CN110571883A - Lithium battery charging current limiting system - Google Patents
Lithium battery charging current limiting system Download PDFInfo
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- CN110571883A CN110571883A CN201910853388.2A CN201910853388A CN110571883A CN 110571883 A CN110571883 A CN 110571883A CN 201910853388 A CN201910853388 A CN 201910853388A CN 110571883 A CN110571883 A CN 110571883A
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- current limiting
- lithium battery
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
- H02J7/0029—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries with safety or protection devices or circuits
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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
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- 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 invention discloses a lithium battery charging current limiting system, which is provided with a BMS (battery management system) connected with a lithium battery pack, wherein the BMS comprises a positive charging wire, a negative charging wire, an MCU (microprogrammed control unit), a charging current detection circuit, a current limiting circuit, a first switching circuit and a current divider. The charging current detection circuit detects the current through the current divider and outputs signals to the MCU and the first switch circuit; the MCU receives a signal from the charging current detection circuit and then determines the on and off of the first switch circuit and the current limiting circuit according to the signal. The invention solves the problem that the current of the lithium battery system is overlarge in the charging and discharging process, greatly improves the performance and the use safety of the lithium battery system, has good operability and flexibility, and is suitable for batch production.
Description
Technical Field
The invention relates to the technical field of battery management, in particular to a lithium battery charging current limiting system.
background
With the application and development of the lithium battery system in the application fields of household energy storage, industrial and commercial energy storage, distributed energy storage and the like, people put forward higher demands on the standby energy of the battery pack of the lithium battery system. When the capacity of the energy storage system is expanded, although the pressure difference between the two battery packs is small when the traditional lithium battery system is connected in parallel, because the internal resistance of the lithium battery is small, a large balance current can be generated between the battery packs. When capacity expansion and parallel connection are carried out, in order to solve the problem of overlarge balance, capacity and voltage of each battery system can be matched and matched to carry out capacity expansion at the initial stage of system installation or the output condition of a plurality of lithium battery systems can be controlled only by communication and communication among batteries, but the flexibility and operability of the battery system module are greatly reduced.
Similarly, when the lithium battery system is charged, too large charging current is easily generated due to small internal resistance, overcurrent protection or short-circuit protection and the like are easily generated, the service life of the battery pack is seriously influenced, and safety problems such as fire and explosion can even occur.
disclosure of Invention
The invention mainly aims to provide a lithium battery charging current limiting system to solve the problem that excessive current is generated when lithium battery systems are connected in parallel or charged.
The invention provides the following technical scheme:
The utility model provides a lithium battery charging current limiting system, has the BMS who links to each other with lithium cell group, BMS contains anodal charging wire, negative pole charging wire, MCU, charging current detection circuit, current limiting circuit, first switch circuit and shunt.
The first end of anodal charging wire is used for connecting the positive pole of lithium cell group, and the anodal input of BMS is connected to the second end of anodal charging wire.
The first end of negative pole charging wire is used for connecting the negative pole of lithium cell group, and the negative pole input of BMS is held to the second of negative pole charging wire.
the shunt and the first switch circuit are arranged on the negative charging wire in series; the current divider is located between the first switching circuit and the first end of the negative charging wire.
The current limiting circuit has a first terminal connected to the negative input terminal of the BMS and a second terminal connected to a negative charge line between the shunt and the first switching circuit.
The charging current detection circuit collects the charging current of the negative charging wire through the shunt and sends a signal to the MCU and the first switch circuit.
The MCU receives the signals sent by the charging current detection circuit and then sends corresponding signals to control the on and off of the first switch circuit and the current limiting circuit.
When the lithium battery system normally operates, the MCU outputs a control signal S3 to control the conduction of the first switch circuit; the current limiting circuit is in an off state. The normal operation of the lithium battery system refers to the condition that the charging current is smaller than a preset value.
When the charging current detection circuit detects that the charging current is larger than the preset value, the charging current detection circuit outputs a signal S4 to the first switch circuit to disconnect the first switch circuit and outputs an overcurrent signal S1 to the MCU; the MCU receives the overcurrent signal S1, turns off the signal S3, and outputs a signal S2 to the current limiting circuit to start the current limiting circuit.
When the charging current detection circuit detects that the charging current is smaller than the preset value, the charging current detection circuit turns off a signal S4 and an overcurrent signal S1; the MCU retransmits the S3 signal to turn on the first switch circuit and turn off the S2 signal to turn off the current limiting circuit.
Further, the current limiting circuit includes a second switch circuit, an inductor L1, a MOS transistor Q1, a resistor R1, and a resistor R2.
The second switch circuit, the resistor R2, the inductor L1, the MOS transistor Q1 and the resistor R1 are arranged in series; one end of the second switch circuit is connected to a negative charging line between the first switch circuit and the shunt; one end of the resistor R1 is connected with the negative input end of the BMS; the resistor R2 is positioned between the second switch circuit and the inductor L1; the MOS transistor Q1 is located between the inductor L1 and the resistor R1.
When the lithium battery system normally operates, the second switch circuit is in a disconnected state, and when the charging current is larger than the preset value, the MCU sends a signal S2 to the second switch circuit to enable the second switch circuit to be switched on, so that the whole current limiting circuit is started.
Further, the current limiting circuit further comprises a resistor R3, a resistor R4, a capacitor C1 and a capacitor C2.
One end of the resistor R3 is connected with the resistor R4, and the other end of the resistor R3 is connected with the positive input end of the BMS; one end of the resistor R4 is connected with the resistor R3, and the other end is connected with an electric wire between the second switch circuit and the resistor R2; one end of the capacitor C1 is connected with the positive input end of the BMS, and the other end is connected with the wire between the resistor R2 and the inductor L1; and two ends of the capacitor C2 are respectively connected with the positive and negative input ends of the BMS.
Further, the current limiting circuit also comprises a control circuit.
The control circuit adjusts PWM and outputs duty ratio by detecting the voltage division of the current resistor R3 and the resistor R4, the current on the resistor R2 and the peak current on the resistor R1, and further controls the on and off of the MOS transistor Q1 to limit the output current of the whole current limiting circuit.
further, the current limiting circuit further includes a freewheeling diode D1.
The anode of the freewheeling diode D1 is connected to the line between the inductor L1 and the MOS transistor Q1, and the cathode is connected to the positive input terminal of the BMS.
When the MOS transistor Q1 is conducted, a part of energy is transmitted to the inductor L1, and meanwhile, a part of energy is used for charging the lithium battery pack; when the MOS transistor Q1 is turned off, the energy stored in the inductor L1 continues to charge the lithium battery through the freewheeling diode D1.
Further, the BMS includes a fuse F1, and the fuse F1 is connected in series to the positive charging wire.
Further, the BMS may further include a fuse F2, and the fuse F2 may have one end connected to the second switching circuit and one end connected to a negative charging line between the first switching circuit and the shunt.
further, the charging current detection circuit includes an amplifier and a comparison latch.
The amplifier collects the charging current on the current divider, amplifies the current signal and outputs the amplified current signal to the comparison latch; the comparison latch compares the received current signal with a preset value.
further, the BMS also comprises an AFE, and the AFE samples the temperature of the lithium battery pack and sends a signal to the MCU.
Further, 2 temperature thresholds are set on the AFE, which are respectively a threshold X and a threshold Y; the threshold value X is smaller than the threshold value Y.
When the temperature of the lithium battery pack collected by the AFE is greater than the threshold value X and less than the threshold value Y, a signal S5 is sent to the MCU, the MCU closes the signal S3, and simultaneously outputs a signal S2 to the current limiting circuit to start the current limiting circuit.
When the temperature of the lithium battery pack collected by the AFE is larger than the threshold value Y, the AFE outputs a signal S6 to the MCU, the MCU closes signals S2 and S3, and the current limiting circuit and the first switch circuit are disconnected.
according to the invention, the charging current-limiting loop is additionally arranged in the lithium battery system, so that the lithium battery system has a current-limiting function, and the functions of the lithium battery system are improved and the lithium battery system is protected. Meanwhile, devices and circuits adopted in the charging current limiting system are common mature currents, the cost is low, the current limiting design is completely carried out according to a lithium battery system, the charging current limiting system is completely and independently controlled, the parallel connection form of battery modules is not limited, and the installation operability and flexibility are greatly enhanced. In system maintenance, if a battery module needs to be replaced or added, the battery module can be connected in parallel at will without being limited to the communication form or the electric quantity of the battery module, and the system is high in maintainability and suitable for batch production.
Drawings
Fig. 1 is a schematic structural diagram of an embodiment of a current limiting system for charging a lithium battery according to the present invention;
Fig. 2 is a schematic circuit diagram of an embodiment of a current limiting system for charging a lithium battery according to the present invention.
The implementation, functional features and advantages of the objects of the present invention will be further explained with reference to the accompanying drawings.
Detailed Description
It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
In addition, technical solutions between various embodiments may be combined with each other, but must be realized by a person skilled in the art, and when the technical solutions are contradictory or cannot be realized, such a combination should not be considered to exist, and is not within the protection scope of the present invention.
The first embodiment is as follows:
Fig. 1 is a schematic structural diagram of a lithium battery charging current limiting system according to the present invention, and fig. 2 is a schematic circuit diagram of the lithium battery charging current limiting system according to the present invention. The embodiment can be suitable for the condition of current limiting during lithium battery charging.
Referring to fig. 1, a current limiting System for charging a lithium battery includes a BMS (battery Management System) 1 connected to a lithium battery pack, and a BMS1 includes a positive charging line 105, a negative charging line 106, an MCU (MicroControl Unit MCU), a charging current detecting circuit 102, a current limiting circuit 103, a first switching circuit 104, and a current divider 101.
The first end of anodal charging wire 105 is used for connecting the positive pole of lithium cell group, and the anodal input of BMS1 is connected to the second end of anodal charging wire 105.
the first end of negative pole charging wire 106 is used for connecting the negative pole of lithium cell group, and the negative pole input of BMS1 is connected to the second end of negative pole charging wire 106.
The shunt 101 and the first switching circuit 104 are arranged in series on a negative charging line 106; the current divider 101 is located between the first switching circuit 104 and a first end of a negative charging line 106.
Current limiting circuit 103 has a first terminal connected to the negative input of BMS1 and a second terminal connected to negative charging line 106 between shunt 101 and first switching circuit 104.
The charging current detection circuit 102 collects the charging current of the negative charging wire 106 through the shunt 101 and sends a signal to the MCU and the first switching circuit 104.
The MCU controls the on and off of the first switch circuit 104 and the current limiting circuit 103 by receiving the signal transmitted from the charging current detection circuit 102 and then transmitting a corresponding signal.
When the lithium battery system normally operates, the MCU outputs a control signal S3 to control the first switch circuit 104 to be conducted; the current limiting circuit 103 is in an off state.
When the charging current detection circuit 102 detects that the charging current is greater than the preset value, the charging current detection circuit 102 outputs a signal S4 to the first switch circuit 104 to turn off the first switch circuit 104, and outputs an overcurrent signal S1 to the MCU; the MCU receives the over-current signal S1, turns off the signal S3, and outputs a signal S2 to the current limiting circuit 103 to turn on the current limiting circuit 103.
When the charging current detection circuit 102 detects that the charging current is smaller than the preset value, the charging current detection circuit 102 turns off the signal S4 and the overcurrent signal S1; the MCU resends the S3 signal to turn on the first switch circuit 104 and turn off the S2 signal to turn off the current limit circuit 103.
When the battery is charged and the charging current is smaller than the preset value, the direction of the current is as follows: flows from the positive pole BATT + of the battery to the negative pole BATT-, then passes through the shunt 101, the first switch circuit 104, the negative pole input end P-/C-of the BMS1, and the positive pole input end P +/C + of the BMS1, and finally flows to the positive pole BATT + of the battery.
When the battery is charged and the charging current is greater than the predetermined value, the system will switch off the first switch circuit 104 and switch on the current limiting circuit 103, so the current direction is: flows from the positive pole BATT + of the battery to the negative pole BATT-, then passes through the shunt 101, the current limiting circuit 103, the negative pole input end P-/C-of the BMS1, and the positive pole input end P +/C + of the BMS1, and finally flows to the positive pole BATT + of the battery. The charging current decreases towards the preset value through the current limiting loop until it is stable.
The first switch circuit 104 may be composed of a MOS transistor having a source connected to the negative input terminal P-/C of the BMS1, a drain connected to the shunt 101, and a gate connected to the charging current detection circuit 102 and the signal output terminal of the MCU for receiving signals from the charging current detection circuit 102 and the MCU.
the invention can reasonably control the overlarge charging current in the lithium battery system, and prevent the lithium battery system from overcurrent protection or short-circuit protection and even the problem of fire and explosion; meanwhile, the lithium battery system is controlled only by detecting the charging current of the lithium battery system, and the charging voltage of the parallel battery pack or the charging equipment is not needed, so that the flexibility and the reliability of the whole parallel system are improved.
referring to fig. 2, the current limiting circuit 103 includes a second switch circuit 1031, an inductor L1, a MOS transistor Q1, a resistor R1, and a resistor R2.
The second switch circuit 1031, the resistor R2, the inductor L1, the MOS transistor Q1, and the resistor R1 are connected in series; one end of the second switching circuit 1031 is connected to the negative charging line 106 between the first switching circuit 104 and the shunt 101; one end of the resistor R1 is connected with the negative input end of the BMS 1; the resistor R2 is located between the second switching circuit 1031 and the inductor L1; the MOS transistor Q1 is located between the inductor L1 and the resistor R1.
When the lithium battery system normally operates, the second switch circuit 1031 is in an off state, and when the charging current is greater than a preset value, the MCU sends a signal S2 to the second switch circuit 1031 to turn on the second switch circuit 1031, thereby starting the entire current limiting circuit 103.
the second switch circuit 1031 is a master switch of the current limiting circuit 103, and when the second switch circuit 1031 is turned on, the system starts the current limiting circuit 103; when the second switching circuit is open, the system turns off the current limiting circuit 103.
In the current limiting circuit 103, the arrangement of the resistor R1 and the resistor R2 weakens the charging current; meanwhile, the inductor L1 also has a current limiting function on the flowing charging current, and serves as an energy storage element to convert a part of electric energy into magnetic energy for storage.
the second switch circuit 1031 may be an MOS transistor, a source of the MOS transistor is connected to the resistor R2, a drain of the MOS transistor is connected to the negative charging line 106 between the shunt 101 and the first switch circuit 104, and a gate of the MOS transistor is connected to a signal output terminal of the MCU, for receiving a signal sent by the MCU.
The current limiting circuit 103 further includes a resistor R3, a resistor R4, a capacitor C1, and a capacitor C2.
One end of the resistor R3 is connected with the resistor R4, and the other end is connected with the positive input end of the BMS 1; one end of the resistor R4 is connected to the resistor R3, and the other end is connected to an electric wire between the second switch circuit 1031 and the resistor R2; one end of the capacitor C1 is connected with the positive input end of the BMS1, and the other end is connected with a wire between the resistor R2 and the inductor L1; and two ends of the capacitor C2 are respectively connected with the positive and negative input ends of the BMS 1.
The capacitor C2 is the input capacitor of the whole current limiting circuit, the capacitor C1 is the output capacitor of the whole current limiting circuit, and the capacitors have the function of filtering the input/output of the whole current limiting circuit.
The current limiting circuit 103 also includes a control circuit 1032.
The control circuit 1032 is a core module of the current limiting circuit 103, and the control circuit 1032 adjusts PWM (Pulse width modulation) and outputs a duty ratio by detecting a voltage division of the current resistor R3 and the resistor R4, a current on the resistor R2, and a peak current on the resistor R1, thereby controlling on and off of the MOS transistor Q1 and limiting an output current of the entire current limiting circuit 103.
When the control circuit 1032 detects that the current of the resistor R2 is greater than the preset value, the PWM is adjusted to decrease the output duty ratio, so that the charging current is decreased to the preset value and remains stable.
When the control circuit 1032 detects that the current of the resistor R1 is larger than a preset value, the PWM is adjusted to decrease the output duty cycle, so that the whole circuit is stable.
When the control circuit 1032 detects that the output voltage is greater than the preset value, the PWM is adjusted to decrease the output duty ratio, so that the output voltage is decreased to approach the preset value and is kept stable.
The current limiting circuit 103 further includes a freewheeling diode D1.
the anode of the freewheeling diode D1 is connected to the line between the inductor L1 and the MOS transistor Q1, and the cathode is connected to the anode input terminal of the BMS 1.
when the MOS transistor Q1 is conducted, a part of energy is transmitted to the inductor L1, and meanwhile, a part of energy is used for charging the lithium battery pack; when the MOS transistor Q1 is turned off, the energy stored in the inductor L1 continues to charge the lithium battery through the freewheeling diode D1.
The freewheeling diode D1 is arranged to prevent the interruption of charging caused when the MOS transistor Q1 is turned off, and simultaneously, the energy stored in the inductor L1 is converted into electric energy to continue charging the battery, so that the loss of part of the energy is reduced, and meanwhile, the battery is protected to a certain extent.
BMS1 still contains fuse F1, and fuse F1 establishes ties on anodal charging wire 105, has played overload protection's effect to whole lithium battery charging circuit, has ensured the safe operation of whole lithium battery charging circuit.
The BMS1 further includes a fuse F2, one end of the fuse F2 is connected to the second switch circuit 1031, and the other end is connected to the negative charging wire 106 between the first switch circuit 104 and the shunt 101, so that the fuse F2 plays a role of overload protection for the current limiting circuit 103, thereby ensuring the safe operation of the current limiting circuit 103.
The charge current detection circuit 102 includes an amplifier 1021 and a comparison latch 1022.
The amplifier 1201 collects the charging current on the shunt 101, amplifies the current signal and outputs the amplified current signal to the comparison latch 1202, and the comparison latch 1202 compares the received current signal with a preset value.
The arrangement of the amplifier 1201 and the comparison latch 1022 realizes the judgment of the magnitude of the charging current by the charging current detection circuit, which is a precondition for the function of the whole current limiting circuit.
BMS1 also contains AFE (Analog Front End) that samples the temperature of the lithium battery pack and sends signals to the MCU.
2 temperature thresholds are arranged on the AFE, namely a threshold X and a threshold Y respectively; the threshold value X is smaller than the threshold value Y.
When the temperature of the lithium battery pack acquired by the AFE is greater than the threshold value X and less than the threshold value Y, a signal S5 is sent to the MCU, the MCU closes the signal S3, and simultaneously outputs a signal S2 to the current limiting circuit 103 to start the current limiting circuit 103.
When the temperature of the lithium battery pack collected by the AFE is greater than the threshold value Y, the AFE outputs a signal S6 to the MCU, the MCU turns off the signals S2 and S3, and the current limiting circuit 103 and the first switch circuit 104 are disconnected.
The AFE can prevent the problems of circuit faults, even fire, explosion and the like caused by overhigh temperature of the lithium battery system, and plays a role in protecting the lithium battery system.
The design of the whole lithium battery charging current limiting circuit shows that the charging and discharging of the battery pack are controlled by the negative pole, and the current limiting circuit is also controlled by the negative pole, so that the circuit is low in design cost and can be produced in large batch.
In summary, in the lithium battery charging current limiting system, when the charging current of the lithium battery system is too large, the system starts the current limiting circuit to limit the charging current, so that the charging current is reduced, the lithium battery system is prevented from being damaged by the too large current, and when the current is smaller than a preset value, the charging current loop can be switched to the main charging loop again, so that the current balance time of the battery module or the charging equipment connected in parallel is reduced. The device and the circuit adopted in the charging current-limiting system are common mature currents, the cost is very low, the current-limiting design is completely carried out according to the lithium battery system, the independent control is completely realized, the parallel connection form of the battery modules is not limited, and the installation operability and flexibility are greatly enhanced. In system maintenance, if a battery module needs to be replaced or added, the battery module can be connected in parallel at will without being limited to the communication form or the electric quantity of the battery module, and the system is high in maintainability and suitable for batch production.
The above description is only a preferred embodiment of the present invention, and not intended to limit the scope of the present invention, and all modifications of equivalent structures and equivalent processes, which are made by using the contents of the present specification and the accompanying drawings, or directly or indirectly applied to other related technical fields, are included in the scope of the present invention.
Claims (10)
1. A lithium battery charging current limiting system having a BMS (1) connected to a lithium battery pack, characterized in that: the BMS (1) comprises a positive charging wire (105), a negative charging wire (106), an MCU, a charging current detection circuit (102), a current limiting circuit (103), a first switch circuit (104) and a current divider (101);
A first end of the positive charging wire (105) is used for being connected with a positive electrode of the lithium battery pack, and a second end of the positive charging wire (105) is connected with a positive input end of the BMS (1);
The first end of the negative electrode charging wire (106) is used for being connected with the negative electrode of the lithium battery pack, and the second end of the negative electrode charging wire (106) is connected with the negative electrode input end of the BMS (1);
The shunt (101) and a first switching circuit (104) are arranged in series on the negative charging line (106); the current divider (101) is located between the first switching circuit (104) and a first end of the negative charging line (106);
the first end of the current limiting circuit (103) is connected with the negative input end of the BMS (1), and the second end of the current limiting circuit is connected with a negative charging wire (106) between the current divider (101) and the first switching circuit (104);
The charging current detection circuit (102) collects the charging current of the negative charging wire (106) through the current divider (101) and sends signals to the MCU and the first switch circuit (104);
The MCU receives the signals sent by the charging current detection circuit (102) and then sends corresponding signals to control the on and off of the first switch circuit (104) and the current limiting circuit (103);
When the lithium battery system normally operates, the MCU outputs a control signal S3 to control the first switch circuit (104) to be conducted; the current limiting circuit (103) is in an off state;
When the charging current detected by the charging current detection circuit (102) is greater than a preset value, the charging current detection circuit (102) outputs a signal S4 to the first switch circuit (104) to disconnect the first switch circuit (104), and outputs an overcurrent signal S1 to the MCU; after receiving the overcurrent signal S1, the MCU closes the signal S3, outputs a signal S2 to the current limiting circuit (103) and starts the current limiting circuit (103);
When the charging current detection circuit (102) detects that the charging current is smaller than the preset value, the charging current detection circuit (102) turns off the signal S4 and the over-current signal S1; the MCU retransmits the S3 signal to turn on the first switch circuit (104), and turns off the S2 signal to turn off the current limiting circuit (103).
2. the lithium battery charging current limiting system according to claim 1, wherein: the current limiting circuit (103) comprises a second switch circuit (1031), an inductor L1, a MOS tube Q1, a resistor R1 and a resistor R2;
the second switch circuit (1031), the resistor R2, the inductor L1, the MOS transistor Q1 and the resistor R1 are arranged in series; one end of the second switch circuit (1031) is connected to a negative charging line (106) between the first switch circuit (104) and the current divider (101); one end of the resistor R1 is connected with the negative input end of the BMS (1); the resistor R2 is located between the second switch circuit (1031) and an inductor L1; the MOS transistor Q1 is positioned between the inductor L1 and the resistor R1;
when the lithium battery system normally operates, the second switch circuit (1031) is in a disconnected state, and when the charging current is greater than a preset value, the MCU sends the signal S2 to the second switch circuit (1031) to turn on the second switch circuit (1031), so that the whole current limiting circuit (103) is started.
3. the lithium battery charging current limiting system according to claim 2, wherein: the current limiting circuit (103) further comprises a resistor R3, a resistor R4, a capacitor C1 and a capacitor C2;
one end of the resistor R3 is connected with the resistor R4, and the other end of the resistor R3 is connected with the positive input end of the BMS (1); one end of the resistor R4 is connected with the resistor R3, and the other end is connected with an electric wire between the second switch circuit (1031) and the resistor R2; one end of the capacitor C1 is connected with the positive input end of the BMS (1), and the other end is connected with a wire between the resistor R2 and the inductor L1; and two ends of the capacitor C2 are respectively connected with the positive and negative electrode input ends of the BMS (1).
4. The lithium battery charging current limiting system according to claim 3, wherein: the current limiting circuit (103) further comprises a control circuit (1032);
The control circuit (1032) adjusts PWM and outputs duty ratio by detecting the current voltage division of the resistor R3 and the resistor R4, the current on the resistor R2 and the peak current on the resistor R1, and then controls the on and off of the MOS transistor Q1 to limit the output current of the whole current limiting circuit (103).
5. The lithium battery charging current limiting system according to claim 4, wherein: the current limiting circuit (103) further comprises a freewheeling diode D1;
The anode of the freewheeling diode D1 is connected to the wire between the inductor L1 and the MOS transistor Q1, and the cathode of the freewheeling diode D1 is connected to the anode input end of the BMS (1);
when the MOS transistor Q1 is conducted, part of energy is transmitted to the inductor L1, and meanwhile, part of energy is used for charging the lithium battery pack;
When the MOS transistor Q1 is switched off, the energy stored in the inductor L1 continues to charge the lithium battery pack through the freewheeling diode D1.
6. The current limiting system for lithium battery charging according to any one of claims 1 to 5, wherein: the BMS (1) further comprises a fuse F1;
the fuse F1 is connected in series on the positive charging wire (105).
7. the lithium battery charging current limiting system of claim 6, wherein: the BMS (1) further comprises a fuse F2;
One end of the fuse F2 is connected with the second switch circuit (1031), and the other end is connected with a negative charging wire (106) between the first switch circuit (104) and the current divider (101).
8. The lithium battery charging current limiting system according to claim 7, wherein: the charging current detection circuit (102) comprises an amplifier (1021) and a comparison latch (1022);
The amplifier (1201) collects the charging current on the current divider (101), amplifies the current signal and outputs the amplified current signal to the comparison latch (1202);
The comparison latch (1202) compares the received current signal to a preset value.
9. The lithium battery charging current limiting system of claim 8, wherein: the BMS (1) further comprises an AFE;
and the AFE samples the temperature of the lithium battery pack and sends a signal to the MCU.
10. the lithium battery charging current limiting system of claim 9, wherein: 2 temperature thresholds are arranged on the AFE, namely a threshold X and a threshold Y respectively; the threshold value X is smaller than the threshold value Y;
When the temperature of the lithium battery pack collected by the AFE is greater than a threshold value X and less than a threshold value Y, sending a signal S5 to the MCU, turning off the signal S3 by the MCU, simultaneously outputting a signal S2 to the current limiting circuit (103), and starting the current limiting circuit (103);
when the temperature of the lithium battery pack collected by the AFE is greater than a threshold value Y, the AFE outputs a signal S6 to the MCU, the MCU turns off signals S2 and S3, and the current limiting circuit (103) and the first switch circuit (104) are disconnected.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910853388.2A CN110571883B (en) | 2019-09-10 | 2019-09-10 | Lithium battery charging current limiting system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910853388.2A CN110571883B (en) | 2019-09-10 | 2019-09-10 | Lithium battery charging current limiting system |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN110571883A true CN110571883A (en) | 2019-12-13 |
| CN110571883B CN110571883B (en) | 2023-05-09 |
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| CN113472035A (en) * | 2021-06-22 | 2021-10-01 | 深圳拓邦股份有限公司 | Lithium battery work control method and system and electric equipment |
| CN113872304A (en) * | 2021-10-27 | 2021-12-31 | 宁德时代科士达科技有限公司 | Parallel current limiting method of energy storage battery pack and energy storage battery pack |
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| CN110571883B (en) | 2023-05-09 |
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