Battery charge and discharge management circuit

Abstract

A battery charging and discharging management circuit includes a microcontroller, a microcontroller power supply circuit, an input voltage detection circuit, an input voltage start / stop circuit, a trickle charging circuit, a constant current charging circuit, a battery charging overcurrent detection circuit, a battery charging / discharging overtemperature detection circuit, a battery voltage detection circuit, a battery discharge switch circuit, a circuit operating status indicator circuit, and a battery interface. The trickle charging circuit and the constant current charging circuit are connected in parallel. The external power input is connected to the battery interface through the parallel trickle charging circuit and the constant current charging circuit. The external power supply charges the battery through the trickle charging circuit or the constant current charging circuit. During charging, the battery voltage detection circuit feeds back the detection result to the microcontroller. The microcontroller controls the operation of the trickle charging circuit and the constant current charging circuit. During charging, the microcontroller switches between the trickle charging circuit and the constant current charging circuit according to the battery voltage and charging time to ensure that the battery can be fully charged under different ambient temperatures without overcharging.

Description

Technical Field

[0001] This utility model relates to a circuit system, and more particularly to a battery charging and discharging management circuit. Background Technology

[0002] Currently, most battery charging uses commercially available analog circuit charging management chips. These analog chips typically sample the battery voltage or charging current to control the charging and discharging cutoff. However, nickel-cadmium and nickel-metal hydride batteries exhibit different voltage profiles at different ambient temperatures. Figure 1 The charging curves of nickel-cadmium (or nickel-metal hydride) batteries described are shown at 0°C, 25°C, and 50°C. However, because the charging curves and charging cutoff voltages of nickel-cadmium (or nickel-metal hydride) batteries are inconsistent at different temperatures, it is difficult to determine whether the battery is fully charged by only sampling the battery voltage or charging current. Utility Model Content

[0003] Therefore, it is necessary to provide a battery charging and discharging management circuit to address the shortcomings of existing technologies.

[0004] A battery charging and discharging management circuit includes a microcontroller, a microcontroller power supply circuit, an input voltage detection circuit, an input voltage start / stop circuit, a trickle charging circuit, a constant current charging circuit, a battery charging overcurrent detection circuit, a battery charging / discharging overtemperature detection circuit, a battery voltage detection circuit, a battery discharging switch circuit, a circuit operating status indicator circuit, and a battery interface. The microcontroller power supply circuit, input voltage detection circuit, input voltage start / stop circuit, trickle charging circuit, constant current charging circuit, battery charging overcurrent detection circuit, battery charging / discharging overtemperature detection circuit, battery voltage detection circuit, battery discharging switch circuit, and circuit operating status indicator circuit are all connected to the microcontroller. The trickle charging circuit and the constant current charging circuit are connected in parallel. The external power input terminal is connected to the battery interface through the parallel trickle charging circuit and constant current charging circuit, and the external power supply charges the battery through the trickle charging circuit or the constant current charging circuit.

[0005] In one embodiment, the input terminals of the parallel trickle charging circuit and constant current charging circuit are the charging access terminals. The input voltage start / stop circuit is connected between the external power input terminal and the charging access terminal. The microcontroller controls the circuit's on / off state through the input voltage start / stop circuit.

[0006] In one embodiment, the battery charging / discharging over-temperature detection circuit is connected to the circuit between the microcontroller power supply circuit and the microcontroller. The battery charging / discharging over-temperature detection circuit is equipped with a thermistor NTC. The battery charging / discharging over-temperature detection circuit detects the temperature of the external battery and feeds it back to the microcontroller.

[0007] In one embodiment, the battery charging overcurrent detection circuit is connected to the battery interface. The battery charging overcurrent detection circuit is used to detect the magnitude of the current when the battery is charging and feed it back to the microcontroller.

[0008] In one embodiment, the battery voltage detection circuit is connected to the battery interface. The battery charging overcurrent detection circuit is used to detect the battery voltage during charging and discharging and feed it back to the microcontroller.

[0009] In one embodiment, the battery discharge switch circuit is connected to the battery interface and is connected to the circuit between the battery and the external load to control the on / off state of the circuit between the battery and the external load.

[0010] In one embodiment, the trickle charging circuit includes an NMOS transistor Q6 and a PMOS transistor Q3. The gate of the NMOS transistor Q6 is connected to the microcontroller through a resistor R42, the source of the NMOS transistor Q6 is grounded, the drain of the NMOS transistor Q6 is connected to the gate of the PMOS transistor Q3 through a resistor R40, the source of the PMOS transistor Q3 is connected to the output terminal of the input voltage start / stop circuit, and the drain of the PMOS transistor Q3 is connected to the battery interface.

[0011] In one embodiment, the constant current charging circuit includes transistors Q14, Q9, and Q13, several current-limiting resistors, resistor R74, and resistor R76. Transistor Q14 is an NPN transistor, while transistors Q13 and Q9 are PNP transistors. The current-limiting resistors are connected in parallel. One end of the parallel current-limiting resistor is connected to the output terminal of the input voltage start / stop circuit, and the other end is connected to the emitter of transistor Q9. The collector of transistor Q9 is connected to the battery interface, and the base of transistor Q9 is connected to the collector of transistor Q14 through resistor R74. The emitter of transistor Q14 is grounded, and the base of transistor Q14 is connected to the microcontroller through resistor R76. The emitter and base of transistor Q13 are connected in parallel to the current-limiting resistor, and the collector of transistor Q13 is connected to the base of transistor Q9.

[0012] The beneficial effects of this utility model battery charging and discharging management circuit are as follows: By setting up a microcontroller, trickle charging circuit, constant current charging circuit, battery voltage detection circuit, and battery interface, the trickle charging circuit, constant current charging circuit, and battery voltage detection circuit are all connected to the microcontroller. During charging, the battery voltage detection circuit feeds back the detection result to the microcontroller, and the microcontroller controls the operation of the trickle charging circuit and the constant current charging circuit. During charging, the microcontroller switches between the trickle charging circuit and the constant current charging circuit according to the battery voltage and charging time, ensuring that the battery can be fully charged under different ambient temperatures without overcharging, making it highly practical. Attached Figure Description

[0013] Figure 1 Voltage curves of nickel-cadmium or nickel-metal hydride batteries when charged at different ambient temperatures;

[0014] Figure 2 This is a schematic diagram showing the connection of different modules in the battery charge and discharge management circuit of this utility model.

[0015] Figure 3 This is a circuit diagram of the battery charge and discharge management circuit of this utility model. Detailed Implementation

[0016] To make the above-mentioned objects, features, and advantages of this utility model more apparent and understandable, the specific embodiments of this utility model will be described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a full understanding of this utility model. However, this utility model can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this utility model. Therefore, this utility model is not limited to the specific embodiments disclosed below.

[0017] In the description of this utility model, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.

[0018] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this utility model, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0019] In this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or a connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0020] In this utility model, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0021] It should be noted that when an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. When an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementation.

[0022] Please see Figures 2 to 3 This utility model provides a battery charging and discharging management circuit for managing the charging and discharging of nickel-cadmium or nickel-metal hydride batteries. The battery charging and discharging management circuit includes a microcontroller 110, a microcontroller power supply circuit 10, an input voltage detection circuit 20, an input voltage start / stop circuit 30, a trickle charging circuit 40, a constant current charging circuit 50, a battery charging overcurrent detection circuit 60, a battery charging / discharging overtemperature detection circuit 70, a battery voltage detection circuit 80, a battery discharging switch circuit 90, a circuit operating status indicator circuit 100, and a battery interface 120. The microcontroller power supply circuit 10, the input voltage detection circuit 20, the input voltage start / stop circuit 30, the trickle charging circuit 40, the constant current charging circuit 50, the battery charging overcurrent detection circuit 60, the battery charging / discharging overtemperature detection circuit 70, the battery voltage detection circuit 80, the battery discharging switch circuit 90, and the circuit operating status indicator circuit 100 are all connected to the microcontroller 110.

[0023] The trickle charging circuit 40 and the constant current charging circuit 50 are connected in parallel. The external power input terminal is connected to the battery interface 120 through the parallel trickle charging circuit 40 and the constant current charging circuit 50. The external power supply charges the battery through the trickle charging circuit 40 or the constant current charging circuit 50. The input voltage detection circuit 20 detects the voltage at the external power input terminal and feeds it back to the microcontroller 110. The input terminals of the parallel trickle charging circuit 40 and the constant current charging circuit 50 are the charging access terminals. The input voltage start / stop circuit 30 is connected between the external power input terminal and the charging access terminal. The microcontroller 110 controls the circuit's on / off state through the input voltage start / stop circuit 30.

[0024] An external power supply powers the microcontroller 110 through the microcontroller power supply circuit 10. In this embodiment, the battery charging and discharging over-temperature detection circuit 70 is connected to the circuit between the microcontroller power supply circuit 10 and the microcontroller 110. The battery charging and discharging over-temperature detection circuit 70 is equipped with a thermistor NTC. The resistance of the thermistor NTC changes with the temperature of the battery. The battery charging and discharging over-temperature detection circuit 70 detects the temperature of the external battery and feeds it back to the microcontroller 110.

[0025] The circuit operation status indicator circuit 100 is used to indicate the battery's operating status, such as: when the battery is charging: the green indicator light flashes once every 5 seconds; when the battery is fully charged: the green indicator light stays on and stops flashing; when the battery is discharging: the green indicator light flashes once every 1 second; when the battery is fully discharged and cut off: the green indicator light and the yellow indicator light are off; when the battery is disconnected: the yellow fault indicator light flashes once every 0.5 seconds; when the battery is undervoltage or overvoltage: the yellow fault indicator light flashes once every 1 second.

[0026] The battery charging overcurrent detection circuit 60 is connected to the battery interface 120. The battery charging overcurrent detection circuit 60 is used to detect the current during battery charging and feed it back to the microcontroller 110.

[0027] The battery voltage detection circuit 80 is connected to the battery interface 120. The battery voltage detection circuit 80 is used to detect the battery voltage during charging and discharging and feed it back to the microcontroller 110.

[0028] The battery discharge switch circuit 90 is connected to the battery interface 120. The battery discharge switch circuit 90 is connected to the circuit between the battery and the external load and is used to control the on / off state of the circuit between the battery and the external load.

[0029] This utility model employs two charging circuits: a trickle charging circuit 40 and a constant current charging circuit 50. Trickle charging with a small current is used during the initial charging and near-full charge stages, while constant current charging is used during the intermediate stages.

[0030] When the microcontroller 110 detects that the battery voltage is less than 7.5V, it activates the trickle charging circuit 40 to perform trickle charging. When the microcontroller 110 detects that the battery voltage is greater than or equal to 7.5V, it activates the constant current charging circuit 50 to perform constant current charging. In low-temperature environments where the battery voltage curve is steep, in addition to requiring the battery voltage to be greater than or equal to 8.1V, the charging time must also be greater than 10 hours (the charging time is set according to the battery capacity). In this case, the microcontroller 110 activates the trickle charging circuit 40 and deactivates the constant current charging circuit 50, switching to trickle charging in the near-fully charged stage. After the near-fully charged trickle charging stage reaches the set time of 2 hours, charging stops.

[0031] If no power outage occurs thereafter, the microcontroller 110 will activate the trickle charging circuit every 48 hours for 402 hours to replenish the battery's power loss due to its own or external factors. When the battery is used to power an external load, the microcontroller 110 will activate the battery discharge switch circuit 90 and shut off the discharge when the battery voltage drops below 5.5V.

[0032] Specifically, the trickle charging circuit 40 includes an NMOS transistor Q6 and a PMOS transistor Q3. The gate of the NMOS transistor Q6 is connected to the microcontroller 110 through a resistor R42. The source of the NMOS transistor Q6 is grounded. The drain of the NMOS transistor Q6 is connected to the gate of the PMOS transistor Q3 through a resistor R40. The source of the PMOS transistor Q3 is connected to the output terminal of the input voltage start / stop circuit 30. The drain of the PMOS transistor Q3 is connected to the battery interface 120.

[0033] When the microcontroller 110 detects that the battery voltage is lower than the set value of 7.5V, the pin BatteryChargeEnable-1 of the microcontroller 110 changes from low level to high level and acts on the gate of NMOS transistor Q6, so that NMOS transistor Q6 conducts to ground, pulls down the gate voltage of PMOS transistor Q3, so that PMOS transistor Q3 changes from the cut-off state to the conduction state, and opens the trickle charging circuit.

[0034] When the battery voltage is greater than the set value of 7.5V, the BatteryChargeEnable-1 pin of the microcontroller 110 changes from high level to low level, the trickle charging circuit 40 is cut off, and the microcontroller 110 turns on the constant current charging circuit 50.

[0035] When the microcontroller 110 detects that the battery voltage is higher than the set value of 8.1V and the constant current charging time is longer than the set time, the BatteryChargeEnable-1 pin of the microcontroller 110 changes from low level to high level again, and the trickle charging circuit is turned on again.

[0036] When the microcontroller 110 detects that the second trickle charging time is greater than 2 hours, charging is complete. The microcontroller 110 then turns off trickle charging, and the BatteryChargeEnable-1 pin of the microcontroller 110 changes from high to low.

[0037] The constant current charging circuit 50 includes transistors Q14, Q9, and Q13, current-limiting resistors (R44, R45, R58), resistor R74, and resistor R76. Transistor Q14 is an NPN transistor, while transistors Q13 and Q9 are PNP transistors. The current-limiting resistors (R44, R45, R58) are connected in parallel. One end of the parallel current-limiting resistor is connected to the output terminal of the input voltage start / stop circuit 30, and the other end is connected to the emitter of transistor Q9. The collector of transistor Q9 is connected to the battery interface 120. The base of transistor Q9 is connected to the collector of transistor Q14 through resistor R74. The emitter of transistor Q14 is grounded, and the base of transistor Q14 is connected to the BatteryChargeEnable pin of the microcontroller 110 through resistor R76. The emitter and base of transistor Q13 are connected in parallel to the current-limiting resistors (R44, R45, R58), and the collector of transistor Q13 is connected to the base of transistor Q9.

[0038] When the microcontroller 110 detects that the battery voltage is higher than the set value of 7.5V, the circuit will switch from trickle charging to constant current charging. The microcontroller 110 pin BatteryChargeEnable outputs a high level, which turns on transistor Q14 to ground, thereby turning on PNP transistor Q9 and starting constant current charging.

[0039] When the constant current charging time reaches the set duration and the battery voltage is greater than 8.1V, the BatteryChargeEnable pin of the microcontroller 110 changes from high level to low level, and the constant current charging is turned off.

[0040] When transistor Q9 is turned on to form a circuit, a voltage drop Veb (approximately 0.6V) is generated between the emitter and base of transistor Q13 and applied to the current-limiting resistors R45, R44, and R58. During the charging process, the battery voltage increases while the voltage drop across the current-limiting resistors remains essentially unchanged, thus achieving constant current charging.

[0041] The beneficial effects of this utility model battery charging and discharging management circuit are as follows: By setting up a microcontroller 110, a trickle charging circuit 40, a constant current charging circuit 50, a battery voltage detection circuit 80, and a battery interface 120, the trickle charging circuit 40, the constant current charging circuit 50, and the battery voltage detection circuit 80 are all connected to the microcontroller 110. During charging, the battery voltage detection circuit 80 feeds back the detection result to the microcontroller 110, and the microcontroller 110 controls the trickle charging circuit 40 and the constant current charging circuit 50 to work. During charging, the microcontroller 110 switches between the trickle charging circuit 40 and the constant current charging circuit 50 according to the battery voltage and charging time, ensuring that the battery can be fully charged under different ambient temperatures without overcharging, which is highly practical.

[0042] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0043] The embodiments described above are merely illustrative of several implementations of this utility model, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the utility model patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this utility model, and these all fall within the protection scope of this utility model. Therefore, the protection scope of this utility model patent should be determined by the appended claims.

Claims

1. A battery charge / discharge management circuit, characterized in that, The system includes a microcontroller, a microcontroller power supply circuit, an input voltage detection circuit, an input voltage start / stop circuit, a trickle charging circuit, a constant current charging circuit, a battery charging overcurrent detection circuit, a battery charging / discharging overtemperature detection circuit, a battery voltage detection circuit, a battery discharge switch circuit, a circuit operating status indicator circuit, and a battery interface. The microcontroller power supply circuit, input voltage detection circuit, input voltage start / stop circuit, trickle charging circuit, constant current charging circuit, battery charging overcurrent detection circuit, battery charging / discharging overtemperature detection circuit, battery voltage detection circuit, battery discharge switch circuit, and circuit operating status indicator circuit are all connected to the microcontroller. The trickle charging circuit and the constant current charging circuit are connected in parallel. The external power input is connected to the battery interface through the parallel trickle charging circuit and constant current charging circuit, and the external power supply charges the battery through the trickle charging circuit or the constant current charging circuit.

2. The battery charge / discharge management circuit according to claim 1, characterized in that, The input terminals of the parallel trickle charging circuit and constant current charging circuit are the charging access terminals. The input voltage start / stop circuit is connected between the external power input terminal and the charging access terminal. The microcontroller controls the circuit's on / off state through the input voltage start / stop circuit.

3. The battery charge / discharge management circuit according to claim 1, characterized in that, The battery charging and discharging over-temperature detection circuit is connected to the circuit between the microcontroller power supply circuit and the microcontroller. The battery charging and discharging over-temperature detection circuit is equipped with a thermistor NTC. The battery charging and discharging over-temperature detection circuit detects the temperature of the external battery and feeds it back to the microcontroller.

4. The battery charge / discharge management circuit according to claim 1, characterized in that, The battery charging overcurrent detection circuit is connected to the battery interface. This battery charging overcurrent detection circuit is used to detect the current during battery charging and feed it back to the microcontroller.

5. The battery charge / discharge management circuit according to claim 1, characterized in that, The battery voltage detection circuit is connected to the battery interface. This battery charging overcurrent detection circuit is used to detect the battery voltage during charging and discharging and feed it back to the microcontroller.

6. The battery charge / discharge management circuit according to claim 2, characterized in that, The battery discharge switch circuit is connected to the battery interface and is connected to the circuit between the battery and the external load to control the on / off state of the circuit between the battery and the external load.

7. The battery charge / discharge management circuit according to claim 1, characterized in that, The trickle charging circuit includes an NMOS transistor Q6 and a PMOS transistor Q3. The gate of the NMOS transistor Q6 is connected to the microcontroller through a resistor R42, the source of the NMOS transistor Q6 is grounded, the drain of the NMOS transistor Q6 is connected to the gate of the PMOS transistor Q3 through a resistor R40, the source of the PMOS transistor Q3 is connected to the output terminal of the input voltage start / stop circuit, and the drain of the PMOS transistor Q3 is connected to the battery interface.

8. The battery charge / discharge management circuit according to claim 7, characterized in that, The constant current charging circuit includes transistors Q14, Q9, and Q13, several current-limiting resistors, resistor R74, and resistor R76. Transistor Q14 is an NPN transistor, while transistors Q13 and Q9 are PNP transistors. The current-limiting resistors are connected in parallel. One end of the parallel current-limiting resistor is connected to the output of the input voltage start / stop circuit, and the other end is connected to the emitter of transistor Q9. The collector of transistor Q9 is connected to the battery interface, and the base of transistor Q9 is connected to the collector of transistor Q14 through resistor R74. The emitter of transistor Q14 is grounded, and the base of transistor Q14 is connected to the microcontroller through resistor R76. The emitter and base of transistor Q13 are connected in parallel to the current-limiting resistor, and the collector of transistor Q13 is connected to the base of transistor Q9.

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