CN205791691U - Multisection lithium battery uniform charging circuit - Google Patents

Abstract

The utility model discloses a multi-section lithium battery uniform charging circuit, which comprises a charging plug-in terminal and a lithium battery pack including three lithium battery cells, and a charging plug-in terminal and a positive pole of the lithium battery pack are provided with a The first one-way diode is also provided with a charging control circuit, an RC parallel detection circuit connected to the positive pole of the lithium battery cell, and a first drive circuit connected to the top lithium battery cell, and connected to the middle lithium battery cell The second drive circuit, the third drive circuit connected to the bottom lithium battery cell, the signal terminal of the first drive circuit, the control signal terminal of the second drive circuit, the signal terminal of the third drive circuit and the signal terminal of the charging control circuit connected controllers. The utility model has the advantages of simple structure and good use stability. The MCU control module can detect the voltage values of different battery cells, which is convenient for adjustment and control, and effectively buffers the imbalance caused by large current discharge to each cell of the battery pack.

Description

Multi-cell lithium battery uniform charging circuit

technical field

The utility model relates to the technical field of lithium battery pack charging circuits, in particular to a multi-section lithium battery uniform charging circuit.

Background technique

In electronic applications, often times the voltage required for the device to work does not match the voltage of the battery or the capacity is insufficient. Therefore, the battery will be connected in series or in parallel to reach the required voltage value or capacity. However, since the internal structure of each battery cannot be exactly the same, each battery will have a certain difference, the internal resistance of the battery is different, and the voltage value when fully charged is different.

For batteries connected in series, because the fully charged voltage value of each piece is different, if no adjustment is made, some batteries will be fully charged, while other parts of the batteries are still not fully charged. And this situation will have a great impact on the life of the battery in the long run. Especially for lithium batteries with relatively high requirements, it will have a greater impact.

Utility model content

The main purpose of the utility model is to provide a multi-cell lithium battery uniform charging circuit with simple structure and good conversion stability, aiming at effectively buffering the imbalance caused by large current discharge to each monomer of the battery pack.

The utility model proposes a multi-cell lithium battery uniform charging circuit, including a charging plug-in terminal and a lithium battery pack connected to the charging plug-in terminal and including three lithium battery cells. There is a first one-way diode between the positive pole and the positive pole of the lithium battery pack, and a charging control circuit, an RC parallel detection circuit connected to the positive pole of the lithium battery cell, and a first unidirectional diode connected to the top lithium battery cell. The drive circuit, the second drive circuit connected to the middle lithium battery cell, the third drive circuit connected to the bottom lithium battery cell, the signal terminal of the first drive circuit, the signal terminal of the second drive circuit, the third drive circuit A controller connected to both the signal terminal of the driving circuit and the signal terminal of the charging control circuit, the charging control circuit includes a first resistor, a second resistor, a first inductor, a first MOS transistor, a first triode, and a second unidirectional diode and the first capacitor, the drain of the first MOS transistor is connected to the anode of the charging terminal, the source is connected to the anode of the first unidirectional diode through the first inductance, and the gate is connected to the first unidirectional diode through the first resistor. On the collector of the triode, the emitter of the first triode is grounded, the second resistor is connected between the drain of the first MOS transistor and the gate of the first MOS transistor, and the first The capacitor is connected between the anode of the first unidirectional diode and the ground, the anode of the second unidirectional diode is connected to the ground and the cathode is connected to the anode of the first unidirectional diode, and the first triode The base is connected to the control signal terminal of the controller, and the detection signal terminal of the controller is connected to the connection point between the positive pole of the lithium battery cell and the RC parallel detection circuit.

The first drive circuit includes a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a second triode, a second MOS transistor and a third unidirectional diode, and the drain of the second MOS transistor is connected to On the positive pole of the lithium battery cell, the source is connected to the negative pole of the lithium battery cell through a third unidirectional diode, and the gate of the second MOS transistor is connected to the collector of the second triode through a third resistor Above, the emitter of the second triode is grounded, the fourth resistor is connected between the drain and the gate of the second MOS transistor, and the base of the second triode is connected to the The control signal end of the controller, one end of the sixth resistor is connected to the ground wire at the other end of the connection point between the fifth resistor and the control signal end of the controller.

The second drive circuit includes a tenth resistor, an eleventh resistor, a twelfth resistor, a thirteenth resistor, a fourteenth resistor, a fourth unidirectional diode, a fourth triode, and a third MOS transistor. The drain of the third MOS transistor is connected to the positive electrode of the middle lithium battery cell, the source of the third MOS transistor is connected to the negative electrode of the middle lithium battery cell through the tenth resistor and the fourth unidirectional diode, and the third MOS transistor is connected to the negative electrode of the middle lithium battery cell. The gate of the MOS transistor is connected to the collector of the fourth triode and the ground wire of the emitter of the fourth triode through the eleventh resistor, and the twelfth resistor is connected to the gate of the third MOS transistor and Between the drains, the base of the fourth triode is connected to the control signal terminal of the controller through the thirteenth resistor, and one end of the fourteenth resistor is connected between the thirteenth resistor and the control signal terminal of the controller Connect the other end to the ground wire at the point.

The third driving circuit includes a fifth unidirectional diode, a seventh resistor, an eighth resistor, a ninth resistor and a third triode, and the anode of the fifth unidirectional diode is connected to the lithium battery cell at the bottom end. positive pole, the negative pole of the fifth unidirectional diode is connected to the collector of the third triode through the seventh resistor, the emitter of the third triode is connected to the ground wire, and the base of the third triode The pole is connected to the control signal end of the controller through the eighth resistor, and one end of the ninth resistor is connected to the ground wire at the other end of the connection point between the eighth resistor and the control signal end of the controller.

The first MOS transistor, the second MOS transistor and the third MOS transistor are all P-type MOS transistors.

The first transistor, the second transistor, the third transistor and the fourth transistor are all NPN transistors.

The utility model is simple in structure and good in use stability. The MCU control module can detect the voltage values of different battery cells, which is convenient for adjustment and control, and effectively buffers the imbalance caused by large current discharge to each cell of the battery pack. Good stability, strong applicability and good practicability.

Description of drawings

Fig. 1 is the schematic diagram of the embodiment of the utility model.

The realization of the purpose of the utility model, functional characteristics and advantages will be further described in conjunction with the embodiments and with reference to the accompanying drawings.

detailed description

It should be understood that the specific embodiments described here are only used to explain the utility model, and are not intended to limit the utility model.

Referring to FIG. 1 , an embodiment of the present utility model is proposed, a multi-cell lithium battery uniform charging circuit, including a charging plug-in terminal 1 and a three-cell lithium battery cell 2 connected to the charging plug-in terminal 1 The lithium battery pack 3 is provided with a first unidirectional diode D1 between the positive pole of the charging plug terminal 1 and the positive pole of the lithium battery pack 3, and a charging control circuit 4 is also provided, which are respectively connected to the lithium battery cells 2 The RC parallel detection circuit 5 on the positive pole, the first drive circuit 6 connected to the top lithium battery cell, the second drive circuit 7 connected to the middle lithium battery cell, and the second drive circuit 7 connected to the bottom lithium battery cell Three drive circuits 8, a controller 9 connected to the signal terminal of the first drive circuit 6, the signal terminal of the second drive circuit 7, the signal terminal of the third drive circuit 8 and the signal terminal of the charging control circuit 4, the charging control circuit 4 includes The first resistor R1, the second resistor R2, the first inductor L1, the first MOS transistor Q1, the first triode Q2, the second unidirectional diode D2 and the first capacitor C1, the drain of the first MOS transistor Q1 It is connected to the anode of the charging plug terminal 1, the source is connected to the anode of the first unidirectional diode D1 through the first inductor L1, and the gate is connected to the collector of the first triode Q2 through the first resistor R1, The emitter ground line of the first triode Q2, the second resistor R2 is connected between the drain of the first MOS transistor Q1 and the gate of the first MOS transistor Q1, and the first capacitor C1 is connected to Between the anode of the first unidirectional diode D1 and the ground, the anode of the second unidirectional diode D2 is connected to the ground and the cathode is connected to the anode of the first unidirectional diode D1, and the first triode Q2 The base of the controller 9 is connected to the control signal end of the controller 9 and the detection signal end of the controller 9 is connected to the connection point between the positive electrode of the lithium battery cell 2 and the RC parallel detection circuit 5 .

The first drive circuit 6 includes a third resistor R3, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, a second triode Q3, a second MOS transistor Q4 and a third unidirectional diode D3. The drain of the second MOS transistor Q4 is connected to the positive electrode of the lithium battery cell 2, the source is connected to the negative electrode of the lithium battery cell 2 through the third unidirectional diode D3, and the gate of the second MOS transistor Q4 is connected to the negative electrode of the lithium battery cell 2 through the third unidirectional diode D3. The third resistor R3 is connected to the collector of the second transistor Q3, the emitter of the second transistor Q3 is grounded, and the fourth resistor R4 is connected between the drain and the gate of the second MOS transistor Q4 Between, the base of the second triode Q3 is connected to the control signal terminal of the controller 9 through the fifth resistor R5, and one end of the sixth resistor R6 is connected between the fifth resistor R5 and the control signal terminal of the controller 9 Connect the other end to the ground wire at the point.

The second drive circuit 7 includes a tenth resistor R10, an eleventh resistor R11, a twelfth resistor R12, a thirteenth resistor R13, a fourteenth resistor R14, a fourth unidirectional diode D4, and a fourth triode Q5 , the third MOS transistor Q6, the drain of the third MOS transistor Q6 is connected to the anode of the lithium battery cell 2 in the middle, and the source of the third MOS transistor Q6 passes through the tenth resistor R10 and the fourth one-way diode D4 Connected to the negative pole of the lithium battery cell 2 in the middle, the gate of the third MOS transistor Q6 is connected to the collector of the fourth transistor Q5 and the emitter of the fourth transistor Q5 through the eleventh resistor R11 grounding line, the twelfth resistor R12 is connected between the gate and the drain of the third MOS transistor Q6, and the base of the fourth triode Q5 is connected to the controller 9 through the thirteenth resistor R13 Signal end, one end of the fourteenth resistor R14 is connected to the connection point between the thirteenth resistor R13 and the control signal end of the controller 9 , and the other end is grounded.

The third drive circuit 8 includes a fifth unidirectional diode D5, a seventh resistor R7, an eighth resistor, R8, a ninth resistor R9, and a third triode Q7. The anode of the fifth unidirectional diode D5 is connected to the most The positive pole of the lithium battery cell 2 at the bottom end, the negative pole of the fifth unidirectional diode D5 is connected to the collector of the third triode Q7 through the seventh resistor R7, and the emitter of the third triode Q7 is connected to Ground wire, the base of the third triode Q7 is connected to the control signal terminal of the controller 9 through the eighth resistor R8, and one end of R9 of the ninth resistor is connected to the control signal terminal of the eighth resistor R8 and the controller 9 One end connection point on the other end ground wire.

The first MOS transistor, the second MOS transistor and the third MOS transistor are all P-type MOS transistors.

The first transistor, the second transistor, the third transistor and the fourth transistor are all NPN transistors.

In the attached figure, the connection points of the lithium battery monomer and the RC parallel detection circuit are BTV1, BTV2, and BTV3 respectively, which are the voltage detection points of the lithium battery. Through comparison, the voltage of each battery can be known, so as to know the charging status of the battery.

When it is detected that the battery is not fully charged, the transistor Q2 is turned on through the control signal P0 of the controller, so that the P-type MOS transistor Q1 is turned on, and the current flows to the three sets of batteries connected in series through the first unidirectional diode D1 Charge.

When it is detected that the voltage difference between BTV1 and BTV2 is equal to the full charge voltage of the lithium battery, the control signal P1 of the controller is at a high level, and the triode Q3 is turned on. Because the resistor R3 and the resistor R4 form a branch circuit, the two ends of the resistor R4 A voltage difference is formed, so that the P-type MOS transistor Q4 is turned on, and the main current passes through the MOS transistor Q4 and the diode D3 instead of passing through the BT1 terminal.

When it is detected that the voltage difference between BTV2 and BTV3 is equal to the full charge voltage of the lithium battery, the control signal terminal P2 of the controller is at a high level, and the triode Q5 is turned on. Because the resistor R12 and the resistor R11 form a branch circuit, the resistor R11 A voltage difference is formed at the terminals, so that the P-type MOS transistor Q6 is turned on, and the main current passes through the MOS transistor Q6, the resistor R10 and the diode D4. If the resistance value of R10 is set reasonably, the charging current will no longer pass through the BT2 terminal.

When it is detected that the voltage at BTV3 is equal to the full charge voltage of the lithium battery, the control signal terminal P3 of the controller is at a high level, the triode Q7 is turned on, and the main current passes through the triode Q7, resistor R7 and diode D5, and the resistance of R7 is set reasonably The value can make the charging current no longer pass through the BT1 terminal.

When it is detected that all the lithium batteries are fully charged, the control signal terminal P0 of the controller can be turned off, so that the triode Q2 is turned off, so that the P-type MOS transistor Q1 is turned off. When the detection voltage point of the lithium battery is lower than the full voltage point, the control signal terminal P0 of the controller can be turned on to charge the battery.

In the circuit, each group of lithium batteries has a corresponding detection voltage point and a lithium battery full processing circuit, so it can ensure that each group of lithium batteries is fully charged.

In the circuit, each group of lithium batteries is connected in parallel with a group of full-fill processing circuits, which can make the main current no longer pass through the group of lithium batteries after the group of batteries is fully charged, thus protecting the batteries.

In the circuit, the detection voltage point of each group of lithium batteries and the full-fill processing circuit are relatively independent. When connecting multiple groups of lithium batteries in series or in parallel or reducing the number of lithium battery groups in series, it only needs to be added or decreased reasonably.

The utility model is simple in structure and good in use stability. The MCU control module can detect the voltage values of different battery cells, which is convenient for adjustment and control, and effectively buffers the imbalance caused by large current discharge to each cell of the battery pack. Good stability, strong applicability and good practicability.

The above is only a preferred embodiment of the utility model, and does not limit the patent scope of the utility model. Any equivalent structure transformation made by using the specification of the utility model and the contents of the accompanying drawings, or directly or indirectly used in other related technologies Fields are all included in the scope of patent protection of the utility model in the same way.

Claims (6)

1. A multi-cell lithium battery uniform charging circuit, comprising a charging plug-in terminal and a lithium battery pack that is connected to the charging plug-in terminal and includes three lithium battery cells, and the positive electrode and the charging plug-in terminal are connected to each other. There is a first one-way diode between the positive poles of the lithium battery pack, and it is characterized in that: a charging control circuit is also provided, an RC parallel detection circuit connected to the positive pole of the lithium battery cell, and a RC parallel detection circuit connected to the top lithium battery cell The first drive circuit, the second drive circuit connected to the middle lithium battery cell, the third drive circuit connected to the bottom lithium battery cell, the signal terminal of the first drive circuit, and the control signal terminal of the second drive circuit , a controller connected to both the signal terminal of the third driving circuit and the signal terminal of the charging control circuit, the charging control circuit includes a first resistor, a second resistor, a first inductance, a first MOS tube, a first triode, a second A one-way diode and a first capacitor, the drain of the first MOS transistor is connected to the positive pole of the charging plug, the source is connected to the positive pole of the first one-way diode through the first inductor, and the gate is connected through the first resistor On the collector of the first triode, the emitter of the first triode is grounded, and the second resistor is connected between the drain of the first MOS transistor and the gate of the first MOS transistor, so The first capacitor is connected between the anode of the first unidirectional diode and the ground, the anode of the second unidirectional diode is connected to the ground and the cathode is connected to the anode of the first unidirectional diode, and the first three The base of the pole tube is connected to the control signal terminal of the controller, and the detection signal terminal of the controller is connected to the connection point between the positive pole of the lithium battery cell and the RC parallel detection circuit. 2. The multi-cell lithium battery uniform charging circuit according to claim 1, characterized in that: the first drive circuit includes a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a second triode, The second MOS tube and the third one-way diode, the drain of the second MOS tube is connected to the positive pole of the lithium battery cell, and the source is connected to the negative pole of the lithium battery cell through the third one-way diode, the said The gate of the second MOS transistor is connected to the collector of the second transistor through a third resistor, the emitter of the second transistor is grounded, and the fourth resistor is connected to the drain of the second MOS transistor and Between the gates, the base of the second triode is connected to the control signal terminal of the controller through the fifth resistor, and one end of the sixth resistor is connected to the connection point between the fifth resistor and the control signal terminal of the controller Ground wire on the other end. 3. The multi-cell lithium battery uniform charging circuit according to claim 2, characterized in that: the second drive circuit includes a tenth resistor, an eleventh resistor, a twelfth resistor, a thirteenth resistor, a fourteenth resistor resistance, a fourth unidirectional diode, a fourth triode, and a third MOS tube, the drain of the third MOS tube is connected to the positive pole of the middle lithium battery cell, and the source of the third MOS tube passes through the tenth The resistor and the fourth unidirectional diode are connected to the negative pole of the lithium battery cell in the middle, and the gate of the third MOS transistor is connected to the collector of the fourth transistor and the gate of the fourth transistor through the eleventh resistor. The emitter grounding line, the twelfth resistor is connected between the gate and the drain of the third MOS transistor, the base of the fourth triode is connected to the control signal terminal of the controller through the thirteenth resistor, One end of the fourteenth resistor is connected to the ground wire at the other end of the connection point between the thirteenth resistor and the control signal end of the controller. 4. The multi-cell lithium battery uniform charging circuit according to claim 3, characterized in that: the third driving circuit includes a fifth unidirectional diode, a seventh resistor, an eighth resistor, a ninth resistor and a third three-pole tube, the positive pole of the fifth one-way diode is connected to the positive pole of the bottommost lithium battery cell, the negative pole of the fifth one-way diode is connected to the collector of the third triode through the seventh resistor, and the The emitter of the third triode is connected to the ground wire, the base of the third triode is connected to the control signal terminal of the controller through the eighth resistor, and one end of the ninth resistor is connected between the eighth resistor and the controller The other end of the control signal terminal is connected to the ground wire. 5. The uniform charging circuit for multi-cell lithium batteries according to claim 4, wherein the first MOS transistor, the second MOS transistor and the third MOS transistor are all P-type MOS transistors. 6. The multi-cell lithium battery uniform charging circuit according to claim 5, characterized in that: the first triode, the second triode, the third triode and the fourth triode are all NPN type Triode.