Rechargeable battery charging control device

Abstract

The present invention discloses a rechargeable battery charging control device, comprising an adjustable DC voltage source, a comparison output circuit, a first drive circuit and a connection control device; the connection control device comprises an input interface, an output interface and a controller, the input interface is used to be electrically connected to the output end of the selected charger, the output interface is used to be electrically connected to the rechargeable battery, and the controller is used to control the on / off between the input interface and the output interface; the two comparison input ends of the comparison output circuit are electrically connected to the adjustable DC voltage source and the input interface respectively, and the comparison output circuit can output different control signals according to the voltage difference between its two comparison input ends; the above-mentioned charging control device can be used to control the cut-off voltage of the charger by adjusting the reference voltage output by the adjustable DC voltage source, so that the cut-off voltage output by the charger matches the current rechargeable battery. Thereby, the number of configurations of the charging and discharging cabinets can be reduced, and the production equipment cost can be saved.

Description

Technical Field

[0001] The present invention relates to the technical field of charging control, and in particular to a rechargeable battery charging control device in the process of using a conventional charger to charge the rechargeable battery. Background Art

[0002] For rechargeable batteries, such as lithium-ion batteries, after coming off the production line, they are generally placed in a dedicated charging and discharging cabinet, and the battery is regularly recharged through the charging and discharging cabinet to prevent the battery from running out of power. With the increase in demand for batteries, especially in the peak season, battery production workshops generally have insufficient charging and discharging cabinets. If the configuration of charging and discharging cabinets is increased, firstly, the equipment cost will increase (charging and discharging cabinets are expensive), and secondly, the charging and discharging cabinets may be idle in the off-season, resulting in a waste of resources. Therefore, it is possible to consider using a commonly used battery charger on the market to recharge the battery. However, since the battery chargers on the market are not standard configurations for the batteries produced, that is, the full-charge voltage recognized by the charger is different from the full-charge voltage required by the battery, this requires real-time monitoring of the charging voltage of the charger. When the charging voltage reaches the target level, the charging state should be automatically disconnected to achieve the ideal recharging purpose. Summary of the invention

[0003] The object of the present invention is to solve the above technical problems and to provide a rechargeable battery charging control device which can control the cut-off voltage of the charger according to the full-charge voltage required by the rechargeable battery.

[0004] In order to achieve the above-mentioned object, the present invention discloses a rechargeable battery charging control device, including an adjustable DC voltage source, a comparison output circuit, a first drive circuit and a connection control device;

[0005] The connection control device comprises an input interface, an output interface and a controller, wherein the input interface is used to be electrically connected to the output end of the selected charger, the output interface is used to be electrically connected to the rechargeable battery, and the controller is used to control the connection / disconnection between the input interface and the output interface;

[0006] The two comparison input terminals of the comparison output circuit are electrically connected to the adjustable DC voltage source and the input interface respectively, and the comparison output circuit can output different control signals according to the voltage difference between the two comparison input terminals;

[0007] The first driving circuit is electrically connected to the output terminal of the comparison output circuit, and is used to drive the controller to operate according to different control signals.

[0008] Preferably, the comparison output circuit comprises a differential amplifier.

[0009] Preferably, a capacitor is electrically connected between the output terminal and the inverting input terminal of the differential amplifier.

[0010] Preferably, the non-inverting input terminal of the differential amplifier is electrically connected to the adjustable DC voltage source, and the inverting input terminal of the differential amplifier is electrically connected to the input interface.

[0011] Preferably, the first driving circuit includes a first three-pole driver, a first driving power supply and a first current limiting resistor; the control end of the first three-pole driver is electrically connected to the output end of the differential amplifier through the first current limiting resistor, the first driving power supply is electrically connected to the power input end of the first three-pole driver, and the power output end of the first three-pole driver is electrically connected to the controller.

[0012] Preferably, the first driving circuit also includes a starting switch, the two ends of the starting switch are respectively electrically connected between the power input terminal and the power output terminal of the first three-pole driver, and the starting switch is used to short-circuit the power path between the first driving power supply and the controller.

[0013] Preferably, the controller is an electromagnetic relay.

[0014] Preferably, it also includes a second drive circuit electrically connected to the output end of the comparison output circuit and connected in parallel with the first drive circuit, and an indicator electrically connected to the second drive circuit, wherein the second drive circuit is used to drive the indication state change of the indicator according to different control signals.

[0015] Preferably, the second driving circuit includes a second three-pole driver, a second driving power supply and a second current limiting resistor; the control end of the second three-pole driver is electrically connected to the output end of the differential amplifier through the second current limiting resistor, the second driving power supply is electrically connected to the power input end of the second three-pole driver, and the power output end of the second three-pole driver is electrically connected to the indicator.

[0016] Preferably, a diode is further provided between the control ends of the first three-pole driver and the second three-pole driver, and the positive terminal of the diode is electrically connected to the controller of the first three-pole driver.

[0017] Compared with the prior art, the main beneficial effects of the rechargeable battery charging control device of the present invention include:

[0018] 1. The output voltage of the adjustable DC voltage source can be adjusted according to the full charge voltage required by the rechargeable battery, so as to set the cut-off voltage of the charger, so that when the charger fully charges the rechargeable battery, the connection between the charger and the rechargeable battery is automatically disconnected, which can effectively reduce the number of configurations of the charging and discharging cabinets and save the cost of production equipment;

[0019] 2. Since a second driving circuit and an indicator are also provided at the output end of the comparison output circuit, when the battery is fully charged, the state of the indicator changes. Therefore, the charging state can be monitored by the indicator, which is convenient to use;

[0020] 3. Since a capacitor is electrically connected between the output terminal and the non-inverting input terminal of the differential amplifier, the charger can be disconnected from the rechargeable battery after the charging voltage exceeds the set voltage for a period of time, thereby ensuring that the charging is in place and avoiding false fullness. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 Schematic diagram of the principle structure of a rechargeable battery charging control device in an embodiment of the present invention.

[0022] Figure 2 4 is a circuit diagram of a rechargeable battery charging control device in an embodiment of the present invention. DETAILED DESCRIPTION

[0023] In order to explain the technical content, structural features, achieved objectives and effects of the present invention in detail, the following is a detailed description in conjunction with the implementation methods and the accompanying drawings.

[0024] The present embodiment discloses a rechargeable battery charging control device, which is used to control the cut-off voltage of the rechargeable battery using a conventional charger, so that when the voltage of the rechargeable battery is charged to a target value, the charger can automatically disconnect from the rechargeable battery. The rechargeable battery in this embodiment and the following embodiments is a lithium battery pack as an example, but it is not limited to this. The conventional charger is a lithium ion charger well known to those skilled in the art. The maximum charging voltage that the charger can provide does not have to match the lithium battery pack. The maximum charging voltage of the charger is required to be greater than or equal to the full charging voltage of the lithium battery pack, and the charger is required to be a constant current type, that is, the charger charges the lithium battery pack with a constant charging current, and the charging voltage during the charging process is from small to large.

[0025] like Figure 1 As shown, the power replenishment control device includes an adjustable DC voltage source 1, a comparison output circuit 2, a first drive circuit 3 and a connection control device 4. The adjustable DC voltage source 1 in this embodiment is used to output an adjustable DC voltage. The DC voltage output by the adjustable DC voltage source 1 is the cut-off voltage required to be reached by the charger 8, that is, the adjustable DC voltage source 1 is a reference voltage source.

[0026] The connection control device 4 includes an input interface 40, an output interface 41 and a controller 42. The input interface 40 is used to electrically connect to the output end of the selected charger 8, the output interface 41 is used to electrically connect to the lithium battery pack 7, and the controller 42 is used to control the on / off between the input interface 40 and the output interface 41. When the lithium battery pack 7 is charged, the output end of the selected charger 8 is connected to the input interface 40, and the charging input end of the lithium battery pack 7 is connected to the output interface 41. The charger 8 and the lithium battery pack 7 are electrically connected through the input interface 40 and the output interface 41.

[0027] The two comparison input terminals of the comparison output circuit 2 are electrically connected to the adjustable DC voltage source 1 and the input interface 40 respectively, and the comparison output circuit 2 can output different control signals according to the voltage difference between its two comparison input terminals. The first drive circuit 3 is electrically connected to the output terminal of the comparison output circuit 2, and is used to drive the action of the controller 42 according to different control signals, so that the controller 42 controls the on / off of the input interface 40 and the output interface 41 according to the control signal.

[0028] The working principle of the power replenishment control device disclosed in the above embodiment is:

[0029] First, the adjustable DC voltage source 1 provides a reference voltage source for the comparison output circuit 2. The adjustable DC voltage source 1 is adjusted to output a suitable reference voltage according to the full charge voltage required by the lithium battery pack 7, so that the reference voltage can be equal to the full charge voltage or slightly greater than the full charge voltage. Secondly, the comparison output circuit 2 outputs different control signals according to the difference between the charging voltage output by the charger 8 and the reference voltage. For example, in the initial charging stage, the charging voltage output by the charger 8 is relatively small and is less than the reference voltage. The comparison output circuit 2 outputs a first control signal. The first control signal enables the controller 42 to control the input interface 40 and the output interface 41 to remain in a connected state. When fully charged, the charging voltage output by the charger 8 is slightly greater than (or equal to) the reference voltage. Then, the control signal output by the comparison output circuit 2 changes to a second control signal. The second control signal enables the controller 42 to control the input interface 40 and the output interface 41 to be disconnected, so that the lithium battery pack 7 can be automatically disconnected from the charger 8 after being fully charged. It can be seen that, through the above-mentioned power replenishment control device, the cut-off voltage of the charger 8 can be controlled by adjusting the reference voltage output by the adjustable DC voltage source 1, so that the cut-off voltage output by the charger 8 matches the current lithium battery pack 7. Therefore, through the use of the above-mentioned power replenishment control device, the number of configurations of the charging and discharging cabinets can be reduced, thereby saving the production equipment cost.

[0030] Please refer to Figure 1 and Figure 2, the comparison output circuit 2 includes a differential amplifier A1, which outputs a high level or a low level according to the difference between the charging voltage output by the charger 8 and the reference voltage output by the adjustable DC voltage source 1. Specifically, the non-inverting input terminal of the differential amplifier A1 is electrically connected to the adjustable DC voltage source 1 to obtain the reference voltage signal VCC0, and the reverse input terminal of the differential amplifier A1 is electrically connected to the input interface 40 to obtain the charging voltage signal Vin. When the charging voltage output by the charger 8 is less than the reference voltage output by the adjustable DC voltage source 1, the differential amplifier A1 outputs a high level, and the first drive circuit 3 causes the controller 42 to perform a corresponding action according to the high level, thereby connecting the input interface 40 with the output interface 41. When the charging voltage output by the charger 8 is greater than or equal to the reference voltage output by the adjustable DC voltage source 1, the differential amplifier A1 outputs a low level, and the first drive circuit 3 causes the controller 42 to perform a corresponding action according to the low level, thereby disconnecting the input interface 40 from the output interface 41. Preferably, the controller 42 is preferably an electromagnetic relay K1.

[0031] More specifically, if Figure 2 As shown, the adjustable DC voltage source 1 is connected to the same-direction input terminal of the differential amplifier A1 through the first voltage-dividing resistor R3 and the second voltage-dividing resistor R6 connected in series, and the same-direction input terminal of the differential amplifier A1 is connected between the first voltage-dividing resistor R3 and the second voltage-dividing resistor R3. The input interface 40 is connected to the reverse input terminal of the differential amplifier A1 through the third voltage-dividing resistor R7 and the fourth voltage-dividing resistor R10, and the reverse input terminal of the differential amplifier A1 is connected between the third voltage-dividing resistor R7 and the fourth voltage-dividing resistor R10. Moreover, the ratio of the first voltage-dividing resistor R3 to the second voltage-dividing resistor R6 is equal to the ratio of the third voltage-dividing resistor R7 to the fourth voltage-dividing resistor R10, so that when the charging voltage signal Vin output by the charger 8 is equal to the reference voltage signal VCC0, the values ​​input to the two input terminals of the differential amplifier A1 are equal.

[0032] To improve the anti-interference performance of the two input terminals of the differential amplifier A1, preferably, please refer to Figure 2 A common mode capacitor C2 and a common mode resistor R8 are also connected in series between the same direction input terminal of the differential amplifier A1 and the input interface 40. The common mode capacitor C2 and the common mode resistor R8 together form a common mode of a small interference signal, and the common mode is input into the same direction input terminal of the differential amplifier A1 to offset the interference signal from the input interface 40 received at the reverse input terminal, thereby improving the anti-interference performance. In addition, a common direction input resistor R5 and a reverse input resistor R9 are also respectively provided at the same direction input terminal and the reverse input terminal of the differential amplifier A1. The same direction input resistor R5 can buffer the change of the same direction input terminal caused by the voltage change of the common mode capacitor C2, and the reverse input resistor R9 can buffer the change of the reverse input terminal caused by the voltage change from the input interface 40.

[0033] like Figure 2 In order to facilitate the setting of the reference voltage and ensure that the lithium battery pack 7 is fully charged when the charger 8 reaches the cut-off voltage, a capacitor C1 can be electrically connected between the output terminal and the reverse input terminal of the differential amplifier A1. During the charging process, the voltage at the same-direction input terminal of the differential amplifier A1 is greater than the voltage at the reverse input terminal. The capacitor C1 is connected to the output terminal of the differential amplifier A1 at one end as the positive electrode and the other end as the negative electrode, and continuously stores electricity. When the voltage at the same-direction input terminal of the differential amplifier A1 is equal to the voltage at the reverse input terminal, the capacitor C1 starts to discharge, so that the output terminal of the differential amplifier A1 continues to maintain a high level for a certain period of time, thereby ensuring that the lithium battery pack 7 is fully charged. After the capacitor C1 is discharged, since the charging voltage at the output terminal of the charger 8 is greater than the reference voltage at this time, the differential amplifier A1 outputs a low level, so that the input interface 40 is disconnected from the output interface 41.

[0034] Further improvements such as Figure 2 , the first driving circuit 3 includes a first three-pole driver Q1, a first driving power supply and a first current limiting resistor R4, and the first driving power supply provides a first power supply signal VCC2. The control terminal G1 of the first three-pole driver Q1 is electrically connected to the output terminal of the differential amplifier A1 through the first current limiting resistor R4, the first driving power supply is electrically connected to the power input terminal of the first three-pole driver Q1, and the power output terminal of the first three-pole driver Q1 is electrically connected to the controller 42 (that is, the electromagnetic relay K1). In this embodiment, the first three-pole driver Q1 is a switch-type NPN transistor Q1. When the differential amplifier A1 outputs a high level, a base current exists in the NPN transistor Q1 and is turned on, connecting the power path between the first driving power supply and the electromagnetic relay K1, and the electromagnetic relay K1 is energized, connecting the input interface 40 and the output interface 41. When the differential amplifier A1 outputs a low level, the NPN transistor Q1 is turned off, disconnecting the power path between the first driving power supply and the electromagnetic relay K1, and the electromagnetic relay K1 loses power, thereby disconnecting the connection between the input interface 40 and the output interface 41.

[0035] Preferably, the first drive circuit 3 further includes a start switch S1, the two ends of which are electrically connected between the power input end and the power output end of the first three-pole driver Q1, respectively, and the start switch S1 is used to short-circuit the power path between the first drive power supply and the controller 42 (ie, the electromagnetic relay K1). When charging starts, the input interface 40 and the output interface 41 are connected by pressing the start switch S1.

[0036] Furthermore, if Figure 1As shown, the power replenishment control device in this embodiment further includes a second drive circuit 5 electrically connected to the output end of the comparison output circuit 2 and connected in parallel with the first drive circuit 3, and an indicator 6 electrically connected to the second drive circuit 5, and the second drive circuit 5 is used to drive the indicator 6 to change its indication state according to different control signals. Specifically, as Figure 2 , the second driving circuit 5 includes a second triode driver Q2, a second driving power supply and a second current limiting resistor, and the second driving power supply provides a second power supply signal VCC3. The control terminal G2 of the second triode driver Q2 is electrically connected to the output terminal of the differential amplifier A1 through the second current limiting resistor R2, the second driving power supply is electrically connected to the power input terminal of the second triode driver Q2, and the power output terminal of the second triode driver Q2 is electrically connected to the indicator 6. In this embodiment, the second triode driver Q2 is preferably a switching type PNP transistor Q2, and the indicator 6 is preferably a light emitting diode LED. During the charging process, the differential amplifier A1 outputs a high level, the PNP transistor Q2 is cut off, and the light emitting diode LED is in an off state. When the charging is completed, the differential amplifier A1 outputs a low level, and the PNP transistor Q2 has a base current and is turned on, thereby lighting up the light emitting diode LED to prompt the staff that the power replenishment work is completed.

[0037] Further improvement, since the first three-pole driver Q1 uses an NPN transistor Q1, when the output end of the differential amplifier A1 changes from a high level to a low level, there is a junction capacitance (parasitic capacitance) at the position where the NPN transistor Q1 is connected to the first current limiting resistor R4. If it is not processed, the junction capacitance will enter the NPN transistor Q1, delaying the time when the NPN transistor Q1 is cut off. Therefore, a diode D1 can be set between the control end of the first three-pole driver Q1 and the second three-pole driver Q2, and the positive terminal of the diode D1 is electrically connected to the controller 42 of the first three-pole driver Q1. In this embodiment, when the output end of the differential amplifier A1 changes from a high level to a low level, the junction capacitance generated at the position where the NPN transistor Q1 is connected to the first current limiting resistor R4 is released through the diode D1, thereby ensuring that the electromagnetic relay K1 disconnects the connection between the input interface 40 and the output interface 41 before the light-emitting diode LED is lit. In addition, a freewheeling diode D2 is provided at both ends of the electromagnetic relay K1 for freewheeling when the input of the electromagnetic relay K1 is disconnected, thereby eliminating the negative impact of the induced current generated by the inductor.

[0038] In summary, if Figure 1 and Figure 2As shown, the above embodiment discloses a charging control device for a rechargeable battery 7. When in use, first, the reference voltage output by the adjustable DC voltage source 1 is adjusted according to the full charging voltage required by the lithium battery pack 7. For example, if the charger 8 is 24V and the full charging voltage required by the lithium battery pack is 22V, then the reference voltage output by the adjustable DC voltage source 1 is adjusted to 22V. At this time, since the input interface 40 and the output interface 41 are disconnected, the voltage output by the charger 8 is a no-load voltage, which is higher than 22V (also higher than 24V), and the differential amplifier A1 outputs a low level. Therefore, the electromagnetic relay K1 In the power-off state, the light-emitting diode LED is always in the light state; then, the start switch S1 is pressed. After the start switch S1 is pressed, the electromagnetic relay K1 is energized, and the input interface 40 and the output interface 41 are connected, so that the output end of the charger 8 is connected to the lithium battery pack 7, and charging begins. At this time, the charging voltage output by the charger 8 is less than the reference voltage, the differential amplifier A1 outputs a high level, the NPN transistor Q1 is turned on, and the PNP transistor Q2 is turned off. Therefore, when the light-emitting diode LED is seen to be off, the start switch S1 is released, and the NPN transistor Q1 still remains in the on state. When the voltage of the input interface 40 is equal to the reference voltage, the signals at the two input terminals of the differential amplifier A1 (VCC0=Vin) are equal. At this time, under the action of the capacitor C1, the output terminal of the differential amplifier A1 continues to maintain a high level state. After the capacitor C1 is discharged, the charging voltage of the input interface 40 is greater than the reference voltage, the output terminal of the differential amplifier A1 becomes a low level, the input interface 40 is disconnected from the output interface 41, and the light-emitting diode LED is lit again. Therefore, when the light-emitting diode LED is lit, it means that the power replenishment is completed.

[0039] The above disclosure is only the preferred embodiment of the present invention, which certainly cannot be used to limit the scope of rights of the present invention. Therefore, equivalent changes made according to the scope of the patent application of the present invention are still within the scope covered by the present invention.

Claims

1. A rechargeable battery charging control device, characterized in that: It includes an adjustable DC voltage source, a comparison output circuit, a first drive circuit and a connection control device; The connection control device comprises an input interface, an output interface and a controller, wherein the input interface is used to be electrically connected to the output end of the selected charger, the output interface is used to be electrically connected to the rechargeable battery, and the controller is used to control the connection / disconnection between the input interface and the output interface; The two comparison input terminals of the comparison output circuit are electrically connected to the adjustable DC voltage source and the input interface respectively, and the comparison output circuit can output different control signals according to the voltage difference between the two comparison input terminals; The first driving circuit is electrically connected to the output end of the comparison output circuit, and is used to drive the action of the controller according to different control signals; the comparison output circuit includes a differential amplifier; the non-inverting input end of the differential amplifier is electrically connected to the adjustable DC voltage source, and the reverse input end of the differential amplifier is electrically connected to the input interface; the first driving circuit includes a first three-pole driver, a first driving power supply and a first current limiting resistor; the control end of the first three-pole driver is electrically connected to the output end of the differential amplifier through the first current limiting resistor, the first driving power supply is electrically connected to the power input end of the first three-pole driver, and the power output end of the first three-pole driver is electrically connected to the controller; The first driving circuit also includes a starting switch, the two ends of which are electrically connected between the power input terminal and the power output terminal of the first three-pole driver, respectively. The starting switch is used to short-circuit the power path between the first driving power supply and the controller in the charging startup phase and in a pressed state.

2. The rechargeable battery charging control device according to claim 1, characterized in that: A capacitor is electrically connected between the output terminal and the reverse input terminal of the differential amplifier.

3. The rechargeable battery charging control device according to claim 1, characterized in that: The controller is an electromagnetic relay.

4. The rechargeable battery charging control device according to claim 1, characterized in that: It also includes a second drive circuit electrically connected to the output end of the comparison output circuit and connected in parallel with the first drive circuit, and an indicator electrically connected to the second drive circuit, wherein the second drive circuit is used to drive the indicator to change its indication state according to different control signals.

5. The rechargeable battery charging control device according to claim 4, characterized in that: The second driving circuit includes a second three-pole driver, a second driving power supply and a second current limiting resistor; the control end of the second three-pole driver is electrically connected to the output end of the differential amplifier through the second current limiting resistor, the second driving power supply is electrically connected to the power input end of the second three-pole driver, and the power output end of the second three-pole driver is electrically connected to the indicator.

6. The rechargeable battery charging control device according to claim 5, characterized in that: A diode is further provided between the control ends of the first three-pole driver and the second three-pole driver, and the positive terminal of the diode is electrically connected to the controller of the first three-pole driver.

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