A battery management system, a battery pack and a power utilization device

Abstract

The application provides a battery management system, a battery pack and a power utilization device. The battery management system comprises a micro control unit configured to be electrically connected with a battery module for acquiring a voltage of the battery module; further comprising a voltage detection circuit, a first voltage source and a second voltage source, the voltage detection circuit is configured to detect a voltage of an external charger; the voltage detection circuit comprises an operational amplifier, the first voltage source is electrically connected to the operational amplifier for supplying power to the operational amplifier, the second voltage source is electrically connected to a first input end of the operational amplifier, and an output end of the operational amplifier is electrically connected to the micro control unit; the voltage detection circuit further comprises a first resistor and a second resistor, a first end of the first resistor is electrically connected to a second input end of the operational amplifier, a second end of the first resistor is configured to be electrically connected with a negative terminal of the external charger and a negative electrode of the battery module, and the second resistor is electrically connected between the second input end of the operational amplifier and the output end of the operational amplifier.

Description

Technical Field

[0001] This application relates to the field of battery technology, and more specifically, to a battery management system, a battery pack, and an electrical device. Background Technology

[0002] During battery charging, the external charger first communicates with the Battery Management System (BMS). The BMS receives the charging signal sent by the charger and then controls the battery charging. However, if the communication between the external charger and the BMS malfunctions, the battery charging will also malfunction. Summary of the Invention

[0003] The purpose of this application is to provide a battery management system, a battery pack, and an electrical device for detecting the insertion or removal of a charger and for detecting the charging voltage of the charger.

[0004] In a first aspect, embodiments of this application provide a battery management system, including a microcontroller unit configured to be electrically connected to a battery module for acquiring the voltage of the battery module; further including a voltage detection circuit, a first voltage source, and a second voltage source, the voltage detection circuit being used to detect the voltage of an external charger; the voltage detection circuit including an operational amplifier, the first voltage source being electrically connected to the operational amplifier for supplying power to the operational amplifier, the second voltage source being electrically connected to a first input terminal of the operational amplifier, and the output terminal of the operational amplifier being electrically connected to the microcontroller unit; the voltage detection circuit further including a first resistor and a second resistor, wherein a first terminal of the first resistor is electrically connected to a second input terminal of the operational amplifier, the second terminal of the first resistor is used to be electrically connected to the negative terminal of the external charger and the negative terminal of the battery module respectively, and the second resistor is electrically connected between the second input terminal and the output terminal of the operational amplifier.

[0005] In the technical solution of this application embodiment, the voltage of the external charger is detected by a voltage detection circuit. In the voltage detection circuit, one end of the first resistor is electrically connected to the second input terminal of the operational amplifier, and the other end is electrically connected between the negative terminal of the battery module and the second input terminal of the operational amplifier. The second resistor is electrically connected between the second input terminal and the output terminal of the operational amplifier. By using the voltages of the first voltage source, the second voltage source, and the battery module, as well as the "virtual open" and "virtual short" characteristics of the operational amplifier, the battery voltage difference between the negative terminal of the charger and the negative terminal of the battery module can be determined, thereby achieving effective and accurate detection of the external charger voltage.

[0006] In some embodiments, the second voltage source includes a voltage source that provides a reference voltage; or, the voltage detection circuit further includes a voltage divider branch electrically connected between the first voltage source and ground, wherein the voltage divider branch includes at least two resistors connected in series, wherein the node between the series resistors is electrically connected to the first input terminal of the operational amplifier.

[0007] In the technical solution of this application embodiment, the second voltage source can be a voltage source that provides a reference voltage; or it can be a voltage source formed by dividing the first voltage source; the second voltage source can provide a stable voltage input to the first input terminal of the operational amplifier.

[0008] In some embodiments, the battery management system further includes a charger detection circuit for electrical connection to the negative terminal of an external charger, and the charger detection circuit is also electrically connected to the first voltage source, the microcontroller unit, and ground; the microcontroller unit is configured to acquire an electrical signal output by the charger detection circuit to determine the electrical connection state between the external charger and the battery module, wherein the electrical connection state between the external charger and the battery module includes: the external charger being inserted into the battery module or the external charger being removed from the battery module.

[0009] In the technical solution of this application embodiment, a charger detection circuit detects whether an external charger is inserted, so that a first voltage source supplies power to the operational amplifier based on the insertion detection result. That is, voltage detection only begins after the charger is detected to be inserted. In this way, invalid detection when the charger is not inserted is avoided, reducing the amount of power supplied by the battery module to the voltage detection circuit on the battery management system, and reducing power consumption.

[0010] In some embodiments, the charger detection circuit includes a first switch and a second switch; the first switch is electrically connected to the second switch and ground respectively, and the first switch is also used to be electrically connected to the negative terminal of an external charger; the second switch is electrically connected to the first voltage source and the microcontroller unit respectively, and the second switch can perform on / off switching in response to the on / off switching of the first switch.

[0011] In the technical solution of this application embodiment, the accurate detection of whether an external charger is inserted is achieved through a first switch and a second switch.

[0012] In some embodiments, the charger detection circuit further includes a first diode, wherein the negative terminal of the first diode is electrically connected to the negative terminal of an external charger, and the positive terminal of the first diode is electrically connected to the first switch.

[0013] In the technical solution of this application embodiment, the first diode is used to prevent reverse voltage and overvoltage, thereby ensuring the safety of the charging detection circuit.

[0014] In some embodiments, the charger detection circuit further includes: a third resistor, a fourth resistor, a fifth resistor, and a sixth resistor; the third resistor is electrically connected between the first switch and the second switch; the fourth resistor is electrically connected between the control terminal of the second switch and the first terminal of the second switch; the fifth resistor is electrically connected between the control terminal of the first switch and the first terminal of the first switch; and the sixth resistor is electrically connected between the control terminal of the first switch and ground.

[0015] In the technical solution of this application embodiment, the third resistor, the fourth resistor, the fifth resistor and the sixth resistor serve to limit current and match impedance.

[0016] In some embodiments, the charger detection circuit further includes: a seventh resistor, an eighth resistor, and a first capacitor; the seventh resistor is electrically connected between the second terminal of the second switch and ground; the eighth resistor and the first capacitor are connected in series between the second terminal of the second switch and ground, and the eighth resistor is also electrically connected to the microcontroller unit.

[0017] In the technical solution of this application embodiment, the seventh resistor can be used as a pull-down resistor to stabilize the voltage, and the eighth resistor and the first capacitor can be used for filtering. That is, the seventh resistor, the eighth resistor, and the first capacitor together form a filter circuit to achieve signal filtering and improve the accuracy of the detection results.

[0018] In some embodiments, the voltage detection circuit further includes a transient diode; the transient diode is connected to the first resistor and ground, respectively.

[0019] In this embodiment, the transient diode can serve as an anti-static device, providing a discharge circuit for external static electricity. It is electrically connected between the first resistor and ground, allowing the voltage detection circuit to discharge static electricity through the transient diode when static electricity occurs.

[0020] In some embodiments, the voltage detection circuit further includes a second diode, wherein the second diode is electrically connected between the second input terminal of the operational amplifier and ground.

[0021] In the technical solution of this application embodiment, the second diode can bypass the operational amplifier when a negative voltage appears at the negative terminal. The current flows through the second diode and the first resistor to the negative terminal, thus protecting the operational amplifier.

[0022] In some embodiments, the voltage detection circuit further includes a second capacitor; wherein the second capacitor is electrically connected between the second input terminal of the operational amplifier and the output terminal of the operational amplifier.

[0023] In the technical solution of this application embodiment, the transient voltage signal between the second input terminal and the output terminal of the operational amplifier can be filtered out by the second capacitor, thereby improving the accuracy of the detection results.

[0024] In some embodiments, the voltage detection circuit further includes a ninth resistor and a third capacitor; wherein the ninth resistor and the third capacitor are connected in series between the output terminal of the operational amplifier and ground, and the node between the ninth resistor and the third capacitor is electrically connected to the microcontroller unit.

[0025] In the technical solution of this application embodiment, the voltage detection circuit is filtered by the ninth resistor and the third capacitor, thereby improving the accuracy of the detection results.

[0026] Secondly, embodiments of this application provide a battery pack, including: a battery module and a battery management system of any one of the above, wherein the battery module includes at least one battery cell.

[0027] Thirdly, embodiments of this application provide an electrical device, including: a battery pack as described above. Attached Figure Description

[0028] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments of this application will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation on the scope.

[0029] Figure 1 This is a schematic diagram of a battery management system; Figure 2 A schematic diagram of a battery management system provided in an embodiment of this application; Figure 3 A schematic diagram of a voltage divider branch provided in an embodiment of this application; Figure 4 A schematic diagram of an optional battery management system provided for an embodiment of this application; Figure 5 A schematic diagram of an optional charger detection circuit provided in an embodiment of this application; Figure 6 A schematic diagram of yet another optional charger detection circuit provided in an embodiment of this application; Figure 7 A schematic diagram of yet another optional charger detection circuit provided in an embodiment of this application; Figure 8A schematic diagram of yet another optional charger detection circuit provided in an embodiment of this application; Figure 9 A schematic diagram of yet another optional charger detection circuit provided in an embodiment of this application; Figure 10 A schematic diagram of an optional voltage detection circuit provided in an embodiment of this application; Figure 11 A schematic diagram of yet another optional voltage detection circuit provided in an embodiment of this application; Figure 12 A schematic diagram of yet another optional voltage detection circuit provided in an embodiment of this application; Figure 13 A schematic diagram of yet another optional voltage detection circuit provided in an embodiment of this application; Figure 14 A schematic diagram of an optional battery management system implementation structure provided in an embodiment of this application; Figure 15 This is a schematic diagram of the battery pack structure provided in an embodiment of this application; Figure 16 This is a schematic diagram of the structure of the electrical device provided in the embodiments of this application. Detailed Implementation

[0030] The embodiments of the technical solution of this application will now be described in detail with reference to the accompanying drawings. These embodiments are only used to more clearly illustrate the technical solution of this application and are therefore merely examples, and should not be used to limit the scope of protection of this application.

[0031] 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 pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0032] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0033] In this document, the term "embodiment" 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.

[0034] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0035] In the description of the embodiments of this application, unless otherwise expressly specified and limited, the electrical connection between two elements can be a direct electrical connection or an indirect electrical connection achieved through an intermediate element. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of this application according to the specific circumstances.

[0036] Currently, judging from market trends, battery applications are becoming increasingly widespread. Batteries are not only used in energy storage systems such as 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 military equipment and aerospace. With the continuous expansion of battery applications, market demand is also constantly increasing.

[0037] During application, batteries need to be charged in a timely manner. The charging detection circuit in the Battery Management System (BMS) can be used to detect battery charging, including the insertion and / or removal of an external charger and the voltage of the external charger. Figure 1 As shown, the external charger includes a negative terminal P- and a positive terminal P+, and the battery module includes a positive terminal B+ and a negative terminal B-. A charging switch and a discharging switch are provided between the negative terminals P- and B-, and a fuse is provided between the positive terminals P+ and B+.

[0038] Furthermore, the battery management system includes a battery sampling chip (AFE (Analog Front End) in the diagram) and a microcontroller unit. In one specific implementation, the battery management system can be represented by a circuit board.

[0039] In one embodiment of this application, a charger detection circuit (e.g., ...) is provided between the microcontroller unit and the negative terminal P-. Figure 1As shown, the charger detection circuit can detect the insertion and removal of the charger. When the charger detection circuit detects that the charger is inserted, the microcontroller can control the charging switch to close, so that the external charger can charge the battery module; when the charger detection circuit detects that the charger is removed, the microcontroller can control the charging switch to open, so as to end the charging of the battery module.

[0040] In another embodiment of this application, the inventors noted that when the external charger is an illegitimate charger, its rated charging voltage may be excessively higher than the rated voltage of the battery module. Using a charger whose voltage is incompatible with the battery module's rated voltage will affect the battery module's performance and lifespan. It is understood that when the rated charging voltage of the external charger does not match the rated voltage of the battery module, the external charger can be considered an illegitimate charger. For example, if the rated voltage of the battery module is 48V and the rated charging voltage of the external charger is 60V, this charger is considered an illegitimate charger. Based on this, the inventors designed a charging detection circuit and a charger voltage detection circuit in the battery management system to detect the insertion or removal of the charger and to detect the voltage of the external charger. The battery management system can control the charging of the external charger based on the detected voltage. When it detects that the rated charging voltage of the external charger does not match the rated voltage of the battery module, it determines that the external charger is an illegitimate charger. At this time, it can control the charging switch to remain open to prevent the use of an illegitimate charger to charge the battery module.

[0041] Furthermore, this voltage detection circuit utilizes the "virtual short" and "virtual open" characteristics of the operational amplifier to detect the voltage of the external charger. The detection principle is simple, the detection circuit structure is simple, and it can achieve simple, effective, and accurate detection of the voltage of the external charger.

[0042] Please refer to the reference. Figures 2-13 The diagram below is a schematic diagram of the structure of the battery management system 10 provided in the embodiment of this application. The battery management system 10 includes: a microcontroller unit 11, a voltage detection circuit 12, a first voltage source 13, and a second voltage source 14.

[0043] The microcontroller unit 11 is configured to be electrically connected to the battery module for acquiring the voltage of the battery module. In one specific implementation, the microcontroller unit 11 can be a microcontroller chip.

[0044] In some embodiments, the microcontroller unit 11 is configured to be electrically connected to the battery module via an AFE (Automatic External Frame). The AFE, within the battery management system 10, can be a battery sampling chip capable of acquiring cell voltage and temperature. Therefore, the voltage of the battery module can be acquired via the AFE, and the microcontroller unit 11 can obtain the acquired battery module voltage from the AFE. In other embodiments, the microcontroller unit 11 can be directly electrically connected to the battery module to acquire cell voltage and temperature.

[0045] The voltage detection circuit 12 is used to detect the voltage of the external charger and includes: operational amplifier U1, first resistor R1 and second resistor R2.

[0046] The first voltage source 13 is electrically connected to the operational amplifier U1 to supply power to the operational amplifier U1; the second voltage source 14 is electrically connected to the first input terminal of the operational amplifier U1 to provide a reference voltage to the operational amplifier U1; and the output terminal of the operational amplifier U1 is electrically connected to the microcontroller unit 11.

[0047] The first end of the first resistor R1 is electrically connected to the second input terminal of the operational amplifier U1, and the second end of the first resistor R1 is used to be electrically connected to the negative terminal of the external charger and the negative terminal of the battery module, respectively.

[0048] The second resistor R2 is electrically connected between the second input terminal and the output terminal of the operational amplifier U1.

[0049] In some embodiments, operational amplifier U1 includes: a non-inverting input terminal, an inverting input terminal, a first power supply terminal, a second power supply terminal, and an output terminal. It is understood that the first input terminal can be a non-inverting input terminal, the second input terminal can be an inverting input terminal, and the output terminal is the output terminal. The first voltage source 13 can be electrically connected to the first power supply terminal, and the second power supply terminal can be grounded.

[0050] In some embodiments, when an external charger is connected, the voltage of the external charger is higher than the voltage of the battery module. This results in a voltage difference between the negative terminals P- and B-, i.e., V. B- -V P- =V 充电器 -V 电池 Among them, V 充电器 For the charger voltage that needs to be determined, V 电池 V is the voltage of the battery module obtained by the microcontroller unit 11. B- The voltage at the negative terminal B-, V P- The voltage at the negative terminal P-.

[0051] Let the output voltage of the first voltage source 13 be V1, the voltage of the second voltage source 14 be V3, and the voltage at the second input terminal of the operational amplifier U1 be V4. Based on the "virtual short" characteristic of the input of the operational amplifier U1, V3 = V4. Here, "virtual short" means that under ideal conditions, the potentials of the two input terminals are equal, which can be understood as the two input terminals being shorted together, but in reality they are not shorted.

[0052] Setting the output voltage of operational amplifier U1 to V5, based on the "virtual open" characteristic of operational amplifier U1's input, we can obtain: (V4 - V5) / V5 = 5 / 5. p- R1 = (V5 - V4) / R2. Here, "virtual open circuit" means that, under ideal conditions, the current flowing into the input terminal of operational amplifier U1 is zero.

[0053] Furthermore, the battery module can use the negative terminal B- as the reference ground, then V B- =0V.

[0054] Therefore, in R1, R2, V3, V5, and V 电池 Given that everything is known, based on: V B- -V P- =V 充电器 -V 电池 V3 = V4, (V4 - V p- ) / R1=(V5-V4) / R2、V B- =0V, so V can be determined. 充电器 =V 电池 +R1(V5-V3) / R2-V3.

[0055] Therefore, the battery management system 10 can detect the voltage of the external charger through the voltage detection circuit 12.

[0056] In this embodiment, the accuracy of the resistors (including the first resistor R1 and the second resistor R2, as well as the various resistors described in subsequent embodiments) can be 1%, and the accuracy of the first voltage source 13 and the second voltage source 14 can be ±100mV. Furthermore, the microcontroller unit 11 can use a 12-bit ADC (Analog-to-digital converter) for voltage sampling to achieve a charger voltage acquisition accuracy of ±1%. In some embodiments, using higher-precision resistors and voltage sources can achieve even higher-precision charger voltage sampling.

[0057] In some embodiments, the first voltage source 13 is a voltage source that provides a reference voltage to power the battery management system 10 and the operational amplifier U1. The output voltage V1 of this voltage source can be 3.3V or 5V, and can be an internal voltage source or an external voltage source.

[0058] In some embodiments, the second voltage source 14 includes a voltage source that provides a reference voltage. In this embodiment, the second voltage source 14 can be understood as a reference voltage source, similar to the first voltage source 13, and can be an internal voltage source or an external voltage source. The output power of the second voltage source 14 can be used as the input voltage of the first input terminal of the operational amplifier. In one specific implementation of this application, the range of this input voltage is 0-V1.

[0059] In other embodiments, the second voltage source 14 can be a voltage obtained by dividing the first voltage source 13. Please refer to... Figure 3 The voltage detection circuit 12 also includes a voltage divider branch 15, which is electrically connected between the first voltage source 13 and ground. The voltage divider branch 15 includes at least two resistors connected in series, and the node between the series resistors is electrically connected to the first input terminal of the operational amplifier U1.

[0060] The voltage of the second voltage source 14 can be adjusted by regulating the values ​​of at least two resistors connected in series.

[0061] Based on the aforementioned calculation principle of the charger voltage, when the second voltage source 14 is a voltage obtained through voltage division, the aforementioned V3 needs to be determined through V1.

[0062] Assuming that voltage divider branch 15 includes two resistors RA and RB connected in series, then V3 = V1 / (RA+RB)×RA. Correspondingly, in the aforementioned formula for calculating the charger voltage, given that RA, RB, and V1 are known, replacing V3 with V1 / (RA+RB)×RA will allow the charger voltage to be calculated.

[0063] In the technical solution of this application embodiment, the second voltage source 14 can be a voltage source that provides a reference voltage. In one specific implementation, the second voltage source 14 can be a chip that can stably output a reference voltage, such as a voltage conversion chip, voltage converter, etc.; or it can be a voltage source after dividing the first voltage source 13; to realize the effective voltage input of the first input terminal.

[0064] In some embodiments, please refer to Figure 4 The battery management system 10 also includes a charger detection circuit 16. The charger detection circuit 16 is electrically connected to the negative terminal P- of an external charger, and is also electrically connected to a first voltage source 13, a microcontroller unit 11, and ground. The microcontroller unit 11 is configured to acquire the electrical signal output by the charger detection circuit 16 to determine the electrical connection status between the external charger and the battery module.

[0065] It is understood that when the charger is plugged in, the negative terminal P- of the charger is electrically connected to the charger detection circuit 16, and the electrical signal detected by the charger detection circuit 16 will change compared to when the charger is not plugged in. Therefore, by acquiring the electrical signal output by the charger detection circuit 16, the microcontroller unit 11 can determine the electrical connection status between the external charger and the battery module, thereby determining whether the external charger is plugged in or removed.

[0066] In the technical solution of this application embodiment, the charger detection circuit 16 detects whether an external charger is inserted, so that the first voltage source 13 supplies power to the operational amplifier U1 according to the insertion detection result. That is, voltage detection only begins after the charger is detected to be inserted. In this way, invalid detection when the charger is not inserted is avoided, reducing the power consumption of the system.

[0067] In some embodiments, please refer to Figure 5 The charger detection circuit 16 includes a first switch 160 and a second switch 162. The first switch 160 is electrically connected to the second switch 162 and ground, and is also used to electrically connect to the negative terminal of an external charger. The second switch 162 is electrically connected to the first voltage source 13 and the microcontroller unit 11, and the second switch 162 can switch on and off in response to the on / off state of the first switch 160.

[0068] In some embodiments, both the first switch 160 and the second switch 162 can be transistors.

[0069] Please see Figure 6 In one specific implementation, the first switch 160 is an NPN transistor, and the second switch 162 is a PNP transistor. The emitter of the first switch 160 is electrically connected to the negative terminal of an external charger, the base of the first switch 160 is electrically connected to ground, and the collector of the first switch 160 is electrically connected to the second switch 162. The base of the second switch 162 is electrically connected to the collector of the first switch 160, the emitter of the second switch 162 is electrically connected to the first voltage source 13, and the collector of the second switch 162 is electrically connected to the microcontroller unit 11.

[0070] In other embodiments, the first switch 160 and the second switch 162 may be other switching devices, such as field-effect transistors. The switching type of the first switch 160 and the second switch 162 is not specifically limited in this embodiment.

[0071] In some embodiments, when the voltage difference between the negative terminal P- and the negative battery terminal B- is greater than the turn-on voltage of the first switch 160, the first switch 160 is saturated and turned on (e.g., when the voltage difference between the negative terminal P- and the negative battery terminal B- is greater than the turn-on voltage between the base and emitter of the first switch 160, the first switch 160 can be turned on), thereby causing the second switch 162 to be saturated and turned on. The charging detection circuit 16 can detect that the charger is inserted, and the output signal changes, for example, from low level to high level. The microcontroller unit 11 can receive the signal sent by the charging detection circuit and thus determine that the charger is inserted.

[0072] Please refer to Figure 7 The charger detection circuit 16 also includes a first diode D1, wherein the negative terminal of the first diode D1 is electrically connected to the negative terminal of the external charger, and the positive terminal of the first diode D1 is electrically connected to the first switch 160.

[0073] The first diode D1 is connected between the negative terminal of the external charger and the first switch 160. It can be called a reverse protection diode, which prevents reverse voltage and overvoltage, thereby ensuring the safety of the charging detection circuit.

[0074] In some embodiments, the first diode D1 can be replaced by other devices that can achieve the anti-reverse function, and this application does not limit the implementation of the anti-reverse function.

[0075] Please refer to Figure 8 The charger detection circuit 16 also includes: a third resistor R3, a fourth resistor R4, a fifth resistor R5, and a sixth resistor R6.

[0076] The third resistor R3 is electrically connected between the first switch 160 and the second switch 162; the fourth resistor R4 is electrically connected between the control terminal of the second switch 162 and the first terminal of the second switch 162; the fifth resistor R5 is electrically connected between the control terminal of the first switch 160 and the first terminal of the first switch 160; and the sixth resistor R6 is electrically connected between the control terminal of the first switch 160 and ground.

[0077] It is understood that if the first switch 160 and the second switch 162 adopt the aforementioned transistor implementation method, the control terminal of the first switch 160 is the base, the control terminal of the second switch 162 is also the base, the first terminal of the first switch 160 is the emitter, and the first terminal of the second switch 162 is also the emitter.

[0078] The third resistor R3, the fourth resistor R4, the fifth resistor R5, and the sixth resistor R6 are set at the corresponding terminals of the switches to limit current and match impedance, thereby ensuring the safety of the first switch 160 and the second switch 162, as well as the safety of the entire circuit.

[0079] In some embodiments, the third resistor R3, the fourth resistor R4, the fifth resistor R5, and the sixth resistor R6 described above may be replaced by other devices that can achieve current limiting and impedance matching, and this is not limited in the embodiments of this application.

[0080] In some embodiments, please refer to Figure 9 The charger detection circuit 16 also includes: a seventh resistor R7, an eighth resistor R8, and a first capacitor C1.

[0081] Among them, the seventh resistor R7 is electrically connected between the second terminal of the second switch 162 and ground; the eighth resistor R8 and the first capacitor C1 are connected in series between the second terminal of the second switch 162 and ground, and the eighth resistor R8 is also electrically connected to the microcontroller unit 11.

[0082] Based on the aforementioned description of the implementation of the second switch 162, if the second switch 162 is a transistor, the second terminal of the second switch 162 corresponds to the collector of the transistor.

[0083] In this implementation, the seventh resistor R7 can act as a pull-down resistor to stabilize the voltage, while the eighth resistor R8 and the first capacitor C1 act as filters. That is, the seventh resistor R7, the eighth resistor R8, and the first capacitor C1 together form a filter circuit to filter the signal and improve the accuracy of the detection results.

[0084] In some embodiments, depending on the specific application scenario, more capacitors or resistors can be set to achieve a filtering effect. That is, the structure of the filtering circuit is not limited to this and is not limited in the embodiments of this application.

[0085] In some embodiments, please refer to Figure 10 The voltage detection circuit 12 also includes an anti-static diode and a transient diode D0, which are connected to the first resistor R1 and ground respectively.

[0086] The transient diode D0 can serve as an anti-static device, providing a discharge circuit for external static electricity. It is electrically connected between the first resistor R1 and ground, so that when static electricity occurs in the voltage detection circuit 12, it can discharge the static electricity through the transient diode D0.

[0087] In some embodiments, please refer to Figure 11 The voltage detection circuit 12 also includes a second diode D2. The second diode D2 is electrically connected between the second input terminal of the operational amplifier U1 and ground.

[0088] In some embodiments, the second diode D2 can be a Schottky diode, which can bypass the operational amplifier U1 when a negative voltage appears at the negative terminal P-. The current flows through the second diode D2 and the first resistor R1 to the negative terminal P-, thus protecting the operational amplifier U1.

[0089] It is understood that the aforementioned diodes can be replaced by other devices that perform the corresponding functions, and this is not limited here.

[0090] In some embodiments, please refer to Figure 12 The voltage detection circuit 12 also includes a second capacitor C2. The second capacitor C2 is electrically connected between the second input terminal and the output terminal of the operational amplifier U1.

[0091] In this implementation, the second capacitor C2 can act as a filter. Furthermore, since it is electrically connected between the second input terminal and the output terminal of operational amplifier U1, it can also filter out transient voltages.

[0092] In some embodiments, please refer to Figure 13 The voltage detection circuit 12 also includes a ninth resistor R9 and a third capacitor C3. The ninth resistor R9 and the third capacitor C3 are connected in series between the output terminal of the operational amplifier U1 and ground, and the node between the ninth resistor R9 and the third capacitor C3 is electrically connected to the microcontroller unit 11.

[0093] In this implementation, the ninth resistor R9 and the third capacitor C3 constitute a filter circuit to filter the nodes between the output of the operational amplifier U1 and the microcontroller unit 11, thereby improving the accuracy of the detection results.

[0094] The node between the ninth resistor R9 and the third capacitor C3 can be any other device in the voltage detection circuit 12, or a connection node, etc., and is not limited here.

[0095] In some embodiments, in addition to the ninth resistor R9 and the third capacitor C3, more resistors, capacitors or other filtering devices can be used to form a more layered filtering circuit. That is, the structure of the filtering circuit can be implemented in more ways, which are not limited here.

[0096] Based on the foregoing embodiments, the microcontroller unit 11 of the battery management system 10 can implement charger voltage detection in two optional ways.

[0097] In the first optional implementation, the charger detection circuit 16 is not included. The first voltage source 13 and the second voltage source 14 continuously supply power to the operational amplifier U1. In this case, the operational amplifier U1 will continuously detect the charger voltage regardless of whether the charger is plugged in. Correspondingly, if the charger is not plugged in, the corresponding detection value may be 0.

[0098] In this implementation, the voltage detection circuit 12 operates continuously, resulting in higher system power consumption, but the circuit structure is simpler.

[0099] In a second optional implementation, a charger detection circuit 16 is provided, and the first voltage source 13 and the second voltage source 14 are controlled by the microcontroller unit 11. When the microcontroller unit 11 determines that the charger is inserted based on the electrical signal output by the charger detection circuit 16, it then controls the first voltage source 13 and the second voltage source 14 to supply power to the operational amplifier U1, and the operational amplifier U1 will then begin to detect the charger voltage.

[0100] In this embodiment, the voltage detection circuit 12 does not run continuously, resulting in lower system power consumption. However, the circuit structure includes an additional charger detection circuit compared to the first optional embodiment.

[0101] Therefore, the two implementation methods described above can be flexibly selected based on the specific application scenario.

[0102] Please refer to Figure 14 This is a schematic diagram of the circuit structure of a battery management system 10 used in an application scenario. This circuit structure includes most of the devices described in the above embodiments, and can realize accurate, stable, safe and low-power charger voltage detection.

[0103] Please refer to Figure 15 This is a schematic diagram of a battery pack 20 provided in an embodiment of this application. The battery pack 20 includes a battery module 21 and a battery management system 10, wherein the battery module 21 includes at least one battery cell.

[0104] The battery module 21 is electrically connected to the battery management system 10. The battery module 21 can discharge to the outside world and can also be charged through the battery management system 10.

[0105] Please refer to Figure 16 This application also provides an electrical device 30, including a battery pack 20.

[0106] It should be understood that the power-consuming device 30 provided in this application embodiment uses a battery module 21 as its power source. The power-consuming device 30 can be, but is not limited to, mobile phones, tablets, laptops, electric toys, power tools, drones, electric two-wheelers (such as electric vehicles, electric bicycles, etc.), electric motorcycles, electric tricycles, electric cars, ships, spacecraft, etc. Among these, electric toys can include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc., and spacecraft can include airplanes, rockets, space shuttles, and spacecraft, etc.

[0107] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and not to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application, and they should all be covered within the scope of the claims and specification of this application. In particular, as long as there is no structural or step conflict, the various technical features mentioned in the various embodiments can be combined in any way. This application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A battery management system, comprising a microcontroller unit configured to be electrically connected to a battery module for acquiring the voltage of the battery module, characterized in that, It also includes a voltage detection circuit, a first voltage source, and a second voltage source, wherein the voltage detection circuit is used to detect the voltage of the external charger; The voltage detection circuit includes an operational amplifier, a first voltage source electrically connected to the operational amplifier for supplying power to the operational amplifier, a second voltage source electrically connected to a first input terminal of the operational amplifier for providing a reference voltage to the operational amplifier, and an output terminal of the operational amplifier electrically connected to the microcontroller unit. The voltage detection circuit further includes a first resistor and a second resistor. The first end of the first resistor is electrically connected to the second input terminal of the operational amplifier. The second end of the first resistor is used to connect to the negative terminal of an external charger. The second end of the first resistor is also electrically connected to the negative terminal of the battery module through a charging switch and a discharging switch. The charging switch and the discharging switch are connected in series between the negative terminal and the negative terminal of the battery module. The second resistor is electrically connected between the second input terminal and the output terminal of the operational amplifier.

2. The battery management system according to claim 1, characterized in that, The second voltage source includes a voltage source that provides a reference voltage; or, The voltage detection circuit further includes a voltage divider branch electrically connected between the first voltage source and ground. The voltage divider branch includes at least two resistors connected in series, and the node between the series resistors is electrically connected to the first input terminal of the operational amplifier.

3. The battery management system according to claim 1 or 2, characterized in that, The battery management system further includes a charger detection circuit, which is electrically connected to the negative terminal of an external charger and is also electrically connected to the first voltage source, the microcontroller unit, and ground. The microcontroller unit is configured to acquire the electrical signal output by the charger detection circuit to determine the electrical connection status between the external charger and the battery module.

4. The battery management system according to claim 3, characterized in that, The charger detection circuit includes a first switch and a second switch; The second terminal and the control terminal of the first switch are electrically connected to the control terminal of the second switch and ground, respectively. The first terminal of the first switch is also used to be electrically connected to the negative terminal of an external charger. The first and second terminals of the second switch are electrically connected to the first voltage source and the microcontroller unit, respectively, and the second switch can switch on and off in accordance with the on and off states of the first switch.

5. The battery management system according to claim 4, characterized in that, The charger detection circuit further includes a first diode, wherein the negative terminal of the first diode is electrically connected to the negative terminal of the external charger, and the positive terminal of the first diode is electrically connected to the first terminal of the first switch.

6. The battery management system according to claim 4, characterized in that, The charger detection circuit also includes: a third resistor, a fourth resistor, a fifth resistor, and a sixth resistor; The third resistor is electrically connected between the second terminal of the first switch and the control terminal of the second switch; The fourth resistor is electrically connected between the control terminal of the second switch and the first terminal of the second switch; The fifth resistor is electrically connected between the control terminal of the first switch and the first terminal of the first switch; The sixth resistor is electrically connected between the control terminal of the first switch and ground.

7. The battery management system according to claim 4, characterized in that, The charger detection circuit also includes: a seventh resistor, an eighth resistor, and a first capacitor; The seventh resistor is electrically connected between the second terminal of the second switch and ground; The eighth resistor and the first capacitor are connected in series between the second terminal of the second switch and ground, and the eighth resistor is also electrically connected to the microcontroller unit.

8. The battery management system according to claim 1, characterized in that, The voltage detection circuit further includes a transient diode; the transient diode is connected to the first resistor and ground respectively.

9. The battery management system according to claim 1, characterized in that, The voltage detection circuit further includes a second diode, wherein the second diode is electrically connected between the second input terminal of the operational amplifier and ground.

10. The battery management system according to claim 1, characterized in that, The voltage detection circuit also includes a second capacitor; The second capacitor is electrically connected between the second input terminal and the output terminal of the operational amplifier.

11. The battery management system according to claim 1, characterized in that, The voltage detection circuit also includes a ninth resistor and a third capacitor; The ninth resistor and the third capacitor are connected in series between the output terminal of the operational amplifier and ground, and the node between the ninth resistor and the third capacitor is electrically connected to the microcontroller unit.

12. A battery pack, characterized in that, It includes a battery module and a battery management system as described in any one of claims 1-11, wherein the battery module includes at least one battery cell.

13. An electrical appliance, characterized in that, Includes the battery pack as described in claim 12.

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