CN115954987B - Secondary protection circuit for lithium battery charging - Google Patents
Secondary protection circuit for lithium battery charging Download PDFInfo
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- CN115954987B CN115954987B CN202310125270.4A CN202310125270A CN115954987B CN 115954987 B CN115954987 B CN 115954987B CN 202310125270 A CN202310125270 A CN 202310125270A CN 115954987 B CN115954987 B CN 115954987B
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- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 title claims abstract description 278
- 229910052744 lithium Inorganic materials 0.000 title claims abstract description 278
- 238000007599 discharging Methods 0.000 claims abstract description 45
- 238000001514 detection method Methods 0.000 claims abstract description 27
- 230000009471 action Effects 0.000 claims abstract description 17
- 208000028659 discharge Diseases 0.000 claims description 81
- 239000003990 capacitor Substances 0.000 claims description 26
- 238000005070 sampling Methods 0.000 claims description 8
- 238000010586 diagram Methods 0.000 description 3
- 230000000694 effects Effects 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 230000008859 change Effects 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- 238000004064 recycling Methods 0.000 description 1
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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 secondary protection circuit, which comprises a first lithium battery protection circuit, a second lithium battery protection circuit, a charging and discharging switch circuit and a three-terminal fuse, wherein the charging and discharging detection is carried out on a lithium battery pack through the first lithium battery protection circuit; the second lithium battery protection circuit is used for detecting the charge and discharge of the lithium battery pack; the charge-discharge switch circuit performs switch control on a charge-discharge loop of the lithium battery pack under the action of the first lithium battery protection circuit; the three-terminal fuse is arranged on the charge-discharge loop of the lithium battery pack to carry out overcurrent protection on the charge-discharge loop of the lithium battery pack, and the three-terminal fuse also carries out closing control on the charge-discharge loop of the lithium battery pack under the action of the second lithium battery protection circuit. In this way, even if the lithium battery pack is charged unattended, the risk of fire due to excessive current during charging can be greatly reduced, resulting in double protection.
Description
Technical Field
The invention relates to the technical field of lithium battery protection circuits, in particular to a secondary lithium battery charging protection circuit.
Background
In recent years, secondary batteries such as lithium (Li) ion batteries have been widely used. After the lithium battery pack is discharged for one time, the lithium battery pack can be charged continuously in a charging mode, so that repeated recycling is realized. Since the current charging is usually performed by voltage conversion by the commercial ac, the lithium battery pack is charged. Under the unattended condition, the lithium battery pack is connected with the commercial power alternating current through the charger for a long time. Various fault conditions such as short circuits may be caused for various unknown reasons, thereby increasing the risk of ignition of the lithium battery.
Disclosure of Invention
The present invention aims to solve at least one of the technical problems in the related art to some extent. Therefore, an object of the present invention is to provide a secondary protection circuit for lithium battery charging.
In order to achieve the above object, an embodiment of the present invention provides a secondary protection circuit for charging a lithium battery, including:
the first lithium battery protection circuit is connected with the lithium battery pack to perform charge and discharge detection on the lithium battery pack;
the second lithium battery protection circuit is connected with the lithium battery pack to perform charge and discharge detection on the lithium battery pack;
the charging and discharging switch circuit is connected with the first lithium battery protection circuit to perform switching control on a charging and discharging loop of the lithium battery pack under the action of the first lithium battery protection circuit;
the three-terminal fuse is arranged on the charging and discharging loop of the lithium battery pack so as to carry out overcurrent protection on the charging and discharging loop of the lithium battery pack, and the three-terminal fuse is also connected with the second lithium battery protection circuit so as to carry out closing control on the charging and discharging loop of the lithium battery pack under the action of the second lithium battery protection circuit.
Further, according to an embodiment of the present invention, the first lithium battery protection circuit includes:
the lithium battery protection chip is respectively connected with each lithium battery of the lithium battery pack to obtain charging and discharging information of each lithium battery; the controlled end of the charge-discharge switch circuit is connected with the charge-discharge control end of the first lithium battery protection chip so as to control the charge-discharge of the lithium battery pack under the action of the first lithium battery protection chip.
Further, according to an embodiment of the present invention, the charge-discharge switching circuit includes:
the source electrode of the discharge MOS tube QD1 is connected with the negative end of the lithium battery pack, and the grid electrode of the discharge MOS tube QD1 is connected with the charging signal control end of the first lithium battery protection chip;
the charging MOS tube QC1, the drain electrode of charging MOS tube QC1 with the drain electrode of discharging MOS tube QD1 is connected, the negative end of charging MOS tube QC 1's source charge-discharge interface is connected, charging MOS tube QC 1's grid with the discharge signal control end of first lithium cell protection chip is connected.
Further, according to an embodiment of the present invention, a plurality of the discharge MOS transistors QD1 are provided, respectively, and the plurality of the discharge MOS transistors QD1 are connected in parallel to each other;
the charging MOS tube QC1 is respectively provided with a plurality of charging MOS tubes QC1 which are connected in parallel.
Further, according to an embodiment of the present invention, the lithium battery charging secondary protection circuit further includes:
the sampling resistor RS1 is arranged on a charge-discharge loop of the lithium battery pack, and the sampling resistor RS1 is connected with a circuit detection end of the first lithium battery protection circuit so as to carry out overcurrent protection through the first lithium battery protection circuit.
Further, according to an embodiment of the present invention, the second lithium battery protection circuit includes:
the second lithium battery protection chip is respectively connected with each lithium battery of the lithium battery pack to obtain charging and discharging information of each lithium battery;
the first MOS pipe Q3, the grid of first MOS pipe Q3 pass through first resistance R17 with the charge protection control end of second lithium cell protection chip is connected, the source of first MOS pipe Q3 is connected with reference ground, the source of first MOS pipe Q3 still pass through second resistance R18 with the grid of first MOS pipe Q3 is connected, the three-terminal fuse of drain electrode of first MOS pipe Q3 is connected, in order to right the three-terminal fuse fuses carries out the fuse control.
Further, according to an embodiment of the present invention, the three-terminal fuse includes:
and one end of the fuse is connected with the positive end of the lithium battery pack, the other end of the fuse is connected with the positive end of the charge-discharge interface, and the middle part or one end of the fuse is also connected with the drain electrode of the first MOS tube Q3.
Further, according to an embodiment of the present invention, the lithium battery charging secondary protection circuit further includes: the temperature detection circuit is used for detecting the temperature of the charge-discharge loop, and comprises:
one end of the third resistor R5 is connected with the temperature detection end of the first lithium battery protection chip;
and one end of the thermistor T2 is connected with the other end of the third resistor R5, and the other end of the thermistor T2 is connected with the reference ground.
Further, according to an embodiment of the present invention, the secondary lithium battery charging protection circuit further includes a secondary discharging circuit, and the secondary discharging circuit is connected to the second lithium battery protection circuit, so as to control the discharging of the lithium battery pack under the control of the second lithium battery protection circuit after the three-terminal fuse is melted;
the secondary discharge circuit includes:
a first diode D3, wherein the anode of the first diode D3 is connected with the positive end of the lithium battery pack;
the drain electrode of the second MOS tube Q6 is connected with the cathode of the first diode D3, and the source electrode of the second MOS tube Q6 is connected with the positive end of the charge-discharge interface;
the drain electrode of the third MOS tube Q7 is connected with the grid electrode of the second MOS tube Q6 through a fourth resistor R32, the source machine of the third MOS tube Q7 is connected with the reference ground, and the grid electrode of the third MOS tube Q7 is connected with a control end of the second lithium battery protection chip;
and the cut-off level voltage circuit is respectively connected with the control end of the second lithium battery protection chip and the grid electrode of the second MOS tube Q6 so as to provide cut-off control power supply voltage for the second MOS tube Q6 under the control of the second lithium battery protection chip.
Further, according to an embodiment of the present invention, the off-level voltage circuit includes:
the collector of the first triode Q4 is connected with the positive end of the lithium battery pack, the base of the first triode Q4 is connected with the control end of the second lithium battery protection chip, and the base of the first triode Q4 is also connected with the positive end of the lithium battery pack through a fifth resistor R30;
the emitter of the second triode Q5 is connected with the emitter of the first triode Q4, the collector of the second triode Q5 is connected with the reference ground, and the base of the second triode Q5 is connected with the base of the first triode Q4;
a second diode D4, wherein an anode of the second diode D4 is connected with an anode of a first lithium battery of the lithium battery pack;
a first capacitor C17, wherein one end of the first capacitor C17 is connected with the cathode of the second diode D4, and the other end of the first capacitor C17 is connected with the emitter of the second triode Q5;
a third diode D5, an anode of the third diode D5 is connected to the one end of the first capacitor C17;
and one end of the second capacitor C18 is connected with the cathode of the third diode D5, the other end of the second capacitor C18 is connected with the reference ground, and one end of the second capacitor C18 is connected with the grid electrode of the second MOS tube Q6.
The lithium battery charging secondary protection circuit provided by the embodiment of the invention is connected with the lithium battery pack through the first lithium battery protection circuit so as to perform charging and discharging detection on the lithium battery pack; the second lithium battery protection circuit is connected with the lithium battery pack to perform charge and discharge detection on the lithium battery pack; the charge-discharge switch circuit is connected with the first lithium battery protection circuit to perform switch control on a charge-discharge loop of the lithium battery pack under the action of the first lithium battery protection circuit; the three-terminal fuse is arranged on the charge-discharge loop of the lithium battery pack so as to carry out overcurrent protection on the charge-discharge loop of the lithium battery pack, and the three-terminal fuse is also connected with the second lithium battery protection circuit so as to carry out closing control on the charge-discharge loop of the lithium battery pack under the action of the second lithium battery protection circuit. In this way, even if the lithium battery pack is charged unattended, the risk of fire due to excessive current during charging can be greatly reduced, resulting in double protection.
Drawings
Fig. 1 is a block diagram of a secondary protection circuit for lithium battery charging according to an embodiment of the present invention;
fig. 2 is a schematic diagram of a first lithium battery protection circuit and a temperature detection circuit according to an embodiment of the present invention;
fig. 3 is a schematic diagram of a second lithium battery protection circuit according to an embodiment of the present invention.
The achievement of the objects, functional features and advantages of the present invention will be further described with reference to the accompanying drawings, in conjunction with the embodiments.
Detailed Description
In order to enable those skilled in the art to better understand the present invention, the following description will make clear and complete descriptions of the technical solutions according to the embodiments of the present invention with reference to the accompanying drawings. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.
Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the invention. The appearances of such phrases in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. Those of skill in the art will explicitly and implicitly appreciate that the embodiments described herein may be combined with other embodiments.
Referring to fig. 1, an embodiment of the present invention provides a secondary protection circuit for charging a lithium battery, including: the lithium battery pack charging and discharging device comprises a first lithium battery protection circuit, a second lithium battery protection circuit, a charging and discharging switch circuit and a three-terminal fuse, wherein the first lithium battery protection circuit is connected with the lithium battery pack to conduct charging and discharging detection on the lithium battery pack; specifically, as shown in fig. 2, the first lithium battery protection circuit includes: the lithium battery protection device comprises a first lithium battery protection chip U1, wherein the first lithium battery protection chip U1 is respectively connected with each lithium battery of the lithium battery pack to acquire charge and discharge information of each lithium battery; the voltage detection terminals VC 1-VC 5 of the first lithium battery protection chip U1 are respectively connected with each lithium battery in the lithium battery pack so as to detect the voltage of charging and discharging each lithium battery and realize overcharge and overdischarge detection and protection control of the lithium battery pack.
The second lithium battery protection circuit is connected with the lithium battery pack to perform charge and discharge detection on the lithium battery pack; as shown in fig. 3, the second lithium battery protection circuit includes: the second lithium battery protection chip U2 and the first MOS tube Q3 are respectively connected with each lithium battery of the lithium battery pack to obtain charging and discharging information of each lithium battery; the voltage detection terminals VC 1-VC 5 of the second lithium battery protection chip U2 are respectively connected with each lithium battery in the lithium battery pack so as to detect the voltage of charging and discharging each lithium battery and realize overcharge and overdischarge detection and protection control of the lithium battery pack. The grid of first MOS pipe Q3 is connected with the charge protection control end CO of second lithium cell protection chip U2 through first resistance R17, the source of first MOS pipe Q3 is connected with ground, the source of first MOS pipe Q3 still through second resistance R18 with the grid of first MOS pipe Q3 is connected, the three-terminal fuse of drain electrode of first MOS pipe Q3 is connected, in order to right the three-terminal fuse fuses carries out the fuse control. In this way, the first MOS transistor Q3 may be turned on or turned off under the effect of the charging control signal of the second lithium battery protection chip U2.
The controlled end of the charge-discharge switch circuit is connected with the first lithium battery protection circuit so as to carry out switch control on the charge-discharge loop of the lithium battery pack under the action of the first lithium battery protection circuit; specifically, the charge-discharge switch circuit is connected with the charge-discharge control end of the first lithium battery protection chip U1, so as to control the charge-discharge of the lithium battery pack under the action of the first lithium battery protection chip. That is, the first lithium battery protection chip U1 on the first lithium battery protection circuit may perform charge and discharge control on the charge and discharge switch circuit, so as to implement the first re-protection of charge and discharge of the lithium battery pack. The second protection is realized by the second lithium battery protection chip U2 of the second lithium battery protection circuit. Specifically, the three-terminal fuse is arranged on the charging and discharging loop of the lithium battery pack so as to perform overcurrent protection on the charging and discharging loop of the lithium battery pack, and the three-terminal fuse is also connected with the second lithium battery protection circuit so as to perform closing control on the charging and discharging loop of the lithium battery pack under the action of the second lithium battery protection circuit. As shown in fig. 3, both ends of the three-terminal fuse are disposed on a charge-discharge loop of the lithium battery pack, the three-terminal fuse including: and one end of the fuse is connected with the positive end of the lithium battery pack, the other end of the fuse is connected with the positive end of the charge-discharge interface, and the middle part or one end of the fuse is also connected with the drain electrode of the first MOS tube Q3. When the charge and discharge loop is over-current, the three-terminal fuse can be directly fused to realize over-current protection. In addition, when the second lithium battery protection chip U2 detects that the lithium battery pack is overcharged, the first MOS tube Q3 can be controlled to be conducted, and large current can be generated when the first MOS tube Q3 is conducted, so that the three-terminal fuse can be fused, and the second heavy lithium battery pack overcharge protection control is realized.
The lithium battery charging secondary protection circuit provided by the embodiment of the invention is connected with the lithium battery pack through the first lithium battery protection circuit so as to perform charging and discharging detection on the lithium battery pack; the second lithium battery protection circuit is connected with the lithium battery pack to perform charge and discharge detection on the lithium battery pack; the charge-discharge switch circuit is connected with the first lithium battery protection circuit to perform switch control on a charge-discharge loop of the lithium battery pack under the action of the first lithium battery protection circuit; the three-terminal fuse is arranged on the charge-discharge loop of the lithium battery pack so as to carry out overcurrent protection on the charge-discharge loop of the lithium battery pack, and the three-terminal fuse is also connected with the second lithium battery protection circuit so as to carry out closing control on the charge-discharge loop of the lithium battery pack under the action of the second lithium battery protection circuit. In this way, even if the lithium battery pack is charged unattended, the risk of fire due to excessive current during charging can be greatly reduced, resulting in double protection.
Referring to fig. 2, the charge-discharge switching circuit includes: the lithium battery pack comprises a discharging MOS tube QD1 and a charging MOS tube QC1, wherein a source electrode of the discharging MOS tube QD1 is connected with a negative end of the lithium battery pack, and a grid electrode of the discharging MOS tube QD1 is connected with a charging signal control end of a first lithium battery protection chip U1; when the first lithium battery protection chip U1 detects that the lithium battery pack is overdischarged, a low-level overdischarge protection signal is output to the gate of the discharge MOS tube QD1 through the DSG end, and the discharge MOS tube QD1 is turned off by the level signal, so that the discharge loop is turned off, and the lithium battery pack stops discharging.
The drain electrode of the charging MOS tube QC1 is connected with the drain electrode of the discharging MOS tube QD1, the source electrode of the charging MOS tube QC1 is connected with the negative end of the charging and discharging interface, and the grid electrode of the charging MOS tube QC1 is connected with the discharging signal control end of the first lithium battery protection chip. When the first lithium battery protection chip U1 detects that the lithium battery pack is overcharged, a low-level overcharge protection signal is output to the grid electrode of the charging MOS tube QC1 through the CHG end, the discharging MOS tube QC1 can be cut off by the level signal, so that a charging loop is cut off, and an external power supply stops charging the lithium battery pack.
Referring to fig. 2, a plurality of discharge MOS transistors QD1 are provided, and the plurality of discharge MOS transistors QD1 are connected in parallel; the MOS tube M1 is provided with a plurality of MOS tubes (QD 1, QD2 and QD 3) which are connected in parallel. This increases the amount of current in the discharge loop. The grids of the MOS tubes (QD 1, QD2 and QD 3) are respectively connected with the discharge control signal end of the first lithium battery protection chip U1 so as to be conducted or cut off under the action of the discharge control signal, so that the discharge of the lithium battery pack is controlled.
The charging MOS tube QC1 is respectively provided with a plurality of charging MOS tubes QC1 which are connected in parallel. The MOS tube QC1 is provided with a plurality of MOS tubes (QC 1, QC2 and QC 3) which are connected in parallel. This increases the amount of current in the charging loop. The grid electrodes of the MOS tubes (QC 1, QC2 and QC 3) are respectively connected with the charging control signal end of the first lithium battery protection chip U1 so as to be conducted or cut off under the action of the charging control signal to control the charging of the lithium battery pack.
Referring to fig. 2, the secondary protection circuit for lithium battery charging further includes: the sampling resistor RS1 is arranged on a charge-discharge loop of the lithium battery pack, and the sampling resistor RS1 is connected with a circuit detection end of the first lithium battery protection circuit so as to carry out overcurrent protection through the first lithium battery protection circuit. The sampling resistor RS1 is arranged on a charge-discharge loop of the lithium battery pack to detect charge-discharge current of the lithium battery pack, and when overcurrent is detected, the first lithium battery protection chip U1 can output a control signal to the discharge MOS tube (QD 1, QD2 and QD 3) or the charge MOS tube (QC 1, QC2 and QC 3) so that the discharge MOS tube (QD 1, QD2 and QD 3) or the charge MOS tube (QC 1, QC2 and QC 3) is cut off, and overcurrent protection is realized.
Referring to fig. 1 and 2, the secondary protection circuit for lithium battery charging further includes: the temperature detection circuit is used for detecting the temperature of the charge-discharge loop, and comprises: the lithium battery protection chip comprises a third resistor R5 and a thermistor T2, wherein one end of the third resistor R5 is connected with a temperature detection end of the first lithium battery protection chip U1; one end of the thermistor T2 is connected with the other end of the third resistor R5, and the other end of the thermistor T2 is connected with the reference ground. Since the resistance value of the thermistor T2 is changed due to the temperature change, the voltage value of the signal detection terminal T2 of the temperature detection terminal of the first lithium battery protection chip U1 is also different. The first lithium battery protection chip U1 can acquire corresponding temperature information through the detected voltage value T.
Referring to fig. 3, the secondary lithium battery charging protection circuit further includes a secondary discharging circuit, and the secondary discharging circuit is connected with the second lithium battery protection circuit, so as to control the discharging of the lithium battery pack under the control of the second lithium battery protection circuit after the three-terminal fuse is melted; in the charging process, phenomena such as overcurrent and overvoltage may occur, and at the moment, the three-terminal fuse is fused, and since the lithium battery may be fully charged at the moment, the power supply of the lithium battery pack can be fully discharged through the secondary discharging circuit so as to fully utilize the power supply of the lithium battery pack and better protect the lithium battery pack.
The secondary discharge circuit includes: the lithium battery pack comprises a first diode D3, a second MOS tube Q6, a third MOS tube Q7 and a cut-off level voltage circuit, wherein the anode of the first diode D3 is connected with the positive end of the lithium battery pack; the drain electrode of the second MOS tube Q6 is connected with the cathode of the first diode D3, and the source electrode of the second MOS tube Q6 is connected with the positive end of the charge-discharge interface; the drain electrode of the third MOS tube Q7 is connected with the grid electrode of the second MOS tube Q6 through a fourth resistor R32, the source machine of the third MOS tube Q7 is connected with the reference ground, and the grid electrode of the third MOS tube Q7 is connected with a control end of the second lithium battery protection chip; the cut-off level voltage circuit is respectively connected with the control end of the second lithium battery protection chip and the grid electrode of the second MOS tube Q6, so as to provide cut-off control power supply voltage for the second MOS tube Q6 under the control of the second lithium battery protection chip. As shown in fig. 3, the third MOS transistor Q7 and the off-level voltage circuit may perform on-off control on the second MOS transistor Q6 under the control of the second lithium battery protection circuit, so as to implement secondary discharge control on the lithium battery pack. Specifically, when the second lithium battery protection chip U2 outputs a high-level signal through the CON control end, the third MOS transistor Q7 may be turned on, the gate of the second MOS transistor Q6 is pulled down to a low level, the second MOS transistor Q6 is turned on, and the power supply of the lithium battery pack discharges to the outside through the first diode D3. When the second lithium battery protection chip U2 outputs a low-level signal through the CON control end, the third MOS tube Q7 can be cut off, the grid electrode of the second MOS tube Q6 can be cut off under the high-level effect output by the cut-off level voltage circuit, and the secondary discharge loop is closed.
Referring to fig. 3, the off-level voltage circuit includes: the lithium battery pack comprises a first triode Q4, a second triode Q5, a second diode D4, a first capacitor C17, a third diode D5 and a second capacitor C18, wherein a collector electrode of the first triode Q4 is connected with the positive end of the lithium battery pack, a base electrode of the first triode Q4 is connected with the other control end of the second lithium battery protection chip, and a base electrode of the first triode Q4 is also connected with the positive end of the lithium battery pack through a fifth resistor R30; an emitter of the second triode Q5 is connected with an emitter of the first triode Q4, a collector of the second triode Q5 is connected with a reference ground, and a base of the second triode Q5 is connected with a base of the first triode Q4; the anode of the second diode D4 is connected with the anode of the first lithium battery of the lithium battery pack; one end of the first capacitor C17 is connected with the cathode of the second diode D4, and the other end of the first capacitor C17 is connected with the emitter of the second triode Q5; the anode of the third diode D5 is connected to the one end of the first capacitor C17; one end of the second capacitor C18 is connected to the cathode of the third diode D5, the other end of the second capacitor C18 is connected to the ground, and the one end of the second capacitor C18 is connected to the gate of the second MOS transistor Q6.
Specifically, as shown in fig. 3, when the second lithium battery protection circuit outputs a low-level signal, the second transistor Q5 may be turned on, at this time, the power supply B1 of the first lithium battery charges the first capacitor C17 through the second diode D4, when the second lithium battery protection circuit outputs a low-level or high-resistance signal, the second transistor Q5 is turned off, the first transistor Q4 is turned on, the voltage b+ of the lithium battery pack may be loaded on the negative terminal of the first capacitor C17, so that the voltage of the first capacitor C17 is the sum of the voltages of b+ and B1, and the voltage of the second capacitor C18 may be increased to the sum of the voltages of b+ and B1 through the third diode D5, and the voltage may act on the gate of the second MOS transistor Q6 through the resistor R31, so that the turn-off control of the second MOS transistor Q6 may be achieved. In this way, under the control of the second lithium battery protection chip U2, the on or off control of the second MOS transistor Q6 can be realized. Thereby realizing the second discharge control of the lithium battery pack.
Although the present invention has been described in detail with reference to the foregoing embodiments, it will be apparent to those skilled in the art that the present invention may be modified or equivalents substituted for some of the features thereof. All equivalent structures made by the content of the specification and the drawings of the invention are directly or indirectly applied to other related technical fields, and are also within the scope of the invention.
In the description of the present specification, a description referring to terms "one embodiment," "some embodiments," "examples," "specific examples," or "some examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiments or examples. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.
Although embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and not to be construed as limiting the invention, and that variations, modifications, alternatives, and variations may be made in the above embodiments by those skilled in the art without departing from the spirit and principles of the invention.
Claims (7)
1. A secondary protection circuit for lithium battery charging, comprising:
the first lithium battery protection circuit is connected with the lithium battery pack to perform charge and discharge detection on the lithium battery pack;
the second lithium battery protection circuit is connected with the lithium battery pack to perform charge and discharge detection on the lithium battery pack;
the charging and discharging switch circuit is connected with the first lithium battery protection circuit to perform switching control on a charging and discharging loop of the lithium battery pack under the action of the first lithium battery protection circuit;
the three-terminal fuse is arranged on the charging and discharging loop of the lithium battery pack to carry out overcurrent protection on the charging and discharging loop of the lithium battery pack, and is also connected with the second lithium battery protection circuit to carry out closing control on the charging and discharging loop of the lithium battery pack under the action of the second lithium battery protection circuit;
wherein, the second lithium battery protection circuit includes: the second lithium battery protection chip is respectively connected with each lithium battery of the lithium battery pack to obtain charging and discharging information of each lithium battery; the grid electrode of the first MOS tube (Q3) is connected with the charging protection control end of the second lithium battery protection chip through a first resistor (R17), the source electrode of the first MOS tube (Q3) is connected with the reference ground, the source electrode of the first MOS tube (Q3) is also connected with the grid electrode of the first MOS tube (Q3) through a second resistor (R18), and the drain electrode of the first MOS tube (Q3) is connected with a three-terminal fuse so as to fuse the three-terminal fuse;
wherein the three-terminal fuse includes: one end of the fuse is connected with the positive end of the lithium battery pack, the other end of the fuse is connected with the positive end of the charge-discharge interface, and the middle part or the one end of the fuse is also connected with the drain electrode of the first MOS tube (Q3);
the secondary discharging circuit is connected with the second lithium battery protection circuit so as to control the lithium battery pack to be discharged under the control of the second lithium battery protection circuit after the three-terminal safety is melted; wherein the secondary discharge circuit includes:
a first diode (D3), wherein the anode of the first diode (D3) is connected with the positive end of the lithium battery pack;
the drain electrode of the second MOS tube (Q6) is connected with the cathode of the first diode (D3), and the source electrode of the second MOS tube (Q6) is connected with the positive end of the charge-discharge interface;
the drain electrode of the third MOS tube (Q7) is connected with the grid electrode of the second MOS tube (Q6) through a fourth resistor R32, the source machine of the third MOS tube (Q7) is connected with the reference ground, and the grid electrode of the third MOS tube (Q7) is connected with a control end of the second lithium battery protection chip;
and the cut-off level voltage circuit is respectively connected with the control end of the second lithium battery protection chip and the grid electrode of the second MOS tube (Q6) so as to provide cut-off control power supply voltage for the second MOS tube (Q6) under the control of the second lithium battery protection chip.
2. The lithium battery charging secondary protection circuit of claim 1, wherein the first lithium battery protection circuit comprises:
the lithium battery protection chip is respectively connected with each lithium battery of the lithium battery pack to obtain charging and discharging information of each lithium battery; the controlled end of the charge-discharge switch circuit is connected with the charge-discharge control end of the first lithium battery protection chip so as to control the charge-discharge of the lithium battery pack under the action of the first lithium battery protection chip.
3. The lithium battery charging secondary protection circuit of claim 2, wherein the charge-discharge switching circuit comprises:
the source electrode of the discharge MOS tube (QD 1) is connected with the negative end of the lithium battery pack, and the grid electrode of the discharge MOS tube (QD 1) is connected with the charging signal control end of the first lithium battery protection chip;
the charging MOS tube (QC 1), the drain electrode of charging MOS tube (QC 1) with the drain electrode of discharging MOS tube (QD 1) is connected, the negative terminal of the source electrode charge-discharge interface of charging MOS tube (QC 1) is connected, the grid of charging MOS tube (QC 1) with the discharge signal control end of first lithium cell protection chip is connected.
4. A lithium battery charging secondary protection circuit according to claim 3, characterized in that a plurality of discharge MOS tubes (QD 1) are provided, respectively, and a plurality of the discharge MOS tubes (QD 1) are connected in parallel with each other;
the charging MOS tubes (QC 1) are respectively provided with a plurality of charging MOS tubes (QC 1) which are connected in parallel.
5. The lithium battery charging secondary protection circuit of claim 1, further comprising:
the sampling resistor (RS 1), the sampling resistor (RS 1) sets up on the charge-discharge circuit of lithium cell group, sampling resistor (RS 1) with the circuit detection end of first lithium cell protection circuit is connected, in order to pass through first lithium cell protection circuit carries out overcurrent protection.
6. The lithium battery charging secondary protection circuit of claim 2, further comprising: the temperature detection circuit is used for detecting the temperature of the charge-discharge loop, and comprises:
one end of the third resistor (R5) is connected with the temperature detection end of the first lithium battery protection chip;
and one end of the thermistor (T2) is connected with the other end of the third resistor (R5), and the other end of the thermistor (T2) is connected with the reference ground.
7. The lithium battery charging secondary protection circuit of claim 1, wherein the cut-off level voltage circuit comprises:
the collector of the first triode (Q4) is connected with the positive end of the lithium battery pack, the base of the first triode (Q4) is connected with the control end of the second lithium battery protection chip, and the base of the first triode (Q4) is also connected with the positive end of the lithium battery pack through a fifth resistor R30;
the emitter of the second triode (Q5) is connected with the emitter of the first triode (Q4), the collector of the second triode (Q5) is connected with the reference ground, and the base of the second triode (Q5) is connected with the base of the first triode (Q4);
a second diode (D4), an anode of the second diode (D4) being connected to an anode of a first lithium battery of the lithium battery pack;
a first capacitor (C17), wherein one end of the first capacitor (C17) is connected with the cathode of the second diode (D4), and the other end of the first capacitor (C17) is connected with the emitter of the second triode (Q5);
-a third diode (D5), the anode of said third diode (D5) being connected to said one end of said first capacitor (C17);
and one end of the second capacitor (C18) is connected with the cathode of the third diode (D5), the other end of the second capacitor (C18) is connected with the reference ground, and one end of the second capacitor (C18) is connected with the grid electrode of the second MOS tube (Q6).
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| Application Number | Priority Date | Filing Date | Title |
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| CN202310125270.4A CN115954987B (en) | 2023-02-03 | 2023-02-03 | Secondary protection circuit for lithium battery charging |
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| CN202310125270.4A CN115954987B (en) | 2023-02-03 | 2023-02-03 | Secondary protection circuit for lithium battery charging |
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Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN201601478U (en) * | 2009-12-31 | 2010-10-06 | 深圳市力通威电子科技有限公司 | Protective circuit of soft-packaged lithium batteries |
| CN205070405U (en) * | 2015-09-25 | 2016-03-02 | 新源国宏科技（北京）有限公司 | Simulate non - balanced BMS protection shield with secondary protect function |
| CN105490327A (en) * | 2015-11-10 | 2016-04-13 | 浙江超威创元实业有限公司 | Three-layer protection system for lithium battery pack and control method of three-layer protection system |
| CN216959356U (en) * | 2021-12-13 | 2022-07-12 | 青岛航天汇能动力系统有限公司 | Protection circuit for charging and discharging of lithium battery and lithium battery management system |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6501248B2 (en) * | 2000-09-28 | 2002-12-31 | Ricoh Company, Ltd. | Charge/discharge protection apparatus having a charge-state overcurrent detector, and battery pack including the same |
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2023
- 2023-02-03 CN CN202310125270.4A patent/CN115954987B/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN201601478U (en) * | 2009-12-31 | 2010-10-06 | 深圳市力通威电子科技有限公司 | Protective circuit of soft-packaged lithium batteries |
| CN205070405U (en) * | 2015-09-25 | 2016-03-02 | 新源国宏科技（北京）有限公司 | Simulate non - balanced BMS protection shield with secondary protect function |
| CN105490327A (en) * | 2015-11-10 | 2016-04-13 | 浙江超威创元实业有限公司 | Three-layer protection system for lithium battery pack and control method of three-layer protection system |
| CN216959356U (en) * | 2021-12-13 | 2022-07-12 | 青岛航天汇能动力系统有限公司 | Protection circuit for charging and discharging of lithium battery and lithium battery management system |
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| CN115954987A (en) | 2023-04-11 |
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