Battery management system, control method and device thereof, storage medium and program product

Abstract

The invention relates to a battery management system, a control method and device thereof, a storage medium and a program product. The control method of the battery management system comprises the steps that for each battery module in a battery device, the maximum value, the minimum value and the average value of voltage of all battery cells in the battery module are obtained, and the battery device comprises a plurality of battery modules; determining a first voltage difference according to an absolute value of a difference value between the minimum value and the average value; determining a second voltage difference according to an absolute value of a difference value between the maximum value and the average value; according to the first voltage difference and the second voltage difference, battery equalization is carried out on the battery module, and the battery equalization comprises at least one of battery active equalization and battery passive equalization. According to the invention, the active and passive hybrid equalization design of the battery can be carried out according to the maximum undervoltage difference and the maximum overvoltage difference, so that the equalization efficiency is improved, the consistency of the battery is improved, the safety of the battery is ensured, and the service life of the battery is prolonged.

Description

Technical Field

[0001] The present disclosure relates to the field of battery management, and in particular to a battery management system and a control method and device thereof, a storage medium and a program product. Background Art

[0002] With the transformation of the global energy structure and the demand for sustainable development, energy storage technology, as a key technology to balance supply and demand, improve grid stability and promote the use of renewable energy, is receiving more and more attention. BESS (Battery Energy Storage System) plays an important role in grid frequency regulation, peak-valley shaving, emergency backup and renewable energy grid connection due to its fast response, flexible configuration and simple maintenance. Summary of the invention

[0003] The inventors discovered through research that related technology battery modules are usually composed of hundreds or thousands of battery cells, which have slight differences in the manufacturing process. As the usage time increases, these differences will lead to inconsistent battery performance and affect the stability and life of the entire battery system.

[0004] In view of at least one of the above technical problems, the present disclosure provides a battery management system and a control method and device thereof, a storage medium and a program product, which adopts a battery active and passive hybrid balancing design to improve the balancing efficiency and enhance the consistency of the battery.

[0005] According to one aspect of the present disclosure, a control method for a battery management system is provided, comprising:

[0006] For each battery module in a battery device, obtaining a maximum value, a minimum value, and an average value of the voltages of all cells in the battery module, wherein the battery device includes a plurality of battery modules;

[0007] Determine a first voltage difference according to an absolute value of a difference between the minimum value and the average value;

[0008] Determining a second voltage difference according to an absolute value of a difference between the maximum value and the average value;

[0009] The battery module is subjected to battery balancing according to the first voltage difference and the second voltage difference, wherein the battery balancing includes at least one of active battery balancing and passive battery balancing.

[0010] In some embodiments of the present disclosure, performing battery balancing on the battery module according to the first voltage difference and the second voltage difference includes:

[0011] Taking the maximum value of the first voltage difference and the second voltage difference as the voltage difference of the battery module;

[0012] Determining a balancing mark of the battery module according to the magnitude of the pressure difference of the battery module;

[0013] The battery module is subjected to battery balancing according to the balancing identifier and the magnitude relationship between the first voltage difference and the second voltage difference.

[0014] In some embodiments of the present disclosure, determining the equalization flag of the battery module according to the magnitude of the pressure difference of the battery module includes:

[0015] When the voltage difference of the battery module is greater than a first voltage threshold, using a first balancing mark as a balancing mark of the battery module;

[0016] When the voltage difference of the battery module is not greater than the first voltage threshold and greater than the second voltage threshold, a second balancing mark is used as a balancing mark of the battery module, wherein the second voltage threshold is less than the first voltage threshold;

[0017] When the voltage difference of the battery module is not greater than the second voltage threshold, the third balancing mark is used as the balancing mark of the battery module.

[0018] In some embodiments of the present disclosure, performing battery balancing on the battery module according to the balancing flag and the magnitude relationship between the first voltage difference and the second voltage difference includes:

[0019] When the balancing mark of the battery module is the first balancing mark and the first voltage difference is greater than the second voltage difference, active charging balancing is performed on the battery module, and the balancing channel of the battery module is recorded as the charging channel.

[0020] In some embodiments of the present disclosure, performing battery balancing on the battery module according to the balancing flag and the magnitude relationship between the first voltage difference and the second voltage difference further includes:

[0021] When the balancing mark of the battery module is the first balancing mark and the first voltage difference is not greater than the second voltage difference, active discharge balancing and passive discharge balancing are performed on the battery module, and the balancing channel of the battery module is recorded as a discharge channel.

[0022] In some embodiments of the present disclosure, performing battery balancing on the battery module according to the balancing flag and the magnitude relationship between the first voltage difference and the second voltage difference further includes:

[0023] Count the number of discharge channels and the number of charge channels in the battery device, where one balancing channel corresponds to one battery module;

[0024] In a case where the number of the discharge channels is greater than the number of the charge channels, a first number of battery modules are converted for passive balancing, wherein the first number is a difference between the number of the discharge channels and the number of the charge channels.

[0025] In some embodiments of the present disclosure, performing battery balancing on the battery module according to the balancing flag and the magnitude relationship between the first voltage difference and the second voltage difference includes:

[0026] When the balancing mark of the battery module is the second balancing mark and the first voltage difference is greater than the second voltage difference, a charging reminder message is displayed and a balancing enable switch is turned off.

[0027] In some embodiments of the present disclosure, performing battery balancing on the battery module according to the balancing flag and the magnitude relationship between the first voltage difference and the second voltage difference includes:

[0028] When the balancing mark of the battery module is the second balancing mark and the first voltage difference is not greater than the second voltage difference, passive balancing is performed on the battery module.

[0029] In some embodiments of the present disclosure, performing battery balancing on the battery module according to the balancing flag and the magnitude relationship between the first voltage difference and the second voltage difference includes:

[0030] When the balancing mark of the battery module is the third balancing mark, the balancing enabling switch is turned off.

[0031] In some embodiments of the present disclosure, determining the equalization flag of the battery module according to the magnitude of the pressure difference of the battery module includes:

[0032] When the voltage difference of the battery module is greater than the first voltage threshold value within a first predetermined time period, using the first balancing mark as the balancing mark of the battery module;

[0033] When the voltage difference of the battery module is not greater than the first voltage threshold and greater than the second voltage threshold within a first predetermined time, a second balancing mark is used as a balancing mark of the battery module, wherein the second voltage threshold is less than the first voltage threshold;

[0034] When the voltage difference of the battery module is not greater than the second voltage threshold within a first predetermined period of time, the third balancing mark is used as the balancing mark of the battery module.

[0035] In some embodiments of the present disclosure, the control method of the battery management system further includes:

[0036] Determining whether the battery module is being charged or discharged;

[0037] When the battery module is not being charged or discharged, performing the step of performing battery balancing on the battery module according to the first voltage difference and the second voltage difference;

[0038] When the battery module is being charged and discharged, the balancing enable switch is turned off.

[0039] In some embodiments of the present disclosure, the control method of the battery management system further includes:

[0040] The state of charge SOC of the battery device is calculated.

[0041] In some embodiments of the present disclosure, calculating the state of charge (SOC) of the battery device includes:

[0042] When the battery device is charged and discharged for the first time, the open circuit SOC is calculated using the open circuit voltage;

[0043] When the difference between the open circuit SOC and the last recorded SOC is smaller than a predetermined threshold, the open circuit SOC is used as the initial SOC.

[0044] In some embodiments of the present disclosure, calculating the state of charge (SOC) of the battery device includes:

[0045] When the battery device is not charged or discharged for the first time, the current SOC is calculated using the ampere-hour integral;

[0046] When the stationary time does not exceed the second predetermined time, the current SOC is used as the initial SOC.

[0047] In some embodiments of the present disclosure, calculating the state of charge (SOC) of the battery device further includes:

[0048] When the static time exceeds a second predetermined time, calculating a calibration SOC using the open circuit voltage;

[0049] When the difference between the calibrated SOC and the current SOC is less than a predetermined threshold, taking the current SOC as an initial SOC;

[0050] When the difference between the calibrated SOC and the current SOC is not less than a predetermined threshold, the calibrated SOC is used as an initial SOC.

[0051] According to another aspect of the present disclosure, there is provided a control device, comprising:

[0052] a voltage acquisition module configured to acquire, for each battery module in a battery device, a maximum value, a minimum value and an average value of the voltages of all cells in the battery module, wherein the battery device includes a plurality of battery modules;

[0053] A voltage difference determination module, which determines a first voltage difference according to an absolute value of a difference between the minimum value and the average value; and determines a second voltage difference according to an absolute value of a difference between the maximum value and the average value;

[0054] The battery balancing module is configured to perform battery balancing on the battery module according to the first voltage difference and the second voltage difference, wherein the battery balancing includes at least one of active battery balancing and passive battery balancing.

[0055] According to another aspect of the present disclosure, there is provided a control device, comprising:

[0056] a memory configured to store instructions; and

[0057] The processor is configured to execute the instructions so that the control device implements the control method as described in any of the above embodiments.

[0058] According to another aspect of the present disclosure, a battery management system is provided, comprising the control device as described in any of the above embodiments.

[0059] In some embodiments of the present disclosure, the battery management system further includes a voltage acquisition device, an active balancing device, and a passive balancing device.

[0060] According to another aspect of the present disclosure, a computer-readable storage medium is provided, wherein the computer-readable storage medium stores computer instructions, and when the instructions are executed by a processor, the control method as described in any of the above embodiments is implemented.

[0061] According to another aspect of the present disclosure, a computer program product is provided, including a computer program, wherein when the computer program is executed by a processor, the control method as described in any of the above embodiments is implemented.

[0062] The present disclosure can perform active and passive hybrid balancing design of the battery according to the maximum undervoltage difference and the maximum overvoltage difference, thereby improving the balancing efficiency, enhancing the consistency of the battery, and further ensuring the battery safety and extending the battery life. BRIEF DESCRIPTION OF THE DRAWINGS

[0063] In order to more clearly illustrate the embodiments of the present disclosure or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present disclosure. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0064] Figure 1 Schematic diagram of some embodiments of the battery management system disclosed herein.

[0065] Figure 2 Schematic diagram of some embodiments of the control method of the battery management system disclosed in the present invention.

[0066] Figure 3 Schematic diagrams of other embodiments of the control method of the battery management system disclosed in the present invention.

[0067] Figure 4 Schematic diagram of some other embodiments of the control method of the battery management system disclosed in the present invention.

[0068] Figure 5 Schematic diagram of some other embodiments of the control method of the battery management system disclosed in the present invention.

[0069] Figure 6 Schematic diagram of some other embodiments of the control method of the battery management system disclosed in the present invention.

[0070] Figure 7 Schematic diagram of the structure of some embodiments of the control device disclosed in the present invention.

[0071] Figure 8 Schematic diagram of the structure of other embodiments of the control device disclosed in the present invention.

[0072] Fig. 9 Schematic diagrams of other embodiments of the battery management system disclosed herein. DETAILED DESCRIPTION

[0073] The technical solutions in the embodiments of the present disclosure will be clearly and completely described below in conjunction with the drawings in the embodiments of the present disclosure. Obviously, the described embodiments are only part of the embodiments of the present disclosure, rather than all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present disclosure and its application or use. Based on the embodiments in the present disclosure, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present disclosure.

[0074] Unless specifically stated otherwise, the relative arrangement of components and steps, the numerical expressions and numerical values ​​set forth in these embodiments do not limit the scope of the present disclosure.

[0075] At the same time, it should be understood that for the convenience of description, the sizes of the various parts shown in the drawings are not drawn according to the actual proportional relationship.

[0076] Technologies, methods, and equipment known to ordinary technicians in the relevant art may not be discussed in detail, but where appropriate, the technologies, methods, and equipment should be considered as part of the specification.

[0077] In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limiting. Therefore, other examples of the exemplary embodiments may have different values.

[0078] It should be noted that like reference numerals and letters refer to similar items in the following figures, and therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0079] The inventors also found through research that although the BMS system of the related art can realize basic battery monitoring and management functions, there is still room for improvement in handling complex working conditions and improving system reliability.

[0080] Figure 1 Schematic diagram of some embodiments of the battery management system disclosed in the present invention. Figure 1 As shown, the battery management system disclosed in the present invention may include an active balancing device 1 , a passive balancing device 2 , a voltage collection device 3 and a control device 4 .

[0081] In some embodiments of the present disclosure, the battery management system of the present disclosure is configured to perform battery management on a battery device.

[0082] In some embodiments of the present disclosure, the battery management system of the present disclosure may be a battery energy storage system or an energy storage BMS system.

[0083] In some embodiments of the present disclosure, the battery device includes a plurality of battery modules 5 .

[0084] In some embodiments of the present disclosure, the battery management system may include a control device 4 , a plurality of active balancing devices 1 , a plurality of passive balancing devices 2 , and a plurality of voltage acquisition devices 3 .

[0085] In some embodiments of the present disclosure, for each battery module 5 , an active balancing device 1 , a passive balancing device 2 and a voltage collection device 3 are correspondingly provided to perform battery balancing processing on the battery module 5 .

[0086] The voltage collection device 3 is configured to collect the maximum value, minimum value and average value of the voltage of all cells in each battery module 5 in the battery device; and send the maximum value, minimum value and average value of the voltage of all cells in the battery module to the control device 4.

[0087] The control device 4 is configured to receive, for each battery module in the battery device, the maximum value, minimum value and average value of the voltages of all cells in the battery module collected by the voltage collection device 3; determine a first voltage difference according to the absolute value of the difference between the minimum value and the average value; determine a second voltage difference according to the absolute value of the difference between the maximum value and the average value; and control the active balancing device 1 and the passive balancing device 2 to perform battery balancing on the battery module according to the first voltage difference and the second voltage difference, wherein the battery balancing includes at least one of active battery balancing and passive battery balancing.

[0088] The control method and device of the battery management system disclosed in the present invention are described below through specific embodiments.

[0089] Figure 2 Schematic diagram of some embodiments of the control method of the battery management system disclosed in the present invention. Figure 2 The embodiment can be executed by the battery management system of the present disclosure or the control device of the present disclosure. Figure 2 As shown, Figure 2 The method of the embodiment may include at least one of steps 100 to 400 .

[0090] Step 100: for each battery module in a battery device, obtain the maximum value, the minimum value and the average value of the voltages of all the cells in the battery module, wherein the battery device includes a plurality of battery modules.

[0091] Step 200: Determine a first voltage difference, that is, a maximum undervoltage voltage difference, according to the absolute value of the difference between the minimum value and the average value.

[0092] Step 300: Determine a second voltage difference, that is, a maximum overvoltage difference, according to the absolute value of the difference between the maximum value and the average value.

[0093] Step 400: performing battery balancing on the battery module according to the first voltage difference and the second voltage difference, wherein the battery balancing includes at least one of active battery balancing and passive battery balancing.

[0094] The above embodiments of the present disclosure can determine the maximum undervoltage differential pressure and the maximum overvoltage differential pressure according to the maximum value, minimum value and average value of the voltage of all the cells in the battery module; and perform at least one of active battery balancing and passive battery balancing on the battery module according to the maximum undervoltage differential pressure and the maximum overvoltage differential pressure. Therefore, the above embodiments of the present disclosure can perform active and passive hybrid balancing design of the battery according to the maximum undervoltage differential pressure and the maximum overvoltage differential pressure, thereby improving the balancing efficiency and the consistency of the battery, thereby ensuring the battery safety, extending the battery life and improving the system performance.

[0095] In some embodiments of the present disclosure, the control method of the battery management system may further include: determining whether the battery module is being charged or discharged; if the battery module is not being charged or discharged, executing step 400; if the battery module is being charged or discharged, turning off the balancing enable switch.

[0096] The above-mentioned embodiment of the present disclosure does not perform battery balancing during charging and discharging. If battery balancing is performed during charging and discharging, the charging and discharging effect of the battery will be affected.

[0097] In some embodiments of the present disclosure, step 400 may include at least one of steps 410 to 440 .

[0098] Step 410: taking the maximum value of the first voltage difference and the second voltage difference as the voltage difference of the battery module.

[0099] Step 420: Determine a balancing flag of the battery module according to the magnitude of the pressure difference of the battery module.

[0100] In some embodiments of the present disclosure, step 420 may include at least one of steps 421 to 423 .

[0101] Step 421 : When the voltage difference of the battery module is greater than a first voltage threshold, use a first balancing mark as a balancing mark of the battery module.

[0102] In some embodiments of the present disclosure, the first voltage threshold may be 50 mV.

[0103] In some embodiments of the present disclosure, the first equalization flag indicates that severe equalization is required.

[0104] Step 422, when the voltage difference of the battery module is not greater than the first voltage threshold and greater than the second voltage threshold, use the second balancing mark as the balancing mark of the battery module, wherein the second voltage threshold is less than the first voltage threshold.

[0105] In some embodiments of the present disclosure, the second voltage threshold may be 20 mV.

[0106] In some embodiments of the present disclosure, the second equalization flag indicates that slight equalization is required.

[0107] In some embodiments of the present disclosure, severe equalization and slight equalization affect the current magnitude during charging and discharging.

[0108] Step 423: When the voltage difference of the battery module is not greater than the second voltage threshold, use the third balancing mark as the balancing mark of the battery module.

[0109] The above embodiments of the present disclosure can determine different equalization marks according to different value ranges of the pressure difference. Therefore, the above embodiments of the present disclosure can determine different equalization forms according to different value ranges of the pressure difference to adapt to different working conditions and battery states, and achieve more accurate battery management, thereby further improving the equalization efficiency and improving the consistency of the battery. For example: when the difference between the average voltage and the maximum voltage is too large, passive equalization is turned on for mild equalization, and active equalization and passive equalization are turned on together for severe cases.

[0110] The severe balance and slight balance marks in the above embodiment of the present disclosure can also determine the current size during charging and discharging.

[0111] In some other embodiments of the present disclosure, step 420 may include at least one of steps 42a to 42b.

[0112] Step 42a: When the voltage difference of the battery module is greater than the first voltage threshold for a first predetermined time period, use the first balancing mark as the balancing mark of the battery module.

[0113] In some embodiments of the present disclosure, the first predetermined time may be 100 ms.

[0114] Step 42b, when the voltage difference of the battery module is not greater than the first voltage threshold and greater than the second voltage threshold for a first predetermined period of time, a second balancing mark is used as a balancing mark of the battery module, wherein the second voltage threshold is less than the first voltage threshold.

[0115] Step 42c: when the voltage difference of the battery module is not greater than the second voltage threshold within a first predetermined time period, use the third balancing mark as the balancing mark of the battery module.

[0116] The above embodiments of the present disclosure can determine different equalization forms according to different value ranges of the pressure difference within the continuous predetermined time to adapt to different working conditions and battery states, and achieve more accurate battery management, thereby further improving the equalization efficiency and improving the consistency of the battery. The above embodiments of the present disclosure can avoid errors and more accurately determine the pressure difference between the battery cells through the pressure difference situation for the first continuous predetermined time, thereby achieving more accurate battery equalization management.

[0117] Step 430: Perform battery balancing on the battery module according to the balancing flag and the magnitude relationship between the first voltage difference and the second voltage difference.

[0118] The above-mentioned embodiments of the present disclosure can perform at least one of active battery balancing and passive battery balancing on the battery module according to the balancing mark and the magnitude relationship between the first voltage difference and the second voltage difference, thereby different forms of active and passive hybrid balancing designs can be performed for different situations to adapt to different working conditions and battery states, and achieve more accurate battery management, thereby further improving the balancing efficiency and enhancing the consistency of the battery, thereby better ensuring battery safety, extending battery life, and improving system performance.

[0119] In some embodiments of the present disclosure, step 430 may include at least one of steps 431 to 434 .

[0120] Step 431 , when the balancing mark of the battery module is the first balancing mark and the first voltage difference is greater than the second voltage difference, active charging balancing is performed on the battery module, and the balancing channel of the battery module is recorded as the charging channel.

[0121] In the above embodiment of the present disclosure, when the difference between the average voltage and the minimum voltage is too large, active charging equalization can be performed to equalize the channels that need equalization.

[0122] The active balancing of the above-mentioned embodiments of the present disclosure can transfer energy from high-voltage cells to low-voltage cells through a bidirectional DC-DC converter to achieve energy reuse. In the active balancing of the above-mentioned embodiments of the present disclosure, energy can flow bidirectionally between battery cells, not only from high-voltage cells to low-voltage cells, but also from low-voltage cells to high-voltage cells. In the active balancing of the above-mentioned embodiments of the present disclosure, the released energy is absorbed by other battery cells, thereby improving energy utilization.

[0123] Active balancing in the above embodiment of the present disclosure: Since energy can flow bidirectionally between battery cells, energy reuse is achieved, so it is called active balancing. The main feature of active balancing in the above embodiment of the present disclosure is the bidirectional transfer of energy, which is carried out actively.

[0124] Step 432, when the balancing mark of the battery module is the first balancing mark and the first voltage difference is not greater than the second voltage difference, discharge active balancing and passive balancing are performed on the battery module, and the balancing channel of the battery module is recorded as a discharge channel.

[0125] In the above embodiment of the present disclosure, when the difference between the average voltage and the highest voltage is too large, passive balancing is turned on for minor balancing, and active balancing and passive balancing are turned on at the same time when serious balancing is required. Therefore, the above embodiment of the present disclosure can achieve battery balancing faster and achieve battery consistency faster.

[0126] Step 433, counting the number of discharge channels and the number of charge channels in the battery device, wherein one balancing channel corresponds to one battery module.

[0127] Step 434, when the number of the discharge channels is greater than the number of the charge channels, convert a first number of battery modules for passive balancing, wherein the first number is the difference between the number of the discharge channels and the number of the charge channels.

[0128] The above embodiment of the present disclosure determines the number of charging channels and discharging channels in active balancing, and when the number of discharging channels is greater than the number of charging channels, the difference between the discharging channels and the charging channels can be converted into passive balancing.

[0129] In the above embodiment of the present disclosure, when the number of discharge channels is greater than the number of charging channels, the first number of battery modules can be converted for passive balancing. It can be seen that the number of discharge channels and the number of charging channels for active balancing are equal. Therefore, the active balancing of the above embodiment of the present disclosure transfers energy from high-voltage cells to low-voltage cells through a bidirectional DC-DC converter to achieve energy reuse. In the active balancing of the above embodiment of the present disclosure, energy can flow bidirectionally between battery cells, not only from high-voltage cells to low-voltage cells, but also from low-voltage cells to high-voltage cells.

[0130] Therefore, the above embodiment of the present disclosure can also maintain the balance of charging and discharging without raising the voltage of the bus bar.

[0131] In some embodiments of the present disclosure, step 430 may include at least one step from step 435 to step 437 in addition to at least one step from step 431 to step 434 .

[0132] Step 435 , when the equalization mark of the battery module is the second equalization mark and the first voltage difference is greater than the second voltage difference, a charging reminder message is displayed and a equalization enable switch is turned off.

[0133] The above-mentioned embodiments of the present disclosure can send a charging reminder to the user when the difference between the average voltage and the lowest voltage is not too large and there is a slight balancing mark; the above-mentioned embodiments of the present disclosure can also determine whether to perform active charging balancing based on user instructions.

[0134] In the above embodiment of the present disclosure, when the difference between the average voltage and the highest voltage is greater than the second voltage threshold, a charging reminder is issued to remind the user that there is a slight undervoltage problem and to remind the user to pay attention to whether the voltage difference continues to expand. Therefore, the above embodiment of the present disclosure can avoid frequent active charging balance, achieve more reasonable battery balance control, and further achieve energy saving.

[0135] Step 436: When the balancing mark of the battery module is the second balancing mark and the first voltage difference is not greater than the second voltage difference, passive balancing is performed on the battery module.

[0136] The above embodiment of the present disclosure performs passive balancing when the difference between the average voltage and the highest voltage is not too large and there is a slight balancing mark. The main feature of passive balancing in the above embodiment of the present disclosure is the unidirectional dissipation of energy without active energy redistribution.

[0137] The main function of the passive equalization resistor in the above embodiment of the present disclosure is to convert the excess energy of the overcharged battery cells into heat energy and release it. The passive equalization in the above embodiment of the present disclosure helps to reduce the voltage of these battery cells to keep them consistent with other battery cells. By converting the excess energy into heat energy, the battery cells can be prevented from being overcharged, thereby reducing the risk of battery damage.

[0138] Step 437 , when the balancing mark of the battery module is the third balancing mark, turn off the balancing enable switch.

[0139] The above embodiments of the present disclosure can avoid frequent active or passive balancing of the battery when the pressure difference is not large, thereby achieving more reasonable battery balancing control and further realizing energy saving. Therefore, the above embodiments of the present disclosure can adapt to different working conditions and battery states and achieve more accurate battery management.

[0140] Figure 3 Schematic diagrams of other embodiments of the control method of the battery management system disclosed in the present invention. Figure 3 The embodiments may be executed by the battery management system of the present disclosure or the control device of the present disclosure. Figure 3 The method of the embodiment may include at least one of steps 301 to 315 .

[0141] Step 301, obtaining cell information, and then executing steps 302 and 306.

[0142] In some embodiments of the present disclosure, step 301 may include: for each battery module in the battery device, obtaining the maximum, minimum and average values ​​of the voltages of all the cells in the battery module; determining a first voltage difference based on the absolute value of the difference between the minimum value and the average value; determining a second voltage difference based on the absolute value of the difference between the maximum value and the average value; and taking the maximum value of the first voltage difference and the second voltage difference as the voltage difference of the battery module.

[0143] Step 302, determining whether the voltage difference of the battery module is not greater than a first voltage threshold and greater than a second voltage threshold, wherein the second voltage threshold is less than the first voltage threshold.

[0144] In some embodiments of the present disclosure, the first voltage threshold may be 50 mV, and the second voltage threshold may be 20 mV.

[0145] Step 303 , when the voltage difference of the battery module is not greater than the first voltage threshold and greater than the second voltage threshold, counting the time during which the voltage difference of the battery module is not greater than the first voltage threshold and greater than the second voltage threshold.

[0146] Step 304 , determining whether the voltage difference of the battery module is not greater than the first voltage threshold and is greater than the second voltage threshold for a period greater than a first predetermined time.

[0147] In some embodiments of the present disclosure, the first predetermined time may be 100 ms.

[0148] Step 305 , when the voltage difference of the battery module is not greater than the first voltage threshold and the time when it is greater than the second voltage threshold is greater than the first predetermined time, the second balancing mark is used as the balancing mark of the battery module. Then, step 310 is executed.

[0149] In some embodiments of the present disclosure, the second equalization flag indicates that slight equalization is required.

[0150] Step 306, determining whether the voltage difference of the battery module is greater than a first voltage threshold.

[0151] Step 307 , when the voltage difference of the battery module is greater than the first voltage threshold, counting the time during which the voltage difference of the battery module is greater than the first voltage threshold.

[0152] Step 308 , determining whether the time during which the voltage difference of the battery module is greater than the first voltage threshold is greater than a first predetermined time.

[0153] Step 309 : When the voltage difference of the battery module is greater than the first voltage threshold for a period greater than a first predetermined period, the first balancing mark is used as the balancing mark of the battery module. Then, step 310 is executed.

[0154] In some embodiments of the present disclosure, the first equalization flag indicates that severe equalization is required.

[0155] In the above-mentioned embodiment of the present disclosure, steps 301 to 309 compare the difference between the maximum and minimum values ​​of the cell voltage in the module and the average value. After the difference is met for 100 ms, it is determined whether to perform slight equalization or severe equalization according to the size of the voltage difference.

[0156] Step 310, determining whether the battery module is being charged or discharged. If the battery module is being charged or discharged, execute step 316; otherwise, if the battery module is not being charged or discharged, execute step 311.

[0157] Step 311, when the equalization mark of the battery module is the second equalization mark (for example, the voltage difference is greater than 20mV and less than 50mV), and the first voltage difference is greater than the second voltage difference, display a charging reminder message and turn off the equalization enable switch; when the equalization mark of the battery module is the first equalization mark (for example, the voltage difference is greater than 50mV), and the first voltage difference is greater than the second voltage difference, execute step 312; otherwise, in other cases, execute step 313.

[0158] Step 312, actively charge and balance the battery module, and record the balancing channel of the battery module as the charging channel. Then, step 315 is executed.

[0159] In the above embodiment of the present disclosure, when there is no charging or discharging, active charging balancing is performed when the difference between the average voltage and the minimum voltage is too large, and the channels that need balancing are balanced.

[0160] Step 313, when the balancing mark of the battery module is the second balancing mark and the first voltage difference is not greater than the second voltage difference, perform passive balancing on the battery module; when the balancing mark of the battery module is the first balancing mark and the first voltage difference is not greater than the second voltage difference, execute step 314.

[0161] Step 314 , performing active discharge balancing and passive discharge balancing on the battery module, and recording the balancing channel of the battery module as a discharge channel.

[0162] In the above embodiments of the present disclosure, when the difference between the average voltage and the highest voltage is too large, passive balancing is enabled for minor balancing, and active balancing and passive balancing are enabled together for serious balancing.

[0163] In some embodiments of the present disclosure, the control method may further include: by judging the number of charging channels and discharging channels in active balancing, when the number of discharging channels is greater than the number of charging channels, converting the difference between the discharging channels and the charging channels into passive balancing.

[0164] Step 315, balancing is completed.

[0165] Step 316, balance off. That is, turn off the balance enable switch

[0166] The above-mentioned embodiment of the present disclosure first determines the charging balance and then determines the discharging balance. Charging can only be performed by active balancing, and discharging should select active balancing or passive balancing for the battery according to the situation. Passive balancing is performed when the charging channel is not equal to the discharging channel, and active balancing is performed when the charging channel is equal to the discharging channel. This is done to maintain the balance of charging and discharging and not to raise the voltage of the bus.

[0167] The above-mentioned embodiments of the present disclosure adopt a battery active and passive hybrid balancing design, which can improve the balancing efficiency and optimize the balancing control strategy using intelligent algorithms such as artificial intelligence and machine learning to adapt to different working conditions and battery states, thereby achieving more accurate battery management.

[0168] In some embodiments of the present disclosure, the control method of the battery management system may further include: calculating the SOC (state of charge) of the battery device. The following describes the SOC calculation method of the battery device through specific embodiments.

[0169] The above embodiments of the present disclosure can combine multiple methods to improve the accuracy and stability of SOC estimation, which plays a key role in the stable operation of the entire system.

[0170] Figure 4 Schematic diagram of some other embodiments of the control method of the battery management system disclosed in the present invention. Figure 4 The embodiments may be executed by the battery management system of the present disclosure or the control device of the present disclosure. Figure 4 Specifically, it is a schematic diagram of a method for calculating the SOC of a battery device in some embodiments of the present disclosure. Figure 4 The control method of the battery management system of the embodiment may include: Figure 2 or Figure 3 In addition to at least one step in the embodiment, at least one step from step 41 to step 45 may also be included.

[0171] In step 41, when the battery device is charged or discharged for the first time, the open circuit SOC is calculated using the open circuit voltage (OCV).

[0172] In some embodiments of the present disclosure, the first charge and discharge (first power-on) refers to the first charge and discharge (first power-on) after power failure.

[0173] Step 42: When the difference between the open circuit SOC and the last recorded SOC is less than a predetermined threshold, the open circuit SOC is used as the initial SOC.

[0174] In some embodiments of the present disclosure, the last recorded SOC is the SOC recorded before the device was powered off.

[0175] The above-mentioned embodiments of the present disclosure can realize real-time correction of SOC. In the case of the first charge and discharge after power failure, the accumulated error of the ampere-hour integration method can be recalibrated through the open circuit voltage (OCV), and the adaptive parameters can be used to dynamically adjust the integral coefficient of the ampere-hour integration method according to the charge and discharge characteristics of the battery to improve the estimation accuracy.

[0176] Step 43: when the difference between the open circuit SOC and the last recorded SOC is not less than a predetermined threshold, the current SOC value is estimated according to the power-off time.

[0177] Step 44 : When the difference between the estimated SOC and the open-circuit SOC is less than a predetermined threshold, the estimated SOC is used as the initial SOC.

[0178] Step 45 : When the difference between the estimated SOC and the open circuit SOC is not less than a predetermined threshold, prompt the user.

[0179] Figure 5 Schematic diagram of some other embodiments of the control method of the battery management system disclosed in the present invention. Figure 5 The embodiments may be executed by the battery management system of the present disclosure or the control device of the present disclosure. Figure 5 Specifically, it is a schematic diagram of a method for calculating the SOC of a battery device in some embodiments of the present disclosure. Figure 5 The control method of the battery management system of the embodiment may include: Figures 2 to 4 In addition to at least one step in the embodiment, at least one step from step 51 to step 55 may also be included.

[0180] Step 51 : when the battery device is not charged or discharged for the first time, the current SOC is calculated using the ampere-hour integral.

[0181] Step 52: When the rest time does not exceed the second predetermined time, the current SOC is used as the initial SOC.

[0182] In some embodiments of the present disclosure, the quiescent state refers to quiescent state or standby state without power failure.

[0183] In some embodiments of the present disclosure, the second predetermined time may be 5 minutes.

[0184] In the above embodiments of the present disclosure, after the battery is charged and discharged, the battery voltage is unstable and may drop or rise. The battery voltage needs to be left standing until the voltage stabilizes before it can be used for judgment.

[0185] In some embodiments of the present disclosure, the second predetermined time is also not fixed and can be changed according to different battery charge and discharge test data.

[0186] Step 53: When the rest time exceeds the second predetermined time, the open circuit voltage is used to calculate a calibration SOC.

[0187] Step 54 : When the difference between the calibrated SOC and the current SOC is less than a predetermined threshold, the current SOC is used as the initial SOC.

[0188] Step 55 , when the difference between the calibration SOC and the current SOC is not less than a predetermined threshold, the calibration SOC is used as the initial SOC to perform fuzzy Kalman filtering processing.

[0189] The above-mentioned embodiments of the present disclosure can realize real-time correction of SOC. At the end of each charging or discharging cycle, the accumulated error of the ampere-hour integration method is recalibrated through the open circuit voltage (OCV), and the adaptive parameters are used to dynamically adjust the integral coefficient of the ampere-hour integration method according to the charging and discharging characteristics of the battery to improve the estimation accuracy.

[0190] Figure 6 Schematic diagram of some other embodiments of the control method of the battery management system disclosed in the present invention. Figure 6 The embodiments may be executed by the battery management system of the present disclosure or the control device of the present disclosure. Figure 6 Specifically, it is a schematic diagram of a method for calculating the SOC of a battery device in some embodiments of the present disclosure. Figure 6 The control method of the battery management system of the embodiment may include: Figures 2 to 5 In addition to at least one step in the embodiment, at least one step from step 61 to step 68 may also be included.

[0191] Figure 6 The embodiment discloses a method for calculating the SOC of a BMS. The operation logic mainly issues charge and discharge requests based on the current operating status of the battery cell and the user's predetermined operation instructions, and adjusts the charge and discharge currents set under different set conditions. The first-level warning of undervoltage of a single battery cell will enable charging, and the charging current will be set according to different conditions. The system charging process contains temperature difference current limiting logic, temperature current limiting logic, and single voltage current limiting logic. After the three current limiting logics, the minimum current limiting value is taken as the final current limiting value.

[0192] Step 61, the system is powered on and enters standby mode.

[0193] Step 62, the open circuit SOC is calculated using the open circuit voltage.

[0194] Step 63, determining whether the battery device is currently in a charging or discharging stage.

[0195] Step 64, when the battery device is in the charging or discharging stage, determine whether it is the first charging or discharging. If it is the first charging or discharging, execute step 65; if it is not the first charging or discharging, execute step 66.

[0196] In some embodiments of the present disclosure, the first charge and discharge refers to the first charge and discharge after power failure.

[0197] In step 65, the open circuit SOC is used as the initial SOC of the ampere-hour integration method. Then, step 68 is executed.

[0198] In some embodiments of the present disclosure, step 65 may include: in the case of the first charge and discharge, using the open circuit voltage as the starting value, if the difference with the last ending SOC is too large, checking the system power-off time, and reducing the SOC value this time according to the power-off time.

[0199] In some embodiments of the present disclosure, in the case of the first charge and discharge, step 65 may include: Figure 4 At least one of steps 41 to 45 of the embodiment.

[0200] Step 66, determining whether the resting time exceeds the second predetermined time. If the resting time does not exceed the second predetermined time, executing step 67; otherwise, if the resting time exceeds the second predetermined time, executing step 65, that is, executing the step of obtaining the SOC by integrating the ampere-hour and selecting the SOC of the open circuit voltage method as the initial SOC value.

[0201] In the above embodiments of the present disclosure, when the system is static and stable, the voltage of a single chip will have different characteristics during charging and discharging and during static state, and the open circuit voltage calculated during static state will be more accurate.

[0202] In some embodiments of the present disclosure, in the case of non-first charge and discharge, step 65 may include: Figure 5 At least one of steps 53 to 55 of the embodiment.

[0203] Step 67, using the SOC obtained by the most recent ampere-hour integration method as the initial SOC. Then, step 68 is executed.

[0204] Step 68, using fuzzy Kalman filtering to process the current SOC.

[0205] In some embodiments of the present disclosure, the present disclosure Figures 4 to 6The SOC calculation method of the embodiment may include: if it is not the first time to power on, the SOC uses the value of the first power-on to perform ampere-hour integration calculation. After the system stops charging and discharging, the standby time exceeds five minutes. If it exceeds five minutes, the SOC is recalculated using the open circuit voltage to make an SOC correction judgment; if it does not exceed, the SOC is calculated using the ampere-hour integration.

[0206] In some specific embodiments of the present disclosure, Figures 4 to 6 The SOC calculation method of the embodiment may include: when the system is powered on for the first time, the SOC is calculated using the open circuit voltage to be 80%. At this time, the SOC is not much different from the SOC recorded when the power was turned off last time, and 80% is used as the initial SOC for this time. After the system is discharged for a period of time, the discharge is stopped and the SOC is processed using the ampere-hour integral calculation, and the SOC drops to 60%. If it is left at rest for more than five minutes, the SOC is calculated once using the open circuit voltage method and the SOC is brought into the process to obtain a SOC of 58%, and the SOC is 58% at this time; if it is not left at rest for more than five minutes, 60% will be used as the ampere-hour integral calculation for the next charge and discharge.

[0207] The above-mentioned embodiments of the present disclosure can realize real-time correction of SOC. At the end of each charging or discharging cycle, the accumulated error of the ampere-hour integration method is recalibrated through the open circuit voltage (OCV), and the adaptive parameters are used to dynamically adjust the integral coefficient of the ampere-hour integration method according to the charging and discharging characteristics of the battery to improve the estimation accuracy.

[0208] In some embodiments of the present disclosure, the control method of the battery management system may further include: correcting the SOC of the battery device.

[0209] In some embodiments of the present disclosure, the SOC correction method may include: when the highest cell voltage reaches the full charge value and the SOC does not reach 100%, the SOC is forcibly corrected to 100%; when the lowest cell voltage reaches the severe undervoltage threshold, the SOC is forcibly corrected to 0%.

[0210] In some embodiments of the present disclosure, the SOC correction method may include: when the highest single cell voltage is less than a severe overvoltage threshold and is in a charging state, the highest SOC value is 99.99% and must not reach 100%.

[0211] In some embodiments of the present disclosure, when the battery is severely under-voltage, it will affect the battery performance. In order to protect the battery, the maximum SOC value is limited to 99.99%. The SOC can only be forced to 100% after the battery performance is restored and fully charged next time.

[0212] Figure 7 Schematic diagram of the structure of some embodiments of the control device disclosed in the present invention. Figure 7 As shown, the control device disclosed herein may include a voltage acquisition module 71 , a voltage difference determination module 72 and a battery balancing module 73 .

[0213] The voltage acquisition module 71 is configured to acquire, for each battery module in the battery device, a maximum value, a minimum value and an average value of the voltages of all the cells in the battery module, wherein the battery device includes a plurality of battery modules.

[0214] The voltage difference determination module 72 determines the first voltage difference according to the absolute value of the difference between the minimum value and the average value; and determines the second voltage difference according to the absolute value of the difference between the maximum value and the average value.

[0215] The battery balancing module 73 is configured to perform battery balancing on the battery module according to the first voltage difference and the second voltage difference, wherein the battery balancing includes at least one of active battery balancing and passive battery balancing.

[0216] In some embodiments of the present disclosure, the battery balancing module 73 may be configured to use the maximum value of the first voltage difference and the second voltage difference as the voltage difference of the battery module; determine the balancing flag of the battery module according to the magnitude of the voltage difference of the battery module; and perform battery balancing on the battery module according to the balancing flag and the magnitude relationship between the first voltage difference and the second voltage difference.

[0217] In some embodiments of the present disclosure, the battery balancing module 73, when determining the balancing mark of the battery module according to the size of the pressure difference of the battery module, can be configured to use the first balancing mark as the balancing mark of the battery module when the pressure difference of the battery module is greater than the first voltage threshold; use the second balancing mark as the balancing mark of the battery module when the pressure difference of the battery module is not greater than the first voltage threshold and greater than the second voltage threshold, wherein the second voltage threshold is less than the first voltage threshold; and use the third balancing mark as the balancing mark of the battery module when the pressure difference of the battery module is not greater than the second voltage threshold.

[0218] In some embodiments of the present disclosure, the battery balancing module 73, when performing battery balancing on the battery module according to the balancing identifier and the magnitude relationship between the first voltage difference and the second voltage difference, can be configured to, when the balancing identifier of the battery module is the first balancing identifier and the first voltage difference is greater than the second voltage difference, perform active charging balancing on the battery module and record the balancing channel of the battery module as the charging channel.

[0219] In some embodiments of the present disclosure, the battery balancing module 73, when performing battery balancing on the battery module according to the balancing identifier and the magnitude relationship between the first voltage difference and the second voltage difference, can also be configured to, when the balancing identifier of the battery module is the first balancing mark and the first voltage difference is not greater than the second voltage difference, perform discharge active balancing and passive balancing on the battery module, and record the balancing channel of the battery module as a discharge channel.

[0220] In some embodiments of the present disclosure, the battery balancing module 73, when performing battery balancing on the battery module according to the balancing identifier and the magnitude relationship between the first voltage difference and the second voltage difference, can also be configured to count the number of discharge channels and the number of charging channels in the battery device, wherein one balancing channel corresponds to one battery module; when the number of discharge channels is greater than the number of charging channels, a first number of battery modules are converted for passive balancing, wherein the first number is the difference between the number of discharge channels and the number of charging channels.

[0221] The battery balancing module 73, when performing battery balancing on the battery module according to the balancing mark and the magnitude relationship between the first voltage difference and the second voltage difference, can be configured to display a charging reminder message and turn off the balancing enable switch when the balancing mark of the battery module is the second balancing mark and the first voltage difference is greater than the second voltage difference.

[0222] The battery balancing module 73, when performing battery balancing on the battery module according to the balancing mark and the magnitude relationship between the first voltage difference and the second voltage difference, can be configured to perform passive balancing on the battery module when the balancing mark of the battery module is the second balancing mark and the first voltage difference is not greater than the second voltage difference.

[0223] The battery balancing module 73, when performing battery balancing on the battery module according to the balancing identifier and the magnitude relationship between the first voltage difference and the second voltage difference, may also be configured to turn off a balancing enable switch when the balancing identifier of the battery module is a third balancing mark.

[0224] In some embodiments of the present disclosure, the battery balancing module 73, when determining the balancing mark of the battery module according to the size of the pressure difference of the battery module, can be configured to use the first balancing mark as the balancing mark of the battery module when the pressure difference of the battery module is greater than the first voltage threshold for a first consecutive predetermined time; use the second balancing mark as the balancing mark of the battery module when the pressure difference of the battery module is not greater than the first voltage threshold and greater than the second voltage threshold for a first consecutive predetermined time, wherein the second voltage threshold is less than the first voltage threshold; and use the third balancing mark as the balancing mark of the battery module when the pressure difference of the battery module is not greater than the second voltage threshold for a first consecutive predetermined time.

[0225] In some embodiments of the present disclosure, the control device can also be configured to determine whether the battery module is being charged or discharged; if the battery module is not being charged or discharged, perform the operation of battery balancing on the battery module based on the first voltage difference and the second voltage difference; if the battery module is being charged or discharged, turn off the balancing enable switch.

[0226] In some embodiments of the present disclosure, the control device may also be configured to calculate a state of charge SOC of the battery device.

[0227] In some embodiments of the present disclosure, when calculating the state of charge SOC of the battery device, the control device can be configured to use the open circuit SOC calculated by the open circuit voltage when the battery device is charged and discharged for the first time; when the difference between the open circuit SOC and the last recorded SOC is less than a predetermined threshold, use the open circuit SOC as the initial SOC.

[0228] In some embodiments of the present disclosure, when calculating the state of charge SOC of the battery device, the control device can be configured to use ampere-hour integration to calculate the current SOC when the battery device is not charged or discharged for the first time; and use the current SOC as the initial SOC when the standing time does not exceed a second predetermined time.

[0229] In some embodiments of the present disclosure, when calculating the state of charge SOC of the battery device, the control device can be configured to use the open circuit voltage to calculate a calibration SOC when the standing time exceeds a second predetermined time; when the difference between the calibration SOC and the current SOC is less than a predetermined threshold, use the current SOC as the initial SOC; when the difference between the calibration SOC and the current SOC is not less than a predetermined threshold, use the calibration SOC as the initial SOC.

[0230] Figure 8Schematic diagram of the structure of some other embodiments of the control device disclosed in the present invention. Figure 8 As shown, the control device of the present disclosure may include a memory 61 and a processor 82 .

[0231] The memory 81 is used to store instructions. The processor 82 is coupled to the memory 81 . The processor 82 is configured to execute the control method of the battery management system involved in the above embodiment based on the instructions stored in the memory.

[0232] like Figure 8 As shown, the control device further includes a communication interface 83 for information exchange with other devices. At the same time, the control device further includes a bus 84, through which the processor 82, the communication interface 83, and the memory 81 communicate with each other.

[0233] The memory 81 may include a high-speed RAM memory, and may also include a non-volatile memory, such as at least one disk memory. The memory 81 may also be a memory array. The memory 81 may also be divided into blocks, and the blocks may be combined into virtual volumes according to certain rules.

[0234] In addition, the processor 82 may be a central processing unit (CPU), or may be an application specific integrated circuit (ASIC), or may be configured to implement one or more integrated circuits of the embodiments of the present disclosure.

[0235] Fig. 9 Schematic diagrams of other embodiments of the battery management system disclosed in the present invention. Fig. 9 As shown, the battery management system disclosed in the present invention may include an active balancing device, a passive balancing device 2 , a voltage collection device 3 and a control device 4 .

[0236] Fig. 9 The active balancing device of the embodiment may include a bidirectional DC / DC (direct current / direct current conversion module) 11 , an active balancing control switch 12 and a shunt 13 .

[0237] The control device 4 can be implemented as any of the above embodiments (for example Figure 7 or Figure 8 Embodiment) described in the control device.

[0238] The voltage acquisition device 3 is configured to acquire the voltage of each cell in the battery module 5 and transmit it to the control device 4 via the SPI bus.

[0239] In some embodiments of the present disclosure, inside the battery system, the battery transmits data via the SPI bus, and outside the system, the battery information is transmitted via the CAN bus. The isolated bus design can avoid data conflicts and ensure the stability of data transmission.

[0240] In some embodiments of the present disclosure, the voltage collection device 3 may be implemented as a voltage collection chip.

[0241] In some embodiments of the present disclosure, the control device 4 may be implemented as a main control MCU.

[0242] In some embodiments of the present disclosure, the system collects the total current and the balanced circuit current through the shunt 13, as well as the system total voltage and the balanced circuit voltage.

[0243] In some embodiments of the present disclosure, the total system voltage may be the total voltage of the battery module.

[0244] In some embodiments of the present disclosure, the balancing circuit refers to a whole circuit including a bidirectional DCDC 11, a voltage acquisition device, an active balancing control switch 12, a passive balancing device 2, a voltage and current acquisition circuit, and the like.

[0245] In some embodiments of the present disclosure, current flowing through a shunt will generate a voltage at the shunt. The current value is calculated by collecting the voltage on the shunt to fit the current relationship. The voltage collection chip can collect the battery voltage of each piece to use as a balancing voltage, and the voltage of each piece is accumulated to obtain the total system voltage.

[0246] In some embodiments of the present disclosure, the resistance value of the resistor of the shunt 13 is 0.001-0.009 ohm.

[0247] In some embodiments of the present disclosure, the resistance value of the resistor on the right side of the bidirectional DCDC11 is 1-10 ohms, and the current is relatively small.

[0248] The above-mentioned embodiments of the present disclosure use a bidirectional DCDC converter, which can evenly transfer energy back to the battery cell and reduce energy loss.

[0249] In some embodiments of the present disclosure, the passive balancing resistor in the passive balancing device 2 is used to consume battery energy.

[0250] In some embodiments of the present disclosure, Fig. 9 As shown, a passive balancing resistor is connected in parallel to the single-chip battery in the passive balancing device 2, and a switch is used to control the conduction. When passive balancing is required, the switch is turned on, and current flows through the resistor, consuming the energy on the single battery to achieve passive balancing. The voltage collection device 3 controls the on and off of the switch. When passive balancing is required, the control device 4 sends an instruction to the voltage collection device 3.

[0251] In some embodiments of the present disclosure, in passive balancing, a switch on the passive balancing device 2 on the corresponding channel is selected, and the control device 4 sends a control instruction to the voltage acquisition device 3, and the voltage acquisition device 3 controls the corresponding switch to be turned on and off.

[0252] In the above embodiments of the present disclosure, the energy of the overcharged battery cells is released by using resistors to convert the excess electrical energy into heat energy. In the balanced state, the energy can only flow from the high voltage cells to the resistors and eventually dissipate in the form of heat energy. The released energy cannot be reused, resulting in energy waste.

[0253] Passive balancing in the above embodiments of the present disclosure: Since energy can only be released through resistance and cannot be reused, it is called "passive" balancing. The main feature of passive balancing in the above embodiments of the present disclosure is the one-way dissipation of energy without active energy redistribution.

[0254] The main function of the passive equalization resistor in the above embodiment of the present disclosure is to convert the excess energy of the overcharged battery cells into heat energy and release it. The passive equalization in the above embodiment of the present disclosure helps to reduce the voltage of these battery cells to keep them consistent with other battery cells. By converting the excess energy into heat energy, the battery cells can be prevented from being overcharged, thereby reducing the risk of battery damage.

[0255] In some embodiments of the present disclosure, when the system has a single-chip battery voltage difference that is too large, the system performs active balancing through bidirectional DCDC, controlling the PWM output by the MCU to control the direction and current of the bidirectional DCDC, or performs passive balancing through passive balancing resistors.

[0256] In some embodiments of the present disclosure, the control device 4 can be configured to perform PI control by using the average voltage of a single battery as a set value and subtracting it from the lowest single-chip voltage to be balanced during active balancing. The control amount is used as the control amount of the PWM duty cycle to adjust the voltage of the bidirectional DCDC. The MCU controls the direction of the bidirectional DCDC through an IO port to charge and discharge the battery.

[0257] In some embodiments of the present disclosure, Fig. 9 As shown, the battery device includes multiple battery modules 5. For each battery module 5, a corresponding balancing circuit is set respectively. One balancing circuit includes a passive balancing device 2, a voltage acquisition device 3, a bidirectional DC / DC 11, an active balancing control switch 12 and a shunt 13.

[0258] In some embodiments of the present disclosure, in the active balancing of the battery module 5, each time the active balancing is performed, the active balancing control switch 12 may select a single cell for active charging balancing and active discharging balancing.

[0259] In some embodiments of the present disclosure, active balancing refers to the control device 4 selecting Fig. 9 The switch in the active balancing control switch 12 opens the corresponding channel switch that needs to be balanced, and uses bidirectional DCDC to exchange energy between the single battery and the bus.

[0260] In some embodiments of the present disclosure, the balancing channel may refer to a battery channel whose single-chip lowest voltage is lower than the single-chip average voltage by a first voltage threshold (eg, 50 mv). In this case, the balancing channel is a charging balancing channel.

[0261] In some embodiments of the present disclosure, the balancing channel may also refer to a battery channel whose single-chip maximum voltage is higher than the single-chip average voltage by a first voltage threshold (eg, 50 mv). In this case, the balancing channel is a discharge balancing channel.

[0262] In some embodiments of the present disclosure, in a battery device, the number of charging balancing channels is equal to the number of discharging balancing channels.

[0263] The active balancing of the above embodiment of the present disclosure transfers energy from high-voltage cells to low-voltage cells through a bidirectional DC-DC converter, thereby realizing energy reuse. In the active balancing of the above embodiment of the present disclosure, energy can flow bidirectionally between battery cells, not only from high-voltage cells to low-voltage cells, but also from low-voltage cells to high-voltage cells. In the active balancing of the above embodiment of the present disclosure, the released energy is absorbed by other battery cells, thereby improving energy utilization.

[0264] Active balancing in the above embodiments of the present disclosure is called active balancing because energy can flow bidirectionally between battery cells, thus achieving energy reuse. The main feature of active balancing is the bidirectional transfer of energy, which is carried out actively.

[0265] In some embodiments of the present disclosure, the battery management system also includes an NTC thermistor, wherein the system places the NTC thermistor on each battery to collect temperature information of the single battery, and the control device 4 is configured to calculate the SOC and make a balancing judgment based on the collected information.

[0266] The above-mentioned embodiments of the present disclosure add a temperature compensation mechanism, taking into account the impact of temperature changes on battery characteristics, thereby improving the accuracy of estimation.

[0267] The above embodiment of the present disclosure adds a temperature sensor to the battery management system to monitor the battery temperature in real time. The above embodiment of the present disclosure can adjust the parameters of the open circuit voltage (OCV) and the ampere-hour integration method according to temperature changes to reduce the impact of temperature on SOC estimation.

[0268] The above-mentioned embodiments of the present disclosure aim to address the deficiencies in related technologies, improve the performance and reliability of energy storage systems, and provide strong support for the stable operation of power grids and the efficient use of renewable energy by adopting advanced monitoring technologies, optimized balancing management strategies, enhanced system reliability design, intelligent charging and discharging management algorithms, and efficient communication and integration solutions.

[0269] According to another aspect of the present disclosure, a computer program product is provided, including a computer program, wherein when the computer program is executed by a processor, the control method as described in any of the above embodiments is implemented.

[0270] According to another aspect of the present disclosure, a computer-readable storage medium is provided, wherein the computer-readable storage medium stores computer instructions, and when the instructions are executed by a processor, the control method as described in any of the above embodiments is implemented.

[0271] The computer-readable storage medium of the present disclosure may be implemented as a non-transitory computer-readable storage medium.

[0272] Those skilled in the art will appreciate that the embodiments of the present disclosure may be provided as methods, devices, or computer program products. Therefore, the present disclosure may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present disclosure may take the form of a computer program product implemented on one or more computer-usable non-transient storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0273] The present disclosure is described with reference to flowcharts and / or block diagrams of methods, devices (systems) and computer program products according to embodiments of the present disclosure. It should be understood that each process and / or block in the flowchart and / or block diagram and the combination of processes and / or blocks in the flowchart and / or block diagram can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0274] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0275] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process in the computer or other programmable device. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0276] The control device, voltage acquisition module, voltage difference determination module and battery balancing module described above may be implemented as a general purpose processor, a programmable logic controller, 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 or any appropriate combination thereof for performing the functions described in the present disclosure.

[0277] Those skilled in the art will appreciate that all or part of the steps of the above-described embodiment method of the present disclosure may be accomplished by hardware, and the hardware may be implemented as a general-purpose processor, a programmable logic controller, a digital signal processor, an application-specific integrated circuit, a field programmable gate array or other programmable logic device, a discrete gate or transistor logic device, a discrete hardware component, or any appropriate combination thereof for executing the method described in the present disclosure.

[0278] So far, the present disclosure has been described in detail. In order to avoid obscuring the concept of the present disclosure, some details known in the art are not described. Based on the above description, those skilled in the art can fully understand how to implement the technical solution disclosed here.

[0279] A person skilled in the art will understand that all or part of the steps to implement the above embodiments may be accomplished by hardware, or may be accomplished by instructing the relevant hardware through a program, and the program may be stored in a non-transitory computer-readable storage medium, and the above-mentioned storage medium may be a read-only memory, a disk or an optical disk, etc.

[0280] The description of the present disclosure is given for the purpose of illustration and description, and is not intended to be exhaustive or to limit the present disclosure to the disclosed form. Many modifications and variations will be apparent to those of ordinary skill in the art. The embodiments are selected and described in order to better illustrate the principles and practical applications of the present disclosure, and to enable those of ordinary skill in the art to understand the present disclosure and thereby design various embodiments with various modifications suitable for specific uses.

Claims

1. A control method for a battery management system, comprising: For each battery module in a battery device, obtaining a maximum value, a minimum value, and an average value of the voltages of all cells in the battery module, wherein the battery device includes a plurality of battery modules; Determine a first voltage difference according to an absolute value of a difference between the minimum value and the average value; Determining a second voltage difference according to an absolute value of a difference between the maximum value and the average value; The battery module is subjected to battery balancing according to the first voltage difference and the second voltage difference, wherein the battery balancing includes at least one of active battery balancing and passive battery balancing.

2. The control method of the battery management system according to claim 1, wherein: The performing battery balancing on the battery module according to the first voltage difference and the second voltage difference comprises: Taking the maximum value of the first voltage difference and the second voltage difference as the voltage difference of the battery module; Determining a balancing mark of the battery module according to the magnitude of the pressure difference of the battery module; The battery module is subjected to battery balancing according to the balancing identifier and the magnitude relationship between the first voltage difference and the second voltage difference.

3. The control method of the battery management system according to claim 2, wherein: Determining the equalization mark of the battery module according to the magnitude of the pressure difference of the battery module includes: When the voltage difference of the battery module is greater than a first voltage threshold, using a first balancing mark as a balancing mark of the battery module; When the voltage difference of the battery module is not greater than the first voltage threshold and greater than the second voltage threshold, a second balancing mark is used as a balancing mark of the battery module, wherein the second voltage threshold is less than the first voltage threshold; When the voltage difference of the battery module is not greater than the second voltage threshold, the third balancing mark is used as the balancing mark of the battery module.

4. The control method of the battery management system according to claim 3, wherein: The performing battery balancing on the battery module according to the balancing identifier and the magnitude relationship between the first voltage difference and the second voltage difference includes: When the balancing mark of the battery module is the first balancing mark and the first voltage difference is greater than the second voltage difference, active charging balancing is performed on the battery module, and the balancing channel of the battery module is recorded as the charging channel.

5. The control method of the battery management system according to claim 4, wherein: The performing battery balancing on the battery module according to the balancing identifier and the magnitude relationship between the first voltage difference and the second voltage difference further includes: When the balancing mark of the battery module is the first balancing mark and the first voltage difference is not greater than the second voltage difference, active discharge balancing and passive discharge balancing are performed on the battery module, and the balancing channel of the battery module is recorded as a discharge channel.

6. The control method of the battery management system according to claim 5, wherein: The performing battery balancing on the battery module according to the balancing identifier and the magnitude relationship between the first voltage difference and the second voltage difference further includes: Count the number of discharge channels and the number of charge channels in the battery device, where one balancing channel corresponds to one battery module; In a case where the number of the discharge channels is greater than the number of the charge channels, a first number of battery modules are converted for passive balancing, wherein the first number is a difference between the number of the discharge channels and the number of the charge channels.

7. The control method of a battery management system according to any one of claims 3 to 6, wherein: The performing battery balancing on the battery module according to the balancing identifier and the magnitude relationship between the first voltage difference and the second voltage difference includes: When the balancing mark of the battery module is the second balancing mark and the first voltage difference is greater than the second voltage difference, a charging reminder message is displayed and a balancing enable switch is turned off.

8. The control method of a battery management system according to any one of claims 3 to 6, wherein: The performing battery balancing on the battery module according to the balancing identifier and the magnitude relationship between the first voltage difference and the second voltage difference includes: When the balancing mark of the battery module is the second balancing mark and the first voltage difference is not greater than the second voltage difference, passive balancing is performed on the battery module.

9. The control method of a battery management system according to any one of claims 3 to 6, wherein: The performing battery balancing on the battery module according to the balancing identifier and the magnitude relationship between the first voltage difference and the second voltage difference includes: When the balancing mark of the battery module is the third balancing mark, the balancing enabling switch is turned off.

10. The control method of a battery management system according to any one of claims 2 to 6, wherein: Determining the equalization mark of the battery module according to the magnitude of the pressure difference of the battery module includes: When the voltage difference of the battery module is greater than the first voltage threshold value within a first predetermined time period, using the first balancing mark as the balancing mark of the battery module; When the voltage difference of the battery module is not greater than the first voltage threshold and greater than the second voltage threshold within a first predetermined time, a second balancing mark is used as a balancing mark of the battery module, wherein the second voltage threshold is less than the first voltage threshold; When the voltage difference of the battery module is not greater than the second voltage threshold within a first predetermined period of time, the third balancing mark is used as the balancing mark of the battery module.

11. The control method of a battery management system according to any one of claims 1 to 6, further comprising: Determining whether the battery module is being charged or discharged; When the battery module is not being charged or discharged, performing the step of performing battery balancing on the battery module according to the first voltage difference and the second voltage difference; When the battery module is being charged and discharged, the balancing enable switch is turned off.

12. The control method of the battery management system according to any one of claims 1 to 6, further comprising: The state of charge SOC of the battery device is calculated.

13. The control method of the battery management system according to claim 12, wherein: The calculating the state of charge SOC of the battery device comprises: When the battery device is charged and discharged for the first time, the open circuit SOC is calculated using the open circuit voltage; When the difference between the open circuit SOC and the last recorded SOC is smaller than a predetermined threshold, the open circuit SOC is used as the initial SOC.

14. The control method of the battery management system according to claim 12, wherein: The calculating the state of charge SOC of the battery device comprises: When the battery device is not charged or discharged for the first time, the current SOC is calculated using the ampere-hour integral; When the stationary time does not exceed the second predetermined time, the current SOC is used as the initial SOC.

15. The control method of the battery management system according to claim 14, wherein: The calculating the state of charge SOC of the battery device further includes: When the static time exceeds a second predetermined time, calculating a calibration SOC using the open circuit voltage; When the difference between the calibrated SOC and the current SOC is less than a predetermined threshold, taking the current SOC as an initial SOC; When the difference between the calibrated SOC and the current SOC is not less than a predetermined threshold, the calibrated SOC is used as an initial SOC.

16. A control device comprising: a voltage acquisition module configured to acquire, for each battery module in a battery device, a maximum value, a minimum value and an average value of the voltages of all cells in the battery module, wherein the battery device includes a plurality of battery modules; A voltage difference determination module, which determines a first voltage difference according to an absolute value of a difference between the minimum value and the average value; and determines a second voltage difference according to an absolute value of a difference between the maximum value and the average value; The battery balancing module is configured to perform battery balancing on the battery module according to the first voltage difference and the second voltage difference, wherein the battery balancing includes at least one of active battery balancing and passive battery balancing.

17. A control device comprising: a memory configured to store instructions; and The processor is configured to execute the instructions so that the control device implements the control method as described in any one of claims 1-15.

18. A battery management system, comprising the control device according to claim 16 or 17.

19. The battery management system according to claim 18, further comprising a voltage acquisition device, an active balancing device and a passive balancing device.

20. A computer-readable storage medium, wherein: The computer-readable storage medium stores computer instructions, and when the instructions are executed by a processor, the control method according to any one of claims 1 to 15 is implemented.

21. A computer program product comprising a computer program, wherein: When the computer program is executed by a processor, the control method according to any one of claims 1 to 15 is implemented.

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