Battery Insulation Resistance Measurement With Single-Terminal Circuit
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Solution Overview
Problem
Existing battery management systems require bulky and expensive components for insulation resistance measurement due to the need for connecting measurement circuits between both terminals of a battery pack and a chassis, which increases size and cost, especially with increasing battery voltages.
Innovation Solution
A method and apparatus for calculating battery resistance that connects the measurement circuit only between one terminal of the battery pack and the chassis, using a voltage division resistor and switch, and recalculates insulation resistance based on voltage changes and leakage current when the calculated value is below a threshold.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If measurement circuits are connected between both terminals of the battery pack and the chassis to measure insulation resistance, then measurement accuracy is improved, but the size and cost of the battery management system increases due to bulky and expensive components
Solution Approach 1:
The patent extracts the measurement circuit from the traditional dual-terminal configuration and repositions it to connect only to one terminal of the battery pack. By taking out the unnecessary connection to the second terminal, the system achieves the same insulation resistance measurement function using fewer components, thereby reducing size and cost while maintaining measurement accuracy
Solution Approach 2:
The patent introduces a switching element as an intermediary component that enables the measurement circuit to alternately connect to different terminals. This mediator allows the single measurement circuit to perform both measurement functions sequentially, eliminating the need for two separate measurement circuits and reducing overall system complexity
2Power
If high voltage battery packs are used in energy storage systems and electric vehicles, then power output is improved, but the requirement for high-end components increases, leading to higher cost
Solution Approach 1:
The patent employs periodic switching action where the measurement circuit alternately connects to different terminals through a switching element. This periodic measurement approach allows the system to handle high voltage battery packs using a single measurement circuit with switching capability, rather than requiring permanently connected high-end components for each terminal, thereby reducing overall component specification requirements and cost
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Reduces the size and cost of the battery management system while maintaining performance equivalent to conventional methods by recalculating insulation resistance using voltage changes and leakage current, thus improving accuracy for low values.
Implementation Method 1
a measurement circuit 210, which includes a measurement resistor and a switch connected in series, is connected between one of the positive (+) terminal and the negative (-) terminal of the battery pack and the chassis
Implementation Method 2
using a voltage division resistor and switch
Data Source
Figure 1
Figure 2
Figure 3A
AI summary
A battery resistance calculation apparatus according to one embodiment of the present invention comprises: a measurement circuit connected between a chassis and either the (+) terminal or the (-) terminal of a battery pack; a voltage measurement unit for measuring a voltage from the measurement circuit; and an insulation resistance calculation unit for calculating the insulation resistance of the battery pack on the basis of the voltage measured by the voltage measurement unit, wherein the insulation resistance calculation unit can re-calculate the insulation resistance on the basis of the voltage variation of the battery pack according to time if the calculated insulation resistance is less than a preset threshold.