Current calculation method and device, battery management system, battery, electric device

Abstract

The application relates to the technical field of batteries, and discloses a current calculation method and device, a battery management system, a battery and a power utilization device. The method comprises the following steps: acquiring a first current value of a current loop according to an acquired voltage signal, wherein the voltage signal is a voltage signal corresponding to a current access unit connected to the current loop; acquiring a sampling reference voltage based on an acquired reference source signal, and acquiring an offset corresponding to the first current value according to the sampling reference voltage; acquiring a current calibration parameter corresponding to a battery management system; and calculating a current of the battery management system according to the first current value, the offset and the current calibration parameter. The current calculation method and device, the battery management system, the battery and the power utilization device provided by the application can overcome problems caused by differences between parameters of devices themselves and error problems caused by temperature drift when detecting a current, and effectively improve current acquisition precision.

Description

Technical Field

[0001] This application relates to the field of battery technology, and in particular to a current calculation method and apparatus, a battery management system, a battery, and an electrical device. Background Technology

[0002] Current current acquisition schemes typically use a shunt connected in series to the current loop. The voltage signal across the shunt is then connected to an operational amplifier, and the amplified signal is input to the analog input port of an analog-to-digital converter to obtain a digital signal. The current value is then calculated by software.

[0003] However, in the process of implementing the embodiments of this application, the inventors discovered that the related technologies are prone to errors in actual data when collecting current due to device parameter errors, temperature drift, etc., which leads to poor accuracy of the detected current. Summary of the Invention

[0004] The embodiments of this application at least partially improve the above-mentioned problems and improve the accuracy of the current detected in the battery management system.

[0005] To solve the above-mentioned technical problems, one technical solution adopted in the embodiments of this application is:

[0006] In a first aspect, embodiments of this application provide a current calculation method applied to a battery management system. The battery management system includes a current access unit and an operational amplifier. The current access unit is connected in series to a current loop, and the operational amplifier is connected to the current access unit. The method includes: obtaining a first current value of the current loop based on a collected voltage signal; obtaining a sampling reference voltage based on a collected reference source signal, and obtaining an offset corresponding to the first current value based on the sampling reference voltage; obtaining current calibration parameters corresponding to the battery management system; and calculating the current of the battery management system based on the first current value, the offset, and the current calibration parameters. The voltage signal is the voltage signal corresponding to the current access unit. The voltage signal can be amplified by the operational amplifier, and the first current value can be obtained by calculating the amplified voltage with the resistance of the current access unit. The reference source signal provides a stable reference voltage, which can be used to calibrate the first current value.

[0007] In some embodiments, obtaining the first current value of the current loop based on the acquired voltage signal includes: obtaining the voltage signal after the voltage signal has been amplified by an operational amplifier; obtaining the resistance of the current access unit; and calculating the first current value of the current loop based on the amplified voltage signal and the resistance.

[0008] In some embodiments, obtaining a sampling reference voltage based on a acquired reference source signal and obtaining an offset corresponding to the first current value based on the sampling reference voltage includes: acquiring a reference source signal output by an operational amplifier; obtaining a sampling reference voltage based on the reference source signal; obtaining a preset reference voltage reference value based on a received debugging instruction; and calculating the difference between the reference voltage reference value and the sampling reference voltage, wherein the difference is the offset corresponding to the first current value.

[0009] In some embodiments, calculating the current of the battery management system based on the first current value, the offset, and the current calibration parameters includes: obtaining a current gain value and a current bias value based on the current calibration parameters; summing the first current value and the offset, and multiplying the sum by the current gain value to obtain a compensation current; and calculating the sum of the compensation current and the current bias value, wherein the sum is the current of the battery management system.

[0010] In some embodiments, obtaining the current gain value and current bias value based on the current calibration parameters includes: obtaining at least three set currents and obtaining the sampling currents corresponding to the at least three set currents respectively; and calculating the current gain value and current bias value of the battery management system based on the set currents and the sampling currents.

[0011] In some embodiments, the set current includes a first set current I1, a second set current I2, and a third set current I3, and the sampled current includes a first sampled value AD1, a second sampled value AD2, and a third sampled value AD3. The step of calculating the current gain and current bias values ​​of the battery management system based on the set current and the sampled current includes: calculating parameters according to the following formula. and

[0012]

[0013]

[0014]

[0015]

[0016] According to the above The The and stated Calculate the current gain value and the current bias value. Wherein, the current gain value... The current bias value

[0017] In a second aspect, embodiments of this application provide a current calculation device applied to a battery management system. The battery management system includes a current access unit and an operational amplifier. The current access unit is connected in series to a current loop, and the operational amplifier is connected to the current access unit. The device includes: a first acquisition module, configured to acquire a first current value of the current loop based on a collected voltage signal, wherein the voltage signal is a voltage signal corresponding to the current access unit connected to the current loop; a second acquisition module, configured to acquire a sampling reference voltage based on a collected reference source signal, and acquire an offset corresponding to the first current value based on the sampling reference voltage; a third acquisition module, configured to acquire current calibration parameters corresponding to the battery management system; and a calculation module, configured to calculate the current of the battery management system based on the first current value, the offset, and the current calibration parameters.

[0018] In a third aspect, embodiments of this application provide a battery management system, comprising: a current access unit connected in series to a current loop; an operational amplifier connected to the current access unit; at least two analog-to-digital converters (ADCs) respectively connected to the operational amplifier; and a controller connected to the at least two ADCs. The controller includes: at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, which, when executed by the at least one processor, enable the at least one processor to perform the current calculation method described above.

[0019] In a fourth aspect, embodiments of this application provide a battery, including a battery cell and a battery management system as described above. The battery management system is used to manage the charging and discharging of the battery cell.

[0020] In a fifth aspect, embodiments of this application provide an electrical device including a load and a battery as described above. The battery is used to supply power to the load.

[0021] Unlike related technologies, this application provides a current calculation method and apparatus, a battery management system, a battery, and an electrical device. The method obtains a first current value for a current loop based on a collected voltage signal (the voltage signal corresponding to the current access unit connected to the current loop). Then, a sampling reference voltage is obtained based on a collected reference source signal, and an offset corresponding to the first current value is obtained based on this sampling reference voltage. Current calibration parameters of the battery management system are also obtained. Finally, the current of the battery management system is calculated based on the first current value, the current calibration parameters, and the offset. The current calculation method and apparatus, battery management system, battery, and electrical device provided in this application can overcome accuracy problems caused by differences in device parameters and errors caused by temperature drift when detecting current, effectively improving the accuracy of current acquisition. Attached Figure Description

[0022] One or more embodiments are illustrated by way of example with reference to the accompanying drawings. These illustrations do not constitute a limitation on the embodiments. Elements having the same reference numerals in the drawings are denoted as similar elements. Unless otherwise stated, the figures in the drawings are not to be limited by scale.

[0023] Figure 1 This is a schematic diagram illustrating an application scenario provided in an embodiment of this application;

[0024] Figure 2 This is a schematic diagram of the controller for the current calculation method provided in this application embodiment;

[0025] Figure 3 This is a flowchart of a current calculation method provided in an embodiment of this application;

[0026] Figure 4 This is a reference graph showing the current versus temperature variation curves of the 12-bit analog-to-digital converter provided in this application embodiment before compensation is applied.

[0027] Figure 5 This is a reference graph showing the current versus temperature variation curves of the 12-bit analog-to-digital converter provided in this application embodiment after compensation has been added.

[0028] Figure 6 This is a reference graph showing the current versus temperature variation curves of the 16-bit analog-to-digital converter provided in this application embodiment before compensation is applied.

[0029] Figure 7 This is a reference graph showing the current versus temperature variation curves of the 16-bit analog-to-digital converter provided in this application embodiment after compensation has been added.

[0030] Figure 8 This is a schematic diagram of the structure of a current calculation device provided in an embodiment of this application. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0032] It should be noted that, unless otherwise specified, the various features in the embodiments of this application can be combined with each other, all of which are within the protection scope of this application. Furthermore, although functional modules are divided in the device schematic diagram and a logical order is shown in the flowchart, in some cases, the steps shown or described may be performed in a different order than the module division in the device schematic diagram or the order in the flowchart.

[0033] Unless otherwise defined, all technical and scientific terms used in this specification have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the scope of this application. The term "and / or" as used in this specification includes any and all combinations of one or more of the associated listed items.

[0034] The current calculation method and apparatus provided in this application can improve the problem of poor accuracy of detected current values ​​caused by inconsistent device parameters and different ambient temperatures. This application obtains current calibration parameters in advance, acquires the reference source signal of the operational amplifier, calculates its offset in real time, obtains a compensation value after conversion, and finally adds this compensation value to the current signal. The final current is then calculated based on the current calibration parameters, thereby achieving current compensation, reducing errors, and improving current accuracy.

[0035] The current calculation method and apparatus described above can be applied to the current detection process of a BMS (Battery Management System). For example... Figure 1 As shown, Figure 1This application scenario, provided by an embodiment of the present application, includes a load 10, a battery pack 20, and a host computer 30. The battery pack 20 is connected to both the load 10 and the host computer 30. The battery pack 20 includes a battery module 21 and a battery management system 22, with the battery module 21 connected to the battery management system 22. The battery module 21 includes cells connected in series and / or in parallel. The battery management system 22 is used to collect operating parameters of the battery module 21, such as charging / discharging current, voltage, and temperature, and to control the charging / discharging of the battery module 21 based on the collected operating parameters. It can also detect battery status parameters, such as the state of charge of the battery module 21, based on the collected operating parameters. When overcharging or overcurrent occurs, the battery management system 22 is also used to control the on / off state of the charging / discharging switch, thereby controlling the charging or discharging of the battery module 21. Specifically, the battery management system 22 can be a circuit board, and the charge / discharge switch can be installed on the circuit board. The circuit board is electrically connected to the battery module 21. The circuit board can be electrically connected to the battery module 21 through an adapter board, or it can be directly electrically connected to the positive and negative terminals of the battery cells in the battery module 21, thereby collecting the operating parameters of the battery module 21.

[0036] The battery management system 22 includes a controller 221, a current input unit 222, an operational amplifier 223, and an analog-to-digital converter 224. Two analog-to-digital converters 224 can be configured. The current input unit 222 receives a current signal and converts it into a voltage signal. This voltage signal is transmitted to the operational amplifier 223, which amplifies the voltage signal and inputs it to the analog input port of one of the analog-to-digital converters 224. The analog-to-digital converter 224 processes the voltage signal and outputs a digital signal to the controller 221. The other analog-to-digital converter 224 receives a reference source signal from the operational amplifier 223 through its analog input port, processes the reference source signal, and outputs another digital signal to the controller 221. The controller 221 calculates the current of the battery module 21 based on the two received digital signals. The reference source signal refers to the signal output from the reference source input pin of the operational amplifier 223. This reference source input pin can be connected to a reference voltage source, which is used to ensure a stable voltage value as a reference voltage.

[0037] The current input unit 222 can be composed of a shunt and a voltage output port. The shunt can be connected in series to the current loop in the battery module 21, and the voltage signal at both ends of the shunt is connected to the operational amplifier 223 through the voltage output port. The current input unit 222 obtains a current signal from the battery module 21. When the current signal flows through the shunt, it can collect the voltage at both ends of the shunt to obtain the voltage signal. This voltage signal can be amplified by the operational amplifier 223 to obtain the amplified voltage. The resistance of the shunt is also obtained, and then the quotient of the amplified voltage and the resistance is calculated to obtain the amplified current signal. This current signal is converted into a digital current signal after passing through the analog-to-digital converter 224.

[0038] When the analog-to-digital converter 224 processes the received reference source signal, it can calculate the reference current based on the reference source signal and convert the reference current into its corresponding digital signal. Thus, the compensation value of the converted current, i.e., the offset mentioned below, can be obtained based on the reference current.

[0039] In the above application scenario, by adding the reference source signal of the detection operational amplifier 223, the current deviation caused by temperature and other reasons is calculated, and the calculated current deviation is compensated into the currently collected current, thereby realizing current compensation and improving the current acquisition accuracy.

[0040] The load 10 can be a high-precision load cell, used to collect high-precision current and accurately adjust power, providing a stable discharge current. The host computer 30 is communicatively connected to the battery pack 20, and works with the battery pack 20 to perform functions such as voltage, current, and temperature monitoring, leakage current monitoring, remaining capacity calculation, and alarm alerts. The host computer 30 includes, but is not limited to, desktop computers, laptops, tablets, and smartphones.

[0041] In one embodiment of this application, such as Figure 2 As shown, the controller 221 includes: one or more processors 2211 and a memory 2212. Figure 2 Take a processor 2211 as an example.

[0042] The processor 2211 and the memory 2212 can be connected via a bus or other means. Figure 2 Taking the example of a connection between China and Israel via a bus.

[0043] The memory 2212, as a non-volatile computer-readable storage medium, can be used to store non-volatile software programs, non-volatile computer-executable programs, and modules, such as the program instructions / modules corresponding to the current calculation method in the embodiments of this application (e.g., attached...). Figure 8(The various modules shown). The processor 2211 executes various functional applications and data processing of the battery management system by running non-volatile software programs, instructions, and modules stored in the memory 2212, that is, it implements the current calculation method of the following method embodiment.

[0044] The one or more modules are stored in the memory 2212. When executed by the one or more processors 2211, they perform the current calculation method in any of the following method embodiments, for example, they perform the following descriptions. Figure 3 The method steps in the text are to achieve the following: Figure 8 The functionality of the modules within.

[0045] In one embodiment of this application, the battery management system 22 may further include a display module, a wireless communication module, a data acquisition module, and electrical equipment. This battery management system 22 can be used for intelligent management and maintenance of the battery module 21, preventing overcharging and over-discharging of the battery module 21, monitoring the status of the battery module 21, and extending the service life of the battery module 21. It detects the voltage, current, and temperature of the batteries in the battery module 21 using sensors, and also performs leakage monitoring, calculates remaining capacity, and provides alarm reminders. The sensors include the aforementioned current access unit 222, which may specifically be a shunt, etc.

[0046] The battery management system 22 executes the current calculation method through the controller 221, which effectively improves the problems caused by the difference in the parameters of the device itself and the error caused by temperature during the current detection process of the battery management system 22, improves the current detection accuracy, and can provide reliable data input for calculating the state of charge, thereby improving the calculation accuracy of the state of charge and effectively enhancing the product competitiveness.

[0047] The above-mentioned products can perform the methods provided in the embodiments of this application, and have the corresponding functional modules and beneficial effects of performing the methods. Please refer to the methods provided in the embodiments of this application.

[0048] Based on the above application scenarios, the following embodiments will specifically illustrate the current calculation method of this application.

[0049] like Figure 3 As shown in the figure, this application provides a current calculation method, which can be applied to the aforementioned battery management system and can be executed by the aforementioned controller. The battery management system includes a current input unit and an operational amplifier. The current input unit is connected in series to a current loop, and the operational amplifier is connected to the current input unit. The current calculation method may include the following steps:

[0050] Step S11: Based on the collected voltage signal, obtain the first current value of the current loop, wherein the voltage signal is the voltage signal corresponding to the current access unit connected to the current loop.

[0051] The voltage signal is the voltage signal of the current access unit in the current loop, which can control the battery pack to discharge the load. After the current access unit is connected in series in the current loop, the voltage signal of the current access unit is acquired by an analog-to-digital converter. The current access unit can be a shunt, and the voltage signal can be the voltage difference across the shunt. After the analog-to-digital converter acquires the voltage signal, it obtains the corresponding resistance value of the shunt and calculates the current value corresponding to the voltage signal and the resistance value based on Ohm's law. This current value is the first current value.

[0052] Optionally, obtaining the first current value of the current loop based on the acquired voltage signal includes: acquiring the voltage signal amplified by an operational amplifier; acquiring the resistance of the current access unit; and calculating the first current value of the current loop based on the amplified voltage signal and the resistance. The voltage signal amplified by the operational amplifier is an analog signal, and the first current value calculated based on the amplified voltage signal and the resistance also corresponds to an analog signal. Through analog-to-digital conversion, the analog signal of the current is converted into a digital signal, thereby obtaining the first current value. This embodiment of the application improves the sampling accuracy of the first current value by amplifying the acquired voltage signal using an operational amplifier.

[0053] Optionally, the battery management system may trigger the current calculation method of this application after receiving a current acquisition command sent by the host computer.

[0054] Step S12: Obtain the sampling reference voltage based on the acquired reference source signal, and obtain the offset corresponding to the first current value according to the sampling reference voltage.

[0055] The reference source signal refers to the signal output from the reference source input pin of the operational amplifier. This pin can be connected to a reference voltage source, which is used to ensure a stable voltage value as a reference voltage. Typically, the acquired current signal is input to an analog-to-digital converter via the operational amplifier. However, operational amplifiers are prone to errors, partly due to inherent errors in the circuit components themselves, and partly due to errors during the measurement process, including errors in the measuring elements, power supply voltage, and measuring instruments. For example, temperature-induced zero-point drift, such as the aging of components causing output voltage drift with temperature changes, is addressed in this embodiment by acquiring the reference source signal from the operational amplifier to correct errors caused by temperature drift in the components.

[0056] Acquiring the reference source signal includes obtaining the reference source signal from an operational amplifier. This reference source signal is an analog signal. The reference source signal is then input to an analog-to-digital converter (ADC), which processes the reference source signal and outputs a digital signal. This digital signal represents the actual value of the reference voltage, which is the voltage value collected during the period when the battery pack discharges to the load, i.e., the sampling reference voltage.

[0057] It should be noted that both the voltage signal and the reference source signal mentioned above can be acquired by an analog-to-digital converter. They can be acquired simultaneously or in any order.

[0058] The offset is used to compensate for the first current value. Obtaining the offset corresponding to the first current value based on the sampled reference voltage includes: obtaining a preset reference voltage base value according to the received debugging command; calculating the difference between the reference voltage base value and the sampled reference voltage, where the difference is the offset. The preset reference voltage base value is pre-acquired and can be acquired when acquiring the current calibration parameters described below. The method for acquiring the reference voltage base value is similar to the method described above for acquiring the sampled reference voltage from the reference source signal; the main difference lies in the different operating conditions during signal acquisition. By calculating the offset, the problem of current error caused by temperature drift of components due to different ambient temperatures can be improved.

[0059] Step S13: Obtain the current calibration parameters corresponding to the battery management system.

[0060] As is known, due to the inconsistency of device parameters, even for the same type of component, differences in parameters may exist between different production batches. Furthermore, differences in parameters may also exist between different types of components within the same production batch. This results in poor accuracy of the sampled current values. Therefore, this embodiment of the application calibrates the current using a preset algorithm to obtain current calibration parameters corresponding to different types of components, and categorizes and archives the obtained current calibration parameters according to the type and batch of the component.

[0061] In one embodiment of this application, the method further includes acquiring current calibration parameters. Acquiring the current calibration parameters includes: acquiring at least three set currents, and acquiring sampled currents corresponding to the at least three set currents respectively; calculating a current gain value and a current bias value of the battery management system based on the set currents and the sampled currents. The current gain value and the current bias value serve as the current calibration parameters.

[0062] The at least three set currents can be obtained from debugging commands sent by the host computer. One debugging command can correspond to one set current, or one debugging command can include multiple set currents. The set currents are analog values, manually set, and can be set on the load. The host computer then sends the set currents to the battery management system. Alternatively, the host computer and the load can communicate, in which case the load can directly send the set currents to the host computer. Or, the host computer and the load can not communicate; in this case, the set currents are set on the load and then manually input to the host computer.

[0063] The sampling current corresponding to the at least three set currents refers to a sampling current corresponding to each set current. The sampling current is the actual current signal collected, which can be obtained by obtaining the first current value in step S11 above.

[0064] After obtaining the set current and the sampled current, the current gain value and the current bias value can be calculated using a preset algorithm, such as the least squares method.

[0065] To ensure the accuracy and reliability of the calculated current gain and current bias values, at least three set currents and at least three corresponding sampled currents are required. These at least three set currents are based on the discharge current. For example, if three set currents are included, they typically represent the current values ​​at three points: zero, the first negative current point, and the second negative current point. The current value at zero refers to the current sampled when the circuit is neither discharging nor charging. The current values ​​at the first and second negative current points represent the two currents sampled during the circuit's discharge process. In addition to setting three current points, more current points can be set, each corresponding to a set current. For example, if five set currents are included, they typically represent the current values ​​at five points, such as zero and the other four negative current points, etc. In some embodiments, when the battery pack is charged using a set voltage, the current corresponding to a positive current point can also be used as the set current, where the current corresponding to the positive current point refers to the current sampled during the circuit's charging process. The above uses the current obtained during the discharge process as the negative current point and the current obtained during the charging process as the positive current point. It should be noted that the current obtained during the discharge process can also be used as the positive current point and the current obtained during the charging process as the negative current point.

[0066] It should be noted that the above-mentioned at least three set currents can be three, and correspondingly, the sampling current also has three values. This can reduce the amount of calculation and ensure that the final calculated current gain value and current bias value are accurate and reliable.

[0067] For example, the set current includes a first set current I1, a second set current I2, and a third set current I3, and the sampling current includes a first sampling value AD1, a second sampling value AD2, and a third sampling value AD3. The high-precision load instrument is discharged using the battery pack. During this process, the host computer sends a first debugging command to the battery management system, which includes the first set current I1 and acquires the first sampling value AD1; the host computer also sends a second debugging command to the battery management system, which includes the second set current I2 and acquires the second sampling value AD2; the host computer also sends a third debugging command to the battery management system, which includes the third set current I3 and acquires the third sampling value AD3. Then, the parameters are calculated using the least squares formula. and

[0068]

[0069]

[0070]

[0071]

[0072] Based on the above The The and stated Calculate the current gain value and the current bias value.

[0073] Wherein, the current gain value The current bias value

[0074] Therefore, based on the linear relationship between current and AD value, the current value I can be obtained as I = Gain * AD + Offset.

[0075] Through the above steps, the current calibration parameters can be obtained. For different battery products, the current calibration parameters of such products can be obtained in advance in the above manner. The current calibration parameters can solve the problem of poor current accuracy caused by the individual parameter differences of the device itself.

[0076] Step S14: Calculate the current of the battery management system based on the first current value, the offset, and the current calibration parameters.

[0077] The current of the battery management system can be calculated using the following formula:

[0078] Current Ireal = Gain * (AD + ΔVref) + Offset

[0079] Wherein, ΔVref is the offset, AD corresponds to the first current value, Gain is the current gain value, and Offset is the current bias value. ΔVref can be calculated by taking the difference between the reference voltage and the sampled reference voltage, which is the voltage offset. Based on Ohm's law, the current offset is calculated using this voltage offset and the resistance value of the operational amplifier. Then, the digital signal corresponding to the current offset is obtained through analog-to-digital conversion, thus yielding ΔVref. The resistance value of the operational amplifier can be determined based on the resistance at the signal input terminal of the operational amplifier.

[0080] The current calculation method provided in this application can effectively solve the current accuracy problem of energy storage systems under the same hardware cost conditions. It can effectively improve the current acquisition accuracy across the entire temperature range, providing reliable data input for the SOC in harsh environments, thereby improving SOC accuracy and effectively enhancing product competitiveness.

[0081] The following is through Figures 4 to 7 The current calculation method provided in the embodiments of this application is verified. Figure 4 and Figure 5 This is a reference graph showing the current versus temperature curves collected over the full temperature range for a 12-bit analog-to-digital converter. Figure 6 and Figure 7 This is a reference graph showing the current versus temperature curves of a 16-bit analog-to-digital converter over the entire temperature range. For example, Figure 4 and Figure 5 The figures show the zero-drift current of a 12-bit analog-to-digital converter before and after compensation, respectively. Baltemp represents the temperature curve, Current represents the current curve, and Baltemp1 and Baltemp2 are the ambient temperatures collected by two temperature sensors. These two temperature sensors can be set on the circuit board and can collect the temperature of the circuit board in the working state. Figures 4 to 7 The numbers on the horizontal axis represent the data points corresponding to the temperature and current acquisition times, which can be understood as the time during parameter acquisition, and the unit can be seconds. The numbers on the left side of the vertical axis represent temperature, and the unit can be degrees Celsius. The numbers on the right side of the vertical axis represent current, and the unit can be amperes. Figure 4 and Figure 6 In this case, because current compensation was not considered, the detected current fluctuates with temperature changes. Figure 5 and Figure 7 In this system, after adding compensation to the current, the current remains basically constant as the temperature changes, and does not fluctuate with temperature fluctuations.

[0082] like Figure 8As shown in the figure, this application embodiment provides a current calculation device 40 applied to a battery management system. The battery management system includes a current access unit and an operational amplifier. The current access unit is connected in series to a current loop, and the operational amplifier is connected to the current access unit. The current calculation device 40 includes a first acquisition module 41, a second acquisition module 42, a third acquisition module 43, and a calculation module 44. The first acquisition module 41 is used to acquire a first current value of the current loop based on a collected voltage signal, wherein the voltage signal is the voltage signal corresponding to the current access unit connected to the current loop. The second acquisition module 42 is used to acquire a sampling reference voltage based on a collected reference source signal, and acquire an offset corresponding to the first current value based on the sampling reference voltage. The third acquisition module 43 is used to acquire current calibration parameters corresponding to the battery management system. The calculation module 44 is used to calculate the current of the battery management system based on the first current value, the offset, and the current calibration parameters.

[0083] The first acquisition module 41, the second acquisition module 42, and the third acquisition module 43 can be connected to the calculation module 44 respectively. The three acquisition modules input their respective first current values, offsets, and current calibration parameters into the calculation module 44, thereby calculating the current of the battery management system through the calculation module 44.

[0084] It should be noted that the above-described current calculation device can execute the current calculation method provided in the embodiments of this application, and has the corresponding functional modules and beneficial effects of the method. Technical details not described in detail in this embodiment of the current calculation device can be found in the current calculation method provided in the embodiments of this application.

[0085] This application also provides a battery, which includes a battery cell and a battery management system as described above. The battery management system is used to manage the charging and discharging of the battery cell. During charging and discharging, the battery current can be detected based on the aforementioned current calculation method to obtain the battery's state of charge, etc.

[0086] This application embodiment also provides an electrical device, which includes a load and the aforementioned battery, the battery being used to supply power to the load.

[0087] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs.

[0088] Through the above description of the embodiments, those skilled in the art can clearly understand that each embodiment can be implemented using software and a general-purpose hardware platform, or of course, using hardware. Those skilled in the art will understand that all or part of the processes in the above embodiments can be implemented by a computer program instructing related hardware. The program can be stored in a computer-readable storage medium, and when executed, it can include the processes of the embodiments of the above methods. The storage medium can be a magnetic disk, optical disk, read-only memory (ROM), or random access memory (RAM), etc.

[0089] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and not to limit them; under the concept of this application, the technical features of the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations of different aspects of this application as described above, which are not provided in detail for the sake of brevity; although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or make equivalent substitutions for some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A method for calculating current, characterized in that, The method is applied to a battery management system, which includes a current input unit, an operational amplifier, at least two analog-to-digital converters (ADCs), and a controller. The current input unit is connected in series to a current loop. The operational amplifier is connected to the current input unit. The at least two ADCs are each connected to the operational amplifier. The controller is connected to the at least two ADCs. The method includes: Based on the acquired voltage signal, a first current value of the current loop is obtained, wherein the voltage signal is the voltage signal corresponding to the current access unit connected to the current loop; wherein, the voltage signal is amplified by an operational amplifier; the resistance of the current access unit is obtained; and the first current value of the current loop is calculated based on the amplified voltage signal and the resistance. A sampling reference voltage is obtained based on the acquired reference source signal, and an offset corresponding to the first current value is obtained based on the sampling reference voltage; wherein, the reference source signal refers to the signal output from the reference source input pin of the operational amplifier; the signal output from the reference source input pin is converted into a digital signal by the analog-to-digital converter, and the digital signal is used to represent the sampling reference voltage; the offset is the difference between the reference voltage reference value and the sampling reference voltage; Obtain the current calibration parameters corresponding to the battery management system; The current of the battery management system is calculated based on the first current value, the offset, and the current calibration parameters; wherein, the current gain value and the current bias value are obtained based on the current calibration parameters; the first current value and the offset are summed, and the product of the sum and the current gain value is calculated to obtain the compensation current; the sum of the compensation current and the current bias value is calculated, and the sum is the current of the battery management system.

2. The current calculation method according to claim 1, characterized in that, The process of obtaining a sampling reference voltage based on the acquired reference source signal and obtaining the offset corresponding to the first current value based on the sampling reference voltage includes: Obtain the reference source signal output from the operational amplifier; The sampling reference voltage is obtained based on the reference source signal; The preset reference voltage value is obtained based on the received debugging instructions; Calculate the difference between the reference voltage base value and the sampled reference voltage, where the difference is the offset corresponding to the first current value.

3. The current calculation method according to claim 1, characterized in that, The step of obtaining the current gain value and current bias value based on the current calibration parameters includes: Acquire at least three set currents, and acquire the sampling currents corresponding to the at least three set currents respectively; The current gain and current bias values ​​of the battery management system are calculated based on the set current and the sampled current.

4. The current calculation method according to claim 3, characterized in that, The set current includes a first set current I1, a second set current I2, and a third set current I3, and the sampled current includes a first sampled value AD1, a second sampled value AD2, and a third sampled value AD3. The step of calculating the current gain and current bias values ​​of the battery management system based on the set current and the sampled current includes: Calculate the parameters according to the following formula. , , and ; ； ； ； ； According to the above The above The above and stated Calculate the current gain value and the current bias value; Wherein, the current gain value Gain= ; The current bias value Offset= .

5. A current calculation device, characterized in that, The device includes: The first acquisition module is used to acquire the first current value of the current loop based on the acquired voltage signal, wherein the voltage signal is the voltage signal corresponding to the current access unit connected to the current loop; The second acquisition module is used to acquire a sampling reference voltage based on the acquired reference source signal, and to acquire the offset corresponding to the first current value according to the sampling reference voltage; The third acquisition module is used to acquire the current calibration parameters corresponding to the battery management system. A calculation module is used to calculate the current of the battery management system based on the first current value, the offset, and the current calibration parameters; The current calculation device is used to perform the current calculation method according to any one of claims 1 to 4.

6. A battery management system, characterized in that, Includes a controller, the controller comprising: At least one processor; and, A memory communicatively connected to the at least one processor; wherein, The memory stores instructions that can be executed by the at least one processor to enable the at least one processor to perform the method according to any one of claims 1 to 4.

7. A battery, characterized in that, It includes a battery cell and a battery management system as described in claim 6, wherein the battery management system is used to manage the charging and discharging of the battery cell.

8. An electrical device, comprising a load, characterized in that, It also includes the battery as described in claim 7, which supplies power to the load.

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