A method and apparatus for detecting battery leakage. The method includes determining whether an insulation resistance value difference is smaller than a preset reference difference when a representative insulation resistance value is larger than a preset reference resistance value, wherein the insulation resistance value difference is a difference between a previous representative insulation resistance value and the representative insulation resistance value, allocating a first value to a diagnosis flag when the insulation resistance value difference is smaller than the reference difference, allocating a second value to the diagnosis flag when the insulation resistance value difference is equal to or larger than the reference difference, and activating a count indicator when the second value is allocated to the diagnosis flag. The first value indicates that the representative insulation resistance value is valid. The second value indicates that the representative insulation resistance value is invalid.

A method for monitoring electrical insulation resistance in an electric system includes: supplying electric power from an external power supply via a first conductor and a second conductor; feeding the electric power to the electric system via a first current collector and a second current collector, each of which are configured to be electrically connected to the electric system via a first main contactor and a second main contactor, respectively; and monitoring the insulation resistance by means of an insulation resistance monitoring unit associated with a control unit and connected to each of the main contactors. The method further includes: maintaining the main contactors in a closed state when the current collectors are disconnected from the conductors, thereby allowing monitoring of the insulation resistance; opening the main contactors and subsequently connecting the current collectors to the conductors; and closing the main contactors thereby allowing monitoring of the insulation resistance. An arrangement for monitoring electrical insulation resistance in an electric system is also provided.

The present disclosure provides a battery detection circuit and a battery management system. The battery detection circuit includes a positive relay, a negative relay, a first positive sampling unit, a first negative sampling unit, a second positive sampling unit, a second negative sampling unit, and a reference voltage terminal, wherein: all of the first positive sampling unit, the first negative sampling unit, the second positive sampling unit, the second negative sampling unit and a power battery pack to be detected are connected to the reference voltage terminal. With the battery detection circuit and the battery management system of the present disclosure, both the cost of the battery detection circuit and the complexity of the structure of the battery detection circuit can be reduced.

The present disclosure provides an insulation detection device and method for an energy storage system. The insulation detection device includes a positive switching device, a negative switching device, a sampling unit, a reference voltage terminal and a processor. The sampling unit is configured to collect a positive sampled signal on the energy storage device when the positive switching device and the negative switching device are in a first switching state, and collect a negative sampled signal on the energy storage device when the positive switching device and the negative switching device are in a second switching state; and the processor is configured to determine a positive insulation resistance value and a negative insulation resistance value of the energy storage device according to the positive sampled signal and the negative sampled signal.

A high-voltage system including a high-voltage battery and a DC/DC converter, the high-voltage system having two different galvanically connected voltage levels with enabled DC/DC converters. A first measuring device detects the voltage of the high-voltage battery and a second measuring device detects the voltage at the output of the DC/DC converter. An insulation resistance measuring device may be configured to carry out insulation resistance measurements only when the DC/DC converter is disabled. A third measuring device may detect a voltage between a positive high voltage line and the ground and a fourth measuring device and a voltage between a negative high-voltage line and the ground. An insulation monitoring device may monitor the insulation resistances from data of the first to fourth measuring device at least when the DC/DC converter is enabled.

In a ground fault detection apparatus, a first charge voltage of a detection capacitor measured with a positive electrode side of a high-voltage battery connected in series with a positive electrode side end of the detection capacitor and a negative electrode side end of the detection capacitor grounded, is compared with a second charge voltage of the detection capacitor measured with the positive electrode side end of the detection capacitor grounded and the negative electrode side of the high-voltage battery connected in series with the negative electrode side end of the detection capacitor. When the first charge voltage is smaller and degree of smallness is greater than a predetermined reference, it is determined that positive electrode side insulation resistance is decreased. When the second charge voltage is smaller and degree of smallness is greater than a predetermined reference, it is determined that negative electrode side insulation resistance is decreased.

An active isolation detection method may be used with an electrical system having a battery pack connected to a high-voltage bus. The bus has positive and negative bus rails, each having a respective rail-to-ground voltage. The method may include connecting variable resistance element to the high-voltage bus, and determining input information indicative electrical characteristics of the battery pack, the high-voltage bus, and/or a charging station. The method includes varying a bias resistance of the high-voltage bus, via control of the variable resistance element, e.g., via duty cycle control of a binary switch in series with a bias resistor, to produce a varied bias resistance based on the input information. A target voltage shift is achieved on the high-voltage bus as a target level of change in one of the rail-to-ground voltages. An isolation resistance of the electrical system is determined via the controller using the varied bias resistance.

In at least one embodiment, an apparatus for monitoring isolation resistance in a vehicle is provided. The apparatus includes at least one controller that is configured to at least one of activate and deactivate any number of the plurality of switches and to perform a plurality of measurements on a high voltage system. The at least one controller is further configured to determine an isolation resistance between the high voltage system and the low voltage system based on the plurality of measurements and to determine a first resistance between the positive branch and a ground of the low voltage system based at least on the isolation resistance. The at least one controller is further configured to determine whether the isolation resistance of the high voltage system is exhibiting a symmetric failure, or an asymmetric failure based at least on the first resistance.

Embodiments of this application relate to the monitoring field, and disclose a method for monitoring an insulation monitoring circuit and a battery management system. In some embodiments of this application, the method for monitoring an insulation monitoring circuit includes: in a state in which a first switch and a second switch are closed and a third switch is open, obtaining a first electrical signal detected by a second monitoring module; and based on the first electrical signal and a voltage reference value between a positive electrode of a battery pack and a negative electrode of the battery pack, determining whether an insulation monitoring circuit is faulty; or obtaining a second electrical signal detected by a first monitoring module and a third electrical signal detected by a third monitoring module, and based on the second electrical signal and the third electrical signal, determining whether the insulation monitoring circuit is faulty.

A system may include a resistive-inductive-capacitive sensor, a driver configured to drive the resistive-inductive-capacitive sensor at a driving frequency, and a measurement circuit communicatively coupled to the resistive-inductive-capacitive sensor and configured to measure phase information associated with the resistive-inductive-capacitive sensor and based on the phase information, determine a displacement of a mechanical member relative to the resistive-inductive-capacitive sensor, wherein the displacement of the mechanical member causes a change in an impedance of the resistive-inductive-capacitive sensor.