Battery management system, battery management method, battery pack and power-consuming device

Abstract

The present application provides a battery management system, a battery management method, a battery pack and an electrical device, which belong to the field of battery technology. The battery management system includes: a detection circuit connected to a battery, configured to detect the current flowing through the battery, the detection circuit includes: a detection resistor; a voltage detector; a controller, configured to: calibrate at least one of the resistance value of the detection resistor and the voltage difference across the detection resistor to obtain at least one of the calibrated resistance value and the calibrated voltage difference, including at least one of the following: calibrate the resistance value of the detection resistor based on the ambient temperature of the battery; calibrate the voltage difference across the detection resistor; calibrate the current flowing through the battery based on at least one of the calibrated resistance value and the calibrated voltage difference to obtain the calibrated current; integrate the calibrated current in ampere-hours to obtain the remaining power of the battery. The battery management system can improve the detection accuracy of the remaining power of the battery.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and in particular to a battery management system, a battery management method, a battery pack and an electrical device. Background Art

[0002] Energy conservation and emission reduction are the key to the sustainable development of the automobile industry. Electric vehicles have become an important part of the sustainable development of the automobile industry due to their advantages in energy conservation and environmental protection. For electric vehicles, battery technology is an important factor in their development.

[0003] During the use of the battery, the remaining power needs to be detected. The accuracy of the remaining power detection of the battery is related to the safety, reliability and service life of the battery. If the remaining power of the battery cannot be accurately obtained, it will have a great impact on the performance of the battery. Summary of the invention

[0004] The present application aims to at least solve the technical problem of inaccurate detection of the remaining battery power in the background art. To this end, one purpose of the present application is to provide a battery management system to improve the detection accuracy of the remaining battery power.

[0005] The embodiment of the first aspect of the present application provides a battery management system, comprising: a detection circuit connected to a battery and configured to detect a current flowing through the battery, the detection circuit comprising: a detection resistor connected to the battery; a voltage detector configured to detect a voltage difference across the detection resistor, wherein the current flowing through the battery is determined according to a resistance value of the detection resistor and a voltage difference across the detection resistor, and includes a discharge current or a charge current of the battery; a controller configured to: calibrate at least one of a resistance value of the detection resistor and a voltage difference across the detection resistor to obtain at least one of a calibrated resistance value and a calibrated voltage difference, including at least one of the following items: based on the resistance of the battery; The method comprises: obtaining the resistance of the detection resistor at the ambient temperature; determining the resistance calibration coefficient corresponding to the ambient temperature based on the ambient temperature and a predetermined resistance calibration coefficient-temperature correspondence; obtaining the calibrated resistance according to the resistance of the detection resistor at the ambient temperature and the resistance calibration coefficient corresponding to the ambient temperature; calibrating the voltage difference across the detection resistor to obtain the calibrated voltage difference; calibrating the current flowing through the battery based on at least one of the calibrated resistance and the calibrated voltage difference to obtain the calibrated current; and integrating the calibrated current by ampere-hour to obtain the remaining power of the battery.

[0006] In the technical solution of the embodiment of the present application, the remaining power of the battery is obtained by integrating the current in ampere hours. By reducing the error of the detection resistor and / or reducing the error of the voltage difference across the detection resistor, the detection error of the current flowing through the battery is reduced, thereby reducing the accumulated error in the ampere-hour integration of the current and improving the detection accuracy of the remaining power. The detection error of the resistance can be reduced by calibrating the resistance of the detection resistor according to the ambient temperature. The voltage difference across the detection resistor can be calibrated to reduce the detection error of the voltage difference. Thereby, the detection accuracy of the current can be improved, and the detection accuracy of the remaining power can be further improved. Under different ambient temperatures, the resistance of the detection resistor is calibrated using different resistance calibration coefficients, which can reduce the detection error of the resistance at different temperatures and improve the detection accuracy.

[0007] In some embodiments, the resistance calibration coefficient-temperature correspondence is predetermined according to the following steps: obtaining a reference resistance value, which indicates the resistance value of the detection resistor at a first temperature; obtaining the resistance values ​​of the detection resistor at multiple temperatures; determining the resistance calibration coefficients corresponding to multiple temperatures respectively according to the resistance values ​​of the detection resistor at multiple temperatures and the reference resistance value; fitting the multiple temperatures and the resistance calibration coefficients corresponding to the multiple temperatures respectively to obtain the resistance calibration coefficient-temperature correspondence. The resistance values ​​and the reference resistance values ​​at multiple temperatures are obtained in advance, and the resistance calibration coefficient-temperature correspondence is further fitted, so that the resistance calibration coefficients corresponding to different ambient temperatures can be determined, and the resistance calibration at different temperatures can be calibrated.

[0008] In some embodiments, calibrating the voltage difference across the detection resistor to obtain the calibrated voltage difference includes at least one of the following: calibrating the voltage difference across the detection resistor according to a predetermined first voltage calibration coefficient to obtain the calibrated voltage difference; calibrating the voltage difference across the detection resistor based on the ambient temperature to obtain the calibrated voltage difference. Calibrating the voltage difference across the detection resistor according to the first voltage calibration coefficient and / or the ambient temperature can reduce the detection error of the voltage difference and improve the detection accuracy.

[0009] In some embodiments, the first voltage calibration coefficient is predetermined according to the following steps: applying multiple currents to the detection resistor at multiple current values, the multiple currents corresponding to the multiple current values; obtaining the current values ​​flowing through the detection resistor corresponding to the multiple currents; fitting the multiple current values ​​and the current values ​​flowing through the detection resistor corresponding to the multiple currents to obtain the fitting results; and determining the first voltage calibration coefficient according to the fitting results. By applying currents of different current values ​​to the detection resistor and determining the set value and the detection value of the current applied to the detection resistor, the voltage calibration process is converted into a current calibration process, so that the voltage calibration coefficient can be accurately determined when the voltage is small, thereby improving the detection accuracy of the voltage difference.

[0010] In some embodiments, according to a predetermined first voltage calibration coefficient, the voltage difference across the detection resistor is calibrated to obtain the calibrated voltage difference, including: determining the first voltage calibration coefficient corresponding to the ambient temperature based on the ambient temperature and the predetermined first voltage calibration coefficient-temperature correspondence relationship; according to the first voltage calibration coefficient corresponding to the ambient temperature, calibrating the voltage difference across the detection resistor to obtain the calibrated voltage difference. After obtaining the first voltage calibration coefficient, the first voltage calibration coefficient under different ambient temperatures is further determined to further improve the detection accuracy of the voltage difference.

[0011] In some embodiments, the first voltage calibration coefficient-temperature correspondence is predetermined according to the following steps: determining the first voltage calibration coefficients corresponding to a plurality of temperatures respectively; fitting the plurality of temperatures and the first voltage calibration coefficients corresponding to the plurality of temperatures respectively to obtain the first voltage calibration coefficient-temperature correspondence. By fitting the plurality of temperatures and the first voltage calibration coefficients corresponding to the plurality of temperatures respectively, the first voltage calibration coefficients corresponding to different ambient temperatures can be determined, thereby achieving calibration of the voltage difference at different temperatures.

[0012] In some embodiments, based on the ambient temperature, the voltage difference across the detection resistor is calibrated to obtain the calibrated voltage difference, including: obtaining the voltage difference across the detection resistor at the ambient temperature; determining the second voltage calibration coefficient corresponding to the ambient temperature based on the ambient temperature and a predetermined second voltage calibration coefficient-temperature correspondence; and obtaining the calibrated voltage difference according to the voltage difference across the detection resistor at the ambient temperature and the second voltage calibration coefficient corresponding to the ambient temperature. Using different second voltage calibration coefficients to calibrate the voltage difference across the detection resistor at different ambient temperatures can reduce the detection error of the voltage difference at different temperatures and improve the detection accuracy.

[0013] In some embodiments, the second voltage calibration coefficient-temperature correspondence is predetermined according to the following steps: obtaining a reference voltage difference, the reference voltage difference indicating the voltage difference between the two ends of the detection resistor at the second temperature; obtaining the voltage difference between the two ends of the detection resistor at multiple temperatures; determining the second voltage calibration coefficients corresponding to multiple temperatures respectively according to the voltage difference between the two ends of the detection resistor at multiple temperatures and the reference voltage difference; fitting multiple temperatures and the second voltage calibration coefficients corresponding to multiple temperatures respectively to obtain the second voltage calibration coefficient-temperature correspondence. The voltage difference and the reference voltage difference at multiple temperatures are obtained in advance, and the second voltage calibration coefficient-temperature correspondence is further fitted, so that the second voltage calibration coefficient corresponding to different ambient temperatures can be determined, and the voltage difference at different temperatures can be calibrated.

[0014] The embodiment of the second aspect of the present application provides a battery management method, including: calibrating at least one of the resistance of a detection resistor in a detection circuit and the voltage difference across the detection resistor to obtain at least one of the calibrated resistance and the calibrated voltage difference, including at least one of the following items: calibrating the resistance of the detection resistor based on the ambient temperature of the battery to obtain the calibrated resistance, including: obtaining the resistance of the detection resistor at the ambient temperature; determining the resistance calibration coefficient corresponding to the ambient temperature based on the ambient temperature and a predetermined resistance calibration coefficient-temperature correspondence relationship; obtaining the calibration coefficient according to the resistance of the detection resistor at the ambient temperature and the resistance calibration coefficient corresponding to the ambient temperature. The method comprises the steps of: calibrating a voltage difference across the detection resistor to obtain a calibrated voltage difference, wherein the detection circuit is connected to the battery and is configured to detect a current flowing through the battery, the detection circuit comprises a detection resistor and a voltage detector, the detection resistor is connected to the battery, the voltage detector is configured to detect a voltage difference across the detection resistor, the current flowing through the battery is determined according to the resistance value of the detection resistor and the voltage difference across the detection resistor, and comprises a discharge current or a charge current of the battery; based on at least one of the calibrated resistance value and the calibrated voltage difference, calibrating the current flowing through the battery to obtain a calibrated current; and integrating the calibrated current in ampere-hours to obtain a remaining capacity of the battery.

[0015] An embodiment of the third aspect of the present application provides a battery pack, which includes a battery and the battery management system in the above embodiment.

[0016] An embodiment of the fourth aspect of the present application provides an electrical device, which includes the battery pack in the above embodiment.

[0017] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In the accompanying drawings, unless otherwise specified, the same reference numerals throughout the multiple drawings represent the same or similar parts or elements. These drawings are not necessarily drawn to scale. It should be understood that these drawings only depict some embodiments disclosed in the present application and should not be regarded as limiting the scope of the present application.

[0019] Figure 1 A schematic diagram of the structure of a vehicle according to some embodiments of the present application;

[0020] Figure 2 A schematic block diagram of a battery management system according to some embodiments of the present application;

[0021] Figure 3A schematic diagram of a flow chart for determining a resistance calibration coefficient-temperature correspondence relationship in some embodiments of the present application;

[0022] Figure 4 A schematic diagram of a process for determining a first voltage calibration coefficient in some embodiments of the present application;

[0023] Figure 5 A schematic diagram of a flow chart for determining a first voltage calibration coefficient-temperature correspondence relationship in some embodiments of the present application;

[0024] Figure 6 A schematic diagram of a flow chart for determining a second voltage calibration coefficient-temperature correspondence relationship in some embodiments of the present application;

[0025] Figure 7 A flowchart of a battery management method according to some embodiments of the present application is shown. DETAILED DESCRIPTION

[0026] The following embodiments of the technical solution of the present application are described in detail in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present application, and are therefore only used as examples, and cannot be used to limit the scope of protection of the present application.

[0027] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" in the specification and claims of this application and the above-mentioned figure descriptions and any variations thereof are intended to cover non-exclusive inclusions.

[0028] In the description of the embodiments of the present application, the technical terms "first", "second", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present application, the meaning of "multiple" is more than two, unless otherwise clearly and specifically defined.

[0029] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0030] In the description of the embodiments of the present application, the term "and / or" is only a description of the association relationship of the associated objects, indicating that there may be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0031] In the description of the embodiments of the present application, the term "multiple" refers to more than two (including two). Similarly, "multiple groups" refers to more than two groups (including two groups), and "multiple pieces" refers to more than two pieces (including two pieces).

[0032] In the description of the embodiments of the present application, the technical terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, which are only for the convenience of describing the embodiments of the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the embodiments of the present application.

[0033] In the description of the embodiments of the present application, unless otherwise clearly specified and limited, technical terms such as "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the internal connection of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0034] At present, from the perspective of market development, the application of power batteries is becoming more and more extensive. Power batteries are not only used in energy storage power systems such as hydropower, thermal power, wind power and solar power stations, but also widely used in electric vehicles such as electric bicycles, electric motorcycles, electric cars, as well as military equipment and aerospace and other fields. With the continuous expansion of the application field of power batteries, the market demand is also constantly expanding.

[0035] The remaining capacity of a battery (State of Charge, SOC for short) is the ratio of the available power in the battery to the nominal capacity. During the use of the battery, the remaining power needs to be detected. The accuracy of SOC detection is related to the safety, reliability and service life of the battery. With the rapid development of power batteries, as a key component of new energy vehicles, the improvement of the SOC detection accuracy of power batteries is also a development demand of new energy vehicles.

[0036] For SOC detection, the ampere-hour integration method is usually used, that is, the battery charge change is calculated by integrating current and time, thereby calculating the battery SOC. In this detection method, as the usage time increases, the current error gradually accumulates, which will cause the SOC detection accuracy to deteriorate.

[0037] In order to obtain more accurate SOC detection results, the accuracy of the current can be improved, thereby reducing the cumulative error of the current in the ampere-hour integration method and improving the detection accuracy of the SOC.

[0038] Based on the above considerations, since the current is determined according to the voltage value and the resistance value, the current detection accuracy can be improved by reducing the resistance error of the detection resistor and / or the voltage difference error across the detection resistor, thereby further improving the SOC detection accuracy.

[0039] The battery management system disclosed in the embodiment of the present application can be used in, but not limited to, electrical devices such as vehicles, ships or aircraft. The battery management system disclosed in the present application can be used in the power supply system of the electrical device, which is conducive to improving the detection accuracy of the remaining battery power in the electrical device.

[0040] The embodiment of the present application provides an electric device using a battery management system, and the electric device may be, but is not limited to, a mobile phone, a tablet, a laptop, an electric toy, an electric tool, a battery car, an electric car, a ship, a spacecraft, etc. Among them, the electric toy may include a fixed or mobile electric toy, such as a game console, an electric car toy, an electric ship toy, and an electric airplane toy, etc., and the spacecraft may include an airplane, a rocket, a space shuttle, a spacecraft, etc.

[0041] For the convenience of description, the following embodiments are described by taking a vehicle 1000 as an example of an electrical device according to an embodiment of the present application.

[0042] Please refer to Figure 1 , Figure 1 A schematic diagram of the structure of a vehicle provided for some embodiments of the present application. Vehicle 1000 may be a fuel vehicle, a gas vehicle or a new energy vehicle, and the new energy vehicle may be a pure electric vehicle, a hybrid vehicle or an extended-range vehicle, etc. A battery pack 100 is provided inside the vehicle 1000, and the battery pack 100 may be provided at the bottom, head or tail of the vehicle 1000. The battery pack 100 may be used to power the vehicle 1000, for example, the battery pack 100 may be used as an operating power source for the vehicle 1000. The vehicle 1000 may also include a controller 200 and a motor 300, and the controller 200 is used to control the battery pack 100 to power the motor 300, for example, for the starting, navigation and working power requirements of the vehicle 1000 during driving.

[0043] In some embodiments of the present application, the battery pack 100 can not only serve as the operating power source of the vehicle 1000, but also serve as the driving power source of the vehicle 1000, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000.

[0044] The present application embodiment provides a battery management system. Figure 2 The battery management system 120 includes a detection circuit 121 and a controller (not shown).

[0045] The detection circuit 121 is connected to the battery 110 and is configured to detect the current flowing through the battery. The detection circuit 121 includes a detection resistor 1211 and a voltage detector 1212 .

[0046] The detection resistor 1211 is connected to the battery 110 . The voltage detector 1212 is configured to detect a voltage difference across the detection resistor 1211 .

[0047] The current flowing through the battery is determined according to the resistance of the detection resistor 1211 and the voltage difference across the detection resistor 1211 , and includes the discharge current or the charge current of the battery 110 .

[0048] The controller is configured to:

[0049] Calibrate at least one of the resistance value of the detection resistor 1211 and the voltage difference across the detection resistor 1211 to obtain at least one of the calibrated resistance value and the calibrated voltage difference;

[0050] Based on at least one of the calibrated resistance value and the calibrated voltage difference, calibrate the current flowing through the battery to obtain a calibrated current;

[0051] The calibrated current is integrated in ampere-hours to obtain the remaining power of the battery 110 .

[0052] In the embodiments of the present application, the term "battery" may include a battery cell, or a series, parallel or hybrid structure of multiple battery cells (eg, a battery module, etc.).

[0053] Since the voltage difference across the resistor can be obtained relatively easily, the current detection can be achieved by using the resistance value of the detection resistor and the voltage difference across the resistor. The detection resistor 1211 can use a shunt resistor, etc. The voltage detector 1212 can use an analog to digital converter (ADC for short). For different batteries 110, detection resistors and voltage detectors with different models and specifications can be selected. When the discharge current or charging current of the battery 110 flows through the detection resistor 1211, the current size can be calculated by measuring the voltage difference across the detection resistor 1211. Figure 2 An example of the detection circuit 121 is shown. The detection resistor 1211 is connected in series with the battery 110, and the current flowing through the detection resistor 1211 is the current flowing through the battery. According to the resistance R of the detection resistor 1211 and the voltage difference U at both ends, the current flowing through the battery I=U / R can be calculated.

[0054] In order to improve the detection accuracy of the current and reduce the cumulative error in the ampere-hour integration, the resistance R of the detection resistor 1211 and / or the voltage difference U at both ends can be calibrated to obtain the calibrated resistance R0 and / or the calibrated voltage difference U0, and further the calibrated current I0 can be obtained. For example, when only the resistance R is calibrated, the calibrated current I0=U / R0; when only the voltage difference U is calibrated, the calibrated current I0=U0 / R; when both the resistance R and the voltage difference U are calibrated, the calibrated current I0=U0 / R0.

[0055] After the calibrated current I0 is obtained, the remaining power of the battery 110 can be obtained by integrating the ampere-hours.

[0056] Using the ampere-hour integration method to obtain the remaining power of the battery 110 may require the ampere-hour integration of the current in multiple charge and discharge cycles. After obtaining the calibrated resistance value R0 and / or the calibrated voltage difference U0, for the charging stage and the discharging stage in each cycle, since the same resistance value R0 and / or voltage difference U0 are used to calculate the calibrated current I0, the current error in the charging stage and the current error in the discharging stage can offset each other, thereby reducing the cumulative error generated by the ampere-hour integration of the current. While reducing the absolute error of current detection, the relative error of the charging stage and the discharging stage in each charge and discharge cycle can also be reduced, further improving the detection accuracy of the remaining power.

[0057] In some embodiments, the detection circuit 121 and / or the controller may be disposed in a battery management unit (BMU for short).

[0058] It should be understood that although Figure 2 It is shown as being connected in series with the battery 110, but in other occasions, the form of the detection circuit 121 and the connection method with the battery 110 can be designed according to the use requirements, as long as the function of determining the current according to the resistance value and the voltage difference can be realized, and the present disclosure does not limit this.

[0059] The remaining capacity of the battery is obtained by integrating the current in ampere-hours. The detection error of the current flowing through the battery is reduced by reducing the error of the detection resistor value and / or reducing the error of the voltage difference across the detection resistor, thereby reducing the accumulated error in integrating the current in ampere-hours and improving the detection accuracy of the remaining capacity.

[0060] According to some embodiments of the present application, at least one of the resistance value of the detection resistor 1211 and the voltage difference across the detection resistor 1211 is calibrated, and obtaining at least one of the calibrated resistance value and the calibrated voltage difference includes at least one of the following items:

[0061] Based on the ambient temperature of the battery 110, the resistance value of the detection resistor 1211 is calibrated to obtain a calibrated resistance value;

[0062] The voltage difference across the detection resistor 1211 is calibrated to obtain a calibrated voltage difference.

[0063] In the embodiments of the present application, the term "ambient temperature" may indicate the temperature of the environment in which the battery is calibrated. The representation of the ambient temperature may be selected according to the use requirements. For example, in some embodiments, the ambient temperature may be represented by a specific temperature value, such as the temperature of the environment in which the battery is calibrated is 30 degrees Celsius (°C); in other embodiments, it may also be represented by a certain temperature range, such as the temperature of the environment in which the battery is calibrated is within a temperature range of 25°C to 35°C.

[0064] Since the resistance accuracy of the detection resistor 1211 is greatly affected by temperature, the resistance R may change nonlinearly with temperature changes, resulting in a large error in current detection. Therefore, the resistance R can be calibrated based on the ambient temperature of the battery 110, that is, the ambient temperature of the detection circuit 121, to obtain the calibrated resistance R0.

[0065] As for the voltage difference U across the detection resistor 1211, since it is sampled by the voltage detector 1212, the voltage detector 1212 itself will also have a certain detection error. In addition to calibration based on ambient temperature, the voltage difference U can also be calibrated based on the detection accuracy of the voltage detector 1212 itself.

[0066] The specific principle of the resistance R and voltage difference U calibration will be described in detail below.

[0067] By calibrating the resistance value of the detection resistor according to the ambient temperature, the detection error of the resistance value can be reduced. By calibrating the voltage difference across the detection resistor, the detection error of the voltage difference can be reduced. This can improve the detection accuracy of the current and further improve the detection accuracy of the remaining power.

[0068] According to some embodiments of the present application, based on the ambient temperature of the battery 110, the resistance value of the detection resistor 1211 is calibrated, and the calibrated resistance value is obtained including:

[0069] Obtaining the resistance value of the detection resistor 1211 at ambient temperature;

[0070] Determine a resistance calibration coefficient corresponding to the ambient temperature based on the ambient temperature and a predetermined resistance calibration coefficient-temperature correspondence relationship;

[0071] The calibrated resistance value is obtained according to the resistance value of the detection resistor 1211 at the ambient temperature and the resistance calibration coefficient corresponding to the ambient temperature.

[0072] For the detection resistor 1211, a resistor whose resistance value changes less when the temperature changes, that is, a low TCR resistor, can be selected.

[0073] For the detection resistor 1211 used in the detection circuit 121, the resistance calibration coefficient-temperature correspondence corresponding to the resistor can be predetermined. The process of determining the resistance calibration coefficient-temperature correspondence will be described in detail below. According to the ambient temperature, the resistance calibration coefficient y corresponding to the ambient temperature is determined. The resistance Rt of the detection resistor 1211 at ambient temperature can be obtained in different ways, for example, it can be inferred based on the working curve in the device manual of the detection resistor 1211, or measured using an instrument such as a resistance detector. The present disclosure does not limit the resistance acquisition method. Use the resistance calibration coefficient y to calibrate the resistance Rt of the detection resistor 1211 at ambient temperature to obtain a calibrated resistance R0=Rt×y.

[0074] Under different ambient temperatures, using different resistance calibration coefficients to calibrate the resistance of the detection resistor can reduce the detection error of the resistance under different temperatures and improve the detection accuracy.

[0075] According to some embodiments of the present application, the resistance calibration coefficient-temperature correspondence relationship is predetermined according to the first process 400. Figure 3 , the first process 400 includes steps 410 to 440.

[0076] Step 410, obtaining a reference resistance value. The reference resistance value indicates the resistance value of the detection resistor 1211 at a first temperature.

[0077] Step 420, obtaining the resistance value of the detection resistor 1211 at multiple temperatures.

[0078] Step 430 , determining resistance calibration coefficients corresponding to the multiple temperatures respectively according to the resistance values ​​of the detection resistor 1211 at the multiple temperatures and the reference resistance value.

[0079] Step 440 , fitting the multiple temperatures and the resistance calibration coefficients corresponding to the multiple temperatures, to obtain a resistance calibration coefficient-temperature correspondence relationship.

[0080] In step 410, the first temperature can be selected according to the use requirements, for example, according to the operating temperature range or operating curve of the detection resistor 1211. In one example, the first temperature can be determined to be 25°C, and the reference resistance Rc is the resistance of the detection resistor 1211 at 25°C.

[0081] In step 420, multiple temperatures for obtaining resistance values ​​can also be selected according to usage requirements. In one example, multiple temperatures can be determined within a temperature range of -40°C to 170°C. For each selected temperature tn, the resistance Rn of the detection resistor 1211 at that temperature is determined respectively. The more temperatures selected, the more accurate the resistance calibration coefficient-temperature correspondence obtained. As described above, the reference resistance Rc in step 410 and the resistance Rn at multiple temperatures in step 420 can be obtained in different ways, and the present disclosure does not limit this.

[0082] In step 430, for each resistance value Rn obtained in step 420, a resistance calibration coefficient yn corresponding thereto may be determined. In one example, the resistance calibration coefficient yn corresponding to the resistance value Rn at a certain temperature tn may be calculated by the following formula:

[0083] yn = (Rn-Rc) / Rc,

[0084] In the formula, yn represents the resistance calibration coefficient at a certain temperature, Rn represents the resistance of the detection resistor 1211 at the temperature, and Rc represents the reference resistance of the detection resistor 1211 at the first temperature.

[0085] In step 440, the resistance calibration coefficient-temperature correspondence relationship can be obtained by fitting according to the selected multiple temperatures tn and the resistance calibration coefficient yn corresponding to each temperature. The fitting method can be selected according to the use requirements, for example, linear fitting or nonlinear fitting can be used.

[0086] In one example, the resistance calibration coefficient-temperature correspondence relationship can be expressed by the following formula:

[0087] y=At 2 +Bt+C+1,

[0088] Where y represents the resistance calibration coefficient, t represents the temperature, and A, B, and C are fitting coefficients, which can be determined by fitting multiple temperatures tn and the corresponding resistance calibration coefficients yn.

[0089] As described above, after obtaining the corresponding relationship between the resistance calibration coefficient and the temperature, the corresponding temperature calibration coefficient y can be determined according to the ambient temperature, and the calibrated resistance R0 can be further obtained.

[0090] According to the current calculation formula I=U / R, after obtaining the calibrated resistance value R0, it can be combined with the calibrated voltage difference U0 to calculate the calibrated current I0; in the scenario where only the resistance value R is calibrated, the calibrated current I0 can be obtained using calculation software or other programs. For example, the parameters for the voltage difference can be pre-written in the software, and I0=CNTi×Ulsb / R0 can be calculated, where CNTi represents the sampled value of the voltage difference, and Ulsb represents the voltage sampling calibration parameter.

[0091] The resistance values ​​and reference resistance values ​​at multiple temperatures are obtained in advance, and the resistance calibration coefficient-temperature correspondence is further fitted, so that the resistance calibration coefficient corresponding to different ambient temperatures can be determined to achieve the calibration of the resistance values ​​at different temperatures.

[0092] According to some embodiments of the present application, the voltage difference across the detection resistor 1211 is calibrated, and the calibrated voltage difference includes at least one of the following items:

[0093] Calibrate the voltage difference across the detection resistor 1211 according to a predetermined first voltage calibration coefficient to obtain a calibrated voltage difference;

[0094] Based on the ambient temperature, the voltage difference across the detection resistor 1211 is calibrated to obtain a calibrated voltage difference.

[0095] Similar to the process of obtaining the calibrated resistance value R0, the calibrated voltage difference U0 can also be obtained based on the ambient temperature.

[0096] In addition, the calibrated voltage difference U0 can also be obtained according to a predetermined first voltage calibration system. It should be understood that the first voltage calibration coefficient can be a single coefficient or a combination of a group of coefficients.

[0097] In one example, the first voltage calibration coefficient is obtained according to linear fitting, and includes two coefficients K and B. The method for determining the first voltage calibration coefficient will be described in detail below.

[0098] By calibrating the voltage difference across the detection resistor according to the first voltage calibration coefficient and / or the ambient temperature, a detection error of the voltage difference can be reduced and detection accuracy can be improved.

[0099] According to some embodiments of the present application, the first voltage calibration coefficient is predetermined according to the second process 500. Figure 4 , the second process 500 includes steps 510 to 540.

[0100] In step 510, a plurality of currents with a plurality of current values ​​are applied to the detection resistor 1211. The plurality of currents correspond to the plurality of current values ​​one by one.

[0101] Step 520 , obtaining current values ​​flowing through the detection resistor 1211 corresponding to the multiple currents.

[0102] Step 530 , fitting the multiple current values ​​and the current values ​​flowing through the detection resistor 1211 corresponding to the multiple currents to obtain a fitting result.

[0103] Step 540: Determine a first voltage calibration coefficient according to the fitting result.

[0104] Since the resistance of the detection resistor is usually small, the current mainstream detection resistor resistance includes specifications such as 0.1 milliohms (mΩ), 0.15mΩ, and 0.25mΩ. Therefore, the voltage difference across the detection resistor is usually small, and the error during measurement is relatively large. In order to obtain a more accurate first voltage calibration coefficient, the voltage calibration process can be converted into a current calibration process, and different currents are applied to the detection resistor 1211, and the first voltage calibration coefficient is determined according to the current flowing through the detection resistor 1211.

[0105] The multiple current values ​​in step 510 can be determined for different voltage detectors according to the performance of the voltage detector. In some embodiments, the current range that the voltage detector 1212 can withstand can be segmented according to the gain of the voltage detector 1212, the current range that it can withstand, etc., and at least one current value I1 is determined in each current range.

[0106] In step 510, a current generating instrument (e.g., a current source, etc.) is used to apply a current to the detection resistor 1211 at a determined current value I1. In step 520, a current detection instrument with a higher detection accuracy (e.g., a current sensor with an accuracy of 0.01% or more, etc.) may be used to detect the current value I2 flowing through the detection resistor 1211. For each current value I1, a corresponding current value I2 is obtained.

[0107] In step 530, a linear fit may be performed on each group of corresponding current values ​​I1 and I2. For example, a fitting result may be obtained according to the following formula:

[0108] I2=K×I1+B,

[0109] In the formula, I1 represents the current value applied to the detection resistor 1211, I2 represents the current value obtained flowing through the detection resistor 1211, K and B are first voltage calibration coefficients, which can be obtained by fitting multiple groups of corresponding current values ​​I1 and current values ​​I2.

[0110] After determining the first voltage calibration coefficient (ie, K, B values), the calibrated voltage difference U0 can be determined according to the first voltage calibration coefficient and the voltage difference U across the detection resistor 1211 detected by the voltage detector 1212. In one example, the calibrated voltage difference U0=K×U+B.

[0111] In some embodiments, since charging current and discharging current will flow through the detection resistor 1211 during the detection process of the remaining power, the current applied to the detection resistor 1211 in step 510 may also include two currents flowing in two directions, namely, a forward current and a reverse current. For the forward current and the reverse current, the first voltage calibration coefficients corresponding to each other can be determined respectively, namely, K-forward, B-forward, K-reverse, and B-reverse. Depending on whether the battery 110 is in a charging state or a discharging state, the voltage difference U across the detection resistor 1211 is calibrated using K-forward, B-forward, or using K-reverse, B-reverse, to obtain the calibrated voltage difference U0.

[0112] In some embodiments, after determining the first voltage calibration coefficient, it can be verified. For example, when the current generating instrument applies current to the detection resistor 1211 at the determined current value I1, the controller obtains the current value I1' based on the obtained first voltage calibration coefficient, and by comparing the error between the current value I1' obtained by the controller and the current value I2 flowing through the detection resistor 1211 detected by the current detection instrument, it can be verified whether the obtained first voltage calibration coefficient is sufficiently accurate.

[0113] By applying currents of different current values ​​to the detection resistor and determining the set value and the detection value of the current applied to the detection resistor, the voltage calibration process is converted into a current calibration process, so that the voltage calibration coefficient can be accurately determined when the voltage is small, thereby improving the detection accuracy of the voltage difference.

[0114] According to some embodiments of the present application, the voltage difference across the detection resistor 1211 is calibrated according to a predetermined first voltage calibration coefficient, and the calibrated voltage difference is obtained including:

[0115] Determine a first voltage calibration coefficient corresponding to the ambient temperature based on the ambient temperature and a predetermined first voltage calibration coefficient-temperature correspondence relationship;

[0116] The voltage difference across the detection resistor 1211 is calibrated according to the first voltage calibration coefficient corresponding to the ambient temperature to obtain a calibrated voltage difference.

[0117] Since the voltage detector 1212 may have nonlinear errors, temperature drift errors, etc. during use as the ambient temperature changes, resulting in inaccurate detection of the voltage difference, therefore, for the first voltage calibration coefficient determined above, a correspondence between the first voltage calibration coefficient and temperature can be further established, thereby reducing the voltage difference detection error caused by the ambient temperature.

[0118] In an embodiment where the first voltage calibration coefficient includes a set of coefficients, for each coefficient therein, the correspondence between it and the temperature can be determined respectively. For example, when the first voltage calibration coefficient includes two coefficients K and B, the K-temperature correspondence and the B-temperature correspondence can be determined respectively.

[0119] According to the first voltage calibration coefficient-temperature correspondence, the first voltage calibration coefficient corresponding to the current ambient temperature can be determined, and the voltage difference U across the detection resistor 1211 is calibrated using the first voltage calibration coefficient to obtain the calibrated voltage difference U0.

[0120] After the first voltage calibration coefficient is obtained, the first voltage calibration coefficient under different ambient temperatures is further determined to further improve the detection accuracy of the voltage difference.

[0121] According to some embodiments of the present application, the first voltage calibration coefficient-temperature correspondence relationship is predetermined according to the third process 600. Figure 5 , the third process 600 includes steps 610 to 620.

[0122] Step 610: determine first voltage calibration coefficients corresponding to a plurality of temperatures.

[0123] Step 620 , fitting the multiple temperatures and the first voltage calibration coefficients corresponding to the multiple temperatures respectively, to obtain a first voltage calibration coefficient-temperature correspondence relationship.

[0124] At multiple temperatures, the first voltage calibration coefficient at the temperature is determined according to the second process 500 described above. In step 620, the first voltage calibration coefficient-temperature correspondence relationship can be obtained by fitting according to the multiple temperatures and the first voltage calibration coefficients respectively corresponding thereto. The fitting method can be selected according to the use requirements, for example, linear fitting or nonlinear fitting can be used. In some embodiments, the process of fitting the first voltage calibration coefficient-temperature correspondence relationship can refer to the process of obtaining the resistance calibration coefficient-temperature correspondence relationship, which will not be repeated here.

[0125] By fitting multiple temperatures and first voltage calibration coefficients respectively corresponding to the multiple temperatures, the first voltage calibration coefficients corresponding to different ambient temperatures can be determined, thereby achieving calibration of voltage differences at different temperatures.

[0126] According to some embodiments of the present application, based on the ambient temperature, the voltage difference across the detection resistor 1211 is calibrated to obtain the calibrated voltage difference, which includes:

[0127] Obtaining a voltage difference between two ends of the detection resistor 1211 at ambient temperature;

[0128] Determine a second voltage calibration coefficient corresponding to the ambient temperature based on the ambient temperature and a predetermined second voltage calibration coefficient-temperature correspondence relationship;

[0129] The calibrated voltage difference is obtained according to the voltage difference between the two ends of the detection resistor 1211 at the ambient temperature and the second voltage calibration coefficient corresponding to the ambient temperature.

[0130] Similar to the calibration process of the resistance R of the detection resistor 1211 , the calibration of the voltage difference U across the detection resistor 1211 may also be performed only based on the ambient temperature.

[0131] For the detection resistor 1211 used in the detection circuit 121, the second voltage calibration coefficient-temperature correspondence corresponding to the resistor can be predetermined. According to the ambient temperature, the corresponding second voltage calibration coefficient z is determined. The voltage difference Ut across the detection resistor 1211 at the ambient temperature can be detected by the voltage detector 1212. The voltage difference Ut across the detection resistor 1211 at the ambient temperature is calibrated using the second voltage calibration coefficient z to obtain the calibrated voltage difference U0=Ut×z.

[0132] Under different ambient temperatures, different second voltage calibration coefficients are used to calibrate the voltage difference across the detection resistor, which can reduce the detection error of the voltage difference under different temperatures and improve the detection accuracy.

[0133] According to some embodiments of the present application, the second voltage calibration coefficient-temperature correspondence relationship is predetermined according to the fourth process 700. Figure 6 , the fourth process 700 includes steps 710 to 740.

[0134] Step 710, obtaining a reference voltage difference. The reference voltage difference indicates a voltage difference between two ends of the detection resistor 1211 at a second temperature.

[0135] Step 720 , obtaining the voltage difference between two ends of the detection resistor 1211 at multiple temperatures.

[0136] Step 730 , determining second voltage calibration coefficients corresponding to the multiple temperatures respectively according to the voltage difference across the detection resistor 1211 at the multiple temperatures and the reference voltage difference.

[0137] Step 740 , fitting the multiple temperatures and the second voltage calibration coefficients corresponding to the multiple temperatures respectively, to obtain a second voltage calibration coefficient-temperature correspondence relationship.

[0138] The process of determining the second voltage calibration coefficient-temperature correspondence relationship may refer to the first process 400 , ie, the process of determining the resistance calibration coefficient-temperature correspondence relationship.

[0139] In step 710, the second temperature can be selected according to the use requirements, for example, according to the operating temperature range or operating curve of the detection resistor 1211. The reference voltage difference Uc is the voltage difference across the detection resistor 1211 at the second temperature.

[0140] In step 720, multiple temperatures tm for obtaining the voltage difference can also be selected according to the use requirements. For each selected temperature tm, the voltage difference Un at the two ends of the detection resistor 1211 at the temperature is determined respectively. The more temperatures are selected, the more accurate the second voltage calibration coefficient-temperature correspondence is obtained. The reference voltage difference Uc in step 710 and the voltage difference Un at multiple temperatures in step 720 can be obtained in different ways, for example, it can be inferred based on the working curve in the manual of the detection resistor 1211 device, or measured using an instrument such as a voltage detector, and the present disclosure does not limit this.

[0141] In step 730, a second voltage calibration coefficient corresponding to each voltage difference Un obtained in step 720 may be determined. In one example, the determination process of the resistance calibration coefficient in step 430 may be referred to, and will not be described in detail here.

[0142] In step 740, according to the selected multiple temperatures tm and the second voltage calibration coefficient corresponding to each temperature, the second voltage calibration coefficient-temperature correspondence relationship can be fitted. The fitting method can be selected according to the use requirements, for example, linear fitting or nonlinear fitting can be used. In an example, the determination process of the resistance calibration coefficient-temperature correspondence relationship in step 440 can be referred to, which will not be repeated here.

[0143] As described above, after obtaining the second voltage calibration coefficient-temperature correspondence relationship, the corresponding second voltage calibration coefficient can be determined according to the ambient temperature, and the calibrated voltage value U0 can be further obtained.

[0144] The voltage difference and the reference voltage difference at multiple temperatures are obtained in advance, and the second voltage calibration coefficient-temperature correspondence is further fitted, so that the second voltage calibration coefficient corresponding to different ambient temperatures can be determined to achieve calibration of the voltage difference at different temperatures.

[0145] Based on the same technical concept, the embodiment of the present application provides a battery management method. The embodiment of the battery management method can refer to the embodiment of the battery management system, and the repeated parts will not be repeated. Figure 7 , the battery management method 800 includes steps 810 to 830.

[0146] Step 810 , calibrate at least one of the resistance of the detection resistor 1211 in the detection circuit 121 and the voltage difference across the detection resistor 1211 to obtain at least one of the calibrated resistance and the calibrated voltage difference.

[0147] Step 810 includes at least one of the following:

[0148] Based on the ambient temperature of the battery 110, the resistance value of the detection resistor 1211 is calibrated to obtain a calibrated resistance value;

[0149] The voltage difference across the detection resistor 1211 is calibrated to obtain a calibrated voltage difference.

[0150] Based on the ambient temperature of the battery 110, the resistance value of the detection resistor 1211 is calibrated, and the calibrated resistance value includes:

[0151] Obtaining the resistance value of the detection resistor 1211 at ambient temperature;

[0152] Determine a resistance calibration coefficient corresponding to the ambient temperature based on the ambient temperature and a predetermined resistance calibration coefficient-temperature correspondence relationship;

[0153] The calibrated resistance value is obtained according to the resistance value of the detection resistor 1211 at the ambient temperature and the resistance calibration coefficient corresponding to the ambient temperature.

[0154] The detection circuit 121 is connected to the battery 110 and is configured to detect the current flowing through the battery. The detection circuit 121 includes a detection resistor 1211 and a voltage detector 1212. The detection resistor 1211 is connected to the battery 110, and the voltage detector 1212 is configured to detect the voltage difference across the detection resistor 1211. The current flowing through the battery is determined according to the resistance value of the detection resistor 1211 and the voltage difference across the detection resistor 1211, and includes the discharge current or the charge current of the battery 110.

[0155] Step 820, calibrating the current flowing through the battery based on at least one of the calibrated resistance value and the calibrated voltage difference to obtain a calibrated current.

[0156] Step 830 , integrating the calibrated current in ampere-hours to obtain the remaining power of the battery 110 .

[0157] The process of determining the remaining power of the battery 110 has been described in detail above, and for the sake of brevity, it will not be repeated here.

[0158] The remaining capacity of the battery is obtained by integrating the current in ampere-hours. By reducing the error of the detection resistor value and / or reducing the error of the voltage difference across the detection resistor, the detection error of the current flowing through the battery is reduced, thereby reducing the accumulated error in the ampere-hour integration of the current and improving the detection accuracy of the remaining capacity.

[0159] Based on the same technical concept, the embodiment of the present application provides a battery pack. The battery pack 100 includes a battery 110 and the battery management system 120 in the above embodiment.

[0160] Based on the same technical concept, an embodiment of the present application provides an electric device, which includes the battery pack 100 in the above embodiment.

[0161] As mentioned above, the electrical device includes but is not limited to a vehicle, a ship or an aircraft. The configuration of the electrical device and the battery pack 100 can refer to Figure 1 The examples shown are not repeated here.

[0162] A specific embodiment of the present application is described below. It should be understood that this specific embodiment is described for illustrative purposes only and should not be interpreted as limiting the present application.

[0163] like Figure 2 As shown, the battery management system 120 includes a detection circuit 121 and a controller. A detection resistor 1211 in the detection circuit 121 is connected to the battery 110 , and a voltage detector 1212 can be used to detect a voltage difference between two ends of the detection resistor 1211 .

[0164] For the detection resistor 1211, a resistance calibration coefficient-temperature correspondence relationship can be predetermined to calibrate the resistance of the detection resistor 1211. For the voltage detector 1212, a first voltage calibration coefficient can be predetermined to calibrate the voltage difference across the detection resistor 1211.

[0165] In the process of determining the resistance calibration coefficient-temperature correspondence relationship, the reference resistance Rc at the first temperature and the resistance Rn of the detection resistor 1211 at multiple temperatures tn may be obtained.

[0166] The first temperature may be determined to be 25 degrees Celsius (°C), and the reference resistance Rc is the resistance of the detection resistor 1211 at 25°C. Multiple temperatures tn may be determined in the temperature range of -40°C to 170°C. For each selected temperature tn, the resistance Rn of the detection resistor 1211 at the temperature is determined. For each resistance Rn obtained, the corresponding resistance calibration coefficient yn is determined:

[0167] yn = (Rn-Rc) / Rc,

[0168] In the formula, yn represents the resistance calibration coefficient at a certain temperature tn, Rn represents the resistance of the detection resistor 1211 at the temperature, and Rc represents the reference resistance of the detection resistor 1211 at the first temperature.

[0169] According to the selected multiple temperatures tn and the resistance calibration coefficient yn corresponding to each temperature, the resistance calibration coefficient-temperature correspondence relationship is fitted:

[0170] y=At 2 +Bt+C+1,

[0171] Where y represents the resistance calibration coefficient, t represents the temperature, and A, B, and C are fitting coefficients, which can be determined by fitting multiple temperatures tn and the corresponding resistance calibration coefficients yn.

[0172] After obtaining the above-mentioned resistance calibration coefficient-temperature correspondence relationship, the corresponding temperature calibration coefficient y and the resistance Rt of the detection resistor 1211 at the ambient temperature can be determined according to the ambient temperature, and the calibrated resistance R0=Rt×y can be further obtained.

[0173] In the process of determining the first voltage calibration coefficient, the voltage calibration process can be converted into a current calibration process. For different voltage detectors, multiple current values ​​can be determined according to the performance of the voltage detector. For example, the current range that the voltage detector 1212 can withstand can be segmented, and at least one current value I1 can be determined in each current range. Use a current generating instrument (for example, a current source, etc.) to apply current to the detection resistor 1211 to determine the current value I1, and use a current detection instrument with higher detection accuracy (for example, a current sensor with an accuracy of more than 0.01%, etc.) to detect the current value I2 flowing through the detection resistor 1211. For each current value I1, a corresponding current value I2 is obtained. Linear fitting is performed on each group of corresponding current values ​​I1 and current values ​​I2 to obtain the following fitting results:

[0174] I2=K×I1+B,

[0175] In the formula, I1 represents the current value applied to the detection resistor 1211, I2 represents the current value obtained flowing through the detection resistor 1211, K and B are first voltage calibration coefficients, which can be obtained by fitting multiple groups of corresponding current values ​​I1 and current values ​​I2.

[0176] After the first voltage calibration coefficient (ie, K and B values) is determined, the calibrated voltage difference U0 may be determined according to the first voltage calibration coefficient and the voltage difference U across the detection resistor 1211 detected by the voltage detector 1212 .

[0177] According to the current calculation formula I=U / R, if the calibrated resistance value R0 and the calibrated voltage difference U0 are obtained, the calibrated current I0=U0 / R0 can be calculated; if only the calibrated resistance value R0 is obtained, the calibrated current I0 can be obtained by using calculation software or other programs. For example, the parameters for the voltage difference can be pre-written in the software, and I0=CNTi×Ulsb / R0 can be calculated, where CNTi represents the sampling value of the voltage difference, and Ulsb represents the voltage sampling calibration parameter; if only the calibrated voltage difference U0 is obtained, the calibrated current I0=U0 / R can be calculated using the calibrated voltage difference U0 alone.

[0178] After the calibrated current is obtained, the ampere-hour integration is performed to obtain the accurate remaining capacity of the battery 110 .

[0179] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them; although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application, and they should all be included in the scope of the claims and specification of the present application. In particular, as long as there is no structural conflict, the various technical features mentioned in the various embodiments can be combined in any way. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions that fall within the scope of the claims.

Claims

1. A battery management system, characterized in that: include: A detection circuit is connected to the battery and is configured to detect a current flowing through the battery. The detection circuit comprises: A detection resistor connected to the battery; a voltage detector configured to detect a voltage difference across the detection resistor, Wherein, the current flowing through the battery is determined according to the resistance value of the detection resistor and the voltage difference across the detection resistor, and includes the discharge current or the charge current of the battery; The controller is configured as: Calibrate at least one of the resistance value of the detection resistor and the voltage difference across the detection resistor to obtain at least one of the calibrated resistance value and the calibrated voltage difference, including at least one of the following items: Based on the ambient temperature of the battery, the resistance value of the detection resistor is calibrated to obtain the calibrated resistance value, including: Obtaining the resistance value of the detection resistor at the ambient temperature; Determine the resistance calibration coefficient corresponding to the ambient temperature based on the ambient temperature and a predetermined resistance calibration coefficient-temperature correspondence relationship; Obtaining the calibrated resistance value according to the resistance value of the detection resistor at the ambient temperature and a resistance calibration coefficient corresponding to the ambient temperature; Calibrate the voltage difference across the detection resistor to obtain the calibrated voltage difference, including at least one of the following: Calibrate the voltage difference across the detection resistor according to a predetermined first voltage calibration coefficient to obtain the calibrated voltage difference, wherein the first voltage calibration coefficient is predetermined according to the following steps: Applying a plurality of currents to the detection resistor at a plurality of current values, respectively, the plurality of currents corresponding to the plurality of current values ​​one by one; Obtaining current values ​​flowing through the detection resistor corresponding to the multiple currents respectively; Fitting the multiple current values ​​and the current values ​​flowing through the detection resistor respectively corresponding to the multiple currents to obtain a fitting result; Determining the first voltage calibration coefficient according to the fitting result; Based on the ambient temperature, calibrate the voltage difference across the detection resistor to obtain the calibrated voltage difference; Based on at least one of the calibrated resistance value and the calibrated voltage difference, calibrate the current flowing through the battery to obtain a calibrated current; The calibrated current is integrated in ampere-hours to obtain the remaining power of the battery.

2. The battery management system according to claim 1, characterized in that: The resistance calibration coefficient-temperature correspondence relationship is predetermined according to the following steps: Acquire a reference resistance value, where the reference resistance value indicates the resistance value of the detection resistor at a first temperature; Obtaining resistance values ​​of the detection resistor at multiple temperatures; Determining resistance calibration coefficients corresponding to the multiple temperatures respectively according to the resistance values ​​of the detection resistor at multiple temperatures and the reference resistance value; The multiple temperatures and the resistance calibration coefficients respectively corresponding to the multiple temperatures are fitted to obtain the resistance calibration coefficient-temperature correspondence relationship.

3. The battery management system according to claim 1, characterized in that: The step of calibrating the voltage difference across the detection resistor according to a predetermined first voltage calibration coefficient to obtain the calibrated voltage difference comprises: Determine a first voltage calibration coefficient corresponding to the ambient temperature based on the ambient temperature and a predetermined first voltage calibration coefficient-temperature correspondence relationship; The voltage difference across the detection resistor is calibrated according to a first voltage calibration coefficient corresponding to the ambient temperature to obtain the calibrated voltage difference.

4. The battery management system according to claim 3, characterized in that: The first voltage calibration coefficient-temperature correspondence relationship is predetermined according to the following steps: Determine the first voltage calibration coefficients corresponding to a plurality of temperatures respectively; The multiple temperatures and the first voltage calibration coefficients respectively corresponding to the multiple temperatures are fitted to obtain a corresponding relationship between the first voltage calibration coefficient and temperature.

5. The battery management system according to any one of claims 1 to 4, characterized in that: The step of calibrating the voltage difference across the detection resistor based on the ambient temperature to obtain the calibrated voltage difference comprises: Obtaining a voltage difference between two ends of the detection resistor at the ambient temperature; Determine a second voltage calibration coefficient corresponding to the ambient temperature based on the ambient temperature and a predetermined second voltage calibration coefficient-temperature correspondence relationship; The calibrated voltage difference is obtained according to the voltage difference between the two ends of the detection resistor at the ambient temperature and a second voltage calibration coefficient corresponding to the ambient temperature.

6. The battery management system according to claim 5, characterized in that: The second voltage calibration coefficient-temperature correspondence relationship is predetermined according to the following steps: Obtaining a reference voltage difference, where the reference voltage difference indicates a voltage difference between two ends of the detection resistor at a second temperature; Obtaining a voltage difference between two ends of the detection resistor at multiple temperatures; Determining second voltage calibration coefficients corresponding to the multiple temperatures respectively according to the voltage difference between two ends of the detection resistor at multiple temperatures and the reference voltage difference; The multiple temperatures and the second voltage calibration coefficients respectively corresponding to the multiple temperatures are fitted to obtain a corresponding relationship between the second voltage calibration coefficient and temperature.

7. A battery management method, characterized in that: include: Calibrate at least one of the resistance of the detection resistor in the detection circuit and the voltage difference across the detection resistor to obtain at least one of the calibrated resistance and the calibrated voltage difference, including at least one of the following items: calibrate the resistance of the detection resistor based on the ambient temperature of the battery to obtain the calibrated resistance, including: obtain the resistance of the detection resistor at the ambient temperature; determine the resistance calibration coefficient corresponding to the ambient temperature based on the ambient temperature and a predetermined resistance calibration coefficient-temperature correspondence; obtain the calibrated resistance according to the resistance of the detection resistor at the ambient temperature and the resistance calibration coefficient corresponding to the ambient temperature; calibrate the voltage difference across the detection resistor to obtain the calibrated voltage difference, including at least one of the following items: calibrate the voltage difference across the detection resistor based on a predetermined first voltage calibration coefficient to obtain the calibrated voltage difference, wherein the first voltage calibration coefficient is based on Predetermined according to the following steps: applying multiple currents to the detection resistor at multiple current values, the multiple currents corresponding to the multiple current values ​​one by one; obtaining the current values ​​flowing through the detection resistor corresponding to the multiple currents; fitting the multiple current values ​​and the current values ​​flowing through the detection resistor corresponding to the multiple currents to obtain fitting results; determining the first voltage calibration coefficient according to the fitting results; calibrating the voltage difference across the detection resistor based on the ambient temperature to obtain the calibrated voltage difference, wherein the detection circuit is connected to the battery and is configured to detect the current flowing through the battery, the detection circuit includes the detection resistor and a voltage detector, the detection resistor is connected to the battery, the voltage detector is configured to detect the voltage difference across the detection resistor, the current flowing through the battery is determined according to the resistance value of the detection resistor and the voltage difference across the detection resistor, and includes the discharge current or charge current of the battery; Based on at least one of the calibrated resistance value and the calibrated voltage difference, calibrate the current flowing through the battery to obtain a calibrated current; The calibrated current is integrated in ampere-hours to obtain the remaining power of the battery.

8. A battery pack, characterized in that: include: Battery; A battery management system as claimed in any one of claims 1 to 6.

9. An electrical device, characterized in that: Comprising the battery pack as claimed in claim 8.

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