CN210514567U - Detection circuit for internal resistance of lithium battery - Google Patents
Detection circuit for internal resistance of lithium battery Download PDFInfo
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- CN210514567U CN210514567U CN201920855608.0U CN201920855608U CN210514567U CN 210514567 U CN210514567 U CN 210514567U CN 201920855608 U CN201920855608 U CN 201920855608U CN 210514567 U CN210514567 U CN 210514567U
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Abstract
The utility model discloses a detection circuitry of lithium cell internal resistance. The utility model discloses a detection circuitry of lithium cell internal resistance, adopt the signal acquisition circuit to carry out signal acquisition with the mode output of constant current discharge through the control lithium cell, the voltage signal who gathers is very stable, the precision of detection has been ensured, and carry out the difference amplification to the difference amplifier circuit with the signal transmission after gathering, the influence of common mode signal has been eliminated, avoided because the secondary sampling of master control circuit and the stack of producing the error, the precision of detection has been improved, and can not cause any damage to the lithium cell, can repeat many times and detect the lithium cell internal resistance.
Description
Technical Field
The utility model relates to a lithium cell technical field especially relates to a detection circuitry of lithium cell internal resistance.
Background
The internal resistance of the lithium battery is an important index for evaluating the performance of the lithium battery, and can reflect the current state of charge (SOC) and the state of health (SOH) of the battery. The detection method for researching the internal resistance of the lithium battery has important significance for monitoring the health state and the use condition of the lithium battery. The measurement of the internal resistance of the lithium battery is a difficult point, on one hand, the internal resistance of the lithium battery is very small (generally in the milliohm level), the lithium battery is an active device, the internal structure is complex, and the lithium battery is different from a common resistance component and cannot be directly measured; on the other hand, the internal resistance of the lithium battery is not constant, and various factors such as the charge state, the cycle frequency, the external temperature and the like of the lithium battery can influence the internal resistance of the lithium battery.
The existing lithium battery internal resistance measuring method mainly comprises an open-circuit voltage method, a direct-current discharge method and an alternating-current injection method, wherein the open-circuit voltage method is to establish a relation curve of an open-circuit voltage (OCV) and an internal resistance of a battery by measuring the OCV and the internal resistance in advance, and the internal resistance of the battery can be obtained by looking up a table as long as the OCV of the battery is known; the direct current discharge method is used for detecting the lithium ion battery with small capacity by forcibly introducing instant constant current into the battery, the loss of the lithium ion battery with small capacity is large, the larger the current passing through the battery is, the more serious the polarization phenomenon of the battery is, and the larger the detection error is; the alternating current injection method is characterized in that an alternating current small signal with the frequency of 1kHz and the amplitude of 50mA is injected into two ends of a battery to be measured, and then voltage responses of the two ends of the battery are measured, so that the internal resistance of the lithium battery is measured, and the measurement accuracy is low, a measurement circuit is complex and is easily interfered. Therefore, the existing lithium battery internal resistance measurement methods cannot meet the requirement of high precision.
SUMMERY OF THE UTILITY MODEL
The utility model provides a detection circuitry of lithium cell internal resistance to solve the technical problem that the detection precision is low that current lithium cell internal resistance measurement method exists.
According to one aspect of the present invention, there is provided a circuit for detecting internal resistance of a lithium battery, comprising a battery access port for inserting the lithium battery, a signal acquisition circuit for acquiring signals by controlling constant current discharge of the lithium battery, a differential amplification circuit for differentially amplifying the signals acquired by the signal acquisition circuit, a main control circuit for sampling the signals amplified by the differential amplification circuit and for providing a reference voltage to the signal acquisition circuit,
the signal acquisition circuit is respectively connected with the battery access port and the differential amplification circuit, the differential amplification circuit is connected with the main control circuit, and the main control circuit is also connected with the signal acquisition circuit.
The first voltage stabilizing circuit and the second voltage stabilizing circuit are both connected with the battery access port, the first voltage stabilizing circuit is further connected with the signal acquisition circuit and the differential amplification circuit respectively, and the second voltage stabilizing circuit is connected with the main control circuit.
Further, the signal acquisition circuit comprises an analog switch S1, a dial switch SW1, a field effect transistor Q1, a capacitor C1, a resistor R1, a resistor R2, a resistor R3, a resistor R4, a resistor R5 and a double operational amplifier U1,
the No. 1 pin of the analog switch S1 is connected with a master control circuit, the No. 5 pin of the analog switch S1 is connected with a battery access port, the No. 4 pin of the analog switch S1 is connected with the first end of a capacitor C1, the second end of a capacitor C1 is grounded, the first end of a toggle switch SW1 is connected with the No. 5 pin of the analog switch S1, the second end of the toggle switch SW1 is connected with the source electrode of a field-effect tube Q1, the drain electrode of the field-effect tube Q1 is respectively connected with the first end of a resistor R1 and the first end of a resistor R2, the control electrode of the field-effect tube Q1 is connected with the output end of the second operational amplifier in a double operational amplifier U1, the second end of the resistor R1 is respectively connected with the second end of the capacitor C1 and the first end of the resistor R3, the second end of the resistor R2 is connected with the non-inverting input end of the first operational amplifier U1, the second end of the resistor R3 is connected with the inverting input end of the inverting, two ends of a resistor R4 are respectively connected with the inverting input end and the output end of a first operational amplifier in a double operational amplifier U1, the first end of a resistor R5 is connected with the non-inverting input end of a second operational amplifier in the double operational amplifier U1, the second end of the resistor R5 is grounded, the non-inverting input end of the second operational amplifier in the double operational amplifier U1 is further connected with a main control circuit to input a reference voltage, the output end of the first operational amplifier in the double operational amplifier U1 is connected with the inverting input end of the second operational amplifier, and the source of the field effect transistor Q1 and the pin No. 4 of the analog switch S1 are further connected with a differential amplification circuit.
Further, the differential amplification circuit comprises a resistor R6, a resistor R7, an adjustable resistor R8, a resistor R9, a capacitor C2, a capacitor C3 and an operational amplifier U2, wherein a first end of the resistor R6 and a first end of the resistor R7 are connected with the signal acquisition circuit, a second end of the resistor R6 and a second end of the resistor R7 are connected with the operational amplifier U2, a first end of the capacitor C2 and a first end of the capacitor C3 are both grounded, a second end of the capacitor C2 and a second end of the capacitor C3 are both connected with the operational amplifier U2, a fixed end and a sliding end of the adjustable resistor R8 are both connected with the operational amplifier U2, a first end of the resistor R9 is connected with the operational amplifier U2, and a second end of the resistor R9 is connected with the main control circuit.
Further, the first voltage stabilizing circuit comprises a resistor R10, a capacitor C4 and a voltage stabilizer U3, a first end of the resistor R10 is connected with the battery access port, a second end of the resistor R10 is respectively connected with a first end of the capacitor C4 and an input end of the voltage stabilizer U3, a second end of the capacitor C4 and a grounding end of the voltage stabilizer U3 are both grounded, an output end of the voltage stabilizer U3 is respectively connected with the signal acquisition circuit and the differential amplification circuit, and the output voltage of the voltage stabilizer U3 is 5V.
Further, the second voltage stabilizing circuit comprises a resistor R11, a capacitor C5 and a voltage stabilizer U4, a first end of the resistor R11 is connected with the battery access port, a second end of the resistor R11 is respectively connected with a first end of the capacitor C5 and an input end of the voltage stabilizer U4, a second end of the capacitor C5 and a ground end of the voltage stabilizer U4 are both grounded, an output end of the voltage stabilizer U4 is connected with the main control circuit, and an output voltage of the voltage stabilizer U4 is 3.3V.
Further, the battery access port comprises a battery interface J1 and a toggle switch U5, the negative electrode of the interface J1 is grounded, the positive electrode of the interface J1 is connected with a pin No. 3 of the toggle switch U5, a pin No. 1 of the toggle switch U5 is empty, and a pin No. 2 of the toggle switch U5 is respectively connected with the signal acquisition circuit, the first voltage stabilizing circuit and the second voltage stabilizing circuit.
Further, the battery access port also comprises a load port J2 which is connected with the battery interface J1 and is used for battery load access.
Further, the master control circuit comprises a single chip microcomputer U6, a test interface J3, a data interface J4, a crystal oscillator X1, a crystal oscillator X2, a capacitor C7 and a capacitor C8, wherein the test interface J3 and the data interface J4 are connected with the single chip microcomputer U6, two ends of the crystal oscillator X1 and two ends of the crystal oscillator X2 are connected with the single chip microcomputer U6, a first end of the capacitor C7 is connected with a first end of the crystal oscillator X1, a first end of the capacitor C8 is connected with a second end of the crystal oscillator X1, a second end of the capacitor C7 and a second end of the capacitor C8 are grounded, and the single chip microcomputer U6 is further connected with a signal acquisition circuit, a differential amplification circuit and a second voltage stabilizing circuit respectively.
Further, the main control circuit further comprises a reset module for controlling the reset of the single chip microcomputer U6, the reset module comprises a resistor R12, a capacitor C6 and a light touch switch SW2, the first end of the resistor R12 is connected with a second voltage stabilizing circuit, the second end of the resistor R12 is connected with the first end of the capacitor C6 and a reset pin of the single chip microcomputer U6, the second end of the capacitor C6 and the first end of the light touch switch SW2 are grounded, and the second end of the light touch switch SW2 is connected with the reset pin of the single chip microcomputer U6.
The utility model discloses following beneficial effect has:
the utility model discloses a detection circuitry of lithium cell internal resistance, adopt the signal acquisition circuit to carry out signal acquisition with the mode output of constant current discharge through the control lithium cell, the voltage signal who gathers is very stable, the precision of detection has been ensured, and carry out the difference amplification to the difference amplifier circuit with the signal transmission after gathering, the influence of common mode signal has been eliminated, avoided because the secondary sampling of master control circuit and the stack of producing the error, the precision of detection has been improved, and can not cause any damage to the lithium cell, can repeat many times and detect the lithium cell internal resistance.
In addition to the above-described objects, features and advantages, the present invention has other objects, features and advantages. The present invention will be described in further detail with reference to the drawings.
Drawings
The accompanying drawings, which are incorporated in and constitute a part of this application, are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification. In the drawings:
fig. 1 is a schematic block diagram of a detection circuit for internal resistance of a lithium battery according to a preferred embodiment of the present invention.
Fig. 2 is a circuit diagram of the main control circuit in fig. 1 according to the preferred embodiment of the present invention.
Fig. 3 is a schematic circuit diagram of the signal acquisition circuit in fig. 1 according to the preferred embodiment of the present invention.
Fig. 4 is a circuit schematic diagram of the differential amplifier circuit in fig. 1 according to the preferred embodiment of the present invention.
Fig. 5 is a circuit diagram of the first voltage regulator circuit in fig. 1 according to the preferred embodiment of the present invention.
Fig. 6 is a circuit diagram of the second voltage stabilizing circuit shown in fig. 1 according to the preferred embodiment of the present invention.
Fig. 7 is a schematic circuit diagram of the battery access port of fig. 1 in accordance with a preferred embodiment of the present invention.
The reference numbers illustrate:
11. a battery access port; 12. a signal acquisition circuit; 13. a differential amplifier circuit; 14. a first voltage stabilizing circuit; 15. a second voltage stabilizing circuit; 16. a master control circuit; 161. a reset module; 162. an indication circuit.
Detailed Description
The embodiments of the invention will be described in detail below with reference to the drawings, but the invention can be implemented in many different ways, which are defined and covered below.
As shown in FIG. 1, the preferred embodiment of the utility model provides a detection circuitry of lithium cell internal resistance adopts the internal resistance of the mode of control lithium cell constant current discharge to detect the lithium cell, has the advantage that detects the precision height, can not cause the damage to the lithium cell moreover, can carry out the repeated detection to the lithium cell. The detection circuit for the internal resistance of the lithium battery comprises a battery access port 11, a signal acquisition circuit 12, a differential amplification circuit 13, a first voltage stabilizing circuit 14, a second voltage stabilizing circuit 15 and a main control circuit 16, wherein the battery access port 11 is used for inserting the lithium battery, the battery access port 11 is respectively connected with the signal acquisition circuit 12, the first voltage stabilizing circuit 14 and the second voltage stabilizing circuit 15 so as to output the voltage of the lithium battery to the signal acquisition circuit 12, the first voltage stabilizing circuit 14 and the second voltage stabilizing circuit 15, the signal acquisition circuit 12 can control the constant current discharge of the lithium battery and acquire voltage signals, the first voltage stabilizing circuit 14 can output stable direct current voltage to the signal acquisition circuit 12 and the differential amplification circuit 13, the second voltage stabilizing circuit 15 can output stable direct current voltage to the main control circuit 16, wherein the direct current voltage output by the first voltage stabilizing circuit 14 is 5V, the dc voltage output by the second voltage stabilizing circuit 15 is 3.3V. The differential amplification circuit 13 is also respectively connected with the signal acquisition circuit 12 and the main control circuit 16, the differential amplification circuit 13 can carry out differential amplification processing on the voltage signal acquired by the signal acquisition circuit 12 and output the amplified signal to the main control circuit 16 for signal sampling, so that the influence of common-mode signals is eliminated, the superposition of errors caused by secondary sampling of the main control circuit 16 is avoided, and the detection accuracy is improved. The master control circuit 16 is also connected to the signal acquisition circuit 12 to provide a reference voltage to the signal acquisition circuit 12. It is understood that the first voltage regulator circuit 14 and the second voltage regulator circuit 15 may be omitted, and the signal acquisition circuit 12, the differential amplifier circuit 13 and the main control circuit 16 may be supplied with operating voltages by using a built-in power supply.
The utility model discloses a detection circuitry of lithium cell internal resistance, adopt signal acquisition circuit 12 control lithium cell to export with the mode that the constant current discharged and carry out voltage signal simultaneously and gather, the voltage signal who gathers is very stable, the precision of detection has been ensured, signal acquisition circuit 12 carries out the difference amplification to difference amplifier circuit 13 with the voltage signal transmission after gathering, the influence of common mode signal has been eliminated, avoided because the secondary sampling of master control circuit 16 and the stack of producing the error, the precision of detection has been improved, and can not cause any damage to the lithium cell, can repeat many times to detect the lithium cell internal resistance.
As shown in fig. 2, the main control circuit 16 includes a single chip microcomputer U6, a test interface J3, a data interface J4, a crystal oscillator X1, a crystal oscillator X2, a capacitor C7 and a capacitor C8, the test interface J3 and the data interface J4 are both connected to the single chip microcomputer U6, both ends of the crystal oscillator X1 and both ends of the crystal oscillator X2 are both connected to the single chip microcomputer U6, a first end of the capacitor C7 is connected to a first end of the crystal oscillator X1, a first end of the capacitor C8 is connected to a second end of the crystal oscillator X1, a second end of the capacitor C7 and a second end of the capacitor C8 are both grounded, the single chip microcomputer U6 is further connected to the signal acquisition circuit 12, the differential amplification circuit 13 and the second voltage regulator circuit 82915, and the crystal oscillator X1 and the crystal oscillator X2 are used to provide a clock frequency to the single chip microcomputer U6. It can be understood that, as a preferred mode, the model of the single chip microcomputer U6 is MSP430F169IPMR, the model of the test interface J3 is JTAG2 × 7, the model of the data interface J4 is Head-Female-2.54-1 × 4, the capacities of the capacitor C7 and the capacitor C8 are 1U, the frequency of the crystal oscillator X1 is 8MHz, and the frequency of the crystal oscillator X2 is 32768 Hz.
The main control circuit 16 further comprises a reset module 161 for controlling the reset of the single chip microcomputer U6, the reset module 161 comprises a resistor R12, a capacitor C6 and a light touch switch SW2, the first end of the resistor R12 is connected with the second voltage stabilizing circuit 15, the second end of the resistor R12 is connected with the first end of the capacitor C6 and the reset pin of the single chip microcomputer U6, the second end of the capacitor C6 and the first end of the light touch switch SW2 are grounded, and the second end of the light touch switch SW2 is connected with the reset pin of the single chip microcomputer U6.
In addition, the main control circuit 16 further includes an indication circuit 162, the indication circuit 162 includes a resistor R13 and a light emitting diode D1, a first end of the resistor R13 is connected to the output end of the second voltage stabilizing circuit 15, a second end of the resistor R13 is connected to the anode of the light emitting diode D1, and the cathode of the light emitting diode D1 is grounded. The resistance value of the resistor R13 is 1K omega, and the type of the light-emitting diode D1 is LED-White 0805.
As shown in fig. 3, the signal acquisition circuit 12 includes an analog switch S1, a dial switch SW1, a field effect transistor Q1, a capacitor C1, a resistor R1, a resistor R2, a resistor R3, a resistor R4, a resistor R5, and a dual operational amplifier U1, where the pin 1 of the analog switch S1 is connected to the single chip U6, the pin 2 of the analog switch S1 is connected to the first voltage stabilizing circuit 14, the pin 5 of the analog switch S1 is connected to the battery access port 11, the pin 4 of the analog switch S1 is connected to the first end of the capacitor C1, and the second end of the capacitor C1 is grounded. The first end of the toggle switch SW1 is connected with a No. 5 pin of the analog switch S1, the second end of the toggle switch SW1 is connected with the source electrode of the field-effect transistor Q1, the drain electrode of the field-effect transistor Q1 is respectively connected with the first end of the resistor R1 and the first end of the resistor R2, and the control electrode of the field-effect transistor Q1 is connected with the output end of the second operational amplifier in the dual operational amplifier U1. The second end of the resistor R1 is connected with the second end of the capacitor C1 and the first end of the resistor R3 respectively, the second end of the resistor R2 is connected with the non-inverting input end of the first operational amplifier in the dual operational amplifier U1, the second end of the resistor R3 is connected with the inverting input end of the first operational amplifier in the dual operational amplifier U1, two ends of the resistor R4 are connected with the inverting input end and the output end of the first operational amplifier in the dual operational amplifier U1 respectively, the first end of the resistor R5 is connected with the non-inverting input end of the second operational amplifier in the dual operational amplifier U1, the second end of the resistor R5 is grounded, the non-inverting input end of the second operational amplifier in the dual operational amplifier U1 is also connected with the single chip U6 to input a reference voltage, the output end of the first operational amplifier in the dual operational amplifier U1 is connected with the inverting input end of the second operational amplifier, the source of the field effect transistor Q1 and pin No. 4 of the analog switch S1 are also connected to the differential amplifier circuit 13. The dual operational amplifier U1 is also connected to the first regulator circuit 14.
The signal acquisition circuit 12 adopts a field effect transistor Q1 to realize constant current discharge of the lithium battery, the field effect transistor Q1 is a voltage control device, the input impedance of the voltage control device is very large, the control electrode has almost no leakage current, a constant current source using the field effect transistor Q1 has the advantages of high current precision and good stability, a resistor R1 is a current detection resistor with a very small value and is a milliohm-level resistor as with the internal resistance of the lithium battery, a resistor R2, a resistor R3, a resistor R5 and a first operational amplifier in a dual operational amplifier U1 form an inverting amplifier for amplifying the voltage at two ends of the current detection resistor R1 and then serve as the inverting input of a second operational amplifier in the dual operational amplifier U1, then the amplified voltage together with a reference voltage Vref input by a single chip microcomputer U6 and then output to the control electrode of the field effect transistor Q1 after passing through a second operational amplifier in the dual operational amplifier U1, so as to realize constant current discharge of the lithium battery, wherein the second operational amplifier U1 is connected to an ideal amplifier circuit, when the voltage division circuit is in the internal resistance voltage of the lithium battery, only a voltage drop circuit, the voltage drop of the lithium battery can be measured by a steep voltage drop of the voltage detection resistor R1.
It can be understood that, preferably, the analog switch S1 is of a model RS2101XC6, the dial switch SW1 is of a model BD01, the capacitor C1 has a capacity of 10uf, the resistor R1 has a resistance of 0.02 Ω, the resistors R2, R3, R4 and R5 all have a resistance of 1K Ω, the field-effect transistor Q1 is of a model IRLR8726PBF, and the dual operational amplifier U1 is of a model AD 8552.
As shown in fig. 4, the differential amplifier circuit 13 includes a resistor R6, a resistor R7, an adjustable resistor R8, a resistor R9, a capacitor C2, a capacitor C3, and an operational amplifier U2, a first end of the resistor R6 is connected to the source of the fet Q1, a first end of the resistor R7 is connected to the pin No. 4 of the analog switch S1, a second end of the resistor R6 is connected to the pin No. 2 of the operational amplifier U2, a second end of the resistor R7 is connected to the pin No. 3 of the operational amplifier U2, a first end of the capacitor C2 and a first end of the capacitor C3 are both grounded, a second end of the capacitor C2 is connected to the pin No. 2 of the operational amplifier U2, a second end of the capacitor C2 is connected to the pin No. 3 of the operational amplifier U2, a fixed end of the adjustable resistor R2 is connected to the pin No. 1 of the operational amplifier U2, a sliding end of the adjustable resistor R2 is connected to the pin No. 366 of the operational amplifier U2, the second end of the resistor R9 is connected with the single chip microcomputer U6 for signal sampling. And the No. 5 pin and the No. 7 pin of the operational amplifier U2 are both connected with the first voltage stabilizing circuit 14. It is understood that, preferably, the model of the operational amplifier U2 is AD620BRZ, the resistances of the resistor R6 and the resistor R7 are 1K Ω, the capacities of the capacitor C2 and the capacitor C3 are 1U, the total resistance of the adjustable resistor R8 is 50K Ω, and the resistance of the resistor R9 is 0R.
As shown in fig. 5, the first voltage stabilizing circuit 14 includes a resistor R10, a capacitor C4, and a voltage regulator U3, a first end of the resistor R10 is connected to the battery access port 11, a second end of the resistor R10 is connected to a first end of the capacitor C4 and an input end of the voltage regulator U3, both a second end of the capacitor C4 and a ground end of the voltage regulator U3 are grounded, an output end of the voltage regulator U3 is connected to the dual operational amplifier U1, the analog switch S1, and the operational amplifier U2, and the voltage regulator U3 may provide a 5V operating voltage for the dual operational amplifier U1, the analog switch S1, and the operational amplifier U2. It is understood that, preferably, the resistor R10 has a resistance of 1K Ω, the capacitor C4 has a capacitance of 1U, and the voltage regulator U3 has a model number HT7550-1-TO 92.
As shown in fig. 6, the second voltage stabilizing circuit 15 includes a resistor R11, a capacitor C5, and a voltage regulator U4, a first end of the resistor R11 is connected to the battery access port 11, a second end of the resistor R11 is connected to a first end of the capacitor C5 and an input end of the voltage regulator U4, both a second end of the capacitor C5 and a ground end of the voltage regulator U4 are grounded, an output end of the voltage regulator U4 is connected to the single chip microcomputer U6, and the voltage regulator U4 can provide a 3.3V working voltage for the single chip microcomputer U6. It can be understood that, preferably, the resistor R11 has a resistance of 1K Ω, the capacitor C5 has a capacitance of 1U, and the voltage regulator U4 has a model number HT7533-1-TO 92.
As shown in fig. 7, the battery access port 11 includes a battery interface J1 and a toggle switch U5, a negative electrode of the interface J1 is grounded, a positive electrode of the interface J1 is connected to a pin No. 3 of the toggle switch U5, a pin No. 1 of the toggle switch U5 is empty, and a pin No. 2 of the toggle switch U5 is connected to a first end of a resistor R10, a first end of the resistor R11, and a pin No. 5 of an analog switch S1, respectively. It is understood that the battery access port 11 preferably further includes a load port J2 connected to the battery interface J1 for accessing a battery load, so as to access other electrical loads during the detection process.
The utility model discloses a lithium cell internal resistance ' S detection circuitry ' S working process specifically is that the reference voltage of the non inverting input end of the second operational amplifier in the two operational amplifier U1 of control is 0 at first, thereby draw down the voltage of field effect transistor Q1 ' S control pole in order to close the field effect transistor, then open analog switch S1, thereby the voltage on electric capacity C1 is the output voltage of lithium cell again, close analog switch S1 again, singlechip U6 outputs reference voltage to two operational amplifier U1 simultaneously, utilize the voltage feedback at current detection resistance R1 both ends to realize constant current discharge, signal acquisition circuit 12 outputs two voltage signal Vout1 and Vout2 and carries out the difference amplification processing to difference discharge circuit 13, the signal after amplification is obtained through the signal sampling of singlechip U6 at last, can calculate the precipitous voltage drop △ U that appears in the constant current discharge process of lithium cell, thereby calculate the internal resistance R that obtains the lithium cell, R is △ U/I.
The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (10)
1. A detection circuit for internal resistance of lithium battery is characterized in that,
comprises a battery access port (11) for inserting a lithium battery, a signal acquisition circuit (12) for acquiring signals by controlling the lithium battery to discharge in a constant current mode, a differential amplification circuit (13) for carrying out differential amplification processing on the signals acquired by the signal acquisition circuit (12), a main control circuit (16) for carrying out signal sampling on the signals amplified by the differential amplification circuit (13) and for providing reference voltage for the signal acquisition circuit (12),
the signal acquisition circuit (12) is respectively connected with the battery access port (11) and the differential amplification circuit (13), the differential amplification circuit (13) is connected with the main control circuit (16), and the main control circuit (16) is also connected with the signal acquisition circuit (12).
2. The detection circuit for internal resistance of lithium battery as claimed in claim 1,
the battery charging system is characterized by further comprising a first voltage stabilizing circuit (14) and a second voltage stabilizing circuit (15) which are used for providing stable direct-current voltage, wherein the first voltage stabilizing circuit (14) and the second voltage stabilizing circuit (15) are both connected with the battery access port (11), the first voltage stabilizing circuit (14) is further connected with the signal acquisition circuit (12) and the differential amplification circuit (13) respectively, and the second voltage stabilizing circuit (15) is connected with the main control circuit (16).
3. The detection circuit for internal resistance of lithium battery as claimed in claim 1,
the signal acquisition circuit (12) comprises an analog switch S1, a dial switch SW1, a field effect transistor Q1, a capacitor C1, a resistor R1, a resistor R2, a resistor R3, a resistor R4, a resistor R5 and a double operational amplifier U1,
the pin 1 of the analog switch S1 is connected with a master control circuit (16), the pin 5 of the analog switch S1 is connected with a battery access port (11), the pin 4 of the analog switch S1 is connected with the first end of a capacitor C1, the second end of the capacitor C1 is grounded, the first end of a toggle switch SW1 is connected with the pin 5 of an analog switch S1, the second end of the toggle switch SW1 is connected with the source electrode of a field-effect tube Q1, the drain electrode of the field-effect tube Q1 is respectively connected with the first end of a resistor R1 and the first end of a resistor R2, the control electrode of the field-effect tube Q1 is connected with the output end of a second operational amplifier in a dual operational amplifier U1, the second end of the resistor R1 is respectively connected with the second end of the capacitor C1 and the first end of a resistor R3, the second end of the resistor R2 is connected with the non-phase input end of a first operational amplifier U1, and the second end of the resistor R3 is connected with the inverting operational amplifier 676726 of the second operational amplifier U1, two ends of a resistor R4 are respectively connected with the inverting input end and the output end of a first operational amplifier in a double operational amplifier U1, the first end of a resistor R5 is connected with the non-inverting input end of a second operational amplifier in the double operational amplifier U1, the second end of the resistor R5 is grounded, the non-inverting input end of the second operational amplifier in the double operational amplifier U1 is further connected with a main control circuit (16) to input a reference voltage, the output end of the first operational amplifier in the double operational amplifier U1 is connected with the inverting input end of the second operational amplifier, and the source of the field effect transistor Q1 and the pin No. 4 of the analog switch S35 1 are further connected with a differential amplification circuit (13).
4. The detection circuit for internal resistance of lithium battery as claimed in claim 1,
the differential amplification circuit (13) comprises a resistor R6, a resistor R7, an adjustable resistor R8, a resistor R9, a capacitor C2, a capacitor C3 and an operational amplifier U2, wherein a first end of the resistor R6 and a first end of the resistor R7 are connected with the signal acquisition circuit (12), a second end of the resistor R6 and a second end of the resistor R7 are connected with the operational amplifier U2, a first end of the capacitor C2 and a first end of the capacitor C3 are grounded, a second end of the capacitor C2 and a second end of the capacitor C3 are connected with the operational amplifier U2, a fixed end and a sliding end of the adjustable resistor R8 are connected with the operational amplifier U2, a first end of the resistor R9 is connected with the operational amplifier U2, and a second end of the resistor R9 is connected with the main control circuit (16).
5. The detection circuit of internal resistance of lithium battery as claimed in claim 2,
the first voltage stabilizing circuit (14) comprises a resistor R10, a capacitor C4 and a voltage stabilizer U3, the first end of the resistor R10 is connected with a battery access port (11), the second end of the resistor R10 is respectively connected with the first end of the capacitor C4 and the input end of the voltage stabilizer U3, the second end of the capacitor C4 and the grounding end of the voltage stabilizer U3 are both grounded, the output end of the voltage stabilizer U3 is respectively connected with the signal acquisition circuit (12) and the differential amplification circuit (13), and the output voltage of the voltage stabilizer U3 is 5V.
6. The detection circuit of internal resistance of lithium battery as claimed in claim 2,
the second voltage stabilizing circuit (15) comprises a resistor R11, a capacitor C5 and a voltage stabilizer U4, the first end of the resistor R11 is connected with the battery access port (11), the second end of the resistor R11 is respectively connected with the first end of the capacitor C5 and the input end of the voltage stabilizer U4, the second end of the capacitor C5 and the grounding end of the voltage stabilizer U4 are grounded, the output end of the voltage stabilizer U4 is connected with the main control circuit (16), and the output voltage of the voltage stabilizer U4 is 3.3V.
7. The detection circuit of internal resistance of lithium battery as claimed in claim 2,
the battery access port (11) comprises a battery interface J1 and a toggle switch U5, the negative electrode of the interface J1 is grounded, the positive electrode of the interface J1 is connected with a pin No. 3 of the toggle switch U5, a pin No. 1 of the toggle switch U5 is empty, and a pin No. 2 of the toggle switch U5 is respectively connected with the signal acquisition circuit (12), the first voltage stabilizing circuit (14) and the second voltage stabilizing circuit (15).
8. The detection circuit for internal resistance of a lithium battery as claimed in claim 7,
the battery access port (11) also comprises a load port J2 which is connected with the battery interface J1 and is used for accessing a battery load.
9. The detection circuit of internal resistance of lithium battery as claimed in claim 2,
the main control circuit (16) comprises a single chip microcomputer U6, a test interface J3, a data interface J4, a crystal oscillator X1, a crystal oscillator X2, a capacitor C7 and a capacitor C8, wherein the test interface J3 and the data interface J4 are connected with a single chip microcomputer U6, two ends of the crystal oscillator X1 and two ends of the crystal oscillator X2 are connected with the single chip microcomputer U6, a first end of the capacitor C7 is connected with a first end of the crystal oscillator X1, a first end of the capacitor C8 is connected with a second end of the crystal oscillator X1, a second end of the capacitor C7 and a second end of the capacitor C8 are grounded, and the single chip microcomputer U6 is further connected with a signal acquisition circuit (12), a differential amplification circuit (13) and a second voltage stabilizing circuit (15) respectively.
10. The detection circuit for internal resistance of a lithium battery as claimed in claim 9,
the main control circuit (16) further comprises a reset module (161) for controlling the reset of the single chip microcomputer U6, the reset module (161) comprises a resistor R12, a capacitor C6 and a light touch switch SW2, the first end of the resistor R12 is connected with a second voltage stabilizing circuit (15), the second end of the resistor R12 is connected with the first end of the capacitor C6 and a reset pin of the single chip microcomputer U6 respectively, the second end of the capacitor C6 and the first end of the light touch switch SW2 are grounded, and the second end of the light touch switch SW2 is connected with the reset pin of the single chip microcomputer U6.
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| CN201920855608.0U CN210514567U (en) | 2019-06-06 | 2019-06-06 | Detection circuit for internal resistance of lithium battery |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111580007A (en) * | 2020-07-06 | 2020-08-25 | 深圳市汇业达通讯技术有限公司 | Circuit and method for detecting internal resistance of storage battery |
| CN113189468A (en) * | 2021-05-13 | 2021-07-30 | 中国工程物理研究院电子工程研究所 | Health state on-line monitoring circuit and system of power device |
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2019
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111580007A (en) * | 2020-07-06 | 2020-08-25 | 深圳市汇业达通讯技术有限公司 | Circuit and method for detecting internal resistance of storage battery |
| CN113189468A (en) * | 2021-05-13 | 2021-07-30 | 中国工程物理研究院电子工程研究所 | Health state on-line monitoring circuit and system of power device |
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