" means more than two; the terms "upper", "lower", "left", "right", "inside", "outside", etc., indicating the orientation or positional relationship, are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first", "second", "third", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance. "Vertical" is not strictly vertical, but is within the allowable error range. "Parallel" is not strictly parallel, but is within the allowable error range.

[0059] The directional words appearing in the following description are all directions shown in the figures, and do not limit the specific structure of this application. In the description of this application, it should also be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected or indirectly connected through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to the specific circumstances.

[0060] With the development of the times, new energy vehicles have huge market prospects due to their environmental protection, low noise, low cost and other advantages. They can effectively promote energy conservation and emission reduction, which is beneficial to the development and progress of society.

[0061] Due to the electrochemical characteristics of power batteries, the charging and discharging capabilities of power batteries are greatly limited in low temperature environments, which seriously affects customers' winter car experience. Therefore, in order to use the power batteries normally, it is necessary to heat the power batteries in low temperature environments.

[0062] The power battery in the embodiment of the present application can be a lithium-ion battery, a lithium metal battery, a lead-acid battery, a nickel-cathode battery, a nickel-metal hydride battery, a lithium-sulfur battery, a lithium-air battery or a sodium-ion battery, etc., which is not limited here. In terms of scale, the power battery in the embodiment of the present application can be a single cell, or a battery module or a battery pack, which is not limited here. In terms of application scenarios, the power battery can be used in power devices such as automobiles and ships. For example, it can be applied to power vehicles to power the motors of power vehicles as a power source for electric vehicles. The power battery can also power other electrical devices in electric vehicles, such as in-car air conditioners, car players, etc.

[0063] For the convenience of description, the application of power batteries to new energy vehicles (i.e., power vehicles, or electric vehicles) will be taken as an example to illustrate the solution of the present application.

[0064] Typically, the power battery can be charged using an AC power source or an energy storage battery. As an example, Figure 1 and Figure 2 A schematic diagram showing possible application scenarios of the embodiments of the present application is shown. Figure 1As shown, the charging device 1 can be, for example, a charging pile, and the charging device 1 includes a bidirectional AC / DC converter 30, a bidirectional DC / DC converter 10, and a controller 20. The charging device 1 can charge a vehicle 50 through an AC power source 40, such as a power grid. Among them, a bidirectional AC / DC converter 30 and a bidirectional DC / DC converter 10 are connected between the AC power source 40 and the vehicle 50. The bidirectional AC / DC converter 30 can convert the AC power output by the AC power source 40 into a DC signal, and the DC signal is then converted into a voltage by the bidirectional DC / DC converter 10, so as to charge the power battery in the vehicle 50. The controller 20 is used to control the bidirectional AC / DC converter 30 and the bidirectional DC / DC converter 10, and can communicate with the battery management system (BMS) in the vehicle 50.

[0065] For example, Figure 2 As shown, the charging device 2 includes an energy storage battery 60 and a bidirectional DC / DC converter 10. The charging device 2 can charge the vehicle 50 through the energy storage battery 60. A bidirectional DC / DC converter 10 is connected between the energy storage battery 60 and the vehicle 50 for converting the voltage of the DC signal output by the energy storage battery 60. The charging device 2 can be, for example, a charging station, such as a photovoltaic storage charging and inspection smart microgrid charging station, etc., wherein the energy storage battery 60 can draw power from a power grid or a photovoltaic panel, etc., through an inverter (Power Conversion System, PCS).

[0066] It should be understood that in some cases, such as when the charging device is only used to charge the power battery, the bidirectional AC / DC converter 30 can also be replaced by a unidirectional AC / DC converter, and the bidirectional DC / DC converter 10 can also be replaced by a unidirectional DC / DC converter.

[0067] In addition to outputting DC current to charge the power battery, the charging device can also be used as a battery heating device to output pulse current to heat the power battery. If the power battery is in a low temperature state, charging the power battery at low temperature may cause problems such as lithium deposition in the battery cell, which in turn causes safety problems.

[0068] To this end, the embodiment of the present application proposes that before charging the power battery, the charging device can be used to heat the power battery at a low temperature. For example, the power battery and the charging device can be alternately charged and discharged by controlling each switch tube in the bidirectional AC / DC converter or the bidirectional DC / DC converter, thereby heating the power battery during the charging and discharging process. Then, the heated power battery is charged by the charging device.

[0069] Figure 3is a schematic flow chart of a battery heating method according to an embodiment of the present application. Figure 3 The method 100 shown is performed by a control device and a charging device of the power battery. The charging device may be, for example, Figure 1 The charging device 1 shown in Figure 2 The charging device 2 shown. The control device of the power battery is used to manage and control the power battery, for example, it can be a BMS of the power battery or a vehicle controller. In the following, the control device is described as a BMS, and the following operations performed by the BMS can also be replaced by those performed by the vehicle controller.

[0070] like Figure 3 As shown, the method 100 includes part or all of the following steps: Step 110 and Step 120 are executed by the BMS, and Step 130 and Step 140 are executed by the charging device.

[0071] In step 110 , before the charging device charges the power battery, the BMS obtains the temperature of the power battery.

[0072] In step 120 , if the temperature of the power battery is lower than the temperature threshold, the BMS sends a first indication message to the charging device.

[0073] The first instruction information is used to instruct the charging device to heat the power battery.

[0074] In step 130 , before charging the power battery, the charging device receives the first indication information sent by the BMS of the power battery.

[0075] In step 140 , the charging device heats the power battery according to the first instruction information.

[0076] Since charging the power battery at low temperature may cause lithium deposition and other problems, affecting the safety of the power battery, in this embodiment, before charging the power battery, if the temperature of the power battery is low, the BMS will send a first instruction message to the charging device to instruct it to heat the power battery, and the charging device receives the first instruction message and heats the power battery based on the first instruction message, thereby avoiding damage to the power battery caused by low-temperature charging.

[0077] In one implementation, Figure 3 As shown, method 100 also includes part or all of steps 150 to 170 .

[0078] In step 150 , when the temperature of the power battery is greater than or equal to the temperature threshold, the BMS sends second instruction information to the charging device, where the second instruction information is used to instruct the charging device to stop heating the power battery.

[0079] In step 160 , the charging device receives the second indication information sent by the BMS.

[0080] The second instruction information is used to instruct the charging device to stop heating the power battery.

[0081] In step 170 , the charging device stops heating the power battery according to the second instruction information.

[0082] The heating of the power battery by the charging device is based on the discharge and charging of the power battery. The alternation of the discharge process and the charging process forms a pulse current for heating the power battery. For example, the waveform of the pulse current may be a sine wave or a similar waveform thereof.

[0083] In one implementation, the first indication information includes information about a pulse current for heating the power battery, for example, the first indication information includes information about the amplitude and / or frequency of the pulse current. Here, the information about the amplitude of the pulse current may include the maximum amplitude or average amplitude of the pulse current.

[0084] The frequency of the pulse current used to heat different power batteries can be different. Generally, the heating effect of a high-frequency pulse signal is worse than that of a low-frequency pulse signal, but a high-frequency pulse signal causes less damage to the battery cell. For example, when the temperature of the power battery is low, only a high-frequency pulse current can be used to heat the power battery; when the temperature of the power battery is high, a low-frequency or high-frequency pulse current can be used to heat the power battery. For another example, for power batteries on different models, the battery cells have different tolerances, and the frequency of the pulse current required for heating is also different. Therefore, pulse currents of different frequencies may be required for different power batteries.

[0085] The BMS can determine the information of the amplitude and / or frequency of the pulse current used to heat the power battery according to information such as the type and current temperature of the power battery, and carry such information of the pulse current in the first indication information, so that the charging device heats the power battery based on the appropriate pulse current to improve the heating performance. In addition, optionally, when determining the information of the amplitude and / or frequency of the pulse current, the BMS can also consider factors such as the battery state of health (SOH) at the same time.

[0086] During the heating process, the information of the pulse current used to heat the power battery can be adjusted accordingly based on the increase in the temperature of the power battery. For example, the BMS can obtain the temperature of the power battery at certain time intervals, and update the pulse current information based on the temperature change of the power battery, and when the pulse current information needs to be updated, the BMS sends the first indication information carrying the updated pulse current information to the charging device.

[0087] A temperature threshold can be set. After the power battery and the charging device establish a physical connection and the handshake is successful, if the temperature of the power battery is lower than the temperature threshold, the BMS sends a first indication message to the charging device, and the charging device receives the first indication message and heats the power battery based on the first indication message. During the heating process, the BMS can obtain the temperature of the power battery at a certain time interval until the temperature of the power battery rises to or greater than the temperature threshold. The BMS sends a second indication message to the charging device, and the charging device receives the second indication message and stops heating the power battery based on the second indication message.

[0088] In one implementation, before the BMS sends the first indication information to the charging device, the method 100 further includes: the BMS determines that the maximum amplitude of the pulse current is an amplitude corresponding to the temperature of the power battery based on a correspondence between multiple preset temperatures and multiple amplitudes; and / or determines that the frequency of the pulse current is a frequency corresponding to the temperature of the power battery based on a correspondence between multiple preset temperatures and multiple frequencies.

[0089] Based on the current temperature of the power battery, the BMS can determine information such as the maximum amplitude and / or frequency of the pulse current corresponding to the current temperature by looking up a table or the like, which is simple and accurate.

[0090] For example, taking the influence of the power battery temperature on the pulse current frequency as an example, it is assumed that the corresponding relationship between the power battery temperature and the pulse current frequency is shown in Table 1. In practical applications, for different types of power batteries, the query table may be different. Assume that the temperature threshold is T0, T1<T2<T3<…<Tn≤T0.

[0091] Table 1

[0092] temperature [T1, T2] [T2, T3] [T3, T4] … [Tn-1, Tn] frequency F1 F2 F3 … Fn

[0093] As shown in Table 1, after the power battery and the charging device establish a physical connection and handshake successfully, the BMS first detects the temperature of the power battery to avoid charging the power battery at low temperatures. For example, the BMS can obtain the temperature of the power battery at fixed time intervals. If the detected temperature of the power battery is between T1 and T2, the BMS queries Table 1 and selects frequency F1 as the frequency of the pulse current for heating the power battery, and carries the information of frequency F1 in the first indication information. After receiving the first indication information, the charging device provides a pulse current with a frequency of F1 to the power battery; after the time interval, the temperature of the power battery is obtained. If the detected temperature of the power battery rises to between T2 and T3, the BMS queries Table 1 and selects frequency F2 as the frequency of the pulse current for heating the power battery, and carries the information of frequency F2 in the first indication information. After receiving the first indication information, the charging device provides a pulse current with a frequency of F2 to the power battery; in sequence, until the temperature of the power battery is heated to greater than Tn, the BMS sends a second indication information to the charging device, and when the charging device receives the second indication information, it stops heating the power battery according to the second indication information.

[0094] It should be understood that in the embodiment of the present application, optionally, the BMS sends a first indication message to the charging device, and the first indication message can be used to instruct the charging device to charge the power battery, and the first indication message carries information about the temperature of the power battery. After the charging device receives the first indication message sent by the BMS, it determines whether the power battery needs to be heated according to the temperature of the power battery. For example, if the charging device determines that the temperature of the power battery is less than the temperature threshold, the charging device heats the power battery before charging the power battery.

[0095] Further, optionally, the BMS may send the temperature of the power battery to the charging device, and the charging device may determine information such as the maximum amplitude and / or frequency of the pulse current corresponding to the current temperature based on the current temperature of the power battery by the above-mentioned table lookup or other methods.

[0096] In one implementation, Figure 4 As shown, method 100 may further include steps 181 to 183 .

[0097] In step 181 , the BMS sends third instruction information to the charging device.

[0098] The third indication information is used to instruct the charging device to charge the power battery.

[0099] The third indication information may include, for example, charging parameters, such as information on charging voltage and / or charging current.

[0100] In step 182 , the charging device receives the third indication information sent by the BMS.

[0101] In step 183, the charging device charges the power battery according to the third instruction information.

[0102] After the power battery is heated to a predetermined temperature, the BMS will send a third instruction message to the charging device to instruct it to charge the power battery. The charging device receives the third instruction message and charges the power battery based on the third instruction message. Since the temperature of the power battery has risen at this time, the damage to the power battery caused by low-temperature charging is avoided, thus ensuring the safety of the power battery.

[0103] Of course, after the power battery establishes a physical connection with the charging device and the handshake is successful, if the temperature of the power battery is already greater than the temperature threshold, the BMS may not send the first indication information to the charging device, but may send the third indication information to the charging device. The charging device receives the third indication information and charges the power battery according to the third indication information.

[0104] In one implementation, Figure 4 As shown, method 100 also includes steps 191 to 193 .

[0105] In step 191 , the BMS sends fourth instruction information to the charging device, where the fourth instruction information is used to instruct the charging device to stop charging the power battery.

[0106] In step 192, the charging device receives fourth instruction information sent by the BMS, where the fourth instruction information is used to instruct the charging device to stop charging the power battery.

[0107] In step 193, the charging device stops charging the power battery according to the fourth instruction information.

[0108] In this way, after the power battery is charged, the BMS instructs the charging device to stop charging the power battery by sending fourth instruction information to the charging device.

[0109] Figure 5 A possible specific implementation of the above-mentioned battery heating method 100 is shown. Figure 5 As shown, the process of heating and charging the power battery may include some or all of the following steps.

[0110] In step 101, a physical connection is established between the power battery and the charging device.

[0111] In step 102, the low voltage auxiliary power supply is powered on.

[0112] In step 103 , the BMS and the charging device, such as the controller 20 , conduct a handshake to establish a communication connection.

[0113] For specific details of steps 101 to 103 and steps 111 to 113, for example, reference may be made to the details of the charging process in the GB / T27930-2015 standard.

[0114] Steps 104 to 110 in the dashed box are a possible specific implementation of the above-mentioned battery heating method 100 , and steps 104 to 110 are new contents that need to be added to the existing standards.

[0115] In step 104 , the BMS obtains the temperature T of the power battery and compares the temperature T with a temperature threshold T0 .

[0116] If T<T0, then execute step 105 to step 110, and the charging device heats the power battery; otherwise, when T≥T0, directly execute step 111 to step 113, and the charging device charges the power battery.

[0117] In step 105 , the BMS determines the maximum amplitude and frequency of the pulse current for heating the power battery.

[0118] The BMS may determine the maximum amplitude and / or frequency of the pulse current that matches the power battery by, for example, looking up a table.

[0119] In step 106 , the BMS sends first indication information to the charging device.

[0120] The first indication information may carry information about the maximum amplitude and frequency of the pulse current, for example.

[0121] In step 107 , the charging device receives the first instruction information, and heats the power battery based on the first instruction information.

[0122] The amplitude and frequency of the pulse current during the power battery heating process may be determined based on the information of the maximum amplitude and frequency of the pulse current carried in the first indication information.

[0123] In step 108 , during the heating process, the BMS compares T with a temperature threshold T0 .

[0124] If T<T0, steps 105 to 107 are repeated, and the charging device heats the power battery; otherwise, when T≥T0, steps 109 and 110 are executed.

[0125] In step 109 , the BMS sends second indication information to the charging device.

[0126] In step 110 , the charging device receives the second instruction information, and stops heating the power battery based on the second instruction information.

[0127] Next, after step 110 , steps 111 to 113 are executed.

[0128] In step 111, charging parameters are configured.

[0129] For example, the BMS may transmit information of charging parameters such as charging voltage and charging current to the charging device.

[0130] In step 112 , the charging device charges the power battery based on the charging parameters.

[0131] In step 113 , charging ends.

[0132] It can be seen that in the embodiment of the present application, after a physical connection is established between the power battery and the charging device and a handshake is successful, the BMS of the power battery determines the current temperature of the power battery, and heats the power battery first when the temperature is low, and then charges the power battery after the temperature of the power battery rises, thereby avoiding damage to the power battery caused by low-temperature charging and improving the safety of the power battery.

[0133] The embodiment of the present application does not limit how the charging device charges the power battery. As an example, in one implementation, the charging device may include a bidirectional DC / DC converter. In step 140, according to the first indication information, the power battery is heated, including: controlling the bidirectional DC / DC converter to form a circuit for discharging from the power battery to the charging device, and a circuit for charging from the charging device to the power battery, so as to heat the power battery during the discharging and charging process.

[0134] The bidirectional DC / DC converter includes multiple switching tubes. By controlling each switching tube in the bidirectional DC / DC converter, the power battery and the charging device are charged and discharged alternately, so that the power battery can be heated during the charging and discharging process.

[0135] Below Figure 6 Taking the DC / DC converter shown in the figure as an example, it is described how the charging device heats the power battery. Figure 6 Taking the DC / DC converter with dual active bridge (DAB) architecture as an example, the switch tube is controlled according to the timing, and a circuit for discharging from the power battery to the charging device and a circuit for charging from the charging device to the power battery can be alternately formed, thereby heating the power battery during the discharge and charging process. In practical applications, DC / DC converters with LLC, CLLC, CF-DAB, partial-power converter and other architectures can also be used.

[0136] As an example, Figure 6In the bidirectional DC / DC converter 10 shown, each bridge arm in the bidirectional DC / DC converter 10 includes two switch tubes connected in series, namely, a bridge arm formed by switch tube Q1 and switch tube Q2, a bridge arm formed by switch tube Q3 and switch tube Q4, a bridge arm formed by switch tube Q5 and switch tube Q6, and a bridge arm formed by switch tube Q7 and switch tube Q8.

[0137] Without considering the dead time, the upper and lower switches of each bridge arm are 180° complementary conduction, and the diagonal switches are turned on at the same time. Assume that the switching period is T, the switching frequency fs = 1 / T, V1 and V2 are the input voltage and output voltage, where the V1 side is the side connected to the AC / DC converter or energy storage battery, and the V2 side is the side connected to the power battery. AB for Figure 6 The voltage between point A and point B, V CD for Figure 6 The voltage between point C and point D. L is the inductor current, v L is the inductor voltage. By controlling V AB With V CD The angle between the two phases is the phase shift angle to control the transmission power of the bidirectional DC / DC converter 10. The ratio of the phase shift angle to π is the phase shift duty cycle.

[0138] When the bidirectional DC / DC converter 10 is working in the forward direction, the driving signal waveforms of the switch tubes Q1 and Q4, Q2 and Q3 are ahead of the switch tubes Q5 and Q8, Q6 and Q7 respectively. When working in reverse, the driving signal waveforms of switch tubes Q1 and Q4, Q2 and Q3 lag behind switch tubes Q5 and Q8, Q6 and Q7 respectively. The reverse operation of the bidirectional DC / DC converter 10 is similar to the forward operation. The forward operation is taken as an example to describe the charging and discharging process between the bidirectional DC / DC converter 10 and the power battery.

[0139] In a switching cycle, for switch state 1 (before time t0), before time t0, switch tubes Q2, Q3, Q6, and Q7 are turned on, and the inductor current i L is negative, the current passes through the switch tubes Q2, Q3, Q6 and Q7, and the power flows from the V1 side to the V2 side.

[0140] For switch state 2 (from t0 to t1), at t0, all the switches on the V1 side are turned off, and the switches Q6 and Q7 on the V2 side are turned on. Because the inductor current cannot change suddenly, the inductor current i LIt is still negative, and the inductor current charges the parasitic capacitors C2 and C3, while the capacitors C1 and C4 discharge. At t1, the voltage across the capacitors C2 and C3 reaches V1, and the voltage across the capacitors C1 and C4 is zero, and the anti-parallel diodes D1 and D4 are naturally turned on.

[0141] For switch state 3 (from t1 to t2), at t1, the switch tubes Q1 and Q4 are turned on. Since the anti-parallel diodes D1 and D4 of the switch tubes Q1 and Q4 are turned on at t1, the voltage across the switch tubes Q1 and Q4 is zero when they are turned on, achieving zero voltage conduction. At this time, the inductor current i L It is a negative value, the V1 side absorbs power, the V2 side absorbs power, the energy stored in the inductor is transmitted to the V1 side and the V2 side, and there is power reflux on the V1 side.

[0142] For switching state 4 (from t2 to t3), starting from t2, due to the action of power supply V1, the inductor current begins to become positive and flows through switch tubes Q1, Q4, Q6 and Q7. In switching state 4, both the V1 side and the V2 side store energy in the inductor. Because power flows from the V2 side to the inductor, there is power reflux on the V2 side.

[0143] For switch state 5 (from t3 to t4), switch tubes Q6 and Q7 are disconnected, and the current charges capacitors C6 and C7, while capacitors C5 and C8 are discharged. At t4, the voltage across capacitors C6 and C7 reaches V2, the voltage across capacitors C5 and C8 is zero, and anti-parallel diodes D5 and D8 are naturally turned on.

[0144] For switch state 6 (from t4 to t5), at t4, switch tubes Q5 and Q8 are turned on. Since the anti-parallel diodes D5 and D8 of switch tubes Q5 and Q8 are turned on at this time, the voltage across D5 and D8 is zero when they are turned on, achieving zero voltage conduction. In switch state 6, V1 side emits power and V2 side absorbs power.

[0145] After time t5, the bidirectional DC / DC converter 10 starts working in another half switching cycle. The specific process is similar to the above and will not be repeated here.

[0146] It can be seen that in the bidirectional DC / DC converter 10, by discharging the power battery to the inductor and charging the inductor to the power battery, the power battery can be heated in the alternating process of charging and discharging.

[0147] Furthermore, the charging device may also include an AC / DC converter, such as Figure 1The bidirectional AC / DC converter 30 shown in FIG. The AC / DC converter and the bidirectional DC / DC converter are connected between the AC power source and the power battery.

[0148] Alternatively, the charging device may also include an energy storage battery, e.g. Figure 2 The energy storage battery 60 shown in FIG. A bidirectional DC / DC converter is connected between the energy storage battery and the power battery.

[0149] The present application also provides a charging device 200. Figure 7 As shown, the charging device 200 includes:

[0150] The receiving module 210 is used to receive first instruction information sent by the battery management system BMS of the power battery before the charging device 200 charges the power battery, and the first instruction information is used to instruct the charging device 200 to heat the power battery;

[0151] The processing module 220 is configured to heat the power battery according to the first indication information.

[0152] In one implementation, the first indication information includes information about the amplitude and / or frequency of the pulse current used to heat the power battery.

[0153] In one implementation, the charging device 200 also includes a bidirectional DC / DC converter, and the processing module 220 is specifically used to control the bidirectional DC / DC converter to form a circuit for discharging from the power battery to the charging device 200, and a circuit for charging from the charging device 200 to the power battery, so as to heat the power battery during the discharge and charging process.

[0154] In one implementation, the charging device 200 further includes an AC / DC converter, and the AC / DC converter and the bidirectional DC / DC converter are connected between the AC power source and the power battery.

[0155] In one implementation, the charging device 200 further includes an energy storage battery, and a bidirectional DC / DC converter is connected between the energy storage battery and the power battery.

[0156] In one implementation, the receiving module 210 is further used to: receive second indication information sent by the BMS, where the second indication information is used to instruct the charging device 200 to stop heating the power battery; the processing module 220 is further used to: stop heating the power battery according to the second indication information.

[0157] In one implementation, the receiving module 210 is further used to: receive third indication information sent by the BMS, where the third indication information is used to instruct the charging device 200 to charge the power battery, and the third indication information includes information on the charging voltage and / or charging current; the processing module 220 is further used to: charge the power battery according to the third indication information.

[0158] In one implementation, the receiving module 210 is further used to: receive fourth indication information sent by the BMS, where the fourth indication information is used to instruct the charging device 200 to stop charging the power battery; the processing module 220 is further used to: stop charging the power battery according to the fourth indication information.

[0159] It should be understood that the specific details of the charging device 200 can refer to the above description of the charging device in the method 100, and for the sake of brevity, they are not repeated here.

[0160] The present application also provides a BMS, such as Figure 8 As shown, the BMS 300 includes:

[0161] The processing module 310 is used to obtain the temperature of the power battery before the charging device charges the power battery;

[0162] The sending module 320 is used to send first instruction information to the charging device when the temperature of the power battery is lower than the temperature threshold, where the first instruction information is used to instruct the charging device to heat the power battery.

[0163] In one implementation, the first indication information includes information about the amplitude and / or frequency of the pulse current used to heat the power battery.

[0164] In one implementation, before sending the first indication information to the charging device, the processing module 310 is also used to: determine the maximum amplitude of the pulse current as an amplitude corresponding to the temperature of the power battery based on the correspondence between multiple preset temperatures and multiple amplitudes; and / or, determine the frequency of the pulse current as a frequency corresponding to the temperature of the power battery based on the correspondence between multiple preset temperatures and multiple frequencies.

[0165] In one implementation, the sending module 320 is further used to: when the temperature of the power battery is greater than or equal to a temperature threshold, send second indication information to the charging device, where the second indication information is used to instruct the charging device to stop heating the power battery.

[0166] In one implementation, the sending module 320 is further used to: send third indication information to the charging device, where the third indication information is used to instruct the charging device to charge the power battery, and the third indication information includes information of the charging voltage and / or the charging current.

[0167] In one implementation, the sending module 320 is further used to: send fourth instruction information to the charging device, where the fourth instruction information is used to instruct the charging device to stop charging the power battery.

[0168] It should be understood that the specific details of the BMS 300 may refer to the aforementioned description of the method 100 for the BMS, and for the sake of brevity, they are not repeated here.

[0169] Fig. 9 FIG. 2 shows a schematic block diagram of a battery heating device according to another embodiment of the present application. Fig. 9 As shown, the battery heater 400 includes a memory 410 and a processor 420, the memory 410 is used to store instructions, the processor 420 is used to read the instructions, and based on the instructions, execute the operations performed by the charging device or the control device of the power battery in the battery heating method 100 in each embodiment of the present application.

[0170] Fig.10 FIG. 1 is a schematic block diagram of a computer storage medium according to another embodiment of the present application. Fig.10 As shown, the computer storage medium 500 includes instructions 510, and the instructions 510 are used to enable the computer to execute the operations performed by the charging device or the control device of the power battery in the battery heating method 100 in each embodiment of the present application.

[0171] The present application also provides a power device, including a power battery and a charging device in any of the above embodiments, wherein the charging device is connected to the power battery and is used to heat the power battery before charging the power battery. The power device may be, for example, a power vehicle.

[0172] Those of ordinary skill in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

[0173] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the above method embodiments and will not be repeated here.

[0174] In the several embodiments provided in the present application, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic. For example, the division of the units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0175] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

Claims

1. A method for heating a battery, characterized in that: Executed by a charging device, the method includes: Before the charging device charges the power battery and configures the charging parameters, first instruction information is received from the control device of the power battery, wherein the first instruction information is used to instruct the charging device to heat the power battery, wherein the heating of the power battery by the charging device is based on discharging and charging the power battery, and a pulse current for heating the power battery is alternately formed during the discharging process and the charging process; heating the power battery according to the first indication information; The charging device includes a bidirectional DC / DC converter, and heating the power battery according to the first indication information includes: controlling the bidirectional DC / DC converter to form a circuit for discharging from the power battery to the charging device and a circuit for charging from the charging device to the power battery, so as to heat the power battery during the discharging and charging processes; The first indication information includes information on the amplitude and / or frequency of the pulse current used to heat the power battery; Before sending the first indication information to the charging device, the method further includes: According to the correspondence between the preset multiple temperatures and the multiple amplitudes, determining that the maximum amplitude of the pulse current is an amplitude corresponding to the temperature of the power battery; and / or, According to the preset correspondence relationship between multiple temperatures and multiple frequencies, the frequency of the pulse current is determined to be a frequency corresponding to the temperature of the power battery.

2. The method according to claim 1, characterized in that The configuring charging parameters includes: receiving a charging voltage and a charging current sent by a BMS. Before configuring the charging parameters, the BMS obtains a temperature T of the power battery and compares the temperature T with a temperature threshold T0.

3. The method according to claim 1, characterized in that The charging device further includes an AC / DC converter, and the AC / DC converter and the bidirectional DC / DC converter are connected between an AC power source and the power battery.

4. The method according to claim 1, characterized in that The charging device also includes an energy storage battery, and the bidirectional DC / DC converter is connected between the energy storage battery and the power battery.

5. The method according to claim 1, characterized in that The method further comprises: receiving second instruction information from the control device, where the second instruction information is used to instruct the charging device to stop heating the power battery; According to the second instruction information, heating of the power battery is stopped.

6. The method according to any one of claims 1 to 5, characterized in that The method further comprises: receiving third instruction information from the control device, wherein the third instruction information is used to instruct the charging device to charge the power battery, and the third instruction information includes information of a charging voltage and / or a charging current; The power battery is charged according to the third instruction information.

7. The method according to claim 6, characterized in that The method further comprises: receiving fourth instruction information from the control device, wherein the fourth instruction information is used to instruct the charging device to stop charging the power battery; According to the fourth instruction information, charging of the power battery is stopped.

8. A method for heating a battery, characterized in that: The method is performed by a control device of a power battery, and includes: Before the charging device charges the power battery and configures charging parameters, obtaining the temperature of the power battery; If the temperature of the power battery is lower than the temperature threshold, first instruction information is sent to the charging device, where the first instruction information is used to instruct the charging device to heat the power battery, wherein the heating of the power battery by the charging device is based on discharging and charging the power battery, and a pulse current for heating the power battery is alternately formed during the discharging process and the charging process; The charging device comprises a bidirectional DC / DC converter, and the charging device is used to control the bidirectional DC / DC converter to form a circuit for discharging from the power battery to the charging device, and a circuit for charging from the charging device to the power battery, so as to heat the power battery during the discharging and charging processes; The first indication information includes information on the amplitude and / or frequency of the pulse current used to heat the power battery; Before sending the first indication information to the charging device, the method further includes: According to the correspondence between the preset multiple temperatures and the multiple amplitudes, determining that the maximum amplitude of the pulse current is an amplitude corresponding to the temperature of the power battery; and / or, According to the preset correspondence relationship between multiple temperatures and multiple frequencies, the frequency of the pulse current is determined to be a frequency corresponding to the temperature of the power battery.

9. The method according to claim 8, characterized in that The configuring charging parameters includes: receiving a charging voltage and a charging current sent by a BMS. Before configuring the charging parameters, the BMS obtains a temperature T of the power battery and compares the temperature T with a temperature threshold T0.

10. The method according to claim 8, characterized in that The method further comprises: When the temperature of the power battery is greater than or equal to the temperature threshold, second indication information is sent to the charging device, where the second indication information is used to instruct the charging device to stop heating the power battery.

11. The method according to any one of claims 8 to 10, characterized in that The method further comprises: Sending third indication information to the charging device, where the third indication information is used to instruct the charging device to charge the power battery, and the third indication information includes information of a charging voltage and / or a charging current.

12. The method according to claim 11, characterized in that The method further comprises: Sending fourth instruction information to the charging device, where the fourth instruction information is used to instruct the charging device to stop charging the power battery.

13. A charging device, characterized in that: include: a receiving module, configured to receive first instruction information from a control device of the power battery before the charging device charges the power battery and configures charging parameters, wherein the first instruction information is used to instruct the charging device to heat the power battery; a processing module, configured to heat the power battery according to the first indication information, wherein the heating of the power battery by the charging device is based on discharging and charging the power battery, and a pulse current for heating the power battery is alternately formed during the discharging process and the charging process; The charging device further includes a bidirectional DC / DC converter, and the processing module is specifically used for: controlling the bidirectional DC / DC converter to form a circuit for discharging from the power battery to the charging device and a circuit for charging from the charging device to the power battery, so as to heat the power battery during the discharging and charging processes; The first indication information includes information on the amplitude and / or frequency of the pulse current used to heat the power battery; Before sending the first indication information to the charging device, the processing module is further used to: According to the correspondence between the preset multiple temperatures and the multiple amplitudes, determining that the maximum amplitude of the pulse current is an amplitude corresponding to the temperature of the power battery; and / or, According to the preset correspondence relationship between multiple temperatures and multiple frequencies, the frequency of the pulse current is determined to be a frequency corresponding to the temperature of the power battery.

14. The charging device according to claim 13, characterized in that: in, The configuring charging parameters includes: receiving a charging voltage and a charging current sent by a BMS. Before configuring the charging parameters, the BMS obtains a temperature T of the power battery and compares the temperature T with a temperature threshold T0.

15. The charging device according to claim 13, characterized in that: The charging device further includes an AC / DC converter, and the AC / DC converter and the bidirectional DC / DC converter are connected between an AC power source and the power battery.

16. The charging device according to claim 14, characterized in that: The charging device also includes an energy storage battery, and the bidirectional DC / DC converter is connected between the energy storage battery and the power battery.

17. The charging device according to claim 13, characterized in that: The receiving module is further used to: receive second instruction information from the control device, where the second instruction information is used to instruct the charging device to stop heating the power battery; The processing module is further used to: stop heating the power battery according to the second indication information.

18. The charging device according to any one of claims 13 to 17, characterized in that: The receiving module is further used to: receive third instruction information from the control device, the third instruction information is used to instruct the charging device to charge the power battery, and the third instruction information includes information of charging voltage and / or charging current; The processing module is further used to charge the power battery according to the third indication information.

19. The charging device according to claim 18, characterized in that: The receiving module is further used to: receive fourth instruction information from the control device, where the fourth instruction information is used to instruct the charging device to stop charging the power battery; The processing module is further used to: stop charging the power battery according to the fourth indication information.

20. A battery management system BMS, characterized in that: include: A processing module, used for obtaining the temperature of the power battery before the charging device charges the power battery and configures charging parameters; a sending module, configured to send first instruction information to the charging device when the temperature of the power battery is lower than a temperature threshold, wherein the first instruction information is used to instruct the charging device to heat the power battery, wherein the heating of the power battery by the charging device is based on discharging and charging the power battery, and a pulse current for heating the power battery is alternately formed during the discharging process and the charging process; The charging device comprises a bidirectional DC / DC converter, and the charging device is used to control the bidirectional DC / DC converter to form a circuit for discharging from the power battery to the charging device, and a circuit for charging from the charging device to the power battery, so as to heat the power battery during the discharging and charging processes; The first indication information includes information on the amplitude and / or frequency of the pulse current used to heat the power battery; Before sending the first indication information to the charging device, the processing module is further used to: According to the correspondence between the preset multiple temperatures and the multiple amplitudes, determining that the maximum amplitude of the pulse current is an amplitude corresponding to the temperature of the power battery; and / or, According to the preset correspondence relationship between multiple temperatures and multiple frequencies, the frequency of the pulse current is determined to be a frequency corresponding to the temperature of the power battery.

21. The BMS according to claim 20, characterized in that The configuring charging parameters includes: receiving a charging voltage and a charging current sent by a BMS. Before configuring the charging parameters, the BMS obtains a temperature T of the power battery and compares the temperature T with a temperature threshold T0.

22. The BMS according to claim 20, characterized in that The sending module is also used for: When the temperature of the power battery is greater than or equal to the temperature threshold, second indication information is sent to the charging device, where the second indication information is used to instruct the charging device to stop heating the power battery.

23. The BMS according to any one of claims 20 to 22, characterized in that: The sending module is also used for: Sending third indication information to the charging device, where the third indication information is used to instruct the charging device to charge the power battery, and the third indication information includes information of a charging voltage and / or a charging current.

24. The BMS according to claim 23, characterized in that The sending module is also used for: Sending fourth instruction information to the charging device, where the fourth instruction information is used to instruct the charging device to stop charging the power battery.

25. A battery heating device, characterized in that: The invention comprises a memory and a processor, wherein the memory is used to store instructions, and the processor is used to read the instructions and execute the battery heating method according to any one of claims 1 to 12 based on the instructions.

26. A computer storage medium, characterized in that The invention comprises instructions for executing the method for heating a battery as claimed in any one of claims 1 to 12.

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