CN-116577565-B - Method and device for detecting capacitance of power battery, storage medium and electronic device

CN116577565BCN 116577565 BCN116577565 BCN 116577565BCN-116577565-B

Abstract

The invention discloses a method and a device for detecting capacitance of a power battery, a storage medium and an electronic device, and relates to the technical field of vehicles. The method comprises the steps of receiving a target control instruction, controlling the on state of a switch according to a preset sequence, determining a first voltage of a first resistor, a second voltage of a second resistor, a third voltage of a third resistor and a fourth voltage of a fourth resistor, wherein the first resistor, the second resistor, the third resistor and the fourth resistor are positioned outside a power battery, the power battery comprises a target capacitor, determining a target capacitance value of the target capacitor according to the first voltage, the second voltage, the third voltage, the fourth voltage and an equivalent resistance value, and detecting the target capacitor based on the target capacitance value. The invention solves the technical problems that the method is limited, not easy to realize and the detection accuracy is lower because the related technology is based on important assumption by carrying out Y capacitance detection on the power battery in the electric automobile.

Inventors

SHENG YI
LI WEI
JIANG TAO
JIANG LEI
CHEN DESONG
ZHANG XINGSHUO
MENG FANQI

Assignees

中国第一汽车股份有限公司

Dates

Publication Date: 20260512
Application Date: 20230519

Claims (9)

1. A method for detecting capacitance of a power battery, comprising: Receiving a target control instruction, and according to a preset sequence, controlling the on state of a switch, determining a first voltage of a first resistor, a second voltage of a second resistor, a third voltage of a third resistor and a fourth voltage of a fourth resistor, wherein the first resistor, the second resistor, the third resistor and the fourth resistor are positioned outside a power battery, and the power battery comprises a target capacitor; determining a target capacitance value of the target capacitance according to the first voltage, the second voltage, the third voltage, the fourth voltage and an equivalent resistance value, wherein the equivalent resistance value is a resistance value of an equivalent resistance of the first resistor, the second resistor, a fifth resistor and a sixth resistor, and the power battery further comprises the fifth resistor and the sixth resistor; detecting the target capacitance based on the target capacitance value; The method comprises the steps of determining a target capacitance value of the target capacitor according to the first voltage, the second voltage, the third voltage, the fourth voltage and an equivalent resistance value, determining a first current according to a fifth voltage and the resistance value of the third resistor, and determining a second current according to a sixth voltage and the resistance value of the fourth resistor, wherein the first current is the current of the third resistor, the second current is the current of the fourth resistor, the fifth voltage and the sixth voltage are transient voltages of the first resistor and the second resistor respectively, performing first deformation processing on the first current based on the equivalent resistance value, determining a first target current, performing second deformation processing on the second current based on the equivalent resistance value, determining a second target current, performing processing on the first target current based on the first voltage and the third voltage, determining a first target voltage, performing processing on the second target current based on the second voltage and the fourth voltage, and determining the target capacitance value according to the first target voltage and the second target capacitance value.
2. The method of claim 1, wherein the processing the first target current based on the first voltage and the third voltage, determining a first target voltage, and processing the second target current based on the second voltage and the fourth voltage, determining a second target voltage comprises: performing third deformation processing on the first current based on the first voltage and the third voltage to obtain a first initial voltage, and performing fourth deformation processing on the second current based on the second voltage and the fourth voltage to obtain a second initial voltage; And performing fifth deformation processing on the first initial voltage based on a first moment to obtain the first target voltage, and performing sixth deformation processing on the second initial voltage based on a second moment to obtain the second target voltage, wherein the first moment and the second moment are outside a preset time period after the initial moment.
3. The method of claim 1, wherein said determining said target capacitance value from said first target voltage and said second target voltage comprises: And carrying out offset processing on the equivalent resistance value according to the first target voltage and the second target voltage to obtain the target capacitance value.
4. The method of claim 1, wherein the target control command comprises a first control command, a second control command, and a third control command, wherein the receiving the target control command, controlling the on state of the switch according to a preset sequence, and determining the first voltage of the first resistor, the second voltage of the second resistor, the third voltage of the third resistor, and the fourth voltage of the fourth resistor comprises: The first control instruction is received, the first voltage of the first resistor and the second voltage of the second resistor are determined, and the first control instruction is used for controlling the first switch, the second switch and the third switch to be conducted; The second control instruction is received, the third voltage of the third resistor is determined, wherein the second control instruction is used for controlling the first switch, the second switch, the third switch and the fourth switch to be conducted, and the fourth switch is used for controlling the third resistor to be connected in parallel with the first resistor; And receiving the third control instruction, and determining the fourth voltage of the fourth resistor, wherein the second control instruction is used for controlling the first switch, the second switch, the third switch and a fifth switch to be conducted, and the fifth switch is used for controlling the fourth resistor to be connected in parallel with the second resistor.
5. The method of any one of claims 1-4, further comprising: determining a total voltage of the power cells; And responding to the fact that the difference value between the sum of the voltage of the first resistor and the voltage of the second resistor and the total voltage is larger than or equal to a first voltage threshold, the voltage fluctuation of the first resistor is larger than or equal to a second voltage threshold, and the voltage fluctuation of the second resistor is larger than or equal to the second voltage threshold, and reporting error prompt information, wherein the error prompt information is used for representing detection flow errors.
6. A capacitance detection circuit of a power battery, characterized in that it is used to perform the capacitance detection method of a power battery as set forth in any one of claims 1 to 5, the capacitance detection circuit of a power battery including a battery, a fifth resistor, a sixth resistor, and a target capacitance, The positive electrode of the power battery is coupled with the first end of the first switch, the second end of the first switch is coupled with the first end of the first resistor, the second end of the first resistor is coupled with the first end of the third switch, the second end of the third switch is coupled with the grounding end of the power battery, A first end of the first resistor is coupled to a first end of the fourth switch, a second end of the fourth switch is coupled to a first end of the third resistor, a second end of the third resistor is coupled to a first end of the third switch, The second end of the third resistor is coupled with the first end of the fourth resistor, the second end of the fourth resistor is coupled with the first end of the fifth switch, the second end of the fifth switch is coupled with the first end of the second switch, the second end of the second switch is coupled with the negative electrode of the power battery, The second end of the first resistor is coupled with the first end of the second resistor, the second end of the second resistor is coupled with the first end of the second switch, and the first end of the third switch is grounded.
7. A capacitance detection device of a power battery, comprising: The control module is used for receiving a target control instruction, controlling the on state of the switch according to a preset sequence, and determining a first voltage of a first resistor, a second voltage of a second resistor, a third voltage of a third resistor and a fourth voltage of a fourth resistor, wherein the first resistor, the second resistor, the third resistor and the fourth resistor are positioned outside the power battery, and the power battery comprises a target capacitor; the determining module is used for determining a target capacitance value of the target capacitance according to the first voltage, the second voltage, the third voltage, the fourth voltage and an equivalent resistance value, wherein the equivalent resistance value is a resistance value of an equivalent resistance of the first resistor, the second resistor, a fifth resistor and a sixth resistor, and the power battery further comprises the fifth resistor and the sixth resistor; The detection module is used for detecting the target capacitance based on the target capacitance value; The determining module is further configured to determine a first current according to a fifth voltage and a resistance value of the third resistor, and determine a second current according to a sixth voltage and a resistance value of the fourth resistor, wherein the first current is a current of the third resistor, the second current is a current of the fourth resistor, the fifth voltage and the sixth voltage are transient voltages of the first resistor and the second resistor, respectively, perform a first deformation process on the first current based on the equivalent resistance value, determine a first target current, and perform a second deformation process on the second current based on the equivalent resistance value, determine a first target voltage, and determine a second target voltage based on the first voltage and the third voltage, and perform a process on the second target current, determine a second target voltage based on the second voltage and the fourth voltage, and determine the target capacitance value according to the first target voltage and the second target voltage.
8. A computer readable storage medium, characterized in that the computer readable storage medium has stored therein a computer program, wherein the computer program is arranged to perform the method of capacitance detection of a power cell as claimed in any of the preceding claims 1 to 5 when run on a computer or processor.
9. An electronic device comprising a memory and a processor, characterized in that the memory has stored therein a computer program, the processor being arranged to run the computer program to perform the method of capacitance detection of a power cell as claimed in any of the preceding claims 1 to 5.

Description

Method and device for detecting capacitance of power battery, storage medium and electronic device Technical Field The present invention relates to the field of vehicle technologies, and in particular, to a method and an apparatus for detecting capacitance of a power battery, a storage medium, and an electronic apparatus. Background With the rapid development of electric vehicles, the safety and reliability of a high-voltage system, which is one of the electric vehicle marks, are receiving more and more attention. Because of factors such as electromagnetic interference and objective environment, a capacitor, namely a Y capacitor, exists between the high-voltage system and the low-voltage system, and the high-voltage system of the electric automobile often has potential safety hazards of high-voltage electric shock. Therefore, to ensure that the energy stored by the Y capacitance does not cause personnel to get at risk of electric shock, accurate detection of the Y capacitance is necessary. At present, Y capacitance detection is carried out On a high-voltage assembly, namely a power battery, of a vehicle-mounted rechargeable energy storage system (On-board rechargeable energy storage system, REESS) in an electric vehicle, and a circuit comprising the power battery, the Y capacitance, an insulation resistor, a balance resistor, a discharge resistor and a switch is built, so that the voltage change characteristic of the Y capacitance is observed and recorded, and the specific value of the Y capacitance is analyzed and calculated. However, the method is based on an important assumption that the method is limited and not easy to realize, and the important assumption is often not true, and meanwhile, the precision of the resistor and the accumulation of deviation have certain influence on the result of the Y capacitance, so that the detection accuracy is low. In view of the above problems, no effective solution has been proposed at present. Disclosure of Invention The embodiment of the invention provides a capacitance detection method and device of a power battery, a storage medium and an electronic device, which at least solve the technical problems that the method is limited, the implementation is difficult and the detection accuracy is low because the Y capacitance detection is carried out on the power battery in an electric automobile on the basis of important assumption in the related technology. According to one embodiment of the invention, a capacitance detection method of a power battery is provided, which comprises the steps of receiving a target control command, controlling the on state of a switch according to a preset sequence, determining a first voltage of a first resistor, a second voltage of a second resistor, a third voltage of a third resistor and a fourth voltage of a fourth resistor, wherein the first resistor, the second resistor, the third resistor and the fourth resistor are positioned outside the power battery, the power battery comprises a target capacitance, and determining a target capacitance value of the target capacitance according to the first voltage, the second voltage, the third voltage, the fourth voltage and an equivalent resistance value, wherein the equivalent resistance value is an equivalent resistance value of the first resistor, the second resistor, the fifth resistor and the sixth resistor, and detecting the target capacitance based on the target capacitance value. Optionally, determining the target capacitance value of the target capacitor according to the first voltage, the second voltage, the third voltage, the fourth voltage and the equivalent resistance value comprises determining a first current according to the resistance values of a fifth voltage and a third resistor, determining a second current according to the resistance values of a sixth voltage and a fourth resistor, wherein the first current is the current of the third resistor, the second current is the current of the fourth resistor, the fifth voltage and the sixth voltage are transient voltages of the first resistor and the second resistor respectively, performing first deformation processing on the first current based on the equivalent resistance value, determining a first target current, performing second deformation processing on the second current based on the equivalent resistance value, determining a second target current, performing processing on the first target current based on the first voltage and the third voltage, determining a first target voltage, and performing processing on the second target current based on the second voltage and the fourth voltage, determining a target capacitance value according to the first target voltage and the second target voltage. Optionally, processing the first target current based on the first voltage and the third voltage, determining the first target voltage, and processing the second target current based on the second voltage and the fourth voltage, wherei