Calibration method, battery management system, battery device and electric equipment

Abstract

The application discloses a calibration method, a battery management system, a battery device and a power utilization equipment. The calibration method is characterized in that the method comprises the following steps: determining offset conditions of a first reference source based on an actual temperature and a first sampling voltage of the first reference source; determining offset conditions of a second reference source based on the actual temperature and a second sampling voltage of the second reference source; determining the first reference source as an offset reference source in the case that the first reference source exists offset and the second reference source does not exist offset; or determining a third reference source as the offset reference source in the case that the first reference source and the second reference source both exist offset; obtaining a voltage range corresponding to an average temperature and an average voltage of the first reference source, determining a voltage reference point based on the voltage range corresponding to the average temperature, determining a gain error based on a ratio of the average voltage and the voltage reference point, and compensating the first sampling voltage or the third sampling voltage based on the gain error.

Description

Technical Field

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

[0002] The Analog Front End (AFE) chip is responsible for acquiring and preprocessing critical analog signals from the battery. The sampling accuracy of the AFE chip directly affects the accuracy and effectiveness of battery equalization in the Battery Management System (BMS), thus impacting battery life, safety, and performance. Therefore, improving the sampling accuracy of the AFE chip is a pressing issue that needs to be addressed. Summary of the Invention

[0003] This application mainly provides a calibration method, a battery management system, a battery device, and an electrical device, which can improve sampling accuracy, enhance battery safety, and extend battery life.

[0004] The technical solution of this application is implemented as follows:

[0005] In a first aspect, embodiments of this application provide a calibration method, including:

[0006] Based on the actual temperature and the first sampling voltage of the first reference source, the offset of the first reference source is determined; and based on the actual temperature and the second sampling voltage of the second reference source, the offset of the second reference source is determined; the first sampling voltage and the second sampling voltage are both collected based on the third sampling voltage of the third reference source; wherein, the temperature range and the voltage range correspond one-to-one.

[0007] If the first reference source has an offset and the second reference source does not have an offset, the offset reference source is determined to be the first reference source; or, if both the first and second reference sources have offsets, the offset reference source is determined to be the third reference source.

[0008] The voltage range corresponding to the average temperature and the average voltage of the first reference source are obtained. Based on the voltage range corresponding to the average temperature, a voltage reference point is determined. The gain error is determined based on the ratio of the average voltage and the voltage reference point. The first sampling voltage or the third sampling voltage is compensated based on the gain error.

[0009] Through the above-described technical means, this application provides a calibration method. First, the offset of the first reference source is determined based on the actual temperature and the first sampling voltage of the first reference source, and the offset of the second reference source is determined based on the actual temperature and the second sampling voltage of the second reference source. This takes into account the impact of temperature changes on sampling accuracy, improving the accuracy and reliability of determining whether the reference source is offset. Second, since the voltages of the first and second reference sources are both collected from the third reference source, the offset reference source is determined by comprehensively considering the offsets of the first and second reference sources. This method can accurately identify the reference source that has offset. Finally, the gain error is determined based on the ratio of the average voltage to the voltage reference point, and the first or third sampling voltage is compensated based on the gain error. Since the offset of the second reference source is introduced as a reference for verification, the offset reference source can be accurately identified, further improving the accuracy of voltage sampling, enhancing the accuracy of subsequent sampling, improving battery safety and performance, and thus extending battery life.

[0010] In some embodiments, determining the offset of the first reference source based on the actual temperature and the first sampling voltage of the first reference source includes:

[0011] Determine the first preset voltage range corresponding to the actual temperature;

[0012] If the first sampling voltage is not within the first preset voltage range, the offset of the first reference source is determined to exist; or, if the first sampling voltage is within the first preset voltage range, the offset of the first reference source is determined to exist.

[0013] By employing the aforementioned technical means, a first preset voltage range is determined based on the actual temperature. By judging whether the first sampled voltage falls within this first preset voltage range, it is determined whether the first reference source exhibits any offset. This approach considers the influence of temperature on the voltage of the first reference source, thereby more accurately determining whether the first reference source exhibits any offset, and ultimately improving the accuracy of voltage sampling.

[0014] In some embodiments, determining the offset of the second reference source based on the actual temperature and the second sampling voltage of the second reference source includes:

[0015] Determine the second preset voltage range corresponding to the actual temperature;

[0016] If the second sampling voltage is not within the second preset voltage range, the offset of the second reference source is determined to exist; or, if the second sampling voltage is within the second preset voltage range, the offset of the second reference source is determined to exist.

[0017] By employing the aforementioned technical methods, a second preset voltage range is determined based on the actual temperature. By judging whether the second sampled voltage falls within this range, it is determined whether the second reference source exhibits any offset. This approach considers the influence of temperature on the voltage of the second reference source, thereby more accurately determining whether the second reference source exhibits any offset, and ultimately improving the accuracy of voltage sampling.

[0018] In some embodiments, obtaining the voltage range corresponding to the average temperature and the average voltage of the first reference source, and determining a voltage reference point based on the voltage range corresponding to the average temperature, includes:

[0019] The average voltage is determined based on the first sampled voltage and multiple historical voltages; the multiple historical voltages are the voltages collected by the first reference source at multiple times before the current time.

[0020] The average temperature is determined based on the actual temperature and multiple historical temperatures; the multiple historical temperatures are the temperatures collected at multiple times before the current time.

[0021] Determine the corresponding voltage range based on the temperature range of the average temperature;

[0022] The upper and lower limits of the voltage range corresponding to the average temperature are averaged to determine the voltage reference point.

[0023] Using the aforementioned techniques, the average voltage is determined based on the first sampled voltage and multiple historical voltages, and the average temperature is determined based on the actual temperature and multiple historical temperatures. Finally, the gain error is calculated and determined based on the average temperature and average voltage. This allows for the determination of the gain error based on multiple historical data points, improving the accuracy and reliability of the determined gain error, avoiding overcompensation, quickly recovering the reference source offset, and improving sampling efficiency.

[0024] In some embodiments, when the offset reference source is determined to be a first reference source, compensating the first sampled voltage based on the gain error includes:

[0025] Determine the compensation coefficient based on the gain error;

[0026] The first actual voltage is determined based on the product of the first sampled voltage and the compensation coefficient;

[0027] The first sampled voltage of the first reference source is compensated based on the first actual voltage.

[0028] Using the aforementioned techniques, with the offset reference source as the first reference source, a first actual voltage is determined based on the first sampling voltage and gain error, and the first sampling voltage of the first reference source is calibrated based on the first actual voltage. This allows for customized design of compensation logic, more accurately offsetting the offset and thus improving sampling efficiency.

[0029] In some embodiments, when the offset reference source is determined to be a third reference source, compensation for the third sampled voltage based on the gain error includes:

[0030] Determine the compensation coefficient based on the gain error;

[0031] The second actual voltage is determined based on the ratio of the third sampled voltage to the compensation coefficient;

[0032] The third sampling voltage of the third reference source is compensated based on the second actual voltage.

[0033] Using the aforementioned techniques, when the offset reference source is a third reference source, a second actual voltage is determined based on the third sampling voltage and gain error. The third sampling voltage of the third reference source is then calibrated based on this second actual voltage. This allows for customized design of compensation logic, more accurately offsetting the offset and thus improving sampling efficiency.

[0034] Secondly, embodiments of this application provide a battery management system, including:

[0035] The sampling circuit is used to acquire the actual temperature, the first sampling voltage of the first reference source, and the second sampling voltage of the second reference source; the first sampling voltage and the second sampling voltage are both acquired based on the third sampling voltage of the third reference source; wherein the temperature range corresponds one-to-one with the voltage range.

[0036] The controller is configured to determine the offset reference source as the first reference source when there is an offset in the first reference source and no offset in the second reference source; or, when there are offsets in both the first and second reference sources, determine the offset reference source as the third reference source; acquire the voltage range corresponding to the average temperature and the average voltage of the first reference source, and determine a voltage reference point based on the voltage range corresponding to the average temperature, determine the gain error based on the ratio of the average voltage and the voltage reference point, and compensate the first sampled voltage or the third sampled voltage based on the gain error.

[0037] Thirdly, embodiments of this application provide a battery device, including a battery and a battery management system as described in the second aspect.

[0038] Fourthly, embodiments of this application provide an electrical device, including the battery device as described in the third aspect.

[0039] It should be understood that the above general description and the following detailed description are merely exemplary and explanatory, and are not intended to limit the technical solutions of this application. Attached Figure Description

[0040] Figure 1A flowchart illustrating a calibration method provided in this application embodiment. Figure 1 ;

[0041] Figure 2 A schematic diagram of an AFE chip provided in this application embodiment. Figure 1 ;

[0042] Figure 3 A schematic diagram of an AFE chip provided in this application embodiment. Figure 2 ;

[0043] Figure 4 A schematic diagram of an AFE chip provided in this application embodiment. Figure 3 ;

[0044] Figure 5 A flowchart illustrating a calibration method provided in this application embodiment. Figure 2 ;

[0045] Figure 6 A flowchart illustrating a calibration method provided in this application embodiment. Figure 3 ;

[0046] Figure 7 A flowchart illustrating a calibration method provided in this application embodiment. Figure 4 ;

[0047] Figure 8 A flowchart illustrating a calibration method provided in this application embodiment. Figure 5 ;

[0048] Figure 9 A flowchart illustrating a calibration method provided in this application embodiment. Figure 6 ;

[0049] Figure 10 A flowchart illustrating a calibration method provided in this application embodiment. Figure 7 ;

[0050] Figure 11 A schematic diagram of the error curve of a calibration method provided in an embodiment of this application;

[0051] Figure 12 A schematic diagram of the composition structure of a battery management system provided in an embodiment of this application;

[0052] Figure 13 This is a schematic diagram of the composition structure of a battery device provided in an embodiment of this application;

[0053] Figure 14 This is a schematic diagram of the composition structure of an electrical device provided in an embodiment of this application. Detailed Implementation

[0054] In order to gain a more detailed understanding of the features and technical content of the embodiments of this application, the implementation of the embodiments of this application will be described in detail below with reference to the accompanying drawings. The accompanying drawings are for reference and illustration only and are not intended to limit the embodiments of this application.

[0055] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing embodiments of this application only and is not intended to limit this application.

[0056] In the following description, references are made to “some embodiments,” which describe a subset of all possible embodiments. However, it is understood that “some embodiments” may be the same subset or different subsets of all possible embodiments and may be combined with each other without conflict.

[0057] It should also be noted that the terms "first, second, and third" used in the embodiments of this application are only used to distinguish similar objects and do not represent a specific order of objects. It is understood that "first, second, and third" can be interchanged in a specific order or sequence where permitted, so that the embodiments of this application described herein can be implemented in an order other than that illustrated or described herein.

[0058] Furthermore, the reference to "embodiment" herein means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0059] The following is a description of the relevant technologies used in this application.

[0060] New energy batteries are being used more and more widely in daily life and industry. For example, new energy vehicles equipped with batteries are already widely used. In addition, batteries are being used more and more in the field of energy storage.

[0061] Currently, new energy batteries are being used more and more widely in daily life and industry. They are not only used in energy storage systems for hydropower, thermal power, wind power, and solar power plants, but also extensively in electric vehicles such as electric bicycles, electric motorcycles, and electric cars, as well as in aerospace and other fields. With the continuous expansion of the application areas of power batteries, the market demand is also constantly increasing.

[0062] In this application embodiment, the battery can be a single battery cell or a battery pack composed of multiple battery cells. A single battery cell refers to a basic unit capable of converting chemical energy into electrical energy, and can be used to manufacture battery modules or battery packs to supply power to electrical devices. A single battery cell can be a rechargeable battery, which is a battery cell that can be recharged after discharge to activate its active materials and continue to be used. A single battery cell can be a lithium-ion battery, sodium-ion battery, sodium-lithium-ion battery, lithium metal battery, sodium metal battery, lithium-sulfur battery, magnesium-ion battery, nickel-metal hydride battery, nickel-cadmium battery, lead-acid battery, etc., and this disclosure embodiment is not limited to this.

[0063] In this embodiment, the battery may also be a single physical module comprising one or more battery cells to provide higher voltage and capacity. When there are multiple battery cells, the multiple battery cells are connected in series, parallel, or mixed via a busbar.

[0064] Currently, the sampling accuracy promised by various AFE chip suppliers varies greatly. Moreover, it is impossible to guarantee that the sampling accuracy of each AFE chip is completely consistent. Even AFE chips produced by the same supplier have individual differences in sampling accuracy, which makes it impossible to guarantee the sampling accuracy of AFE chips.

[0065] If the cell voltage sampled by the AFE chip deviates significantly from the actual sampled voltage, it may cause over-balancing of the battery. The resulting cell voltage after balancing will not match the actual sampled voltage, affecting subsequent battery balancing processes and charging / discharging strategies. This, in turn, severely impacts battery life, safety, performance, and the user experience. Therefore, improving the sampling accuracy of the AFE chip to more accurately measure battery voltage is a pressing issue that needs to be addressed.

[0066] Based on this, embodiments of this application provide a calibration method, a battery management system, a battery device, and an electrical device. The calibration method first determines the offset of the first reference source based on the actual temperature and the first sampling voltage of the first reference source, and determines the offset of the second reference source based on the actual temperature and the second sampling voltage of the second reference source. This considers the impact of temperature changes on sampling accuracy, improving the accuracy and reliability of determining whether the reference source is offset. Second, since the voltages of both the first and second reference sources are based on a third reference source, the offset reference source is determined by comprehensively considering the offsets of both the first and second reference sources. This method can accurately identify the offset reference source. Finally, the gain error is determined based on the ratio of the average voltage to the voltage reference point, and the first or third sampling voltage is compensated based on the gain error. Because the offset of the second reference source is introduced as a reference for verification, the offset reference source can be accurately identified, further improving the accuracy of voltage sampling, enhancing the accuracy of subsequent sampling, improving battery safety and performance, and ultimately extending battery life.

[0067] The present application will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0068] In one embodiment of this application, Figure 1 A flowchart illustrating a calibration method provided in this application embodiment. Figure 1 .like Figure 1 As shown, the method may include:

[0069] S101, based on the actual temperature and the first sampling voltage of the first reference source, determine the offset of the first reference source; and based on the actual temperature and the second sampling voltage of the second reference source, determine the offset of the second reference source.

[0070] The first and second sampling voltages are both collected based on the third sampling voltage of the third reference source; the temperature range corresponds one-to-one with the voltage range.

[0071] In this embodiment, the actual temperature of the AFE chip corresponds to the first sampling voltage, the second sampling voltage, and the third sampling voltage. A correspondence is established between the temperature range of the actual temperature of the AFE chip and the voltage range of the first sampling voltage, the second sampling voltage, and the third sampling voltage, thereby reducing control complexity.

[0072] In this embodiment, the average temperature of the AFE chip collected within the same time period corresponds to the average voltage sampled by the first reference source, the average voltage sampled by the second reference source, and the average voltage sampled by the third reference source. By establishing a correspondence between the temperature range of the average temperature of the AFE chip and the voltage range of the average voltage sampled by the first reference source, the second reference source, and the third reference source, the control complexity is reduced.

[0073] The correspondence between the actual temperature range and the voltage range from the first sampling voltage to the third sampling voltage is the same as the correspondence between the average temperature range of the AFE chip and the average voltage of each reference source. The specific correspondence is referred to steps S301 to S401 in the following embodiments.

[0074] In the embodiments of this application and the following embodiments, the first reference source is labeled REF_CAP. Figure 2 The diagram shows the ADC (or VC path) section of the internal cell voltage sampling channel of the AFE chip, used for real-time monitoring of the cell voltage value. Here, VCn and VCn+1 are voltage signals from different cells. These signals are converted from high voltage to low voltage by a first voltage converter 201, such as an HVLS, and then input to a first filter 202, such as a 100kHz common-mode (CM) filter, to suppress high-frequency common-mode noise. Further, a first analog-to-digital converter 203, such as a Sigma Delta analog-to-digital converter (ADC), compares the signal output from the first filter 202 with the first sampled voltage of a first reference source, and then, based on a second filter 204, such as a third-order filter... After downsampling and noise suppression, the first voltage sampling signal is output. This first voltage sampling signal is the voltage sampling signal obtained by the AFE from sampling the cell voltage. In other words, the first voltage sampling signal output by the VC path is obtained based on the first sampling voltage of the first reference source REF_CAP. The first sampling voltage of the first reference source directly affects the output result of the first voltage sampling signal. If the first reference source is offset, it will cause errors in the first voltage sampling signal.

[0075] In the embodiments of this application and the following embodiments, the second reference source can be labeled as BG1 / BG2. The second reference source includes two separate spare reference sources, BG1 and BG2. These two reference sources are relatively stable and can be used as reference sources.

[0076] In the embodiments of this application and the following embodiments, the third reference source is labeled TSREF. Figure 3 The diagram shows the ADC (or CB path) section of the cell voltage equalization sampling channel inside the AFE chip. This is used to verify voltage sample values ​​in unbalanced mode, providing control basis for the equalization circuit. CBn, CBn+1, ..., CBn+6 represent the voltage signals of different cells. These different cell voltages pass through corresponding first controllers 205, such as high-voltage multiplexers (HV MUX). The HV MUX uses an internal switching matrix to select multiple high-voltage signals, which are then input to the first filter 202. The first analog-to-digital converter 203 compares the filtered signal with the third sampled voltage of the third reference source, and further filters it using the second filter 204, outputting a second voltage sampling signal. This second voltage sampling signal is the voltage sampling signal used by the AFE for equalization sampling. The second voltage sampling signal can be the voltage difference between different cells. In other words, the second voltage sampling signal output by the CB path is obtained based on the third sampling voltage of the third reference source TSREF. The third sampling voltage of the third reference source directly affects the output result of the second voltage sampling signal. If the third reference source is offset, it will cause errors in the second voltage sampling signal.

[0077] In the embodiments of this application, such as Figure 4 As shown, GPIO2, GPIO3, ..., GPIO12 are temperature signals of different battery cells. The second controller 206 can be a low voltage multiplexer (LV MUX) to select multiple temperature signals. Further, the selected temperature signals are input to the second voltage converter 207, such as LVLS, and further input to the second analog-to-digital converter 208, such as SD ADC GP. After being filtered by the second filter 204, the corresponding temperature sampling signal of the battery cell is output.

[0078] It should be noted that, as Figure 4 As shown, the voltage of the first reference source REF_CAP and the voltage of the second reference source BG1 / BG2 are read from the output port of the second controller 206. That is, the first sampled voltage of the first reference source REF_CAP and the second sampled voltage of the second reference source BG1 / BG2 are obtained by reading from the corresponding ports based on the third sampled voltage of the third reference source.

[0079] In this embodiment, the AFE chip completes a data acquisition within a short time (generally on the microsecond level) at preset intervals, such as 100ms, based on... Figure 4The circuit structure of a portion of the AFE chip is shown. Each time, the voltages of the first and second reference sources are read from their respective ports, and the temperature of the AFE chip is acquired based on other ports. Specifically, at the current moment, a set of data is acquired sequentially, including: the first sampling voltage of the first reference source, the second sampling voltage of the second reference source, and the actual temperature of the AFE chip.

[0080] As mentioned above, the voltage sampling accuracy of the AFE chip is strongly correlated with the actual temperature and the quality of the reference source. The offset of the first reference source can be determined by judging whether the first sampling voltage of the first reference source meets the voltage change law of the first reference source at the actual temperature; and the offset of the second reference source can be determined by judging whether the second sampling voltage of the second reference source meets the voltage change law of the second reference source at the actual temperature.

[0081] S102, if the first reference source has an offset and the second reference source does not have an offset, the offset reference source is determined to be the first reference source; or, if both the first and second reference sources have offsets, the offset reference source is determined to be the third reference source.

[0082] It should be noted that the first and third reference sources are independent reference sources. Therefore, the probability of both reference sources exhibiting voltage offsets simultaneously is the voltage offset of the first reference source multiplied by the lower PPM value of the voltage offset of the third reference source, which approaches 0. In other words, the first and third reference sources will not exhibit voltage offsets simultaneously.

[0083] As mentioned earlier, the second reference source is relatively stable and can be used as a reference source. That is to say, for the second reference source, if the third reference source shifts, the second reference source will also shift; if the third reference source does not shift, the second reference source will not shift.

[0084] Moreover, the first sampling voltage of the first reference source and the second sampling voltage of the second reference source are both independently acquired based on the third sampling voltage of the third reference source. Therefore, by comprehensively comparing the offset of the first reference source and the offset of the second reference source, it can be determined whether the offset is caused by the first reference source or the third reference source.

[0085] It should be noted that the offset of the first reference source is equivalent to the offset of the first sampling voltage of the first reference source; the offset of the third reference source is equivalent to the offset of the third sampling voltage of the third reference source.

[0086] It should be noted that, as mentioned above, based on Figure 4The voltages output by the first and second reference sources are both based on the voltage output by the third reference source. Moreover, the probability of both the first and third reference sources experiencing offset faults simultaneously is extremely low, making the second reference source a relatively stable reference source.

[0087] Therefore, in this embodiment of the application, if the first reference source shows an offset, it indicates that the third reference source, which serves as the reference for the first reference source, or the first reference source has an offset fault. However, if the second reference source does not show an offset, it indicates that the third reference source, which serves as the reference for the second reference source, has not an offset fault, and the first reference source has an offset fault.

[0088] Alternatively, in this embodiment of the application, if the first reference source is offset, it indicates that either the first or third reference source is offset; at the same time, if the second reference source is offset, it indicates that either the second or third reference source is offset. Therefore, it can be determined that if both the first and second reference sources are faulty, it is the third reference source that is offset.

[0089] It should be noted that, based on the aforementioned embodiments, if it is determined that the first reference source has not shifted, the shift of the second reference source does not need to be further determined, and the next set of data can be collected at a preset interval. Alternatively, if the first reference source shifts, indicating that the first reference source has shifted, or the shift of the third reference source can be observed on the second reference source, the shift of the second reference source can be further determined, and the shift of the first reference source and the shift of the second reference source can be combined to determine whether the shifted reference source is the first reference source or the third reference source.

[0090] S103, acquire the voltage range corresponding to the average temperature and the average voltage of the first reference source, and determine the voltage reference point based on the voltage range corresponding to the average temperature, determine the gain error based on the ratio of the average voltage and the voltage reference point, and compensate the first sampling voltage or the third sampling voltage based on the gain error.

[0091] In this embodiment of the application, the average temperature can be the average temperature of the AFE chip collected by the battery cell in a recent period of time, and the average voltage of the first reference source can be the average voltage of the first reference source collected in a period of time.

[0092] Among them, the method of determining the gain error based on the voltage range corresponding to the average temperature and the average voltage can gradually bring the offset closer to the correct value through multiple compensations, avoiding overcompensation of the first voltage sampling signal or the third voltage sampling signal.

[0093] It should be noted that the possible operating temperature range of the AFE chip is divided into multiple temperature ranges. Based on experimentally collected data, under different temperature ranges, the first sampling voltage of the first reference source is in different voltage ranges without any shift between the first and third reference sources. For example, when the temperature of the AFE chip is within the temperature range of -20℃ to 0.01℃, the first sampling voltage of the first reference source should be between 3.9935V and 4.0070V. Within a voltage range of 6.75mV.

[0094] Specifically, after determining the average temperature of the AFE chip, the voltage range of the first sampling voltage of the first reference source corresponding to the temperature range of the AFE chip's average temperature is taken as the voltage range corresponding to the average temperature.

[0095] Furthermore, a voltage value can be determined as a voltage reference point within the voltage range corresponding to the average temperature. The voltage reference point is a reference point used to determine the error of the first sampling voltage or the third sampling voltage. It is the normal value of the first sampling voltage when the AFE chip is at the average temperature and the first and third reference sources are not offset.

[0096] The voltage reference point can be the middle value within the voltage range, or it can be the value at which the first reference source has the highest probability of appearing in the voltage range when the AFE chip is at its average temperature, or it can be any value within the voltage range, without any specific limitation.

[0097] In this embodiment, the gain error can be determined based on the ratio of the average voltage to the voltage reference point. The gain error is the ratio of the acquired average voltage to the voltage reference point during normal operation, and can be understood as an indicator of the magnitude of the deviation of the first sampled voltage acquired by the first reference source.

[0098] Alternatively, since the first sampled voltage of the first reference source is acquired based on the third sampled voltage of the third reference source, the first sampled voltage will also shift when the third reference source shifts. Therefore, the gain error can also be used as an indicator to reflect the magnitude of the shift in the third sampled voltage acquired by the third reference source.

[0099] It should be noted that the gain error can indicate the deviation of the first reference source. When the offset reference source is the first reference source, the first sampled voltage of the first reference source can be compensated based on the gain error using a first compensation method (including steps S601-S603) to calibrate the first sampled voltage to the sampled voltage under the condition of no offset. Alternatively, since the first sampled voltage of the first reference source is obtained from the third sampled voltage of the third reference source, the gain error can indicate the deviation of the third reference source. When the offset reference source is the third reference source, the third sampled voltage of the third reference source can be compensated based on the gain error using a second compensation method (including steps S701-S703) to calibrate the first sampled voltage to the sampled voltage under the condition of no offset. The calculation process for calibrating the first sampled voltage of the first reference source can differ from the calculation process for calibrating the first sampled voltage of the third reference source.

[0100] It should also be noted that calibrating the first sampling voltage of the first reference source or the third sampling voltage of the third reference source can refer to compensating for the deviation of the first sampling voltage of the first reference source or the third sampling voltage of the third reference source based on the gain error, so as to correct the deviation value of the first sampling voltage or the third sampling voltage and ensure the accuracy of the sampling results.

[0101] This application provides a calibration method. First, the offset of the first reference source is determined based on the actual temperature and the first sampling voltage of the first reference source, and the offset of the second reference source is determined based on the actual temperature and the second sampling voltage of the second reference source. This takes into account the impact of temperature changes on sampling accuracy, improving the accuracy and reliability of determining whether the reference source is offset. Second, since the voltages of the first and second reference sources are both collected from a third reference source, the offset reference source is determined by comprehensively considering the offsets of the first and second reference sources. This method can accurately identify the reference source that has offset. Finally, the gain error is determined based on the ratio of the average voltage to the voltage reference point, and the first or third sampling voltage is compensated based on the gain error. Since the offset of the second reference source is introduced as a reference for verification, the offset reference source can be accurately identified, which further improves the accuracy of voltage sampling, enhances the accuracy of subsequent sampling, improves battery safety and performance, and thus extends battery life.

[0102] In some embodiments, for step S101, such as Figure 5 As shown, determining the offset of the first reference source based on the actual temperature and the first sampling voltage of the first reference source can include:

[0103] S301, determine the first preset voltage range corresponding to the actual temperature.

[0104] It should be noted that the voltage output by the first reference source may be within different preset voltage ranges when the temperature of the AFE chip is different.

[0105] For example, based on experimentally collected data, when the temperature of the AFE chip is within the range of -40℃ to 19.99℃, the preset voltage range corresponding to the voltage output by the first reference source can be 3.9935V-4.0100V. 8.25mV);

[0106] Alternatively, when the AFE chip's temperature is within the range of -20℃ to 0.01℃, the preset voltage range corresponding to the voltage output by the first reference source can be 3.9935V-4.0070V. 6.75mV);

[0107] Alternatively, when the AFE chip's temperature is within the range of 0℃ to 24.99℃, the preset voltage range corresponding to the voltage output by the first reference source can be 3.9930V to 4.0065V. 6.75mV);

[0108] Alternatively, when the AFE chip's temperature is within the range of 25℃ to 64.99℃, the preset voltage range corresponding to the voltage output by the first reference source can be 3.9938V to 4.0072V. );

[0109] Alternatively, when the AFE chip's temperature is within the range of 65℃-125℃, the preset voltage range corresponding to the voltage output by the first reference source can be 3.9955V-4.0110V. ).

[0110] In this embodiment, the actual temperature range of the AFE chip at the current moment can be determined first, and then the preset voltage range of the first reference source corresponding to that temperature range can be determined, which is the first preset voltage range. For example, when the actual temperature is 20°C, the first preset voltage range can be determined to be 3.9930V-4.0065V. 6.75mV).

[0111] S302, determine whether the first sampled voltage is within the first preset voltage range.

[0112] If yes, proceed to step S303; otherwise, proceed to step S304.

[0113] In this embodiment of the application, after determining the first preset voltage range, the first sampling voltage collected together with the actual temperature can be further compared with the upper and lower limits of the corresponding first preset voltage range to determine whether the first sampling voltage is within the first preset voltage range.

[0114] S303, when the first sampling voltage is within the first preset voltage range, determine that the offset of the first reference source is non-existent.

[0115] In this embodiment, if the first sampled voltage is between the upper and lower limits of the first preset voltage range, it is determined that the first sampled voltage is within the first preset voltage range. In this case, the first reference source has no offset, or the error is too small to be detected, or the error is within the limit range.

[0116] S304, if the first sampling voltage is not within the first preset voltage range, determine that the offset of the first reference source exists.

[0117] In this embodiment, if the first sampled voltage is not between the upper and lower limits of the first preset voltage range, it is determined that the first sampled voltage is not within the first preset voltage range. In this case, the first reference source is offset.

[0118] This application provides a calibration method that determines a first preset voltage range based on the actual temperature, and determines whether a first reference source has an offset by judging whether a first sampled voltage is within the first preset voltage range. Thus, the influence of temperature on the voltage of the first reference source is considered, thereby more accurately determining whether the first reference source has an offset, which helps to improve the accuracy of voltage sampling.

[0119] In some embodiments, for step S101, such as Figure 6 As shown, determining the offset of the second reference source based on the actual temperature and the second sampling voltage of the second reference source can include:

[0120] S401, determine the second preset voltage range corresponding to the actual temperature.

[0121] It should be noted that the voltage output by the second reference source may be within different preset voltage ranges when the temperature of the AFE chip is different.

[0122] For example, based on the experimentally collected data, when the temperature of the AFE chip is in the range of -40℃ to 19.99℃, the preset voltage range corresponding to the voltage output by the second reference source can be 1.2260V-1.2300V.

[0123] Alternatively, when the temperature of the AFE chip is within the temperature range of -20℃ to 0.01℃, the preset voltage range corresponding to the voltage output by the second reference source can be 1.2275V-1.2305V;

[0124] Alternatively, when the temperature of the AFE chip is within the temperature range of 0℃-24.99℃, the preset voltage range corresponding to the voltage output by the second reference source can be 1.2280V-1.2310V;

[0125] Alternatively, when the temperature of the AFE chip is within the temperature range of 25℃-64.99℃, the preset voltage range corresponding to the voltage output by the second reference source can be 1.2285V-1.2315V;

[0126] Alternatively, when the temperature of the AFE chip is within the temperature range of 65℃-125℃, the preset voltage range corresponding to the voltage output of the second reference source can be 1.2286V-1.2320V.

[0127] In this embodiment, the actual temperature range of the AFE chip at the current moment can be determined first, and then the preset voltage range of the second reference source corresponding to that temperature range can be determined, which is the second preset voltage range. For example, when the actual temperature is 40°C, the second preset voltage range can be determined to be 1.2285V-1.2315V.

[0128] S402, determine whether the second sampled voltage is within the second preset voltage range.

[0129] If yes, proceed to step S403; otherwise, proceed to step S404.

[0130] In this embodiment of the application, after determining the second preset voltage range, the second sampling voltage collected together with the actual temperature can be further compared with the upper and lower limits of the corresponding second preset voltage range to determine whether the second sampling voltage is within the second preset voltage range.

[0131] S403, when the second sampling voltage is within the second preset voltage range, determine that the offset of the second reference source is non-existent.

[0132] In this embodiment, if the second sampling voltage is between the upper and lower limits of the second preset voltage range, the first sampling voltage is determined to be within the second preset voltage range. In this case, the second reference source has no offset, or the error is too small to be detected, or the error is within the limit range.

[0133] S404, if the second sampling voltage is not within the second preset voltage range, determine that the offset of the second reference source exists.

[0134] In this embodiment, if the second sampling voltage is not between the upper and lower limits of the second preset voltage range, it is determined that the second sampling voltage is not within the second preset voltage range. In this case, the second reference source is offset.

[0135] This application provides a calibration method that determines a second preset voltage range based on the actual temperature, and determines whether a second reference source has an offset by judging whether the second sampled voltage is within the second preset voltage range. Thus, the influence of temperature on the voltage of the second reference source is considered, thereby more accurately determining whether the second reference source has an offset, which helps to improve the accuracy of voltage sampling.

[0136] In some embodiments, such as Figure 7 As shown, for S103, obtaining the voltage range corresponding to the average temperature and the average voltage of the first reference source, and determining the voltage reference point based on the voltage range corresponding to the average temperature, may include:

[0137] S501 determines the average voltage based on the first sampled voltage and multiple historical voltages.

[0138] Among them, multiple historical voltages are voltages collected by the first reference source at multiple times before the current time.

[0139] As mentioned above, after the AFE chip is powered on, a set of data is collected at the corresponding acquisition time every preset time interval, such as 100ms. This includes the voltage of the first reference source, the voltage of the second reference source, and the temperature of the AFE chip. Each data acquisition takes microseconds.

[0140] In this embodiment, the set of data collected at the current moment includes: the first sampling voltage of the first reference source, the second sampling voltage of the second reference source, and the actual temperature. The current moment can be any data collection moment after the AFE chip is powered on.

[0141] For example, the number of historical voltages can be nine. By averaging the first sampled voltage collected at the current moment and the voltages of the first reference source collected at the nine adjacent sampling moments before the current moment, the average voltage of the first reference source at the most recent 10 sampling moments can be determined.

[0142] It should be noted that after each set of data is collected, it is determined whether the first reference source has shifted based on the first sampling voltage of the first reference source and the corresponding actual temperature, and it is determined whether the second reference source has shifted based on the second sampling voltage of the second reference source and the corresponding actual temperature. If it is determined that the first or third reference source has shifted based on the aforementioned embodiments, the method of this application embodiment can be used to determine the gain error based on data collected near the time of shift and historical data collected, and to compensate the shifted reference source based on the gain error.

[0143] In this embodiment, the number of historical voltages can be set to a preset number according to actual needs. For example, in the above example, the preset number is 9. It should be noted that if the number of multiple historical voltages is less than the preset number, the average voltage can be calculated based on all historical voltages. For example, if at the 7th acquisition time after the AFE chip is powered on, and it is determined based on the aforementioned embodiment that the voltage of the first reference source has shifted, then the average voltage of the first reference source can be determined by averaging the first sampled voltage acquired at the current time (7th acquisition time) and 6 historical voltages to suppress noise interference.

[0144] S502 determines the average temperature based on the actual temperature and multiple historical temperatures.

[0145] Among them, multiple historical temperatures are temperatures collected at various times prior to the current moment.

[0146] As mentioned above, after the AFE chip is powered on, data including the temperature of the AFE chip is collected at preset intervals, such as 100ms.

[0147] In this embodiment of the application, the average temperature of the AFE chip can be determined by averaging the actual temperature of the AFE chip collected at the current time and the historical temperatures of the AFE chip collected at multiple adjacent times before the current time.

[0148] For example, the number of historical temperatures can be up to nine. By averaging the current actual temperature with the nine historical temperatures, the average temperature of the AFE chip over the last ten acquisition times can be determined.

[0149] It should also be noted that the number of historical temperatures can be set to a preset number according to actual needs. For example, in the example above, the preset number is 9. It should also be noted that if the number of multiple historical temperatures is less than the preset number, an average temperature can be calculated based on all historical temperatures to suppress noise interference.

[0150] S503 determines the corresponding voltage range based on the temperature range of the average temperature.

[0151] As mentioned above, the possible operating temperature range of the AFE chip is divided into multiple temperature ranges. Based on the experimental data, under different temperature ranges, the first sampling voltage of the first reference source is in different voltage ranges without any offset between the first and third reference sources.

[0152] S504 calculates the average of the upper and lower limits of the voltage range corresponding to the average temperature to determine the voltage reference point.

[0153] Referring to the aforementioned embodiments, the operating temperature range of the AFE chip is divided into multiple temperature ranges, such as: temperature range -40℃ to 19.99℃; temperature range -20℃ to 0.01℃; temperature range 0℃ to 24.99℃; temperature range 25℃ to 64.99℃; and temperature range 65℃ to 125℃.

[0154] Further, determining the average temperature within the aforementioned temperature range, and based on the example of step S301 above, obtaining the voltage range corresponding to that temperature range. For example, when the average temperature is 5°C, the corresponding temperature range can be determined to be 0°C-24.99°C, and the voltage range corresponding to the average temperature is 3.9935V-4.0070V. 6.75mV), the upper limit of the corresponding voltage range is 4.0070V. 6.75mV corresponds to a lower limit of the voltage range of 3.9935V. 6.75mV.

[0155] In this embodiment of the application, the upper limit of the voltage range corresponding to the average voltage and the lower limit of the voltage range corresponding to the average temperature are obtained, and the gain error is calculated and determined based on formula (1). :

[0156] (1)

[0157] in, The average voltage. This represents the upper limit of the voltage range corresponding to the temperature range where the average temperature is located. This represents the lower limit of the voltage range corresponding to the temperature range where the average temperature is located, based on... This means averaging the upper and lower limits of the voltage range corresponding to the average temperature to determine the voltage reference point.

[0158] It should be noted that the voltage within the voltage range follows a normal distribution, meaning that the midpoint of the normal distribution... It has the highest probability of appearing within the voltage range and can be used as a voltage reference point.

[0159] As mentioned above, the gain error can be an indicator of the magnitude of the deviation of the first or third sampled voltage, and can be determined based on the ratio of the average voltage of the first reference source to the voltage reference point. In the embodiments of this application, the gain error can be determined based on formula (1), and the gain error is determined based on the difference between the ratio of the average voltage of the first reference source to the voltage reference point and a first preset value. The first preset value can be 1, so that the absolute value of the gain error is between 0 and 1, which more intuitively indicates the proportion of the deviation of the first or third sampled voltage from the sampled voltage during normal operation.

[0160] This application provides a calibration method that determines an average voltage based on a first sampled voltage and multiple historical voltages, and an average temperature based on the actual temperature and multiple historical temperatures. Finally, the upper and lower limits of the voltage range corresponding to the average temperature are averaged to determine a voltage reference point, further determining the gain error. This method enables the determination of the gain error based on multiple historical data, improving the accuracy and reliability of the determined gain error, avoiding overcompensation, quickly restoring the reference source offset, and improving sampling efficiency.

[0161] It should be noted that, depending on the offset reference source, different methods can be used to determine the actual voltage value of the corresponding offset reference source based on the gain error.

[0162] In some embodiments, such as Figure 8 As shown, when the offset reference source is determined to be the first reference source, step S103, which involves calibrating the first or third sampled voltage of the offset reference source based on the gain error, may include:

[0163] S601 determines the compensation coefficient based on the gain error.

[0164] In this embodiment, the compensation coefficient can be the ratio of the average voltage of the first reference source to the sampling voltage (voltage reference point) during normal operation. When the gain error is determined based on formula (1), the compensation coefficient can be based on the sum of the gain error and a first preset value, where the first preset value can be 1, based on formula (1). express.

[0165] Alternatively, in some embodiments, where the gain error is determined based on the ratio of the average voltage of the first reference source to the voltage reference point, the compensation factor may be the same as the gain error.

[0166] S602, determine the first actual voltage based on the product of the first sampled voltage and the compensation coefficient.

[0167] In this embodiment of the application, the first actual voltage It can be calculated based on formula (2):

[0168] (2)

[0169] in, The first sampled voltage obtained by sampling the first reference source can be understood as the voltage reading before compensation of the first reference source. This represents the gain error.

[0170] It should be noted that if the average voltage is lower than the voltage during normal operation, but the actual voltage value does not change, it indicates an error, resulting in the obtained first sampled voltage being too high; conversely, if the average voltage is higher than the voltage during normal operation, it indicates an error, resulting in the obtained first sampled voltage being too low.

[0171] Furthermore, the first sampled voltage is multiplied by the ratio of the average voltage of the first reference source to the voltage reference point. When the average voltage is smaller than the voltage during normal operation, the compensation coefficient is less than 1, and the larger first sampled voltage is compensated to decrease it; or, when the average voltage is larger than the voltage during normal operation, the compensation coefficient is greater than 1, and the smaller first sampled voltage is compensated to increase it.

[0172] S603, compensates the first sampled voltage of the first reference source based on the first actual voltage.

[0173] In this embodiment, the first sampling voltage of the first reference source is replaced with the first actual voltage determined based on the above steps. The first actual voltage is used as the true voltage of the first reference source after compensation, thereby completing the compensation of the first sampling voltage of the first reference source and calibrating the first sampling voltage to the voltage when it is working normally.

[0174] It should be noted that after calibrating the first sampling voltage of the first reference source, the first reference source may still have an offset. In this case, the gain error at the new current moment can be determined based on the aforementioned steps S501-S503 and steps S601-S602, the first actual voltage can be further determined, and the first reference source can be calibrated based on the first actual voltage.

[0175] This application provides a calibration method in which, when the offset reference source is a first reference source, a first actual voltage is determined based on a first sampling voltage and a gain error, and the first reference source is calibrated based on the first actual voltage. This allows for customized design of compensation logic, more accurate offset compensation, and thus improved sampling efficiency.

[0176] In some embodiments, such as Figure 9As shown, when the offset reference source is determined to be the third reference source, step S103, which involves calibrating the first or third sampled voltage of the offset reference source based on the gain error, may include:

[0177] S701 determines the compensation coefficient based on the gain error.

[0178] In this embodiment, the compensation coefficient can be the ratio of the first sampling voltage to the sampling voltage during normal operation. When the gain error is determined based on formula (1), the compensation coefficient can be based on the sum of the gain error and a first preset value, where the first preset value can be 1. express.

[0179] Alternatively, in some embodiments, where the gain error is determined based on the ratio of the average voltage of the first reference source to the voltage reference point, the compensation factor may be the same as the gain error.

[0180] S702 determines the second actual voltage based on the ratio of the third sampled voltage to the compensation coefficient.

[0181] In this embodiment of the application, the second actual voltage It can be determined based on formula (3):

[0182] (3)

[0183] in, The third sampled voltage, obtained by sampling the third reference source, can be understood as the voltage reading before compensation of the third reference source. This represents the gain error.

[0184] As mentioned above, the first sampling voltage is acquired based on the third sampling voltage. Therefore, the gain error determined based on the first sampling voltage can be used to reflect the offset amplitude of the third sampling voltage, and the offset amplitude is related to the correspondence between the first sampling voltage and the third sampling voltage.

[0185] Based on the summary of multiple test data, it can be determined that there is a similar inverse quantitative relationship between the first sampling voltage and the third sampling voltage. After experimental verification, the second actual voltage can be calculated and determined by formula (3) based on the ratio of the third sampling voltage and the compensation coefficient.

[0186] S703 compensates for the third sampling voltage of the third reference source based on the second actual voltage.

[0187] In this embodiment, the third sampling voltage of the third reference source is replaced with the second actual voltage determined based on the above steps, and the second actual voltage is used as the true voltage of the compensated third reference source to complete the calibration of the third sampling voltage of the third reference source.

[0188] It should be noted that after calibrating the third sampling voltage of the third reference source, the third reference source may still have an offset. In this case, the gain error at the new current moment can be determined based on the aforementioned steps S501-S503 and steps S701-S702, the second actual voltage can be further determined, and the third reference source can be calibrated based on the true value of the second voltage.

[0189] This application provides a calibration method in which, when the offset reference source is a third reference source, a second actual voltage is determined based on the third sampling voltage and the gain error, and the third reference source is calibrated based on the second actual voltage. This allows for customized design of compensation logic, more accurately offsetting the offset and thus improving sampling efficiency.

[0190] The calibration method provided in the embodiments of this application will be described in detail below with reference to specific application scenarios.

[0191] Currently, the AFE chip experiences a significant temperature rise during the equalization process, resulting in inherent errors in its sampling accuracy. Furthermore, since the sampling accuracy of each AFE cannot be guaranteed to be completely consistent, the sampling error caused by individual differences and temperature rise will be amplified, potentially leading to over-equalization. The cell voltage collected after equalization may not match the true value, thus affecting the subsequent charging and discharging strategies of the cells.

[0192] Therefore, it is necessary to ensure the sampling accuracy of the AFE chip at different temperatures. The sampling accuracy of the AFE chip largely depends on the stability of its internal cell voltage (REF_CAP) / equalization voltage sampling ADC reference source (TSREF), but the accuracy of the ADC reference source itself fluctuates with temperature. In this embodiment, the sampling accuracy of the cell is ensured by exploring the variation pattern of the AFE chip's cell voltage / equalization voltage sampling ADC reference source at different temperatures.

[0193] In this embodiment of the application, the calibration method includes: acquiring the parameter changes of the AFE chip cell voltage reference source (first reference source) / equalization voltage sampling ADC reference source (third reference source) over the entire temperature range; further determining whether to perform compensation calibration on the cell voltage reference source / equalization voltage reference source collected at the current temperature based on its parameters and in combination with the parameters of the spare reference source inside the AFE chip as a function of temperature; and finally obtaining the accurate cell voltage value after compensation.

[0194] In this embodiment of the application, based on the calibration method provided in this embodiment, the cell voltage / equalization channel sampling value can be obtained more accurately under different temperature conditions: the current temperature of the chip is collected multiple times and the average value is calculated, and the value of the reference source at the current temperature is read multiple times and the average value is calculated. Finally, it is determined whether the cell voltage / equalization voltage sampling at the current temperature needs to be compensated.

[0195] like Figure 10 As shown, the calibration method provided in this application includes:

[0196] S801: Power on and read the first sampled voltage of the first reference source.

[0197] First, the temperature of the AFE chip is read 10 times and the average value is taken (the sampling period of the current AFE chip temperature in the BMS software is 100ms. If the sampled values ​​of cell voltage REF_CAP / equalization voltage TSREF read by the ADC have already shifted before the 10 AFE chip samples are completed at the beginning of power-on, then the compensation will not be performed after the 10 temperature samples are completed, but will be judged directly based on the current and previous AFE chip temperatures) to suppress noise interference.

[0198] Secondly, the value of the first reference source (which can be called REF_CAP ADC or REF_CAP) of the AFE chip is read 10 times and the average value is taken (the sampling period of the current REF_CAP ADC in the BMS software is 100ms. If the cell voltage / equalization voltage sample value read by the ADC has already been offset before the 10 reference source samples are completed when the power is first turned on, the compensation will not be performed after the 10 reference source samples are completed. The judgment will be made directly based on the current sampled REF_CAP ADC) to suppress noise interference.

[0199] Finally, it is determined whether the first sampled voltage acquired by the first reference source at the current moment exceeds the threshold range of the actual temperature at the current moment (the chip REF_CAP ADC read value is read from the third reference source (which can be called TSREF); since TSREF and REF_CAP are independent reference sources, the failure rate of the two reference sources is the low PPM of TSREF * the low PPM of REF_CAP. Since the PPM is almost 0, TSREF and REF_CAP will not fail at the same time; therefore, it can be preliminarily determined from the REF_CAP ADC read value whether there is an offset between the two reference sources REF_CAP / TSREF).

[0200] The relationship between the temperature range of the AFE chip and the preset voltage range of the first reference source is as follows:

[0201] Define temperature range #1: -40℃ to 19.99℃, and the corresponding preset voltage range of the first reference source is: 3.9935V <= REFCAP ADC <= 4.0100V (+ / - 8.25mV).

[0202] Define temperature range #2: -20℃ to 0.01℃, and the corresponding preset voltage range of the first reference source is: 3.9935V <= REFCAP ADC <= 4.0070V (+ / - 6.75mV).

[0203] Define temperature range #3: 0℃-24.99℃, and the corresponding preset voltage range of the first reference source is: 3.9930V<=REFCAP ADC<=4.0065V(+ / -6.75mV).

[0204] Define temperature range #4: 25℃-64.99℃, and the corresponding preset voltage range of the first reference source is: 3.9938V<=REFCAP ADC<=4.0072V (+ / -6.75mV).

[0205] Define temperature range #5: 65℃-125℃, and the corresponding preset voltage range of the first reference source is: 3.9955V<=REFCAP ADC<=4.0110V (+ / -7.75mV).

[0206] If the REFCAP ADC read value is between the upper and lower limits defined for the preset voltage range corresponding to each of the above temperature ranges, then REFCAP and TSREF are compliant with specifications, or the error is too small to be detected on the second reference source (which may be referred to as BG1 / 2). The compensation algorithm should abort. Any error within the limits will not be compensated by the algorithm.

[0207] If the REFCAP ADC exceeds the upper or lower limit defined for the preset voltage range corresponding to each of the above temperature ranges, then REFCAP or TSREF is not compliant with specifications and the error is large enough to be detected on BG1 / 2. In this case, step S803 should be executed.

[0208] If the first sampling voltage is within the first preset voltage range, proceed to step S802:

[0209] S802: No action taken.

[0210] If the first sampling voltage is not within the first preset voltage range, proceed to step S803:

[0211] S803: Read the second sampled voltage of the second reference source.

[0212] First, the second reference source (BG1 / BG2) of the AFE chip is read 10 times and the average value is taken to suppress noise interference. BG1 and BG2 are two other independent voltage references for the AVDD, DVDD, LDOIN, and VC OVUV protectors inside the AFE chip. They are manufactured using different processes than the REF_CAP and TSREF reference sources, and their reference sources are always kept within the specification range. In addition, BG1 and BG2 are read from TSREF as the reference source. Therefore, when the REF_CAP ADC read value exceeds the threshold, BG1 and BG2 can be read as references to determine the offset between the REF_CAP and TSREF reference sources.

[0213] Then, the TSREF is checked for offset by reading BG1 and BG2.

[0214] Define temperature range #1: -40℃ to 19.99℃. The corresponding preset voltage range of the second reference source is: 1.2260V <= BG1 / 2 <= 1.2300V. Then TSREF does not shift.

[0215] Define temperature range #2: -20℃ to 0.01℃. The corresponding preset voltage range of the second reference source is: 1.2275V <= BG1 / 2 <= 1.2305V. Then TSREF has not shifted.

[0216] Define temperature range #3: 0℃-24.99℃, and the corresponding preset voltage range of the second reference source is: 1.2280V<=BG1 / 2<=1.2310V, then TSREF has not shifted;

[0217] Define temperature range #4: 25℃-64.99℃. The corresponding preset voltage range of the second reference source is: 1.2285V<=BG1 / 2<=1.2315V. Then TSREF has not shifted.

[0218] Define temperature range #5: 65℃-125℃. The corresponding preset voltage range of the second reference source is: 1.2286V<=BG1 / 2<=1.2320V. Then TSREF does not shift.

[0219] If BG1 and BG2 are between the upper and lower limits defined for each of the above Bins, then TSREF conforms to the specification, and REFCAP is a non-compliant baseline source. The user should proceed to step S804.

[0220] If BG1 or BG2 exceeds the upper or lower limit defined for each of the above Bins, then REFCAP is compliant with the specification, and TSREF is a non-compliant offset reference source. In this case, step S805 should be executed.

[0221] Furthermore, based on the average temperature corresponding to the current temperature 10 of the AFE chip obtained above, and the average voltage corresponding to the REF_CAP ADC value 10 of the AFE chip, the gain error is calculated and determined based on formula (1).

[0222] If the second sampling voltage is within the second preset voltage range, proceed to step S804:

[0223] S804: Determine that there is an offset in the first reference source, and compensate for the cell voltage sampling (first sampling voltage).

[0224] If BG1 / 2 is not out of range, it is determined to be REF_CAP offset, and then formula (2) is applied for correction.

[0225] If the second sampling voltage is not within the second preset voltage range, proceed to step S805:

[0226] S805: Determines that there is an offset in the third reference source and compensates for it by equalizing the voltage sampling (third sampling voltage).

[0227] If BG1 / 2 is out of range, it is determined to be a TSREF offset, and then formula (3) is applied for correction.

[0228] Thus, based on the calibration method provided in the embodiments of this application, Figure 11 The values ​​represent the errors of the sampled voltages obtained at -40℃, 25℃, and 85℃, respectively. It can be seen that the error of the sampled voltages is smaller after adopting the calibration method of this application embodiment.

[0229] This application provides a calibration method that uses an internal spare reference source within the AFE chip to verify the cell voltage / equalization voltage sampling ADC reference source. This accurately determines the stability of the reference source, thus ensuring sampling accuracy. Furthermore, by subdividing the permissible variation range of the cell voltage / equalization voltage sampling ADC reference source under different temperature ranges, the method is more precise than the larger permissible variation under full temperature, which is also more conducive to sampling accuracy. Moreover, by taking the average value of chip temperature / cell voltage / equalization voltage after multiple samplings, sampling errors caused by sudden temperature jumps can be avoided, ensuring sampling accuracy.

[0230] In yet another embodiment of this application, Figure 12 This is a schematic diagram illustrating the composition of a battery management system according to an embodiment of this application. The battery management system 120 may include:

[0231] The sampling circuit 1201 is used to acquire the actual temperature, the first sampling voltage of the first reference source, and the second sampling voltage of the second reference source; the first sampling voltage and the second sampling voltage are both acquired based on the third sampling voltage of the third reference source; wherein the temperature range corresponds one-to-one with the voltage range.

[0232] The controller 1202 is configured to determine the offset reference source as the first reference source when the first reference source has an offset and the second reference source does not have an offset; or, when both the first and second reference sources have offsets, determine the offset reference source as the third reference source; acquire the voltage range corresponding to the average temperature and the average voltage of the first reference source, and determine a voltage reference point based on the voltage range corresponding to the average temperature, determine the gain error based on the ratio of the average voltage and the voltage reference point, and compensate the first sampled voltage or the third sampled voltage based on the gain error.

[0233] In some embodiments, the controller 1202 is further configured to determine a first preset voltage range corresponding to the actual temperature; if the first sampling voltage is not within the first preset voltage range, determine that the offset of the first reference source exists; or, if the first sampling voltage is within the first preset voltage range, determine that the offset of the first reference source does not exist.

[0234] In some embodiments, the controller 1202 is further configured to determine a second preset voltage range corresponding to the actual temperature; if the second sampling voltage is not within the second preset voltage range, determine that the offset of the second reference source exists; or, if the second sampling voltage is within the second preset voltage range, determine that the offset of the second reference source does not exist.

[0235] In some embodiments, the controller 1202 is further configured to determine the offset reference source as the first reference source when the first reference source has an offset and the second reference source does not have an offset; or, when both the first reference source and the second reference source have offsets, determine the offset reference source as the third reference source.

[0236] In some embodiments, the controller 1202 is further configured to: determine an average voltage based on a first sampled voltage and multiple historical voltages; determine an average temperature based on an actual temperature and multiple historical temperatures; wherein the multiple historical voltages are voltages collected by the first reference source at multiple times prior to the current time; determine a corresponding voltage range based on the temperature range in which the average temperature is located; wherein the multiple historical temperatures are temperatures collected at multiple times prior to the current time; and calculate the voltage reference point by averaging the upper and lower limits of the voltage range corresponding to the average temperature.

[0237] In some embodiments, the controller 1202 is further configured to determine a compensation coefficient based on the gain error; determine a first actual voltage based on the product of the first sampled voltage and the compensation coefficient; and compensate the first sampled voltage of the first reference source based on the first actual voltage.

[0238] In some embodiments, the controller 1202 is further configured to determine a compensation coefficient based on the gain error; determine a second actual voltage based on the ratio of the third sampled voltage to the compensation coefficient; and compensate the third sampled voltage of the third reference source based on the second actual voltage.

[0239] The Battery Management System (BMS) 120 in this application is used to perform at least one of the following functions for battery: state monitoring, state analysis, charge / discharge control, safety protection, thermal management, high-voltage power distribution, and information management. In addition, the Battery Management System 120 in this application can also implement the functions of a controller in an electrical device, such as a vehicle control unit (VCU) or a motor control unit (MCU), etc., and this application does not impose any limitations on this.

[0240] It should be noted that the battery management system 120 in this application may be partially or wholly integrated into the battery device, such as into the battery pack or energy storage box.

[0241] The battery management system 120 in this application can be partially or wholly integrated into an electrical device, such as in a vehicle or vehicle chassis.

[0242] The battery management system 120 in this application may be partially or wholly integrated into the charging device, such as into the charging device or the battery swapping device.

[0243] The battery management system 120 in this application can also be deployed as control software on a server. The server can be a standalone physical server, a server cluster or distributed system composed of multiple physical servers, or a cloud server that provides basic cloud computing services such as cloud services, cloud databases, cloud computing, cloud functions, cloud storage, network services, cloud communication, middleware services, domain name services, security services, CDN (Content Delivery Network), and big data and artificial intelligence platforms, such as vehicle networking cloud and APP backend.

[0244] In another embodiment of this application, a battery device is provided, such as... Figure 13 As shown, the battery device 130 includes a battery 1301 and the battery management system 120 in the aforementioned embodiments.

[0245] The battery management system 120 is used to control the charging process of the battery 1301 based on the calibration method in the foregoing embodiments.

[0246] In another embodiment of this application, an electrical appliance is provided, such as... Figure 14 As shown, the electrical device 140 includes the battery device 130 in the aforementioned embodiments.

[0247] In this embodiment, the electrical device 140 can be a battery-powered device that includes a battery device 130, which can periodically wake up the internal wake-up module. For example, the electrical device 140 can be a new energy vehicle, ship, aircraft, etc., or a power device such as an electric vehicle, hybrid vehicle, or electric motorcycle.

[0248] It should be understood that those skilled in the art will recognize that this application may take the form of a hardware embodiment, a software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application may take the form of a computer program product implemented on one or more computer-usable storage media (including, but not limited to, disk storage and optical storage) containing computer-usable program code.

[0249] It should also be understood that the phrase "an embodiment" or "one embodiment" throughout the specification means that a specific feature, structure, or characteristic related to the embodiment is included in at least one embodiment of this application. Therefore, "in one embodiment" or "one embodiment" appearing throughout the specification does not necessarily refer to the same embodiment. Furthermore, these specific features, structures, or characteristics can be combined in any suitable manner in one or more embodiments. It should be understood that in the various embodiments of this application, the sequence numbers of the above steps / processes do not imply a sequential order of execution; the execution order of each step / process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application. The sequence numbers of the above embodiments of this application are merely descriptive and do not represent the superiority or inferiority of the embodiments.

[0250] It should be noted that, in this application, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0251] In the several embodiments provided in this application, it should be understood that the disclosed systems, devices, and methods can be implemented in other ways. The device embodiments described above are merely illustrative. For example, the division of units is only a logical functional division, and in actual implementation, there may be other division methods, such as: multiple units or components may be combined, or integrated into another system, or some features may be ignored or not executed. In addition, the coupling, direct coupling, or communication connection between the various components shown or discussed may be through some interfaces, and the indirect coupling or communication connection between devices or units may be electrical, mechanical, or other forms.

[0252] The units described above as separate components may or may not be physically separate, and the components shown as units may or may not be physical units; they may be located in one place or distributed across multiple network units; some or all of the units may be selected to achieve the purpose of this embodiment according to actual needs. Furthermore, in the embodiments of this application, all functional units may be integrated into one processing unit, or each unit may be a separate unit, or two or more units may be integrated into one unit; the integrated unit may be implemented in hardware or in a combination of hardware and software functional units.

[0253] The above are merely preferred embodiments of this application and are not intended to limit the scope of protection of this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the scope of protection of this application.

Claims

1. A calibration method, characterized in that, The method includes: Based on the actual temperature and the first sampling voltage of the first reference source, the offset of the first reference source is determined; and based on the actual temperature and the second sampling voltage of the second reference source, the offset of the second reference source is determined; the first sampling voltage and the second sampling voltage are both collected based on the third sampling voltage of the third reference source; wherein, the temperature range corresponds one-to-one with the voltage range; If the first reference source has an offset and the second reference source does not have an offset, the offset reference source is determined to be the first reference source; or, if both the first reference source and the second reference source have offsets, the offset reference source is determined to be the third reference source. The voltage range corresponding to the average temperature and the average voltage of the first reference source are obtained, and a voltage reference point is determined based on the voltage range corresponding to the average temperature. The gain error is determined based on the ratio of the average voltage and the voltage reference point, and the first sampling voltage or the third sampling voltage is compensated based on the gain error.

2. The method according to claim 1, characterized in that, The determination of the offset of the first reference source based on the actual temperature and the first sampling voltage of the first reference source includes: Determine the first preset voltage range corresponding to the actual temperature; If the first sampling voltage is not within the first preset voltage range, the offset of the first reference source is determined to exist; or, if the first sampling voltage is within the first preset voltage range, the offset of the first reference source is determined to exist.

3. The method according to claim 1, characterized in that, The determination of the offset of the second reference source based on the actual temperature and the second sampling voltage of the second reference source includes: Determine the second preset voltage range corresponding to the actual temperature; If the second sampling voltage is not within the second preset voltage range, the offset of the second reference source is determined to exist; or, if the second sampling voltage is within the second preset voltage range, the offset of the second reference source is determined to exist.

4. The method according to claim 1, characterized in that, The steps of obtaining the voltage range corresponding to the average temperature and the average voltage of the first reference source, and determining the voltage reference point based on the voltage range corresponding to the average temperature, include: The average voltage is determined based on the first sampled voltage and multiple historical voltages; the multiple historical voltages are the voltages collected by the first reference source at multiple times before the current time. The average temperature is determined based on the actual temperature and multiple historical temperatures; the multiple historical temperatures are the temperatures collected at the multiple times prior to the current time. Based on the temperature range in which the average temperature falls, determine the corresponding voltage range; The voltage reference point is determined by averaging the upper and lower limits of the voltage range corresponding to the average temperature.

5. The method according to claim 1, characterized in that, When the offset reference source is determined to be the first reference source, the compensation of the first sampled voltage based on the gain error includes: Based on the gain error, determine the compensation coefficient; The first actual voltage is determined based on the product of the first sampled voltage and the compensation coefficient; The first sampling voltage of the first reference source is compensated based on the first actual voltage.

6. The method according to claim 1, characterized in that, When the offset reference source is determined to be the third reference source, the compensation of the third sampled voltage based on the gain error includes: Based on the gain error, determine the compensation coefficient; The second actual voltage is determined based on the ratio of the third sampled voltage to the compensation coefficient; The third sampling voltage of the third reference source is compensated based on the second actual voltage.

7. A battery management system, characterized in that, include: The sampling circuit is used to acquire the actual temperature, the first sampling voltage of the first reference source, and the second sampling voltage of the second reference source; the first sampling voltage and the second sampling voltage are both acquired based on the third sampling voltage of the third reference source; wherein the temperature range corresponds one-to-one with the voltage range. The controller is configured to determine the offset reference source as the first reference source when the first reference source has an offset and the second reference source does not have an offset; or, when both the first and second reference sources have offsets, determine the offset reference source as the third reference source; acquire the voltage range corresponding to the average temperature and the average voltage of the first reference source, and determine a voltage reference point based on the voltage range corresponding to the average temperature, determine a gain error based on the ratio of the average voltage to the voltage reference point, and compensate the first sampled voltage or the third sampled voltage based on the gain error.

8. A battery device, characterized in that, Includes a battery and a battery management system as described in claim 7.

9. An electrical appliance, characterized in that, Includes the battery device as described in claim 8.

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