Insulation testing device, insulation testing method

Abstract

The present invention discloses an insulation testing device and an insulation testing method. The insulation testing device is used to test a battery pack, and the battery pack includes a housing and battery cells disposed within the housing. The insulation testing device includes a signal generator and an insulation sampling circuit. The signal generator is used to generate a damped oscillation wave as a detection wave, and the detection wave is input between the battery cells and the housing. The insulation sampling circuit is used to collect the detection electrical signal generated when the detection wave passes through the battery pack, and determine whether partial discharge occurs in the battery pack according to the detection electrical signal. In the above insulation testing device and insulation testing method, a damped oscillation wave can be input into the battery pack as a detection wave, and it can be determined whether partial discharge occurs in the battery pack according to the detection electrical signal generated when the detection wave passes through the battery pack, so as to realize the insulation performance test of the battery pack. Among them, when partial discharge occurs in the battery pack, it can be considered that there is an insulation failure point or an insulation weak point in the battery pack.

Description

Technical Field

[0001] The present invention relates to battery insulation testing technology, and particularly to an insulation testing device and an insulation testing method. Background Art

[0002] In scenarios where battery packs are used (such as new energy vehicles), the safety of the battery pack is of utmost importance, and the insulation performance of the battery pack is an important performance for its safety. In related technologies, for the safe use of the battery pack, it is necessary to test the insulation performance of the battery pack. Summary of the Invention

[0003] The present invention provides an insulation testing device and an insulation testing method.

[0004] The insulation testing device of the present invention can be used to test a battery pack, which includes a housing and battery cells disposed within the housing. The insulation testing device includes a signal generator and an insulation sampling circuit. The signal generator is used to generate a damped oscillation wave as a detection wave, and the detection wave is input between the battery cells and the housing. The insulation sampling circuit is used to collect the detection electrical signal generated when the detection wave passes through the battery pack, and determine whether partial discharge occurs in the battery pack according to the detection electrical signal.

[0005] 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. When the main positive relay and the main negative relay are closed, a damped oscillation wave is generated as a test wave. When the signal generator is disconnected, the insulation sampling circuit is further used to collect the test electrical signal corresponding to the test wave, and determine the frequency of the test wave according to the test electrical signal. The signal generator is used to generate the detection wave according to the frequency of the test wave, and the frequency of the detection wave is the same as that of the test wave.

[0006] In some embodiments, the insulation sampling circuit includes a sampling chip, a first resistor and a second resistor connected in series. The sampling chip is connected between the first resistor and the second resistor, and the sampling chip is used to collect the frequency of the test wave.

[0007] In some embodiments, the insulation testing device further includes a power amplifier and a power supply. The power supply is used to supply power to the power amplifier, and the power amplifier is used to amplify the detection wave output by the signal generator.

[0008] In some embodiments, the detected electrical signal includes a pulsed current, and the insulation sampling circuit includes a sampling chip, a first capacitor and a second capacitor connected in series. The sampling chip is connected between the first capacitor and the second capacitor. The sampling chip is configured to collect the pulsed current generated when the detection wave passes through the battery pack, and determine that partial discharge has occurred in the battery pack when the pulsed current exists.

[0009] In some embodiments, the detected electrical signal includes a response wave and a pulsed 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 connected in series, and a first capacitor and a second capacitor connected 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 the waveform and frequency of the response wave, and the pulsed current generated when the detection wave passes through the battery pack, and determine whether partial discharge has occurred in the battery pack based on the waveform and frequency of the response wave and the pulsed current.

[0010] 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 outputs through a total positive cable, and the main negative relay outputs through a total negative cable. The detection wave is configured to be input between the total positive cable and the housing, or the detection wave is configured to be input between the total negative cable and the housing.

[0011] In some embodiments, the signal generator is configured to generate multiple detection waves; the insulation sampling circuit is configured to collect multiple detected electrical signals generated when the multiple detection waves pass through the battery pack, and determine whether partial discharge has occurred in the battery pack based on the multiple detected electrical signals.

[0012] 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 independently of the battery pack.

[0013] The insulation test method of the present invention can be used to test a battery pack. The battery pack includes a housing and battery cells disposed in the housing. The insulation test method includes: generating a damped oscillation wave as a detection wave and inputting the detection wave between the battery cells and the housing; collecting a detected electrical signal generated when the detection wave passes through the battery pack; and determining whether partial discharge has occurred in the battery pack based on the detected electrical signal.

[0014] In the above insulation testing device and insulation testing method, a damped oscillatory wave is input into the battery pack as a detection wave, and whether partial discharge occurs in the battery pack can be determined according to the detection electrical signal generated when the detection wave passes through the battery pack, so as to realize the insulation performance test of the battery pack. Among them, when partial discharge occurs in the battery pack, it can be considered that there are insulation failure points or insulation weak points in the battery pack.

[0015] Additional aspects and advantages of the present invention will be given in part in the following description, become apparent in part from the following description, or be learned through the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The above and / or additional aspects and advantages of the present invention will become apparent and be readily understood from the following description of embodiments in conjunction with the accompanying drawings, in which:

[0017] Figure 1 is a schematic connection diagram of the insulation testing device of the present invention and the battery pack;

[0018] Figure 2 is a schematic flow diagram of the insulation testing method of the present invention.

[0019] Figure 3 is a schematic diagram of the detection wave of the present invention.

[0020] Figure 4 is a schematic diagram of the response wave and pulse current of the present invention.

[0021] MAIN ELEMENT SYMBOL DESCRIPTION:

[0022] Insulation testing device 10, signal generator 11, insulation sampling circuit 13, sampling chip 131, first resistor 133, second resistor 135, first capacitor 137, second capacitor 139, power amplifier 15, power supply 17, battery pack 20, housing 21, battery cell 22, main positive relay 23, main negative relay 24, connecting member 25, total positive cable 26, total negative cable 27, battery management system 28. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0023] Embodiments of the present invention will be described in detail below. Examples of the embodiments are shown in the accompanying drawings, where the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the accompanying drawings are exemplary and are intended to explain the present invention, and should not be construed as limiting the present invention.

[0024] In scenarios where battery packs are used (such as new energy vehicles), the safety of battery packs is crucial, and the insulation performance of battery packs is an important performance for battery pack safety. In related technologies, in order to ensure the safe use of battery packs, insulation performance tests need to be carried out on battery packs.

[0025] In the related art, the insulation performance test of the battery pack mainly includes DC withstand voltage test and AC withstand voltage test. The DC withstand voltage test has the following several defects. First, the DC withstand voltage test cannot test partial discharge. Second, the DC withstand voltage test will damage the insulation performance of the battery pack. After the high voltage of the DC withstand voltage test is removed, the insulation layer will still maintain the molecular arrangement in the polarized state for a certain period, and its molecular arrangement is not easy to return to the state before the application of the DC high voltage. The AC withstand voltage test generally uses the power frequency 50Hz AC withstand voltage test. Although the damage to the battery pack is slightly smaller, it generally can only break down relatively serious defects. For less serious defects, it may be excited and developed (making the defects easier to break down), and it may not necessarily be able to break down. Moreover, due to the difference in the equivalent inductance and equivalent capacitance of the battery pack, the resonance frequency of the high-voltage circuit of each battery pack is inconsistent. Simply using the power frequency 50Hz test cannot simulate the actual working conditions of the battery pack.

[0026] Please refer to Figure 1 , the insulation test device 10 of the present invention can be used to test the battery pack 20. The battery pack 20 includes a housing 21 and battery cells 22 disposed within the housing 21. The insulation test device 10 includes a signal generator 11 and an insulation sampling circuit 13. The signal generator 11 is used to generate a damped oscillation wave as a detection wave, and the detection wave is input between the battery cells 22 and the housing 21. The insulation sampling circuit 13 is used to collect the detection electrical signals generated when the detection wave passes through the battery pack 20, and determine whether partial discharge occurs in the battery pack 20 according to the detection electrical signals.

[0027] Please refer to Figure 1 and Figure 2 , the insulation test method of the present invention can be used to test the battery pack 20. The battery pack 20 includes a housing 21 and battery cells 22 disposed within the housing 21. The insulation test method includes:

[0028] 01: Generate a damped oscillation wave as a detection wave and input the detection wave between the battery cells 22 and the housing 21;

[0029] 02: Collect the detection electrical signals generated when the detection wave passes through the battery pack 20;

[0030] 03: Determine whether partial discharge occurs in the battery pack 20 according to the detection electrical signals.

[0031] The insulation test method of the present application can be implemented by the insulation test device 10 of the present application. Among them, step 01 can be implemented by the signal generator 11, and steps 02 and 03 can be implemented by the insulation sampling circuit 13.

[0032] In the above-mentioned insulation testing device 10 and insulation testing method, a damped oscillating wave is input into the battery pack 20 as a detection wave. According to the detection electrical signal generated when the detection wave passes through the battery pack 20, it can be determined whether partial discharge has occurred in the battery pack 20, thereby realizing the insulation performance test of the battery pack 20. Among them, when partial discharge occurs in the battery pack 20, it can be considered that there are insulation failure points or insulation weak points in the battery pack 20.

[0033] In some embodiments, the battery pack 20 can be a power battery of a new energy vehicle.

[0034] Please refer to Figure 3 , the damped oscillating wave can refer to an electrical signal whose amplitude gradually decays with time, where the horizontal axis is time and the vertical axis is voltage. The signal generator 11 can be any circuit capable of generating a damped oscillating wave. For example, the signal generator can be components such as a CPU or an MCU connected to a preset output circuit, and the CPU or MCU can output a damped oscillating wave through the preset output circuit.

[0035] The damped oscillating wave is input as a detection wave between the battery cell 22 and the housing 21, and the housing 21 is connected to the ground. Due to the different insulation performances of the battery pack 20, different detection electrical signals can be generated after the detection wave passes through the battery pack 20. Therefore, according to the detection electrical signal, it can be determined whether partial discharge has occurred in the battery pack 20, thereby determining the insulation performance of the battery pack 20.

[0036] In some embodiments, the insulation sampling circuit 13 has a processing function and can process the detection electrical signal to determine whether partial discharge has occurred in the battery pack 20. In some embodiments, if the insulation sampling circuit 13 does not have a processing function, the insulation sampling circuit 13 can send the detection electrical signal to a processing element for processing to determine whether partial discharge has occurred in the battery pack 20.

[0037] In the above-mentioned insulation testing device 10 and insulation testing method, the insulation test can be carried out before the battery pack 20 is shipped. When partial discharge occurs in the battery pack 20, it can be determined that there are insulation failure points or insulation weak points in the battery pack 20. Therefore, it can be determined that the insulation performance of the battery pack 20 is poor and the battery pack 20 cannot be shipped; when no partial discharge occurs in the battery pack 20, it can be determined that there are no insulation failure points or insulation weak points in the battery pack 20. Therefore, it can be determined that the insulation performance of the battery pack 20 is good and the battery pack 20 can be shipped normally.

[0038] The present invention uses a damped oscillating wave as a detection for insulation performance detection, so it will not damage the insulation performance of the battery pack 20. However, the DC withstand voltage test will cause damage to the insulation performance of the battery pack. For a period of time after the high voltage of the DC withstand voltage test is removed, the insulation layer will still maintain the molecular arrangement in the polarized state, and its molecular arrangement is not easy to return to the state before the DC high voltage is applied.

[0039] Please refer to Figure 1 Figure 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. When the main positive relay 23 and the main negative relay 24 are closed, a damped oscillation wave is generated as a test wave. When the signal generator 11 is disconnected, the insulation sampling circuit 13 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. The signal generator 11 is configured to generate a 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.

[0040] 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 insulation test method further includes:

[0041] 04: Disconnect the signal generator 11;

[0042] 05: Close the main positive relay 23 and the main negative relay 24 to generate a damped oscillation wave as a test wave;

[0043] 06: Collect a test electrical signal corresponding to the test wave and determine the frequency of the test wave according to the test electrical signal;

[0044] Step 01 includes:

[0045] 012: Generate a 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.

[0046] Specifically, the battery pack 20 further includes a connecting member 25, such as 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, and the negative electrode of the battery cell 22 is connected to the main negative relay 24 through the high-voltage copper bar. There may be insulation failure points or insulation weak points in the battery cell 22, copper bar, wire harness, etc. due to design or manufacturing processes. There may be partial discharge or short circuit under the high voltage of the battery cell 22.

[0047] When the main positive relay 23 and the main negative relay 24 are closed, since the voltage difference across the front and rear ends of the relay contacts before closing the relay is very large, the voltage across the front and rear ends of the contacts will become the same after the relay is closed. Due to the steep wavefront time (the time from the start to the maximum voltage value) of the instantaneous voltage change reaching the order of dozens of nanoseconds, when propagating on the high-voltage circuit, this steep wave phenomenon will be mitigated by the capacitance formed by all the high-voltage components in the battery pack 20. Therefore, a damped oscillatory wave (test wave) will be formed in the high-voltage circuit. The frequency of the test wave is related to parameters such as the parasitic inductance and parasitic capacitance of the battery pack 20. So, there will be a certain difference in the frequency of the test wave for each battery pack 20. Before closing the main positive relay 23 and the main negative relay 24, the signal generator 11 is first disconnected to avoid the detection wave generated by the signal generator 11 affecting the acquisition of the test wave.

[0048] Detect the frequency f of the test wave, and then generate a damped oscillatory wave with a frequency of f as the detection wave through the signal generator 11. Then, the detection wave can be input between the battery cell 22 and the housing 21. The frequency of the detection wave of the present invention varies according to each battery pack. Using the frequency of the test wave as the frequency of the detection wave, the frequency of the test wave is the natural resonance frequency of the battery pack 20 and can better represent the working condition of the battery pack 20. Therefore, the detection wave can better detect the insulation performance of the battery pack 20.

[0049] When the insulation sampling circuit 13 samples the detection electrical signal, the main positive relay 23 and the main negative relay 24 are closed.

[0050] Please refer to Figure 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 to collect the frequency of the test wave.

[0051] 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. Step 02 includes:

[0052] 022: Use the sampling chip 131 to collect the frequency of the test wave.

[0053] In this way, a sampling circuit can be formed by the first resistor 133 and the second resistor 135, so as to collect and obtain the information of the test wave.

[0054] Specifically, through the first resistor 133 and the second resistor 135 connected in series, the sampling chip 131 can collect the damped oscillation wave (test wave) generated when the main positive relay 23 and the main negative relay 24 are closed, and thus the frequency of the test wave can be calculated.

[0055] Please refer to Figure 1 , in some embodiments, the insulation testing device 10 further includes a power amplifier 15 and a power supply 17. The power supply 17 is used to supply power to the power amplifier 15, and the power amplifier 15 is used to amplify the detection wave output by the signal generator 11.

[0056] In some embodiments, the insulation testing device 10 further includes a power amplifier 15 and a power supply 17. The power supply 17 is used to supply power to the power amplifier 15. The insulation testing method further includes:

[0057] 07: Using the power amplifier 15 to amplify the detection wave output by the signal generator 11.

[0058] 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 housing 21. Among them, the amplified detection wave is more likely to break down the insulation failure point or the insulation weak point, so as to more accurately detect the insulation performance of the battery pack 20. The power supply 17 can 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.

[0059] 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 supply 17 is greater than the total voltage of the battery pack 20.

[0060] In this way, the amplified detection wave is more likely to break down the insulation failure point or the insulation weak point, so as to more accurately detect the insulation performance of the battery pack 20. Among them, 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 sufficient energy for the power amplifier 15, enabling the power amplifier 15 to 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 a preset voltage. In this way, it can be avoided that the amplified detection wave wrongly breaks 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.

[0061] In some embodiments, the insulation sampling circuit 13 is used to collect the test electrical signal corresponding to the test wave, and determine the frequency f of the test wave according to the test electrical signal. The signal generator 11 is used to generate a detection wave with a frequency of f, and then the power supply 17 is adjusted. For example, the voltage of the power supply 17 is adjusted to twice the total voltage U of the battery pack 20, so that the detection wave with a frequency of f forms a detection wave with a frequency of f and a voltage of 2U after being amplified by the power amplifier 15. The detection wave with a frequency of f and a voltage of 2U can be input between the battery cell 22 and the housing 21. Please refer to Figure 3 , where the voltage of the damped oscillation wave gradually decreases, and the voltage 2U of the detection wave may refer to the maximum voltage value. T is the period of the detection wave, and f = 1 / T.

[0062] Please refer to Figure 1 , in some embodiments, the test electrical signal includes a pulsed current. The insulation sampling circuit 13 includes a sampling chip 131, a first capacitor 137 and a second capacitor 139 connected in series. The sampling chip 131 is connected between the first capacitor 137 and the second capacitor 139. The sampling chip 131 is used to collect the pulsed current generated when the detection wave passes through the battery pack 20, and determine that the battery pack 20 has a partial discharge when there is a pulsed current.

[0063] In some embodiments, the test electrical signal includes a pulsed current. The insulation sampling circuit 13 includes a sampling chip 131, a first capacitor 137 and a second capacitor 139 connected in series. The sampling chip 131 is connected between the first capacitor 137 and the second capacitor 139. Step 02 includes:

[0064] 024: Use the sampling chip 131 to collect the pulsed current generated when the detection wave passes through the battery pack 20;

[0065] Step 03 includes:

[0066] 032: Determine that the battery pack 20 has a partial discharge when there is a pulsed current.

[0067] In this way, a sampling circuit can be formed by the first capacitor 137 and the second capacitor 139, so as to collect the pulsed current generated when the detection wave passes through the battery pack 20. Through the detection method of the pulsed current, even if only a partial discharge occurs in the battery pack 20, it can be detected, and the test result is more accurate.

[0068] Specifically, it is detected whether partial discharge occurs in the battery pack 20 through a pulsed current. Among them, when the insulation performance of the battery pack 20 is good, no partial discharge occurs and there is no pulsed current. When the insulation performance of the battery pack 20 is poor, partial discharge occurs and there is a pulsed current. Therefore, when there is no pulsed current, it can be determined that no partial discharge occurs in the battery pack 20, it can be determined that there is no insulation failure point or insulation weak point in the battery pack 20, and the insulation performance of the battery pack 20 is good. When there is a pulsed current, it can be determined that partial discharge occurs in the battery pack 20, it can be determined that there is an insulation failure point or insulation weak point in the battery pack 20, and the insulation performance of the battery pack 20 is poor.

[0069] Please refer to Figure 1 , in some embodiments, the detected electrical signal includes a response wave and a pulsed 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 connected in series, and a first capacitor 137 and a second capacitor 139 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. The sampling chip 131 is configured to collect the waveform and frequency of the response wave, and the pulsed current generated when the detection wave passes through the battery pack 20, and determine whether partial discharge occurs in the battery pack 20 according to the waveform and frequency of the response wave and the pulsed current.

[0070] In some embodiments, the detected electrical signal includes a response wave and a pulsed 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 connected in series, and a first capacitor 137 and a second capacitor 139 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. Step 02 includes:

[0071] 026: Use the sampling chip 131 to collect the waveform and frequency of the response wave, and the pulsed current generated when the detection wave passes through the battery pack 20;

[0072] Step 03 includes:

[0073] 034: Determine whether partial discharge occurs in the battery pack 20 according to the waveform and frequency of the response wave and the pulsed current.

[0074] In this way, a sampling circuit can be formed by the first resistor 133, the second resistor 135, the first capacitor 137 and the second capacitor 139, so as to collect the waveform and frequency of the response wave and the pulsed current generated when the detection wave passes through the battery pack 20, and thus it can be determined whether partial discharge occurs in the battery pack 20 according to the waveform and frequency of the response wave and the pulsed current.

[0075] Specifically, when a detection wave is input between the battery cell 22 and the housing 21, the battery pack 20 will be affected by the detection wave, thereby generating a response wave. Through the first resistor 133 and the second resistor 135 connected in series, the sampling chip 131 can collect the response wave, and thus the amplitude, phase, and frequency of the response wave can be calculated. Among them, the amplitude and phase of the response wave can be used to characterize the waveform of the response wave. Through the first capacitor 137 and the second capacitor 139 connected in series, the sampling chip 131 can collect the pulse current. Based on the amplitude, phase, and frequency of the response wave and the pulse current, it can be determined whether the battery pack 20 has partial discharge, and the location where the partial discharge occurs can be further determined. Specifically, in one embodiment, the variation laws of the amplitude, phase, and frequency of the response wave and the pulse current when partial discharge occurs at various locations of the battery pack 20 can be pre-calibrated. Thus, based on the pre-calibrated information and the variation laws of the amplitude, phase, and frequency of the currently obtained response wave and the pulse current, the location where the partial discharge occurs can be determined, and thus the insulation failure point or insulation weak point of the battery pack 20 can be identified in advance.

[0076] Please refer to Figure 4 , the response wave can be collected through the first resistor 133 and the second resistor 135. The response wave is as shown in the upper figure of Figure 4 . Among them, the horizontal axis is time, with the unit of ms, and the vertical axis is voltage, with the unit of kv. The pulse current can be collected through the first capacitor 137 and the second capacitor 139. The pulse current is as shown in the lower figure of Figure 4 . Among them, the horizontal axis is time, with the unit of ms, and the vertical axis is the partial discharge charge (PD level), with the unit of picocoulombs (pC). Among them, when there is no pulse current, Figure 4 the lower figure of

[0077] Please refer to Figure 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 outputs through the total positive cable 26, and the main negative relay outputs through the total negative cable 27. The detection wave is used to be input between the total positive cable 26 and the housing 21, or the detection wave is used to be input between the total negative cable 27 and the housing 21.

[0078] In this way, by inputting the detection wave between the total positive cable 26 and the housing 21, or by inputting the detection wave between the total negative cable 27 and the housing 21, the insulation failure point or insulation weak point of the battery pack 20 can be broken down, and thus insulation detection can be performed. In the Figure 1 example, the detection wave is used to be input between the total negative cable 27 and the housing 21.

[0079] In some embodiments, the detection wave is input between the middle point of the battery cell 22 and the housing 21. Wherein, there may be multiple battery cells 22, and the middle point of the battery cells 22 refers to the point between any two battery cells 22.

[0080] Please refer to Figure 1 , in some embodiments, the signal generator 11 is used to generate multiple detection waves; the insulation sampling circuit 13 is used to collect multiple detection electrical signals generated when the multiple detection waves pass through the battery pack 20, and determine whether partial discharge has occurred in the battery pack 20 according to the multiple detection electrical signals.

[0081] In some embodiments, step 01 includes:

[0082] 014: Generate multiple detection waves;

[0083] Step 02 includes:

[0084] 028: Collect multiple detection electrical signals generated when the multiple detection waves pass through the battery pack 20;

[0085] Step 03 includes:

[0086] 036: Determine whether partial discharge has occurred in the battery pack 20 according to the multiple detection electrical signals.

[0087] In this way, multiple detections can reduce errors and avoid misidentification.

[0088] Specifically, multiple times can be any number of times. In the embodiments of the present application, multiple times can be 50 times. Among them, the multiple detection waves can be continuously input between the battery cell 22 and the housing 21. That is to say, after the previous detection wave is input, the next detection wave can be continuously input. In some embodiments, multiple detection electrical signals can be screened. For example, if the middle detection electrical signals are relatively stable, the previous few detection electrical signals and the subsequent few detection electrical signals can be removed, and it is determined whether partial discharge has occurred in the battery pack 20 according to the middle detection electrical signals. In some embodiments, it can be determined whether partial discharge has occurred in the battery pack 20 according to multiple detection electrical signals respectively, the number of detection electrical signals determined to have partial discharge in the battery pack 20 is counted, and according to the ratio of the number of detection electrical signals determined to have partial discharge in the battery pack 20 to the total number, it is determined that partial discharge has occurred in the battery pack 20 when the ratio is greater than the preset ratio.

[0089] Please refer to Figure 1, in some embodiments, the battery pack 20 includes a battery management system (BMS) 28. The insulation sampling circuit 13 is integrated in the battery management system 28 or is provided independently of the battery pack 20. When the insulation sampling circuit 13 is provided independently of the battery pack 20, the insulation sampling circuit 13 can be placed together with the signal generator 11, the power amplifier 15, the power supply 17, etc. to form a dedicated system.

[0090] In the description of this specification, the descriptions with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples", etc. mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples.

[0091] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0092] Any process or method description shown in the flowchart or described in other ways herein can be understood as representing a module, segment, or part of the code including one or more executable instructions for implementing a specific logical function or process. The scope of the preferred embodiments of the present invention includes additional implementations, where the functions can be executed in a substantially simultaneous manner or in a reverse order according to the functions involved, rather than in the order shown or discussed, which should be understood by those skilled in the art to which the embodiments of the present invention belong.

[0093] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limiting the present invention. Those of ordinary skill in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present invention.

Claims

1. An insulation testing device for testing a battery pack, characterized in that, The battery pack includes a housing and battery cells disposed within the housing. The insulation testing device includes: A signal generator configured to generate a damped oscillatory wave as a detection wave, which is input between the battery cells and the housing; An insulation sampling circuit configured to collect a detection electrical signal generated when the detection wave passes through the battery pack, and determine whether partial discharge has occurred in the battery pack based on the detection electrical signal; 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. When the signal generator is disconnected and the main positive relay and the main negative relay are closed, a damped oscillatory wave is generated as a test wave, and the frequency of the test wave is the natural resonance frequency of the battery pack. The frequency of the detection wave is the same as the frequency of the test wave.

2. The insulation testing device according to claim 1, wherein When the signal generator is disconnected, 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 based on the test electrical signal. The signal generator is configured to generate the detection wave based on the frequency of the test wave.

3. The insulation testing device according to claim 2, wherein, The insulation sampling circuit includes a sampling chip, a first resistor and a second resistor connected in series. The sampling chip is connected between the first resistor and the second resistor, and the sampling chip is configured to collect the frequency of the test wave.

4. The insulation testing device according to claim 1, wherein, The insulation testing device further includes a power amplifier and a power supply. The power supply is configured to supply power to the power amplifier, and the power amplifier is configured to amplify the detection wave output by the signal generator.

5. The insulation testing device according to claim 1, wherein The detection electrical signal includes a pulse current. The insulation sampling circuit includes a sampling chip, a first capacitor and a second capacitor 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 has occurred in the battery pack when there is the pulse current.

6. The insulation testing device according to claim 1, characterized in that The detection electrical signal includes a response wave and a pulse current. The response wave is a damped oscillatory 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 connected in series, and a first capacitor and a second capacitor connected 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 the waveform and frequency of the response wave, and the pulse current generated when the detection wave passes through the battery pack, and determine whether partial discharge has occurred in the battery pack based on the waveform and frequency of the response wave and the pulse current.

7. The insulation testing device according to claim 1, characterized in that 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 is output through a main positive cable, and the main negative relay is output through a main negative cable. The detection wave is input between the main positive cable and the housing, or the detection wave is input between the main negative cable and the housing.

8. The insulation testing device according to claim 1, characterized in that, The signal generator is used to generate the detection wave multiple times; the insulation sampling circuit is used to collect multiple detection electrical signals generated when the detection wave passes through the battery pack multiple times, and determine whether partial discharge has occurred in the battery pack according to the multiple detection electrical signals.

9. The insulation testing device according to claim 1, characterized in that The battery pack includes a battery management system, and the insulation sampling circuit is integrated in the battery management system or is provided independently of the battery pack.

10. An insulation testing method for testing a battery pack, characterized in that, The battery pack includes a housing and battery cells disposed in the housing, and the insulation testing method includes: Generating a damped oscillation wave as the detection wave and inputting the detection wave between the battery cell and the housing. Collecting the detection electrical signal generated when the detection wave passes through the battery pack. Determining whether partial discharge has occurred in the battery pack according to the detection electrical signal. Wherein 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. When the signal generator is disconnected and the main positive relay and the main negative relay are closed, a damped oscillation wave is generated as the test wave, the frequency of the test wave is the natural resonance frequency of the battery pack, and the frequency of the detection wave is the same as the frequency of the test wave.

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