On-Vehicle Battery Internal Resistance Measurement Using Drive Data
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Solution Overview
Problem
Existing methods for calculating the internal resistance of a battery cell are limited by the need to separate the battery from the vehicle, leading to temporal and spatial constraints that hinder accurate measurement during its operation.
Innovation Solution
An apparatus and method that calculates internal resistance by measuring current and voltage parameters of a battery cell mounted on a vehicle in its driving or simulated driving state, using a processor to collect and process data under predefined conditions to determine resistance values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the battery cell is separated from the vehicle for measurement, then the internal resistance can be measured using standard charger/discharger equipment, but the measurement cannot be performed during vehicle operation and requires battery removal
Solution Approach 1:
The battery management system performs self-measurement of internal resistance using the vehicle's existing powertrain components (motor, inverter, charger) instead of requiring external specialized equipment. The system utilizes normal charging/discharging operations to collect data and calculate internal resistance, eliminating the need for battery removal or separate measurement equipment.
Solution Approach 2:
The measurement system uses the vehicle's existing powertrain components (motor, inverter, charger) for dual purposes: both for normal vehicle operation and for internal resistance measurement. This multi-functional approach allows the same hardware to serve both operational and diagnostic functions without requiring dedicated measurement equipment.
2Productivity
If the battery remains mounted on the vehicle during measurement, then continuous monitoring is possible, but standard measurement methods cannot be applied due to electrical connections with vehicle components
Solution Approach 1:
The inverter acts as an intermediary component that enables measurement by providing isolated electrical connections. The system measures voltage at the inverter's DC input terminals, which are electrically connected to the battery but provide a measurement point that can be accessed without disrupting the battery's connection to the vehicle's electrical system.
Solution Approach 2:
The patent replaces the mechanical/physical measurement system (charger/discharger equipment requiring battery removal) with an electrical measurement system using the vehicle's existing power electronics. Instead of physical disconnection and specialized equipment, the system uses electrical signals and data processing through the inverter and BMS to measure internal resistance.
3Reliability
If continuous measurement is performed during vehicle operation, then real-time battery health data is available, but measurement conditions vary and may introduce errors
Solution Approach 1:
The system dynamically adjusts measurement parameters based on operating conditions. It selects appropriate measurement windows and calculation methods based on state of charge, temperature, and current levels to ensure accurate measurements across varying operational conditions rather than using fixed measurement protocols.
Solution Approach 2:
The system uses feedback from multiple sensors (voltage, current, temperature) to validate measurement conditions and adjust the measurement process. The BMS continuously monitors operating parameters and determines whether current conditions are suitable for measurement, ensuring data quality while maintaining continuous monitoring capability.
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
Enables accurate measurement of internal resistance without battery removal, improving the prediction and management of battery lifespan by compensating for measurement errors and providing reliable data for battery health assessment.
Implementation Method 1
the internal resistance of a battery cell is calculated based on an amount of voltage drop measured in a process of discharging a step current through a charger/discharger
Data Source
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AI summary
The present disclosure relates to an apparatus and method for calculating an internal resistance of a battery, and a computer program. The technical solution is to provide a topology capable of measuring an internal resistance of a battery cell even when the battery is mounted on a vehicle without the separation or removal of the battery from the vehicle. To this end, the present disclosure provides a configuration for calculating an internal resistance of a battery based on a current parameter and a voltage parameter of the battery when a data collection condition, which is predefined based on the discharge current characteristics of the battery in a driving state of a vehicle, is satisfied.