A lithium battery voltage and internal resistance detection circuit based on digital orthogonal phase-locked technology

Abstract

The present invention provides a lithium battery voltage and internal resistance detection circuit based on digital orthogonal phase-locked technology in the field of lithium battery detection technology, including a main control module, a signal source module, an AC constant current source module, an ADC module, an over-range state detection module, a voltage sampling module, a filter amplifier module and an internal resistance sampling module; the input end of the signal source module is connected to the main control module, and the output end is connected to the AC constant current source module and the ADC module; the input end of the over-range state detection module is connected to the voltage sampling module and the filter amplifier module, and the output end is connected to the main control module; the output end of the internal resistance sampling module is connected to the filter amplifier module; the input end of the ADC module is connected to the signal source module, the voltage sampling module and the filter amplifier module, and the output end is connected to the main control module. The advantages of the present invention are: the lithium battery detection speed is greatly improved, and the lithium battery detection cost is greatly reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of lithium battery detection, and in particular to a lithium battery voltage and internal resistance detection circuit based on digital orthogonal phase-locked technology. Background Art

[0002] With the rise and development of new energy, lithium batteries, as green high-energy chemical power sources, have been widely used in the new energy industry with the advantages of high energy, high power, and low cost. In order to ensure the safety of lithium batteries, a series of tests are required before leaving the factory.

[0003] Voltage and internal resistance are essential test items, and the detection of internal resistance is particularly important. For the detection of internal resistance, there are traditionally phase-sensitive detection method and digital orthogonal phase-locked method, both of which are based on the testing principle of AC injection method.

[0004] The phase-sensitive detection method converts the AC internal resistance of the lithium battery into a DC signal for detection. It has the disadvantage of taking a long time to measure, and the measured value is easily interfered by low-frequency noise in the field environment, making it impossible to know the impedance angle of the lithium battery. In order to improve the detection efficiency, the digital orthogonal phase-locked method is gradually adopted; however, the digital orthogonal phase-locked method uses the lithium battery response signal and the synchronization signal as a reference and processes them in the digital domain. Although the response speed is fast, the performance requirements of the conversion chip and the processor are high, which leads to a high hardware cost of the detection equipment.

[0005] Therefore, how to provide a lithium battery voltage and internal resistance detection circuit based on digital orthogonal phase-locked technology to improve the lithium battery detection speed and reduce the lithium battery detection cost has become a technical problem that needs to be solved urgently. Summary of the invention

[0006] The technical problem to be solved by the present invention is to provide a lithium battery voltage and internal resistance detection circuit based on digital orthogonal phase-locked technology, so as to improve the lithium battery detection speed and reduce the lithium battery detection cost.

[0007] The present invention is implemented as follows: a lithium battery voltage and internal resistance detection circuit based on digital orthogonal phase-locked technology, including a main control module, a signal source module, an AC constant current source module, an ADC module, an over-range state detection module, a voltage sampling module, a filtering and amplifying module and an internal resistance sampling module;

[0008] The input end of the signal source module is connected to the main control module, and the output end is connected to the AC constant current source module and the ADC module; the input end of the over-range state detection module is connected to the voltage sampling module and the filter amplification module, and the output end is connected to the main control module; the output end of the internal resistance sampling module is connected to the filter amplification module; the input end of the ADC module is connected to the signal source module, the voltage sampling module and the filter amplification module, and the output end is connected to the main control module.

[0009] Further, the signal source module includes an op amp U17A, an op amp U17B, an op amp U18A, an op amp U18B, an op amp U21A, an op amp U23B, a resistor R88, a resistor R90, a resistor R94, a resistor R98, a resistor R100, a resistor R104, a resistor R105, a resistor R113, a resistor R118, a resistor R126, a resistor R131, a resistor R132, a resistor R133, a resistor R151, a resistor R152, a resistor R169, a resistor R176, a resistor R177, a resistor R179, a resistor R180, a resistor R298, a resistor R301, a resistor R302, a capacitor C102, a capacitor C104, a capacitor C112, a capacitor C114, a capacitor C115, a capacitor C116, a capacitor C118, a capacitor C157, a capacitor C158, a capacitor C159, a capacitor C169 and a linear optocoupler U19;

[0010] One end of the resistor R90 is connected to the resistor R131 and the main control module, and the other end is connected to the pin 3 of the operational amplifier U17A; the pin 1 of the operational amplifier U17A is connected to the capacitor C114 and the resistor R94, and the pin 2 is connected to the resistor R100, the capacitor C114 and the pin 4 of the linear optocoupler U19; the pin 2 of the linear optocoupler U19 is connected to the resistor R94, the pin 3 is connected to the capacitor C112, the pin 5 is connected to the resistor R104 and the resistor R113, and the pin 6 is connected to the capacitor C104;

[0011] Pin 1 of the operational amplifier U21A is connected to capacitor C115, resistor R88, capacitor C102 and pin 2 of the operational amplifier U21A, and pin 3 is connected to resistor R105 and capacitor C118; the resistor R105 is connected to resistor R104 and capacitor C102; pin 5 of the operational amplifier U23B is connected to resistor R118 and capacitor C116, and pin 6 is connected to resistor R126, resistor R98, an AC constant current source module and pin 7 of the operational amplifier U23B; the capacitor C116 is connected to capacitor C115 and resistor R98.

[0012] Further, the AC constant current source module includes a resistor R75, a resistor R78, a resistor R79, a resistor R91, a resistor R95, a resistor R96, a resistor R97, a resistor R99, a resistor R101, a resistor R103, a resistor R106, a resistor R107, a resistor R112, a resistor R119, a resistor R134, a resistor R146, a resistor R153, a resistor R154, a resistor R155, a capacitor C106, a capacitor C135, an operational amplifier U20A, an operational amplifier U20B, an operational amplifier U23A, a light emitting diode LED4, a diode D13, a transistor Q4, a conversion relay K4, a clamping diode D9 and a clamping diode D10;

[0013] One end of the resistor R101 is connected to the signal source module, and the other end is connected to the resistor R91 and the pin 3 of the operational amplifier U23A; the pin 1 of the operational amplifier U23A is connected to the resistor R96, the resistor R119 and the pin 3 of the switching relay K4, and the pin 2 is connected to the resistor R106 and the resistor R119;

[0014] Pin 1 of the switching relay K4 is connected to the resistor R146, the output end of the diode D13, the resistor R153 and the capacitor C135, pin 4 is connected to the resistor R99, pin 5 is connected to the resistor R134, pin 6 is connected to the resistor R134, pin 8 is connected to the input end of the diode D13, the output end of the light emitting diode LED4 and the collector of the transistor Q4; the base of the transistor Q4 is connected to the resistor R154 and the resistor R155, and the emitter is connected to the resistor R155; the resistor R153 is connected to the input end of the light emitting diode LED4;

[0015] Pin 5 of the operational amplifier U20B is connected to resistor R95 and resistor R79, pin 6 is connected to resistor R99 and resistor R112, and pin 7 is connected to resistor R112, resistor R97, resistor R107 and pin 3 of clamping diode D10; pin 1 of the operational amplifier U20A is connected to resistor R75, resistor R79 and pin 2 of the operational amplifier U20A, and pin 3 is connected to resistor R78 and pin 3 of clamping diode D9; the resistor R103 is respectively connected to resistor R78, resistor R97, resistor R107 and capacitor C106.

[0016] Further, the ADC module includes a voltage input unit, an internal resistance input unit, a signal input unit and an analog-to-digital conversion unit;

[0017] One end of the voltage input unit is connected to the voltage sampling module, and the other end is connected to the analog-to-digital conversion unit; one end of the internal resistance input unit is connected to the filtering and amplifying module, and the other end is connected to the analog-to-digital conversion unit; one end of the signal input unit is connected to the signal source module, and the other end is connected to the analog-to-digital conversion unit; the analog-to-digital conversion unit is connected to the main control module.

[0018] Further, the voltage input unit includes an operational amplifier U15, a resistor R67, a resistor R68, a resistor R73, a resistor R74, a resistor R81, a resistor R82, a resistor R84, a capacitor C100 and a clamping diode D11;

[0019] Pin 1 of the operational amplifier U15 is connected to resistor R74 and resistor R82, pin 4 is connected to resistor R82 and resistor R81, pin 5 is connected to resistor R67 and resistor R68, pin 7 is connected to resistor R84, and pin 8 is connected to resistor R68, resistor R73 and pin 3 of clamping diode D11; the resistor R73 and resistor R74 are respectively connected to the voltage sampling module; one end of the capacitor C100 is connected to resistor R67 and the analog-to-digital conversion unit, and the other end is connected to resistor R81 and the analog-to-digital conversion unit;

[0020] The internal resistance input unit includes an operational amplifier U22, a resistor R92, a resistor R93, a resistor R102, a resistor R108, a resistor R115, a resistor R117, a resistor R120, a capacitor C111 and a clamping diode D12;

[0021] Pin 1 of the operational amplifier U22 is connected to resistor R108 and resistor R115, pin 4 is connected to resistor R115 and resistor R117, pin 5 is connected to resistor R92 and resistor R93, pin 7 is connected to resistor R120, and pin 8 is connected to resistor R93, resistor R102, and pin 3 of clamping diode D12; the resistor R102 and resistor R108 are respectively connected to the filter amplification module; one end of the capacitor C111 is connected to resistor R92 and the analog-to-digital conversion unit, and the other end is connected to resistor R117 and the analog-to-digital conversion unit;

[0022] The signal input unit includes an operational amplifier U25, a resistor R127, a resistor R128, a resistor R129, a resistor R135, a resistor R136, a resistor R138, a resistor R139, a capacitor C121 and a clamping diode D14;

[0023] Pin 1 of the operational amplifier U15 is connected to resistor R74 and resistor R82, pin 4 is connected to resistor R82 and resistor R81, pin 5 is connected to resistor R67 and resistor R68, pin 7 is connected to resistor R84, and pin 8 is connected to resistor R68, resistor R73 and pin 3 of clamping diode D11; the resistor R73 and resistor R74 are respectively connected to the voltage sampling module; one end of the capacitor C100 is connected to resistor R67 and the analog-to-digital conversion unit, and the other end is connected to resistor R81 and the analog-to-digital conversion unit.

[0024] Further, the analog-to-digital conversion unit includes an analog-to-digital conversion chip U16, a resistor R69, a resistor R70, a resistor R83, a resistor R85, a resistor R86, a resistor R89, a resistor R111, a capacitor C99, a capacitor C103, a capacitor C107, a capacitor C108, a capacitor C109, a capacitor C110, a capacitor C117, a resistor group R76, a resistor group R77 and a resistor group R87;

[0025] Pins 1 and 2 of the analog-to-digital conversion chip U16 are connected to the voltage input unit, pins 3 and 4 are connected to the internal resistance input unit, pins 5 and 6 are connected to the signal input unit, pin 7 is connected to the resistor R86, pin 8 is connected to the resistor R89, pin 9 is connected to the capacitor C109 and the capacitor C110, pin 12 is connected to one end of the capacitor C107, pin 13 is connected to the other end of the capacitor C107, pin 14 is connected to the resistor R111 and the capacitor C117, pins 15 and 16 are connected to the capacitor C108, pins 17, 18, and 19 are connected to the resistor group R87, pins 20, 21, 22, and 23 are connected to the resistor group R76, pin 27 is connected to one end of the capacitor C99 and grounded, pin 28 is connected to the other end of the capacitor C99, pin 29 is connected to the resistor R70, the capacitor C98, and the main control module, pin 30 is connected to the resistor R70, and pin 31 is connected to the resistor R69;

[0026] The resistor group R87 is connected to the capacitor C103, the resistor R85 and the main control module; one end of the resistor group R77 is connected to the resistor group R76, and the other end is connected to the resistor R83 and the main control module.

[0027] Further, the over-range state detection module includes a voltage detection unit and an internal resistance detection unit; one end of the voltage detection unit is connected to the voltage sampling module, and the other end is connected to the main control module; one end of the internal resistance detection unit is connected to the filter amplification module, and the other end is connected to the main control module;

[0028] The voltage detection unit includes a comparator chip U35A, a diode D31, a resistor R110, a resistor R228, a resistor R231, a resistor R238, a resistor R239, a resistor R242, a resistor R243 and a resistor R246;

[0029] Pins 1 and 7 of the comparator chip U35A are connected to resistors R238, R110 and R239, pins 2 and 5 are connected to the voltage sampling module, pin 3 is connected to resistors R238, R231 and R243, and pin 6 is connected to resistors R239, R242 and R246; one end of the resistor R228 is connected to the main control module, and the other end is connected to the resistor R110 and the output end of the diode D31; the input ends of the resistor R243, the resistor R246 and the diode D31 are all grounded;

[0030] The internal resistance detection unit includes a comparator chip U34A, an inverter chip U31, an inverter chip U32, a diode D16, a diode D25, a resistor R109, a resistor R181, a resistor R186, a resistor R187, a resistor R191, a resistor R195, a resistor R199, a resistor R212, a resistor R216 and a capacitor C164;

[0031] Pins 1 and 7 of the comparator chip U34A are connected to resistors R191, R109 and R195, pins 2 and 5 are connected to the filter amplifier module, pin 3 is connected to resistors R186 and R212, and pin 6 is connected to resistors R195, R199 and R216; one end of the resistor R181 is connected to the main control module, and the other end is connected to the resistor R109, the output end of the diode D25 and pin 2 of the inverter chip U31. ; Pin 4 of the inverter chip U31 is connected to the input end of the diode D16, and pin 5 is connected to the main control module; Pin 2 of the inverter chip U32 is connected to the output end of the resistor R187, the capacitor C164 and the diode D16, and pin 4 is connected to the main control module; the resistor R212, the resistor R216, the input end of the diode D25, pin 3 of the inverter chip U31, the capacitor C164, the resistor R187 and pin 3 of the inverter chip U32 are all grounded.

[0032] Further, the voltage sampling module includes a resistor R3, a resistor R6, a resistor R8, a resistor R9, a resistor R10, a resistor R11, a resistor R12, a resistor R16, a resistor R17, a resistor R19, a resistor R20, a resistor R21, a resistor R22, a resistor R23, a resistor R24, a resistor R29, a resistor R31, a resistor R32, a resistor R33, a resistor R34, a resistor R35, a resistor R38, a resistor R39, a resistor R40, a resistor R41, a resistor R42, a resistor R43, a resistor R44, a resistor R45, a resistor R46, a resistor R50, a resistor R51, a resistor R52, a resistor R53, a resistor R54 , a resistor R56, a resistor R57, a resistor R58, a resistor R130, a capacitor C31, a capacitor C32, a capacitor C37, a capacitor C53, a capacitor C59, a capacitor C61, a capacitor C64, a capacitor C66, a capacitor C70, a capacitor C71, a capacitor C82, a capacitor C83, a clamping diode D1, a clamping diode D2, a clamping diode D4, an operational amplifier U3A, an operational amplifier U4, an operational amplifier U12A, a linear optocoupler U9, a light emitting diode LED2, a light emitting diode LED3, a diode D5, a diode D6, a transistor Q2, a transistor Q3, a conversion relay K1, a conversion relay K2, an AND gate chip U5 and an AND gate chip U8;

[0033] One end of the resistor R9 is connected to the resistor R8, and the other end is connected to the resistor R10; one end of the resistor R11 is connected to the resistor R10, and the other end is connected to the resistor R12; pin 2 of the operational amplifier U4 is connected to the resistor R6, the capacitor C53, the resistor R24 ​​and the clamping diode D2, pin 3 is connected to the resistor R3, the resistor R12, the capacitor C32 and the clamping diode D1, and pin 6 is connected to the resistor R16, the resistor R6, the capacitor C53 and the resistor R38; one end of the resistor R21 is connected to the resistor R20, and the other end is connected to the resistor R22; one end of the resistor R23 is connected to the resistor R22, and the other end is connected to the resistor R24;

[0034] Pin 1 of the operational amplifier U3A is connected to resistor R39 and capacitor C64, pin 2 is connected to resistor R42, capacitor C64 and pin 4 of linear optocoupler U9, and pin 3 is connected to resistor R38; pin 2 of the linear optocoupler U9 is connected to resistor R39, pin 3 is connected to capacitor C66, pin 5 is connected to resistor R50, capacitor C70 and resistor R44, and pin 6 is connected to capacitor C59; resistor R50 is connected to capacitor C70 and grounded;

[0035] Pin 1 of the operational amplifier U12A is connected to resistor R46, resistor R43 and resistor R130, pin 2 is connected to resistor R35 and capacitor C61, and pin 3 is connected to resistor R45 and capacitor C71; the resistor R45 is connected to resistor R44 and capacitor C61; one end of the resistor R56 is connected to resistor R46 and grounded, and the other end is connected to the ADC module; the resistor R43 is connected to the clamping diode D4 and the ADC module; the resistor R130 is connected to the over-range state detection module;

[0036] Pin 1 of the switching relay K1 is connected to the resistor R40, the output end of the diode D5, the resistor R53 and the capacitor C82, pin 3 is connected to the resistor R31, pin 4 is connected to the resistor R11 and the resistor R12, pin 5 is connected to the resistor R23 and the resistor R24, pin 6 is connected to the resistor R32, pin 8 is connected to the input end of the diode D5, the output end of the light emitting diode LED2 and the collector of the transistor Q2; the resistor R53 is connected to the input end of the light emitting diode LED2; one end of the resistor R57 is connected to the resistor R51 and the base of the transistor Q2, and the other end is connected to the emitter of the transistor Q2;

[0037] Pin 1 of the switching relay K2 is connected to the output end of the resistor R41, the resistor R54, the capacitor C83 and the diode D6, pin 3 is connected to the resistor R33, pin 6 is connected to the resistor R34, pin 8 is connected to the input end of the diode D6, the output end of the light emitting diode LED3 and the collector of the transistor Q3; the resistor R54 is connected to the input end of the light emitting diode LED3; one end of the resistor R58 is connected to the resistor R52 and the base of the transistor Q3, and the other end is connected to the emitter of the transistor Q3;

[0038] Pin 1 of the AND gate chip U5 is connected to resistor R52, pin 2 is connected to resistor R17, pin 4 is connected to resistor R19, and pin 5 is connected to capacitor C31; pin 1 of the AND gate chip U8 is connected to resistor R19, pin 2 is connected to resistor R29, pin 4 is connected to resistor R51, and pin 5 is connected to capacitor C37.

[0039] Further, the filtering and amplifying module includes a resistor R14, a resistor R25, a resistor R163, a resistor R202, a resistor R234, a resistor R240, a resistor R241, a resistor R244, a resistor R245, a resistor R255, a resistor R260, a resistor R270, a capacitor C68, a capacitor C190, a capacitor C197, a capacitor C199, a capacitor C200, an operational amplifier U39A, an operational amplifier U39B, an operational amplifier U44A and an operational amplifier U44B;

[0040] Pin 6 of the operational amplifier U39B is connected to resistor R25, resistor R163 and capacitor C68, and pin 7 is connected to resistor R14, resistor R163, ADC module and over-range state detection module; pin 1 of the operational amplifier U39A is connected to resistor R25, resistor R202 and resistor R270, and pin 2 is connected to resistor R255 and resistor R270; pins 1 and 2 of the operational amplifier U44A are both connected to resistor R255, resistor R241 and resistor R260, and pin 3 is connected to resistor R234 and capacitor C199;

[0041] One end of the capacitor C197 is connected to the capacitor C199 and the resistor R260, and the other end is connected to the capacitor C190, the resistor R240 and the pins 6 and 7 of the operational amplifier U44B; the pin 5 of the operational amplifier U44B is connected to the capacitor C200 and the resistor R244; one end of the resistor R245 is connected to the resistor R244 and the capacitor C190, and the other end is connected to the internal resistance sampling module.

[0042] Further, the internal resistance sampling module includes an operational amplifier U37A, an operational amplifier U37B, an operational amplifier U38, a resistor R223, a resistor R224, a resistor R225, a resistor R226, a resistor R227, a resistor R236, a resistor R237, a resistor R247, a resistor R261, a resistor R262, a resistor R263, a resistor R269, a capacitor C187, a capacitor C189, a capacitor C191, a capacitor C198, a capacitor C207, a high-frequency magnetic bead L14, a high-frequency magnetic bead L16, a transient suppression diode D20, a transient suppression diode D24, a clamping diode D21, a clamping diode D22, a common-mode inductor L15 and a fuse F1;

[0043] Pin 1 of the operational amplifier U38 is connected to the resistor R227, the capacitor C189 and the capacitor C191, pin 4 is connected to the resistor R237, the capacitor C191 and the capacitor C198, pin 6 is connected to the resistor R236 and grounded, and pin 7 is connected to the resistor R236 and the filter amplifier module;

[0044] One end of the high-frequency magnetic bead L14 is connected to the resistor R227, and the other end is connected to the resistor R223, the resistor R226 and the pin 7 of the operational amplifier U37B; the pin 5 of the operational amplifier U37B is connected to the resistor R224 and the transient suppression diode D20, and the pin 6 is connected to the resistor R226; one end of the resistor R225 is connected to the resistor R224 and the pin 3 of the clamping diode D21, and the other end is connected to the resistor R222 and the capacitor C187;

[0045] One end of the high-frequency magnetic bead L16 is connected to the resistor R237, and the other end is connected to the resistor R247, the resistor R263 and the pin 1 of the operational amplifier U37A; the pin 3 of the operational amplifier U37A is connected to the resistor R261 and the transient suppression diode D24, and the pin 2 is connected to the resistor R247; one end of the resistor R262 is connected to the resistor R261 and the pin 3 of the clamping diode D22, and the other end is connected to the resistor R269 and the capacitor C207;

[0046] Pin 1 of the common mode inductor L15 is connected to the capacitor C207 , pin 2 is connected to the fuse F1 , and pin 4 is connected to the capacitor C187 .

[0047] The advantages of the present invention are:

[0048] 1. Only one main control module (a single-chip microcomputer with DSP function) is used to set the current reference waveform output by the signal source module and use it for orthogonal phase-locked calculation. A high-resolution ADC module is used to ensure the synchronization of the sampling data. The voltage sampling module and the filter amplifier module are set to perform multi-level sampling of the AC internal resistance and voltage of the battery to be tested. Under the premise of ensuring the detection accuracy, the circuit cost is greatly reduced, and ultimately the lithium battery detection speed is greatly improved, and the lithium battery detection cost is greatly reduced.

[0049] 2. By setting up the main control module for process control and complex digital operations in the internal resistance measurement process, it not only provides an efficient, high-precision, low-cost measurement method for the AC internal resistance test in the lithium battery test, but also can collect the voltage of the battery cell / battery pack in grades, which is convenient for integration with the industrial test system, and can accurately obtain the open circuit voltage, AC internal resistance and impedance angle of the battery to be tested. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] The present invention will be further described below in conjunction with embodiments with reference to the accompanying drawings.

[0051] Figure 1 The present invention is a circuit principle block diagram of a lithium battery voltage and internal resistance detection circuit based on digital orthogonal phase-locked technology.

[0052] Figure 2 It is a circuit principle block diagram of the ADC module of the present invention.

[0053] Figure 3 It is a circuit principle block diagram of the over-range state detection module of the present invention.

[0054] Figure 4 It is a circuit diagram of the signal source module of the present invention.

[0055] Figure 5 It is a circuit diagram of the AC constant current source module of the present invention.

[0056] Figure 6 It is a circuit diagram of the ADC module of the present invention.

[0057] Figure 7 It is a circuit diagram of the over-range state detection module of the present invention.

[0058] Figure 8 It is a circuit diagram of the voltage sampling module of the present invention.

[0059] Fig. 9 It is a circuit diagram of the filtering and amplifying module of the present invention.

[0060] Fig.10 It is a circuit diagram of the internal resistance sampling module of the present invention.

[0061] Marking Description:

[0062] 100-A lithium battery voltage and internal resistance detection circuit based on digital orthogonal phase-locked technology, 1-main control module, 2-signal source module, 3-AC constant current source module, 4-ADC module, 5-overrange state detection module, 6-voltage sampling module, 7-filtering and amplifying module, 8-internal resistance sampling module, 9-battery to be tested, 41-voltage input unit, 42-internal resistance input unit, 43-signal input unit, 44-analog-to-digital conversion unit, 51-voltage detection unit, 52-internal resistance detection unit. DETAILED DESCRIPTION

[0063] The embodiment of the present invention provides a lithium battery voltage and internal resistance detection circuit 100 based on digital orthogonal phase-locked technology, which solves the technical problems of long measurement time of the phase-sensitive detection method in the prior art and high hardware cost of the digital orthogonal phase-locked method, thereby achieving the technical effect of greatly improving the lithium battery detection speed and greatly reducing the lithium battery detection cost.

[0064] In order to better understand the above technical solution, the above technical solution will be described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0065] Please refer to Figures 1 to 10 As shown, a preferred embodiment of a lithium battery voltage and internal resistance detection circuit 100 based on digital orthogonal phase-locked technology of the present invention includes a main control module 1, a signal source module 2, an AC constant current source module 3, an ADC module 4, an over-range state detection module 5, a voltage sampling module 6, a filtering and amplifying module 7 and an internal resistance sampling module 8;

[0066] The main control module 1 is a single-chip microcomputer with DSP function, which is used to execute control logic and data operation processing, that is, to generate a current waveform reference signal, a gear switching signal, a relay control signal, receive a detection signal, and communicate with an ADC chip, and perform digital signal processing to calculate the AC internal resistance, phase angle, and the voltage of the battery 9 to be tested. In specific implementation, it is sufficient to select a single-chip microcomputer that can realize this function from the prior art, and it is not limited to any model, such as the STM32F103 series of single-chip microcomputers of ST Company, and the control program is well known to those skilled in the art, which can be obtained by those skilled in the art without creative labor; the signal source module 2 is used to generate a reference current waveform; the AC constant current source module 3 is used to amplify the output power; the ADC module 4 is used to perform analog-to-digital conversion of the measurement signal; the over-range state detection module 5 is used to generate a gear switching judgment signal; the voltage sampling module 6 is used to collect the voltage of the battery 9 to be tested; the filtering and amplifying module 7 is used to filter out noise and amplify the signal to an appropriate size; the internal resistance sampling module 8 is used to obtain the differential signal at both ends of the battery 9 to be tested.

[0067] The input end of the signal source module 2 is connected to the main control module 1, and the output end is connected to the AC constant current source module 3 and the ADC module 4; the input end of the over-range state detection module 5 is connected to the voltage sampling module 6 and the filter amplification module 7, and the output end is connected to the main control module 1; the output end of the internal resistance sampling module 8 is connected to the filter amplification module 7; the input end of the ADC module 4 is connected to the signal source module 2, the voltage sampling module 6 and the filter amplification module 7, and the output end is connected to the main control module 1.

[0068] The signal source module 2 includes an operational amplifier U17A, an operational amplifier U17B, an operational amplifier U18A, an operational amplifier U18B, an operational amplifier U21A, an operational amplifier U23B, a resistor R88, a resistor R90, a resistor R94, a resistor R98, a resistor R100, a resistor R104, a resistor R105, a resistor R113, a resistor R118, a resistor R126, a resistor R131, a resistor R132, a resistor R133, a resistor R151, and a resistor R157. A resistor R152, a resistor R169, a resistor R176, a resistor R177, a resistor R179, a resistor R180, a resistor R298, a resistor R301, a resistor R302, a capacitor C102, a capacitor C104, a capacitor C112, a capacitor C114, a capacitor C115, a capacitor C116, a capacitor C118, a capacitor C157, a capacitor C158, a capacitor C159, a capacitor C169 and a linear optocoupler U19;

[0069] The main control module 1 generates a fitted fixed-frequency sinusoidal waveform STM_32_DA input signal source module 2, and obtains a relatively pure sinusoidal signal source SIG_SOURCE_OUT after the linear optocoupler U19 and a series of filtering processes; at the same time, after filtering and smoothing, STM_32_DA also generates a reference differential signal Is+ and Is- for digital orthogonal phase-locked operation and sends it to the ADC module 4.

[0070] One end of the resistor R90 is connected to the resistor R131 and the main control module 1, and the other end is connected to the pin 3 of the operational amplifier U17A; the pin 1 of the operational amplifier U17A is connected to the capacitor C114 and the resistor R94, and the pin 2 is connected to the resistor R100, the capacitor C114 and the pin 4 of the linear optocoupler U19; the pin 2 of the linear optocoupler U19 is connected to the resistor R94, the pin 3 is connected to the capacitor C112, the pin 5 is connected to the resistor R104 and the resistor R113, and the pin 6 is connected to the capacitor C104;

[0071] Pin 1 of the operational amplifier U21A is connected to capacitor C115, resistor R88, capacitor C102 and pin 2 of the operational amplifier U21A, and pin 3 is connected to resistor R105 and capacitor C118; the resistor R105 is connected to resistor R104 and capacitor C102; pin 5 of the operational amplifier U23B is connected to resistor R118 and capacitor C116, and pin 6 is connected to resistor R126, resistor R98, AC constant current source module 3 and pin 7 of the operational amplifier U23B; the capacitor C116 is connected to capacitor C115 and resistor R98.

[0072] The AC constant current source module 3 includes a resistor R75, a resistor R78, a resistor R79, a resistor R91, a resistor R95, a resistor R96, a resistor R97, a resistor R99, a resistor R101, a resistor R103, a resistor R106, a resistor R107, a resistor R112, a resistor R119, a resistor R134, a resistor R146, a resistor R153, a resistor R154, a resistor R155, a capacitor C106, a capacitor C135, an operational amplifier U20A, an operational amplifier U20B, an operational amplifier U23A, a light emitting diode LED4, a diode D13, a transistor Q4, a conversion relay K4, a clamping diode D9 and a clamping diode D10;

[0073] That is, the AC constant current source module 3 includes a main circuit switch, a power amplifier circuit and a current limiting resistor; the function of the power amplifier circuit is to load the output SIG_SOURCE_OUT of the signal source module 2 to both ends of the resistor R97 and the resistor R107 after amplification. According to the "virtual disconnection" principle of the operational amplifier, there is almost no current flowing through the resistor R78, and the resistance value of the resistor R103 is much larger than the internal resistance of the battery 9 to be tested. Therefore, the battery 9 to be tested can obtain an excitation current similar to that flowing through the resistor R97 and the resistor R107 from both ends of the output lines ACRo+ and ACRo-; in order to avoid the impact on the current source when the high-voltage battery is connected, a resistor R134 for current limiting is added to suppress the surge current; the resistor R134 is switched by the conversion relay K4 and is short-circuited when outputting current.

[0074] One end of the resistor R101 is connected to the signal source module 2, and the other end is connected to the resistor R91 and the pin 3 of the operational amplifier U23A; the pin 1 of the operational amplifier U23A is connected to the resistor R96, the resistor R119 and the pin 3 of the switching relay K4, and the pin 2 is connected to the resistor R106 and the resistor R119;

[0075] Pin 1 of the switching relay K4 is connected to the resistor R146, the output end of the diode D13, the resistor R153 and the capacitor C135, pin 4 is connected to the resistor R99, pin 5 is connected to the resistor R134, pin 6 is connected to the resistor R134, pin 8 is connected to the input end of the diode D13, the output end of the light emitting diode LED4 and the collector of the transistor Q4; the base of the transistor Q4 is connected to the resistor R154 and the resistor R155, and the emitter is connected to the resistor R155; the resistor R153 is connected to the input end of the light emitting diode LED4;

[0076] Pin 5 of the operational amplifier U20B is connected to resistor R95 and resistor R79, pin 6 is connected to resistor R99 and resistor R112, and pin 7 is connected to resistor R112, resistor R97, resistor R107 and pin 3 of clamping diode D10; pin 1 of the operational amplifier U20A is connected to resistor R75, resistor R79 and pin 2 of the operational amplifier U20A, and pin 3 is connected to resistor R78 and pin 3 of clamping diode D9; the resistor R103 is respectively connected to resistor R78, resistor R97, resistor R107 and capacitor C106.

[0077] The ADC module 4 includes a voltage input unit 41, an internal resistance input unit 42, a signal input unit 43 and an analog-to-digital conversion unit 44;

[0078] One end of the voltage input unit 41 is connected to the voltage sampling module 6, and the other end is connected to the analog-to-digital conversion unit 44; one end of the internal resistance input unit 42 is connected to the filtering and amplifying module 7, and the other end is connected to the analog-to-digital conversion unit 44; one end of the signal input unit 43 is connected to the signal source module 2, and the other end is connected to the analog-to-digital conversion unit 44; the analog-to-digital conversion unit 44 is connected to the main control module 1.

[0079] The output signal of the filtering and amplifying module 7, the output signal of the voltage sampling module 6, and the reference signal of the digital orthogonal phase-locked are sent to the analog-to-digital conversion chip U16 through the operational amplifier U15, operational amplifier U22, and operational amplifier U25; the analog-to-digital conversion chip U16 uses a Σ-Δ type ADC, and the reference clock of the chip does not need to be synchronized with the communication clock. Its DRDY pin generates a square wave pulse according to the configured sampling rate and sends it to the IO port of the main control module 1. At the same time, the main control module 1 enters an interrupt through the external level jump on the pin, and reads the conversion data of the analog-to-digital conversion chip U16.

[0080] The voltage input unit 41 includes an operational amplifier U15, a resistor R67, a resistor R68, a resistor R73, a resistor R74, a resistor R81, a resistor R82, a resistor R84, a capacitor C100 and a clamping diode D11;

[0081] Pin 1 of the operational amplifier U15 is connected to resistor R74 and resistor R82, pin 4 is connected to resistor R82 and resistor R81, pin 5 is connected to resistor R67 and resistor R68, pin 7 is connected to resistor R84, and pin 8 is connected to resistor R68, resistor R73 and pin 3 of clamping diode D11; the resistor R73 and resistor R74 are respectively connected to voltage sampling module 6; one end of the capacitor C100 is connected to resistor R67 and analog-to-digital conversion unit 44, and the other end is connected to resistor R81 and analog-to-digital conversion unit 44;

[0082] The internal resistance input unit 42 includes an operational amplifier U22, a resistor R92, a resistor R93, a resistor R102, a resistor R108, a resistor R115, a resistor R117, a resistor R120, a capacitor C111 and a clamping diode D12;

[0083] Pin 1 of the operational amplifier U22 is connected to resistor R108 and resistor R115, pin 4 is connected to resistor R115 and resistor R117, pin 5 is connected to resistor R92 and resistor R93, pin 7 is connected to resistor R120, and pin 8 is connected to resistor R93, resistor R102, and pin 3 of clamping diode D12; the resistor R102 and resistor R108 are respectively connected to the filter amplifier module 7; one end of the capacitor C111 is connected to resistor R92 and analog-to-digital conversion unit 44, and the other end is connected to resistor R117 and analog-to-digital conversion unit 44;

[0084] The signal input unit 43 includes an operational amplifier U25, a resistor R127, a resistor R128, a resistor R129, a resistor R135, a resistor R136, a resistor R138, a resistor R139, a capacitor C121 and a clamping diode D14;

[0085] Pin 1 of the operational amplifier U15 is connected to resistor R74 and resistor R82, pin 4 is connected to resistor R82 and resistor R81, pin 5 is connected to resistor R67 and resistor R68, pin 7 is connected to resistor R84, and pin 8 is connected to resistor R68, resistor R73 and pin 3 of clamping diode D11; the resistor R73 and resistor R74 are respectively connected to the voltage sampling module 6; one end of the capacitor C100 is connected to resistor R67 and the analog-to-digital conversion unit 44, and the other end is connected to resistor R81 and the analog-to-digital conversion unit 44.

[0086] The analog-to-digital conversion unit 44 includes an analog-to-digital conversion chip U16, a resistor R69, a resistor R70, a resistor R83, a resistor R85, a resistor R86, a resistor R89, a resistor R111, a capacitor C99, a capacitor C103, a capacitor C107, a capacitor C108, a capacitor C109, a capacitor C110, a capacitor C117, a resistor group R76, a resistor group R77 and a resistor group R87;

[0087] Pins 1 and 2 of the analog-to-digital conversion chip U16 are connected to the voltage input unit 41, pins 3 and 4 are connected to the internal resistance input unit 42, pins 5 and 6 are connected to the signal input unit 43, pin 7 is connected to the resistor R86, pin 8 is connected to the resistor R89, pin 9 is connected to the capacitor C109 and the capacitor C110, pin 12 is connected to one end of the capacitor C107, pin 13 is connected to the other end of the capacitor C107, pin 14 is connected to the resistor R111 and the capacitor C117, pins 15 and 16 are connected to the capacitor C108, pins 17, 18, and 19 are connected to the resistor group R87, pins 20, 21, 22, and 23 are connected to the resistor group R76, pin 27 is connected to one end of the capacitor C99 and grounded, pin 28 is connected to the other end of the capacitor C99, pin 29 is connected to the resistor R70, the capacitor C98, and the main control module 1, pin 30 is connected to the resistor R70, and pin 31 is connected to the resistor R69;

[0088] The resistor group R87 is connected to the capacitor C103 , the resistor R85 and the main control module 1 ; one end of the resistor group R77 is connected to the resistor group R76 , and the other end is connected to the resistor R83 and the main control module 1 .

[0089] The over-range state detection module 5 includes a voltage detection unit 51 and an internal resistance detection unit 52; one end of the voltage detection unit 51 is connected to the voltage sampling module 6, and the other end is connected to the main control module 1; one end of the internal resistance detection unit 52 is connected to the filter amplification module 7, and the other end is connected to the main control module 1;

[0090] The input signals of the over-range state detection module 5 are ACIR_OL_DET_IN and VM_OL_DET_IN; the sampling signal of the voltage detection unit 51 is a relatively stable DC quantity, and only an ordinary hysteresis comparison circuit is needed to determine whether the signal exceeds the gear position; the internal resistance detection unit 52 is composed of a dual-path hysteresis comparator and a pulse detection circuit, and its input is an AC signal. When its amplitude exceeds the comparison threshold, the level of the comparator jumps near the threshold, which is not easy for the main control module 1 to detect, so a peak detection circuit and an inverter are used to convert it into a stable level.

[0091] The voltage detection unit 51 includes a comparator chip U35A, a diode D31, a resistor R110, a resistor R228, a resistor R231, a resistor R238, a resistor R239, a resistor R242, a resistor R243 and a resistor R246;

[0092] Pins 1 and 7 of the comparator chip U35A are connected to resistors R238, R110 and R239, pins 2 and 5 are connected to the voltage sampling module 6, pin 3 is connected to resistors R238, R231 and R243, and pin 6 is connected to resistors R239, R242 and R246; one end of the resistor R228 is connected to the main control module 1, and the other end is connected to the resistor R110 and the output end of the diode D31; the input ends of the resistor R243, the resistor R246 and the diode D31 are all grounded;

[0093] The internal resistance detection unit 52 includes a comparator chip U34A, an inverter chip U31, an inverter chip U32, a diode D16, a diode D25, a resistor R109, a resistor R181, a resistor R186, a resistor R187, a resistor R191, a resistor R195, a resistor R199, a resistor R212, a resistor R216 and a capacitor C164;

[0094] Pins 1 and 7 of the comparator chip U34A are connected to resistors R191, R109 and R195, pins 2 and 5 are connected to the filter amplifier module 7, pin 3 is connected to resistors R186 and R212, and pin 6 is connected to resistors R195, R199 and R216; one end of the resistor R181 is connected to the main control module 1, and the other end is connected to the resistor R109, the output end of the diode D25 and the pin 2 of the inverter chip U31. ; Pin 4 of the inverter chip U31 is connected to the input end of the diode D16, and pin 5 is connected to the main control module 1; Pin 2 of the inverter chip U32 is connected to the resistor R187, the capacitor C164 and the output end of the diode D16, and pin 4 is connected to the main control module 1; the resistor R212, the resistor R216, the input end of the diode D25, pin 3 of the inverter chip U31, the capacitor C164, the resistor R187 and pin 3 of the inverter chip U32 are all grounded.

[0095] The voltage sampling module 6 includes a resistor R3, a resistor R6, a resistor R8, a resistor R9, a resistor R10, a resistor R11, a resistor R12, a resistor R16, a resistor R17, a resistor R19, a resistor R20, a resistor R21, a resistor R22, a resistor R23, a resistor R24, a resistor R29, a resistor R31, a resistor R32, a resistor R33, a resistor R34, a resistor R35, a resistor R38, a resistor R39, a resistor R40, a resistor R41, a resistor R42, a resistor R43, a resistor R44, a resistor R45, a resistor R46, a resistor R50, a resistor R51, a resistor R52, a resistor R53, a resistor R54, a resistor R55, a resistor R56, a resistor R57, a resistor R58, a resistor R59, a resistor R60, a resistor R61, a resistor R62, a resistor R63, a resistor R64, a resistor R65, a resistor R66, a resistor R67, a resistor R68, a resistor R69, a resistor R70, a resistor R71, a resistor R72, a resistor R73, a resistor R74, a resistor R75 Resistor R56, a resistor R57, a resistor R58, a resistor R130, a capacitor C31, a capacitor C32, a capacitor C37, a capacitor C53, a capacitor C59, a capacitor C61, a capacitor C64, a capacitor C66, a capacitor C70, a capacitor C71, a capacitor C82, a capacitor C83, a clamping diode D1, a clamping diode D2, a clamping diode D4, an operational amplifier U3A, an operational amplifier U4, an operational amplifier U12A, a linear optocoupler U9, a light emitting diode LED2, a light emitting diode LED3, a diode D5, a diode D6, a transistor Q2, a transistor Q3, a switching relay K1, a switching relay K2, an AND gate chip U5, and an AND gate chip U8;

[0096] The voltage across the battery 9 to be tested is sent to the resistor attenuation network and the operational amplifier U4 via the signal line, output to the sampling side via the linear optocoupler U9 and the operational amplifier U12A, and sent to the ADC module 4 as differential signals VM+ and VM-; the conversion relay K1 and the conversion relay K2 switch the voltage attenuation ratio to select the appropriate gear; the combinational logic circuit composed of the AND gate chip U5 and the AND gate chip U8 controls the conversion relay K1 and the conversion relay K2 to select only one at the same time, which can save a signal channel.

[0097] One end of the resistor R9 is connected to the resistor R8, and the other end is connected to the resistor R10; one end of the resistor R11 is connected to the resistor R10, and the other end is connected to the resistor R12; pin 2 of the operational amplifier U4 is connected to the resistor R6, the capacitor C53, the resistor R24 ​​and the clamping diode D2, pin 3 is connected to the resistor R3, the resistor R12, the capacitor C32 and the clamping diode D1, and pin 6 is connected to the resistor R16, the resistor R6, the capacitor C53 and the resistor R38; one end of the resistor R21 is connected to the resistor R20, and the other end is connected to the resistor R22; one end of the resistor R23 is connected to the resistor R22, and the other end is connected to the resistor R24;

[0098] Pin 1 of the operational amplifier U3A is connected to resistor R39 and capacitor C64, pin 2 is connected to resistor R42, capacitor C64 and pin 4 of linear optocoupler U9, and pin 3 is connected to resistor R38; pin 2 of the linear optocoupler U9 is connected to resistor R39, pin 3 is connected to capacitor C66, pin 5 is connected to resistor R50, capacitor C70 and resistor R44, and pin 6 is connected to capacitor C59; resistor R50 is connected to capacitor C70 and grounded;

[0099] Pin 1 of the operational amplifier U12A is connected to resistor R46, resistor R43 and resistor R130, pin 2 is connected to resistor R35 and capacitor C61, and pin 3 is connected to resistor R45 and capacitor C71; the resistor R45 is connected to resistor R44 and capacitor C61; one end of the resistor R56 is connected to resistor R46 and grounded, and the other end is connected to ADC module 4; the resistor R43 is connected to clamping diode D4 and ADC module 4; the resistor R130 is connected to over-range state detection module 5;

[0100] Pin 1 of the switching relay K1 is connected to the resistor R40, the output end of the diode D5, the resistor R53 and the capacitor C82, pin 3 is connected to the resistor R31, pin 4 is connected to the resistor R11 and the resistor R12, pin 5 is connected to the resistor R23 and the resistor R24, pin 6 is connected to the resistor R32, pin 8 is connected to the input end of the diode D5, the output end of the light emitting diode LED2 and the collector of the transistor Q2; the resistor R53 is connected to the input end of the light emitting diode LED2; one end of the resistor R57 is connected to the resistor R51 and the base of the transistor Q2, and the other end is connected to the emitter of the transistor Q2;

[0101] Pin 1 of the switching relay K2 is connected to the output end of the resistor R41, the resistor R54, the capacitor C83 and the diode D6, pin 3 is connected to the resistor R33, pin 6 is connected to the resistor R34, pin 8 is connected to the input end of the diode D6, the output end of the light emitting diode LED3 and the collector of the transistor Q3; the resistor R54 is connected to the input end of the light emitting diode LED3; one end of the resistor R58 is connected to the resistor R52 and the base of the transistor Q3, and the other end is connected to the emitter of the transistor Q3;

[0102] Pin 1 of the AND gate chip U5 is connected to resistor R52, pin 2 is connected to resistor R17, pin 4 is connected to resistor R19, and pin 5 is connected to capacitor C31; pin 1 of the AND gate chip U8 is connected to resistor R19, pin 2 is connected to resistor R29, pin 4 is connected to resistor R51, and pin 5 is connected to capacitor C37.

[0103] The filtering and amplifying module 7 includes a resistor R14, a resistor R25, a resistor R163, a resistor R202, a resistor R234, a resistor R240, a resistor R241, a resistor R244, a resistor R245, a resistor R255, a resistor R260, a resistor R270, a capacitor C68, a capacitor C190, a capacitor C197, a capacitor C199, a capacitor C200, an operational amplifier U39A, an operational amplifier U39B, an operational amplifier U44A and an operational amplifier U44B;

[0104] The signal INBUF_OUT output by the internal resistance sampling module 8 passes through a narrow bandpass filter composed of a second-order Butterworth low-pass circuit and a second-order Butterworth high-pass circuit to filter out noise interference and residual DC components, obtain an AC signal RG_Select_in with a certain amplitude, and send it to the over-range state detection module 5 for further gear selection.

[0105] Pin 6 of the operational amplifier U39B is connected to resistor R25, resistor R163 and capacitor C68, and pin 7 is connected to resistor R14, resistor R163, ADC module 4 and over-range state detection module 5; pin 1 of the operational amplifier U39A is connected to resistor R25, resistor R202 and resistor R270, and pin 2 is connected to resistor R255 and resistor R270; pins 1 and 2 of the operational amplifier U44A are both connected to resistor R255, resistor R241 and resistor R260, and pin 3 is connected to resistor R234 and capacitor C199;

[0106] One end of the capacitor C197 is connected to the capacitor C199 and the resistor R260, and the other end is connected to the capacitor C190, the resistor R240 and the pins 6 and 7 of the operational amplifier U44B; the pin 5 of the operational amplifier U44B is connected to the capacitor C200 and the resistor R244; one end of the resistor R245 is connected to the resistor R244 and the capacitor C190, and the other end is connected to the internal resistance sampling module 8.

[0107] The internal resistance sampling module 8 includes an operational amplifier U37A, an operational amplifier U37B, an operational amplifier U38, a resistor R223, a resistor R224, a resistor R225, a resistor R226, a resistor R227, a resistor R236, a resistor R237, a resistor R247, a resistor R261, a resistor R262, a resistor R263, a resistor R269, a capacitor C187, a capacitor C189, a capacitor C191, a capacitor C198, a capacitor C207, a high-frequency magnetic bead L14, a high-frequency magnetic bead L16, a transient suppression diode D20, a transient suppression diode D24, a clamping diode D21, a clamping diode D22, a common-mode inductor L15 and a fuse F1;

[0108] The function of the internal resistance sampling module 8 is to convert the differential signal at both ends of the sampling input line ACRi+ and ACRi- into a single-ended signal INBUF_OUT after certain processing; the sampling input line signal is filtered out of common mode noise through the common mode inductor L15, and the differential signal is obtained from both ends of the battery to be tested 9 through the operational amplifier U37A, operational amplifier U3B and capacitor C187, capacitor C207, and the DC component is initially filtered out, and sent to the operational amplifier U38 to be converted into a single-ended signal; the transient suppression diode D20 and the transient suppression diode D24 are used for electrostatic protection on the input line side; the clamp The clamping diode D21 and the clamping diode D22 are used to prevent the overvoltage at the input end from damaging the operational amplifier chip; the operational amplifier U38 uses a precision instrument amplifier, and its peripheral circuit includes the high-frequency magnetic beads L14 and L16 to suppress radio frequency noise interference; the common-mode filter circuit includes the resistor R227, the resistor R237, the capacitor C189, the capacitor C198, and the capacitor C191; the gain resistor network is connected to Rg+ and Rg-, and the gain resistors of different sizes are selected by the relay, and the amplification factor is selected by the control signal of the main control module 1 to control the gear switching.

[0109] Pin 1 of the operational amplifier U38 is connected to the resistor R227, the capacitor C189 and the capacitor C191, pin 4 is connected to the resistor R237, the capacitor C191 and the capacitor C198, pin 6 is connected to the resistor R236 and grounded, and pin 7 is connected to the resistor R236 and the filter amplifier module 7;

[0110] One end of the high-frequency magnetic bead L14 is connected to the resistor R227, and the other end is connected to the resistor R223, the resistor R226 and the pin 7 of the operational amplifier U37B; the pin 5 of the operational amplifier U37B is connected to the resistor R224 and the transient suppression diode D20, and the pin 6 is connected to the resistor R226; one end of the resistor R225 is connected to the resistor R224 and the pin 3 of the clamping diode D21, and the other end is connected to the resistor R222 and the capacitor C187;

[0111] One end of the high-frequency magnetic bead L16 is connected to the resistor R237, and the other end is connected to the resistor R247, the resistor R263 and the pin 1 of the operational amplifier U37A; the pin 3 of the operational amplifier U37A is connected to the resistor R261 and the transient suppression diode D24, and the pin 2 is connected to the resistor R247; one end of the resistor R262 is connected to the resistor R261 and the pin 3 of the clamping diode D22, and the other end is connected to the resistor R269 and the capacitor C207;

[0112] Pin 1 of the common mode inductor L15 is connected to the capacitor C207 , pin 2 is connected to the fuse F1 , and pin 4 is connected to the capacitor C187 .

[0113] The battery to be tested 9 is connected to ACRo+ and ACRo− of the AC constant current source module 3 , connected to VH+ and VH− of the voltage sampling module 6 , and connected to ACRi+ and ACRi− of the internal resistance sampling module 8 .

[0114] Working principle of the present invention:

[0115] The battery 9 to be tested is connected, and the main control module 1 controls the signal source module 2 to generate a 1KHz sinusoidal waveform and input it into the AC constant current source module 3, and the battery 9 to be tested is pre-charged through the AC constant current source module 3; after a certain delay, the current is loaded on the battery 9 to be tested through the AC constant current source module 3, and the voltage and AC internal resistance are sampled through the voltage sampling module 6 and the internal resistance sampling module 8; the sampling signal of the voltage sampling module 6 is directly input into the ADC module 4 and the over-range state detection module 5; the sampling signal of the internal resistance sampling module 8 is input into the ADC module 4 and the over-range state detection module 5 through the filtering and amplifying module 7.

[0116] The over-range state detection module 5 adjusts the gears of the voltage sampling module 6 and the filtering and amplifying module 7 based on the received sampling signal; the ADC module 4 performs analog-to-digital conversion on the sampling signal and inputs it into the main control module 1, and the main control module 1 obtains the voltage, impedance modulus, impedance angle and accurate frequency through orthogonal phase-locked operation.

[0117] In summary, the advantages of the present invention are:

[0118] 1. Only one main control module 1 (a single-chip microcomputer with DSP function) is used to set the current reference waveform output by the signal source module 2 and use it for orthogonal phase-locked calculation. A high-resolution ADC module 4 is used to ensure the synchronization of the sampling data. A voltage sampling module 6 and a filter amplifier module 7 are set to perform multi-level sampling of the AC internal resistance and voltage of the battery 9 to be tested. Under the premise of ensuring the detection accuracy, the circuit cost is greatly reduced, and finally the lithium battery detection speed is greatly improved and the lithium battery detection cost is greatly reduced.

[0119] 2. By setting the main control module 1 for process step control and complex digital calculations in the internal resistance measurement process, it not only provides an efficient, high-precision, and low-cost measurement method for the AC internal resistance test in the lithium battery test, but also can collect the voltage of the battery cell / battery pack in grades, which is convenient for integration with the industrial test system, and can accurately obtain the open circuit voltage, AC internal resistance, and impedance angle of the battery 9 to be tested.

[0120] Although the specific implementation modes of the present invention are described above, those skilled in the art should understand that the specific implementation modes described are only illustrative and are not intended to limit the scope of the present invention. Equivalent modifications and changes made by those skilled in the art in accordance with the spirit of the present invention should be included in the scope of protection of the claims of the present invention.

Claims

1. A lithium battery voltage and internal resistance detection circuit based on digital orthogonal phase-locked technology, Features: It includes a main control module, a signal source module, an AC constant current source module, an ADC module, an over-range state detection module, a voltage sampling module, a filter amplification module and an internal resistance sampling module; The input end of the signal source module is connected to the main control module, and the output end is connected to the AC constant current source module and the ADC module; the input end of the over-range state detection module is connected to the voltage sampling module and the filter amplification module, and the output end is connected to the main control module; the output end of the internal resistance sampling module is connected to the filter amplification module; the input end of the ADC module is connected to the signal source module, the voltage sampling module and the filter amplification module, and the output end is connected to the main control module; The over-range state detection module includes a voltage detection unit and an internal resistance detection unit; one end of the voltage detection unit is connected to the voltage sampling module, and the other end is connected to the main control module; one end of the internal resistance detection unit is connected to the filter amplification module, and the other end is connected to the main control module; The voltage detection unit includes a comparator chip U35A, a diode D31, a resistor R110, a resistor R228, a resistor R231, a resistor R238, a resistor R239, a resistor R242, a resistor R243 and a resistor R246; Pins 1 and 7 of the comparator chip U35A are connected to resistors R238, R110 and R239, pins 2 and 5 are connected to the voltage sampling module, pin 3 is connected to resistors R238, R231 and R243, and pin 6 is connected to resistors R239, R242 and R246; one end of the resistor R228 is connected to the main control module, and the other end is connected to the resistor R110 and the output end of the diode D31; the input ends of the resistor R243, the resistor R246 and the diode D31 are all grounded; The internal resistance detection unit includes a comparator chip U34A, an inverter chip U31, an inverter chip U32, a diode D16, a diode D25, a resistor R109, a resistor R181, a resistor R186, a resistor R187, a resistor R191, a resistor R195, a resistor R199, a resistor R212, a resistor R216 and a capacitor C164; Pins 1 and 7 of the comparator chip U34A are connected to resistors R191, R109 and R195, pins 2 and 5 are connected to the filter amplifier module, pin 3 is connected to resistors R186 and R212, and pin 6 is connected to resistors R195, R199 and R216; one end of the resistor R181 is connected to the main control module, and the other end is connected to the resistor R109, the output end of the diode D25 and pin 2 of the inverter chip U31. ; Pin 4 of the inverter chip U31 is connected to the input end of the diode D16, and pin 5 is connected to the main control module; Pin 2 of the inverter chip U32 is connected to the output end of the resistor R187, the capacitor C164 and the diode D16, and pin 4 is connected to the main control module; the resistor R212, the resistor R216, the input end of the diode D25, pin 3 of the inverter chip U31, the capacitor C164, the resistor R187 and pin 3 of the inverter chip U32 are all grounded.

2. A lithium battery voltage and internal resistance detection circuit based on digital orthogonal phase-locked technology as claimed in claim 1, Features: The signal source module includes an operational amplifier U17A, an operational amplifier U17B, an operational amplifier U18A, an operational amplifier U18B, an operational amplifier U21A, an operational amplifier U23B, a resistor R88, a resistor R90, a resistor R94, a resistor R98, a resistor R100, a resistor R104, a resistor R105, a resistor R113, a resistor R118, a resistor R126, a resistor R131, a resistor R132, a resistor R133, a resistor R151, and a resistor R157. A resistor R152, a resistor R169, a resistor R176, a resistor R177, a resistor R179, a resistor R180, a resistor R298, a resistor R301, a resistor R302, a capacitor C102, a capacitor C104, a capacitor C112, a capacitor C114, a capacitor C115, a capacitor C116, a capacitor C118, a capacitor C157, a capacitor C158, a capacitor C159, a capacitor C169 and a linear optocoupler U19; One end of the resistor R90 is connected to the resistor R131 and the main control module, and the other end is connected to the pin 3 of the operational amplifier U17A; the pin 1 of the operational amplifier U17A is connected to the capacitor C114 and the resistor R94, and the pin 2 is connected to the resistor R100, the capacitor C114 and the pin 4 of the linear optocoupler U19; the pin 2 of the linear optocoupler U19 is connected to the resistor R94, the pin 3 is connected to the capacitor C112, the pin 5 is connected to the resistor R104 and the resistor R113, and the pin 6 is connected to the capacitor C104; Pin 1 of the operational amplifier U21A is connected to capacitor C115, resistor R88, capacitor C102 and pin 2 of the operational amplifier U21A, and pin 3 is connected to resistor R105 and capacitor C118; the resistor R105 is connected to resistor R104 and capacitor C102; pin 5 of the operational amplifier U23B is connected to resistor R118 and capacitor C116, and pin 6 is connected to resistor R126, resistor R98, an AC constant current source module and pin 7 of the operational amplifier U23B; the capacitor C116 is connected to capacitor C115 and resistor R98.

3. A lithium battery voltage and internal resistance detection circuit based on digital orthogonal phase-locked technology as claimed in claim 1, Features: The AC constant current source module includes a resistor R75, a resistor R78, a resistor R79, a resistor R91, a resistor R95, a resistor R96, a resistor R97, a resistor R99, a resistor R101, a resistor R103, a resistor R106, a resistor R107, a resistor R112, a resistor R119, a resistor R134, a resistor R146, a resistor R153, a resistor R154, a resistor R155, a capacitor C106, a capacitor C135, an operational amplifier U20A, an operational amplifier U20B, an operational amplifier U23A, a light emitting diode LED4, a diode D13, a transistor Q4, a conversion relay K4, a clamping diode D9 and a clamping diode D10; One end of the resistor R101 is connected to the signal source module, and the other end is connected to the resistor R91 and the pin 3 of the operational amplifier U23A; the pin 1 of the operational amplifier U23A is connected to the resistor R96, the resistor R119 and the pin 3 of the switching relay K4, and the pin 2 is connected to the resistor R106 and the resistor R119; Pin 1 of the switching relay K4 is connected to the resistor R146, the output end of the diode D13, the resistor R153 and the capacitor C135, pin 4 is connected to the resistor R99, pin 5 is connected to the resistor R134, pin 6 is connected to the resistor R134, pin 8 is connected to the input end of the diode D13, the output end of the light emitting diode LED4 and the collector of the transistor Q4; the base of the transistor Q4 is connected to the resistor R154 and the resistor R155, and the emitter is connected to the resistor R155; the resistor R153 is connected to the input end of the light emitting diode LED4; Pin 5 of the operational amplifier U20B is connected to resistor R95 and resistor R79, pin 6 is connected to resistor R99 and resistor R112, and pin 7 is connected to resistor R112, resistor R97, resistor R107 and pin 3 of clamping diode D10; pin 1 of the operational amplifier U20A is connected to resistor R75, resistor R79 and pin 2 of the operational amplifier U20A, and pin 3 is connected to resistor R78 and pin 3 of clamping diode D9; the resistor R103 is respectively connected to resistor R78, resistor R97, resistor R107 and capacitor C106.

4. A lithium battery voltage and internal resistance detection circuit based on digital orthogonal phase-locked technology as claimed in claim 1, Features: The ADC module includes a voltage input unit, an internal resistance input unit, a signal input unit and an analog-to-digital conversion unit; One end of the voltage input unit is connected to the voltage sampling module, and the other end is connected to the analog-to-digital conversion unit; one end of the internal resistance input unit is connected to the filtering and amplifying module, and the other end is connected to the analog-to-digital conversion unit; one end of the signal input unit is connected to the signal source module, and the other end is connected to the analog-to-digital conversion unit; the analog-to-digital conversion unit is connected to the main control module.

5. A lithium battery voltage and internal resistance detection circuit based on digital orthogonal phase-locked technology as claimed in claim 4, Features: The voltage input unit includes an operational amplifier U15, a resistor R67, a resistor R68, a resistor R73, a resistor R74, a resistor R81, a resistor R82, a resistor R84, a capacitor C100 and a clamping diode D11; Pin 1 of the operational amplifier U15 is connected to resistor R74 and resistor R82, pin 4 is connected to resistor R82 and resistor R81, pin 5 is connected to resistor R67 and resistor R68, pin 7 is connected to resistor R84, and pin 8 is connected to resistor R68, resistor R73 and pin 3 of clamping diode D11; the resistor R73 and resistor R74 are respectively connected to the voltage sampling module; one end of the capacitor C100 is connected to resistor R67 and the analog-to-digital conversion unit, and the other end is connected to resistor R81 and the analog-to-digital conversion unit; The internal resistance input unit includes an operational amplifier U22, a resistor R92, a resistor R93, a resistor R102, a resistor R108, a resistor R115, a resistor R117, a resistor R120, a capacitor C111 and a clamping diode D12; Pin 1 of the operational amplifier U22 is connected to resistor R108 and resistor R115, pin 4 is connected to resistor R115 and resistor R117, pin 5 is connected to resistor R92 and resistor R93, pin 7 is connected to resistor R120, and pin 8 is connected to resistor R93, resistor R102, and pin 3 of clamping diode D12; the resistor R102 and resistor R108 are respectively connected to the filter amplification module; one end of the capacitor C111 is connected to resistor R92 and the analog-to-digital conversion unit, and the other end is connected to resistor R117 and the analog-to-digital conversion unit; The signal input unit includes an operational amplifier U25, a resistor R127, a resistor R128, a resistor R129, a resistor R135, a resistor R136, a resistor R138, a resistor R139, a capacitor C121 and a clamping diode D14.

6. A lithium battery voltage and internal resistance detection circuit based on digital orthogonal phase-locked technology as claimed in claim 4, Features: The analog-to-digital conversion unit includes an analog-to-digital conversion chip U16, a resistor R69, a resistor R70, a resistor R83, a resistor R85, a resistor R86, a resistor R89, a resistor R111, a capacitor C99, a capacitor C103, a capacitor C107, a capacitor C108, a capacitor C109, a capacitor C110, a capacitor C117, a resistor group R76, a resistor group R77 and a resistor group R87; Pins 1 and 2 of the analog-to-digital conversion chip U16 are connected to the voltage input unit, pins 3 and 4 are connected to the internal resistance input unit, pins 5 and 6 are connected to the signal input unit, pin 7 is connected to the resistor R86, pin 8 is connected to the resistor R89, pin 9 is connected to the capacitor C109 and the capacitor C110, pin 12 is connected to one end of the capacitor C107, pin 13 is connected to the other end of the capacitor C107, pin 14 is connected to the resistor R111 and the capacitor C117, pins 15 and 16 are connected to the capacitor C108, pins 17, 18, and 19 are connected to the resistor group R87, pins 20, 21, 22, and 23 are connected to the resistor group R76, pin 27 is connected to one end of the capacitor C99 and grounded, pin 28 is connected to the other end of the capacitor C99, pin 29 is connected to the resistor R70, the capacitor C98, and the main control module, pin 30 is connected to the resistor R70, and pin 31 is connected to the resistor R69; The resistor group R87 is connected to the capacitor C103, the resistor R85 and the main control module; one end of the resistor group R77 is connected to the resistor group R76, and the other end is connected to the resistor R83 and the main control module.

7. A lithium battery voltage and internal resistance detection circuit based on digital orthogonal phase-locked technology as claimed in claim 1, Features: The voltage sampling module includes a resistor R3, a resistor R6, a resistor R8, a resistor R9, a resistor R10, a resistor R11, a resistor R12, a resistor R16, a resistor R17, a resistor R19, a resistor R20, a resistor R21, a resistor R22, a resistor R23, a resistor R24, a resistor R29, a resistor R31, a resistor R32, a resistor R33, a resistor R34, a resistor R35, a resistor R38, a resistor R39, a resistor R40, a resistor R41, a resistor R42, a resistor R43, a resistor R44, a resistor R45, a resistor R46, a resistor R50, a resistor R51, a resistor R52, a resistor R53, a resistor R54, a resistor R55, a resistor R56, a resistor R57, a resistor R58, a resistor R59, a resistor R60, a resistor R61, a resistor R62, a resistor R63, a resistor R64, a resistor R65, a resistor R66, a resistor R67, a resistor R68, a resistor R69, a resistor R70, a resistor R71, a resistor R72, a resistor R73, a resistor R74, a resistor R75 Resistor R56, a resistor R57, a resistor R58, a resistor R130, a capacitor C31, a capacitor C32, a capacitor C37, a capacitor C53, a capacitor C59, a capacitor C61, a capacitor C64, a capacitor C66, a capacitor C70, a capacitor C71, a capacitor C82, a capacitor C83, a clamping diode D1, a clamping diode D2, a clamping diode D4, an operational amplifier U3A, an operational amplifier U4, an operational amplifier U12A, a linear optocoupler U9, a light emitting diode LED2, a light emitting diode LED3, a diode D5, a diode D6, a transistor Q2, a transistor Q3, a switching relay K1, a switching relay K2, an AND gate chip U5, and an AND gate chip U8; One end of the resistor R9 is connected to the resistor R8, and the other end is connected to the resistor R10; one end of the resistor R11 is connected to the resistor R10, and the other end is connected to the resistor R12; pin 2 of the operational amplifier U4 is connected to the resistor R6, the capacitor C53, the resistor R24 ​​and the clamping diode D2, pin 3 is connected to the resistor R3, the resistor R12, the capacitor C32 and the clamping diode D1, and pin 6 is connected to the resistor R16, the resistor R6, the capacitor C53 and the resistor R38; one end of the resistor R21 is connected to the resistor R20, and the other end is connected to the resistor R22; one end of the resistor R23 is connected to the resistor R22, and the other end is connected to the resistor R24; Pin 1 of the operational amplifier U3A is connected to resistor R39 and capacitor C64, pin 2 is connected to resistor R42, capacitor C64 and pin 4 of linear optocoupler U9, and pin 3 is connected to resistor R38; pin 2 of the linear optocoupler U9 is connected to resistor R39, pin 3 is connected to capacitor C66, pin 5 is connected to resistor R50, capacitor C70 and resistor R44, and pin 6 is connected to capacitor C59; resistor R50 is connected to capacitor C70 and grounded; Pin 1 of the operational amplifier U12A is connected to resistor R46, resistor R43 and resistor R130, pin 2 is connected to resistor R35 and capacitor C61, and pin 3 is connected to resistor R45 and capacitor C71; the resistor R45 is connected to resistor R44 and capacitor C61; one end of the resistor R56 is connected to resistor R46 and grounded, and the other end is connected to the ADC module; the resistor R43 is connected to the clamping diode D4 and the ADC module; the resistor R130 is connected to the over-range state detection module; Pin 1 of the switching relay K1 is connected to the resistor R40, the output end of the diode D5, the resistor R53 and the capacitor C82, pin 3 is connected to the resistor R31, pin 4 is connected to the resistor R11 and the resistor R12, pin 5 is connected to the resistor R23 and the resistor R24, pin 6 is connected to the resistor R32, pin 8 is connected to the input end of the diode D5, the output end of the light emitting diode LED2 and the collector of the transistor Q2; the resistor R53 is connected to the input end of the light emitting diode LED2; one end of the resistor R57 is connected to the resistor R51 and the base of the transistor Q2, and the other end is connected to the emitter of the transistor Q2; Pin 1 of the switching relay K2 is connected to the output end of the resistor R41, the resistor R54, the capacitor C83 and the diode D6, pin 3 is connected to the resistor R33, pin 6 is connected to the resistor R34, pin 8 is connected to the input end of the diode D6, the output end of the light emitting diode LED3 and the collector of the transistor Q3; the resistor R54 is connected to the input end of the light emitting diode LED3; one end of the resistor R58 is connected to the resistor R52 and the base of the transistor Q3, and the other end is connected to the emitter of the transistor Q3; Pin 1 of the AND gate chip U5 is connected to resistor R52, pin 2 is connected to resistor R17, pin 4 is connected to resistor R19, and pin 5 is connected to capacitor C31; pin 1 of the AND gate chip U8 is connected to resistor R19, pin 2 is connected to resistor R29, pin 4 is connected to resistor R51, and pin 5 is connected to capacitor C37.

8. A lithium battery voltage and internal resistance detection circuit based on digital orthogonal phase-locked technology as claimed in claim 1, Features: The filtering and amplifying module includes a resistor R14, a resistor R25, a resistor R163, a resistor R202, a resistor R234, a resistor R240, a resistor R241, a resistor R244, a resistor R245, a resistor R255, a resistor R260, a resistor R270, a capacitor C68, a capacitor C190, a capacitor C197, a capacitor C199, a capacitor C200, an operational amplifier U39A, an operational amplifier U39B, an operational amplifier U44A and an operational amplifier U44B; Pin 6 of the operational amplifier U39B is connected to resistor R25, resistor R163 and capacitor C68, and pin 7 is connected to resistor R14, resistor R163, ADC module and over-range state detection module; pin 1 of the operational amplifier U39A is connected to resistor R25, resistor R202 and resistor R270, and pin 2 is connected to resistor R255 and resistor R270; pins 1 and 2 of the operational amplifier U44A are both connected to resistor R255, resistor R241 and resistor R260, and pin 3 is connected to resistor R234 and capacitor C199; One end of the capacitor C197 is connected to the capacitor C199 and the resistor R260, and the other end is connected to the capacitor C190, the resistor R240 and the pins 6 and 7 of the operational amplifier U44B; the pin 5 of the operational amplifier U44B is connected to the capacitor C200 and the resistor R244; one end of the resistor R245 is connected to the resistor R244 and the capacitor C190, and the other end is connected to the internal resistance sampling module.

9. A lithium battery voltage and internal resistance detection circuit based on digital orthogonal phase-locked technology as claimed in claim 1, Features: The internal resistance sampling module includes an operational amplifier U37A, an operational amplifier U37B, an operational amplifier U38, a resistor R223, a resistor R224, a resistor R225, a resistor R226, a resistor R227, a resistor R236, a resistor R237, a resistor R247, a resistor R261, a resistor R262, a resistor R263, a resistor R269, a capacitor C187, a capacitor C189, a capacitor C191, a capacitor C198, a capacitor C207, a high-frequency magnetic bead L14, a high-frequency magnetic bead L16, a transient suppression diode D20, a transient suppression diode D24, a clamping diode D21, a clamping diode D22, a common-mode inductor L15 and a fuse F1; Pin 1 of the operational amplifier U38 is connected to the resistor R227, the capacitor C189 and the capacitor C191, pin 4 is connected to the resistor R237, the capacitor C191 and the capacitor C198, pin 6 is connected to the resistor R236 and grounded, and pin 7 is connected to the resistor R236 and the filter amplifier module; One end of the high-frequency magnetic bead L14 is connected to the resistor R227, and the other end is connected to the resistor R223, the resistor R226 and the pin 7 of the operational amplifier U37B; the pin 5 of the operational amplifier U37B is connected to the resistor R224 and the transient suppression diode D20, and the pin 6 is connected to the resistor R226; one end of the resistor R225 is connected to the resistor R224 and the pin 3 of the clamping diode D21, and the other end is connected to the resistor R222 and the capacitor C187; One end of the high-frequency magnetic bead L16 is connected to the resistor R237, and the other end is connected to the resistor R247, the resistor R263 and the pin 1 of the operational amplifier U37A; the pin 3 of the operational amplifier U37A is connected to the resistor R261 and the transient suppression diode D24, and the pin 2 is connected to the resistor R247; one end of the resistor R262 is connected to the resistor R261 and the pin 3 of the clamping diode D22, and the other end is connected to the resistor R269 and the capacitor C207; Pin 1 of the common mode inductor L15 is connected to the capacitor C207 , pin 2 is connected to the fuse F1 , and pin 4 is connected to the capacitor C187 .

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