CN210839042U

CN210839042U - 1800W sealed lithium battery charging module

Info

Publication number: CN210839042U
Application number: CN201922054663.2U
Authority: CN
Inventors: 周磊; 廖谦; 于海峰; 陈华贵; 徐云; 李笑兰
Original assignee: Hubei Jiachenda New Energy Technology Co ltd
Current assignee: Hubei Jiachenda New Energy Technology Co ltd
Priority date: 2019-11-25
Filing date: 2019-11-25
Publication date: 2020-06-23
Anticipated expiration: 2029-11-25

Abstract

The utility model provides a 1800W sealed lithium battery charging module, including LLC resonance converting circuit, constant current constant voltage charging circuit includes comparator U1, comparator U2, TL431 chip U3, resistance R1, resistance R2, resistance R3, resistance R9, the utility model discloses the circuit need not on-off control elements such as a large amount of triodes, and circuit structure is simple, is favorable to reduce cost.

Description

1800W sealed lithium battery charging module

Technical Field

The utility model relates to a lithium battery charging technology field especially relates to a 1800W sealed lithium battery charging module.

Background

In recent years, the demand of lithium batteries in the fields of household appliances, portable electronic equipment, electric automobiles, electric tools and the like is continuously increased, and 1800W sealed lithium batteries are common lithium batteries in the market and are suitable for medium-sized lithium battery powered vehicles or equipment. The charging mode of the lithium battery generally comprises constant current charging, constant voltage charging and constant current and constant voltage charging, wherein in the constant current charging process, the voltage of the battery is gradually increased, and when the voltage reaches a certain value, the battery is considered to be fully charged, but the battery is difficult to be fully charged by constant current voltage-limiting charging; in the process of constant voltage charging, the charging current is gradually reduced, the lowest charging current is set, and when the current is lower than the threshold value, the battery is considered to be fully charged, but the charging current in the early stage of constant voltage charging is very large, so that the internal structure of the battery can be damaged, and the service life of the battery can be influenced.

The lithium battery in the prior art is mostly in a constant-current constant-voltage charging mode, generally has two-stage charging and three-stage charging, and generally adopts two-stage charging, namely constant current and constant voltage, but because the traditional constant-current constant-voltage charging circuit uses switching tubes such as triodes and the like as feedback control elements in a large quantity, the circuit structure is complex, and the cost is not reduced.

SUMMERY OF THE UTILITY MODEL

In view of this, the utility model provides a 1800W sealed lithium battery charging module to solve traditional constant current constant voltage charging circuit and use the switch tube such as triode in a large number as feedback control element, make circuit structure complicated, be unfavorable for reduce cost's problem.

The technical scheme of the utility model is realized like this: the utility model provides a 1800W sealed lithium battery charging module, including LLC resonance converting circuit, constant current constant voltage charging circuit includes comparator U1, comparator U2, TL431 chip U3, resistance R1, resistance R2, resistance R3, resistance R9; the positive electrode of the output end of the LLC resonant conversion circuit is grounded through a resistor R1 and a resistor R2 in sequence, the common end of the resistor R1 and the resistor R2 is connected with the inverting input end of a comparator U1, the positive electrode of the output end of the LLC resonant conversion circuit is grounded through a resistor R3, the cathode of a TL431 chip U3 and the anode of a TL431 chip U3 in sequence, the common ends of the resistor R3 and the TL431 chip U3 are connected with the non-inverting input end of the comparator U1, and the output end of the comparator U1 is connected with the feedback control end of a controller U6 of the LLC resonant conversion circuit; the reference pole of the TL431 chip U3 is connected with the non-inverting input end of the comparator U2, the negative pole of the output end of the LLC resonant conversion circuit is connected with the inverting input end of the comparator U2 through a resistor R9, and the output end of the comparator U2 is also connected with the feedback control end.

Optionally, the constant-current constant-voltage charging circuit further includes a diode D1 and a diode D2; the diode D1 is connected between the output end of the comparator U1 and the feedback control end, the anode of the diode D1 is connected with the output end of the comparator U1, and the cathode of the diode D1 is connected with the feedback control end; the diode D2 is connected between the output end of the comparator U2 and the feedback control end, the anode of the diode D2 is connected with the output end of the comparator U2, and the cathode of the diode D2 is connected with the feedback control end.

Optionally, the constant-current constant-voltage charging circuit further includes a voltage follower U4, and the voltage follower U4 is connected between the output terminal of the comparator U1 and the feedback control terminal.

Optionally, the constant-current constant-voltage charging circuit further includes a photoelectric coupler U5, a positive electrode of an input end of the photoelectric coupler U5 is connected to a positive electrode of an output end of the LLC resonant conversion circuit, a negative electrode of an input end of the photoelectric coupler U5 is connected to an output end of the comparator U1 and an output end of the comparator U2, a positive electrode of an output end of the photoelectric coupler U5 is connected to the feedback control end, and a negative electrode of an output end of the photoelectric coupler U5 is grounded.

Optionally, the photocoupler U5 is a PC817 chip.

Optionally, the constant-current constant-voltage charging circuit further includes a resistor R13, a resistor R14, and a resistor R15, an anode of an output terminal of the photoelectric coupler U5 is connected to a feedback receiving pin of the feedback control terminal through a resistor R13 and a resistor R14 in sequence, and a common terminal of the resistor R13 and the resistor R14 is connected to a capacitor discharging pin of the feedback control terminal through a resistor R15.

Optionally, the constant-current constant-voltage charging circuit further includes a resistor R5, a resistor R11, a capacitor C1, and a capacitor C2, an output end of the comparator U1 is sequentially connected to an inverting input end of the comparator U1 through a resistor R5 and a capacitor C1, and an output end of the comparator U2 is sequentially connected to an inverting input end of the comparator U2 through a resistor R11 and a capacitor C2.

Optionally, the controller U6 is an L6599 chip.

The utility model discloses a 1800W sealed lithium battery charging module has following beneficial effect for prior art:

(1) the 1800W sealed lithium battery charging module of the utility model does not need a large number of switching control elements such as triodes, has simple circuit structure and is beneficial to reducing the cost;

(2) the resistor R5 and the capacitor C1 form a phase compensation circuit for performing phase compensation on the constant-voltage feedback loop, the resistor R11 and the capacitor C2 form a phase compensation circuit for performing phase compensation on the constant-current feedback loop, and the phase compensation branch can reduce loop gain when the switching frequency of the circuit is high, ensure that the phase shift is kept unchanged when the switching frequency is very high, avoid negative feedback circuit oscillation and further improve the accuracy of constant-current and constant-voltage control.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.

Fig. 1 is a block diagram of a 1800W sealed lithium battery charging module according to the present invention;

fig. 2 is a circuit diagram of the constant current and constant voltage charging circuit of the present invention;

fig. 3 is another circuit diagram of the constant current and constant voltage charging circuit of the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be described clearly and completely below with reference to the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work all belong to the protection scope of the present invention.

As shown in fig. 1, with reference to fig. 2, the 1800W sealed lithium battery charging module of the present invention includes an LLC resonant converting circuit, a constant-current constant-voltage charging circuit, which includes a comparator U1, a comparator U2, a TL431 chip U3, a resistor R1, a resistor R2, a resistor R3, and a resistor R9; the positive electrode of the output end of the LLC resonant conversion circuit is grounded through a resistor R1 and a resistor R2 in sequence, the common end of the resistor R1 and the resistor R2 is connected with the inverting input end of a comparator U1, the positive electrode of the output end of the LLC resonant conversion circuit is grounded through a resistor R3, the cathode of a TL431 chip U3 and the anode of a TL431 chip U3 in sequence, the common ends of the resistor R3 and the TL431 chip U3 are connected with the non-inverting input end of the comparator U1, and the output end of the comparator U1 is connected with the feedback control end of a controller U6 of the LLC resonant conversion circuit; the reference pole of the TL431 chip U3 is connected with the non-inverting input end of the comparator U2, the negative pole of the output end of the LLC resonant conversion circuit is connected with the inverting input end of the comparator U2 through a resistor R9, and the output end of the comparator U2 is also connected with the feedback control end.

The controller U6 is used for frequency conversion control of a resonant half bridge in an LLC resonant conversion circuit, can output two complementary drive signals with duty ratios of 50% for controlling two power switch tubes of the resonant half bridge, drives the on and off phases of the high-side switch and the low-side switch at 180 degrees, and the function and control process of the controller U6 are parts of a traditional 1800W sealed lithium battery charging module, which are common and are not repeated herein. The feedback control end of the controller U6 comprises a feedback receiving pin and a capacitor discharging pin, the feedback receiving pin is used for receiving a charging current or voltage signal fed back by the constant-current constant-voltage charging circuit, and the capacitor discharging pin is used for changing the discharging frequency of the capacitor according to the feedback signal received by the feedback receiving pin so as to change the switching frequency of a resonant half bridge in the LLC resonant conversion circuit and correct the charging signal. The controller U6 may be an L6599 chip, and the feedback receiving pin and the capacitor discharging pin are No. 4 and No. 3 pins of the L6599 chip, respectively.

Generally, as shown in fig. 1, the 1800W sealed lithium battery charging module further includes an EMI filter circuit, a rectifier bridge, and a PFC circuit, wherein 220V ac power is connected to an input terminal of the EMI filter circuit, and an output terminal of the EMI filter circuit is connected to the 1800W sealed lithium battery through the rectifier bridge, the PFC circuit, and the LLC resonant conversion circuit in sequence, wherein 220V input of the utility power passes through the EMI filter circuit, thereby preventing common mode and differential mode signals from interfering with the power grid; after EMI filtering, rectifying the EMI filtered EMI into pulsating voltage through a rectifier bridge, and performing power factor correction through a PFC circuit so as to improve a power factor and inhibit harmonic current; the direct-current high voltage output by the PFC circuit is input into the LLC resonant conversion circuit conversion topology, and a constant current or a constant voltage is output to charge the 1800W sealed lithium battery pack under the feedback of the constant-current constant-voltage charging circuit.

In this embodiment, the TL431 chip U3 is a controllable precision regulator that provides a precise 2.5V reference voltage to the non-inverting input of the comparator U1 and the comparator U2. In the constant-current charging stage, output current of the LLC resonance conversion circuit is sampled by a resistor R9 and then converted into a voltage signal and input into an inverting input end of a comparator U2, forward input voltage of the comparator U2 is obtained by dividing 2.5V reference voltage by voltage dividing resistors R7 and R8, homodromous voltage and reverse voltage of the comparator U2 are compared to output an error amplification signal, the error amplification signal is fed back to a No. 4 pin of an L6599 chip, the discharging frequency of a No. 3 pin capacitor is changed, the change of the switching frequency is realized, and the charging module is ensured to keep constant-current charging in the constant-current stage. In the constant voltage charging stage, the output voltage of the LLC resonant conversion circuit is divided by voltage dividing resistors R1 and R2 and then input into the inverting input end of a comparator U1, if the output voltage of the LLC resonant conversion circuit rises, the input voltage of the inverting input end of the comparator U1 also rises, an error amplification signal is output after comparison with a 2.5V reference voltage, the error amplification signal is fed back to a No. 4 pin of an L6599 chip, the discharging frequency of a No. 3 pin capacitor is changed, the change of the switching frequency is realized, and the charging module is ensured to keep constant voltage charging in the constant voltage stage. The resistor R9 is a current sampling resistor, and the resistor R3 is a voltage dividing resistor.

Therefore, the 1800W sealed lithium battery charging module of the embodiment can carry out constant-current constant-voltage charging on the 1800W sealed lithium battery, and the circuit does not need a large number of switching control elements such as triodes and the like, has a simple circuit structure and is beneficial to reducing the cost.

Optionally, as shown in fig. 2, the constant-current constant-voltage charging circuit further includes a diode D1 and a diode D2; the diode D1 is connected between the output end of the comparator U1 and the feedback control end, the anode of the diode D1 is connected with the output end of the comparator U1, and the cathode of the diode D1 is connected with the feedback control end; the diode D2 is connected between the output end of the comparator U2 and the feedback control end, the anode of the diode D2 is connected with the output end of the comparator U2, and the cathode of the diode D2 is connected with the feedback control end.

The diode D1 and the diode D2 are respectively used for isolating the comparator U1 from the controller U6 and isolating the comparator U2 from the controller U6, so that current is prevented from flowing to the two comparators from the controller U6, and the safety of the circuit is improved.

Optionally, as shown in fig. 3, the constant-current constant-voltage charging circuit further includes a voltage follower U4, and the voltage follower U4 is connected between the output terminal of the comparator U1 and the feedback control terminal.

The non-inverting input end of the voltage follower U4 is connected with the output end of the comparator U1, the inverting input end of the voltage follower U4 is connected with the feedback control end through the diode D1, and the inverting input end of the voltage follower U4 is also directly connected with the output end of the voltage follower U4. The comparator U1 is used to amplify the voltage, the output impedance is high, if the input impedance of the next stage is small, a considerable part of the signal will be lost in the output resistor of the previous stage, and the voltage follower U4 is used to match the impedance, so as to improve the ability of driving the next stage circuit.

Optionally, as shown in fig. 3, the constant-current constant-voltage charging circuit further includes a photocoupler U5, an anode of an input end of the photocoupler U5 is connected to an anode of an output end of the LLC resonant conversion circuit, a cathode of an input end of the photocoupler U5 is connected to an output end of the comparator U1 and an output end of the comparator U2, an anode of an output end of the photocoupler U5 is connected to the feedback control end, and a cathode of an output end of the photocoupler U5 is grounded.

Optionally, the photocoupler U5 is a PC817 chip. The positive electrode of the input end, the negative electrode of the input end, the positive electrode of the output end and the negative electrode of the output end of the photoelectric coupler U5 are the positive electrode of a light emitting diode of a U5 of the photoelectric coupler, the negative electrode of a light emitting diode of a U5 of the photoelectric coupler, the collector electrode of a phototriode of a U5 of the photoelectric coupler and the emitter electrode of a phototriode of a U5 of the photoelectric coupler in sequence. In this embodiment, if the charging current or the charging voltage is too large, the potential of the negative electrode of the light emitting diode of the photocoupler U5 is pulled low, the light emitting diode is turned on to emit light, and the conduction of the phototriode is controlled, so that the current potential held by the feedback control end of the controller U6 is increased. If the charging current or the charging voltage is too small, the potential of the cathode of the light emitting diode of the photoelectric coupler U5 is kept at a high level, the light emitting diode is not conducted, the phototriode is turned off, and the current potential kept by the feedback control end of the controller U6 is reduced. The photoelectric coupler U5 is used for isolating an electric signal between the controller U6 and the constant-current constant-voltage charging circuit, so that the anti-interference capability of the circuit is improved, and the stability of the circuit is further improved.

Optionally, as shown in fig. 3, the constant-current constant-voltage charging circuit further includes a resistor R13, a resistor R14, and a resistor R15, an anode of an output end of the photocoupler U5 is sequentially connected to a feedback receiving pin of the feedback control end through a resistor R13 and a resistor R14, and a common end of the resistor R13 and the resistor R14 is connected to a capacitor discharging pin of the feedback control end through a resistor R15. The resistor R13 and the resistor R14 form a current-limiting branch, and the resistor R13 and the resistor R15 form a current-limiting branch for limiting the output current of the photoelectric coupler U5, so that the controller U6 is prevented from being burnt by overcurrent.

Optionally, as shown in fig. 3, the constant-current and constant-voltage charging circuit further includes a resistor R5, a resistor R11, a capacitor C1, and a capacitor C2, an output end of the comparator U1 is sequentially connected to an inverting input end of the comparator U1 through a resistor R5 and a capacitor C1, and an output end of the comparator U2 is sequentially connected to an inverting input end of the comparator U2 through a resistor R11 and a capacitor C2.

In the practical application of the comparator U1 and the comparator U2, the constant-current charging circuit and the constant-voltage charging circuit oscillate, which affects the stability of the charging signal and reduces the accuracy of the constant-current and constant-voltage control. In this embodiment, the resistor R5 and the capacitor C1 form a phase compensation circuit for performing phase compensation on the constant-voltage feedback loop, the resistor R11 and the capacitor C2 form a phase compensation circuit for performing phase compensation on the constant-current feedback loop, and the phase compensation branch can reduce the loop gain when the switching frequency of the circuit is high, ensure that the phase shift is kept unchanged when the switching frequency is very high, avoid oscillation of the negative feedback circuit, and further improve the accuracy of constant-current and constant-voltage control.

The above description is only a preferred embodiment of the present invention, and should not be taken as limiting the invention, and any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A1800W sealed lithium battery charging module comprises an LLC resonance conversion circuit and a constant-current constant-voltage charging circuit, and is characterized in that the constant-current constant-voltage charging circuit comprises a comparator U1, a comparator U2, a TL431 chip U3, a resistor R1, a resistor R2, a resistor R3 and a resistor R9; the positive electrode of the output end of the LLC resonant conversion circuit is grounded through a resistor R1 and a resistor R2 in sequence, the common end of the resistor R1 and the resistor R2 is connected with the inverting input end of a comparator U1, the positive electrode of the output end of the LLC resonant conversion circuit is grounded through a resistor R3, the cathode of a TL431 chip U3 and the anode of a TL431 chip U3 in sequence, the common ends of the resistor R3 and the TL431 chip U3 are connected with the non-inverting input end of the comparator U1, and the output end of the comparator U1 is connected with the feedback control end of a controller U6 of the LLC resonant conversion circuit; the reference pole of the TL431 chip U3 is connected with the non-inverting input end of the comparator U2, the negative pole of the output end of the LLC resonant conversion circuit is connected with the inverting input end of the comparator U2 through a resistor R9, and the output end of the comparator U2 is also connected with the feedback control end.

2. The 1800W sealed lithium battery charging module of claim 1, wherein the constant current and voltage charging circuit further comprises a diode D1, a diode D2; the diode D1 is connected between the output end of the comparator U1 and the feedback control end, the anode of the diode D1 is connected with the output end of the comparator U1, and the cathode of the diode D1 is connected with the feedback control end; the diode D2 is connected between the output end of the comparator U2 and the feedback control end, the anode of the diode D2 is connected with the output end of the comparator U2, and the cathode of the diode D2 is connected with the feedback control end.

3. The 1800W sealed lithium battery charging module of claim 1, wherein the constant current and voltage charging circuit further comprises a voltage follower U4, the voltage follower U4 is connected between the output terminal of the comparator U1 and the feedback control terminal.

4. The 1800W sealed lithium battery charging module of claim 1, wherein the constant current and voltage charging circuit further comprises a photo coupler U5, the positive terminal of the input terminal of the photo coupler U5 is connected to the positive terminal of the output terminal of the LLC resonant conversion circuit, the negative terminal of the input terminal of the photo coupler U5 is connected to the output terminal of the comparator U1 and the output terminal of the comparator U2, respectively, the positive terminal of the output terminal of the photo coupler U5 is connected to the feedback control terminal, and the negative terminal of the output terminal of the photo coupler U5 is grounded.

5. The 1800W sealed lithium battery charging module according to claim 4, wherein the photocoupler U5 is a PC817 chip.

6. The 1800W sealed lithium battery charging module of claim 4, wherein the constant-current constant-voltage charging circuit further comprises a resistor R13, a resistor R14 and a resistor R15, the positive electrode of the output terminal of the photocoupler U5 is connected with the feedback receiving pin of the feedback control terminal through a resistor R13 and a resistor R14 in sequence, and the common terminal of the resistor R13 and the resistor R14 is connected with the capacitor discharging pin of the feedback control terminal through a resistor R15.

7. The 1800W sealed lithium battery charging module as claimed in claim 1, wherein the constant current and voltage charging circuit further comprises a resistor R5, a resistor R11, a capacitor C1 and a capacitor C2, the output terminal of the comparator U1 is connected to the inverting input terminal of the comparator U1 through a resistor R5 and a capacitor C1 in sequence, and the output terminal of the comparator U2 is connected to the inverting input terminal of the comparator U2 through a resistor R11 and a capacitor C2 in sequence.

8. The 1800W sealed lithium battery charging module of claim 1, wherein the controller U6 is an L6599 chip.