Negative rapid charging circuit of battery charger

Abstract

The invention relates to the technical field of battery charging, and provides a negative quick charging circuit of a battery charger, which comprises an input module, an MCCI charge control module, a constant-current constant-voltage module, an over-temperature protection module and a negative control module. The positive electrode of the direct-current output end of the input module is connected with the power input end of the MCCI charge control module, and the negative electrode is grounded. The driving output end of the MCCI charge control module is connected with the current input end of the constant-current constant-voltage module, the charging output end of the constant-current constant-voltage module is connected with the positive electrode of the battery, and the negative electrode of the battery is grounded. The temperature detection end of the over-temperature protection module is attached to the surface of the battery through a thermistor RT1, and the control output end of the over-temperature protection module is connected with an enabling pin of the MCCI charge control module. The PWM signal output end of the negative control module is connected with the PWM input pin of the MCCI charge control module, and the discharge control end of the negative control module is connected with the negative electrode of the battery through a discharge switch Q3, and is used for switching a charge-stop-charge mode or a charge-stop-discharge-charge mode.

Description

Technical Field

[0001] The present invention relates to the technical field of battery charging, and more specifically, the present invention relates to a negative rapid charging circuit for a battery charger. Background Art

[0002] During the charging process of lead-acid batteries, polarization occurs. The overvoltage generated by polarization hinders the increase of the charging current, slows down the battery chemical reaction rate, and at the same time intensifies the hydrolysis process, generating a large amount of gas and heat, resulting in plate corrosion, electrolyte temperature rise, and even causing plate deformation and damage. Traditional charging methods usually use a small constant current to charge to 90% of the rated voltage, and then perform constant voltage charging and trickle charging. The charging time is long and the efficiency is low. Due to the existence of polarization, large current rapid charging is difficult to achieve, which limits the charging speed and the service life of the battery.

[0003] In the process of implementing the embodiments of the present invention, the inventors found that there are at least the following problems or defects in the prior art: The traditional charging method cannot effectively eliminate the polarization phenomenon, resulting in slow charging speed, increased battery temperature, shortened life, and the inability to achieve large current rapid charging. Summary of the Invention

[0004] The present invention provides a negative rapid charging circuit for a battery charger, including:

[0005] An input module, an MCCI charge control module, a constant current and constant voltage module, an over-temperature protection module, and a negative control module;

[0006] The positive pole of the DC output end of the input module is connected to the power input end of the MCCI charge control module, and the negative pole of its DC output end is grounded;

[0007] The drive output end of the MCCI charge control module is connected to the current input end of the constant current and constant voltage module, and the charging output end of the constant current and constant voltage module is connected to the positive pole of the battery, and the negative pole of the battery is grounded;

[0008] The temperature detection end of the over-temperature protection module is attached to the battery surface through a thermistor RT1, and its control output end is connected to the enable pin of the MCCI charge control module;

[0009] The PWM signal output end of the negative control module is connected to the PWM input pin of the MCCI charge control module, and its discharge control end is connected to the negative pole of the battery through a discharge switch Q3, and is used to switch the charge-stop-charge or charge-stop-discharge-charge mode according to a preset timing sequence.

[0010] Further, the input module includes a rectifier bridge, a filter capacitor C1, and a voltage regulator chip U1;

[0011] The AC input terminal of the rectifier bridge is connected to an external AC power supply. The positive pole of its DC output terminal is sequentially connected to the positive pole of the filter capacitor C1 and the input pin of the voltage regulator chip U1, and the negative pole of the DC output terminal is connected to the negative pole of the filter capacitor C1 and the ground pin of the voltage regulator chip U1;

[0012] The output pin of the voltage regulator chip U1 serves as the power output terminal of the input module, and the output voltage is 12V.

[0013] Furthermore, the MCCI charge control module includes a control chip U2, a driving MOS transistor Q1, a current sampling resistor R1, and a compensation network R2, C2;

[0014] The PWM input pin of the control chip U2 is connected to the PWM signal output terminal of the passivation control module, and its driving pin is connected to the gate of the driving MOS transistor Q1 through a resistor R10;

[0015] The drain of the driving MOS transistor Q1 is connected to the current input terminal of the constant current and constant voltage module, the source is grounded through the current sampling resistor R1, and a protection resistor R11 is connected in parallel between the gate and the source;

[0016] The current detection pin of the control chip U2 is connected to the source end of the current sampling resistor R1, and its compensation pin is grounded through a series resistor R2 and a capacitor C2 to form an RC compensation network;

[0017] The reference voltage pin of the control chip U2 outputs a 5V reference voltage to the reference voltage source U4 of the constant current and constant voltage module.

[0018] Furthermore, the model of the control chip U2 is UC3845. Its power pin is connected to the power output terminal of the input module, and the frequency setting pin is grounded through a timing resistor R12 and a timing capacitor C3 to set the PWM frequency.

[0019] Furthermore, the constant current and constant voltage module includes a constant current control unit and a constant voltage control unit;

[0020] The constant current control unit consists of an operational amplifier U3A, voltage dividing resistors R3, R4, and a feedback resistor R5:

[0021] The non-inverting input terminal of the operational amplifier U3A is grounded through voltage dividing resistors R3, R4. The resistance value of the voltage dividing resistor R3 is 1kΩ, and the resistance value of R4 is 2kΩ. The inverting input terminal is connected to the driving output terminal of the MCCI charge control module;

[0022] The output terminal of the operational amplifier U3A is connected to the input terminal of the constant voltage control unit through a feedback resistor R5;

[0023] The constant voltage control unit consists of an operational amplifier U3B, a reference voltage source U4, and a regulating transistor Q2:

[0024] The non-inverting input terminal of operational amplifier U3B is connected to the output terminal of reference voltage source U4, and the inverting input terminal is connected to the positive pole of the battery through resistor R6;

[0025] The output terminal of operational amplifier U3B is connected to the base of regulating transistor Q2 through current-limiting resistor R13. The emitter of regulating transistor Q2 is connected to the output terminal of the constant current control unit, and the collector is connected to the positive pole of the battery through current-limiting resistor R7.

[0026] Further, the regulating transistor Q2 is a PNP type triode, and a resistor R14 is connected in parallel between its base and emitter to stabilize the operating point. The value of the current-limiting resistor R7 is 0.1Ω.

[0027] Further, the over-temperature protection module includes a thermistor RT1, a comparator U5 and a relay K1;

[0028] One end of the thermistor RT1 is grounded, and the other end is connected to the non-inverting input terminal of the comparator U5 through a voltage-dividing resistor R8;

[0029] The inverting input terminal of the comparator U5 is connected to the reference voltage VREF through a voltage-dividing resistor R9. Its output terminal is connected to one end of the coil of the relay K1 through a pull-up resistor R15, and the other end of the coil is grounded;

[0030] The normally-closed contact of the relay K1 is connected in series between the power input terminal of the MCCI charge control module and the power output terminal of the input module. When the battery temperature exceeds the limit, the contact is disconnected to cut off the power supply.

[0031] Further, the model of the comparator U5 is LM393. Its power supply pin is connected to the power output terminal of the input module, and the grounding pin is grounded.

[0032] Further, the passivation control module includes a microcontroller U6, a discharge switch Q3, a discharge resistor R16 and a voltage sampling circuit R17, R18;

[0033] The PWM output pin of the microcontroller U6 is connected to the PWM input pin of the MCCI charge control module, and its discharge control pin is connected to the gate of the discharge switch Q3 through a resistor R19;

[0034] The drain of the discharge switch Q3 is connected to one end of the discharge resistor R16, the source is grounded, and the other end of the discharge resistor R16 is connected to the negative pole of the battery;

[0035] The voltage sampling circuit is composed of voltage-dividing resistors R17, R18, and is connected from the positive pole of the battery to the ADC pin of the microcontroller U6 to monitor the battery voltage in real time.

[0036] Further, the model of the microcontroller U6 is STM32F103C8T6. Its built-in ADC module collects battery voltage and temperature signals at a frequency of 100 Hz, and dynamically adjusts the PWM duty cycle through the PID algorithm to make the charging current controllable within the range of 0 - 5A.

[0037] According to the above embodiments of the present invention, it has at least the following beneficial effects: The present invention realizes the switching of charging modes of charge-stop-charge or charge-stop-discharge-charge through the passivation control module, which can effectively eliminate the polarization phenomenon generated during the charging process of lead-acid batteries. This mode can improve the charging efficiency, shorten the charging time, and at the same time avoid the long waiting time in the traditional trickle charging stage, meeting the demand for fast charging.

[0038] In addition, this circuit can reduce the temperature rise of the battery during charging, reduce the damage to the battery plates and electrolyte caused by the heat generated by polarization, thereby prolonging the service life of the battery. Through the collaborative work of the over-temperature protection module and the constant current and constant voltage module, the safety and stability of the charging process can be ensured, avoiding battery damage caused by excessive temperature or current fluctuations, and improving the overall charging performance. Brief Description of the Drawings

[0039] By referring to the following detailed description with reference to the drawings, the above and other objects, features, and advantages of the exemplary embodiments of the present invention will become easily understandable. In the drawings, several embodiments of the present invention are shown in an exemplary rather than restrictive manner, where:

[0040] Figure 1 It is a schematic diagram of the modules of the passivation fast charging circuit of the battery charger provided by an embodiment of the present invention;

[0041] Figure 2 It is a schematic diagram of the structure of the passivation fast charging circuit of the battery charger provided by an embodiment of the present invention. Detailed Embodiments

[0042] Next, the principles and spirits of the present invention will be described with reference to several exemplary embodiments. It should be understood that these embodiments are given only to enable those skilled in the art to better understand and then implement the present invention, rather than limiting the scope of the present invention in any way. On the contrary, these embodiments are provided to make the present invention more thorough and complete, and to be able to convey the scope of the present invention completely to those skilled in the art.

[0043] Those skilled in the art know that the embodiments of the present invention can be implemented as a system, device, equipment, method, or computer program product. Therefore, the present invention can be specifically implemented in the following forms: completely hardware, completely software (including firmware, resident software, microcode, etc.), or a combination of hardware and software.

[0044] It should be noted that the number of any elements in the drawings is for illustration rather than limitation, and any naming is only for distinction and does not have any restrictive meaning.

[0045] Reference is made below to Figure 1 , Figure 1 which is a schematic structural diagram of the depolarization fast charging circuit of a battery charger provided by an embodiment of the present invention. As Figure 1 shown, a depolarization fast charging circuit of a battery charger includes:

[0046] an input module, an MCCI charge control module, a constant current and constant voltage module, an over-temperature protection module, and a depolarization control module;

[0047] The positive pole of the DC output end of the input module is connected to the power input end of the MCCI charge control module, and the negative pole of its DC output end is grounded;

[0048] The drive output end of the MCCI charge control module is connected to the current input end of the constant current and constant voltage module, and the charging output end of the constant current and constant voltage module is connected to the positive pole of the battery, and the negative pole of the battery is grounded;

[0049] The temperature detection end of the over-temperature protection module is attached to the surface of the battery through a thermistor RT1, and its control output end is connected to the enable pin of the MCCI charge control module;

[0050] The PWM signal output end of the depolarization control module is connected to the PWM input pin of the MCCI charge control module, and its discharge control end is connected to the negative pole of the battery through a discharge switch Q3, and is used to switch the charge-stop-charge or charge-stop-discharge-charge mode according to a preset timing sequence.

[0051] It should be noted that this charging circuit includes an input module, an MCCI charge control module, a constant current and constant voltage module, an over-temperature protection module, and a depolarization control module. The input module is responsible for converting the external AC power supply into direct current. The MCCI charge control module is used to adjust the charging current and voltage. The constant current and constant voltage module ensures the stability of the current and voltage during the charging process. The over-temperature protection module prevents overheating by detecting the battery temperature. The depolarization control module eliminates the battery polarization phenomenon by controlling the switching of charging and discharging.

[0052] Specifically, the input module converts alternating current into direct current through a rectifier bridge, and outputs a stable 12V DC voltage after passing through a filter capacitor and a voltage regulator chip. The MCCI charge control module regulates the charging current through a control chip and a driving MOS transistor. The current sampling resistor is used to detect the current magnitude, and the compensation network is used to stabilize the control signal. The constant current and constant voltage module consists of an operational amplifier and a regulating transistor to ensure that the charging current and voltage are within the set range. The over-temperature protection module detects the battery temperature through a thermistor. When the temperature exceeds the set value, the relay cuts off the power supply to prevent the battery from overheating. The negative activation control module generates a PWM signal through a microcontroller to control the switching mode of charging and discharging.

[0053] Preferably, the voltage regulator chip of the input module can select a common 12V voltage regulator device to ensure the stability of the output voltage. The control chip of the MCCI charge control module can adopt the UC3845 model, and set the PWM frequency through timing resistors and capacitors to ensure the precise control of the charging current. The regulating transistor of the constant current and constant voltage module can select a PNP type triode, and a resistor is connected in parallel between the base and the emitter to stabilize the operating point. The comparator of the over-temperature protection module can select the LM393 model to ensure the accuracy of temperature detection. The microcontroller of the negative activation control module can select the STM32F103C8T6 model, which has an internal ADC module to collect the battery voltage and temperature signals at a frequency of 100Hz, and dynamically adjusts the PWM duty cycle through the PID algorithm to achieve precise control of the charging current.

[0054] As Figure 2 shown. The input module includes a rectifier bridge, a filter capacitor C1, and a voltage regulator chip U1;

[0055] The AC input terminal of the rectifier bridge is connected to an external AC power supply, and the positive pole of its DC output terminal is sequentially connected to the positive pole of the filter capacitor C1 and the input pin of the voltage regulator chip U1, and the negative pole of the DC output terminal is connected to the negative pole of the filter capacitor C1 and the ground pin of the voltage regulator chip U1;

[0056] The output pin of the voltage regulator chip U1 serves as the power output terminal of the input module, and the output voltage is 12V.

[0057] It should be noted that the input module includes a rectifier bridge, a filter capacitor, and a voltage regulator chip. The rectifier bridge is used to convert the external AC power supply into direct current, the filter capacitor is used to smooth the rectified DC voltage, and the voltage regulator chip is used to stabilize the voltage at 12V to ensure the normal operation of the subsequent circuit. The design of the input module can ensure that the charger outputs a stable DC voltage when connected to AC power supplies with different voltages.

[0058] Specifically, the AC input terminal of the rectifier bridge is connected to an external AC power supply. The positive pole of the DC output terminal is sequentially connected to the positive pole of the filter capacitor and the input pin of the voltage regulator chip, and the negative pole is connected to the negative pole of the filter capacitor and the ground pin of the voltage regulator chip. The capacitance of the filter capacitor can be selected according to the fluctuation range of the input voltage. Usually, a capacitor with a relatively large capacitance is selected to effectively filter out voltage fluctuations. The output pin of the voltage regulator chip serves as the power output terminal of the input module, and the output voltage is 12V to ensure stable power supply for the subsequent modules.

[0059] Preferably, the rectifier bridge can be a common full-bridge rectifier circuit, suitable for a variety of AC input voltages. The capacitance of the filter capacitor can be selected according to the actual application scenario, usually between a few hundred microfarads and several thousand microfarads, to ensure sufficient filtering effect. The voltage regulator chip can be a common 12V voltage regulator device, such as LM7812, to ensure the stability of the output voltage. In addition, an overvoltage protection circuit can be added to the input module to prevent damage to the subsequent circuit when the input voltage is too high.

[0060] In some embodiments, the MCCI charge control module includes a control chip U2, a driving MOS transistor Q1, a current sampling resistor R1, and a compensation network R2, C2;

[0061] The PWM input pin of the control chip U2 is connected to the PWM signal output terminal of the negative feedback control module, and its driving pin is connected to the gate of the driving MOS transistor Q1 through a resistor R10;

[0062] The drain of the driving MOS transistor Q1 is connected to the current input terminal of the constant current and constant voltage module, the source is grounded through the current sampling resistor R1, and a protection resistor R11 is connected in parallel between the gate and the source;

[0063] The current detection pin of the control chip U2 is connected to the source end of the current sampling resistor R1, and its compensation pin is grounded through a series resistor R2 and a capacitor C2 to form an RC compensation network;

[0064] The reference voltage pin of the control chip U2 outputs a 5V reference voltage to the reference voltage source U4 of the constant current and constant voltage module.

[0065] It should be noted that the MCCI charge control module includes a control chip, a driving MOS transistor, a current sampling resistor, and a compensation network. The control chip is used to generate a PWM signal, the driving MOS transistor is used to regulate the charging current, the current sampling resistor is used to detect the current magnitude, and the compensation network is used to stabilize the control signal to ensure precise control of the charging process. The design of this module can effectively regulate the charging current and avoid damage to the battery due to excessive or insufficient current.

[0066] Specifically, the PWM input pin of the control chip is connected to the PWM signal output terminal of the negative control module, and the drive pin is connected to the gate of the drive MOS transistor through a resistor. The drain of the drive MOS transistor is connected to the current input terminal of the constant current and constant voltage module, the source is grounded through a current sampling resistor, and a protection resistor is connected in parallel between the gate and the source to prevent excessive voltage. The current detection pin of the control chip is connected to the source end of the current sampling resistor, and the compensation pin is grounded through a series resistor and capacitor to form an RC compensation network for stabilizing the control signal. The reference voltage pin of the control chip outputs a 5V reference voltage for use by the constant current and constant voltage module.

[0067] Preferably, the control chip can be of the UC3845 model. Its power supply pin is connected to the power output terminal of the input module, and the frequency setting pin is grounded through a timing resistor and capacitor to set the PWM frequency. The drive MOS transistor can be a common N-channel MOS transistor to ensure sufficient current-carrying capacity. The resistance value of the current sampling resistor can be selected according to the magnitude of the charging current, usually in the milliohm level, to ensure the accuracy of current detection. The resistance and capacitance values of the compensation network can be selected according to the requirements of the control chip to ensure the stability of the control signal. In addition, the control chip can also be added with an overcurrent protection function to prevent damage to the circuit when the current is too large.

[0068] In some embodiments, the model of the control chip U2 is UC3845. Its power supply pin is connected to the power output terminal of the input module, and the frequency setting pin is grounded through the timing resistor R12 and the timing capacitor C3 to set the PWM frequency.

[0069] It should be noted that the model of the control chip is UC3845. Its power supply pin is connected to the power output terminal of the input module, and the frequency setting pin is grounded through a timing resistor and a timing capacitor to set the PWM frequency. UC3845 is a commonly used PWM control chip that can generate a stable PWM signal for regulating the charging current and voltage. The frequency setting pin can flexibly adjust the frequency of the PWM signal through the combination of external resistors and capacitors to adapt to different charging requirements.

[0070] Specifically, the power supply pin of the control chip is connected to the 12V output terminal of the input module to ensure the normal operation of the chip. The frequency setting pin is grounded through a timing resistor and a timing capacitor. The resistance value of the timing resistor and the capacitance value of the timing capacitor jointly determine the frequency of the PWM signal. The resistance value of the timing resistor is usually between several thousand ohms and several tens of thousand ohms, and the capacitance value of the timing capacitor is usually between several hundred picofarads and several nanofarads. The specific values can be calculated and selected according to the required PWM frequency.

[0071] Preferably, a timing resistor of 10 kΩ can be selected, and a timing capacitor of 1 nF can be selected. In this way, the PWM frequency can be set in the range of dozens of kilohertz, which is suitable for most charging scenarios. In addition, the control chip can also add an external protection circuit, such as overvoltage protection and overcurrent protection, to prevent the chip from being damaged under abnormal conditions. The frequency setting pin can also be connected to a variable resistor to flexibly adjust the PWM frequency in actual applications to adapt to different battery types and charging requirements.

[0072] In some embodiments, the constant current and constant voltage module includes a constant current control unit and a constant voltage control unit;

[0073] The constant current control unit is composed of an operational amplifier U3A, voltage dividing resistors R3, R4, and a feedback resistor R5:

[0074] The non-inverting input terminal of the operational amplifier U3A is grounded through the voltage dividing resistors R3 and R4. The resistance value of the voltage dividing resistor R3 is 1 kΩ, and the resistance value of R4 is 2 kΩ. The inverting input terminal is connected to the drive output terminal of the MCCI charge control module;

[0075] The output terminal of the operational amplifier U3A is connected to the input terminal of the constant voltage control unit through the feedback resistor R5;

[0076] The constant voltage control unit is composed of an operational amplifier U3B, a reference voltage source U4, and an adjustment transistor Q2:

[0077] The non-inverting input terminal of the operational amplifier U3B is connected to the output terminal of the reference voltage source U4, and the inverting input terminal is connected to the positive electrode of the battery through the resistor R6;

[0078] The output terminal of the operational amplifier U3B is connected to the base of the adjustment transistor Q2 through the current limiting resistor R13. The emitter of the adjustment transistor Q2 is connected to the output terminal of the constant current control unit, and the collector is connected to the positive electrode of the battery through the current limiting resistor R7.

[0079] It should be noted that the constant current and constant voltage module includes a constant current control unit and a constant voltage control unit. The constant current control unit is used to keep the current constant at the initial stage of charging to ensure that the battery can be quickly charged; the constant voltage control unit is used to keep the voltage constant at the later stage of charging to prevent the battery from being overcharged. The constant current control unit is composed of an operational amplifier, voltage dividing resistors, and a feedback resistor, and the constant voltage control unit is composed of an operational amplifier, a reference voltage source, and an adjustment transistor. The design of this module can ensure the safety and stability of the charging process.

[0080] Specifically, the operational amplifier of the constant current control unit is grounded through voltage dividing resistors with resistance values of 1 kΩ and 2 kΩ respectively, which are used to set the reference voltage for constant current control. The inverting input terminal of the operational amplifier is connected to the drive output terminal of the MCCI charge control module, and the output terminal is connected to the input terminal of the constant voltage control unit through a feedback resistor. The operational amplifier of the constant voltage control unit is connected to a reference voltage source that outputs a stable reference voltage. The inverting input terminal of the operational amplifier is connected to the positive terminal of the battery through a resistor, and the output terminal is connected to the base of the regulating transistor through a current limiting resistor. The emitter of the regulating transistor is connected to the output terminal of the constant current control unit, and the collector is connected to the positive terminal of the battery through a current limiting resistor.

[0081] Preferably, the operational amplifier of the constant current control unit can be a common general-purpose operational amplifier, such as LM358, to ensure the accuracy of current control. The resistance value of the voltage dividing resistors can be adjusted according to the magnitude of the charging current, and the resistance value of the feedback resistor can be selected according to the gain requirement of the operational amplifier. The reference voltage source of the constant voltage control unit can be TL431, which outputs a stable reference voltage. The regulating transistor can be a PNP type triode, and a resistor is connected in parallel between the base and the emitter to stabilize the operating point. The resistance value of the current limiting resistor can be selected according to the magnitude of the charging current, usually between a few ohms and dozens of ohms, to ensure the safety of the charging process.

[0082] In some embodiments, the regulating transistor Q2 is a PNP type triode, and a resistor R14 is connected in parallel between its base and emitter to stabilize the operating point, and the resistance value of the current limiting resistor R7 is 0.1 Ω.

[0083] It should be noted that the regulating transistor is a PNP type triode, a resistor is connected in parallel between its base and emitter to stabilize the operating point, and the resistance value of the current limiting resistor is 0.1 Ω. The PNP type triode is used to adjust the charging voltage in the constant voltage control unit to ensure the stability of the battery voltage in the later stage of charging and avoid overcharging. The resistor connected in parallel between the base and emitter is used to stabilize the operating point of the triode to prevent current instability caused by voltage fluctuations, and the current limiting resistor is used to limit the charging current to ensure the safety of the charging process.

[0084] Specifically, the base of the regulating transistor is connected to the output terminal of the operational amplifier of the constant voltage control unit, the emitter is connected to the output terminal of the constant current control unit, and the collector is connected to the positive terminal of the battery through a current limiting resistor. The resistance value of the resistor connected in parallel between the base and emitter is usually between a few thousand ohms and dozens of thousand ohms, which is used to stabilize the operating point of the triode. The resistance value of the current limiting resistor is 0.1 Ω, which can effectively limit the charging current and prevent battery damage caused by excessive current. The operating state of the regulating transistor is controlled by the output signal of the operational amplifier to ensure the stability of the charging voltage.

[0085] Preferably, a common PNP type triode, such as 2N3906, can be selected as the adjustment tube to ensure sufficient current-carrying capacity. A 10kΩ resistor can be selected for the resistor connected in parallel between the base and the emitter to stabilize the operating point of the triode. The resistance value of the current-limiting resistor can be adjusted according to the magnitude of the charging current, usually around 0.1Ω, to ensure the safety of the charging process. In addition, a heat sink can be added to the adjustment tube to prevent overheating and damage during high-current operation. The power of the current-limiting resistor should be selected according to the actual charging current to ensure that it can withstand the corresponding power loss.

[0086] In some embodiments, the over-temperature protection module includes a thermistor RT1, a comparator U5, and a relay K1;

[0087] One end of the thermistor RT1 is grounded, and the other end is connected to the non-inverting input terminal of the comparator U5 through a voltage-dividing resistor R8;

[0088] The inverting input terminal of the comparator U5 is connected to the reference voltage VREF through a voltage-dividing resistor R9, and its output terminal is connected to one end of the coil of the relay K1 through a pull-up resistor R15, and the other end of the coil is grounded;

[0089] The normally closed contact of the relay K1 is connected in series between the power input terminal of the MCCI charge control module and the power output terminal of the input module, and the contact is disconnected to cut off the power supply when the battery temperature exceeds the limit.

[0090] It should be noted that the over-temperature protection module includes a thermistor, a comparator, and a relay. The thermistor is used to detect the battery temperature, the comparator is used to compare the detected temperature signal with the reference voltage, and the relay is used to cut off the power supply when the temperature exceeds the set value to prevent the battery from being damaged by overheating. The design of this module can effectively prevent the battery from being damaged due to excessive temperature during the charging process and ensure the safety of the charging process.

[0091] Specifically, one end of the thermistor is grounded, and the other end is connected to the non-inverting input terminal of the comparator through a voltage-dividing resistor. The inverting input terminal of the comparator is connected to the reference voltage through a voltage-dividing resistor, and the output terminal is connected to one end of the coil of the relay through a pull-up resistor, and the other end of the coil is grounded. The normally closed contact of the relay is connected in series between the power input terminal of the MCCI charge control module and the power output terminal of the input module. When the battery temperature exceeds the set value, the comparator outputs a high level, the relay coil is energized, and the normally closed contact is disconnected to cut off the power supply.

[0092] Preferably, a thermistor can be selected as a common negative temperature coefficient thermistor (NTC), whose resistance decreases as the temperature increases, and can accurately reflect the battery temperature. The comparator can be selected as the LM393 model to ensure the accuracy of temperature comparison. The reference voltage can be provided by a voltage regulator chip to ensure the stability of the comparator. The coil voltage of the relay should match the output voltage of the input module, usually 12V, to ensure the normal operation of the relay. In addition, the over-temperature protection module can also add a temperature display function to display the battery temperature in real time through an LED or a digital tube, which is convenient for users to monitor the charging status.

[0093] In some embodiments, the comparator U5 is of the LM393 model, and its power supply pin is connected to the power output terminal of the input module, and the ground pin is grounded.

[0094] It should be noted that the comparator is of the LM393 model, and its power supply pin is connected to the 12V output terminal of the input module, and the ground pin is grounded. LM393 is a commonly used dual-channel comparator that can compare the input signal with the reference voltage and output a high-level or low-level signal. The power supply pin is connected to the 12V output terminal of the input module to ensure the normal operation of the comparator, and the ground pin is grounded to form a complete circuit loop. This comparator is used in the over-temperature protection module to ensure that the power supply can be cut off in time when the battery temperature exceeds the set value.

[0095] Specifically, the power supply pin of the comparator is connected to the 12V output terminal of the input module, and the ground pin is grounded. The non-inverting input terminal is connected to the thermistor through a voltage-dividing resistor to receive the temperature detection signal; the inverting input terminal is connected to the reference voltage through a voltage-dividing resistor to set the threshold of temperature protection. The output terminal is connected to one end of the relay coil through a pull-up resistor. When the temperature exceeds the set value, the comparator outputs a high level, the relay coil is energized, and the normally closed contact is disconnected to cut off the power supply. The reference voltage can be provided by a voltage regulator chip to ensure the stability of the comparator.

[0096] Preferably, the comparator can be selected as the LM393 model to ensure the accuracy and response speed of temperature comparison. The reference voltage can be provided by the TL431 voltage regulator chip to output a stable reference voltage to ensure the accuracy of the temperature protection threshold. The resistance value of the pull-up resistor can be selected according to the coil current of the relay, usually between a few thousand ohms and dozens of thousand ohms, to ensure the stability of the comparator output signal. In addition, a filter capacitor can be added to the comparator to filter out the noise in the input signal and improve the accuracy of temperature detection. The coil voltage of the relay should match the output voltage of the input module, usually 12V, to ensure the normal operation of the relay.

[0097] In some embodiments, the negative feedback control module includes a microcontroller U6, a discharge switch Q3, a discharge resistor R16, and a voltage sampling circuit R17, R18;

[0098] The PWM output pin of the microcontroller U6 is connected to the PWM input pin of the MCCI charge control module, and its discharge control pin is connected to the gate of the discharge switch Q3 through the resistor R19;

[0099] The drain of the discharge switch Q3 is connected to one end of the discharge resistor R16, the source is grounded, and the other end of the discharge resistor R16 is connected to the negative electrode of the battery;

[0100] The voltage sampling circuit is composed of voltage-dividing resistors R17 and R18, which connect the positive electrode of the battery to the ADC pin of the microcontroller U6 to monitor the battery voltage in real time.

[0101] It should be noted that the passivation control module includes a microcontroller, a discharge switch, a discharge resistor, and a voltage sampling circuit. The microcontroller is used to generate PWM signals to control the switching mode of charging and discharging; the discharge switch is used to control the discharge process of the battery; the discharge resistor is used to limit the discharge current; the voltage sampling circuit is used to monitor the battery voltage in real time. The design of this module can achieve the switching of charging modes such as charge-stop-charge or charge-stop-discharge-charge, effectively eliminate the battery polarization phenomenon, and improve the charging efficiency.

[0102] Specifically, the PWM output pin of the microcontroller is connected to the PWM input pin of the MCCI charge control module to adjust the charging current. The discharge control pin is connected to the gate of the discharge switch through a resistor to control the on and off of the discharge switch. The drain of the discharge switch is connected to one end of the discharge resistor, the source is grounded, and the other end of the discharge resistor is connected to the negative electrode of the battery to limit the discharge current. The voltage sampling circuit is composed of voltage-dividing resistors, which connect the positive electrode of the battery to the ADC pin of the microcontroller to monitor the battery voltage in real time and ensure the precise control of the charging process.

[0103] Preferably, the microcontroller can be of the STM32F103C8T6 model, with an internal ADC module to collect the battery voltage and temperature signals at a frequency of 100Hz, and dynamically adjust the PWM duty cycle through the PID algorithm to make the charging current controllable within the range of 0 - 5A. The discharge switch can be an N-channel MOS tube to ensure sufficient current-carrying capacity. The resistance value of the discharge resistor can be selected according to the magnitude of the discharge current, usually between a few ohms and dozens of ohms, to ensure the safety of the discharge process. The resistance values of the voltage-dividing resistors in the voltage sampling circuit can be selected according to the range of the battery voltage to ensure that the voltage input to the ADC pin is within the allowable range of the microcontroller. In addition, the microcontroller can also be equipped with communication interfaces such as UART or I2C to exchange data with external devices and achieve remote monitoring and control of the charging process.

[0104] In some embodiments, the microcontroller U6 is of the model STM32F103C8T6. Its built-in ADC module collects battery voltage and temperature signals at a frequency of 100Hz, and dynamically adjusts the PWM duty cycle through the PID algorithm to make the charging current controllable within the range of 0 - 5A.

[0105] It should be noted that the microcontroller is of the model STM32F103C8T6. Its built-in ADC module collects battery voltage and temperature signals at a frequency of 100Hz, and dynamically adjusts the PWM duty cycle through the PID algorithm to make the charging current controllable within the range of 0 - 5A. STM32F103C8T6 is a commonly used microcontroller with an ARM Cortex-M3 core, featuring high performance and low power consumption. The built-in ADC module can collect battery voltage and temperature signals in real time, and the PID algorithm is used to precisely control the charging current to ensure the stability and efficiency of the charging process.

[0106] Specifically, the ADC pin of the microcontroller is connected to the positive pole of the battery through a voltage sampling circuit to collect the battery voltage signal in real time. The temperature signal can be obtained through a thermistor or other temperature sensors and input into the ADC pin of the microcontroller. The microcontroller calculates the appropriate PWM duty cycle through the PID algorithm based on the collected voltage and temperature signals, and outputs it to the PWM input pin of the MCCI charge control module to adjust the charging current. The parameters of the PID algorithm can be set according to the characteristics of the battery and the charging requirements to ensure that the charging current is precisely controllable within the range of 0 - 5A.

[0107] Preferably, the microcontroller can be selected as the STM32F103C8T6 model to ensure sufficient processing power and ADC sampling accuracy. The resistance value of the voltage dividing resistor in the voltage sampling circuit can be selected according to the range of the battery voltage to ensure that the voltage input to the ADC pin is within the allowable range of the microcontroller. The parameters of the PID algorithm can be adjusted according to the actual charging requirements, usually including the proportional coefficient, integral time, and differential time, to ensure the fast response and stability of the charging current. In addition, the microcontroller can also be equipped with communication interfaces such as UART or I2C to facilitate data exchange with external devices and achieve remote monitoring and control of the charging process. The temperature sensor can be selected as a common NTC thermistor or digital temperature sensor to ensure the accuracy of temperature detection.

[0108] The above embodiments of the present invention have the following beneficial effects: The present invention realizes the switching of charging modes such as charge-stop-charge or charge-stop-discharge-charge through a passivation control module, which can effectively eliminate the polarization phenomenon generated during the charging process of lead-acid batteries. This mode can improve the charging efficiency, shorten the charging time, and at the same time avoid the long waiting time in the traditional trickle charging stage, meeting the requirements of fast charging. In addition, this circuit can reduce the temperature rise of the battery during charging, reduce the damage to the battery plates and electrolyte caused by the heat generated by polarization, thereby extending the service life of the battery.

[0109] Through the collaborative work of the overtemperature protection module and the constant current and constant voltage module, the safety and stability of the charging process can be ensured, avoiding battery damage caused by excessive temperature or current fluctuations, and improving the overall charging performance. The MCCI charge control module can precisely adjust the charging current and voltage, and dynamically adjust the PWM duty cycle in combination with the PID algorithm of the microcontroller, making the charging current controllable within the range of 0-5A, further optimizing the charging effect. The overall circuit design can take into account both fast charging and battery protection, and is suitable for scenarios such as electric vehicles that require efficient charging.

[0110] Furthermore, the storage medium of the implementation manner of the present application stores program instructions that can implement all of the above methods. Among them, the program instructions can be stored in the above storage medium in the form of a software product, including several instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) or a processor to execute all or part of the steps of the methods described in the various implementation manners of the present application. The foregoing storage medium includes: various media that can store program codes such as USB flash drives, mobile hard disks, read-only memories (ROMs), random access memories (RAMs), magnetic disks, or optical discs, or terminal devices such as computers, servers, mobile phones, and tablets.

[0111] The above description is only some preferred embodiments of the present invention and an explanation of the applied technical principles. Those skilled in the art should understand that the scope of the invention involved in the embodiments of the present invention is not limited to the technical solutions formed by the specific combination of the above technical features, and should also cover other technical solutions formed by any combination of the above technical features or their equivalent features without departing from the above inventive concept. For example, the technical solutions formed by mutually replacing the above features with the (but not limited to) technical features with similar functions disclosed in the embodiments of the present invention.

Claims

1. A negative quick charging circuit for a battery charger, characterized in that, It includes: an input module, an MCCI charge control module, a constant current and constant voltage module, an over-temperature protection module, and a passivation control module; The positive pole of the DC output end of the input module is connected to the power input end of the MCCI charge control module, and the negative pole of its DC output end is grounded; The drive output end of the MCCI charge control module is connected to the current input end of the constant current and constant voltage module, and the charging output end of the constant current and constant voltage module is connected to the positive pole of the battery, and the negative pole of the battery is grounded; The temperature detection end of the over-temperature protection module is attached to the surface of the battery through a thermistor RT1, and its control output end is connected to the enable pin of the MCCI charge control module; The PWM signal output end of the passivation control module is connected to the PWM input pin of the MCCI charge control module, and its discharge control end is connected to the negative pole of the battery through a discharge switch Q3, and is used to switch between the "charge-stop-charge" or "charge-stop-discharge-charge" modes according to a preset timing sequence.

2. The circuit according to claim 1, characterized in that The input module includes a rectifier bridge, a filter capacitor C1, and a voltage regulator chip U1; The AC input end of the rectifier bridge is connected to an external AC power supply, the positive pole of its DC output end is sequentially connected to the positive pole of the filter capacitor C1 and the input pin of the voltage regulator chip U1, and the negative pole of the DC output end is connected to the negative pole of the filter capacitor C1 and the ground pin of the voltage regulator chip U1; The output pin of the voltage regulator chip U1 serves as the power output end of the input module, and the output voltage is 12V.

3. The circuit according to claim 1, wherein The MCCI charge control module includes a control chip U2, a drive MOS tube Q1, a current sampling resistor R1, and a compensation network R2, C2; The PWM input pin of the control chip U2 is connected to the PWM signal output end of the passivation control module, and its drive pin is connected to the gate of the drive MOS tube Q1 through a resistor R10; The drain of the drive MOS tube Q1 is connected to the current input end of the constant current and constant voltage module, the source is grounded through the current sampling resistor R1, and a protection resistor R11 is connected in parallel between the gate and the source; The current detection pin of the control chip U2 is connected to the source end of the current sampling resistor R1, and its compensation pin is grounded through a series resistor R2 and a capacitor C2 to form an RC compensation network; The reference voltage pin of the control chip U2 outputs a 5V reference voltage to the reference voltage source U4 of the constant current and constant voltage module.

4. The circuit according to claim 3, characterized in that, The model of the control chip U2 is UC3845, its power pin is connected to the power output end of the input module, and the frequency setting pin is grounded through a timing resistor R12 and a timing capacitor C3 to set the PWM frequency.

5. The circuit according to claim 1, wherein The constant current and constant voltage module includes a constant current control unit and a constant voltage control unit; The constant current control unit consists of an operational amplifier U3A, voltage dividing resistors R3, R4, and a feedback resistor R5: The non-inverting input end of the operational amplifier U3A is grounded through the voltage dividing resistors R3, R4. The resistance value of the voltage dividing resistor R3 is 1kΩ, the resistance value of R4 is 2kΩ, and the inverting input end is connected to the drive output end of the MCCI charge control module; The output end of the operational amplifier U3A is connected to the input end of the constant voltage control unit through the feedback resistor R5; The constant voltage control unit consists of an operational amplifier U3B, a reference voltage source U4, and a regulating transistor Q2: The non-inverting input terminal of the operational amplifier U3B is connected to the output terminal of the reference voltage source U4, and the inverting input terminal is connected to the positive pole of the battery through the resistor R6; The output terminal of the operational amplifier U3B is connected to the base of the regulating transistor Q2 through the current-limiting resistor R13. The emitter of the regulating transistor Q2 is connected to the output terminal of the constant current control unit, and the collector is connected to the positive pole of the battery through the current-limiting resistor R7.

6. The circuit according to claim 5, wherein The regulating transistor Q2 is a PNP type triode, and a resistor R14 is connected in parallel between its base and emitter to stabilize the operating point. The value of the current-limiting resistor R7 is 0.1 Ω.

7. The circuit according to claim 1, characterized in that, The over-temperature protection module includes a thermistor RT1, a comparator U5 and a relay K1; One end of the thermistor RT1 is grounded, and the other end is connected to the non-inverting input terminal of the comparator U5 through the voltage-dividing resistor R8; The inverting input terminal of the comparator U5 is connected to the reference voltage VREF through the voltage-dividing resistor R9. Its output terminal is connected to one end of the coil of the relay K1 through the pull-up resistor R15, and the other end of the coil is grounded; The normally closed contact of the relay K1 is connected in series between the power input terminal of the MCCI charge control module and the power output terminal of the input module. When the battery temperature exceeds the limit, the contact is disconnected to cut off the power supply.

8. The circuit according to claim 7, wherein The model of the comparator U5 is LM393. Its power supply pin is connected to the power output terminal of the input module, and the grounding pin is grounded.

9. The circuit according to claim 1, wherein The passivation control module includes a microcontroller U6, a discharge switch Q3, a discharge resistor R16 and a voltage sampling circuit R17, R18; The PWM output pin of the microcontroller U6 is connected to the PWM input pin of the MCCI charge control module, and its discharge control pin is connected to the gate of the discharge switch Q3 through the resistor R19; The drain of the discharge switch Q3 is connected to one end of the discharge resistor R16, the source is grounded, and the other end of the discharge resistor R16 is connected to the negative pole of the battery; The voltage sampling circuit is composed of voltage-dividing resistors R17, R18, and is connected from the positive pole of the battery to the ADC pin of the microcontroller U6 to monitor the battery voltage in real time.

10. The circuit according to claim 9, characterized in that, The model of the microcontroller U6 is STM32F103C8T6. Its built-in ADC module collects the battery voltage and temperature signals at a frequency of 100 Hz, and dynamically adjusts the PWM duty cycle through the PID algorithm to make the charging current controllable within the range of 0 - 5 A.

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