Rechargeable battery management system

Abstract

The utility model relates to a rechargeable battery management system, which is characterized in that a No.2 pin GND of a power management chip U2 is connected with a ground wire GND, a No.3 output pin OUT of the power management chip U2 is connected with an external battery V18650, a No.4 pin PWM of the power management chip U2 is connected with a microcontroller MCU, a No.5 pin IN of the power management chip U2 is connected with a + 5V direct current power supply B, and a No.3 output pin OUT of the power management chip U2 is connected with an external battery V18650. And a sixth pin CHGB of the power management chip U2 is connected with a digital circuit power input end DDVDD. The circuit is simple, the cost is low, the sensitivity is high, and the adaptability and the practicability are high; the voltage and the charging state of the battery can be detected through the GPIO, so that the charging current is controllable; when voltage is too low due to long-time use of the battery, battery power supply is actively cut off, and the service life of the battery is protected and prolonged.

Description

TECHNICAL FIELD

[0001] The utility model relates to the field of battery management system especially, a kind of charging battery management system. BACKGROUND

[0002] Due to the power supply system of overseas partial area stable power supply period has unpredictability, the charging battery of smart meter external, its main role is to provide a kind of standby power supply solution, to ensure that smart meter still can keep the normal operation of key function when AC power supply is disconnected.Specific role includes:

[0003] (1) reserve clock information: when power grid is powered off, battery can continue to power for the real-time clock inside the meter, ensure the accuracy and continuity of clock, this is particularly important for the smart meter of implementing time-of-use pricing billing.

[0004] (2) data preservation: battery can ensure that during power failure, the power consumption data stored inside the meter, such as: total power consumption, real-time power, rate period data, etc. will not be lost, these data need to be accurately uploaded to the management system of power company after power recovery.

[0005] (3) communication maintenance: in some designs, external battery can provide temporary power when power grid is powered off, support smart meter to report key state information or upload data through WIFI, GPRS, 4G, NB-loT, Emtc, LoRa, Zigbee, RF, PLC carrier and other communication modules, which is crucial for remote meter reading and fault monitoring functions.

[0006] (4) prepayment meter function maintenance: for prepayment meter, external battery can make the meter maintain basic functions such as remaining power display, arrear warning, etc. when main power is disconnected, until power recovery or user recharge.

[0007] (5) emergency operation: in extreme cases, battery can also provide short-term emergency operation capability for the meter, such as performing necessary system check and maintenance procedures during power grid failure. In summary, the charging battery external to the smart meter plays a crucial role, not only enhances the stability and reliability of the meter under abnormal power supply conditions, but also ensures the continuity of power service and the safety of data.

[0008] The existing external battery of smart meter has the problem of overcharge and overdischarge, and charging when current is unstable, which can cause battery damage and life decline. INVENTION CONTENTS

[0009] The utility model aims at solving above-mentioned problem, provides a kind of charging battery management system, solves above-mentioned problem.

[0010] A rechargeable battery management system, comprising: a power management chip U2, an external battery V18650, a DC power supply B and a digital circuit power input end D_DVDD, the No. 2 pin GND of the power management chip U2 is connected with the ground wire GND, the No. 3 output pin OUT of the power management chip U2 is connected with the external battery V18650, the No. 4 pin PWM of the power management chip U2 is connected with the microcontroller MCU, the No. 5 pin IN of the power management chip U2 is connected with the DC power supply B of +5V, and the No. 6 pin CHGB of the power management chip U2 is connected with the digital circuit power input end D_DVDD.

[0011] Further, it further comprises a resistor R1, one end of which is connected with the digital circuit power input end D_DVDD, and the other end is connected with the No. 6 pin CHGB of the rechargeable power management chip U2; and further comprises a capacitor C2, which is connected between the ground wire GND and the No. 6 pin CHGB of the power management chip U2.

[0012] Further, it further comprises a resistor R2 and a capacitor C8, one end of the resistor R2 is connected with the ground wire GND, and the other end is connected with the No. 4 pin PWM of the rechargeable power management chip U2, and the capacitor C8 is connected in parallel across the resistor R2.

[0013] Further, it further comprises a resistor R3, one end of which is connected with the external battery V18650 and the No. 3 output pin OUT of the power chip U2, and the other end is connected with the battery voltage monitoring GPIO port Battery_18650_ADC of the microcontroller MCU.

[0014] Further, it further comprises a resistor R10 and a capacitor C3, the resistor R10 is connected between the battery voltage monitoring GPIO port Battery_18650_ADC of the microcontroller MCU and the ground wire GND, and the capacitor C3 is connected in parallel across the resistor R10, i.e. between the battery voltage monitoring GPIO port Battery_18650_ADC and the ground wire GND.

[0015] Further, it further comprises a capacitor C1 and a capacitor C6, which are connected between the external battery V18650 and the ground wire GND, and are connected between the No. 3 output pin OUT of the power management chip U2 and the ground wire GND.

[0016] Further, it further comprises a capacitor C4 and a capacitor C5, which are connected between the No. 5 pin IN of the power chip U2 and the ground wire GND.

[0017] Further, the power supply chip U1 is further provided, a No.

[0018] Further, the power supply chip U1 is further provided, a No.

[0019] Further, the power supply management chip U2 is SY6978 chip.

[0020] The utility model has the advantages of:

[0021] 1, simple circuit, low cost, high sensitivity, high adaptability and practicality;

[0022] 2, through GPIO can detect battery voltage and charging state, realize the controllable of charging current;

[0023] 3, when the voltage is too low caused by long time use of battery, the battery power supply is actively cut off, and the battery service life is protected and prolonged. BRIEF DESCRIPTION OF DRAWINGS

[0024] In order to more clearly illustrate the technical scheme in the embodiment of the utility model or prior art, the following will be briefly introduced to the drawing needed to be used in the embodiment or prior art description. Obviously, the drawing in the following description is only one embodiment of the utility model, and for those skilled in the art, other embodiment drawings can be obtained according to the provided drawing without creating creative labor.

[0025] Fig. 1 The circuit diagram of the utility model;

[0026] Fig. 2 The pin diagram of microprocessor;

[0027] Fig. 3 The flow chart of the utility model. DETAILED DESCRIPTION

[0028] The utility model will be further described below in combination with the drawings and examples:

[0029] The embodiments of the present application are described below in detail, examples of the embodiments are shown in the drawings, wherein the same or similar notations represent the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the drawings are exemplary, only for explaining the present application, and cannot be understood as a limitation of the present application.

[0030] In the description of the present application, it should be explained that, unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connection" should be understood in a broad sense, for example, it can be fixed connection, or detachable connection, or integrally connected, it can be directly connected, or indirectly connected through intermediate medium. For ordinary skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0031] In the description of the present application, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship shown in the drawings, which is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, therefore it cannot be understood as a limitation of the present application.

[0032] As shown in Figs. 1 to 3 A charging battery management system, comprising: a power management chip U2, an external battery V18650, a DC power supply B and a digital circuit power input end D_DVDD, the No. 2 pin GND of the power management chip U2 is connected with the ground wire GND, the No. 3 output pin OUT of the power management chip U2 is connected with the external battery V18650, the No. 4 pin PWM of the power management chip U2 is connected with the microcontroller MCU, the No. 5 pin IN of the power management chip U2 is connected with the DC power supply B of +5V, and the No. 6 pin CHGB of the power management chip U2 is connected with the digital circuit power input end D_DVDD. Wherein, the microcontroller MCU is the microcontroller MCU of the electric meter.

[0033] Further, it further comprises a resistor R1, one end of the resistor R1 is connected with the digital circuit power input end D_DVDD, and the other end is connected with the No. 6 pin CHGB of the charging power management chip U2; and further comprising a capacitor C2, which is connected between the ground wire GND and the No. 6 pin CHGB of the power management chip U2.

[0034] Further, it further comprises a resistor R2 and a capacitor C8, one end of the resistor R2 is connected with the ground wire GND, the other end is connected with the No. 4 pin PWM of the charging power management chip U2, and the capacitor C8 is connected in parallel across the resistor R2.

[0035] Further, it further includes a resistor R3, one end of which is connected to the external battery V18650 and the No. 3 output pin OUT of the power supply chip U2, and the other end is connected to the battery voltage monitoring GPIO port Battery_18650_ADC of the microcontroller MCU.

[0036] Further, it further includes a resistor R10 and a capacitor C3, the resistor R10 is connected between the battery voltage monitoring GPIO port Battery_18650_ADC of the microcontroller MCU and the ground wire GND, and the capacitor C3 is connected in parallel between the resistor R10. That is, between the battery voltage monitoring GPIO port Battery_18650_ADC and the ground wire GND.

[0037] Further, it further includes a capacitor C1 and a capacitor C6, which are connected between the external battery V18650 and the ground wire GND, and are connected between the No. 3 output pin OUT of the power management chip U2 and the ground wire GND.

[0038] Further, it further includes a capacitor C4 and a capacitor C5, which are connected between the No. 5 pin IN of the power supply chip U2 and the ground wire GND.

[0039] Further, it further includes a power supply chip U1, the No. 1 pin PCKP of which is connected to the external battery V18650, the No. 6 pin BYPS of which is connected to the battery ground wire BGND, and the No. 2 pin of which is connected to the ground wire GND.

[0040] Further, it further includes a resistor R11 connected between the external battery V18650 and the No. 1 pin PCKP of the power supply chip U1; and a capacitor C10 connected between the No. 6 pin BYPS of the power supply chip U1 and the battery ground wire BGND.

[0041] Further, the power management chip U2 is a SY6978 chip.

[0042] Working principle:

[0043] The resistor R3 and the resistor R10 constitute a voltage division circuit, and provide a detection signal for a voltage detection pin (a battery voltage monitoring GPIO port Battery_18650_ADC) of the microcontroller MCU; the capacitor C2 is designed to provide an initial state for a high resistance state output pin; the capacitor C4 and the capacitor C5 are decoupling capacitors in an IN and B+ 5V network of a No. 5 pin of the power management chip U2 (a SY6978 chip); the power management chip U2 (the SY6978 chip) can charge the external battery V18650 (a lithium ion battery) in a pre-charge, constant current (CC) mode or a constant voltage (CV) mode. When the voltage of the external battery V18650 is less than Vpchg (a pre-charge constant-charge transition rising threshold value), the power management chip U2 pre-charges the external battery V18650, and this function can restore the vitality of a deeply discharged battery and protect the service life of the battery. The pre-charge rate determined internally is 15% of a constant charging current. The charging current in the CC mode is determined by the duty cycle of a PWM signal. The CC current can be calculated by the following formula: Icc=500×PWM signal duty cycle (mA), and a PWM signal frequency in a range of 20 kHz to 200 kHz can be used, and the PWM signal frequency and the output current ripple are inversely proportional to the growth. When the voltage of the external battery V18650 approaches a battery voltage stabilization threshold value, the power management chip U2 enters a voltage stabilization stage, and the voltage stabilization state of the external battery V18650 is fed back through the No. 3 output pin OUT, so as to monitor the battery voltage between the No. 3 output pin OUT and the ground wire GND pin.

[0044] The power management chip U2 receives a voltage current from the No. 5 pin IN pin in the B+ 5V network, receives a pulse width modulation signal output by the microcontroller MCU through the No. 4 pin PWM to control the output current, and the No. 6 pin CHGB is in a low resistance state when the detected output voltage difference is positive. The microcontroller MCU can detect that it is in a charging state. When the voltage stabilization charging stage ends, that is, the battery voltage reaches an upper limit, the power management chip U2 automatically accesses a high resistance mode, indicating that the charging process has ended. In addition, in order to ensure that the PWM pulse width modulation signal maintains a good waveform at the receiving end of the chip, an RC filter circuit composed of the resistor R2 and the capacitor C8 is connected, which effectively prevents distortion and deformation of the PWM high-frequency signal caused by interference crosstalk noise.

[0045] The discharging process is controlled by the power chip U1 (a lithium battery protection chip). The SGM41100A-430O05 presets a maximum detection voltage of 4.3V and a minimum voltage of 2.8V. When the voltage of the external battery V18650 exceeds 4.3V or is lower than 2.8V, the ground wire GND connected to the first pin PCKN interface of the power chip U1 and the battery ground wire BGND connected to the second pin BATN interface of the power chip U1 are disconnected, so that the battery is forced to be disconnected from the power supply circuit, thereby preventing over-discharge of the battery.

[0046] The battery management system (BMS) and the power chip U1 (lithium battery protection chip) take measures to prevent the external battery V18650 (lithium battery) from overcharging and overdischarging, the BMS continuously monitors the voltage of the external battery, and sets a voltage threshold, when the battery cell voltage reaches the preset highest charging termination voltage (overcharge protection threshold), the BMS will immediately cut off the charging circuit to prevent the battery from overcharging. Similarly, when the external battery voltage is detected to drop to the minimum discharge termination voltage (overdischarge protection threshold), the power chip U1 will stop the discharge of the battery cell to prevent overdischarge. At the same time, the charging current is controlled to prevent the charging current from exceeding the safety threshold to prevent excessive current from causing the battery to overheat or damage.

[0047] The system mainly uses the Silicon Power SY6987A linear DC charging management chip to control the charging process, with its pre-set constant current / constant voltage / pre-charge three modes, and adjusts the output current through the PWM signal output by the microprocessor MCU of the smart meter, which can reach up to 500mA, and outputs the charging indication signal to the microprocessor MCU in the open drain state pin, when the external battery V18650 voltage approaches the threshold, it enters the voltage stabilization stage, reduces the charging current, and continues to monitor the battery voltage when the external battery V18650 voltage reaches or exceeds the set voltage, when the external battery V18650 voltage drops below the threshold voltage through hysteresis, the charging current is restored. The SGM41100-430O04YUDT6G lithium protection chip controls the discharge process, and when the external battery V18650 voltage is detected to decrease to the set threshold ± hysteresis amplitude range, the external battery V18650 power supply is cut off to ensure that the external battery V18650 voltage will not decrease to the damaged voltage interval.

[0048] The power chip U1 also includes short circuit protection and temperature protection functions. Short circuit protection: when a short circuit is detected at the output end, the power supply path is quickly disconnected to avoid damage to the battery due to large current flowing through it for a short time. Temperature protection: monitors the working temperature of the battery, if the temperature exceeds the safe range, measures such as stopping charging or discharging are taken to prevent danger caused by high temperature.

[0049] The above has described the utility model by way of example, but the utility model is not limited to the above specific embodiments, any modification or modification based on the utility model belongs to the scope of protection required by the utility model.

Claims

1. A rechargeable battery management system, characterized by, It includes: The power management chip U2, the external battery V18650, the DC power supply B and the digital circuit power supply input end D_DVDD, the No. 2 pin GND of the power management chip U2 is connected with the ground wire GND, the No. 3 output pin OUT of the power management chip U2 is connected with the external battery V18650, the No. 4 pin PWM of the power management chip U2 is connected with the microcontroller MCU, the No. 5 pin IN of the power management chip U2 is connected with the DC power supply B of +5V, and the No. 6 pin CHGB of the power management chip U2 is connected with the digital circuit power supply input end D_DVDD.

2. A rechargeable battery management system according to claim 1, wherein: It also includes a resistor R1, one end of which is connected with the digital circuit power supply input end D_DVDD, and the other end is connected with the No. 6 pin CHGB of the charging power management chip U2; and a capacitor C2, which is connected between the ground wire GND and the No. 6 pin CHGB of the power management chip U2.

3. A rechargeable battery management system according to claim 1, wherein: It also includes a resistor R2 and a capacitor C8, one end of the resistor R2 is connected with the ground wire GND, and the other end is connected with the No. 4 pin PWM of the charging power management chip U2, and the capacitor C8 is connected in parallel across the resistor R2.

4. A rechargeable battery management system according to claim 1, wherein: It also includes a resistor R3, one end of which is connected with the external battery V18650 and the No. 3 output pin OUT of the power chip U2, and the other end is connected with the battery voltage monitoring GPIO port Battery_18650_ADC of the microcontroller MCU.

5. A rechargeable battery management system according to claim 1, wherein: It also includes a resistor R10 and a capacitor C3, the resistor R10 is connected between the battery voltage monitoring GPIO port Battery_18650_ADC of the microcontroller MCU and the ground wire GND, and the capacitor C3 is connected in parallel across the resistor R10, i.e. between the battery voltage monitoring GPIO port Battery_18650_ADC and the ground wire GND.

6. A rechargeable battery management system according to claim 1, wherein: It also includes a capacitor C1 and a capacitor C6, which are connected between the external battery V18650 and the ground wire GND, and are connected between the No. 3 output pin OUT of the power management chip U2 and the ground wire GND.

7. A rechargeable battery management system according to claim 1, wherein: It also includes a capacitor C4 and a capacitor C5, which are connected between the No. 5 pin IN of the power chip U2 and the ground wire GND.

8. A rechargeable battery management system according to claim 1, wherein: It also includes a power chip U1, the No. 1 pin PCKP of the power chip U1 is connected with the external battery V18650, the No. 6 pin BYPS of the power chip U1 is connected with the battery ground wire BGND, and the No. 2 pin of the power chip U1 is connected with the ground wire GND.

9. A rechargeable battery management system according to claim 1, wherein: It also includes a resistor R11, which is connected between the external battery V18650 and the No. 1 pin PCKP of the power chip U1; and a capacitor C10, which is connected between the No. 6 pin BYPS of the power chip U1 and the battery ground wire BGND.

10. A rechargeable battery management system according to claim 1, wherein: The power management chip U2 is a SY6978 chip.

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