CN211606149U - Charge and discharge protection circuit of lithium battery management system and lithium battery management system - Google Patents
Charge and discharge protection circuit of lithium battery management system and lithium battery management system Download PDFInfo
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- CN211606149U CN211606149U CN202020201335.0U CN202020201335U CN211606149U CN 211606149 U CN211606149 U CN 211606149U CN 202020201335 U CN202020201335 U CN 202020201335U CN 211606149 U CN211606149 U CN 211606149U
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
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- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/10—Energy storage using batteries
Abstract
The embodiment of the utility model discloses a lithium battery management system's charge-discharge protection circuit and lithium battery management system, this lithium battery management system's charge-discharge protection circuit includes first power supply circuit, starting circuit, DC/DC converting circuit, control circuit and voltage feedback circuit; the first power supply circuit is used for converting alternating-current voltage into direct-current voltage and outputting the direct-current voltage from an output end of the first power supply circuit; the voltage feedback circuit is used for feeding back the collected output voltage of the DC/DC conversion circuit to the control circuit, and the control circuit is used for regulating the driving control signal output to the input end of the DC/DC conversion circuit according to the output voltage of the DC/DC conversion circuit. The embodiment of the utility model provides a technical scheme has realized the protection of charging to the lithium cell, and circuit structure is simple, is favorable to reduce cost.
Description
Technical Field
The embodiment of the utility model provides a relate to power electronic technology field, especially relate to a lithium battery management system's charge-discharge protection circuit and lithium battery management system.
Background
Because of the advantages of small size, high energy density, no memory effect, long cycle life, high voltage, low self-discharge rate, etc., more and more products such as mobile phones, cameras, electric vehicles, bluetooth devices, etc. start to adopt lithium batteries as a main power source.
The lithium battery has certain risk in the charging and discharging process due to high energy density. When the lithium battery is in an overcharged state, the temperature of the lithium battery increases, which causes decomposition of an electrolyte inside the lithium battery to generate gas, so that the internal pressure of the lithium battery increases to break or catch fire. On the other hand, in the over-discharged state, the decomposition of the electrolyte deteriorates the charge/discharge characteristics and durability of the lithium battery, and the number of times of charging the lithium battery is reduced. Many poor lithium battery charging management systems are unreasonable in design, can cause the lithium cell to be in and take place danger under overcharge or overdischarge state, and safe reliability is lower.
SUMMERY OF THE UTILITY MODEL
An embodiment of the utility model provides a lithium battery management system's charge-discharge protection circuit and lithium battery management system to realize the charge-discharge protection of lithium cell.
In a first aspect, an embodiment of the present invention provides a charge and discharge protection circuit for a lithium battery management system, including: the power supply comprises a first power supply circuit, a starting circuit, a DC/DC conversion circuit, a control circuit and a voltage feedback circuit; the first power supply circuit comprises an input end, a first output end and a second output end, wherein the input end of the first power supply circuit is connected with an alternating-current voltage, and the first power supply circuit is used for converting the alternating-current voltage into a direct-current voltage and outputting the direct-current voltage from the output end of the first power supply circuit;
the starting circuit comprises an input end and an output end, the control circuit comprises a power supply end, a control end and a first input end, the input end of the starting circuit is electrically connected with the first output end of the first power supply circuit, and the output end of the starting circuit is electrically connected with the power supply end of the control circuit;
the DC/DC conversion circuit comprises an input end, an output end and a control end, wherein the input end of the DC/DC conversion circuit is electrically connected with the second output end of the first power supply circuit, the control end of the DC/DC conversion circuit is electrically connected with the control end of the control circuit, and the output end of the DC/DC conversion circuit is electrically connected with the lithium battery;
the voltage feedback circuit comprises an input end and an output end, the input end of the voltage feedback circuit is electrically connected with the output end of the DC/DC conversion circuit, the output end of the voltage feedback circuit is electrically connected with the first input end of the control circuit, the voltage feedback circuit is used for feeding back the collected output voltage of the DC/DC conversion circuit to the control circuit, and the control circuit is used for adjusting a driving control signal output to the input end of the DC/DC conversion circuit according to the output voltage of the DC/DC conversion circuit.
Optionally, the charge and discharge protection circuit of the lithium battery management system further includes a current feedback circuit, and the control circuit further includes a second input end;
the current feedback circuit comprises an input end and an output end, the input end of the current feedback circuit is electrically connected with the output end of the lithium battery, and the output end of the current feedback circuit is electrically connected with the second input end of the control circuit.
Optionally, the control circuit includes a control chip, and the control chip includes a power supply terminal, a signal output terminal, a current sampling terminal, and a voltage feedback terminal;
the power end of the control chip is electrically connected with the output end of the starting circuit, the signal output end of the control chip is electrically connected with the control end of the DC/DC conversion circuit, the current sampling end of the control chip is electrically connected with the output end of the current feedback circuit, and the voltage feedback end of the control chip is electrically connected with the output end of the voltage feedback circuit.
Optionally, the control circuit further includes a driving circuit;
the driving circuit comprises an input end and an output end, the input end of the driving circuit is electrically connected with the signal output end of the control chip, and the output end of the driving circuit is electrically connected with the control end of the DC/DC conversion circuit;
the driving circuit comprises a first capacitor, a first transformer and a first resistor, wherein the first transformer comprises a primary side and a secondary side; the first end of the first capacitor is electrically connected with the signal output end of the control chip, the second end of the first capacitor is electrically connected with the first end of the primary side of the first transformer, the second end of the primary side of the first transformer is grounded, and the secondary side of the first transformer is electrically connected with the control end of the DC/DC conversion circuit through a first resistor.
Optionally, the DC/DC conversion circuit includes a transistor, an inductor, a second capacitor, a first diode, and a second diode;
a first end of the transistor is electrically connected with a second end of the first resistor, a first end of the first resistor is electrically connected with a first end of a secondary side of the first transformer, a second end of the secondary side of the first transformer is electrically connected with a third end of the transistor, and a second end of the transistor is electrically connected with a second output end of the first power supply circuit;
the first end of the inductor is electrically connected with the third end of the transistor, the second end of the inductor is electrically connected with the input end of the lithium battery, the first end of the second capacitor is electrically connected with the second end of the inductor, and the second end of the second capacitor is grounded;
the first end of the first diode and the first end of the second diode are respectively and electrically connected with the first end of the inductor, and the second end of the first diode and the second end of the second diode are grounded.
Optionally, the current feedback circuit includes a second resistor, a third resistor, and a fourth resistor;
the first end of second resistance with the output electricity of lithium cell is connected, the second end of second resistance passes through the third resistance with control chip's current sample end electricity is connected, the first end of fourth resistance with the second end electricity of second resistance is connected, the second end ground connection of fourth resistance.
Optionally, the voltage feedback circuit includes a third diode, a fifth resistor, a sixth resistor, and a third capacitor;
the first end of the third diode is electrically connected with the second end of the inductor, the second end of the third diode is electrically connected with the voltage feedback end of the control chip through a fifth resistor, the first end of the third capacitor is electrically connected with the voltage feedback end of the control chip, the second end of the third capacitor is grounded, and the sixth resistor is connected with the third capacitor in parallel.
Optionally, the charge and discharge protection circuit of the lithium battery management system further includes a second power supply circuit;
the second power supply circuit comprises a second transformer, a fourth diode and a seventh resistor, and the second voltage device comprises a primary side and a secondary side;
the first end of the primary side of the second transformer is electrically connected with the third end of the transistor, the second end of the primary side of the second transformer is electrically connected with the first end of the inductor, the first end of the secondary side of the second transformer is electrically connected with the first end of the fourth diode, the second end of the fourth diode is electrically connected with the power supply end of the control chip through a seventh resistor, and the second end of the secondary side of the second transformer is grounded.
Optionally, the charge and discharge protection circuit of the lithium battery management system further includes a display circuit, the display circuit is electrically connected to the third input terminal of the control circuit, and the display circuit is configured to display charge and discharge parameters of the lithium battery.
In a second aspect, the embodiment of the utility model provides a lithium battery management system is still provided, include the utility model discloses the charge-discharge protection circuit of lithium battery management system that arbitrary embodiment provided.
The embodiment of the utility model provides a open control circuit through starting circuit, control circuit output drive signal control DC/DC converting circuit accomplishes transmission and the transform of energy, and voltage feedback circuit is through gathering DC/DC converting circuit's output voltage to feed back output voltage to control module, control module confirms the charged state of lithium cell according to received output voltage, and controls the break-make of lithium cell charging circuit through the drive signal who changes DC/DC converting circuit. The embodiment of the utility model provides a technical scheme is through adopting voltage feedback module to gather DC/DC converting circuit's output voltage and export to control circuit, and control circuit adjusts lithium battery charging circuit output voltage's stability through the drive signal who changes output to DC/DC converting circuit. Just the embodiment of the utility model provides a lithium battery management system's charge-discharge protection circuit simple structure can greatly reduce system's development cost.
Drawings
Fig. 1 is a schematic structural diagram of a charge and discharge protection circuit of a lithium battery management system according to an embodiment of the present invention;
fig. 2 is a schematic structural diagram of a charge and discharge protection circuit of another lithium battery management system according to an embodiment of the present invention;
fig. 3 is a schematic structural diagram of a charge/discharge protection circuit of another lithium battery management system according to an embodiment of the present invention;
fig. 4 is a schematic structural diagram of a charge/discharge protection circuit of another lithium battery management system according to an embodiment of the present invention;
fig. 5 is a schematic structural diagram of a charge/discharge protection circuit of another lithium battery management system according to an embodiment of the present invention;
fig. 6 is a schematic structural diagram of a charge/discharge protection circuit of another lithium battery management system according to an embodiment of the present invention;
fig. 7 is a schematic structural diagram of a charge and discharge protection circuit of another lithium battery management system according to an embodiment of the present invention.
Detailed Description
The present invention will be described in further detail with reference to the accompanying drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and are not limiting of the invention. It should be further noted that, for the convenience of description, only some of the structures related to the present invention are shown in the drawings, not all of the structures.
Fig. 1 is a schematic structural diagram of a charge and discharge protection circuit of a lithium battery management system according to an embodiment of the present invention. Referring to fig. 1, an embodiment of the present invention provides a charge and discharge protection circuit for a lithium battery management system, including: a first power supply circuit 10, a start-up circuit 20, a DC/DC conversion circuit 30, a control circuit 40, and a voltage feedback circuit 50;
the first power supply circuit 10 comprises an input end a1, a first output end a2 and a second output end A3, the input end a1 of the first power supply circuit 10 is connected with an alternating-current voltage, and the first power supply circuit 10 is used for converting the alternating-current voltage into a direct-current voltage and outputting the direct-current voltage from the output end;
the start-up circuit 20 comprises an input end B1 and an output end B2, the control circuit 40 comprises a power supply end E1, a control end E2 and a first input end E3, the input end B1 of the start-up circuit 20 is electrically connected with the first output end A2 of the first power supply circuit 10, and the output end B2 of the start-up circuit 20 is electrically connected with the power supply end E1 of the control circuit 40;
the DC/DC conversion circuit 30 comprises an input terminal F1, an output terminal F3 and a control terminal F2, the input terminal F1 of the DC/DC conversion circuit 30 is electrically connected to the second output terminal A3 of the first power supply circuit 10, the control terminal F2 of the DC/DC conversion circuit 30 is electrically connected to the control terminal E2 of the control circuit 40, and the output terminal F3 of the DC/DC conversion circuit 30 is electrically connected to the input terminal H1 of the lithium battery 60;
the voltage feedback circuit 50 comprises an input end G1 and an output end G2, the input end G1 of the voltage feedback circuit 50 is electrically connected with the output end F3 of the DC/DC conversion circuit 30, the output end G2 of the voltage feedback circuit 50 is electrically connected with the first input end E3 of the control circuit 40, the voltage feedback circuit 50 is used for feeding back the collected output voltage of the DC/DC conversion circuit 30 to the control circuit 40, and the control circuit 40 is used for regulating a driving control signal output to the input end F2 of the DC/DC conversion circuit 30 according to the output voltage of the DC/DC conversion circuit 30.
Specifically, the first power supply circuit 10 is configured to convert an ac voltage input from an input terminal a1 thereof into a DC voltage, and output the DC voltage from a first output terminal a2 and a second output terminal A3 thereof to the start circuit 20 and the DC/DC conversion circuit 30, respectively, so as to provide the DC/DC conversion circuit 30 with the power supply voltage. Illustratively, the first power supply circuit 10 may include a rectifier. The start-up circuit 20 is used to convert the voltage outputted from the first output terminal a2 of the first power supply circuit 10 into a voltage matched by the control circuit 40, so as to provide the start-up voltage for the control circuit 40. After the control circuit 40 normally operates, a driving signal is output to the DC/DC conversion circuit 30, and the DC/DC conversion circuit 30 outputs a stable DC voltage to charge the lithium battery 60 according to the received driving signal. When the output voltage of the DC/DC conversion circuit 30 is too high or too low, the output voltage of the DC/DC conversion circuit 30 is collected by the voltage feedback circuit 50 and output to the control circuit 40, and the control circuit 40 adjusts the output driving signal according to the output voltage of the DC/DC conversion circuit 30, so that the output voltage of the DC/DC conversion circuit 30 is stable to charge the lithium battery 60.
The embodiment of the utility model provides a open control circuit through starting circuit, control circuit output drive signal control DC/DC converting circuit accomplishes transmission and the transform of energy, and voltage feedback circuit is through gathering DC/DC converting circuit's output voltage to feed back output voltage to control module, control module confirms the charged state of lithium cell according to received output voltage, and controls the charging voltage's of lithium cell charging circuit size through the drive signal who changes DC/DC converting circuit. The embodiment of the utility model provides a technical scheme is through adopting voltage feedback module to gather DC/DC converting circuit's output voltage and export to control circuit, and control circuit adjusts lithium battery charging circuit output voltage's stability through the drive signal who changes output to DC/DC converting circuit, realizes the charge protection to lithium battery management system. Just the embodiment of the utility model provides a lithium battery management system's charge-discharge protection circuit simple structure can greatly reduce system's development cost.
Optionally, fig. 2 is a schematic structural diagram of a charge and discharge protection circuit of another lithium battery management system according to an embodiment of the present invention. Referring to fig. 2, on the basis of the above embodiment, the embodiment of the present invention provides a charge and discharge protection circuit for a lithium battery management system, further comprising: the current feedback circuit 70, the control circuit 40 further includes a second input terminal E4;
the current feedback circuit 70 comprises an input terminal I1 and an output terminal I2, the input terminal I1 of the current feedback circuit 70 is electrically connected with the output terminal H2 of the lithium battery 60, and the output terminal I2 of the current feedback circuit 70 is electrically connected with the second input terminal E4 of the control circuit 40.
Specifically, when the lithium battery 60 is in a discharging state, the current feedback circuit 70 collects the output current of the lithium battery 60, and when the lithium battery 60 is in an overcurrent or short circuit, the control circuit 40 stops outputting the driving signal by receiving the output current of the lithium battery 60 collected by the current feedback circuit 70, so as to turn off the charging loop of the lithium battery 60. And the current feedback circuit 70 and the voltage feedback circuit 50 form a voltage-current double closed-loop control, that is, a peak current feedback control is added in the voltage closed-loop control, and the control circuit 40 is used for realizing the turn-off or turn-on of the charging circuit of the lithium battery 60. The safety of the lithium battery 60 in the charging and/or discharging process can be effectively protected, and the reliability of the lithium battery management system is improved.
Optionally, fig. 3 is a schematic structural diagram of a charge and discharge protection circuit of another lithium battery management system according to an embodiment of the present invention. Referring to fig. 3, on the basis of the above embodiment, the control circuit 40 includes a control chip U1, the control chip U1 includes a power supply terminal 1, a signal output terminal 2, a current sampling terminal 3 and a voltage feedback terminal 4;
the power supply end 1 of the control chip U1 is electrically connected with the output end B2 of the starting circuit 20, the signal output end 2 of the control chip U1 is electrically connected with the control end F2 of the DC/DC conversion circuit 30, the current sampling end 3 of the control chip U1 is electrically connected with the output end I2 of the current feedback circuit 70, and the voltage feedback end 4 of the control chip U1 is electrically connected with the output end G2 of the voltage feedback circuit 50.
Specifically, the control chip U1 may be UC3845A, and is used for controlling the on/off state of the DC/DC conversion circuit 30. The start-up circuit 20 converts the voltage output from the first power supply circuit 10 into a voltage matched to the power supply terminal 1 of the control chip U1 to start up the control chip U1. The signal output end 2 of the control chip U1 outputs a driving signal to the DC/DC conversion circuit 30, and the DC/DC conversion circuit 30 outputs a DC voltage to charge the lithium battery. The voltage feedback circuit 50 collects the charging voltage output by the DC/DC conversion circuit 30, the current feedback circuit 70 collects the output current of the lithium battery 60, and the control chip U1 controls the duty ratio of the output driving signal by detecting the output voltage of the DC/DC conversion circuit 30 and the output current of the lithium battery 60, so as to adjust the charging voltage output by the DC/DC conversion circuit 30 to the lithium battery 60, so that the charging voltage of the lithium battery 60 is kept stable. When the lithium battery 60 is in an overcurrent or short circuit, the control chip U1 stops outputting the driving signal to control the charging circuit of the lithium battery 60 to be disconnected, so as to protect the load from being damaged by abnormal discharge of the lithium battery 60.
Optionally, on the basis of the above embodiment, with continued reference to fig. 3, the control circuit 40 further includes a driving circuit 410;
the driving circuit 410 comprises an input end and an output end, the input end of the driving circuit 410 is electrically connected with the signal output end 2 of the control chip U1, and the output end of the driving circuit 410 is electrically connected with the control end F2 of the DC/DC conversion circuit 30;
the driving circuit 410 includes a first capacitor C1, a first transformer T1, and a first resistor R1, where the first transformer T1 includes a primary side L1 and a secondary side L2; a first end of the first capacitor C1 is electrically connected to the signal output end 2 of the control chip U1, a second end of the first capacitor C1 is electrically connected to a first end of the primary side L1 of the first transformer T1, a second end of the primary side L1 of the first transformer T1 is grounded, and the secondary side L2 of the first transformer T1 is electrically connected to the control end F2 of the DC/DC conversion circuit 30 through a first resistor R1.
Specifically, the driving circuit 410 is configured to change a driving voltage of a driving signal output from the signal output terminal 2 of the control chip U1 through the first transformer T1 to drive the DC/DC conversion circuit 30 to normally operate, and the first transformer T1 also plays a role of electrical isolation to prevent pulse noise generated by the control chip U1 from interfering with the DC/DC conversion circuit 30.
Optionally, fig. 4 is a schematic structural diagram of a charge and discharge protection circuit of another lithium battery management system according to an embodiment of the present invention. Referring to fig. 4, on the basis of the above embodiment, the DC/DC conversion circuit 30 includes a transistor Q, an inductor L, a second capacitor C2, a first diode D1, and a second diode D2;
a first end of the transistor Q is electrically connected with a second end of the first resistor R1, a first end of the first resistor R1 is electrically connected with a first end of a secondary side L2 of the first transformer T1, a second end of a secondary side L1 of the first transformer T1 is electrically connected with a third end of the transistor Q, and a second end of the transistor Q is electrically connected with a second output end a3 of the first power supply circuit 10;
the first end of the inductor L is electrically connected with the third end of the transistor Q, the second end of the inductor L is electrically connected with the input end of the lithium battery 60, the first end of the second capacitor C2 is electrically connected with the second end of the inductor L, and the second end of the second capacitor C2 is grounded;
a first terminal of the first diode D1 and a first terminal of the second diode D2 are electrically connected to a first terminal of the inductor L, respectively, and a second terminal of the first diode D1 and a second terminal of the second diode D2 are grounded.
Specifically, the transistor Q is driven to be turned on after the first capacitor C1 and the first transformer T1 are coupled by a driving signal output by the signal output end 2 of the control chip U1, the output current of the transistor Q is filtered by the inductor L and the second capacitor C2 to supply power to the lithium battery 60, and the inductor L stores electric energy. When the transistor is turned off, since the current in the inductor L cannot abruptly change, the electric energy in the inductor L continues to output a smooth dc voltage to the lithium battery 60 through the first diode D1 and the second diode D2, wherein the first diode D1 and the second diode D2 are freewheeling diodes.
Optionally, fig. 5 is a schematic structural diagram of a charge and discharge protection circuit of another lithium battery management system according to an embodiment of the present invention. Referring to fig. 5, on the basis of the above embodiment, the current feedback circuit 70 includes the second resistor R2, the third resistor R3, and the fourth resistor R4;
the first end of the second resistor R2 is electrically connected to the output terminal H2 of the lithium battery 60, the second end of the second resistor R2 is electrically connected to the current sampling terminal 3 of the control chip U1 through the third resistor R3, the first end of the fourth resistor R4 is electrically connected to the second end of the second resistor R2, and the second end of the fourth resistor R4 is grounded.
Specifically, the second resistor R2, the third resistor R3 and the fourth resistor R4 are sampling resistors, the output current of the lithium battery 60 is fed back to the current sampling terminal 3 of the control chip U1 through the second resistor R2, the third resistor R3 and the fourth resistor R4, and the control chip U1 determines the discharge state of the lithium battery 60 by receiving the sampling current. For example, when the lithium battery 60 is in an overcurrent or short circuit, the output current of the lithium battery 60 may suddenly increase, and at this time, the control chip U1 may control the transistor Q to turn off, so as to disconnect the charging loop of the lithium battery 60 and protect the safe operation of the lithium battery management system. When the output current of the lithium battery 60 is lower than the normal value, it can be determined that the lithium battery 60 is in an over-discharge state, and the control chip U1 turns on the transistor Q in time to turn on the charging loop of the lithium battery 60 to charge the lithium battery 60. The charging and discharging states of the lithium battery 60 can be effectively monitored through the control circuit 40, so that the safe operation of a lithium battery charging loop is ensured, and the safety and reliability of a lithium battery management system are improved.
Optionally, on the basis of the above embodiment, with continued reference to fig. 5, the voltage feedback circuit 50 includes a third diode D3, a fifth resistor R5, a sixth resistor R6, and a third capacitor C3;
a first end of the third diode D3 is electrically connected to a second end of the inductor L, a second end of the third diode D3 is electrically connected to a voltage feedback end 4 of the control chip U1 through a fifth resistor R5, a first end of the third capacitor C3 is electrically connected to the voltage feedback end 4 of the control chip U1, a second end of the third capacitor C3 is grounded, and the sixth resistor R6 is connected in parallel to the third capacitor C3.
Specifically, the voltage feedback circuit 50 is specifically configured to collect the output voltage of the DC/DC conversion circuit 30, and feed back the collected output voltage to the voltage feedback terminal 4 of the control chip U1, and the control chip U1 determines the charging state of the lithium battery 60 according to the received output voltage. If the output voltage of the DC/DC conversion circuit 30 is too high or too low, the control chip U1 adjusts the duty ratio of the driving signal output by the signal output terminal 2 to adjust the output voltage of the DC/DC conversion circuit 30 to be constant, so as to ensure the charging voltage of the lithium battery 60 to be stable and improve the charging reliability of the lithium battery 60.
Optionally, fig. 6 is a schematic structural diagram of a charge and discharge protection circuit of another lithium battery management system according to an embodiment of the present invention. Referring to fig. 6, on the basis of the above embodiment, the embodiment of the present invention provides a charge and discharge protection circuit for a lithium battery management system, further comprising: a second power supply circuit 80;
the second power circuit 80 comprises a second transformer T2, a fourth diode D4 and a seventh resistor R7, and the second transformer T2 comprises a primary side L3 and a secondary side L4;
a first end of a primary side L3 of the second transformer T2 is electrically connected to the third end of the transistor Q, a second end of a primary side L3 of the second transformer T2 is electrically connected to a first end of the inductor L, a first end of a secondary side L4 of the second transformer T2 is electrically connected to a first end of a fourth diode D4, a second end of the fourth diode D4 is electrically connected to a power supply terminal of the control chip through a seventh resistor R7, and a second end of a secondary side L4 of the second transformer T2 is grounded.
Specifically, the ac voltage output by the transistor Q is applied to the primary side L3 of the second transformer T2, the secondary side L4 of the second transformer T2 generates a converted voltage by sensing the voltage on the primary side L3, and the converted voltage is rectified into a dc voltage by the diode D4 to provide a power supply voltage for the control chip U1, and the seventh resistor R7 plays a role in limiting the current. Since the impedance of the second power circuit 80 is smaller than the impedance of the starting circuit 10, only the second power circuit 80 provides the power voltage for the control chip U1 during the normal operation of the charge and discharge protection circuit of the lithium battery management system.
Optionally, on the basis of the foregoing embodiment, continuously refer to fig. 6, the embodiment of the present invention provides a charging and discharging protection circuit for a lithium battery management system, further including a display circuit 90, for displaying status parameters of the lithium battery management system under various operating statuses. Illustratively, the display circuit may employ a liquid crystal display module.
Optionally, fig. 7 is a schematic structural diagram of a charge and discharge protection circuit of another lithium battery management system according to an embodiment of the present invention. Referring to fig. 7, an embodiment of the present invention provides a specific working principle of a charge and discharge protection circuit of a lithium battery management system as follows:
the first power supply circuit 10 converts an ac voltage input from an input terminal a1 thereof into a DC voltage, and outputs the DC voltage from a first output terminal a2 and a second output terminal A3 thereof to the starter circuit 20 and the DC/DC converter circuit 30, respectively, to supply the DC/DC converter circuit 30 with the power supply voltage. The start-up circuit 20 may include a fifth diode D5 and an eighth resistor R8, which are used to limit the current output by the first power circuit 10 and prevent the control chip U1 from being burned due to excessive current. The starting circuit controls the on-off of the charging and discharging protection circuit of the whole lithium battery management system, and when the charging and discharging protection circuit of the lithium battery management system works normally, the impedance of the second power supply circuit 80 is smaller than that of the starting circuit 10, so that in the normal working process of the charging and discharging protection circuit of the lithium battery management system, only the second power supply circuit 80 provides power supply voltage for the control chip U1. After the control chip U1 is turned on, the output driving signal provides a driving signal to the transistor Q via the first capacitor C1 and the first transformer T1. The output current of the transistor Q is filtered by the inductor L and the second capacitor C2 to supply power to the lithium battery 60, and the inductor L stores electric energy. When the transistor is turned off, since the current in the inductor L cannot abruptly change, the electric power in the inductor L continues to output a smooth dc voltage to the lithium battery 60 through the first diode D1 and the second diode D2. The voltage feedback circuit 50 collects the charging voltage output by the DC/DC conversion circuit 30, and compares the collected output voltage with the reference voltage in the control chip U1, and then changes the duty ratio of the driving signal output by the signal output terminal 2 to adjust the charging voltage output by the DC/DC conversion circuit 30 to the lithium battery 60, so that the charging voltage of the lithium battery 60 is kept stable. The current feedback circuit 70 collects the output current of the lithium battery 60, when the lithium battery 60 is in overcurrent or short circuit, the voltage of the signal output end 2 of the control chip U1 is increased, the duty ratio of the driving signal is controlled to turn off the transistor, and the charging loop of the lithium battery 60 is controlled to be disconnected, so that the damage of abnormal discharge of the lithium battery 60 to the load is protected.
The output voltage of the DC/DC conversion circuit 30 can be adjusted to any voltage value of 0-48V by adjusting the fifth resistor R5, the sixth diode D6 and the second capacitor C2. To ensure the safety of the transistor Q, the voltage output from the second output terminal a3 of the first power supply circuit 10 does not exceed 48V. Of course, in other embodiments, the level of the input voltage of the DC/DC converter circuit 30 can be increased by selecting the transistor Q having a high withstand voltage value.
The embodiment of the utility model provides a open control circuit through starting circuit, control circuit output drive signal control DC/DC converting circuit accomplishes transmission and the transform of energy, and voltage feedback circuit is through gathering DC/DC converting circuit's output voltage to feed back output voltage to control module, control module confirms the charged state of lithium cell according to received output voltage, and controls the charging voltage's of lithium cell charging circuit size through the drive signal who changes DC/DC converting circuit. The embodiment of the utility model provides a technical scheme is through adopting voltage feedback module to gather DC/DC converting circuit's output voltage and export to control circuit, and control circuit adjusts lithium battery charging circuit output voltage's stability through the drive signal who changes output to DC/DC converting circuit, realizes the charge protection to lithium battery management system. When the lithium battery is in overcurrent or short circuit, the output current of the lithium battery can be suddenly increased, and at the moment, the control chip can control the transistor to be switched off so as to disconnect the charging circuit of the lithium battery and protect the safe operation of the lithium battery management system. When the output current of the lithium battery is lower than a normal value, the lithium battery can be determined to be in an over-discharge state, and the control chip switches on the transistor in time so as to switch on a charging loop of the lithium battery and charge the lithium battery. The charging and discharging states of the lithium battery can be effectively monitored through the control circuit, so that the safe operation of a lithium battery charging loop is ensured, and the safety and reliability of the lithium battery management system are improved. Just the embodiment of the utility model provides a lithium battery management system's charge-discharge protection circuit simple structure can greatly reduce system's development cost.
The embodiment of the utility model provides a lithium battery management system is still provided, include the utility model discloses the charge-discharge protection circuit of lithium battery management system that arbitrary embodiment provided can realize monitoring the charge-discharge process of lithium cell to improve the life of lithium cell. The embodiment of the utility model provides a lithium battery management system includes the charge-discharge protection circuit of the lithium battery management system in the above-mentioned embodiment, consequently the embodiment of the utility model provides a lithium battery management system also possesses the beneficial effect that the above-mentioned embodiment described.
It should be noted that the foregoing is only a preferred embodiment of the present invention and the technical principles applied. It will be understood by those skilled in the art that the present invention is not limited to the particular embodiments described herein, but is capable of various obvious changes, rearrangements and substitutions as will now become apparent to those skilled in the art without departing from the scope of the invention. Therefore, although the present invention has been described in greater detail with reference to the above embodiments, the present invention is not limited to the above embodiments, and may include other equivalent embodiments without departing from the scope of the present invention.
Claims (10)
1. A charge and discharge protection circuit of a lithium battery management system is characterized by comprising: the power supply comprises a first power supply circuit, a starting circuit, a DC/DC conversion circuit, a control circuit and a voltage feedback circuit;
the first power supply circuit comprises an input end, a first output end and a second output end, wherein the input end of the first power supply circuit is connected with an alternating-current voltage, and the first power supply circuit is used for converting the alternating-current voltage into a direct-current voltage and outputting the direct-current voltage from the output end of the first power supply circuit;
the starting circuit comprises an input end and an output end, the control circuit comprises a power supply end, a control end and a first input end, the input end of the starting circuit is electrically connected with the first output end of the first power supply circuit, and the output end of the starting circuit is electrically connected with the power supply end of the control circuit;
the DC/DC conversion circuit comprises an input end, an output end and a control end, wherein the input end of the DC/DC conversion circuit is electrically connected with the second output end of the first power supply circuit, the control end of the DC/DC conversion circuit is electrically connected with the control end of the control circuit, and the output end of the DC/DC conversion circuit is electrically connected with the lithium battery;
the voltage feedback circuit comprises an input end and an output end, the input end of the voltage feedback circuit is electrically connected with the output end of the DC/DC conversion circuit, the output end of the voltage feedback circuit is electrically connected with the first input end of the control circuit, the voltage feedback circuit is used for feeding back the collected output voltage of the DC/DC conversion circuit to the control circuit, and the control circuit is used for adjusting a driving control signal output to the input end of the DC/DC conversion circuit according to the output voltage of the DC/DC conversion circuit.
2. The charging and discharging protection circuit of the lithium battery management system according to claim 1, further comprising a current feedback circuit, wherein the control circuit further comprises a second input terminal;
the current feedback circuit comprises an input end and an output end, the input end of the current feedback circuit is electrically connected with the output end of the lithium battery, and the output end of the current feedback circuit is electrically connected with the second input end of the control circuit.
3. The charging and discharging protection circuit of the lithium battery management system according to claim 2, wherein the control circuit comprises a control chip, and the control chip comprises a power supply terminal, a signal output terminal, a current sampling terminal and a voltage feedback terminal;
the power end of the control chip is electrically connected with the output end of the starting circuit, the signal output end of the control chip is electrically connected with the control end of the DC/DC conversion circuit, the current sampling end of the control chip is electrically connected with the output end of the current feedback circuit, and the voltage feedback end of the control chip is electrically connected with the output end of the voltage feedback circuit.
4. The charging and discharging protection circuit of a lithium battery management system according to claim 3, wherein the control circuit further comprises a driving circuit;
the driving circuit comprises an input end and an output end, the input end of the driving circuit is electrically connected with the signal output end of the control chip, and the output end of the driving circuit is electrically connected with the control end of the DC/DC conversion circuit;
the driving circuit comprises a first capacitor, a first transformer and a first resistor, wherein the first transformer comprises a primary side and a secondary side; the first end of the first capacitor is electrically connected with the signal output end of the control chip, the second end of the first capacitor is electrically connected with the first end of the primary side of the first transformer, the second end of the primary side of the first transformer is grounded, and the secondary side of the first transformer is electrically connected with the control end of the DC/DC conversion circuit through a first resistor.
5. The charging and discharging protection circuit of the lithium battery management system according to claim 4, wherein the DC/DC conversion circuit comprises a transistor, an inductor, a second capacitor, a first diode and a second diode;
a first end of the transistor is electrically connected with a second end of the first resistor, a first end of the first resistor is electrically connected with a first end of a secondary side of the first transformer, a second end of the secondary side of the first transformer is electrically connected with a third end of the transistor, and a second end of the transistor is electrically connected with a second output end of the first power supply circuit;
the first end of the inductor is electrically connected with the third end of the transistor, the second end of the inductor is electrically connected with the input end of the lithium battery, the first end of the second capacitor is electrically connected with the second end of the inductor, and the second end of the second capacitor is grounded;
the first end of the first diode and the first end of the second diode are respectively and electrically connected with the first end of the inductor, and the second end of the first diode and the second end of the second diode are grounded.
6. The charging and discharging protection circuit of the lithium battery management system according to claim 5, wherein the current feedback circuit comprises a second resistor, a third resistor and a fourth resistor;
the first end of second resistance with the output electricity of lithium cell is connected, the second end of second resistance passes through the third resistance with control chip's current sample end electricity is connected, the first end of fourth resistance with the second end electricity of second resistance is connected, the second end ground connection of fourth resistance.
7. The charging and discharging protection circuit of the lithium battery management system according to claim 5, wherein the voltage feedback circuit comprises a third diode, a fifth resistor, a sixth resistor and a third capacitor;
the first end of the third diode is electrically connected with the second end of the inductor, the second end of the third diode is electrically connected with the voltage feedback end of the control chip through a fifth resistor, the first end of the third capacitor is electrically connected with the voltage feedback end of the control chip, the second end of the third capacitor is grounded, and the sixth resistor is connected with the third capacitor in parallel.
8. The charging and discharging protection circuit of a lithium battery management system according to claim 5, further comprising a second power supply circuit;
the second power supply circuit comprises a second transformer, a fourth diode and a seventh resistor, and the second voltage device comprises a primary side and a secondary side;
the first end of the primary side of the second transformer is electrically connected with the third end of the transistor, the second end of the primary side of the second transformer is electrically connected with the first end of the inductor, the first end of the secondary side of the second transformer is electrically connected with the first end of the fourth diode, the second end of the fourth diode is electrically connected with the power supply end of the control chip through a seventh resistor, and the second end of the secondary side of the second transformer is grounded.
9. The charging and discharging protection circuit of the lithium battery management system according to claim 1, further comprising a display circuit, wherein the display circuit is electrically connected to a third input terminal of the control circuit, and the display circuit is configured to display charging and discharging parameters of the lithium battery.
10. A lithium battery management system comprising the charge and discharge protection circuit of the lithium battery management system according to any one of claims 1 to 9.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202020201335.0U CN211606149U (en) | 2020-02-24 | 2020-02-24 | Charge and discharge protection circuit of lithium battery management system and lithium battery management system |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202020201335.0U CN211606149U (en) | 2020-02-24 | 2020-02-24 | Charge and discharge protection circuit of lithium battery management system and lithium battery management system |
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| CN211606149U true CN211606149U (en) | 2020-09-29 |
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Effective date of registration: 20201208 Address after: 435000 plant 2, No.289 Shengshui Road, Jinshan Street office, Huangshi economic and Technological Development Zone, Huangshi City, Hubei Province Patentee after: Huangshi Zhongxing paineng Energy Technology Co., Ltd Address before: 201203 Shanghai City, Pudong New Area China Zuchongzhi Road (Shanghai) Free Trade Zone No. 73 Lane 887 Patentee before: PYLON TECHNOLOGIES Co.,Ltd. |
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