A lead-acid battery charging management system

Abstract

The present invention discloses a lead-acid battery charging management system, which includes a battery protector. The battery protector is provided with a circuit board. The circuit board is provided with a DCDC voltage conversion circuit, a charging control circuit and several temperature sensors. The DCDC voltage conversion circuit, the input filter circuit and the charging control circuit are electrically connected to each other. The charging control circuit includes a control chip, an optocoupler and a power MOS tube. The control chip is connected to the gate of the power MOS tube. The drain of the power MOS tube is connected to the negative pole of the battery pack, and the source of the power MOS tube is connected to the negative pole of the charger input line. The control chip is electrically connected to the temperature sensor. The temperature sensor is attached to the inner wall of a single cell of the battery pack with a lead wire. The control chip controls the conduction time of the power MOS tube according to the comparison between the detected temperature value of the temperature sensor and the temperature preset value so as to change the input charging current. The present invention has the advantages of real-time detecting the battery temperature, preventing the battery from bulging by adjusting the charging current, and improving the service life of the battery, etc.

Description

Technical Field

[0001] The present invention belongs to the technical field of battery charging, and particularly relates to a lead-acid battery charging management system. Background Art

[0002] Existing lead-acid battery packs of electric bicycles are directly charged after the charger is connected to the charging port, and there is no protection circuit device for the battery pack. During the charging process of the battery pack, if a failure occurs in the battery pack or the charger, it may cause the battery pack to bulge directly, or even catch fire due to overheating. Especially in the later stage of battery use, due to long-term charging and water loss of the battery pack, the charging indicator cannot turn off in the later stage of charging, resulting in overheating of the battery and then excessive water loss, and such a vicious cycle greatly shortens the service life of the battery pack. Summary of the Invention

[0003] The object of the present invention is to solve the problems in the background art, and propose a lead-acid battery charging management system, which can detect the battery temperature in real time, and prevent the battery from bulging due to excessive temperature by adjusting the charging current, and improve the service life of the battery.

[0004] To achieve the above object, the present invention proposes a lead-acid battery charging management system, including a battery protector. The battery protector is provided with a circuit board, and the circuit board is provided with a DCDC voltage conversion circuit, a charging control circuit, a charging socket, a battery socket and several temperature sensors. The DCDC voltage conversion circuit, the input filter circuit and the charging control circuit are electrically connected to each other. The DCDC voltage conversion circuit includes a DCDC voltage conversion chip and a three-terminal voltage regulator. The DCDC voltage conversion circuit converts the battery pack voltage input by the input filter circuit into a low power supply voltage and then transmits it to the charging control circuit. The charging control circuit includes a control chip, an optocoupler and a power MOS transistor. The control chip is connected to the gate of the power MOS transistor through the optocoupler. The drain of the power MOS transistor is connected to the negative electrode of the battery pack through a current sampling resistor R1, and the source of the power MOS transistor is connected to the negative electrode of the charger input line. The control chip is electrically connected to the temperature sensors, and the temperature sensors are attached to the inner wall of each single cell of the battery pack one by one with leads. The positive electrode of the input filter circuit is connected to the positive electrode of the charger output line. The charger input line and the charger output line are respectively connected to the charging socket and the battery socket. The control chip controls the conduction time of the power MOS transistor according to the detected temperature value of the temperature sensors compared with the temperature preset value to change the input charging current of the charger input line.

[0005] Preferably, a resistor R7 and a resistor R8 are connected between the control chip and the positive electrode of the battery pack. A capacitor C3 and a resistor R9 are connected in parallel on the connection line between the control chip and the resistor R7 to sample the charging voltage of the battery pack. The control chip controls the conduction time of the power MOS transistor according to the sampled value of the charging voltage compared with the voltage preset value to change the input charging current of the charger input line.

[0006] Preferably, the input filter circuit includes an input fuse FU1, an isolation diode D1, and an input filter electrolytic capacitor CD1 connected in sequence. The input fuse FU1 is connected to the positive electrode of the battery pack, and the negative electrode of the input filter electrolytic capacitor CD1 is connected to the negative electrode of the battery pack.

[0007] Preferably, the capacitance of the input filter electrolytic capacitor CD1 is 470 uF to 1000 uF.

[0008] Preferably, the DCDC voltage conversion circuit includes an energy storage transformer BT1, an output rectifier diode D3, and a filter capacitor CD3 connected in series in sequence. The energy storage transformer BT1 is connected to the DCDC voltage conversion chip and the optocoupler respectively, and the filter capacitor CD3 is connected to the three-terminal voltage regulator.

[0009] Preferably, a resistor R3 is connected between the positive electrode of the filter capacitor CD3 and the three-terminal voltage regulator.

[0010] Preferably, the battery protector includes a housing. The circuit board is installed inside the housing. The housing is provided with a charging indicator light, a temperature sensor lead hole, a battery input line hole, and a charging input line hole. The charger input line and the charger output line pass through the charging input line hole and the battery input line hole respectively and are connected to the charging socket and the battery socket. The charging indicator light is electrically connected to the control chip.

[0011] Preferably, the control chip is connected to a resistor R16. The resistor R16 is connected to the negative electrode of the battery pack through a sampling resistor R1. A capacitor C6 is connected in parallel on the connection line between the resistor R16 and the control chip.

[0012] Preferably, the model of the three-terminal voltage regulator is 78L05.

[0013] Preferably, the model of the DCDC voltage conversion chip is SD4938.

[0014] The beneficial effects of the present invention: By attaching the temperature sensor to the inner wall of the battery pack with a lead to detect the temperature of each battery in the battery pack in real time, when the temperature of one of the batteries is detected to exceed the set value, the input charging current is reduced through the charging control circuit or the charging circuit is directly turned off to stop charging until the detected temperature of the battery pack drops to the normal temperature, improving the service life of the storage battery.

[0015] The features and advantages of the present invention will be described in detail through embodiments in conjunction with the accompanying drawings. Description of the Drawings

[0016] Figure 1 It is a schematic diagram of a battery protector of an embodiment.

[0017] Figure 2 It is a disassembled schematic diagram of a battery protector of an embodiment.

[0018] Figure 3 It is a left view of a battery protector of an embodiment.

[0019] Figure 4 It is a circuit diagram of a circuit board of an embodiment.

[0020] In the figures: 1 - housing, 2 - circuit board, 11 - upper cover, 12 - base, 13 - temperature sensor lead hole, 14 - charging indicator light, 15 - battery input wire hole, 16 - charging input wire hole, 21 - temperature sensor, 22 - battery socket, 23 - charging socket. Detailed Embodiment

[0021] Refer to Figure 1 , Figure 2 , Figure 3 and Figure 4, this embodiment provides a lead-acid battery charging management system, including a battery protector. The battery protector is provided with a circuit board 2, and the circuit board 2 is provided with a DCDC voltage conversion circuit, a charging control circuit, a charging socket 23, a battery socket 22, and several temperature sensors 21. The DCDC voltage conversion circuit includes a DCDC voltage conversion chip IC1 and a three-terminal voltage regulator U1. The DCDC voltage conversion circuit converts the battery pack voltage input by the input filter circuit into a 5V power supply voltage and then transmits it to the charging control circuit. The three-terminal voltage regulator U1 is connected to the control chip U2. The charging control circuit includes a control chip U2, an optocoupler PC1, and a power MOS transistor QA1. The pin 8 of the control chip U2 is connected to the gate of the power MOS transistor QA1 through a resistor R5 and the optocoupler PC1 so as to control the charging by turning on the power MOS transistor QA1. The drain of the power MOS transistor QA1 is connected to the negative electrode of the battery pack through a current sampling resistor R1, and the source of the power MOS transistor QA1 is connected to the negative electrode of the charger input line. The control chip U2 is electrically connected to five temperature sensors. The temperature sensors 21 are attached to the inner walls of the single cells of the battery pack one by one with leads. The positive electrode of the input filter circuit is connected to the positive electrode of the charger output line. The charger input line and the charger output line are respectively connected to the charging socket 23 and the battery socket 22. The control chip U2 controls the conduction time of the power MOS transistor according to the comparison between the detected temperature value of the temperature sensor and the temperature preset value to change the input charging current of the charger input line. The input filter circuit is connected to the battery pack and the charger input line. Among them, the five temperature sensors 21 are respectively denoted as RT1 to RT5. One ends of the five temperature sensors are respectively connected to the pins 10 to 15 of the control chip U2, and the other ends of the five temperature sensors 21 are respectively connected to R10 to R15 and C7, C4, C8, C5, C9, C10 so as to be able to provide battery temperature information for U2. The pin 3 of the control chip U2 is connected to the indicator LED1 through a resistor R6 to provide an indication of the working state of the control chip U2.

[0022] A resistor R7 and a resistor R8 are connected between the control chip U2 and the positive electrode of the battery pack. A capacitor C3 and a resistor R9 are connected in parallel with the connection line between the control chip U2 and the resistor R7 to sample the charging voltage of the battery pack. The control chip U2 controls the conduction time of the power MOS transistor QA1 according to the comparison between the sampled value of the charging voltage and the voltage preset value to change the input charging current of the charger input line.

[0023] The input filter circuit includes an input fuse FU1, an isolation diode D1, and an input filter electrolytic capacitor CD1 connected in sequence. The input fuse FU1 is connected to the positive electrode of the battery pack.

[0024] The capacitance of the input filter electrolytic capacitor CD1 is 470uF to 1000uF.

[0025] The DCDC voltage conversion circuit includes an energy storage transformer BT1, an output rectifier diode D3, and a filter capacitor CD3 connected in series in sequence. The energy storage transformer BT1 is respectively connected to a DCDC voltage conversion chip IC1 and an optocoupler PC1. A three-terminal voltage regulator U1 is connected to the positive electrode of the filter capacitor CD3 through a resistor R3, and after being regulated by the three-terminal voltage regulator U1, it provides a 5V power supply voltage for the control chip U2.

[0026] The battery protector includes a housing 1. A circuit board 2 is installed inside the housing 1. The housing 1 is provided with a charging indicator light 14, a temperature sensor lead hole 13, a battery input line hole 15, and a charging input line hole 16. The charger input line and the charger output line respectively pass through the charging input line hole 16 and the battery input line hole 15 and are then connected to a charging socket 23 and a battery socket 22. The charging indicator light 14 is electrically connected to the control chip U2. The charging indicator light 14 is an indicator LED1. The housing 1 is formed by snap-connecting an upper cover 11 and a base 12. Inside the base 12, there are positioning posts for positioning and installing the circuit board 2.

[0027] The control chip U2 is connected to a resistor R16. The resistor R16 is connected to the negative electrode of the battery pack through a sampling resistor R1. A capacitor C6 is connected in parallel to the connection line between the resistor R16 and the control chip U2, which can provide current sampling for the control chip U2.

[0028] The model of the three-terminal voltage regulator U1 is 78L05, and the model of the DCDC voltage conversion chip IC1 is SD4938.

[0029] The working process of the present invention:

[0030] During the working process of this lead-acid battery charging management system, the charging output line of the charger is connected to the positive and negative electrodes of the battery pack. The charging input line of the charger is connected to the power supply. After the temperature sensor 21 is attached to the inner wall of the battery pack with a lead, the control chip U2 real-time collects the temperature of each battery in the battery pack. When it detects that the temperature of any one of the batteries exceeds the temperature preset value or the charging voltage is higher than the voltage preset value, the control chip U2 outputs a control signal and controls the conduction time of the power MOS transistor QA1 to reduce the input charging current. If the temperature continues to rise, the charging current will continue to decrease until the temperature of the battery pack drops to the normal temperature, or directly turn off the charging circuit and stop charging, so as to achieve the purpose of protecting the battery pack from thermal runaway (not being inflated).

[0031] The above embodiments are descriptions of the present invention, not limitations of the present invention. Any simple transformation of the present invention belongs to the protection scope of the present invention.

Claims

1. A lead-acid battery charging management system, including a battery protector, the battery protector is provided with a circuit board, characterized in that: The circuit board is provided with a DCDC voltage conversion circuit, a charging control circuit, a charging socket, a battery socket, and several temperature sensors. The DCDC voltage conversion circuit, the input filter circuit, and the charging control circuit are electrically connected to each other. The DCDC voltage conversion circuit includes a DCDC voltage conversion chip and a three-terminal voltage regulator. The DCDC voltage conversion circuit converts the battery pack voltage input by the input filter circuit into a low power supply voltage and then transmits it to the charging control circuit. The charging control circuit includes a control chip, an optocoupler, and a power MOS transistor. The control chip is connected to the gate of the power MOS transistor through the optocoupler. The drain of the power MOS transistor is connected to the negative electrode of the battery pack through a current sampling resistor R1, and the source of the power MOS transistor is connected to the negative electrode of the charger input line. The control chip is electrically connected to the temperature sensors. The temperature sensors are attached to the inner walls of the single cells of the battery pack one by one with leads. The positive electrode of the input filter circuit is connected to the positive electrode of the charger output line. The charger input line and the charger output line are respectively connected to the charging socket and the battery socket. The control chip controls the conduction time of the power MOS transistor according to the comparison between the detected temperature value of the temperature sensor and the temperature preset value to change the input charging current of the charger input line. A resistor R7 and a resistor R8 are connected between the control chip and the positive electrode of the battery pack. A capacitor C3 and a resistor R9 are connected in parallel on the connection line between the control chip and the resistor R7 to sample the charging voltage of the battery pack. The control chip controls the conduction time of the power MOS transistor according to the comparison between the sampled value of the charging voltage and the voltage preset value to change the input charging current of the charger input line. The control chip is connected to a resistor R16. The resistor R16 is connected to the negative electrode of the battery pack through a sampling resistor R1. A capacitor C6 is connected in parallel on the connection line between the resistor R16 and the control chip.

2. The lead-acid battery charging management system according to claim 1, wherein: The input filter circuit includes an input fuse FU1, an isolation diode D1, and an input filter electrolytic capacitor CD1 connected in sequence. The input fuse FU1 is connected to the positive electrode of the battery pack, and the negative electrode of the input filter electrolytic capacitor CD1 is connected to the negative electrode of the battery pack.

3. The lead-acid battery charging management system according to claim 2, characterized in that: The capacitance of the input filter electrolytic capacitor CD1 is 470 uF to 1000 uF.

4. The lead-acid battery charging management system according to claim 1, characterized in that: The DCDC voltage conversion circuit includes a energy storage transformer BT1, an output rectifier diode D3, and a filter capacitor CD3 connected in series in sequence. The energy storage transformer BT1 is respectively connected to the DCDC voltage conversion chip and the optocoupler. The filter capacitor CD3 is connected to the three-terminal voltage regulator.

5. The lead-acid battery charging management system according to claim 4, characterized in that: A resistor R3 is connected between the positive electrode of the filter capacitor CD3 and the three-terminal voltage regulator.

6. The lead-acid battery charging management system according to claim 1, wherein: The battery protector includes a housing. The circuit board is installed inside the housing. The housing is provided with a charging indicator light, temperature sensor lead holes, battery input line holes, and charging input line holes. The charger input line and the charger output line respectively pass through the charging input line hole and the battery input line hole and then are connected to the charging socket and the battery socket. The charging indicator light is electrically connected to the control chip.

7. The lead-acid battery charging management system according to claim 1, characterized in that: The model of the three-terminal voltage regulator is 78L05.

8. The lead-acid battery charging management system according to claim 1, characterized in that: The model of the DCDC voltage conversion chip is SD4938.

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