A half-split circuit for charging and discharging of an electric bicycle protection board

Abstract

The present invention discloses a half-split charging and discharging circuit for an electric power-assisted bicycle protective board, comprising: a battery module, a control module, a discharge module, a charging module, a first current detection module, and a second current detection module; the discharge module is connected to the discharge control port of the control module, and the charging module is connected to the charging control port of the control module; the first current detection module is connected between the battery module and the discharge module, and the second current detection module is connected between the discharge module and the charging module; the two ends of the first current detection module are respectively connected to the first current detection port of the control module, and the two ends of the second current detection module are respectively connected to the second current detection port of the control module; the control module is used to control the opening and closing of the discharge module or the charging module, and judge the charge and discharge status of the battery module based on the detected currents of the first and second current detection modules. This can determine the charging status and monitor whether the discharge is normal, thereby avoiding safety hazards.

Description

Technical Field

[0001] The invention belongs to the technical field of batteries and relates to a half-split circuit for charging and discharging of a protective plate of an electric power-assisted bicycle. Background Art

[0002] During the actual operation of an electric power-assisted bicycle, the protection board system control is a very important component. It can monitor the battery status in real time and ensure that the power battery is always in the best working condition. At present, in order to make it easier for riders to distinguish between the charging and discharging ports, the protection board of an electric power-assisted bicycle is generally designed to have the same charging and discharging port. That is, when charging the battery pack, it needs to be removed from the bicycle to release the discharge plug, making the charging process more cumbersome. In addition, given the requirements for electric power-assisted bicycle chargers to be light, small, and have good heat dissipation, the charger is designed to have a smaller charging current than the discharge current. This requires that the charging MOS with a smaller overcurrent capacity needs to be consistent with the discharge MOS to allow the larger discharge current to flow through them together, thereby increasing R&D costs.

[0003] To avoid these drawbacks, protection boards with separate charging and discharging ports are being developed. The charging MOSFET can be selected with a lower overcurrent capability, saving costs and simplifying the charging process. However, due to the separate charging and discharging ports, battery risks cannot be detected promptly if the discharging MOSFET fails (short circuit or open circuit). Furthermore, the battery can be charged and discharged simultaneously, which can easily lead to accidents such as the vehicle slipping. Summary of the Invention

[0004] The purpose of the present invention is to provide a half-split charging and discharging circuit for an electric power-assisted bicycle protection board, which solves the problems of high cost of designing charging and discharging with the same port and the complicated charging and discharging process, and avoids the risk of discharge MOS tube failure in the full-split charging and discharging design and avoids the situation where the battery is discharged while charging.

[0005] The technical solution of the present invention is: a half-split circuit for charging and discharging of a protective board of an electric power-assisted bicycle, comprising: a battery module, a control module, a discharge module, a charging module, a first current detection module, and a second current detection module; the positive electrode port of the battery module is connected to the positive electrode port of the charge and discharge circuit; the discharge module is connected to the discharge control port of the control module, and the charging module is connected to the charging control port of the control module; the first current detection module is connected between the battery module and the discharge module, the second current detection module is connected between the discharge module and the charging module, and both ends of the first current detection module are respectively connected to the first current detection terminal of the control module port, both ends of the second current detection module are respectively connected to the second current detection port of the control module; the negative port of the battery module is connected to the negative port of the discharge circuit through the first current detection module and the discharge module in sequence, and the negative port of the battery module is connected to the negative port of the charging circuit through the first current detection module, the discharge module, the second current detection module and the charging module in sequence; the control module is used to control the opening and closing of the discharge module or the charging module, determine whether the battery module is in a charging state according to the detection current of the second current detection module, and determine the current size of the power circuit according to the detection current of the first current detection module.

[0006] Through the half-split charging and discharging circuit, the current flows through the charging module, the discharging module, the first current detection module, and the second current detection module at the same time. By detecting the current of the first current detection module and the second current detection module through the control module, the charging status can be judged and the discharge can be monitored to avoid safety hazards.

[0007] Its further technical solution is: the first current detection module includes a first current detection resistor R1, the second current detection module includes a second current detection resistor R2, the discharge module includes a discharge MOS Q1, and the charging module includes a charge MOS Q2; one end of the first current detection resistor R1 is connected to the negative electrode port of the battery module, and the other end is connected to the source of the discharge MOS Q1; the source and gate of the discharge MOS Q1 are connected to the discharge control port of the control module, and the drain of the discharge MOS Q1 is connected to the negative electrode port of the discharge circuit; one end of the second current detection resistor R2 is connected to the drain of the discharge MOS Q1, and the other end is connected to the drain of the charge MOS Q2; the source and gate of the charge MOS Q2 are connected to the charge control port of the control module, and the source of the charge MOS Q2 is connected to the negative electrode port of the charging circuit; the two ends of the first current detection resistor R1 are respectively connected to the first current detection port of the control module, and the two ends of the second current detection resistor R2 are respectively connected to the second current detection port of the control module.

[0008] Through the half-split charging and discharging circuit composed of the first current-sense resistor, the discharge MOS, the second current-sense resistor, and the charging MOS, the current flows through the charge and discharge MOS and the current-sense resistor at the same time during charging, and the charging current can be detected to confirm that the charging circuit is more stable during the charging process; when the discharge MOS failure mode is power-off, the discharge MOS is always closed to ensure that neither charging nor discharging is possible; when the discharge MOS failure mode is short circuit, the battery can be charged and discharged without enabling the discharge MOS to be closed, and the MCU will issue an error warning to avoid charging and discharging. Specific measures include disconnecting the charging MOS when the battery is in the charging state and disconnecting the load when the battery is in the discharging state; the half-split design makes the charging and discharging process simpler, and the charging MOS and the discharge MOS do not need to be consistent, which is convenient for cost saving; by comparing and analyzing the currents of the two current-sense resistors through the control module, the charging and discharging status of the battery can be judged to avoid accidents caused by misoperation.

[0009] A further technical solution is: the discharging MOS Q1 and the charging MOS Q2 are both composed of an N-channel MOS tube and a parasitic diode, the anode of the parasitic diode is connected to the source of the N-channel MOS tube, and the cathode of the parasitic diode is connected to the drain of the N-channel MOS tube.

[0010] The switch MOS is composed of an N-channel MOS tube and a parasitic diode, and the switch MOS can be turned on and off by the control module.

[0011] A further technical solution is that the number of N-channel MOS tubes and parasitic diodes included in the discharging MOS Q1 is greater than that in the charging MOS Q2.

[0012] Since the current of the half-split charge and discharge circuit flows through the charge and discharge MOS at the same time during charging, and only flows through the discharge MOS during discharging, the number of MOS tubes and parasitic diodes in the discharge MOS is more than that in the charge MOS to meet actual working requirements.

[0013] Its further technical solution is: the control module includes an analog front-end IC and an MCU; the analog front-end IC and the MCU communicate via I2C; the two ends of the first current-sensing resistor R1 are respectively connected to the first current detection port on the analog front-end IC, and the two ends of the second current-sensing resistor R2 are respectively connected to the second current detection port on the MCU; the gate of the discharge MOS Q1 is connected to the discharge control port on the analog front-end IC, and the gate of the charge MOS Q2 is connected to the charge control port on the analog front-end IC.

[0014] The analog front-end IC can collect the cell voltage and the voltage of the current-sense resistor, and then collect the current and control the opening and closing of the charge and discharge MOS; the analog front-end IC and the MCU obtain battery information through I2C communication, and then compare the current of the first current-sense resistor with the current of the second current-sense resistor to determine the corresponding charge and discharge status.

[0015] A further technical solution is: a first source resistor and a first voltage regulator are connected in parallel in series between the source of the discharge MOS Q1 and the discharge control port of the control module, and a first gate resistor is connected in series between the gate of the discharge MOS Q1 and the discharge control port of the control module; a second source resistor and a second voltage regulator are connected in parallel in series between the source of the charge MOS Q2 and the charge control port of the control module, and a second gate resistor is connected in series between the gate of the charge MOS Q2 and the charge control port of the control module.

[0016] By setting the gate resistor and the source resistor as a discharge resistor, a small amount of static electricity between the gate and the source is discharged to prevent the MOS tube from malfunctioning, provide a bias voltage for the MOS tube, and stabilize the voltage between the gate and the source through the voltage regulator tube.

[0017] A further technical solution is: a fuse is connected in series between the positive electrode port of the battery module and the positive electrode port of the charge and discharge circuit.

[0018] The safe operation of the circuit is protected by fuses. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The present invention will be further described below with reference to the accompanying drawings and embodiments:

[0020] Figure 1 This is a structural block diagram of the charging and discharging half-split circuit of the electric power-assisted bicycle protection board provided by this application;

[0021] Figure 2 This is a circuit diagram of the charging and discharging half-split circuit of the electric power-assisted bicycle protection board provided by this application. DETAILED DESCRIPTION

[0022] Example: This application provides a half-split circuit for charging and discharging of an electric power-assisted bicycle protection board, combined with reference Figure 1 and Figure 2 The half-split charging and discharging circuit includes: a battery module, a control module, a discharge module, a charging module, a first current detection module, and a second current detection module.

[0023] The positive port B+ of the battery module is connected to the positive port P+ / C+ of the charge and discharge circuit; the discharge module is connected to the discharge control port of the control module, and the charging module is connected to the charging control port of the control module; the first current detection module is connected between the battery module and the discharge module, and the second current detection module is connected between the discharge module and the charging module. The two ends of the first current detection module are respectively connected to the first current detection port of the control module, and the two ends of the second current detection module are respectively connected to the second current detection port of the control module; the negative port B- of the battery module is connected to the negative port P- of the discharge circuit through the first current detection module and the discharge module in sequence, and the negative port B- of the battery module is connected to the negative port C- of the charging circuit through the first current detection module, the discharge module, the second current detection module and the charging module in sequence.

[0024] like Figure 2 As shown, the first current detection module includes a first current detection resistor R1, the second current detection module includes a second current detection resistor R2, the discharge module includes a discharge MOS Q1 (DSG MOS), and the charging module includes a charging MOS Q2 (CHG MOS).

[0025] One end of the first current-sense resistor R1 is connected to the negative terminal B- of the battery module (Battery), and the other end is connected to the source of the discharge MOS Q1; the source and gate of the discharge MOS Q1 are connected to the discharge control port DSG_CTL of the control module, and the drain of the discharge MOS Q1 is connected to the negative terminal P- of the discharge circuit; one end of the second current-sense resistor R2 is connected to the drain of the discharge MOS Q1, and the other end is connected to the drain of the charge MOS Q2; the source and gate of the charge MOS Q2 are connected to the charge control port CHG_CTL of the control module, and the source of the charge MOS Q2 is connected to the negative terminal C- of the charging circuit.

[0026] Both ends of the first current detection resistor R1 are respectively connected to the first current detection port Currentdetect1 of the control module, and both ends of the second current detection resistor R2 are respectively connected to the second current detection port Currentdetect2 of the control module.

[0027] The discharging MOS Q1 and the charging MOS Q2 are both composed of an N-channel MOS tube and a parasitic diode. The anode of the parasitic diode is connected to the source of the N-channel MOS tube, and the cathode of the parasitic diode is connected to the drain of the N-channel MOS tube.

[0028] The number of N-channel MOS tubes and parasitic diodes included in the discharge MOS Q1 is greater than that of the charge MOS Q2. Figure 2The discharge MOS Q1 consists of three MOS transistors and a parasitic diode, while the charge MOS Q2 consists of a single MOS transistor and a parasitic diode. The numbers in the diagram are general in nature; in actual applications, the required currents are determined based on the circuit's charge and discharge currents. Typically, the charge current is 0.3C or 0.5C, and the discharge current is 1.5C or 2C. (For example, if the battery capacity is 10AH, the 0.5C current is 5A, the 0.3C current is 3A, the 1.5C current is 15A, and the 2C current is 20A.) Since the charge in the half-split circuit flows through both the charge and discharge MOSs, while the discharge only flows through the discharge MOS, the number of MOS used for charging is smaller than that for discharging.

[0029] The control module is used to control the opening and closing of the discharge module or the charging module, determine whether the battery module is in a charging state according to the detection current of the second current detection module, and determine the current size of the power circuit according to the detection current of the first current detection module.

[0030] Optionally, the control module includes an analog front-end IC (AFE IC) and an MCU; the analog front-end IC and the MCU communicate via I2C.

[0031] The two ends of the first current detection resistor R1 are respectively connected to the first current detection port Currentdetect1 on the analog front-end IC, and the two ends of the second current detection resistor R2 are respectively connected to the second current detection port Currentdetect2 on the MCU; the gate of the discharge MOS Q1 is connected to the discharge control port DSG_CTL on the analog front-end IC, and the gate of the charging MOS Q2 is connected to the charging control port CHG_CTL on the analog front-end IC.

[0032] The analog front-end IC can collect the single cell voltage, collect the voltage of the first current-sense resistor R1 (precision resistor), and then collect the current, and control the opening and closing of the charge and discharge MOS. The MCU and the analog front-end IC obtain battery information through I2C communication, and compare the current of R1 collected by the AFEIC with the current of R2 collected by the MCU to determine the corresponding charge and discharge status.

[0033] The AFE IC (Analog Front-End IC) is a digital front-end chip for lithium-ion battery BMSs. It collects battery cell voltage and current and controls MOS shutdown. In protection mode, it independently protects the lithium-ion battery pack, providing overcharge, over-discharge, temperature, charge and discharge overcurrent, short-circuit, and secondary overcharge protection. An integrated balancing switch improves cell consistency. In acquisition mode, it collaborates with the MCU to manage the lithium-ion battery pack while enabling all protection functions.

[0034] Since the AFE IC has only one current detection channel, the other comparison current (the current on R2) can only be detected by the MCU, and the comparison analysis is used to determine the corresponding charge and discharge status.

[0035] To ensure circuit reliability, a first source resistor Rs1 and a first voltage regulator ZD1 are connected in parallel between the source of the discharge MOS Q1 and the discharge control port DSG_CTL of the control module, and a first gate resistor Rg1 is connected in series between the gate of the discharge MOS Q1 and the discharge control port DSG_CTL of the control module.

[0036] A second source resistor Rs2 and a second voltage regulator ZD2 are connected in parallel between the source of the charging MOS Q2 and the charging control port CHG_CTL of the control module. A second gate resistor Rg2 is connected in parallel between the gate of the charging MOS Q2 and the charging control port CHG_CTL of the control module.

[0037] The gate resistor and source resistor are discharge resistors, which are used to discharge a small amount of static electricity between the gate and source to prevent the MOS tube from malfunctioning and provide bias voltage for the MOS tube. The voltage regulator is used to stabilize and protect the voltage between the gate and source.

[0038] In practical applications, if the discharge MOS Q1 or the charge MOS Q2 includes multiple groups of MOS tubes, each MOS tube is connected to a corresponding gate resistor, and for the source resistor and the voltage regulator tube, multiple MOS tubes can be connected to the same source resistor and voltage regulator tube.

[0039] A fuse is connected in series between the positive terminal B+ of the battery module and the positive terminal P+ / C+ of the charge and discharge circuit.

[0040] In actual applications of the charging and discharging half-split circuit of the electric power-assisted bicycle protection board provided in this application, the MCU can detect the charging current through the second current-sense resistor R2 to determine whether the battery is in a charging state, and the analog front-end IC can determine the current size of the power circuit by detecting the first current-sense resistor R1, and can control the opening and closing of the power circuit charging and discharging MOS.

[0041] The currents in the first current-sense resistor R1 and the second current-sense resistor R2 can be compared and analyzed. When the battery is charging, the charging current flowing through the second current-sense resistor R2 is consistent with the current flowing through the first current-sense resistor R1. If the current I1 flowing through the first current-sense resistor R1 is smaller than the current I2 flowing through the second current-sense resistor R2, or if the sign of I2 is opposite to that of I1, this indicates that the battery is still discharging while charging. In this case, controlling the discharge MOS to disconnect terminates the simultaneous charging and discharging of the battery. When the battery is discharging, the discharge current is detected in the first current-sense resistor R1, while no charging current is detected in the second current-sense resistor R2. If there is a charging current in the first current-sense resistor R1, it can be determined that charging and discharging are occurring simultaneously.

[0042] It can be seen from this that when charging, the current of the half-split circuit of charge and discharge flows through the charge and discharge MOS and the current-sense resistor at the same time. The charging current can be detected to determine that it is in the charging process, and the charging circuit is more stable. When the failure mode of the discharge MOS is open circuit, the discharge MOS can never be opened to ensure that charging and discharging are not possible; when the failure mode of the discharge MOS is short circuit, the battery can be charged and discharged without enabling the discharge MOS to be closed, and the MCU will issue an error warning to avoid charging and discharging. The specific measures include: disconnecting the charging MOS when the battery is in the charging state, and disconnecting the load when the battery is in the discharging state. The half-split design makes the charging and discharging process simpler, and the discharge MOS Q1 series and the charging MOS Q2 series do not need to be consistent, which is convenient for cost saving. In addition, by comparing and analyzing the current of the first current-sense resistor R1 and the second current-sense resistor R2, the charging and discharging status of the battery can be clearly judged to avoid accidents caused by misoperation.

[0043] To sum up, the charging and discharging half-split circuit of the electric power-assisted bicycle protection board provided in this application, through the charging and discharging half-split circuit, the current flows through the charging module, the discharging module, the first current detection module, and the second current detection module at the same time. By detecting the current of the first current detection module and the second current detection module through the control module, the charging status can be judged and the discharge can be monitored to see whether it is normal, thereby avoiding safety hazards.

[0044] In addition, through the charging and discharging half-split circuit composed of the first current-sense resistor, the discharge MOS, the second current-sense resistor, and the charging MOS, the current flows through the charge and discharge MOS and the current-sense resistor at the same time during charging, and the charging current can be detected to confirm that the charging circuit is more stable during the charging process; when the discharge MOS failure mode is power-off, the discharge MOS is always closed to ensure that neither charging nor discharging is possible; when the discharge MOS failure mode is short circuit, the battery can be charged and discharged without enabling the discharge MOS to be closed, and the MCU will issue an error warning to avoid charging and discharging. Specific measures include disconnecting the charging MOS when the battery is in the charging state and disconnecting the load when the battery is in the discharging state; the half-split design makes the charging and discharging process simpler, and the charging MOS and the discharge MOS do not need to be consistent, which is convenient for cost saving; by comparing and analyzing the currents of the two current-sense resistors through the control module, the charging and discharging status of the battery can be judged to avoid accidents caused by misoperation.

[0045] In addition, a switch MOS is formed by an N-channel MOS tube and a parasitic diode, and the switch MOS can be turned on and off by a control module.

[0046] In addition, since the current of the half-split charging and discharging circuit flows through the charging and discharging MOS at the same time during charging, and only passes through the discharging MOS during discharging, the number of MOS tubes and parasitic diodes in the discharging MOS is more than that in the charging MOS to meet actual working requirements.

[0047] In addition, the analog front-end IC can collect the cell voltage and the voltage of the current-sense resistor, and then collect the current and control the opening and closing of the charging and discharging MOS; the analog front-end IC and the MCU obtain battery information through I2C communication, and then compare the current of the first current-sense resistor and the current of the second current-sense resistor to determine the corresponding charging and discharging status.

[0048] In addition, by setting the gate resistor and the source resistor as a discharge resistor, a small amount of static electricity between the gate and the source is discharged to prevent the MOS tube from malfunctioning, provide a bias voltage for the MOS tube, and stabilize the voltage between the gate and the source through the voltage regulator tube.

[0049] In addition, the safe operation of the circuit is protected by fuses.

[0050] The terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or the number of the technical features indicated. Thus, a feature specified as "first" or "second" may explicitly or implicitly include one or more of such features. In the description of this application, unless otherwise specified, "plurality" means two or more.

[0051] The serial numbers of the above embodiments of the present application are for description only and do not represent the advantages or disadvantages of the embodiments.

[0052] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present application should be included in the scope of protection of the present application.

Claims

1. A half-split circuit for charging and discharging of an electric power-assisted bicycle protection board, characterized in that: include: Battery module, control module, discharge module, charging module, first current detection module, second current detection module; The positive electrode port of the battery module is connected to the positive electrode port of the charge and discharge circuit; The discharge module is connected to the discharge control port of the control module, and the charging module is connected to the charging control port of the control module; The first current detection module is connected between the battery module and the discharge module, and the second current detection module is connected between the discharge module and the charging module. Both ends of the first current detection module are respectively connected to the first current detection port of the control module, and both ends of the second current detection module are respectively connected to the second current detection port of the control module. The negative electrode port of the battery module is connected to the negative electrode port of the discharge circuit through the first current detection module and the discharge module in sequence, and the negative electrode port of the battery module is connected to the negative electrode port of the charging circuit through the first current detection module, the discharge module, the second current detection module and the charging module in sequence; The control module is used to control the opening and closing of the discharge module or the charging module, determine whether the battery module is in a charging state according to the detection current of the second current detection module, and determine the current size of the power circuit according to the detection current of the first current detection module; The first current detection module includes a first current detection resistor R1, the second current detection module includes a second current detection resistor R2, the discharge module includes a discharge MOS Q1, and the charging module includes a charge MOS Q2; One end of the first current-sense resistor R1 is connected to the negative terminal of the battery module, and the other end is connected to the source of the discharge MOS Q1; the source and gate of the discharge MOS Q1 are connected to the discharge control port of the control module, and the drain of the discharge MOS Q1 is connected to the negative terminal of the discharge circuit; one end of the second current-sense resistor R2 is connected to the drain of the discharge MOS Q1, and the other end is connected to the drain of the charge MOS Q2; the source and gate of the charge MOS Q2 are connected to the charge control port of the control module, and the source of the charge MOS Q2 is connected to the negative terminal of the charging circuit; The two ends of the first current detection resistor R1 are respectively connected to the first current detection port of the control module, and the two ends of the second current detection resistor R2 are respectively connected to the second current detection port of the control module; Comparative analysis of the currents of the first current-sense resistor R1 and the second current-sense resistor R2 shows that when the battery is charging, the charging current flowing through the second current-sense resistor R2 is consistent with the current flowing through the first current-sense resistor R1; If the current I1 flowing through the first current-sense resistor R1 is smaller than the current I2 flowing through the second current-sense resistor R2, or the sign of I2 is opposite to that of I1, it indicates that the battery is still discharging during charging. At this time, the discharge control MOS is disconnected to terminate the simultaneous charging and discharging process of the battery. When the battery is discharging, the discharge current is detected on the first current-sense resistor R1, and no charging current is detected on the second current-sense resistor R2. If the charging current is detected on the first current-sense resistor R1, it is determined that charging and discharging are occurring simultaneously.

2. The charging and discharging half-split circuit of the electric power-assisted bicycle protection board according to claim 1 is characterized in that: The discharging MOS Q1 and the charging MOS Q2 are both composed of an N-channel MOS transistor and a parasitic diode, wherein the anode of the parasitic diode is connected to the source of the N-channel MOS transistor, and the cathode of the parasitic diode is connected to the drain of the N-channel MOS transistor.

3. The charging and discharging half-split circuit of the electric power-assisted bicycle protection board according to claim 2 is characterized in that: The number of N-channel MOS transistors and parasitic diodes included in the discharging MOS Q1 is greater than that in the charging MOS Q2.

4. The charging and discharging half-split circuit of the electric power-assisted bicycle protection board according to claim 1, characterized in that: The control module includes an analog front-end IC and an MCU; The analog front-end IC and the MCU communicate via I2C; The two ends of the first current detection resistor R1 are respectively connected to the first current detection port on the analog front-end IC, and the two ends of the second current detection resistor R2 are respectively connected to the second current detection port on the MCU; The gate of the discharge MOS Q1 is connected to the discharge control port on the analog front-end IC, and the gate of the charge MOS Q2 is connected to the charge control port on the analog front-end IC.

5. The charging and discharging half-split circuit of the electric power-assisted bicycle protection board according to claim 1, characterized in that: A first source resistor and a first voltage regulator tube are connected in parallel between the source of the discharge MOS Q1 and the discharge control port of the control module, and a first gate resistor is connected in series between the gate of the discharge MOS Q1 and the discharge control port of the control module; A second source resistor and a second voltage regulator are connected in parallel between the source of the charging MOS Q2 and the charging control port of the control module, and a second gate resistor is connected in parallel between the gate of the charging MOS Q2 and the charging control port of the control module.

6. The half-split circuit for charging and discharging of the protection board of the electric power-assisted bicycle according to any one of claims 1 to 5, characterized in that: A fuse is connected in series between the positive electrode port of the battery module and the positive electrode port of the charge and discharge circuit.

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