COMBINED ELECTRICAL / FLUID CONNECTOR FOR AN ELECTRIFYED VEHICLE BATTERY

Abstract

An electrified vehicle system is depicted. The system includes a traction battery comprising a variety of electrically connected array modules immersed in a cooling fluid. A sensing component, coupled to at least one array module and immersed in the cooling fluid, is configured to detect a voltage drop when the fluid's contamination level reaches a threshold, thereby increasing its electrical conductivity. This detected voltage drop is communicated to a traction battery monitoring system, enabling proactive management of the cooling fluid's integrity.

Description

AREA OF TECHNOLOGY

[0001] This disclosure concerns battery cooling systems for use in electrified vehicles. GENERAL STATE OF THE ART

[0002] Immersion cooling systems provide a method for controlling the temperature in high-voltage battery systems, which include battery cells and exposed high-voltage components. However, maintaining proper electrical insulation in these systems is essential for performance. The dielectric strength of the immersion cooling fluid plays a role in this insulation. Contamination of the fluid can impair its dielectric properties. Conventional methods for detecting insulation faults between the high-voltage positive or negative terminal and the chassis ground are incapable of detecting dielectric breakdown in the cooling fluid caused by contamination. SUMMARY

[0003] One aspect of the disclosure describes an electrified vehicle system. This system includes a traction battery, a plurality of electrically connected array modules within the traction battery immersed in a cooling fluid, and a sensing component coupled to at least one of the array modules and in contact with the cooling fluid. The sensing component is configured to detect a voltage drop across the sensing component when an impurity level in the cooling fluid reaches a threshold that increases the electrical conductivity of the cooling fluid, and to report this voltage drop to a traction battery monitoring system. The sensing component can be a high-precision resistive shunt. Alternatively, the sensing component can be a current sensor with low- and high-precision range capabilities.In other configurations, the system of an electrified vehicle may also include a variety of sensing components, each coupled to a specific array module. The traction battery monitoring system may be configured to correlate the reported voltage drop with vehicle diagnostic data to determine the coolant contamination level. The traction battery monitoring system may also be configured to classify the coolant contamination level as low, medium, or high. Furthermore, the traction battery monitoring system may be configured to deactivate one of the array modules based on the contamination level. The traction battery may also be coupled to a traction component.

[0004] In another aspect of the disclosure, an electrified vehicle system is described. The electrified vehicle system includes a traction battery, at least one array within the traction battery immersed in a cooling fluid, and a sensing component within the cooling fluid configured to detect a change in the dielectric properties of the cooling fluid when an impurity level in the cooling fluid reaches a threshold that alters the dielectric strength of the cooling fluid, to measure the change in dielectric properties resulting from the voltage flow of the at least one array through the cooling fluid, and to communicate the measured change in dielectric properties to a traction battery monitoring system.The dielectric strength of the coolant is measured by the sensing component and can include at least one of the coolant's electrical conductivity, dielectric constant, or impedance. The sensing component can comprise multiple electrodes positioned at different locations within the coolant. The system of an electrified vehicle can further comprise multiple sensing components, each assigned to a different array within the traction battery. The traction battery monitoring system can also be configured to provide an initial measurement of the electrical properties and to detect deviations from this initial measurement. The traction battery monitoring system can further be configured to classify the deviation as indicating low, medium, or high contamination.The traction battery monitoring system can also be configured to correlate the measured change in electrical characteristics with vehicle diagnostic data to determine the level of coolant contamination. The diagnostic data may include coolant temperature measurements. Furthermore, the traction battery monitoring system can be configured to deactivate at least one array based on the measured change in electrical characteristics. The traction battery may be connected to a traction component.

[0005] In yet another aspect of the disclosure, a battery module is depicted. The battery module includes a housing with a plurality of arrays within the housing, an immersion coolant within the housing which is in contact with a positive and a negative terminal of the plurality of arrays, an impurity detection circuit coupled to at least one of the plurality of arrays and in contact with the immersion coolant, wherein the impurity detection circuit is configured to detect a current flow between the positive and negative terminals through the immersion coolant when an impurity level in the immersion coolant reaches a threshold that closes an electrical path, and a battery module monitoring system configured to provide data indicating the current flow.The battery module monitoring system receives information from the contamination detection circuit regarding the contamination level of the immersion cooling fluid and deactivates one of the multiple arrays based on a determination that the contamination level has reached the threshold. The system can also be configured to adjust the charging rate of the multiple arrays based on the determined contamination level. BRIEF DESCRIPTION OF THE DRAWINGS Fig. Figure 1 is a schematic diagram of a system of an electrified vehicle according to one or more aspects of the disclosure; Fig. 2 is a schematic diagram of a system of an electrified vehicle according to one or more aspects of the disclosure; and Fig. Figure 3 is a block diagram of a system of an electrified vehicle according to one or more aspects of the disclosure. DETAILED DESCRIPTION

[0006] Depending on the requirements, detailed embodiments of the claimed subject matter are disclosed in this document; however, it is understood that the disclosed embodiments are merely representative and can be implemented in various and alternative forms. The figures are not necessarily to scale; some features may be greatly enlarged or reduced to show details of certain components. Therefore, specific structural and functional details disclosed in this document are not to be interpreted as limiting, but merely as a representative basis to teach the person skilled in the art the diverse applications of the claimed subject matter.

[0007] The introduction of immersion cooling technology into high-voltage battery systems (HV systems) for electric vehicles has enabled new forms of thermal management and performance optimization. This approach, which involves immersing battery cells and associated HV components in a specifically formulated dielectric fluid, offers advantages over conventional air or liquid cooling methods. These advantages include improved heat transfer capabilities, a higher degree of uniform temperature distribution across the battery pack, and the potential for increased energy density. However, maintaining the integrity of the electrical insulation within the system can be challenging with immersion cooling technologies.

[0008] The dielectric fluid is a component of immersion cooling systems. It is a specifically engineered substance designed to balance several properties. An ideal immersion coolant possesses high dielectric strength to maintain electrical insulation, low viscosity for efficient circulation, high thermal conductivity for effective heat dissipation, chemical stability to prevent degradation under varying conditions, and low toxicity for environmental compatibility. Options for immersion cooling fluids include silicone oils, synthetic hydrocarbons, and specialized fluorinated fluids.Each type of fluid offers a profile of properties, and the selection process involves considering the specific requirements of the battery system, including considerations regarding the operating temperature range, expected lifespan, and stability.

[0009] The dielectric strength of the immersion cooling fluid plays a role in the stability and functionality of the high-voltage (HV) battery system. This dielectric strength allows the fluid to act as an effective insulator, preventing unintended electrical connections between HV components or between HV components and the vehicle chassis. However, the fluid's dielectric strength can be compromised by various forms of contamination. The ingress of moisture, even in minute quantities, can reduce the fluid's dielectric strength. Fine dust, which can enter the system from external sources or be generated internally through component wear, can create conductive pathways within the fluid. Over time, the fluid itself can undergo chemical degradation due to thermal stress or reactions with battery materials.In the event of cell damage, leakage of battery electrolyte into the cooling fluid can also impair its insulating properties. Methods for detecting insulation faults in high-voltage battery systems focus on monitoring the electrical insulation between either the positive (HV+) or negative (HV-) terminal and the chassis ground. These methods may not be sufficient to fully address the specific challenges posed by immersion cooling systems. One consideration for immersion-cooled systems is the possibility of a dual-fault scenario, where contamination of the cooling fluid can result in connections between both HV+ and HV- and the chassis ground. This scenario must be considered due to its impact on the battery and necessitates the development of improved detection and monitoring systems.

[0010] This disclosure presents an approach for detecting and monitoring dielectric breakdown in immersion-cooled high-voltage battery systems. The described system utilizes high-precision current measurement techniques to detect minute current flows that may indicate fluid contamination or the onset of dielectric breakdown. This is achieved by the placement of high-precision shunts or advanced current sensors capable of measuring currents in the microampere to milliampere range. These sensors are configured to detect the current flow through the cooling fluid between the HV+ and HV- components, thus providing early indication of potential insulation problems.

[0011] The current measurement system can be integrated into a battery management system (BMS) or dedicated battery pack sensor modules (BPSMs), enabling enhanced diagnostic capabilities. This analysis can correlate current measurements with a broad array of existing diagnostic data, including cell voltage imbalances, pack self-discharge rates, and temperature distribution anomalies. Algorithms can process this data to differentiate between normal operating currents and those indicative of dielectric breakdown, allowing the system to identify potential problems with high accuracy and minimal false positives.

[0012] The presented approach considers the implementation of insulation monitoring at the array or module level, rather than relying solely on pack-level testing. Each battery array can be equipped with its own BPSM capable of independently performing localized insulation tests. This granular approach allows for precise fault localization, enabling the system to differentiate between array-specific problems and system-wide contamination events. The distributed nature of this monitoring system improves overall reliability and provides data for predictive maintenance and fault diagnosis. Furthermore, the disclosure can integrate passive measurement techniques configured to operate with minimal power consumption. This allows for continuous vigilance for developing faults, even when the vehicle is at rest.The system can also perform rapid checks when waking up the BMS or BPSM to allow immediate detection of potential problems without significantly impacting the vehicle's energy efficiency.

[0013] Responding to detected faults can be managed through a tiered response system. The severity of the detected problem determines the appropriate action, ranging from activating diagnostic trouble codes or indicators for minor situations, to limiting charging / discharging rates or power output for more significant scenarios, to completely preventing the vehicle from starting and immediately logging the fault for the most serious events. This approach balances user convenience with operational reliability to maintain vehicle functionality whenever possible.

[0014] Integrating monitoring points within the fluid circulation system, which includes the pump and chiller controls, can enhance the system's detection capabilities. By utilizing both the high-voltage and low-voltage sides of the pump / chiller system for redundant testing, the presented approach can provide a comprehensive overview of fluid health throughout the entire circulation path.

[0015] The implementation of this detection system can involve specifically configured hardware and software components. High-precision resistance shunts or advanced Hall-effect sensors can be used for current measurement, capable of detecting even the slightest anomalies in the current flow. Furthermore, the BMS and BPSM software can incorporate machine learning algorithms that analyze current data in real time, taking into account factors such as normal leakage currents, temperature-dependent fluctuations in fluid conductivity, and transient currents during vehicle operation or charging.

[0016] Each BPSM can be equipped with dedicated microcontrollers capable of independently performing insulation tests, contributing to a robust and fault-tolerant system architecture. Data from all arrays can be aggregated and analyzed by the central BMS, which can employ pattern recognition techniques to identify and differentiate between systemic problems and localized faults. This distributed yet integrated approach allows for comprehensive monitoring while enabling fast and accurate fault diagnosis.

[0017] The passive measurement system can also integrate components with extremely low power consumption, allowing for periodic testing even during extended periods of vehicle inactivity. This can enable the detection of slowly developing faults that might otherwise go unnoticed between driving cycles, resulting in increased reliability and performance.

[0018] Fig. Figures 1-2 are schematic diagrams of a battery monitoring system 10 within the system of an electrified vehicle. The traction battery 12 has a high-voltage (HV) positive terminal 14 and a high-voltage (HV) negative terminal 16. The HV positive terminal 14 and the HV negative terminal 16 serve as the primary power lines for an electric vehicle's powertrain. The traction battery 12 incorporates several array modules (not shown individually in these figures) that are electrically interconnected to form a high-capacity energy storage system capable of supplying power to the vehicle's electric motors and auxiliary systems.

[0019] The immersion cooling fluid 18, which completely envelops the battery components, performs several functions. It provides heat dissipation from individual battery cells, ensures a uniform temperature distribution across the entire traction battery 12, and acts as a dielectric medium, maintaining electrical insulation between high-voltage components. Under normal operating conditions, the immersion cooling fluid 18 is configured to be non-conductive, thus preserving the electrical integrity of the battery system.

[0020] The battery monitoring system 10 includes a sensing component 20. The sensing component 20 can be a precision resistor / shunt, and this component is positioned in direct contact with the immersion cooling fluid 18. The primary function of the sensing component 20 is to measure minute current flows that may develop due to changes in the electrical properties of the immersion cooling fluid 18. The sensing component 20 can detect extremely small voltage drops across itself, which serve as sensitive indicators of changes in the electrical conductivity of the fluid.

[0021] System 10 includes a positive contactor 22 and a negative contactor 24. These are high-voltage switching devices that control the electrical connection between the traction battery 12 and a high-voltage load 26. These contactors 22 and 24 serve as measures that allow for the rapid electrical isolation of the battery 12 from the rest of the vehicle's high-voltage system in the event of a detected fault or during maintenance procedures.

[0022] A high-resistance component 28 provides the essential electrical insulation maintained between the traction battery 12 and the chassis ground 30. The high-resistance component 28 preserves the electrical integrity of the vehicle and effectively prevents unintended current paths between the traction battery 12 and any conductive body structure of the vehicle.

[0023] The high-voltage (HV) consumer 26 represents the electrical load from the various HV components in a vehicle that draw power from the traction battery 12. This can include, among other things, the electric drive motor, the power electronics for motor control, and HV heaters or air conditioning compressors. The chassis ground 30 provides a common reference point for all electrical vehicle systems and ensures that any stray currents have a predetermined path to ground.

[0024] The physical contact established by the immersion cooling fluid 18 with the HV positive terminal 14, the HV negative terminal 16, and the chassis ground 30 allows the immersion cooling fluid 18 to normalize the temperature of these components. Under normal circumstances, the dielectric properties of the immersion cooling fluid 18 prevent any current flow between these points. However, if contaminants enter the fluid and alter its electrical properties, potential current paths can form. The sensing component 20 is configured and positioned to detect these currents, which manifest as small but measurable voltage drops across the component.

[0025] The arrangement of the battery monitoring system 10, which is in Fig. As shown in Figures 1-2, continuous real-time monitoring of the cooling fluid's condition is possible. Any increase in the electrical conductivity of the immersion cooling fluid 18, which may be caused by the presence of conductive impurities 32 or a breakdown of the molecular structure of the immersion cooling fluid 18, can result in a detectable current flow through the sensing component 20. This current flow produces a voltage drop across the sensing component 20, which can be precisely measured and analyzed by the battery monitoring system 10. As shown in Fig. As shown in Figure 2, a circuit 34 is closed between the HV positive terminal 14 and the HV negative terminal 16 when the conductive impurities 32 have reached a threshold level.

[0026] Fig. Figure 3 is a block diagram of the entire system 36 of the electrified vehicle, showing the relationships between main components and subsystems. The traction battery 38 is a high-voltage battery pack that serves as the primary energy storage unit for an electrified vehicle, providing the necessary power to propel the vehicle and operate its numerous electrical systems. The traction battery 38 includes array modules and the battery monitoring system 10, which is located in Fig.As described in Figures 1-2, an onboard charger 40 is coupled to the traction battery 38. This onboard charger 40 converts alternating current power from external charging stations into direct current power required to charge the traction battery 38. The onboard charger 40, coupled to the traction battery 38, constitutes the high-voltage direct current charging circuit. This circuit can be designed to handle high power levels, often in the range of 50 to 350 kW, depending on the fast-charging capabilities of a vehicle.

[0027] Furthermore, the power electronics 42 is coupled to the traction battery 38. The power electronics 42 serves as the interface between the traction battery 38 and the traction motor 44. The power electronics 42 can include inverter systems that convert the DC power from the traction battery 38 into AC power required by the traction motor 44. Additionally, the power electronics 42 can manage a bidirectional power flow, enabling regenerative braking by converting kinetic energy back into electrical energy to recharge the battery 38. The power electronics 42 can be coupled to the traction motor 44, which may include high-voltage (HV) power circuits. The HV circuits can be configured to handle high currents, often exceeding 1000 amperes during peak load or regenerative braking events.

[0028] The traction motor 44 is the primary drive unit of the vehicle, responsible for converting electrical energy from the battery 38 into mechanical energy. The traction motor 44 can be of various types, such as permanent magnet synchronous motors or induction motors. The power electronics 42 coupled to the traction motor 44 constitute the high-voltage AC power circuit that supplies the controlled power with variable frequency and amplitude required to operate the traction motor 44 efficiently over a wide range of speeds and torques.

[0029] A battery management system 46 is the control unit of an electric powertrain that monitors and manages various aspects of the operation of the traction motor 44 and the traction battery 38. The battery management system 46 is connected to the traction battery 38, the power electronics 42, and the traction motor 44. These connections constitute the control and communication circuits that allow the battery management system to monitor and control these components. These circuits carry a multitude of signals, including battery cell voltage and temperature data, state-of-charge and health estimates, coolant contamination sensor data, power demand signals to the motor control, charging current and voltage control signals, and fault detection and mitigation commands.

[0030] A thermal management system 48 encloses the traction battery 38, the power electronics 42, and the traction motor 44. This system is responsible for maintaining optimal operating temperatures for these components. It includes an immersion cooling system for the traction battery 38 and may also include liquid or air cooling systems for the power electronics 42 and the traction motor 44. The thermal management system 48 plays a role in the efficiency, performance, and longevity of the electric powertrain components. It can incorporate advanced features such as heat pumps for passenger compartment climate control and battery preconditioning.

[0031] Power connections 50 between HV components carry the main power currents within the system, such as from the battery 38 to the motor 44 during high-load events or from the charger 40 to the battery 38 during charging. These circuits are designed to handle voltages that are typically in the range of 400 to 800 volts in modern electric vehicles, with some systems approaching 1000 volts for improved efficiency.

[0032] The control and communication links 52 allow the battery management system 46 to monitor and control various aspects of the powertrain operation. For example, the control and communication links 52 to the traction motor 44 carry speed and torque control signals, while the control and communication links 52 to the traction battery 38 include data from the thermal management system 48, individual cell voltages, temperatures, and other battery monitoring sensors. These communication links can use automotive-grade protocols, such as Controller Area Network, or other protocols, such as Automotive Ethernet.

[0033] Although representative embodiments have been described above, it is not intended that these embodiments describe all possible forms of the invention. Rather, the terms used in the patent specification are descriptive rather than limiting, and it is understood that various modifications can be made without departing from the claimed subject matter. Furthermore, the features of different implemented embodiments can be combined to form further embodiments within the scope of the claimed subject matter that are not expressly described or illustrated.

[0034] According to the present invention, an electrified vehicle system is provided comprising: a traction battery; a plurality of electrically connected array modules within the traction battery immersed in a cooling fluid; and a sensing component coupled to at least one of the electrically connected array modules and in contact with the cooling fluid, configured to detect a voltage drop across the sensing component when an impurity level in the cooling fluid reaches a threshold that increases the electrical conductivity of the cooling fluid, and to report a voltage drop across the sensing component to a traction battery monitoring system.

[0035] According to one embodiment, the detection component is a high-precision resistance shunt.

[0036] According to one embodiment, the sensing component is a current sensor with low and high precision range capabilities.

[0037] According to one embodiment, the invention is further characterized by a plurality of detection components, each of which is coupled to a respective array module.

[0038] According to one embodiment, the traction battery monitoring system is configured to correlate the reported voltage drop with diagnostic data from a vehicle in order to determine the level of contamination of the cooling fluid.

[0039] According to one embodiment, the traction battery monitoring system is further configured to classify the contamination level of the cooling fluid according to predetermined categories.

[0040] According to one embodiment, the traction battery monitoring system is further configured to deactivate one of the electrically connected array modules based on the level of contamination.

[0041] According to one embodiment, the traction battery is coupled to a traction component.

[0042] According to the present invention, an electrified vehicle system is provided comprising: a traction battery; at least one array within the traction battery immersed in a cooling fluid; and a sensing component within the cooling fluid configured to detect a change in the dielectric properties of the cooling fluid when an impurity level in the cooling fluid reaches a threshold that alters the dielectric strength of the cooling fluid, to measure the change in dielectric properties resulting from the voltage flow of the at least one array through the cooling fluid, and to communicate the measured change in dielectric properties to a traction battery monitoring system.

[0043] According to one embodiment, the dielectric strength of the cooling fluid is measured by the sensing component, which includes at least one of the electrical conductivity, dielectric constant or impedance of the cooling fluid.

[0044] According to one embodiment, the sensing component comprises several electrodes positioned at different locations within the cooling fluid.

[0045] According to one embodiment, the invention is further characterized by a plurality of detection components, each of which is assigned to a different array within the traction battery.

[0046] According to one embodiment, the traction battery monitoring system is configured to create an output measurement of the dielectric properties and to detect deviations from the output measurement.

[0047] According to one embodiment, the traction battery monitoring system is further configured to classify the deviations as one of a multitude of predefined categories.

[0048] According to one embodiment, the traction battery monitoring system is configured to correlate the measured change in electrical properties with vehicle diagnostic data to determine the level of coolant contamination. According to one embodiment, the diagnostic data includes temperature measurements of the coolant.

[0049] According to one embodiment, the traction battery monitoring system is further configured to deactivate the at least one array based on the measured change in electrical properties.

[0050] According to one embodiment, the traction battery is connected to a traction component.

[0051] According to the present invention, a battery module is provided comprising: a housing; a plurality of arrays within the housing; an immersion cooling fluid within the housing, which is in contact with a positive terminal and a negative terminal of the plurality of arrays; a contamination detection circuit coupled to at least one of the plurality of arrays and in contact with the immersion cooling fluid, wherein the contamination detection circuit is configured to detect a current flow between the positive terminal and the negative terminal through the immersion cooling fluid when a contamination level in the immersion cooling fluid reaches a threshold that closes an electrical path;and a battery module monitoring system configured to receive data indicating current flow due to a level of contamination in the immersion cooling fluid from the contamination detection circuit and to deactivate one of the multiple arrays based on the fact that the contamination level has reached the threshold.

[0052] According to one embodiment, the battery module monitoring system is further configured to set a charging rate for the plurality of arrays based on the contamination level.

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