A high-voltage connector assembly device for new energy vehicle power distribution

Abstract

This invention relates to the field of power distribution technology for new energy vehicles, and particularly to a high-voltage connector assembly for power distribution in new energy vehicles, comprising a conductive connection mechanism, a clamp, and a sampling circuit; a data acquisition module for real-time acquisition of charging current timing sequence and bus voltage high-frequency sampling sequence; a silver plating wear analysis module for determining the wear state of the silver plating layer based on current fluctuations and voltage fluctuations at the same frequency; a micro-arc state analysis module for determining the micro-arc state based on voltage spike characteristics; and a contact resistance deterioration assessment module for determining the dynamic contact resistance rise rate based on charging current and bus voltage to determine the contact resistance deterioration state and output a warning signal. This invention solves the technical problem that current fluctuations and interlayer resonant coupling between soft copper busbars during DC fast charging lead to silver plating wear and trigger oxide film breakdown micro-arcs, thereby causing dynamic deterioration of contact resistance.

Description

Technical Field

[0001] This invention relates to the field of new energy vehicle power distribution technology, and in particular to a high-voltage connector assembly for new energy vehicle power distribution. Background Technology

[0002] In current high-voltage power distribution systems for new energy electric vehicles, junction boxes are commonly used to distribute current between high-voltage components such as battery packs and motor controllers. Traditional junction boxes often employ exposed terminals, rigid copper busbar splicing, or simple plastic housing structures, which suffer from defects such as weak current carrying capacity, high contact resistance, high temperature rise, and susceptibility to ablation. Furthermore, the lack of effective insulation for conductive components easily leads to safety hazards such as short circuits, creepage, and arcing. On the other hand, during DC fast charging, the current output by the charging pile is not ideal DC but contains fluctuation components of a specific frequency. When the fluctuation frequency approaches the inherent resonant frequency between the layers of the silver-plated soft copper busbar inside the junction box, it can excite micron-level high-frequency sliding between the copper busbar layers, causing wear or even penetration of the silver plating. An oxide film rapidly forms on the exposed copper substrate surface, and under repeated excitation by the fluctuating current, an oxide film breakdown micro-arc occurs, causing dynamic deterioration of contact resistance, abnormal local temperature rise, and in severe cases, arcing and ablation.

[0003] Existing technologies only focus on the static protection capabilities of junction boxes, lacking online monitoring methods for the cumulative damage caused by charging current fluctuations and coupling with the soft copper busbar structure. They cannot provide timely warnings in the early stages of silver plating wear or the occurrence of micro-arcs, resulting in unpredictable connector lifespan and potential safety hazards.

[0004] Chinese Patent Publication No. CN118393268A discloses a method and system for monitoring the operation of a high-voltage connector, belonging to the field of high-voltage connector technology. The method includes: acquiring an analog signal source using a data acquisition device; normalizing the acquired analog signal source to generate a controllable signal source; setting a dynamic terminating resistor; establishing a first test model, outputting test results, calculating the difference, and outputting the calculation result; setting a difference threshold, comparing the difference threshold with the difference calculation result, and issuing an early warning based on the comparison result. In the implementation of this application's technical solution, an analog signal source is acquired using a data acquisition device, and the analog signal source is normalized to generate a controllable signal source. This controllable signal source is used as the input signal in the test process. A dynamic terminating resistor, controlled by the maximum amplitude of the controllable signal source, is set to dynamically adjust the resistance value of the terminating resistor. An early warning is issued based on the test results, thus achieving monitoring of the high-voltage connector's operation.

[0005] However, the aforementioned high-voltage connector operation monitoring method and system have the following problems: This scheme indirectly monitors the electromagnetic shielding performance of high-voltage connectors by using an external analog signal source and dynamic terminating resistors, but it cannot directly sense the conductive contact state of the connector itself. Its shortcomings are: it uses an open-loop detection method with an external excitation signal, failing to utilize the existing current and voltage signals during charging, and it fails to identify the hidden failure mechanism of silver plating wear caused by specific frequency fluctuations in charging current and resonant coupling between soft copper busbar layers. It only outputs a single-layer warning signal, making it difficult to quantify the dynamic deterioration of contact resistance. Summary of the Invention

[0006] To address this issue, the present invention provides a high-voltage connector assembly for power distribution in new energy vehicles, which overcomes the problem in the prior art where specific frequency fluctuations of the charging current during DC fast charging excite interlayer resonance in the soft copper busbar, leading to wear of the silver plating layer and generation of oxide film breakdown micro-arcs, thereby causing dynamic deterioration of contact resistance.

[0007] To achieve the above objectives, the present invention provides a high-voltage connector assembly for on-board power distribution in new energy vehicles, comprising a connector housing, characterized in that it further comprises, A conductive connection mechanism is disposed inside and on the side of the connector housing to enable the conduction of high voltage and high current. The sampling circuit includes a current sampling circuit for acquiring the timing sequence of the charging current flowing from the DC charging socket through the fast charging main relay into the junction box's positive input busbar, and a voltage sampling circuit for acquiring the high-frequency sampling sequence of the bus voltages flowing from the DC charging socket through the fast charging main relay into the junction box's positive and negative input busbars. The data acquisition module is used to acquire the charging current timing sequence and the bus voltage high-frequency sampling sequence in real time. The silver plating wear analysis module is used to determine the equivalent contact resistance fluctuation rate of the circuit where the positive input busbar and the negative input busbar are located based on the current fluctuation characteristics in the charging current time sequence and the same frequency voltage fluctuation characteristics in the high frequency sampling sequence of the busbar voltage, so as to determine the wear state of the silver plating layer at the electrical contact interface between the positive input busbar and the negative input busbar. The micro-arc state analysis module is used to determine the micro-arc pulse frequency based on the voltage spike characteristics in the high-frequency sampling sequence of the bus voltage, and to determine the micro-arc state of the electrical contact interface based on the changing trend of the micro-arc pulse frequency. The contact resistance deterioration early warning module is used to determine the rate of increase of the equivalent contact resistance of the circuit containing the positive input busbar and the negative input busbar based on the charging current timing sequence and the high-frequency sampling sequence of the bus voltage, and to determine the deterioration state of the contact resistance based on the trend of the rate of increase, and output an early warning signal.

[0008] Furthermore, the conductive connection mechanism includes, A soft copper busbar assembly includes a positive input busbar and a negative input busbar disposed on one side of a metal housing and connected to a plastic body, for conducting high voltage and high current; A copper busbar sleeve is fitted over the opening between the flexible copper busbar assembly and the metal housing to achieve a radial seal at the opening between the flexible copper busbar assembly and the metal housing. Terminal assembly, which is disposed inside the metal housing.

[0009] Furthermore, mounting holes are provided at both ends of the positive input busbar and the negative input busbar for connection to the terminal assembly.

[0010] Furthermore, the silver plating wear analysis module includes, The resistance fluctuation rate determination unit is used to determine the contact resistance fluctuation rate based on the ratio of the dynamic contact resistance fluctuation amplitude to the static contact resistance, in order to determine the relative fluctuation of contact resistance caused by the wear of the silver plating layer. Static contact resistance is determined based on the steady-state voltage drop and current between the positive input busbar and the negative input busbar in an unworn state under rated DC current. The amplitude of dynamic contact resistance fluctuation is determined based on the amplitude of voltage fluctuation and current fluctuation at the same frequency. The larger the fluctuation amplitude, the more intense the dynamic response of the electrical contact interface under the excitation of fluctuating current, and the more severe the wear of the silver plating layer. The amplitude of voltage fluctuation at the same frequency is determined based on the high-frequency sampling sequence of the bus voltage. The amplitude of the current fluctuation is determined based on the amplitude corresponding to the dominant frequency of the current fluctuation in the charging current time sequence.

[0011] Furthermore, the silver plating wear analysis module also includes, The wear determination unit is used to determine the wear state of the silver plating layer at the electrical contact interface based on the changing trend of the contact resistance fluctuation rate. The first wear state is determined based on the fact that the contact resistance fluctuation rate does not show a sequential increasing trend along the time sequence of each charging process, the silver plating layer has not yet shown obvious wear, and the electrical contact interface is still in good condition. The second wear state is determined based on the fact that the contact resistance fluctuation rate increases sequentially with each charging process. The silver plating layer has shown obvious wear, exposing the copper substrate. There is a risk of oxide film formation and breakdown during subsequent charging processes.

[0012] Furthermore, the micro-arc state analysis module includes, The pulse frequency determination unit is used to determine the micro-arc pulse frequency based on the number of effective pulses identified as voltage spikes per unit time, so as to determine the occurrence frequency of oxide film breakdown micro-arcs. The voltage spike is determined based on a transient spike whose voltage amplitude exceeds the current noise amplitude and whose pulse width is less than a preset pulse width threshold, and is used to identify the discharge pulse generated at the moment of oxide film breakdown. The voltage amplitude is determined based on the instantaneous maximum voltage value of each pulse in the voltage signal; The voltage signal is determined based on the high-frequency sampling sequence of the bus voltage.

[0013] Furthermore, the micro-arc state analysis module also includes, A micro-arc determination unit is used to determine the micro-arc state of the electrical contact interface based on the changing trend of the micro-arc pulse frequency, wherein... The first micro-arc state is determined based on the fact that the frequency of the micro-arc pulse does not show a sequential increasing trend along the time sequence of each charging process, and a continuous oxide film breakdown micro-arc has not yet occurred at the electrical contact interface. The second micro-arc state is determined based on the fact that the frequency of the micro-arc pulse increases sequentially along the time sequence of each charging process, and a significant oxide film breakdown micro-arc has occurred at the electrical contact interface.

[0014] Furthermore, the contact resistance deterioration early warning module includes, The rising rate determination unit is used to determine the rising rate of dynamic contact resistance based on the slope of the change of dynamic contact resistance with time within a preset time window, so as to determine the long-term cumulative deterioration trend of contact resistance induced by micro-arc. The dynamic contact resistance time series is formed by arranging the instantaneous dynamic contact resistance at multiple consecutive sampling times in chronological order. The instantaneous dynamic contact resistance is determined based on the instantaneous values ​​of the bus voltage and the charging current, in order to determine the dynamic change waveform of the contact resistance over time.

[0015] Furthermore, the contact resistance deterioration early warning module also includes, A degradation determination unit is used to determine the degradation state of the contact resistance based on the trend of the rate of increase, wherein, The first deterioration state is determined based on the fact that the rate of increase increases sequentially along the time sequence of each charging process, indicating that the contact resistance has entered the deterioration stage. The second deterioration state is determined by the increasing rate of increase along the time sequence of each charging process, indicating that the contact resistance has entered the accelerated deterioration stage.

[0016] Furthermore, the contact resistance deterioration early warning module also includes, The early warning output unit is used to determine the corresponding early warning level based on the deterioration status output by the deterioration determination unit, wherein... The first warning level is based on the existence of a continuous increasing trend and the increase rate has not accelerated, and a first warning signal is output. The second warning level is determined based on the existence of a continuous increasing trend and the accelerating rate of increase, and outputs a second warning signal.

[0017] Compared with the prior art, the beneficial effects of this invention are as follows: By integrating a two-input, four-output high-voltage junction box housing structure and setting up a soft copper busbar assembly, terminal assembly, copper busbar sheath, and wire clamps inside, this invention achieves reliable transmission and physical protection of high voltage and high current. Based on this, sensor components are used to acquire the charging current timing sequence and the high-frequency sampling sequence of the bus voltage in real time. The silver plating wear analysis module extracts the contact resistance fluctuation rate based on current fluctuations and voltage response at the same frequency. The wear state of the silver plating layer is determined by its changing trend along the charging time sequence. The micro-arc state analysis module further utilizes voltage peak characteristics to further analyze the wear determination. By taking the frequency of micro-arc pulses and judging the state of oxide film breakdown micro-arc by its change trend along the charging time sequence, when micro-arcs continue to occur, their accumulated energy input becomes the key cause of accelerated deterioration of contact resistance. The contact resistance deterioration early warning module, based on the wear state and micro-arc state, further judges the contact resistance deterioration state based on the dynamic contact resistance rise rate and its historical trend along the charging time sequence and outputs an early warning signal. This realizes the monitoring of silver plating wear, oxide film breakdown micro-arc, and dynamic deterioration of contact resistance caused by charging current fluctuations and resonant coupling between soft copper busbar layers, which significantly improves the reliability and safety of high-voltage connector assembly.

[0018] Furthermore, this invention calculates the contact resistance fluctuation rate by combining the amplitude of the dynamic contact resistance fluctuation generated by the current fluctuation and the resonant coupling between the soft copper busbar layers with the static reference value, and determines the wear state based on the temporal trend of the fluctuation rate along each charging process. This can avoid misjudgment caused by the difference in operating conditions of different vehicles and charging piles, and can detect the wear in the early stage of silver plating wear before it causes obvious temperature rise or voltage drop abnormalities, thus significantly improving the preventive maintenance capability of the high-voltage connector assembly.

[0019] Furthermore, based on the determination of silver plating wear, this invention further utilizes the voltage spike characteristics in the high-frequency sampling sequence of bus voltage to achieve online identification of oxide film breakdown micro-arcs. Compared with the traditional method that only detects static contact resistance, it can detect this hidden transient discharge phenomenon of micro-arcs, providing accurate triggering conditions for subsequent contact resistance deterioration assessment. It avoids misjudging normal fluctuation signals when there are no micro-arcs, significantly improves the pertinence and reliability of diagnosis, and effectively prevents the risk of contact ablation caused by the accumulation of micro-arcs.

[0020] Furthermore, by calculating the instantaneous dynamic contact resistance in real time and extracting its rise rate, the present invention quantifies the long-term cumulative damage induced by micro-arcs into a monitorable deterioration rate. This allows for the detection of the deterioration trend of the electrical contact interface earlier than traditional static contact resistance measurement. At the same time, based on the historical trend of the rise rate, the deterioration state is determined and a corresponding level of warning signal is output, which significantly improves the reliability and safety of the high-voltage connector assembly. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the high-voltage connector assembly for power distribution in new energy vehicles according to an embodiment of the present invention; Figure 2 This is a circuit diagram of a high-voltage connector assembly for power distribution in new energy vehicles, according to an embodiment of the present invention. Figure 3 This is a module connection block diagram of a high-voltage connector assembly for power distribution in new energy vehicles, according to an embodiment of the present invention. Figure 4 This is a logic block diagram illustrating how the micro-arc state characteristics of the copper busbar contact surface are determined based on the micro-arc pulse frequency according to an embodiment of the present invention. In the diagram, 1 - metal top cover, 2 - plastic body, 3 - metal shell, 4 - terminal assembly, 5 - wire clamp, 601 - positive input busbar, 602 - negative input busbar, and 7 - copper busbar sheath. Detailed Implementation

[0022] To make the objectives and advantages of the present invention clearer, the present invention will be further described below with reference to embodiments; it should be understood that the specific embodiments described herein are merely for explaining the present invention and are not intended to limit the present invention.

[0023] Preferred embodiments of the present invention will now be described with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are merely illustrative of the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0024] It should be noted that in the description of this invention, the terms "upper", "lower", "left", "right", "inner", "outer", etc., which indicate directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings. This is only for the convenience of description and is not intended to indicate or imply that the device or element must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of this invention.

[0025] Please see Figure 1 , Figure 2 and Figure 3 As shown, the high-voltage connector assembly in this embodiment includes: Connector housing, used to integrate a high-voltage junction box for two-input, four-output power distribution in new energy vehicles; The connector housing includes a metal top cover 1 disposed at the uppermost part of the connector housing, a metal outer shell 3 disposed at the lower part of the metal top cover 1, and a plastic body 2 disposed inside the metal outer shell 3.

[0026] In this embodiment, the metal top cover 1 is a stamped metal cover plate, which serves as the top of the sealed plastic body to achieve IP protection and structural reinforcement; the metal outer shell 3 is a shielding shell formed by die casting of aluminum alloy or zinc alloy, which has electromagnetic shielding, mechanical protection and installation and fixing functions, and integrates high-voltage interlocking and locking structure; the plastic body 2 is an insulating injection molded part, which serves as an insulating support and positioning carrier for the internal soft copper busbar and terminal assembly to achieve electrical isolation between high-voltage circuits.

[0027] The conductive connection mechanism includes a flexible copper busbar assembly disposed on one side of the metal housing 3 and connected to the plastic body 2, a copper busbar sheath 7 sleeved at the opening between the flexible copper busbar assembly and the metal housing 3, and a terminal assembly 4 disposed inside the metal housing 3.

[0028] In this embodiment, the soft copper busbar assembly includes a positive input busbar 601 and a negative input busbar 602. The positive input busbar 601 and the negative input busbar 602 constitute a high-voltage DC busbar for conducting high voltage and high current. Mounting holes are provided at both ends of the positive input busbar 601 and the negative input busbar 602 for crimping with the terminal assembly 4. The copper busbar sleeve 7 is used to radially seal the opening between the soft copper busbar assembly and the metal shell 3 to prevent moisture and dust from entering the shell. The terminal assembly 4 adopts a copper alloy silver plating process and can be crimped or welded to the soft copper busbar assembly.

[0029] The wire clamp 5 is located at the tail of the connector housing to fix the cable, clamp the high-voltage cable, realize the stress relief of the cable and the tail sealing, and prevent the cable from being pulled and causing the terminal to loosen.

[0030] The sampling circuit includes a current sampling circuit for acquiring the timing sequence of the charging current flowing from the DC charging socket through the fast charging main relay into the junction box's positive input busbar, and a voltage sampling circuit for acquiring the high-frequency sampling sequence of the bus voltages flowing from the DC charging socket through the fast charging main relay into the junction box's positive and negative input busbars.

[0031] The data acquisition module is connected to the sampling circuit to acquire the charging current timing sequence and the high-frequency sampling sequence of the bus voltage in real time. The silver plating wear analysis module, which is connected to the data acquisition module, is used to determine the equivalent contact resistance fluctuation rate of the circuit where the positive input busbar and the negative input busbar are located based on the current fluctuation characteristics in the charging current time sequence and the same frequency voltage fluctuation characteristics in the high frequency sampling sequence of the busbar voltage, so as to determine the wear state of the silver plating layer at the electrical contact interface of the positive input busbar and the negative input busbar. The micro-arc state analysis module is connected to the data acquisition module and the wear analysis module respectively. It is used to determine the micro-arc pulse frequency based on the voltage spike characteristics in the high-frequency sampling sequence of the bus voltage, and to determine the micro-arc state of the electrical contact interface based on the changing trend of the micro-arc pulse frequency. The contact resistance deterioration early warning module is connected to the micro-arc state analysis module. It is used to determine the rate of increase of the equivalent contact resistance of the circuit containing the positive input busbar and the negative input busbar based on the charging current timing sequence and the high-frequency sampling sequence of the bus voltage. Based on the trend of the rate of increase, it determines the deterioration state of the contact resistance and outputs an early warning signal.

[0032] Specifically, this invention integrates a two-input, four-output high-voltage junction box housing structure, and internally incorporates a soft copper busbar assembly, terminal assembly, copper busbar sheath, and wire clamps, achieving reliable transmission and physical protection of high voltage and high current. Based on this, sensor components acquire real-time charging current timing sequences and high-frequency bus voltage sampling sequences. A silver plating wear analysis module extracts the contact resistance fluctuation rate based on current fluctuations and voltage response at the same frequency, determining the silver plating wear state by its trend along the charging time sequence. Furthermore, a micro-arc state analysis module, based on the wear determination, further extracts the micro-arc pulse frequency using voltage spike characteristics. Secondly, the state of oxide film breakdown micro-arc is determined by the trend of its change along the charging time sequence. When the micro-arc continues to occur, its accumulated energy input becomes the key cause of accelerated deterioration of contact resistance. The contact resistance deterioration early warning module, based on the wear state and micro-arc state, further determines the contact resistance deterioration state based on the dynamic contact resistance rise rate and its historical trend along the charging time sequence, and outputs an early warning signal. This realizes the monitoring of silver plating layer wear, oxide film breakdown micro-arc, and dynamic deterioration of contact resistance caused by charging current fluctuations and interlayer resonant coupling of soft copper busbar, which significantly improves the reliability and safety of high voltage connector assembly.

[0033] In this embodiment, the current sampling circuit includes a non-contact sensor based on the Hall effect. The sensor is sleeved on the section of the positive input busbar located on the input side of the metal casing to collect the instantaneous value of the current flowing from the DC charging socket through the fast charging main relay into the junction box of the positive input busbar, as a charging current timing sequence.

[0034] The voltage sampling circuit includes a sampling circuit based on resistor-capacitor voltage divider. Its input terminal is connected between the mounting hole of the positive input bus and the mounting hole of the negative input bus to collect the potential difference between the positive and negative input bus that flows from the DC charging socket through the fast charging main relay into the junction box. This difference serves as a high-frequency sampling sequence for the bus voltage, and the sampling frequency must meet the requirements for capturing nanosecond-level voltage spikes.

[0035] In this embodiment, the silver plating layer wear analysis module includes, The resistance fluctuation rate determination unit is used to determine the contact resistance fluctuation rate based on the ratio of the dynamic contact resistance fluctuation amplitude to the static contact resistance. This is used to determine the relative fluctuation of contact resistance caused by silver plating wear. The static contact resistance is determined based on the ratio of the steady-state voltage drop to the current between the positive and negative input busbars under rated DC current, when both are in an unworn state.

[0036] The dynamic contact resistance fluctuation amplitude is determined based on the ratio of the voltage fluctuation amplitude to the current fluctuation amplitude at the same frequency. The larger the value, the more violent the dynamic response of the electrical contact interface under the excitation of fluctuating current, and the more severe the wear of the silver plating layer. The smaller the value, the more stable the electrical contact interface.

[0037] The amplitude of voltage fluctuation at the same frequency is determined based on the high-frequency sampling sequence of the bus voltage.

[0038] The amplitude of the current fluctuation is determined based on the amplitude corresponding to the dominant frequency of the current fluctuation in the charging current time sequence.

[0039] The wear determination unit, connected to the resistance fluctuation determination unit, is used to determine the wear state of the silver plating layer at the electrical contact interface based on the changing trend of the contact resistance fluctuation rate. The first wear state is determined based on the fact that the contact resistance fluctuation rate does not show a sequential increasing trend along the time sequence of each charging process, the silver plating layer has not yet shown obvious wear, and the electrical contact interface is still in good condition. The second wear state is determined based on the fact that the contact resistance fluctuation rate increases sequentially with each charging process. The silver plating layer has shown obvious wear, exposing the copper substrate. There is a risk of oxide film formation and breakdown during subsequent charging processes.

[0040] Specifically, this invention calculates the contact resistance fluctuation rate by combining the amplitude of dynamic contact resistance fluctuation generated by the resonant coupling between the current fluctuation and the soft copper busbar layers with the static reference value, and determines the wear state based on the temporal trend of the fluctuation rate along each charging process. This can avoid misjudgment caused by differences in the operating conditions of different vehicles and charging piles, and can detect wear in the early stage of silver plating wear before it causes obvious temperature rise or voltage drop abnormalities, thus significantly improving the preventive maintenance capability of the high-voltage connector assembly.

[0041] In this embodiment, the dominant frequency of the current fluctuation is the frequency component with the largest amplitude, which is determined by performing a Fast Fourier Transform on the current time sequence output by the DC charging pile during the charging process. Those skilled in the art can reasonably select the window size and number of sampling points of the FFT according to the actual sampling rate and the required frequency resolution, and no specific limitation is made here.

[0042] In this embodiment, the amplitude of the voltage fluctuation at the same frequency is determined by extracting the peak value after bandpass filtering the high-frequency sampling sequence of the bus voltage at the same frequency as the main frequency of the current fluctuation. Those skilled in the art can reasonably select the order and bandwidth of the bandpass filter according to the signal characteristics and filtering requirements, and no specific limitation is made here.

[0043] In this embodiment, the bulk resistance of the positive input busbar and the negative input busbar is a fixed constant within the operating temperature range, and its change is much smaller than the change in the contact resistance of the electrical contact interface. Therefore, the dynamic change in the total resistance determined by the ratio of voltage to current is the dynamic change in the equivalent contact resistance of the electrical contact interface, and the contact resistance is the equivalent contact resistance.

[0044] In this embodiment, the contact resistance fluctuation rate of the historical charging process is stored in non-volatile memory and updated after each charging is completed.

[0045] Please see Figure 4 As shown, this is a logic block diagram of an embodiment of the present invention for determining the micro-arc state of an electrical contact interface based on the frequency of micro-arc pulses. In this embodiment, the micro-arc state analysis module includes: The pulse frequency determination unit is used to determine the micro-arc pulse frequency based on the number of effective pulses identified as voltage spikes per unit time, in order to determine the occurrence frequency of oxide film breakdown micro-arcs. Voltage spikes are determined based on transient spikes whose voltage amplitude exceeds the current noise amplitude and whose pulse width is less than a preset pulse width threshold, and are used to identify discharge pulses generated at the moment of oxide film breakdown.

[0046] The voltage amplitude is determined based on the instantaneous maximum voltage value of each pulse in the voltage signal.

[0047] The voltage signal is determined based on a high-frequency sampling sequence of the bus voltage.

[0048] A micro-arc determination unit, connected to a pulse frequency determination unit, is used to determine the micro-arc state of the electrical contact interface based on the changing trend of the micro-arc pulse frequency. The first micro-arc state is determined based on the fact that the frequency of the micro-arc pulse does not show a sequential increasing trend along the time sequence of each charging process, and a continuous oxide film breakdown micro-arc has not yet occurred at the electrical contact interface. The second micro-arc state is determined based on the increasing trend of the micro-arc pulse frequency along the time sequence of each charging process. The electrical contact interface has experienced obvious oxide film breakdown micro-arc, the electrical contact interface is in a dynamic discharge state, and there is a risk of accelerated deterioration of contact resistance.

[0049] In this embodiment, as the micro-arc continues to occur, the oxide film on the surface of the copper substrate is repeatedly broken down, and the damage to the electrical contact interface continues to accumulate. The frequency of the micro-arc pulse generally shows a continuous upward trend as the charging cycle progresses.

[0050] Specifically, this invention, based on the determination of silver plating wear, further utilizes the voltage spike characteristics in the high-frequency sampling sequence of bus voltage to achieve online identification of oxide film breakdown micro-arcs. Compared with the traditional method that only detects static contact resistance, it can detect this hidden transient discharge phenomenon of micro-arcs, providing accurate triggering conditions for subsequent contact resistance deterioration assessment. It avoids misjudging normal fluctuation signals when there are no micro-arcs, significantly improves the pertinence and reliability of diagnosis, and effectively prevents the risk of contact ablation caused by the accumulation of micro-arcs.

[0051] In this embodiment, the voltage signal is determined by high-pass filtering of the high-frequency sampling sequence of the bus voltage. Those skilled in the art can reasonably select the cutoff frequency and order of the high-pass filter based on the frequency domain characteristics of the micro-arc pulse and the sampling noise level, and no specific limitation is made here.

[0052] In this embodiment, the pulse width of the voltage spike is on the nanosecond level. Based on the typical duration of the micro-arc pulse, the preset pulse width threshold is 1μs, that is, only when the pulse width is less than 1μs is it counted as an effective voltage spike, so as to exclude wide pulse interference not caused by micro-arc.

[0053] In this embodiment, the current noise amplitude is determined by the peak-to-peak value of the voltage signal during the stable charging current period, and is used as a benchmark to judge whether the spike is significantly different from the background noise. The peak-to-peak value is the difference between the maximum and minimum values ​​of the voltage signal during the stable charging current period. If there are obvious abnormal pulses during this period, the statistical value after removing the abnormal values ​​can be used to determine the amplitude. No specific limitation is made here.

[0054] In this embodiment, the frequency of micro-arc pulses during the historical charging process is stored in a non-volatile memory and updated after each charging is completed; no specific limitation is made here.

[0055] In this embodiment, the contact resistance deterioration early warning module includes, The rising rate determination unit determines the rising rate of dynamic contact resistance based on the slope of the dynamic contact resistance change over time within a preset time window, which is used to determine the long-term cumulative deterioration trend of contact resistance under micro-arc induction. When the rising rate is positive, the contact resistance is in a state of continuous deterioration, and the larger the value, the faster the deterioration rate. When the rising rate is zero or negative, the contact resistance does not show a deterioration trend. The dynamic contact resistance time series is based on the instantaneous dynamic contact resistance at multiple consecutive sampling times arranged in chronological order.

[0056] Instantaneous dynamic contact resistance is determined based on the ratio of the instantaneous value of the bus voltage to the instantaneous value of the charging current, and is used to determine the dynamic change waveform of the contact resistance over time.

[0057] A degradation determination unit, connected to the rise rate determination unit, is used to determine the degradation state of the contact resistance based on the trend of the rise rate change. The first deterioration state is determined based on the fact that the rate of increase increases sequentially along the time sequence of each charging process, indicating that the contact resistance has entered the deterioration stage. The second deterioration state is determined by the increasing rate of increase along the time sequence of each charging process, indicating that the contact resistance has entered the accelerated deterioration stage.

[0058] In this embodiment, as the silver plating layer wears down and the micro-arc continues to act, the damage to the electrical contact interface accumulates continuously, and the rate of increase in dynamic contact resistance generally shows a continuous upward trend over a long-term scale.

[0059] The early warning output unit, connected to the deterioration determination unit, is used to determine the corresponding early warning level based on the deterioration status output by the deterioration determination unit. The first warning level is based on the existence of a continuous increasing trend and the increase rate has not accelerated. The first warning signal is output through the vehicle network.

[0060] The second warning level is determined based on the existence of a continuous increasing trend and the rate of increase is accelerating. The second warning signal is output through the vehicle network.

[0061] Specifically, this invention quantifies the long-term cumulative damage induced by micro-arcs into a monitorable deterioration rate by calculating the instantaneous dynamic contact resistance in real time and extracting its rise rate. This allows for the detection of the deterioration trend of the electrical contact interface earlier than traditional static contact resistance measurement. At the same time, based on the historical trend of the rise rate, the deterioration state is determined and a corresponding warning signal is output, which significantly improves the reliability and safety of the high-voltage connector assembly.

[0062] In this embodiment, the length of the preset time window is a value that can be reasonably determined by those skilled in the art based on the response time of the micro-arc to the contact resistance. In this embodiment, 10 seconds is preferred, but no specific limitation is made here.

[0063] In this embodiment, the instantaneous value of the bus voltage is read from the high-frequency sampling sequence of the bus voltage, and the instantaneous value of the charging current is read from the timing sequence of the charging current. No specific limitations are made here.

[0064] As an optional embodiment, the warning signal is a CAN message containing a warning level code, which is sent to the vehicle's instrument panel or in-vehicle infotainment system via the vehicle's CAN bus to display the corresponding prompt information or trigger the corresponding warning icon. The warning level code can be represented by a hexadecimal number, for example, 0x01 represents the first warning level and 0x02 represents the second warning level. The specific protocol format and encoding method of the warning signal can be adapted to the bus communication protocol of different vehicles, and are not specifically limited here.

[0065] The technical solution of the present invention has been described above with reference to the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the scope of protection of the present invention.

Claims

1. A high-voltage connector assembly device for new energy vehicle power distribution, comprising a connector housing, characterized in that, It also includes, A conductive connection mechanism is disposed inside and on the side of the connector housing to enable the conduction of high voltage and high current. The sampling circuit includes a current sampling circuit for acquiring the timing sequence of the charging current flowing from the DC charging socket through the fast charging main relay into the junction box's positive input busbar, and a voltage sampling circuit for acquiring the high-frequency sampling sequence of the bus voltages flowing from the DC charging socket through the fast charging main relay into the junction box's positive and negative input busbars. The data acquisition module is used to acquire the charging current timing sequence and the bus voltage high-frequency sampling sequence in real time. The silver plating wear analysis module is used to determine the equivalent contact resistance fluctuation rate of the circuit where the positive input busbar and the negative input busbar are located based on the current fluctuation characteristics in the charging current time sequence and the same frequency voltage fluctuation characteristics in the high frequency sampling sequence of the busbar voltage, so as to determine the wear state of the silver plating layer at the electrical contact interface between the positive input busbar and the negative input busbar. The micro-arc state analysis module is used to determine the micro-arc pulse frequency based on the voltage spike characteristics in the high-frequency sampling sequence of the bus voltage, and to determine the micro-arc state of the electrical contact interface based on the changing trend of the micro-arc pulse frequency. The contact resistance deterioration early warning module is used to determine the rate of increase of the equivalent contact resistance of the circuit containing the positive input busbar and the negative input busbar based on the charging current timing sequence and the high-frequency sampling sequence of the bus voltage, and to determine the deterioration state of the contact resistance based on the trend of the rate of increase, and output an early warning signal.

2. The high-voltage connector assembly for on-board power distribution in new energy vehicles according to claim 1, characterized in that, The conductive connection mechanism includes, A soft copper busbar assembly includes a positive input busbar and a negative input busbar disposed on one side of a metal housing and connected to a plastic body, for conducting high voltage and high current; A copper busbar sleeve is fitted over the opening between the flexible copper busbar assembly and the metal housing to achieve a radial seal at the opening between the flexible copper busbar assembly and the metal housing. Terminal assembly, which is disposed inside the metal housing.

3. The high-voltage connector assembly for on-board power distribution in new energy vehicles according to claim 2, characterized in that, The positive input busbar and the negative input busbar are respectively provided with mounting holes at both ends for connection to the terminal assembly.

4. The high-voltage connector assembly for on-board power distribution in new energy vehicles according to claim 3, characterized in that, The silver plating wear analysis module includes, The resistance fluctuation rate determination unit is used to determine the contact resistance fluctuation rate based on the ratio of the dynamic contact resistance fluctuation amplitude to the static contact resistance, in order to determine the relative fluctuation of contact resistance caused by the wear of the silver plating layer. Static contact resistance is determined based on the steady-state voltage drop and current between the positive input busbar and the negative input busbar in an unworn state under rated DC current. The amplitude of dynamic contact resistance fluctuation is determined based on the amplitude of voltage fluctuation and current fluctuation at the same frequency. The larger the fluctuation amplitude, the more intense the dynamic response of the electrical contact interface under the excitation of fluctuating current, and the more severe the wear of the silver plating layer. The amplitude of voltage fluctuation at the same frequency is determined based on the high-frequency sampling sequence of the bus voltage. The amplitude of the current fluctuation is determined based on the amplitude corresponding to the dominant frequency of the current fluctuation in the charging current time sequence.

5. The high-voltage connector assembly for on-board power distribution in new energy vehicles according to claim 4, characterized in that, The silver plating wear analysis module also includes, The wear determination unit is used to determine the wear state of the silver plating layer at the electrical contact interface based on the changing trend of the contact resistance fluctuation rate. The first wear state is determined based on the fact that the contact resistance fluctuation rate does not show a sequential increasing trend along the time sequence of each charging process, the silver plating layer has not yet shown obvious wear, and the electrical contact interface is still in good condition. The second wear state is determined based on the fact that the contact resistance fluctuation rate increases sequentially with each charging process. The silver plating layer has shown obvious wear, exposing the copper substrate. There is a risk of oxide film formation and breakdown during subsequent charging processes.

6. The high-voltage connector assembly for on-board power distribution in new energy vehicles according to claim 5, characterized in that, The micro-arc state analysis module includes, The pulse frequency determination unit is used to determine the micro-arc pulse frequency based on the number of effective pulses identified as voltage spikes per unit time, so as to determine the occurrence frequency of oxide film breakdown micro-arcs. The voltage spike is determined based on a transient spike whose voltage amplitude exceeds the current noise amplitude and whose pulse width is less than a preset pulse width threshold, and is used to identify the discharge pulse generated at the moment of oxide film breakdown. The voltage amplitude is determined based on the instantaneous maximum voltage value of each pulse in the voltage signal; The voltage signal is determined based on the high-frequency sampling sequence of the bus voltage.

7. The high-voltage connector assembly for on-board power distribution in new energy vehicles according to claim 6, characterized in that, The micro-arc state analysis module also includes, A micro-arc determination unit is used to determine the micro-arc state of the electrical contact interface based on the changing trend of the micro-arc pulse frequency, wherein... The first micro-arc state is determined based on the fact that the frequency of the micro-arc pulse does not show a sequential increasing trend along the time sequence of each charging process, and a continuous oxide film breakdown micro-arc has not yet occurred at the electrical contact interface. The second micro-arc state is determined based on the fact that the frequency of the micro-arc pulse increases sequentially along the time sequence of each charging process, and a significant oxide film breakdown micro-arc has occurred at the electrical contact interface.

8. The high-voltage connector assembly for on-board power distribution in new energy vehicles according to claim 7, characterized in that, The contact resistance deterioration early warning module includes, The rising rate determination unit is used to determine the rising rate of dynamic contact resistance based on the slope of the change of dynamic contact resistance with time within a preset time window, so as to determine the long-term cumulative deterioration trend of contact resistance induced by micro-arc. The dynamic contact resistance time series is formed by arranging the instantaneous dynamic contact resistance at multiple consecutive sampling times in chronological order. The instantaneous dynamic contact resistance is determined based on the instantaneous values ​​of the bus voltage and the charging current, in order to determine the dynamic change waveform of the contact resistance over time.

9. The high-voltage connector assembly for on-board power distribution in new energy vehicles according to claim 8, characterized in that, The contact resistance deterioration early warning module also includes, A degradation determination unit is used to determine the degradation state of the contact resistance based on the trend of the rate of increase, wherein, The first deterioration state is determined based on the fact that the rate of increase increases sequentially along the time sequence of each charging process, indicating that the contact resistance has entered the deterioration stage. The second deterioration state is determined by the increasing rate of increase along the time sequence of each charging process, indicating that the contact resistance has entered the accelerated deterioration stage.

10. The high-voltage connector assembly for on-board power distribution in new energy vehicles according to claim 9, characterized in that, The contact resistance deterioration early warning module also includes, The early warning output unit is used to determine the corresponding early warning level based on the deterioration status output by the deterioration determination unit, wherein... The first warning level is based on the existence of a continuous increasing trend and the increase rate has not accelerated, and a first warning signal is output. The second warning level is determined based on the existence of a continuous increasing trend and the accelerating rate of increase, and outputs a second warning signal.

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