CN114878984A - Insulation test device and insulation test method - Google Patents
Insulation test device and insulation test method Download PDFInfo
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- CN114878984A CN114878984A CN202210476377.9A CN202210476377A CN114878984A CN 114878984 A CN114878984 A CN 114878984A CN 202210476377 A CN202210476377 A CN 202210476377A CN 114878984 A CN114878984 A CN 114878984A
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/12—Testing dielectric strength or breakdown voltage ; Testing or monitoring effectiveness or level of insulation, e.g. of a cable or of an apparatus, for example using partial discharge measurements; Electrostatic testing
- G01R31/1227—Testing dielectric strength or breakdown voltage ; Testing or monitoring effectiveness or level of insulation, e.g. of a cable or of an apparatus, for example using partial discharge measurements; Electrostatic testing of components, parts or materials
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/10—Energy storage using batteries
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Abstract
The invention discloses an insulation testing device and an insulation testing method. The insulation testing device is used for testing the battery pack, the battery pack comprises a shell and an electric core arranged in the shell, and the insulation testing device comprises a signal generator and an insulation sampling circuit. The signal generator is used for generating damped oscillation waves as detection waves, and the detection waves are used for being input between the battery cell and the shell. The insulation sampling circuit is used for collecting a detection electric signal generated when the detection wave passes through the battery pack and determining whether the battery pack is partially discharged or not according to the detection electric signal. In the insulation test device and the insulation test method, the damped oscillation waves can be input into the battery pack as the detection waves, whether the battery pack has partial discharge can be determined according to the detection electric signals generated when the detection waves pass through the battery pack, and therefore the insulation performance test of the battery pack is achieved, wherein when the battery pack has partial discharge, the battery pack can be considered to have an insulation failure point or an insulation weak point.
Description
Technical Field
The invention relates to a battery insulation test technology, in particular to an insulation test device and an insulation test method.
Background
In a scenario where the battery pack is used (e.g., a new energy automobile), the safety of the battery pack is crucial, and the insulating property of the battery pack is an important property for the safety of the battery pack. In the related art, in order to ensure the safety of the battery pack, it is necessary to perform an insulation performance test on the battery pack.
Disclosure of Invention
The invention provides an insulation test device and an insulation test method.
The insulation testing device can be used for testing a battery pack, the battery pack comprises a shell and a battery cell arranged in the shell, and the insulation testing device comprises a signal generator and an insulation sampling circuit. The signal generator is used for generating damped oscillation waves as detection waves, and the detection waves are used for being input between the battery cell and the shell. The insulation sampling circuit is used for collecting a detection electric signal generated when the detection wave passes through the battery pack and determining whether the battery pack is partially discharged or not according to the detection electric signal.
In some embodiments, the battery pack includes a main positive relay connected to the positive electrode of the battery cell and a main negative relay connected to the negative electrode of the battery cell, the main positive relay and the main negative relay generate a damped oscillation wave as a test wave when closed, the insulation sampling circuit is further configured to collect a test electrical signal corresponding to the test wave when the signal generator is disconnected, and determine the frequency of the test wave according to the test electrical signal, the signal generator is configured to generate the detection wave according to the frequency of the test wave, and the frequency of the detection wave is the same as the frequency of the test wave.
In some embodiments, the insulated sampling circuit includes a sampling chip, a first resistor and a second resistor arranged in series, the sampling chip is connected between the first resistor and the second resistor, and the sampling chip is used for collecting the frequency of the test wave.
In some embodiments, the insulation test apparatus further comprises a power amplifier and a power supply, the power supply is used for supplying power to the power amplifier, and the power amplifier is used for amplifying the detection wave output by the signal generator.
In some embodiments, the detection electrical signal includes a pulse current, the insulation sampling circuit includes a sampling chip, a first capacitor and a second capacitor, the first capacitor and the second capacitor are connected in series, the sampling chip is connected between the first capacitor and the second capacitor, and the sampling chip is configured to collect the pulse current generated when the detection wave passes through the battery pack and determine that partial discharge occurs in the battery pack when the pulse current exists.
In some embodiments, the detection electrical signal includes a response wave and a pulse current, the response wave is a damped oscillation wave generated when the detection wave passes through the battery pack, the insulation sampling circuit includes a sampling chip, a first resistor and a second resistor arranged in series, and a first capacitor and a second capacitor arranged in series, the sampling chip is connected between the first resistor and the second resistor and between the first capacitor and the second capacitor, the sampling chip is configured to collect a waveform and a frequency of the response wave and the pulse current generated when the detection wave passes through the battery pack, and determine whether the partial discharge occurs in the battery pack according to the waveform and the frequency of the response wave and the pulse current.
In some embodiments, the battery pack includes a main positive relay connected to the positive electrode of the cell and a main negative relay connected to the negative electrode of the cell, the main positive relay is output through a total positive cable, the total negative relay is output through a total negative cable, and the detection wave is input between the total positive cable and the casing or the detection wave is input between the total negative cable and the casing.
In some embodiments, the signal generator is configured to generate the detection wave a plurality of times; the insulation sampling circuit is used for collecting a plurality of detection electric signals generated when the detection waves pass through the battery pack for a plurality of times, and determining whether the battery pack is partially discharged or not according to the plurality of detection electric signals.
In some embodiments, the battery pack includes a battery management system, the insulation sampling circuit is integrated in the battery management system, or the insulation sampling circuit is provided separately from the battery pack.
The insulation test method can be used for testing a battery pack, wherein the battery pack comprises a shell and a battery core arranged in the shell, and the insulation test method comprises the following steps: generating a damped oscillation wave as a detection wave and inputting the detection wave between the battery cell and the casing; collecting a detection electric signal generated when the detection wave passes through the battery pack; and determining whether the partial discharge of the battery pack occurs according to the detection electric signal.
In the insulation test device and the insulation test method, the damped oscillation waves are input into the battery pack as the detection waves, whether the battery pack has partial discharge or not can be determined according to the detection electric signals generated when the detection waves pass through the battery pack, and therefore the insulation performance test of the battery pack is achieved, wherein when the battery pack has partial discharge, the battery pack can be considered to have an insulation failure point or an insulation weak point.
Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.
Drawings
The above and/or additional aspects and advantages of the present invention will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:
FIG. 1 is a schematic diagram of the connection of the insulation testing apparatus of the present invention to a battery pack;
fig. 2 is a schematic flow chart of the insulation testing method of the present invention.
Fig. 3 is a schematic diagram of a detection wave of the present invention.
Fig. 4 is a schematic diagram of the response wave and the pulse current of the present invention.
Description of the main element symbols:
the insulation testing device 10, the signal generator 11, the insulation sampling circuit 13, the sampling chip 131, the first resistor 133, the second resistor 135, the first capacitor 137, the second capacitor 139, the power amplifier 15, the power supply 17, the battery pack 20, the housing 21, the battery cell 22, the main positive relay 23, the main negative relay 24, the connecting member 25, the total positive cable 26, the total negative cable 27, and the battery management system 28.
Detailed Description
Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the drawings are illustrative and intended to be illustrative of the invention and are not to be construed as limiting the invention.
In a scenario where the battery pack is used (e.g., a new energy automobile), the safety of the battery pack is crucial, and the insulating property of the battery pack is an important property for the safety of the battery pack. In the related art, in order to ensure the safety of the battery pack, it is necessary to perform an insulation performance test on the battery pack.
In the related art, the insulation performance test of the battery pack mainly includes a direct current withstand voltage test and an alternating current withstand voltage test. The direct current withstand voltage test has the following defects that the direct current withstand voltage test cannot test partial discharge; secondly, the insulation performance of the battery pack is damaged by the direct-current voltage withstand test, the insulating layer still maintains the molecular arrangement in the polarization state in a period after the high voltage of the direct-current voltage withstand test is removed, and the molecular arrangement is not easy to recover to the state before the direct-current high voltage is applied. The alternating current withstand voltage test is generally a power frequency 50hz alternating current withstand voltage test, although the damage to the battery pack is slightly small, the battery pack can only break down serious defects generally, and the defects which are not serious enough can stimulate development (the defects become easier to break down) and cannot break down necessarily. And because the battery package is because the difference of its equivalent inductance and equivalent capacitance, so lead to the high-pressure return circuit resonant frequency of every battery package inconsistent, simply use power frequency 50hz to test and can not simulate the actual working condition of battery package.
Referring to fig. 1, the insulation testing device 10 of the present invention can be used for testing a battery pack 20. The battery pack 20 includes a casing 21 and a battery cell 22 disposed in the casing 21, and the insulation test apparatus 10 includes a signal generator 11 and an insulation sampling circuit 13. The signal generator 11 is configured to generate a damped oscillation wave as a detection wave, and the detection wave is input between the battery cell 22 and the casing 21. The insulation sampling circuit 13 is configured to collect a detection electrical signal generated when the detection wave passes through the battery pack 20, and determine whether the battery pack 20 has been partially discharged according to the detection electrical signal.
Referring to fig. 1 and fig. 2, the insulation testing method of the present invention may be used for testing a battery pack 20, where the battery pack 20 includes a casing 21 and a battery cell 22 disposed in the casing 21, and the insulation testing method includes:
01: generating a damped oscillation wave as a detection wave and inputting the detection wave between the battery cell 22 and the case 21;
02: collecting a detection electric signal generated when the detection wave passes through the battery pack 20;
03: it is determined whether the partial discharge of the battery pack 20 has occurred based on the detected electric signal.
The insulation test method of the present application can be implemented by the insulation test apparatus 10 of the present application, wherein step 01 can be implemented by the signal generator 11, and steps 02 and 03 can be implemented by the insulation sampling circuit 13.
In the insulation test apparatus 10 and the insulation test method, the damped oscillation wave is input to the battery pack 20 as the detection wave, and whether the battery pack 20 has partial discharge or not can be determined according to the detection electric signal generated when the detection wave passes through the battery pack 20, so as to realize the insulation performance test of the battery pack 20, wherein when the battery pack 20 has partial discharge, it can be considered that the battery pack 20 has an insulation failure point or an insulation weak point.
In some embodiments, the battery pack 20 may be a power battery of a new energy vehicle.
Referring to fig. 3, the damped oscillatory wave may refer to an electrical signal whose amplitude gradually attenuates with time, wherein the horizontal axis represents time and the vertical axis represents voltage. The signal generator 11 may be any circuit capable of generating a damped oscillatory wave, and for example, the signal generator may be a CPU or MCU connected to a preset output circuit, and the CPU or MCU may output the damped oscillatory wave through the preset output circuit.
The damped oscillation waves are input between the battery core 22 and the shell 21 as detection waves, the shell 21 is connected with the ground, and the detection waves can generate different detection electric signals after passing through the battery pack 20 due to different insulation performances of the battery pack 20, so that whether partial discharge occurs in the battery pack 20 can be determined according to the detection electric signals, and the insulation performance of the battery pack 20 can be determined.
In some embodiments, the insulation sampling circuit 13 has a processing function, and is capable of processing the detection electrical signal to determine whether the battery pack 20 has been partially discharged. In some embodiments, the isolated sampling circuit 13 does not have a processing function, and the isolated sampling circuit 13 may send the detection electrical signal to a processing element for processing to determine whether the partial discharge of the battery pack 20 has occurred.
In the insulation test apparatus 10 and the insulation test method, the insulation test may be performed before the battery pack 20 is shipped. When the battery pack 20 is partially discharged, it can be determined that the battery pack 20 has an insulation failure point or an insulation weak point, and therefore it can be determined that the battery pack 20 has poor insulation performance and the battery pack 20 cannot be shipped; when the partial discharge of the battery pack 20 does not occur, it can be determined that the battery pack 20 does not have an insulation failure point or an insulation weak point, and thus it can be determined that the insulation performance of the battery pack 20 is good and the battery pack 20 can be shipped normally.
The present invention performs the insulation performance detection using the damped oscillation wave as the detection, and therefore, the insulation performance of the battery pack 20 is not damaged. The direct-current voltage withstand test can damage the insulating property of the battery pack, the insulating layer can still maintain the molecular arrangement in the polarization state in a period after the high voltage of the direct-current voltage withstand test is removed, and the molecular arrangement is not easy to recover to the state before the direct-current high voltage is applied.
Referring to fig. 1, in some embodiments, the battery pack 20 includes a main positive relay 23 connected to the positive electrode of the battery cell 22 and a main negative relay 24 connected to the negative electrode of the battery cell 22, the main positive relay 23 and the main negative relay 24 generate a damped oscillation wave as a test wave when closed, the insulation sampling circuit 13 is further configured to collect a test electrical signal corresponding to the test wave when the signal generator 11 is open, and determine a frequency of the test wave according to the test electrical signal, and the signal generator 11 is configured to generate a detection wave according to the frequency of the test wave, where the frequency of the detection wave is the same as the frequency of the test wave.
In some embodiments, the battery pack 20 includes a main positive relay 23 connected to the positive pole of the battery cell 22 and a main negative relay 24 connected to the negative pole of the battery cell 22, and the insulation testing method further includes:
04: a disconnection signal generator 11;
05: closing the main positive relay 23 and the main negative relay 24 to generate a damped oscillation wave as a test wave;
06: collecting a test electric signal corresponding to the test wave, and determining the frequency of the test wave according to the test electric signal;
the step 01 comprises the following steps:
012: and generating a detection wave according to the frequency of the test wave, wherein the frequency of the detection wave is the same as that of the test wave.
Specifically, the battery pack 20 further includes a connecting member 25, the connecting member 25 is, for example, a high-voltage copper bar, the positive electrode of the battery cell 22 is connected to the main positive relay 23 through the high-voltage copper bar, the negative electrode of the battery cell 22 is connected to the main negative relay 24 through the high-voltage copper bar, and there may be a partial discharge or a short circuit at a high voltage of the battery cell 22 because an insulation failure point or an insulation weak point is caused by the design or the manufacturing process of the battery cell 22, the copper bar, the wire harness, and the like.
When the main positive relay 23 and the main negative relay 24 are closed, because the voltage difference between the voltages at the front and rear ends of the relay contacts before closing the relay is very large, when the voltages at the front and rear ends of the relay contacts after closing the relay become the same, because the steep wave front time (time from beginning to becoming the maximum voltage value) of the instantaneous change of the voltage reaches the order of tens of nanoseconds, when the voltage is transmitted on a high-voltage loop, the steep wave phenomenon can be relieved by the capacitance formed by all the high-voltage components in the battery pack 20, so that a damped oscillation wave (test wave) can be formed in the high-voltage loop, the frequency of the test wave is related to the parameters of the parasitic inductance, the parasitic capacitance and the like of the battery pack 20, and therefore, the frequency of the test wave of each battery pack 20 has a certain difference. Before the main positive relay 23 and the main negative relay 24 are closed, the signal generator 11 is turned off, so that the detection wave generated by the signal generator 11 is prevented from influencing the acquisition of the test wave.
The frequency f of the test wave is detected, and a damped oscillation wave with the frequency f is generated by the signal generator 11 as a detection wave, and then the detection wave can be input between the battery cell 22 and the casing 21. The frequency of the detection waves of the invention is different according to different battery packs, the frequency of the test waves is adopted as the frequency of the detection waves, the frequency of the test waves is the natural resonant frequency of the battery pack 20 and can better represent the working condition of the battery pack 20, and therefore, the detection waves can better detect the insulation performance of the battery pack 20.
When the insulation sampling circuit 13 collects the detection electric signal, the main positive relay 23 and the main negative relay 24 are closed.
Referring to fig. 1, in some embodiments, the insulation sampling circuit 13 includes a sampling chip 131, a first resistor 133 and a second resistor 135 connected in series, the sampling chip 131 is connected between the first resistor 133 and the second resistor 135, and the sampling chip 131 is used for collecting the frequency of the test wave.
In some embodiments, the insulated sampling circuit 13 includes a sampling chip 131, a first resistor 133 and a second resistor 135 arranged in series, the sampling chip 131 is connected between the first resistor 133 and the second resistor 135, and the step 02 includes:
022: the frequency of the test wave is collected by the sampling chip 131.
In this way, a sampling circuit can be formed by the first resistor 133 and the second resistor 135, so that information of the obtained test wave can be collected.
Specifically, by the first resistor 133 and the second resistor 135 which are arranged in series, the sampling chip 131 can collect the damped oscillation waves (test waves) generated when the main positive relay 23 and the main negative relay 24 are closed, so that the frequency of the test waves can be calculated.
Referring to fig. 1, in some embodiments, the insulation testing apparatus 10 further includes a power amplifier 15 and a power supply 17, the power supply 17 is configured to supply power to the power amplifier 15, and the power amplifier 15 is configured to amplify the detection wave output by the signal generator 11.
In some embodiments, the insulation testing apparatus 10 further includes a power amplifier 15 and a power supply 17, the power supply 17 being configured to supply power to the power amplifier 15, and the insulation testing method further includes:
07: the detection wave output from the signal generator 11 is amplified by a power amplifier 15.
In this way, the detection wave is amplified by the power amplifier 15, and then the amplified detection wave is input between the battery cell 22 and the casing 21, wherein the amplified detection wave is easier to break down an insulation failure point or an insulation weak point, so that the insulation performance of the battery pack 20 can be detected more accurately. The power supply 17 may be a power supply independent of the battery pack 20, and the power supply 17 is used to supply power to the power amplifier 15 so that the power amplifier 15 can amplify the detection wave.
In some embodiments, the voltage of the amplified detection wave is greater than the total voltage of the battery pack 20, and the voltage of the power source 17 is greater than the total voltage of the battery pack 20.
Thus, the amplified detection wave more easily breaks down the insulation failure point or insulation weak point, so that the insulation performance of the battery pack 20 can be more accurately detected. Wherein the voltage of the power supply 17 is greater than the total voltage of the battery pack 20, so that the power supply 17 can provide enough energy for the power amplifier 15, so that the power amplifier 15 can amplify the voltage of the detection wave to be greater than the total voltage of the battery pack 20. In some embodiments, the voltage of the amplified detection wave is greater than the total voltage of the battery pack 20 and less than the preset voltage, so that the amplified detection wave can be prevented from erroneously breaking down the normal battery pack 20. In one embodiment, the voltage of the amplified detection wave is twice the total voltage of the battery pack 20.
In some embodiments, the insulation sampling circuit 13 is configured to collect a test electrical signal corresponding to the test wave, and determine a frequency f of the test wave according to the test electrical signal, the signal generator 11 is configured to generate a detection wave with the frequency f, and then adjust the power supply 17, for example, adjust a voltage of the power supply 17 to be twice of a total voltage U of the battery pack 20, so that the detection wave with the frequency f is amplified by the power amplifier 15 to form a detection wave with the frequency f and the voltage of 2U, and the detection wave with the frequency f and the voltage of 2U may be input between the battery core 22 and the housing 21. Referring to fig. 3, wherein the voltage of the damped oscillatory wave is gradually decreased, the voltage 2U of the detection wave may refer to a maximum voltage value. T is the period of the detection wave, and f is 1/T.
Referring to fig. 1, in some embodiments, the detection electrical signal includes a pulse current, the insulation sampling circuit 13 includes a sampling chip 131, a first capacitor 137 and a second capacitor 139 that are serially connected, the sampling chip 131 is connected between the first capacitor 137 and the second capacitor 139, and the sampling chip 131 is configured to collect the pulse current generated when the detection wave passes through the battery pack 20 and determine that the battery pack 20 is partially discharged when the pulse current exists.
In some embodiments, the detection electrical signal comprises a pulse current, the insulation sampling circuit 13 comprises a sampling chip 131, a first capacitor 137 and a second capacitor 139 arranged in series, the sampling chip 131 is connected between the first capacitor 137 and the second capacitor 139, and the step 02 comprises:
024: the sampling chip 131 is used for collecting pulse current generated when the detection wave passes through the battery pack 20;
032: it is determined that partial discharge of the battery pack 20 occurs in the presence of the pulse current.
Therefore, a sampling circuit can be formed by the first capacitor 137 and the second capacitor 139, so that the pulse current generated when the detection wave passes through the battery pack 20 is acquired, and the test result is more accurate even if the battery pack 20 is only subjected to partial discharge through the detection mode of the pulse current.
Specifically, whether partial discharge occurs in the battery pack 20 is detected by a pulse current, wherein the partial discharge does not occur and the pulse current does not exist when the insulation performance of the battery pack 20 is good. When the insulation performance of the battery pack 20 is poor, partial discharge occurs, and a pulse current exists. Therefore, it can be determined that the partial discharge does not occur in the battery pack 20 when the pulse current does not exist, it can be determined that the insulation failure point or the insulation weak point does not exist in the battery pack 20, and the insulation performance of the battery pack 20 is good. When the pulse current exists, the partial discharge of the battery pack 20 can be determined, the insulation failure point or insulation weak point of the battery pack 20 can be determined, and the insulation performance of the battery pack 20 is poor.
Referring to fig. 1, in some embodiments, the detection electrical signal includes a response wave and a pulse current, the response wave is a damped oscillation wave generated when the detection wave passes through the battery pack 20, the insulation sampling circuit 13 includes a sampling chip 131, a first resistor 133, a second resistor 135, a first capacitor 137, and a second capacitor 139, which are connected in series, the sampling chip 131 is connected between the first resistor 133 and the second resistor 135, and between the first capacitor 137 and the second capacitor 139, and the sampling chip 131 is configured to collect a waveform and a frequency of the response wave and the pulse current generated when the detection wave passes through the battery pack 20, and determine whether the partial discharge occurs in the battery pack 20 according to the waveform and the frequency of the response wave and the pulse current.
In some embodiments, the detection electrical signal includes a response wave and a pulse current, the response wave is a damped oscillation wave generated when the detection wave passes through the battery pack 20, the insulation sampling circuit 13 includes a sampling chip 131, a first resistor 133 and a second resistor 135, which are arranged in series, a first capacitor 137 and a second capacitor 139, which are arranged in series, the sampling chip 131 is connected between the first resistor 133 and the second resistor 135, and between the first capacitor 137 and the second capacitor 139, and the step 02 includes:
026: the sampling chip 131 is used for collecting the waveform and frequency of the response wave and the pulse current generated when the detection wave passes through the battery pack 20;
034: whether the partial discharge of the battery pack 20 has occurred is determined based on the waveform and frequency of the response wave and the pulse current.
In this way, the first resistor 133, the second resistor 135, the first capacitor 137 and the second capacitor 139 may constitute a sampling circuit, so as to acquire and obtain the waveform and frequency of the response wave and the pulse current generated when the detection wave passes through the battery pack 20, and thus, whether the partial discharge occurs in the battery pack 20 may be determined according to the waveform and frequency of the response wave and the pulse current.
Specifically, when a detection wave is input between the battery cell 22 and the case 21, the battery pack 20 is affected by the detection wave, and a response wave is generated. Through the first resistor 133 and the second resistor 135 which are arranged in series, the sampling chip 131 can collect the response wave, so that the amplitude, the phase and the frequency of the response wave can be obtained through calculation, wherein the amplitude and the phase of the response wave can be used for characterizing the waveform of the response wave. The sampling chip 131 can collect the pulse current through the first capacitor 137 and the second capacitor 139 which are arranged in series, and can determine whether the partial discharge of the battery pack 20 occurs or not through the amplitude, the phase and the frequency of the response wave and the pulse current, and can further determine the position where the partial discharge occurs. Specifically, in one embodiment, the amplitude, phase, and frequency of the response wave and the change rule of the pulse current when the partial discharge occurs in each place of the battery pack 20 may be calibrated in advance, so that the position where the partial discharge occurs may be determined according to the pre-calibration information, the currently obtained amplitude, phase, and frequency of the response wave and the change rule of the pulse current, and thus the insulation failure point or the insulation weak point of the battery pack 20 may be identified in advance.
Referring to fig. 4, a response wave can be collected through the first resistor 133 and the second resistor 135, and the response wave is shown in the upper graph of fig. 4, where the horizontal axis is time in ms and the vertical axis is voltage in kv. The pulse current can be detected by the first capacitor 137 and the second capacitor 139, and is shown in the lower graph of fig. 4, where the horizontal axis is time in ms and the vertical axis is partial discharge capacity (PD level) in picocoulombs (pC). Wherein the lower graph of fig. 4 is substantially wave-free in the absence of a pulse current.
Referring to fig. 1, in some embodiments, the battery pack 20 includes a main positive relay 23 connected to the positive pole of the battery cell 22 and a main negative relay 24 connected to the negative pole of the battery cell 22, the main positive relay 23 is output through a main positive cable 26, the main negative relay is output through a main negative cable 27, and the detection wave is input between the main positive cable 26 and the casing 21 or the detection wave is input between the main negative cable 27 and the casing 21.
In this manner, by inputting the detection wave between the main positive cable 26 and the case 21 or between the main negative cable 27 and the case 21, the insulation failure point or the insulation weak point of the battery pack 20 can be broken down, thereby enabling insulation detection. In the example of fig. 1, the detection wave is used to be input between the overall negative cable 27 and the housing 21.
In some embodiments, the detection wave is used to be input between a middle point of the battery cell 22 and the casing 21, where the battery cell 22 may include a plurality of battery cells, and the middle point of the battery cell 22 refers to a point between any two battery cells 22.
Referring to fig. 1, in some embodiments, the signal generator 11 is configured to generate a plurality of detection waves; the insulation sampling circuit 13 is configured to collect a plurality of detection electrical signals generated when the detection wave passes through the battery pack 20 for a plurality of times, and determine whether the battery pack 20 has been partially discharged according to the plurality of detection electrical signals.
In certain embodiments, step 01 comprises:
014: generating a plurality of detection waves;
028: collecting a plurality of detection electric signals generated when a plurality of detection waves pass through the battery pack 20;
036: it is determined whether partial discharge of the battery pack 20 has occurred based on the plurality of detection electric signals.
Therefore, errors can be reduced through multiple detection, and false identification is avoided.
Specifically, the number of times may be any number of times, and in the embodiment of the present application, the number of times may be 50 times. The multiple detection waves may be continuously input between the battery cell 22 and the casing 21, that is, after the previous detection wave is input, the next detection wave may be continuously input. In some embodiments, a plurality of detection electrical signals may be screened, for example, if the middle detection electrical signal is stable, the first detection electrical signal and the second detection electrical signal may be removed, and whether the partial discharge of the battery pack 20 occurs may be determined according to the middle detection electrical signal. In some embodiments, it may be determined whether the battery pack 20 has been partially discharged according to the plurality of detection electrical signals, the number of detection electrical signals in which the battery pack 20 has been partially discharged is statistically determined, and the partial discharge of the battery pack 20 is determined when the ratio is greater than a preset ratio according to a ratio of the number of detection electrical signals in which the battery pack 20 has been partially discharged to the total number.
Referring to fig. 1, in some embodiments, the battery pack 20 includes a Battery Management System (BMS)28, the insulation sampling circuit 13 is integrated in the BMS 28, or the insulation sampling circuit 13 is provided separately from the battery pack 20. When the insulated sampling circuit 13 is disposed independently of the battery pack 20, the insulated sampling circuit 13 may be combined with the signal generator 11, the power amplifier 15, the power supply 17, and the like to form a dedicated system.
In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, various embodiments or examples and features of different embodiments or examples described in this specification can be combined and combined by one skilled in the art without contradiction.
Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "a plurality" means at least two, e.g., two, three, etc., unless specifically limited otherwise.
Any process or method descriptions in flow charts or otherwise described herein may be understood as representing modules, segments, or portions of code which include one or more executable instructions for implementing specific logical functions or steps of the process, and alternate implementations are included within the scope of the preferred embodiment of the present invention in which functions may be executed out of order from that shown or discussed, including substantially concurrently or in reverse order, depending on the functionality involved, as would be understood by those reasonably skilled in the art of the present invention.
Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention, and that variations, modifications, substitutions and alterations can be made to the above embodiments by those of ordinary skill in the art within the scope of the present invention.
Claims (10)
1. An insulation test device for testing a battery pack, the battery pack comprising a housing and a cell disposed within the housing, the insulation test device comprising:
a signal generator for generating a damped oscillation wave as a detection wave for input between the battery cell and the case;
and the insulation sampling circuit is used for acquiring a detection electric signal generated when the detection wave passes through the battery pack and determining whether the battery pack is partially discharged or not according to the detection electric signal.
2. The insulation testing device of claim 1, wherein the battery pack comprises a main positive relay connected to the positive electrode of the battery cell and a main negative relay connected to the negative electrode of the battery cell, the main positive relay and the main negative relay generate a damped oscillation wave as a test wave when being closed, the insulation sampling circuit is further configured to collect a test electrical signal corresponding to the test wave and determine the frequency of the test wave according to the test electrical signal when the signal generator is disconnected, the signal generator is configured to generate the detection wave according to the frequency of the test wave, and the frequency of the detection wave is the same as the frequency of the test wave.
3. The insulation testing device of claim 2, wherein the insulation sampling circuit comprises a sampling chip, a first resistor and a second resistor which are arranged in series, the sampling chip is connected between the first resistor and the second resistor, and the sampling chip is used for collecting the frequency of the test waves.
4. The insulation test apparatus as recited in claim 1, further comprising a power amplifier and a power supply, the power supply being configured to supply power to the power amplifier, the power amplifier being configured to amplify the detection wave output by the signal generator.
5. The insulation test device of claim 1, wherein the detection electrical signal comprises a pulse current, the insulation sampling circuit comprises a sampling chip, a first capacitor and a second capacitor arranged in series, the sampling chip is connected between the first capacitor and the second capacitor, and the sampling chip is configured to collect the pulse current generated when the detection wave passes through the battery pack and determine that the battery pack has been partially discharged when the pulse current is present.
6. The insulation test device of claim 1, wherein the detection electrical signal comprises a response wave and a pulse current, the response wave is a damped oscillation wave generated when the detection wave passes through the battery pack, the insulation sampling circuit comprises a sampling chip, a first resistor and a second resistor arranged in series, and a first capacitor and a second capacitor arranged in series, the sampling chip is connected between the first resistor and the second resistor and between the first capacitor and the second capacitor, and the sampling chip is used for collecting the waveform and frequency of the response wave and the pulse current generated when the detection wave passes through the battery pack and determining whether the partial discharge of the battery pack occurs according to the waveform and frequency of the response wave and the pulse current.
7. The insulation test apparatus of claim 1, wherein the battery pack comprises a main positive relay connected to the positive electrode of the cell and a main negative relay connected to the negative electrode of the cell, the main positive relay is output through a total positive cable, the total negative relay is output through a total negative cable, and the detection wave is input between the total positive cable and the housing or the detection wave is input between the total negative cable and the housing.
8. The insulation test apparatus of claim 1, wherein the signal generator is configured to generate the detection wave a plurality of times; the insulation sampling circuit is used for collecting a plurality of detection electric signals generated when the detection waves pass through the battery pack for a plurality of times, and determining whether the battery pack is partially discharged or not according to the plurality of detection electric signals.
9. The insulation test apparatus of claim 1, wherein the battery pack comprises a battery management system, the insulation sampling circuit is integrated in the battery management system, or the insulation sampling circuit is provided separately from the battery pack.
10. An insulation test method for testing a battery pack, wherein the battery pack comprises a housing and a battery cell arranged in the housing, the insulation test method comprising:
generating a damped oscillation wave as a detection wave and inputting the detection wave between the battery cell and the casing;
collecting a detection electric signal generated when the detection wave passes through the battery pack;
and determining whether the partial discharge of the battery pack occurs according to the detection electric signal.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210476377.9A CN114878984A (en) | 2022-04-29 | 2022-04-29 | Insulation test device and insulation test method |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210476377.9A CN114878984A (en) | 2022-04-29 | 2022-04-29 | Insulation test device and insulation test method |
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| CN202210476377.9A Pending CN114878984A (en) | 2022-04-29 | 2022-04-29 | Insulation test device and insulation test method |
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| CN (1) | CN114878984A (en) |
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