Voltage measurement circuit and voltage measurement method for new energy automobile battery

Abstract

The invention discloses a voltage measuring circuit and method for a new energy automobile battery, and the circuit comprises two voltage division circuits, two differential operational amplifier circuits, and an analog-to-digital conversion circuit. Wherein the first input end of one voltage division circuit and the second input end of the other voltage division circuit are simultaneously connected with one battery voltage input end of the battery connecting seat, and the second input end of one voltage division circuit and the first input end of the other voltage division circuit are simultaneously connected with the other battery voltage input end of the battery connecting seat; two voltage output ends of each voltage division circuit are respectively connected with a comparison signal input end of one differential operational amplifier circuit; the analog-to-digital conversion circuit comprises an analog-to-digital converter, and a first voltage transmission pin and a second voltage transmission pin of the analog-to-digital converter are respectively connected with comparison signal output ends of the two differential operational amplifier circuits. According to the voltage measurement circuit, the circuit arrangement structure is simplified, so that the cost is reduced, and the reliability of voltage measurement is improved.

Description

Technical Field

[0001] The present invention relates to the field of circuit technology, and in particular to a voltage measurement circuit and a voltage measurement method for a new energy vehicle battery. Background Art

[0002] As the main energy source of new energy vehicles, the safety and reliability of power batteries are very important. The acquisition of battery voltage can obtain an important battery monitoring parameter. The acquisition of each single cell voltage involves battery balanced power supply and battery safety monitoring. In the prior art, the acquisition of new energy battery voltage is to measure and collect the voltage in the battery pack through a sampling module (AFE, AnalogFront End). However, the sampling module is often complex in circuit and high in cost, and it is difficult to configure one by one for a large number of single cells contained in the power battery, that is, it cannot be widely used to measure the voltage of each single cell. Therefore, the prior art has the problem of not being able to measure the voltage of each single cell at a low cost. Summary of the invention

[0003] The embodiments of the present invention provide a voltage measurement circuit and a voltage measurement method for a new energy vehicle battery, aiming to solve the problem in the prior art that the voltage of each single battery cannot be measured at a low cost.

[0004] In a first aspect, an embodiment of the present invention discloses a voltage measurement circuit for a new energy vehicle battery, wherein the voltage measurement circuit includes two voltage divider circuits, two differential operational amplifier circuits and an analog-to-digital conversion circuit; The first input end of one of the voltage divider circuits and the second input end of the other voltage divider circuit are simultaneously connected to a battery voltage input end of a battery connection socket, and the second input end of one of the voltage divider circuits and the first input end of the other voltage divider circuit are simultaneously connected to another battery voltage input end of the battery connection socket; The two voltage output terminals of each voltage divider circuit are respectively connected to a comparison signal input terminal of the differential operational amplifier circuit; the analog-to-digital conversion circuit includes an analog-to-digital converter, and the first voltage transmission pin and the second voltage transmission pin of the analog-to-digital converter are respectively connected to the comparison signal output terminals of the two differential operational amplifier circuits; The voltage divider circuit includes a first resistor, a second resistor, a third resistor, a first TVS tube, a second TVS tube and a third TVS tube; one end of the first resistor serves as a first input end of the voltage divider circuit; the other end of the first resistor is connected to the positive electrode of the first TVS tube, the positive electrode of the second TVS tube and one end of the third resistor, and the connection point serves as a voltage output end of the voltage divider circuit; the other end of the third resistor is connected to the negative electrode of the second TVS tube, the positive electrode of the third TVS tube and one end of the second resistor, and the connection point serves as another voltage output end of the voltage divider circuit; the other end of the second resistor serves as a second input end of the voltage divider circuit; the negative electrode of the first TVS tube and the negative electrode of the third TVS tube are both grounded; The differential operational amplifier circuit includes an operational amplifier, a fourth resistor, a fifth resistor, a sixth resistor and a seventh resistor; one end of the fourth resistor serves as a comparison signal input end of the differential operational amplifier circuit, and the other end of the fourth resistor is connected to one end of the sixth resistor and the negative input end of the operational amplifier; one end of the fifth resistor serves as another comparison signal input end of the differential operational amplifier circuit, and the other end of the fifth resistor is connected to one end of the seventh resistor and the positive input end of the operational amplifier; the power supply end of the operational amplifier is connected to a low-voltage power supply, and the reference voltage input end of the operational amplifier is grounded; The other end of the sixth resistor is connected to the output end of the operational amplifier, and the connection point serves as the comparison signal output end of the differential operational amplifier circuit; the other end of the seventh resistor is grounded; the resistance value of the seventh resistor is equal to that of the sixth resistor, and the resistance value of the fifth resistor is equal to that of the fourth resistor.

[0005] In a second aspect, an embodiment of the present invention further discloses a voltage measurement method for a new energy vehicle battery, wherein the voltage measurement method is applied to a measurement terminal, and the measurement terminal is communicatively connected to an analog-to-digital converter in a voltage measurement circuit for a new energy vehicle battery as described in the first aspect above, and the voltage measurement method includes: If a digital signal is received from the analog-to-digital converter, a code rate value corresponding to the current sampling frequency is obtained according to a preset sampling configuration table; Convert the digital signal and the bit rate value according to a preset conversion formula to obtain a corresponding initial conversion voltage value; The initial conversion voltage is divided and calculated according to a preset voltage division calculation formula to obtain a corresponding voltage measurement value.

[0006] The embodiment of the present application discloses a voltage measurement circuit and a voltage measurement method for a new energy vehicle battery, wherein the voltage measurement circuit includes two voltage divider circuits, two differential operational amplifier circuits and an analog-to-digital conversion circuit, wherein the first input end of one voltage divider circuit and the second input end of another voltage divider circuit are simultaneously connected to a battery voltage input end of a battery connection seat, wherein the second input end of one voltage divider circuit and the first input end of another voltage divider circuit are simultaneously connected to another battery voltage input end of the battery connection seat; the two voltage output ends of each voltage divider circuit are respectively connected to a comparison signal input end of a differential operational amplifier circuit; the analog-to-digital conversion circuit includes an analog-to-digital converter, and the first voltage transmission pin and the second voltage transmission pin of the analog-to-digital converter are respectively connected to the comparison signal output ends of two differential operational amplifier circuits. The above-mentioned voltage measurement circuit reduces costs by simplifying the circuit setting structure; the use of a differential operational amplifier circuit can effectively improve the detection accuracy and realize high and low voltage isolation to avoid high voltage from damaging the subsequent circuit components, increase the reliability of voltage measurement, and has the application effect of low energy consumption and improved performance of the circuit system. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying any creative work.

[0008] Figure 1 A partial circuit structure diagram of a voltage measurement circuit provided by an embodiment of the present invention; Figure 2 Another partial circuit structure diagram of the voltage measurement circuit provided by an embodiment of the present invention; Figure 3 A method flow chart of a voltage measurement method provided by an embodiment of the present invention; Figure numerals: S1, differential operational amplifier circuit; S2, voltage divider circuit; S3, analog-to-digital conversion circuit; U17A, operational amplifier; U20, analog-to-digital converter; R137, first resistor; R144, second resistor; R140, third resistor; D38, first TVS tube; D13, second TVS tube; D39, third TVS tube; R139, fourth resistor; R142, fifth resistor; R136, sixth resistor; R146, seventh Resistor; C236, first capacitor; C235, second capacitor; R141, eighth resistor; C221, third capacitor; R143, ninth resistor; C198, fourth capacitor; FB5, first ferromagnetic bead; C200, fifth capacitor; C219, sixth capacitor; C227, seventh capacitor; C228, eighth capacitor; FB6, second ferromagnetic bead; R147, tenth resistor; R149, eleventh resistor; J4, battery connector. DETAILED DESCRIPTION

[0009] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0010] It should be understood that when used in this specification and the appended claims, the terms "include" and "comprises" indicate the presence of described features, integers, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or combinations thereof.

[0011] It should also be understood that the terms used in the present specification are only for the purpose of describing specific embodiments and are not intended to limit the present invention. As used in the present specification and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" are intended to include plural forms.

[0012] It should be further understood that the term "and / or" used in the present description and the appended claims refers to and includes any and all possible combinations of one or more of the associated listed items.

[0013] The embodiment of the present invention discloses a voltage measurement circuit for a new energy vehicle battery, such as Figure 1 and Figure 2 As shown, the voltage measurement circuit includes two voltage divider circuits S2, two differential operational amplifier circuits S1 and an analog-to-digital conversion circuit S3; the first input end of one of the voltage divider circuits S2 and the second input end of the other voltage divider circuit S2 are simultaneously connected to a battery voltage input end of the battery connection socket J4, and the second input end of one of the voltage divider circuits S2 and the first input end of the other voltage divider circuit S2 are simultaneously connected to another battery voltage input end of the battery connection socket J4; the two voltage output ends of each of the voltage divider circuits S2 are respectively connected to a comparison signal input end of the differential operational amplifier circuit S1; the analog-to-digital conversion circuit S3 includes an analog-to-digital converter U20, and the first voltage transmission pin and the second voltage transmission pin of the analog-to-digital converter U20 are respectively connected to the comparison signal output ends of the two differential operational amplifier circuits S1.

[0014] The voltage measurement circuit can be composed of two voltage divider circuits S2, two differential operational amplifier circuits S1 and an analog-to-digital conversion circuit S3. The input wiring directions of the two voltage divider circuits S2 are opposite, that is, the first input terminal and the second input terminal of one voltage divider circuit S2 are positively connected to the battery voltage input terminal of the battery connector J4, and the first input terminal and the second input terminal of the other voltage divider circuit S2 are reversely connected to the battery voltage input terminal of the battery connector J4. Therefore, whether the battery is positively connected to the battery connector J4 or reversely connected to the battery connector J4, the battery power measurement can be performed accordingly. For example, if the negative pole of the battery is connected to the PWR- pin of the battery connector J4, and the positive pole of the battery is connected to the PWR+ pin, then Figure 1 The voltage divider circuit S2 and the differential amplifier circuit S1 on the lower middle side work together to measure the voltage; if the negative pole of the battery is connected to the PWR+ pin of the battery connector J4, and the positive pole of the battery is connected to the PWR- pin, then Figure 1 The voltage divider circuit S2 and the differential op amp circuit S1 on the upper middle side work together to measure the voltage and have the function of preventing reverse connection. The analog-to-digital converter U20 can use the ADS1110A0IDBVR chip, which has the characteristics of low power consumption, continuous self-calibration, programmable conversion rate, programmable gain amplifier (PGA) and support for communication with MCU through I2C interface; the relevant calculation output code inside the chip is proportional to the voltage difference between the two analog inputs, and its full differential voltage input difference range is ±2.048V±0.05%.

[0015] The voltage divider circuit S2 includes a first resistor R137, a second resistor R144, a third resistor R140, a first TVS tube D38, a second TVS tube D13 and a third TVS tube D39; one end of the first resistor R137 serves as a first input end of the voltage divider circuit S2; the other end of the first resistor R137 is connected to the positive electrode of the first TVS tube D38, the positive electrode of the second TVS tube D13 and one end of the third resistor R140, and the connection point serves as a voltage output end of the voltage divider circuit S2; the other end of the third resistor R140 is connected to the negative electrode of the second TVS tube D13, the positive electrode of the third TVS tube D39 and one end of the second resistor R144, and the connection point serves as another voltage output end of the voltage divider circuit S2; the other end of the second resistor R144 serves as a second input end of the voltage divider circuit S2; the negative electrode of the first TVS tube D38 and the negative electrode of the third TVS tube D39 are both grounded.

[0016] Among them, the first resistor R137, the second resistor R144 and the third resistor R140 are connected in series, and the third resistor R140 is a sampling resistor. The high voltage between the PWR- pin and the PWR+ pin is converted into a low voltage signal at both ends of the third resistor R140 after resistor voltage division. The low voltage signal is isolated by a corresponding differential operational amplifier circuit S1 and then enters Figure 2 In addition, the resistance values ​​of the first resistor R137, the second resistor R144 and the third resistor R140 should be reasonably configured according to the voltage value of the new energy battery to ensure that the low voltage after the resistor voltage division is within the input voltage range of the analog-to-digital converter U20 after passing through the operational amplifier.

[0017] The differential operational amplifier circuit S1 includes an operational amplifier U17A, a fourth resistor R139, a fifth resistor R142, a sixth resistor R136, and a seventh resistor R146; one end of the fourth resistor R139 serves as a comparison signal input end of the differential operational amplifier circuit S1, and the other end of the fourth resistor R139 is connected to one end of the sixth resistor R136 and the negative input end of the operational amplifier U17A; one end of the fifth resistor R142 serves as another comparison signal input end of the differential operational amplifier circuit S1, and the other end of the fifth resistor R142 is connected to the seventh resistor R146. One end of the sixth resistor R146 and the positive input end of the operational amplifier U17A; the power supply end of the operational amplifier U17A is connected to a low-voltage power supply, and the reference voltage input end of the operational amplifier U17A is grounded; the other end of the sixth resistor R136 is connected to the output end of the operational amplifier U17A, and the connection point serves as the comparison signal output end of the differential operational amplifier circuit S1; the other end of the seventh resistor R146 is grounded; the resistance value of the seventh resistor R146 is equal to that of the sixth resistor R136, and the resistance value of the fifth resistor R142 is equal to that of the fourth resistor R139.

[0018] The operational amplifier U17A, the fourth resistor R139, the fifth resistor R142, the sixth resistor R136 and the seventh resistor R146 in the differential operational amplifier circuit S1 are combined to isolate the input voltage from the output voltage. Among them, the model of the operational amplifier U17A is SGM8542XS. In the differential operational amplifier circuit S1, R136=R146; R139=R142. According to the characteristics of virtual short and virtual disconnection of the operational amplifier, the operational amplifier output voltage V can be calculated. OUT = (V p -V n )×R136 / R146+V REF Since the reference voltage input terminal is grounded, V REF =0, R136=R146; then the output voltage V OUT = (V p -V n ).

[0019] In a more specific embodiment, the first TVS tube D38, the second TVS tube D13 and the third TVS tube D39 are all transient voltage suppression TVS tubes. Specifically, the voltage divider circuit S2 further includes a first capacitor C236 and a second capacitor C235; the first capacitor C236 is arranged in parallel at both ends of the first TVS tube D38; the second capacitor C235 is arranged in parallel at both ends of the third TVS tube D39.

[0020] The first TVS tube D38, the second TVS tube D13 and the third TVS tube D39 can be set to be transient voltage suppression TVS tubes (TVS tube, Transient Voltage Suppressor), the main function of which is to prevent static electricity and surges from damaging the operational amplifier U17A. The first capacitor C236 and the second capacitor C235 are mainly used for filtering and stabilizing voltage.

[0021] In a more specific embodiment, the differential operational amplifier circuit S1 also includes an eighth resistor R141 and a third capacitor C221; one end of the eighth resistor R141 is connected to the other end of the sixth resistor R136 and the output end of the operational amplifier U17A; the other end of the eighth resistor R141 is connected to one end of the third capacitor C221; the other end of the third capacitor C221 is grounded.

[0022] The eighth resistor R141 and the third capacitor C221 form an RC low-pass filter circuit, which is mainly used to prevent signal distortion problems such as output overshoot.

[0023] The differential operational amplifier circuit S1 further includes a fourth capacitor C198, a first ferromagnetic bead FB5, a fifth capacitor C200 and a sixth capacitor C219; one end of the fourth capacitor C198 is connected to the low-voltage power supply and one end of the first ferromagnetic bead FB5, and the other end of the first ferromagnetic bead FB5 is connected to one end of the fifth capacitor C200, one end of the sixth capacitor C219 and the power supply end of the operational amplifier U17A; the other end of the fourth capacitor C198, the other end of the fifth capacitor C200 and the other end of the sixth capacitor C219 are all grounded. Further, the differential operational amplifier circuit S1 further includes a ninth resistor R143, one end of the ninth resistor R143 is connected to the connection point between the eighth resistor R141 and the third capacitor C221, and the other end of the ninth resistor R143 is grounded.

[0024] The fourth capacitor C198, the first ferromagnetic bead FB5, the fifth capacitor C200 and the sixth capacitor C219 are mainly used to ensure that the input voltage of the low-voltage power supply remains stable. The output voltage of the low-voltage power supply is 3.3V.

[0025] In a more specific embodiment, the analog-to-digital conversion circuit S3 further includes a second ferromagnetic oxide bead FB6, a seventh capacitor C227, and an eighth capacitor C228; one end of the second ferromagnetic oxide bead FB6 is connected to the low-voltage power supply, and the other end of the second ferromagnetic oxide bead FB6 is connected to one end of the seventh capacitor C227, one end of the eighth capacitor C228, and the power supply pin of the analog-to-digital converter U20; the other end of the seventh capacitor C227 and the other end of the eighth capacitor C228 are both grounded. Specifically, the analog-to-digital conversion circuit S3 further includes a tenth resistor R147 and an eleventh resistor R149; the selection signal pin of the analog-to-digital converter U20 is connected to the tenth resistor R147, and the other end of the tenth resistor R147 serves as a selection signal transmission end; the data signal pin of the analog-to-digital converter U20 is connected to the eleventh resistor R149, and the other end of the eleventh resistor R149 serves as a data signal transmission end.

[0026] The second ferrite bead FB6, the seventh capacitor C227 and the eighth capacitor C228 are used to ensure that the voltage output to the analog-to-digital converter U20 remains stable.

[0027] The present application also discloses a voltage measurement method for a new energy vehicle battery, wherein the voltage measurement method is applied to a measurement terminal, and the measurement terminal is connected to the analog-to-digital converter in the voltage measurement circuit for the new energy vehicle battery; the measurement terminal can be a terminal device such as a laptop computer, a desktop computer, a tablet computer or a mobile phone. Figure 3 As shown, the voltage measurement method includes steps S110 to S130.

[0028] S110, if a digital signal is received from the analog-to-digital converter, the bit rate value corresponding to the current sampling frequency is obtained according to the preset sampling configuration table. The measurement terminal can send a configuration instruction to the analog-to-digital converter, thereby selecting a configuration parameter in the sampling configuration table that matches the configuration instruction and configuring parameters such as the sampling frequency. Different sampling frequencies correspond to different bit rates and different numbers of bits. The specific information of the sampling configuration table is shown in Table 1: Table 1

[0029] If a digital signal is received from a digital-to-analog converter, the bit rate value corresponding to the currently configured sampling frequency can be obtained according to the sampling configuration table. For example, if the currently configured sampling frequency is 60, a random bit rate value can be obtained from 8192 or 8191 as the corresponding bit rate value.

[0030] In a more specific embodiment, obtaining the bit rate value corresponding to the current sampling frequency according to a preset sampling configuration table includes: determining the numerical direction of the digital signal; and obtaining the corresponding bit rate value from the sampling configuration table according to the determined numerical direction and the current sampling frequency.

[0031] Furthermore, if the DC_DET_ADC1+ of the analog-to-digital converter receives a voltage signal, the digital signal output by the analog-to-digital converter is a positive value; if the DC_DET_ADC1- of the analog-to-digital converter receives a voltage signal, the digital signal output by the analog-to-digital converter is a negative value. The measurement terminal can judge the numerical direction of the numerical signal, that is, determine whether the numerical direction is positive or negative.

[0032] A more accurate bitrate value can be obtained by combining the numerical direction with the current sampling frequency. For example, if the numerical direction is positive and the sampling frequency is 60, the bitrate value can be determined to be 8191.

[0033] S120, converting the digital signal and the bit rate value according to a preset conversion formula to obtain a corresponding initial conversion voltage value.

[0034] Furthermore, the digital signal and the bit rate value can be converted according to the conversion formula, which can be expressed by formula (1): (1); in, Vp-Vn is the voltage difference across the third resistor, C is the input digital signal, r is the gain coefficient (related to the circuit characteristics of the differential operational amplifier circuit), Mc is the bit rate value obtained in the above step. Vp-Vn It can be used as the corresponding initial conversion voltage value.

[0035] S130, performing voltage division calculation on the initial conversion voltage according to a preset voltage division calculation formula to obtain a corresponding voltage measurement value.

[0036] Furthermore, the obtained initial conversion voltage is divided according to the voltage division calculation formula, so as to restore the voltage measurement value. The voltage division calculation formula can be expressed by formula (2): (2); By inverting formula (2), we can get the voltage value V at the battery end. PWR+ and V PWR- , then V PWR+ With V PWR- The difference between them is the final voltage measurement value. The voltage measurement circuit combined with the voltage measurement method can achieve the purpose of measuring the battery voltage of new energy vehicles by using a voltage measurement circuit designed based on low-cost components.

[0037] The present invention discloses a voltage measurement circuit and a voltage measurement method for a new energy vehicle battery. The voltage measurement circuit includes two voltage divider circuits, two differential operational amplifier circuits and an analog-to-digital conversion circuit, wherein the first input end of one voltage divider circuit and the second input end of another voltage divider circuit are simultaneously connected to a battery voltage input end of a battery connection seat, and the second input end of one voltage divider circuit and the first input end of another voltage divider circuit are simultaneously connected to another battery voltage input end of the battery connection seat; the two voltage output ends of each voltage divider circuit are respectively connected to a comparison signal input end of a differential operational amplifier circuit; the analog-to-digital conversion circuit includes an analog-to-digital converter, and the first voltage transmission pin and the second voltage transmission pin of the analog-to-digital converter are respectively connected to the comparison signal output ends of two differential operational amplifier circuits. The above-mentioned voltage measurement circuit reduces costs by simplifying the circuit setting structure; the use of a differential operational amplifier circuit can effectively improve the detection accuracy and realize high and low voltage isolation to avoid high voltage from damaging the subsequent circuit components, increase the reliability of voltage measurement, and has the application effect of low energy consumption and improved performance of the circuit system.

[0038] The above are only specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed by the present invention, and these modifications or replacements should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be based on the protection scope of the claims.

Claims

1. A voltage measurement circuit for a new energy vehicle battery, characterized in that: The voltage measurement circuit includes two voltage divider circuits, two differential operational amplifier circuits and an analog-to-digital conversion circuit; The first input end of one of the voltage divider circuits and the second input end of the other voltage divider circuit are simultaneously connected to a battery voltage input end of a battery connection socket, and the second input end of one of the voltage divider circuits and the first input end of the other voltage divider circuit are simultaneously connected to another battery voltage input end of the battery connection socket; The two voltage output terminals of each voltage divider circuit are respectively connected to a comparison signal input terminal of the differential operational amplifier circuit; the analog-to-digital conversion circuit includes an analog-to-digital converter, and the first voltage transmission pin and the second voltage transmission pin of the analog-to-digital converter are respectively connected to the comparison signal output terminals of the two differential operational amplifier circuits; The voltage divider circuit includes a first resistor, a second resistor, a third resistor, a first TVS tube, a second TVS tube and a third TVS tube; one end of the first resistor serves as a first input end of the voltage divider circuit; the other end of the first resistor is connected to the positive electrode of the first TVS tube, the positive electrode of the second TVS tube and one end of the third resistor, and the connection point serves as a voltage output end of the voltage divider circuit; the other end of the third resistor is connected to the negative electrode of the second TVS tube, the positive electrode of the third TVS tube and one end of the second resistor, and the connection point serves as another voltage output end of the voltage divider circuit; the other end of the second resistor serves as a second input end of the voltage divider circuit; the negative electrode of the first TVS tube and the negative electrode of the third TVS tube are both grounded; The differential operational amplifier circuit includes an operational amplifier, a fourth resistor, a fifth resistor, a sixth resistor and a seventh resistor; one end of the fourth resistor serves as a comparison signal input end of the differential operational amplifier circuit, and the other end of the fourth resistor is connected to one end of the sixth resistor and the negative input end of the operational amplifier; one end of the fifth resistor serves as another comparison signal input end of the differential operational amplifier circuit, and the other end of the fifth resistor is connected to one end of the seventh resistor and the positive input end of the operational amplifier; the power supply end of the operational amplifier is connected to a low-voltage power supply, and the reference voltage input end of the operational amplifier is grounded; The other end of the sixth resistor is connected to the output end of the operational amplifier, and the connection point serves as the comparison signal output end of the differential operational amplifier circuit; the other end of the seventh resistor is grounded; the resistance value of the seventh resistor is equal to that of the sixth resistor, and the resistance value of the fifth resistor is equal to that of the fourth resistor.

2. The voltage measurement circuit for a new energy vehicle battery according to claim 1, characterized in that: The voltage divider circuit also includes a first capacitor and a second capacitor; The first capacitor is connected in parallel at both ends of the first TVS tube; the second capacitor is connected in parallel at both ends of the third TVS tube.

3. The voltage measurement circuit for a new energy vehicle battery according to claim 2, characterized in that: The differential operational amplifier circuit further includes an eighth resistor and a third capacitor; One end of the eighth resistor is connected to the other end of the sixth resistor and the output end of the operational amplifier; the other end of the eighth resistor is connected to one end of the third capacitor; and the other end of the third capacitor is grounded.

4. The voltage measurement circuit for a new energy vehicle battery according to claim 3, characterized in that: The differential operational amplifier circuit further includes a fourth capacitor, a first ferromagnetic bead, a fifth capacitor and a sixth capacitor; One end of the fourth capacitor is connected to the low-voltage power supply and one end of the first oxygen-ferromagnetic bead, and the other end of the first oxygen-ferromagnetic bead is connected to one end of the fifth capacitor, one end of the sixth capacitor and the power supply end of the operational amplifier; the other end of the fourth capacitor, the other end of the fifth capacitor and the other end of the sixth capacitor are all grounded.

5. The voltage measurement circuit for a new energy vehicle battery according to claim 4, characterized in that: The differential operational amplifier circuit further includes a ninth resistor, one end of the ninth resistor is connected to a connection point between the eighth resistor and the third capacitor, and the other end of the ninth resistor is grounded.

6. The voltage measurement circuit for a new energy vehicle battery according to claim 2, characterized in that: The analog-to-digital conversion circuit also includes a second ferromagnetic bead, a seventh capacitor and an eighth capacitor; One end of the second oxygen ferromagnetic bead is connected to the low-voltage power supply, and the other end of the second oxygen ferromagnetic bead is connected to one end of the seventh capacitor, one end of the eighth capacitor and the power supply pin of the analog-to-digital converter; the other end of the seventh capacitor and the other end of the eighth capacitor are both grounded.

7. The voltage measurement circuit for a new energy vehicle battery according to claim 6, characterized in that: The analog-to-digital conversion circuit further includes a tenth resistor, a selection signal pin of the analog-to-digital converter is connected to the tenth resistor, and the other end of the tenth resistor serves as a selection signal transmission end.

8. The voltage measurement circuit for a new energy vehicle battery according to claim 6, characterized in that: The analog-to-digital conversion circuit also includes an eleventh resistor; the data signal pin of the analog-to-digital converter is connected to the eleventh resistor, and the other end of the eleventh resistor serves as a data signal transmission end.

9. A voltage measurement method for a new energy vehicle battery, characterized in that: The voltage measurement method is applied to a measurement terminal, the measurement terminal is communicatively connected to an analog-to-digital converter in a voltage measurement circuit for a new energy vehicle battery according to any one of claims 1 to 8, and the voltage measurement method comprises: If a digital signal is received from the analog-to-digital converter, a code rate value corresponding to the current sampling frequency is obtained according to a preset sampling configuration table; Convert the digital signal and the bit rate value according to a preset conversion formula to obtain a corresponding initial conversion voltage value; The initial conversion voltage is divided and calculated according to a preset voltage division calculation formula to obtain a corresponding voltage measurement value.

10. The voltage measurement method for a new energy vehicle battery according to claim 9, characterized in that: The step of obtaining a bit rate value corresponding to the current sampling frequency according to a preset sampling configuration table includes: Determining the numerical direction of the digital signal; The corresponding bit rate value is obtained from the sampling configuration table according to the determined numerical direction and the current sampling frequency.

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