Circuit for realizing asynchronous serial port communication, battery management system and electric energy system

Abstract

The utility model discloses a circuit for realizing asynchronous serial port communication, a battery management system and an electric energy system, and relates to the technical field of batteries, a control module controls a charging loop of a battery to be switched on or switched off through a first asynchronous serial port of the control module; the control module is electrically connected with the first end of the coding module through a second asynchronous serial port of the control module; the second end of the coding module is electrically connected with a current sampling unit in the charging loop; the first asynchronous serial port is configured to serve as a general input and output port when the battery is charged and serve as a data sending port after the battery is charged. According to the utility model, communication can be realized without additional operation and additional communication cables. Communication between the lithium batteries connected in series is achieved at the lowest cost, the whole circuit is simple, materials are conventional, implementation is easy, and the cost is relatively low. In addition, the UART function of the control module is sound, and serial port drive codes used on the project can be reused, so that the software design is simple, and the practicability is high.

Description

Technical Field

[0001] The utility model relates to the technical field of batteries, in particular to a circuit for realizing asynchronous serial communication, a battery management system and an electric energy system. Background Art

[0002] Before the emergence of lithium batteries, lead-acid batteries were widely used in various devices that require electrical energy to work. After the emergence of lithium batteries, due to their advantages in various aspects, they quickly replaced lead-acid batteries as the source of power for equipment.

[0003] Lithium batteries are currently widely used and have replaced lead-acid batteries. However, due to the performance limitations of lead-acid batteries, devices that use lead-acid batteries as power sources may need to be replaced with lithium batteries. Other parts of the device may also work well, but the lead-acid battery can no longer meet the power supply needs and needs to be replaced with lithium batteries.

[0004] However, due to the characteristics of lead-acid batteries, there is no need to set up communication lines, only two main circuit cables (usually positive and negative cables, used for lead-acid batteries to output current to the equipment), while lithium batteries must have a battery management system (BMS) due to their characteristics. Battery management systems need to communicate with each other to achieve various functions such as charging and discharging. Therefore, in the current application scenarios where lithium batteries replace lead-acid batteries, additional communication cables are needed to achieve communication between different battery management systems. This results in a complex structure of the entire power supply system, cumbersome control logic and high cost. Utility Model Content

[0005] In view of the above problems, the utility model provides a circuit, a battery management system and an electric energy system for realizing asynchronous serial communication, which better solve the above problems.

[0006] The embodiment of the utility model provides a circuit for realizing asynchronous serial communication, and the circuit is applied to a battery management system;

[0007] The circuit comprises: a control module and an encoding module;

[0008] The control module controls the charging circuit of the battery to be turned on or off through its own first asynchronous serial port;

[0009] The control module is electrically connected to the first end of the encoding module through its second asynchronous serial port;

[0010] The second end of the encoding module is electrically connected to the current sampling unit in the charging circuit, and the encoding module stores a preset code;

[0011] Wherein, the first asynchronous serial port is configured to control the charging circuit to be turned on or off according to the corresponding sequence of the preset codes when communication is required.

[0012] Optionally, the first asynchronous serial port is configured to control a charging circuit of the battery to be turned on when the battery is being charged.

[0013] Optionally, the encoding module is configured to send a target level to the second asynchronous serial port when the battery is charged;

[0014] The encoding module is configured to form a corresponding digital encoding sequence and send it to the second asynchronous serial port according to the on / off sequence of the charging circuit when communication is required;

[0015] The second asynchronous serial port is configured to receive the target level when the battery is charged and is in an idle state;

[0016] The second asynchronous serial port is configured to receive the digital code sequence when communication is required.

[0017] Optionally, the circuit further comprises: a driving unit;

[0018] The driving unit is arranged between the first asynchronous serial port and the charging circuit, and is used to amplify and enhance the signal sent by the first asynchronous serial port, so that the signal controls the charging circuit to be turned on or off.

[0019] Optionally, the encoding module includes: a voltage unit and a comparison unit;

[0020] The input end of the voltage unit is connected in parallel with the current sampling unit, and the output end thereof is electrically connected with the input end of the comparison unit;

[0021] The output end of the comparison unit is electrically connected to the second asynchronous serial port.

[0022] Optionally, the voltage unit obtains the real-time voltage of the charging circuit by using the current sampling unit, and sends the real-time voltage to the comparison unit;

[0023] The comparison unit compares the real-time voltage with a reference voltage, and generates the target level or the digital code sequence according to a comparison structure.

[0024] Optionally, the voltage unit includes: a differential amplifier, a first resistor, a second resistor, a third resistor, and a fourth resistor; the comparison unit includes: an in-phase comparator;

[0025] The positive input terminal of the differential amplifier is electrically connected to the second end of the first resistor and the first end of the second resistor respectively;

[0026] The second end of the second resistor is electrically connected to the current input end of the current sampling unit;

[0027] A first end of the first resistor is grounded;

[0028] The negative input terminal of the differential amplifier is electrically connected to the first end of the third resistor and the first end of the fourth resistor respectively;

[0029] The second end of the third resistor is electrically connected to the output end of the differential amplifier and the non-inverting end of the non-inverting comparator;

[0030] The second end of the fourth resistor is electrically connected to the current output end of the current sampling unit;

[0031] The inverting terminal of the non-inverting comparator receives a reference voltage;

[0032] The output end of the non-inverting comparator is electrically connected to the second asynchronous serial port.

[0033] Optionally, when the battery is charging, the control module is configured to use the first asynchronous serial port to control the charging circuit to be continuously turned on;

[0034] When communication is required, the control module is configured to first use the first asynchronous serial port to control the charging circuit to be turned off, and then configure the first asynchronous serial port as the data transmission port; or,

[0035] The control module is configured to first configure the first asynchronous serial port as the data transmission port, and then use the first asynchronous serial port to control the charging circuit to be turned off;

[0036] After the first asynchronous serial port is configured as the data transmission port, the control module is configured to send data bits according to the corresponding sequence of the preset code based on the first asynchronous serial port to control the charging circuit to be turned on or off.

[0037] Optionally, the voltage unit is configured so that when the battery is charged, the real-time voltage outputted by the voltage unit is always greater than the reference voltage;

[0038] The voltage unit is configured such that when communication is required, the real-time voltage outputted by the voltage unit is greater than the reference voltage when the charging circuit is turned on, and is less than the reference voltage when the charging circuit is turned off;

[0039] The comparison unit is configured to output a high level when the real-time voltage is greater than the reference voltage, and to output a low level when the real-time voltage is less than the reference voltage.

[0040] Optionally, the circuit further comprises: a charging bypass;

[0041] The charging bypass is connected to the input and output ports of the control module;

[0042] The charging bypass is configured to be in an off state when the battery is being charged, and to be in an on state after the battery is completely charged.

[0043] Optionally, the current sampling unit includes: a current sampling resistor;

[0044] The second end of the encoding module is connected across two ends of the current sampling resistor.

[0045] An embodiment of the utility model further provides a battery management system, which includes the circuit as described in any one of the above items.

[0046] The embodiment of the utility model further provides an electric energy system, which includes: a battery module and a battery management system, and the battery management system is the above-mentioned battery management system.

[0047] Optionally, the number of the battery modules and the number of the battery management systems are both multiple and correspond one to one, and the multiple battery modules are connected in series.

[0048] Optionally, it further includes a plurality of charging bypasses, and the charging bypasses are connected one-to-one with the plurality of battery modules. When the battery management system controls the charging circuit of the corresponding battery to be disconnected, the battery management system controls the charging bypass to be closed.

[0049] The circuit for realizing asynchronous serial communication proposed in the utility model does not require additional operation and the addition of communication cables. It directly uses the BMS's own control module in the two working states of charging and non-charging to configure the asynchronous serial port (Universal Asynchronous Receiver / Transmitter, abbreviated as UART) as different functional ports, uses the asynchronous serial port signal to control the on-off of the charging circuit to realize current coding, and combines with the coding module to convert the current coding into a digital coding sequence with a fixed level.

[0050] Since the signal for controlling the on and off directly uses the TX of the asynchronous serial port, the generated current encoding also conforms to the encoding specification of the asynchronous serial port, so that the communication of the BMS can be realized without additional operation and adding communication cables. The communication between the lithium batteries in series is realized at the lowest cost, and the entire circuit is streamlined, the materials are conventional, easy to implement and the cost is relatively low. In addition, since the UART function of the control module itself is sound, the serial port driver code used in the project can be reused, so the software design is simple and has high practicality. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] By reading the detailed description of the preferred embodiment below, various other advantages and benefits will become clear to those of ordinary skill in the art. The accompanying drawings are only used for the purpose of illustrating the preferred embodiment and are not considered to be limiting of the present invention. Moreover, the same reference symbols are used throughout the accompanying drawings to represent the same components. In the accompanying drawings:

[0052] Figure 1 It is a schematic diagram of a structure for bidirectional single-line data transmission of data information between a conventional electronic control unit 2 and at least one peripheral device 3;

[0053] Figure 2 This is a schematic diagram of a modular circuit for realizing asynchronous serial communication according to an embodiment of the utility model;

[0054] Figure 3 It is a structural schematic diagram of a circuit for realizing asynchronous serial communication, taking specific components as an example in an embodiment of the utility model. DETAILED DESCRIPTION

[0055] In order to make the above-mentioned purposes, features and advantages of the utility model more obvious and easy to understand, the utility model is further described in detail below in conjunction with the accompanying drawings and specific implementation methods. It should be understood that the specific embodiments described here are only used to explain the utility model, are only part of the embodiments of the utility model, not all of the embodiments, and are not used to limit the utility model.

[0056] The inventors have found that in the current application scenarios where lithium batteries replace lead-acid batteries, additional operations and additional communication cables are required, which results in a complex structure of the entire power supply system, cumbersome control logic and high cost.

[0057] For example, refer to Figure 1 The structural schematic diagram of bidirectional single-line data transmission of data information between the electronic control unit 2 and at least one peripheral device 3 shown in the figure requires a predetermined constant voltage or a predetermined constant current to be applied to the drive device 20 of the electronic control unit 2 in order to generate voltage-coded or current-coded information.

[0058] The voltage-coded or current-coded information is then transmitted from the drive device 20 of the electronic control unit 2 to the drive device 30 of the peripheral device 3 via the single-wire line 4; at least the drive logic circuit of the drive device 30 and / or the communication logic circuit of the peripheral device 3 are controlled and powered by the current.

[0059] The information present at the peripheral device 3 by controlling the peripheral device is current- or voltage-coded; during the control of the peripheral device 3 , the current- or voltage-coded information is transmitted back from the drive 30 of the peripheral device 3 to the drive 20 of the electronic control unit 2 via the same single-wire line 4 .

[0060] Although the above structure realizes single-line communication, it also needs to add a communication line to realize the communication carrier. At the same time, the encoding of the current requires an additional drive device to be transmitted to the electronic control unit. And it is also necessary to predetermine a constant voltage or current. These conditions are indispensable. Obviously, these additional operations and added communication cables have led to a complex structure of the entire power supply system, cumbersome control logic and high cost.

[0061] In view of the above problems, the inventor has creatively proposed the circuit of realizing asynchronous serial communication of the utility model after in-depth research, which has better solved the above problems. The scheme of the utility model is specifically explained and illustrated below.

[0062] The circuit for realizing asynchronous serial communication proposed in the utility model is applied to the battery management system, especially to the scenario where a battery with a communication line replaces a battery without a communication line. For example, a lithium battery is a battery with a communication line, while a lead-acid battery is a battery without a communication line.

[0063] Reference Figure 2 The modular schematic diagram shown in the figure shows that the circuit for realizing asynchronous serial communication includes: a control module and an encoding module. The control module controls the charging circuit of the battery to be turned on or off through its own first asynchronous serial port; the control module is electrically connected to the first end of the encoding module through its own second asynchronous serial port; the second end of the encoding module is electrically connected to the current sampling unit in the charging circuit, and the encoding module stores a preset code. Among them, the first asynchronous serial port is configured to control the charging circuit to be turned on or off according to the corresponding sequence of the preset code when communication is required.

[0064] It should be noted that Figure 2 The communication signal sent by the first asynchronous serial port can control the charging circuit of the battery to be turned on or off, which is exemplified in the form of a switch. It does not represent a specific circuit structure, and any components, integrated circuits or complex circuit structures that can realize the communication signal to control the charging circuit to be turned on or off are acceptable.

[0065] Based on the above circuit structure, the control module is configured to configure the first asynchronous serial port as a general input / output port (i.e., Input / Output, generally referred to as IO port) when the battery is charged, and use the first asynchronous serial port to control the conduction of the battery charging circuit. Since communication is not required during battery charging, the first asynchronous serial port does not need to send communication signals, and the second asynchronous serial port does not need to receive communication signals. Therefore, when the battery is charged, the first asynchronous serial port can be configured as a general IO port.

[0066] The control module is configured to configure the first asynchronous serial port as a data transmission port when communication is required (generally, communication is required only after the battery is charged), and use the first asynchronous serial port to control the charging circuit to be turned on or off in a corresponding order of a preset code; since communication is required after the battery is charged, the first asynchronous serial port needs to send a communication signal, and the second asynchronous serial port also needs to receive a communication signal, so after the battery is charged, the first asynchronous serial port can be configured as a data transmission port.

[0067] As for the encoding module, it is configured to send a target level to the second asynchronous serial port when the battery is charging; when communication is required, a corresponding digital coding sequence is formed according to the on-off sequence of the charging circuit and sent to the second asynchronous serial port; the second asynchronous serial port is configured to be in an idle state when the battery is charging; when communication is required, the digital coding sequence is received.

[0068] The purpose of sending the target level is to make the second asynchronous serial port idle. This is determined by the characteristics of the UART itself. For example: Under normal circumstances, the UART data receiving port will not feed back to other components of the control module even if it receives data without starting the enable data bit. Take 8 bits as a byte as an example: set the corresponding data bit of the charging circuit to 1, the corresponding data bit of the shutdown to 0, and the start enable data bit to 0. If the receiving port always receives data bit 1, then the receiving port is in an idle state. Only when it receives data bit 0, it starts working, and then the data bits after data bit 0 are digital codes; when it receives 8 digital codes (that is, 8 high or low data bits), for example, the 8 digital codes are 10101010, and the 9th data bit is the end enable data bit of the receiving port. Assuming that the end enable data bit is 0, the level corresponding to receiving a byte is 0101010100, and the digital code reception is completed.

[0069] Considering that the on-off control of some charging circuits requires a certain current driving capability, for example, in an application scenario where a field effect transistor (Metal-Oxide-Semiconductor Field-Effect Transistor, MOSFET, generally referred to as MOS tube) is used as a charging circuit switch, the on or off of the MOS tube requires that its gate terminal has a certain current driving capability, and the first asynchronous serial port sends a communication signal, and the current driving capability of the communication signal is relatively weak, which may not meet the current driving capability of the on or off of the MOS tube. Therefore, the entire circuit may also need to include: a driving unit; the driving unit is arranged between the first asynchronous serial port and the charging circuit, and is used to amplify and enhance the signal sent by the first asynchronous serial port, so that the signal controls the on or off of the charging circuit.

[0070] The encoding module implements sending a digital coding sequence to the second asynchronous serial port after charging is completed. A preferred structure of the encoding module includes: a voltage unit and a comparison unit. The input end of the voltage unit is connected in parallel with the current sampling unit, and its output end is electrically connected to the input end of the comparison unit; the output end of the comparison unit is electrically connected to the second asynchronous serial port. The voltage unit uses the current sampling unit to obtain the real-time voltage of the charging circuit, and sends the real-time voltage to the comparison unit; the comparison unit compares the real-time voltage with the reference voltage, and generates a target level or a digital coding sequence according to the comparison structure. For example: the reference voltage is set to a voltage value slightly lower than the actual effective current when the charging circuit is turned on. Then, when the real-time voltage is higher than the reference voltage, it indicates that the charging circuit is turned on, and the data bit is 1. When the real-time voltage is lower than the reference voltage, it indicates that the charging circuit is turned off, and the data bit is 0. The digital coding sequence is obtained in this way.

[0071] Those skilled in the art should understand that any component, integrated circuit or complex circuit structure that can realize the functions of the above voltage unit and comparison unit can constitute the encoding module. Figure 3 Explanations and illustrations are given using specific components as examples. Figure 3 This is a circuit structure of two batteries connected in series. For more circuit structures of batteries connected in series, refer to Figure 3 It can be obtained through simple reasoning.

[0072] Figure 3 In the figure, MCU represents the control module, TXD represents the first asynchronous serial port, RXD represents the second asynchronous serial port, PACK+ and PACK- represent the positive and negative poles of the battery respectively, and IO port represents the control output signal port of the control module MCU, which controls the on or off of the charging bypass CB. The charging bypass CB is connected to the input and output port IO port of the control module MCU; the charging bypass CB is configured to be in the off state when the battery is charged, and in the on state after the battery is fully charged.

[0073] Generally, a charger CG is used to charge the battery. When one battery is fully charged, it is necessary to switch to charging bypass to allow the remaining batteries that are not fully charged to continue charging.

[0074] The first asynchronous serial port TXD of the control module MUC is connected to one end of the MOS tube driver DV, and the other end of the MOS tube driver DV is connected to the gate end of the charging MOS tube CEFT. The MOS tube driver DV is used to amplify and enhance the communication signal sent by the first asynchronous serial port TXD to control the charging MOS tube CEFT to turn on or off. DEFT is a discharge MOS tube, which is generally available in battery BMS.

[0075] Reference Figure 3As shown, the voltage unit includes: a differential amplifier DAP, a first resistor R1, a second resistor R2, a third resistor R3, and a fourth resistor R4; the comparison unit includes: an in-phase comparator IPC. In addition, Figure 3 In the example, the current sampling unit is represented by a current sampling resistor RC.

[0076] The positive input terminal of the differential amplifier DAP is electrically connected to the second end of the first resistor R1 and the first end of the second resistor R2 respectively; the second end of the second resistor R2 is electrically connected to the current input end of the current sampling resistor RC; the first end of the first resistor R1 is grounded.

[0077] The negative input terminal of the differential amplifier DAP is electrically connected to the first end of the third resistor R3 and the first end of the fourth resistor R4 respectively; the second end of the third resistor R3 is electrically connected to the output terminal of the differential amplifier DAP and the in-phase terminal of the in-phase comparator IPC.

[0078] The second end of the fourth resistor R4 is electrically connected to the current output end of the current sampling resistor RC; the inverting end of the non-inverting comparator IPC receives the reference voltage Vref; and the output end of the non-inverting comparator IPC is electrically connected to the second asynchronous serial port RXD.

[0079] During the whole circuit operation, if the battery is charged, the control module MCU uses the first asynchronous serial port TXD to send a communication signal to control the charging MOS tube CEFT to be turned on, and the charging circuit of the battery is continuously turned on. The real-time current flowing through the charging circuit is differentially amplified by the differential amplifier DAP to obtain a real-time voltage corresponding to the real-time current. The real-time voltage is compared with the reference voltage Vref by the in-phase comparator IPC and the data bit 1 is output. Since the real-time current always flows through the charging circuit during charging, the real-time voltage is always greater than the reference voltage Vref, and the in-phase comparator IPC always outputs the data bit 1, and the second asynchronous serial port RDX is in an idle state.

[0080] When communication is needed, the control module MCU first uses the first asynchronous serial port TXD to control the charging MOS tube CEFT to turn off, then the charging circuit is turned off, and then the first asynchronous serial port TXD is configured as a data sending port; or the first asynchronous serial port TXD can be configured as a data sending port first, and then the first asynchronous serial port TXD is used to control the charging MOS tube CEFT to turn off.

[0081] After the first asynchronous serial port TXD is configured as the data sending port, the control module MCU uses the first asynchronous serial port TXD to send data bits 1 and 0 in the corresponding order of the preset code to control the charging MOS tube CEFT to be turned on and off in sequence, thereby turning on or off the charging circuit in sequence, wherein when the data bit is 1, the charging circuit is turned on, and when the data bit is 0, the charging circuit is turned off.

[0082] From the above description, it can be known that when the control module MCU first uses the first asynchronous serial port TXD to control the charging MOS tube CEFT to turn off for the first time so that the charging circuit is turned off, there is no real-time current flowing through the charging circuit, then the real-time voltage corresponding to the real-time current obtained after differential amplification by the differential amplifier DAP is 0, and the real-time voltage is definitely lower than the reference voltage Vref. After comparison by the in-phase comparator IPC, the data bit 0 is output, and the second asynchronous serial port RDX receives the start enable data bit 0, exits the idle state, and prepares to receive digital code.

[0083] After the first asynchronous serial port TXD is configured as a data transmission port, the control module MCU uses the first asynchronous serial port TXD to control the charging MOS tube CEFT to be turned on and off continuously according to the coding requirements. When it is turned on, the same direction comparator IPC sends data bit 1, and when it is turned off, the same direction comparator IPC sends data bit 0. In this way, the second asynchronous serial port RDX receives the digital code 10101010 in sequence. After the transmission of 8 data bits is completed, the control module MCU uses the first asynchronous serial port TXD to control the charging MOS tube CEFT to no longer be turned on, but always turned off, then the same direction comparator IPC sends data bit 0, the second asynchronous serial port RDX receives the end data 0, the data reception ends, and the reception of a byte of digital coding is completed. In this way, coding transmission and reception are realized. And because the real-time current used for coding flows in the main circuit, that is, the charging circuit, no matter how many batteries are connected in series, the control module MCU of each battery can synchronously use its own second asynchronous serial port RDX to receive the coding information, so that the communication between the BMSs of multiple batteries is realized.

[0084] Based on the above circuit for implementing asynchronous serial communication, an embodiment of the utility model further proposes a battery management system, which includes the circuit as described in any one of the above items.

[0085] Based on the above circuit for realizing asynchronous serial communication, an embodiment of the utility model further proposes an electric energy system, which includes: a battery module and a battery management system, and the battery management system is the aforementioned battery management system.

[0086] Optionally, the number of the battery modules and the number of the battery management systems are both multiple and correspond one to one, and the multiple battery modules are connected in series.

[0087] Optionally, the electric energy system further includes a plurality of charging bypasses and the charging bypasses are connected one-to-one with the plurality of battery modules. When the battery management system controls the charging circuit of the corresponding battery to be disconnected, the battery management system controls the charging bypass to be closed.

[0088] Through the above embodiments, the circuit for realizing asynchronous serial communication proposed by the utility model does not require additional operation and the addition of communication cables. The BMS control module itself is directly used to configure the asynchronous serial port (Universal Asynchronous Receiver / Transmitter, abbreviated as UART) as different functional ports in the two working states of charging and non-charging. The asynchronous serial port signal is used to control the on and off of the charging circuit to realize current coding, and the current coding is converted into a digital coding sequence of a fixed level in combination with the coding module.

[0089] Since the signal for controlling the on and off directly uses the TX of the asynchronous serial port, the generated current encoding also conforms to the encoding specification of the asynchronous serial port, so that the communication of the BMS can be realized without additional operation and adding communication cables. The communication between the lithium batteries in series is realized at the lowest cost, and the entire circuit is streamlined, the materials are conventional, easy to implement and the cost is relatively low. In addition, since the UART function of the control module itself is sound, the serial port driver code used in the project can be reused, so the software design is simple and has high practicality.

[0090] Although the preferred embodiments of the utility model embodiments have been described, those skilled in the art may make additional changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the utility model embodiments.

[0091] Finally, it should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or terminal device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or terminal device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or terminal device including the elements.

[0092] The embodiments of the present invention are described above in conjunction with the accompanying drawings and introduced in detail. Specific examples are used herein to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as a limitation on the present invention.

Claims

1. A circuit for realizing asynchronous serial communication, characterized in that: The circuit is applied to a battery management system; The circuit comprises: a control module and an encoding module; The control module controls the charging circuit of the battery to be turned on or off through its own first asynchronous serial port; The control module is electrically connected to the first end of the encoding module through its second asynchronous serial port; The second end of the encoding module is electrically connected to the current sampling unit in the charging circuit, and the encoding module stores a preset code; Wherein, the first asynchronous serial port is configured to control the charging circuit to be turned on or off according to the corresponding sequence of the preset codes when communication is required.

2. The circuit according to claim 1, characterized in that The first asynchronous serial port is configured to control the charging circuit of the battery to be turned on when the battery is charged.

3. The circuit according to claim 1, characterized in that The encoding module is configured to send a target level to the second asynchronous serial port when the battery is charged; The encoding module is configured to form a corresponding digital encoding sequence and send it to the second asynchronous serial port according to the on / off sequence of the charging circuit when communication is required; The second asynchronous serial port is configured to receive the target level when the battery is charged and is in an idle state; The second asynchronous serial port is configured to receive the digital code sequence when communication is required.

4. The circuit according to claim 1, characterized in that The circuit further comprises: a driving unit; The driving unit is arranged between the first asynchronous serial port and the charging circuit, and is used to amplify and enhance the signal sent by the first asynchronous serial port, so that the signal controls the charging circuit to be turned on or off.

5. The circuit according to claim 3, characterized in that The encoding module includes: a voltage unit and a comparison unit; The input end of the voltage unit is connected in parallel with the current sampling unit, and the output end thereof is electrically connected with the input end of the comparison unit; The output end of the comparison unit is electrically connected to the second asynchronous serial port.

6. The circuit according to claim 5, characterized in that The voltage unit obtains the real-time voltage of the charging circuit by using the current sampling unit, and sends the real-time voltage to the comparison unit; The comparison unit compares the real-time voltage with a reference voltage, and generates the target level or the digital code sequence according to a comparison structure.

7. The circuit according to claim 5, characterized in that The voltage unit includes: a differential amplifier, a first resistor, a second resistor, a third resistor, and a fourth resistor; the comparison unit includes: an in-phase comparator; The positive input terminal of the differential amplifier is electrically connected to the second end of the first resistor and the first end of the second resistor respectively; The second end of the second resistor is electrically connected to the current input end of the current sampling unit; A first end of the first resistor is grounded; The negative input terminal of the differential amplifier is electrically connected to the first end of the third resistor and the first end of the fourth resistor respectively; The second end of the third resistor is electrically connected to the output end of the differential amplifier and the in-phase end of the in-phase comparator; The second end of the fourth resistor is electrically connected to the current output end of the current sampling unit; The inverting terminal of the in-phase comparator receives a reference voltage; The output end of the in-phase comparator is electrically connected to the second asynchronous serial port.

8. The circuit according to claim 5, characterized in that When the battery is charging, the control module is configured to use the first asynchronous serial port to control the charging circuit to be continuously turned on; When communication is required, the control module is configured to first use the first asynchronous serial port to control the charging circuit to be turned off, and then configure the first asynchronous serial port as a data transmission port; or, The control module is configured to first configure the first asynchronous serial port as the data transmission port, and then use the first asynchronous serial port to control the charging circuit to be turned off; When communication is required, the control module is configured to use the first asynchronous serial port to send data bits in a corresponding order of the preset code to control the charging circuit to be turned on or off.

9. The circuit according to claim 5, characterized in that The voltage unit is configured so that when the battery is charged, the real-time voltage outputted by the voltage unit is always greater than the reference voltage; The voltage unit is configured such that when communication is required, the real-time voltage outputted by the voltage unit is greater than the reference voltage when the charging circuit is turned on, and is less than the reference voltage when the charging circuit is turned off; The comparison unit is configured to output a high level when the real-time voltage is greater than the reference voltage, and to output a low level when the real-time voltage is less than the reference voltage.

10. The circuit according to claim 1, characterized in that The circuit further comprises: a charging bypass; The charging bypass is connected to the input and output ports of the control module; The charging bypass is configured to be in an off state when the battery is being charged, and to be in an on state after the battery is completely charged.

11. The circuit according to claim 1, characterized in that The current sampling unit comprises: a current sampling resistor; The second end of the encoding module is connected across two ends of the current sampling resistor.

12. A battery management system, characterized in that: The battery management system comprises a circuit as claimed in any one of claims 1-11.

13. An electric energy system, characterized in that: The electric energy system includes: a battery module and a battery management system, and the battery management system is the battery management system according to claim 12.

14. The electric energy system according to claim 13, characterized in that: The number of the battery modules and the number of the battery management systems are both multiple and correspond one to one, and the multiple battery modules are connected in series.

15. The electric energy system according to claim 14, characterized in that: It also includes a plurality of charging bypasses which are connected to the plurality of battery modules in a one-to-one correspondence. When the battery management system controls the charging circuit of the corresponding battery to be disconnected, the battery management system controls the charging bypass to be closed.

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